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  • 1.
    Akerlind, C.
    et al.
    Swedish Def Res Agcy FOI, Div Electro Opt Systmes, SE-58111 Linkoping, Sweden.
    Hallberg, T.
    Swedish Def Res Agcy FOI, Div Electro Opt Systmes, SE-58111 Linkoping, Sweden.
    Järrendahl, Kenneth
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Optical Studies of White Organic Materials for Camouflage Applications in Arctic Environments2022Inngår i: TARGET AND BACKGROUND SIGNATURES VIII, SPIE-INT SOC OPTICAL ENGINEERING , 2022, Vol. 12270, artikkel-id 122700DKonferansepaper (Fagfellevurdert)
    Abstract [en]

    Important properties for camouflage materials can be summarized in six criteria: (1) spectrally selective reflectance, (2) low gloss, (3) low degree of polarization, (4) low infrared emissivity, (5) non-destructive effect on radar properties and (6) color adaptivity. We have studied a collection of natural materials for potential use as camouflage surfaces for the arctic region. The four first camouflage criteria are analyzed using spectrometry, scatterometry and spectroscopic ellipsometry techniques. The materials involved in the study are diffuse white nature-inspired surfaces: Cuticles of the beetle Cyphochilus insulanus, and foams of freeze-casted cellulose nanofibrils. We present data that partly fulfills the addressed camouflage criteria. An adequate reflectance is achieved in the spectral range of 400 - 1600 nm for both samples. Scattering data show that near-Lambertian properties are achieved at 633 nm for both surfaces but at 1550 nm for only the beetle cuticle. The degree of polarization is low for unpolarized light incident near the surface normal for both surfaces.

  • 2.
    Alarcon, Alvaro
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Argillander, Joakim
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Spegel-Lexne, Daniel
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Xavier, Guilherme B.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Quantum Random Number Generation Based on Spatial Modal Superposition over Few-Mode-Fibers2022Inngår i: Frontiers in Optics + Laser Science 2022 (FIO, LS), Optica Publishing Group , 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A quantum random number generator based on few-mode fiber technology is presented. The randomness originates from measurements of spatial modal quantum superpositions of the LP11a and LP11b modes. The generated sequences have passed NIST tests.

  • 3.
    Alarcon, Alvaro
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Argillander, Joakim
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Xavier, Guilherme B.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Creating Spatial States of Light for Quantum Information with Photonic Lanterns2021Inngår i: Applied Industrial Optics 2021 / [ed] G. Miller, A. Smith, I. Capraro, and J. Majors, Optical Society of America, 2021, artikkel-id W2A.2Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We demonstrate an all-fiber platform for the generation and detection of spatial photonic states where combinations of LP01, LP11a and LP11b modes are used. This scheme can be employed for quantum communication applications.

  • 4.
    Alarcon, Alvaro
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Gomez, Santiago
    Univ Concepcion, Chile; Univ Bio Bio, Chile.
    Spegel-Lexne, Daniel
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Argillander, Joakim
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Carine, Jaime
    Univ Catolica Santisima Concepcion, Chile.
    Canas, Gustavo
    Univ Bio Bio, Chile.
    Lima, Gustavo
    Univ Concepcion, Chile; Univ Concepcion, Chile.
    Xavier, Guilherme B
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    All-in-Fiber Dynamically Reconfigurable Orbital Angular Momentum Mode Sorting2023Inngår i: ACS Photonics, E-ISSN 2330-4022, Vol. 10, nr 10, s. 3700-3707Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The orbital angular momentum (OAM) spatial degree of freedom of light has been widely explored in many applications, including telecommunications, quantum information, and light-based micromanipulation. The ability to separate and distinguish between the different transverse spatial modes is called mode sorting or mode demultiplexing, and it is essential to recover the encoded information in such applications. An ideal d mode sorter should be able to faithfully distinguish between the different d spatial modes, with minimal losses, and have d outputs and fast response times. All previous mode sorters rely on bulk optical elements, such as spatial light modulators, which cannot be quickly tuned and have additional losses if they are to be integrated with optical fiber systems. Here, we propose and experimentally demonstrate, to the best of our knowledge, the first all-in-fiber method for OAM mode sorting with ultrafast dynamic reconfigurability. Our scheme first decomposes the OAM mode in-fiber-optical linearly polarized (LP) modes and then interferometrically recombines them to determine the topological charge, thus correctly sorting the OAM mode. In addition, our setup can also be used to perform ultrafast routing of the OAM modes. These results show a novel and fiber-integrated form of optical spatial mode sorting that can be readily used for many new applications in classical and quantum information processing.

    Fulltekst (pdf)
    fulltext
  • 5.
    Alarcon, Alvaro
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Xavier, Guilherme B.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    A few-mode fiber Mach-Zehnder interferometer for quantum communication applications2020Inngår i: Frontiers in Optics / Laser Science / [ed] B. Lee, C. Mazzali, K. Corwin, and R. Jason Jones, Optical Society of America, 2020, artikkel-id LM1F.6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We show that telecom few-mode fiber Mach-Zehnder interferometers can be used for quantum communication protocols where the LP01 and LP11a modes are employed to encode spatial qubits.

  • 6.
    AlSalhi, M S.
    et al.
    King Saud University, Saudi Arabia .
    Atif, M
    King Saud University, Saudi Arabia; National Institute of Laser and Optronics, Nilore, Islamabad, Pakistan.
    Ansari, A A.
    King Saud University, Saudi Arabia .
    Khun, Kimleang
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan. King Saud University, Riyadh, Saudi Arabia.
    Growth and characterization of ZnO nanowires for optical applications2013Inngår i: Laser physics, ISSN 1054-660X, E-ISSN 1555-6611, Vol. 23, nr 6, artikkel-id 065602Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, cerium oxide CeO2 nanoparticles were synthesized by the sol-gel method and used for the growth of ZnO nanorods. The synthesized nanoparticles were studied by x-ray diffraction (XRD) and Raman spectroscopic techniques. Furthermore, these nanoparticles were used as the seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by means of field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and XRD techniques. This study demonstrated that the grown ZnO nanorods are well aligned, uniform, of good crystal quality and have diameters of less than 200 nm. Energy dispersive x-ray (EDX) analysis revealed that the ZnO nanorods are composed only of zinc, cerium as the seed atom, and oxygen atoms, with no other impurities in the grown nanorods. Moreover, a photoluminescence (PL) approach was applied for the optical characterization, and it was observed that the near-band-edge (NBE) emission was the same as that of the zinc acetate seed layer, however the green and orange/red emission peaks were slightly raised due to possibly higher levels of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the controlled synthesis of ZnO nanorods using cerium oxide nanoparticles as the seed nucleation layer, improving both the morphology of the nanorods and the performance of devices based upon them.

  • 7.
    Amloy, Supaluck
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan. Department of Physics, Faculty of Science, Thaksin University, 93110 Phattalung, Thailand .
    Yu, K. H.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Karlsson, K Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Farivar, R.
    Applied Semiconductor Physics, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S‐41296 Göteborg, Sweden.
    Andersson, T. G.
    Applied Semiconductor Physics, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S‐41296 Göteborg, Sweden.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Polarized Emission from Single GaN Quantum Dots Grown by Molecular Beam Epitaxy2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Polarization resolved microphotoluminescence measurements of single MBE‐grown GaN/Al(Ga)N quantum dots (QDs) have been performed. The exciton and biexciton peaks with full width at half maximum as narrow as <500 μeV  were observed. Interestingly, there exist both positive and negative binding energies of the biexciton, explained in term of different sizes of the measured dots, resulting in different built‐in electric field. Moreover, a strongly linearly polarized emission is observed for the investigated dots with a degree of linear polarization of about 0.9, interpreted as the valence‐band mixing induced by in‐plane anisotropy due to strain and/or QD shape.

  • 8.
    An, Xiaoqiang
    et al.
    Tsinghua Univ, Peoples R China.
    Wei, Tingcha
    Tsinghua Univ, Peoples R China; Nanjing Univ Aeronaut & Astronaut, Peoples R China.
    Ding, Peijia
    Beihang Univ, Peoples R China.
    Liu, Li-Min
    Beihang Univ, Peoples R China.
    Xiong, Lunqiao
    UCL, England.
    Tang, Junwang
    UCL, England.
    Ma, Jiani
    Shanxi Normal Univ, Peoples R China.
    Wang, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Liu, Huijuan
    Tsinghua Univ, Peoples R China.
    Qu, Jiuhui
    Tsinghua Univ, Peoples R China.
    Sodium-Directed Photon-Induced Assembly Strategy for Preparing Multisite Catalysts with High Atomic Utilization Efficiency2023Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 145, nr 3, s. 1759-1768Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Integrating different reaction sites offers new prospects to address the difficulties in single-atom catalysis, but the precise regulation of active sites at the atomic level remains challenging. Here, we demonstrate a sodium-directed photon-induced assembly (SPA) strategy for boosting the atomic utilization efficiency of single-atom catalysts (SACs) by constructing multifarious Au sites on TiO2 substrate. Na+ was employed as the crucial cement to direct Au single atoms onto TiO2, while the light-induced electron transfer from excited TiO2 to Au(Na+) ensembles contributed to the self-assembly formation of Au nanoclusters. The synergism between plasmonic near-field and Schottky junction enabled the cascade electron transfer for charge separation, which was further enhanced by oxygen vacancies in TiO2. Our dual-site photocatalysts exhibited a nearly 2 orders of magnitude improvement in the hydrogen evolution activity under simulated solar light, with a striking turnover frequency (TOF) value of 1533 h(-1) that exceeded other Au/TiO2-based photocatalysts reported. Our SPA strategy can be easily extended to prepare a wide range of metal-coupled nanostructures with enhanced performance for diverse catalytic reactions. Thus, this study provides a well-defined platform to extend the boundaries of SACs for multisite catalysis through harnessing metal-support interactions.

    Fulltekst (pdf)
    fulltext
  • 9.
    Anderson, Christopher P.
    et al.
    Univ Chicago, IL 60637 USA; Univ Chicago, IL 60637 USA.
    Glen, Elena O.
    Univ Chicago, IL 60637 USA.
    Zeledon, Cyrus
    Univ Chicago, IL 60637 USA.
    Bourassa, Alexandre
    Univ Chicago, IL 60637 USA.
    Jin, Yu
    Univ Chicago, IL 60637 USA.
    Zhu, Yizhi
    Univ Chicago, IL 60637 USA.
    Vorwerk, Christian
    Univ Chicago, IL 60637 USA.
    Crook, Alexander L.
    Univ Chicago, IL 60637 USA; Univ Chicago, IL 60637 USA.
    Abe, Hiroshi
    Natl Inst Quantum Sci & Technol, Japan.
    Ul-Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Ohshima, Takeshi
    Natl Inst Quantum Sci & Technol, Japan.
    Nguyen, Son Tien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Galli, Giulia
    Univ Chicago, IL 60637 USA; Univ Chicago, IL 60637 USA; Argonne Natl Lab, IL 60439 USA.
    Awschalom, David D.
    Univ Chicago, IL 60637 USA; Univ Chicago, IL 60637 USA; Argonne Natl Lab, IL 60439 USA.
    Five-second coherence of a single spin with single-shot readout in silicon carbide2022Inngår i: Science Advances, E-ISSN 2375-2548, Vol. 8, nr 5, artikkel-id eabm5912Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An outstanding hurdle for defect spin qubits in silicon carbide (SiC) is single-shot readout, a deterministic measurement of the quantum state. Here, we demonstrate single-shot readout of single defects in SiC via spin-to-charge conversion, whereby the defects spin state is mapped onto a long-lived charge state. With this technique, we achieve over 80% readout fidelity without pre- or postselection, resulting in a high signal-to-noise ratio that enables us to measure long spin coherence times. Combined with pulsed dynamical decoupling sequences in an isotopically purified host material, we report single-spin T-2 &gt; 5 seconds, over two orders of magnitude greater than previously reported in this system. The mapping of these coherent spin states onto single charges unlocks both single-shot readout for scalable quantum nodes and opportunities for electrical readout via integration with semiconductor devices.

    Fulltekst (pdf)
    fulltext
  • 10.
    Andersson, Ake
    et al.
    Univ Gothenburg, Sweden.
    Yatsyna, Vasyl
    Univ Gothenburg, Sweden; Radboud Univ Nijmegen, Netherlands; Ecole Polytech Fed Lausanne, Switzerland.
    Linares, Mathieu
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. Ecole Polytech Fed Lausanne, Switzerland.
    Rijs, Anouk
    Radboud Univ Nijmegen, Netherlands; Vrije Univ Amsterdam, Netherlands.
    Zhaunerchyk, Vitali
    Univ Gothenburg, Sweden.
    Indication of 310-Helix Structure in Gas-Phase Neutral Pentaalanine2023Inngår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 127, nr 4, s. 938-945Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the gas-phase structure of the neutral pentaalanine peptide. The IR spectrum in the 340-1820 cm-1 frequency range is obtained by employing supersonic jet cooling, infrared multiphoton dissociation, and vacuum-ultraviolet action spectroscopy. Comparison with quantum chemical spectral calculations suggests that the molecule assumes multiple stable conformations, mainly of two structure types. In the most stable conformation theoretically found, the N-terminus forms a C5 ring and the backbone resembles that of an 310-helix with two beta-turns. Additionally, the conformational preferences of pentaalanine have been evaluated using Born-Oppenheimer molecular dynamics, showing that a nonzero simulation time step causes a systematic frequency shift.

    Fulltekst (pdf)
    fulltext
  • 11.
    Antonsson, Johan
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Eriksson, Ola
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Radio frequency electrode system for optical lesion size estimation in functional neurosurgery2005Inngår i: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 10, nr 3, s. 1-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Radiofrequency(RF) lesioning in the human brain is one possible surgicaltherapy for severe pain as well as movement disorders. Oneobstacle for a safer lesioning procedure is the lack ofsize monitoring. The aim of this study was to investigateif changes in laser Doppler or intensity signals could beused as markers for size estimation during experimental RF lesioning.A 2 mm in diameter monopolar RF electrode was equippedwith optical fibers and connected to a digital laser Dopplersystem. The optical RF electrode's performance was equal to astandard RF electrode with the same dimensions. An albumin solutionwith scatterers was used to evaluate the intensity and laserDoppler signal changes during lesioning at 70, 80, and 90 °C.Significant signal changes were found for these three different clotsizes, represented by the temperatures (p<0.05,  n=10). The volume, width, andlength of the created coagulations were correlated to the intensitysignal changes (r=0.88, n=30, p<0.0001) and to the perfusion signalchanges (r=0.81, n=30, p<0.0001). Both static and Doppler-shifted light canbe used to follow the lesioning procedure as well asbeing used for lesion size estimation during experimental RF lesioning.

  • 12.
    Applegate, Matthew B.
    et al.
    Boston Univ., United States.
    Karrobi, Kavon
    Boston Univ., United States.
    Angelo Jr., Joseph P.
    Univ. de Strasbourg, France.
    Austin, Wyatt M.
    The Univ. of Maine, United States.
    Tabassum, Syeda M.
    Boston Univ., United States.
    Aguénounon, Enagnon
    Univ. de Strasbourg, France.
    Tilbury, Karissa
    The Univ. of Maine, United States.
    Saager, Rolf B.
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Gioux, Sylvain
    Univ. de Strasbourg, France.
    Roblyer, Darren M.
    Boston Univ., United States.
    OpenSFDI: an open-source guide for constructing a spatial frequency domain imaging system2020Inngår i: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 25, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Significance: Spatial frequency domain imaging (SFDI) is a diffuse optical measurement technique that can quantify tissue optical absorption (μa) and reduced scattering (μ0 s) on a pixelby-pixel basis. Measurements of μa at different wavelengths enable the extraction of molar concentrations of tissue chromophores over a wide field, providing a noncontact and label-free means to assess tissue viability, oxygenation, microarchitecture, and molecular content. We present here openSFDI: an open-source guide for building a low-cost, small-footprint, threewavelength SFDI system capable of quantifying μa and μ0 s as well as oxyhemoglobin and deoxyhemoglobin concentrations in biological tissue. The companion website provides a complete parts list along with detailed instructions for assembling the openSFDI system. Aim: We describe the design of openSFDI and report on the accuracy and precision of optical property extractions for three different systems fabricated according to the instructions on the openSFDI website. Approach: Accuracy was assessed by measuring nine tissue-simulating optical phantoms with a physiologically relevant range of μa and μ0 s with the openSFDI systems and a commercial SFDI device. Precision was assessed by repeatedly measuring the same phantom over 1 h. Results: The openSFDI systems had an error of 0 6% in μa and −2 3% in μ0 s, compared to a commercial SFDI system. Bland–Altman analysis revealed the limits of agreement between the two systems to be 0.004 mm−1 for μa and −0.06 to 0.1 mm−1 for μ0 s. The openSFDI system had low drift with an average standard deviation of 0.0007 mm−1 and 0.05 mm−1 in μa and μ0 s, respectively. Conclusion: The openSFDI provides a customizable hardware platform for research groups seeking to utilize SFDI for quantitative diffuse optical imaging.

    Fulltekst (pdf)
    fulltext
  • 13.
    Aprilis, Georgios
    et al.
    Univ Bayreuth, Germany.
    Pakhomova, Anna
    Deutsch Elektronen Synchrotron DESY, Germany.
    Chariton, Stella
    Univ Bayreuth, Germany.
    Khandarkhaeva, Saiana
    Univ Bayreuth, Germany.
    Melai, Caterina
    Univ Bayreuth, Germany.
    Bykova, Elena
    Deutsch Elektronen Synchrotron DESY, Germany.
    Bykov, Maxim
    Univ Bayreuth, Germany.
    Fedotenko, Timofey
    Univ Bayreuth, Germany.
    Koemets, Egor
    Univ Bayreuth, Germany.
    McCammon, Catherine
    Univ Bayreuth, Germany.
    Chumakov, Aleksandr I
    ESRF European Synchrotron, France.
    Hanfland, Michael
    ESRF European Synchrotron, France.
    Doubrovinckaia, Natalia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Univ Bayreuth, Germany.
    Dubrovinsky, Leonid
    Univ Bayreuth, Germany.
    The Effect of Pulsed Laser Heating on the Stability of Ferropericlase at High Pressures2020Inngår i: Minerals, E-ISSN 2075-163X, MINERALS, Vol. 10, nr 6, artikkel-id 542Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is widely accepted that the lower mantle consists of mainly three major minerals-ferropericlase, bridgmanite and calcium silicate perovskite. Ferropericlase ((Mg,Fe)O) is the second most abundant of the three, comprising approximately 16-20 wt% of the lower mantle. The stability of ferropericlase at conditions of the lowermost mantle has been highly investigated, with controversial results. Amongst other reasons, the experimental conditions during laser heating (such as duration and achieved temperature) have been suggested as a possible explanation for the discrepancy. In this study, we investigate the effect of pulsed laser heating on the stability of ferropericlase, with a geochemically relevant composition of Mg0.76Fe0.24O (Fp24) at pressure conditions corresponding to the upper part of the lower mantle and at a wide temperature range. We report on the decomposition of Fp24 with the formation of a high-pressure (Mg,Fe)(3)O(4)phase with CaTi2O4-type structure, as well as the dissociation of Fp24 into Fe-rich and Mg-rich phases induced by pulsed laser heating. Our results provide further arguments that the chemical composition of the lower mantle is more complex than initially thought, and that the compositional inhomogeneity is not only a characteristic of the lowermost part, but includes depths as shallow as below the transition zone.

    Fulltekst (pdf)
    fulltext
  • 14.
    Argillander, Joakim
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Alarcon, Alvaro
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Bao, Chunxiong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten. Nanjing Univ, Peoples R China.
    Kuang, Chaoyang
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik.
    Lima, Gustavo
    Univ Concepcion, Chile.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Xavier, Guilherme B.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Quantum random number generation based on a perovskite light emitting diode2023Inngår i: Communications Physics, E-ISSN 2399-3650, Vol. 6, nr 1, artikkel-id 157Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    True random number generation is not thought to be possible using a classical approach but by instead exploiting quantum mechanics genuine randomness can be achieved. Here, the authors demonstrate a certified quantum random number generation using a metal-halide perovskite light emitting diode as a source of weak coherent polarisation states randomly producing an output of either 0 or 1. The recent development of perovskite light emitting diodes (PeLEDs) has the potential to revolutionize the fields of optical communication and lighting devices, due to their simplicity of fabrication and outstanding optical properties. Here we demonstrate that PeLEDs can also be used in the field of quantum technologies by implementing a highly-secure quantum random number generator (QRNG). Modern QRNGs that certify their privacy are posed to replace classical random number generators in applications such as encryption and gambling, and therefore need to be cheap, fast and with integration capabilities. Using a compact metal-halide PeLED source, we generate random numbers, which are certified to be secure against an eavesdropper, following the quantum measurement-device-independent scenario. The obtained generation rate of more than 10 Mbit s(-1), which is already comparable to commercial devices, shows that PeLEDs can work as high-quality light sources for quantum information tasks, thus opening up future applications in quantum technologies.

    Fulltekst (pdf)
    fulltext
  • 15.
    Argillander, Joakim
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Alarcon, Alvaro
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Xavier, Guilherme B.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    A tunable quantum random number generator based on a fiber-optical Sagnac interferometer2022Inngår i: Journal of Optics, ISSN 2040-8978, E-ISSN 2040-8986, Vol. 24, nr 6, artikkel-id 064010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quantum random number generators (QRNGs) are based on naturally random measurementresults performed on individual quantum systems. Here, we demonstrate a branching-pathphotonic QRNG implemented using a Sagnac interferometer with a tunable splitting ratio. Thefine-tuning of the splitting ratio allows us to maximize the entropy of the generated sequence ofrandom numbers and effectively compensate for tolerances in the components. By producingsingle-photons from attenuated telecom laser pulses, and employing commercially-availablecomponents we are able to generate a sequence of more than 2 gigabytes of random numberswith an average entropy of 7.99 bits/byte directly from the raw measured data. Furthermore, oursequence passes randomness tests from both the NIST and Dieharder statistical test suites, thuscertifying its randomness. Our scheme shows an alternative design of QRNGs based on thedynamic adjustment of the uniformity of the produced random sequence, which is relevant forthe construction of modern generators that rely on independent real-time testing of itsperformance.

    Fulltekst (pdf)
    fulltext
  • 16.
    Argillander, Joakim
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Alarcon, Alvaro
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Xavier, Guilherme B.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    All-fiber Dynamically Tunable Beamsplitter for Quantum Random Number Generators2022Inngår i: Latin America Optics and Photonics Conference / [ed] Optica Publishing Group, Optica Publishing Group , 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work we demonstrate an all-fiber dynamically tunable beamsplitter based on a Sagnac interferometer capable of realizing measurement-device independent protocols for certifying the privacy of the generated sequence.

  • 17. Bestill onlineKjøp publikasjonen >>
    Armakavicius, Nerijus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Study of novel electronic materials by mid-infrared and terahertz optical Hall effect2017Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Development of silicon based electronics have revolutionized our every day life during the last three decades. Nowadays Si based devices operate close to their theoretical limits that is becoming a bottleneck for further progress. In particular, for the growing field of high frequency and high power electronics, Si cannot offer the required properties. Development of materials capable of providing high current densities, carrier mobilities and high breakdown fields is crucial for a progress in state of the art electronics.

    Epitaxial graphene grown on semi-insulating silicon carbide substrates has a high potential to be integrated in the current planar device technologies. High electron mobilities and sheet carrier densities make graphene extremely attractive for high frequency analog applications. One of the remaining challenges is the interaction of epitaxial graphene with the substrate. Typically, much lower free charge carrier mobilities, compared to free standing graphene, and doping, due to charge transfer from the substrate, is reported. Thus, a good understanding of the intrinsic free charge carriers properties and the factors affecting them is very important for further development of epitaxial graphene.

    III-group nitrides have been extensively studied and already have proven their high efficiency as light sources for short wavelengths. High carrier mobilities and breakdown electric fields were demonstrated for III-group nitrides, making them attractive for high frequency and high power applications. Currently, In-rich InGaN alloys and AlGaN/GaN high electron mobility structures are of high interest for the research community due to open fundamental questions.

    Electrical characterization techniques, commonly used for the determination of free charge carrier properties, require good ohmic and Schottky contacts, which in certain cases can be difficult to achieve. Access to electrical properties of buried conductive channels in multilayered structures requires modification of samples and good knowledge of the electrical properties of all electrical contact within the structure. Moreover, the use of electrical contacts to electrically characterize two-dimensional electronic materials, such as graphene, can alter their intrinsic properties. Furthermore, the determination of effective mass parameters commonly employs cyclotron resonance and Shubnikov-de Haas oscillations measurements, which require long scattering times of free charge carriers, high magnetic fields and low temperatures.

    The optical Hall effect is an external magnetic field induced optical anisotropy in  conductive layers due to the motion of the free charge carriers under the influence of the Lorentz force, and is equivalent to the electrical Hall effect at optical frequencies. The optical Hall effect can be measured by generalized ellipsometry and provides a powerful method for the determination of free charge carrier properties in a non-destructive and contactless manner. In principle, a single optical Hall effect measurement can provide quantitative information about free charge carrier types, concentrations, mobilities and effective mass parameters at temperatures ranging from few kelvins to room temperature and above. Further, it was demonstrated that for transparent samples, a backside cavity can be employed to enhance the optical Hall effect.

    Measurement of the optical Hall effect by generalized ellipsometry is an indirect technique requiring subsequent data analysis. Parameterized optical models are fitted to match experimentally measured ellipsometric data by varying physically significant parameters. Analysis of the optical response of samples, containing free charge carriers, employing optical models based on the classical Drude model, which is augmented with an external magnetic field contribution, provide access to the free charge carrier properties.

    The main research results of the graduate studies presented in this licentiate thesis are summarized in the five scientific papers.

    Paper I. Description of the custom-built terahertz frequency-domain spectroscopic ellipsometer at Linköping University. The terahertz ellipsometer capabilities are demonstrated by an accurate determination of the isotropic and anisotropic refractive indices of silicon and m-plane sapphire, respectively. Further, terahertz optical Hall effect measurements of an AlGaN/GaN high electron mobility structures were employed to extract the two-dimensional electron gas sheet density, mobility and effective mass parameters. Last, in-situ optical Hall effect measurement on epitaxial graphene in a gas cell with controllable environment, were used to study the effects of environmental doping on the mobility and carrier concentration.

    Paper II. Presents terahertz cavity-enhanced optical Hall measurements of the monolayer and multilayer epitaxial graphene on semi-insulating 4H-SiC (0001) substrates. The data analysis revealed p-type doping for monolayer graphene with a carrier density in the low 1012 cm−2 range and a carrier mobility of 1550 cm2/V·s. For the multilayer epitaxial graphene, n-type doping with a carrier density in the low 1013 cm−2 range, a mobility of 470 cm2/V·s and an effective mass of (0.14 ± 0.03) m0 were extracted. The measurements demonstrate that cavity-enhanced optical Hall effect measurements can be applied to study electronic properties of two-dimensional materials.

    Paper III. Terahertz cavity-enhanced optical Hall effect measurements are employed to study anisotropic transport in as-grown monolayer, quasi free-standing monolayer and quasi free-standing bilayer epitaxial graphene on semi-insulating 4H-SiC (0001) substrates. The data analysis revealed a strong anisotropy in the carrier mobilities of the quasi freestanding bilayer graphene. The anisotropy is demonstrated to be induced by carriers scattering at the step edges of the SiC, by showing that the mobility is higher along the step than across them. The scattering mechanism is discussed based on the results of the optical Hall effect, low-energy electron microscopy, low-energy electron diffraction and Raman measurements.

    Paper IV. Mid-infrared spectroscopic ellipsometry and mid-infrared optical Hall effect measurements are employed to determine the electron effective mass in an In0.33Ga0.67N epitaxial layer. The data analysis reveals slightly anisotropic effective mass and carrier mobility parameters together with the optical phonon frequencies and broadenings.

    Paper V. Terahertz cavity-enhanced optical Hall measurements are employed to study the free charge carrier properties in a set of AlGaN/GaN high electron mobility structures with modified interfaces. The results show that the interface structure has a significant effect on the free charge carrier mobility and that the sample with a sharp interface between an AlGaN barrier and a GaN buffer layers exhibits a record mobility of 2332±73 cm2/V·s. The determined effective mass parameters showed an increase compared to the GaN value, that is attributed the the penetration of the electron wavefunction into the AlGaN barrier layer.

    Delarbeid
    1. Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Åpne denne publikasjonen i ny fane eller vindu >>Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Vise andre…
    2017 (engelsk)Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, s. 357-360Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cavity-enhanced optical Hall effect at terahertz (THz) frequencies is employed to determine the free charge carrier properties in epitaxial graphene (EG) with different number of layers grown by high-temperature sublimation on 4H-SiC(0001). We find that one monolayer (ML) EG possesses p-type conductivity with a free hole concentration in the low 1012 cmᅵᅵᅵ2 range and a free hole mobility parameter as high as 1550 cm2/Vs. We also find that 6 ML EG shows n-type doping behavior with a much lower free electron mobility parameter of 470 cm2/Vs and an order of magnitude higher free electron density in the low 1013 cmᅵᅵᅵ2 range. The observed differences are discussed. The cavity-enhanced THz optical Hall effect is demonstrated to be an excellent tool for contactless access to the type of free charge carriers and their properties in two-dimensional materials such as EG.

    sted, utgiver, år, opplag, sider
    Elsevier, 2017
    Emneord
    THz optical Hall effect, Epitaxial graphene, Free charge carrier properties
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132407 (URN)10.1016/j.apsusc.2016.10.023 (DOI)000408756700015 ()
    Merknad

    Funding agencies: Swedish Research Council (VR) [2013-5580]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486, 2014-04712]; Swedish foundation for strategic research (SSF) [FFL12-0181, RIF14-055]

    Tilgjengelig fra: 2016-11-09 Laget: 2016-11-09 Sist oppdatert: 2023-12-28bibliografisk kontrollert
    2. Properties of two-dimensional electron gas in AlGaN/GaN HEMT structures determined by cavity-enhanced THz optical Hall effect
    Åpne denne publikasjonen i ny fane eller vindu >>Properties of two-dimensional electron gas in AlGaN/GaN HEMT structures determined by cavity-enhanced THz optical Hall effect
    Vise andre…
    2016 (engelsk)Inngår i: Physica Status Solidi C-Current Topics in Solid State Physics, Vol 13 No 5-6, Wiley-VCH Verlagsgesellschaft, 2016, Vol. 13, nr 5-6, s. 369-373Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work we employ terahertz (THz) ellipsometry to determine two-dimensional electron gas (2DEG) density, mobility and effective mass in AlGaN/GaN high electron mobility transistor structures grown on 4H-SiC substrates. The effect of the GaN interface exposure to low-flow-rate trimethylaluminum (TMA) on the 2DEG properties is studied. The 2DEG effective mass and sheet density are determined tobe in the range of 0.30-0.32m0 and 4.3-5.5×1012 cm–2, respectively. The 2DEG effective mass parameters are found to be higher than the bulk effective mass of GaN, which is discussed in view of 2DEG confinement. It is shown that exposure to TMA flow improves the 2DEG mobility from 2000 cm2/Vs to values above 2200 cm2/Vs. A record mobility of 2332±61 cm2/Vs is determined for the sample with GaN interface exposed to TMA for 30 s. This improvement in mobility is suggested to be due to AlGaN/GaN interface sharpening causing the reduction of interface roughness scattering of electrons in the 2DEG.

    sted, utgiver, år, opplag, sider
    Wiley-VCH Verlagsgesellschaft, 2016
    Serie
    Physica Status Solidi C-Current Topics in Solid State Physics, ISSN 1862-6351
    Emneord
    AlGaN/GaN HEMTs, THz ellipsometry, 2DEG properties, THz optical Hall effect
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-133135 (URN)10.1002/pssc.201510214 (DOI)000387957200045 ()
    Konferanse
    11th International Conference on Nitride Semiconductors (ICNS), Beijing, China, August 30-September 4. 2015
    Tilgjengelig fra: 2016-12-12 Laget: 2016-12-09 Sist oppdatert: 2023-12-28bibliografisk kontrollert
    Fulltekst (pdf)
    Study of novel electronic materials by mid-infrared and terahertz optical Hall effect
    Download (pdf)
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    presentationsbild
  • 18.
    Armakavicius, Nerijus
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Bouhafs, Chamseddine
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Stanishev, Vallery
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Kühne, Philipp
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Knight, Sean
    Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, USA.
    Hofmann, Tino
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, USA / Department of Physics and Optical Science, University of North Carolina at Charlotte, USA.
    Schubert, Mathias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, USA.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies2017Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, s. 357-360Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cavity-enhanced optical Hall effect at terahertz (THz) frequencies is employed to determine the free charge carrier properties in epitaxial graphene (EG) with different number of layers grown by high-temperature sublimation on 4H-SiC(0001). We find that one monolayer (ML) EG possesses p-type conductivity with a free hole concentration in the low 1012 cmᅵᅵᅵ2 range and a free hole mobility parameter as high as 1550 cm2/Vs. We also find that 6 ML EG shows n-type doping behavior with a much lower free electron mobility parameter of 470 cm2/Vs and an order of magnitude higher free electron density in the low 1013 cmᅵᅵᅵ2 range. The observed differences are discussed. The cavity-enhanced THz optical Hall effect is demonstrated to be an excellent tool for contactless access to the type of free charge carriers and their properties in two-dimensional materials such as EG.

  • 19. Bestill onlineKjøp publikasjonen >>
    Aronsson, Christopher
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Tunable and modular assembly of polypeptides and polypeptide-hybrid biomaterials2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biomaterials are materials that are specifically designed to be in contact with biological systems and have for a long time been used in medicine. Examples of biomaterials range from sophisticated prostheses used for replacing outworn body parts to ordinary contact lenses. Currently it is possible to create biomaterials that can e.g. specifically interact with cells or respond to certain stimuli. Peptides, the shorter version of proteins, are excellent molecules for fabrication of such biomaterials. By following and developing design rules it is possible to obtain peptides that can self-assemble into well-defined nanostructures and biomaterials.

    The aim of this thesis is to create ”smart” and tunable biomaterials by molecular self-assembly using dimerizing –helical polypeptides. Two different, but structurally related, polypeptide-systems have been used in this thesis. The EKIV-polypeptide system was developed in this thesis and consists of four 28-residue polypeptides that can be mixed-and-matched to self-assemble into four different coiled coil heterodimers. The dissociation constant of the different heterodimers range from μM to < nM. Due to the large difference in affinities, the polypeptides are prone to thermodynamic social self-sorting. The JR-polypeptide system, on the other hand, consists of several 42-residue de novo designed helix-loop-helix polypeptides that can dimerize into four-helix bundles. In this work, primarily the glutamic acid-rich polypeptide JR2E has been explored as a component in supramolecular materials. Dimerization was induced by exposing the polypeptide to either Zn2+, acidic conditions or the complementary polypeptide JR2K.

    By conjugating JR2E to hyaluronic acid and the EKIV-polypeptides to star-shaped poly(ethylene glycol), respectively, highly tunable hydrogels that can be self-assembled in a modular fashion have been created. In addition, self-assembly of spherical superstructures has been investigated and were obtained by linking two thiol-modified JR2E polypeptides via a disulfide bridge in the loop region. ŒThe thesis also demonstrates that the polypeptides and the polypeptide-hybrids can be used for encapsulation and release of molecules and nanoparticles. In addition, some of the hydrogels have been explored for 3D cell culture. By using supramolecular interactions combined with bio-orthogonal covalent crosslinking reactions, hydrogels were obtained that enabled facile encapsulation of cells that retained high viability.

    The results of the work presented in this thesis show that dimerizing α–helical polypeptides can be used to create modular biomaterials with properties that can be tuned by specific molecular interactions. The modularity and the tunable properties of these smart biomaterials are conceptually very interesting andmake them useful in many emerging biomedical applications, such as 3D cell culture, cell therapy, and drug delivery

    .

    Delarbeid
    1. Self-sorting heterodimeric coiled coil peptides with defined and tuneable self-assembly properties
    Åpne denne publikasjonen i ny fane eller vindu >>Self-sorting heterodimeric coiled coil peptides with defined and tuneable self-assembly properties
    Vise andre…
    2015 (engelsk)Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 5, nr 14063Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Coiled coils with defined assembly properties and dissociation constants are highly attractive components in synthetic biology and for fabrication of peptide-based hybrid nanomaterials and nanostructures. Complex assemblies based on multiple different peptides typically require orthogonal peptides obtained by negative design. Negative design does not necessarily exclude formation of undesired species and may eventually compromise the stability of the desired coiled coils. This work describe a set of four promiscuous 28-residue de novo designed peptides that heterodimerize and fold into parallel coiled coils. The peptides are non-orthogonal and can form four different heterodimers albeit with large differences in affinities. The peptides display dissociation constants for dimerization spanning from the micromolar to the picomolar range. The significant differences in affinities for dimerization make the peptides prone to thermodynamic social self-sorting as shown by thermal unfolding and fluorescence experiments, and confirmed by simulations. The peptides self-sort with high fidelity to form the two coiled coils with the highest and lowest affinities for heterodimerization. The possibility to exploit self-sorting of mutually complementary peptides could hence be a viable approach to guide the assembly of higher order architectures and a powerful strategy for fabrication of dynamic and tuneable nanostructured materials.

    sted, utgiver, år, opplag, sider
    NATURE PUBLISHING GROUP, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-121739 (URN)10.1038/srep14063 (DOI)000361177400001 ()26370878 (PubMedID)
    Merknad

    Funding Agencies|Swedish Research Council (VR); Swedish Foundation for Strategic Research (SSF)

    Tilgjengelig fra: 2015-10-06 Laget: 2015-10-05 Sist oppdatert: 2022-09-15
    2. Tailoring Supramolecular Peptide-Poly(ethylene glycol) Hydrogels by Coiled Coil Self-Assembly and Self-Sorting
    Åpne denne publikasjonen i ny fane eller vindu >>Tailoring Supramolecular Peptide-Poly(ethylene glycol) Hydrogels by Coiled Coil Self-Assembly and Self-Sorting
    2016 (engelsk)Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, nr 6, s. 2260-2267Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Physical hydrogels are extensively used in a wide range of biomedical applications. However, different applications require hydrogels with different mechanical and structural properties. Tailoring these properties demands exquisite control over the supramolecular peptides with different affinities for dimerization. Four different mechanical properties of hydrogels using de novo designed coiled coil interactions involved. Here we show that it is possible to control the nonorthogonal peptides, designed to fold into four different coiled coil heterodimers with dissociation constants spanning from mu M to pM, were conjugated to star-shaped 4-arm poly(ethylene glycol) (PEG). The different PEG-coiled coil conjugates self-assemble as a result of peptide heterodimerization. Different combinations of PEG peptide conjugates assemble into PEG peptide networks and hydrogels with distinctly different thermal stabilities, supramolecular, and rheological properties, reflecting the peptide dimer affinities. We also demonstrate that it is possible to rationally modulate the self-assembly process by means of thermodynamic self-sorting by sequential additions of nonpegylated peptides. The specific interactions involved in peptide dimerization thus provides means for programmable and reversible self-assembly of hydrogels with precise control over rheological properties, which can significantly facilitate optimization of their overall performance and adaption to different processing requirements and applications.

    sted, utgiver, år, opplag, sider
    AMER CHEMICAL SOC, 2016
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-130135 (URN)10.1021/acs.biomac.6b00528 (DOI)000377924800038 ()27219681 (PubMedID)
    Merknad

    Funding Agencies|Swedish Research Council [621-2011-4319]; Swedish Foundation for Strategic Research [ICA10-0002]; Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]

    Tilgjengelig fra: 2016-07-12 Laget: 2016-07-11 Sist oppdatert: 2019-01-22
    3. Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix-Loop-Helix Peptide Superstructures for Controlled Encapsulation and Release
    Åpne denne publikasjonen i ny fane eller vindu >>Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix-Loop-Helix Peptide Superstructures for Controlled Encapsulation and Release
    2016 (engelsk)Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 49, nr 18, s. 6997-7003Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We demonstrate a novel route for hierarchical self-assembly of sub-micrometer-sized peptide superstructures that respond to subtle changes in Zn2+ concentration. The self-assembly process is triggered by a specific folding-dependent coordination of Zn2+ by a de novo designed nonlinear helix-loop-helix peptide, resulting in a propagating fiber formation and formation of spherical superstructures. The superstructures further form larger assemblies that can be completely disassembled upon removal of Zn2+ or degradation of the nonlinear peptide. This flexible and reversible assembly strategy of the superstructures enables facile encapsulation of nanoparticles and drugs that can be released by means of different stimuli.

    sted, utgiver, år, opplag, sider
    AMER CHEMICAL SOC, 2016
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132215 (URN)10.1021/acs.macromol.6b01724 (DOI)000384399100030 ()
    Merknad

    Funding Agencies|Swedish Research Council [621-2011-4319]; Swedish Foundation for Strategic Research [ICA10-0002]; Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]

    Tilgjengelig fra: 2016-10-26 Laget: 2016-10-21 Sist oppdatert: 2019-01-22
    Fulltekst (pdf)
    Tunable and modular assembly of polypeptides and polypeptide-hybrid biomaterials
    Download (pdf)
    omslag
    Download (jpg)
    presentationsbild
  • 20.
    Arpa Gonzalez, Enrique Manuel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska fakulteten. Univ Autonoma Madrid, Spain.
    Corral, Ines
    Univ Autonoma Madrid, Spain.
    Unveiling Photodegradation and Photosensitization Mechanisms of Unconjugated Pterins2023Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Invited for the cover of this issue are Enrique M. Arpa (Linkoping University) and Ines Corral (Universidad Autonoma de Madrid). The image depicts two examples where pterin chemistry is relevant, the wing coloration of some butterflies and the cytotoxic action in vitiligo. Read the full text of the article at 10.1002/chem.202300519.

  • 21.
    Arwin, Hans
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Magnusson, Roger
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Fernández del Río, Lia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Landin, Jan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ekologi. Linköpings universitet, Tekniska högskolan.
    Mendoza-Galván, Arturo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan. Unidad Queretaro, Queretaro, Mexico.
    Järrendahl, Kenneth
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Exploring polarization features in light reflection from beetles with structural colors2015Inngår i: Proc. SPIE  9429, Bioinspiration, Biomimetics, and Bioreplication 2015, SPIE - International Society for Optical Engineering, 2015, Vol. 9429, s. 942909-1-942909-13Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A Mueller matrix of a sample can be used to determine the polarization of  reflected light  for  incident light with arbitrary polarization. The polarization can be quantified  in terms of ellipticity, polarization azimuth and degree of polarization. We apply spectroscopic Mueller-matrix ellipsometry at multiple angles of incidence  to study the cuticle of beetles and derive  polarization features for incident unpolarized light.  In particular we address chiral phenomena in scarab beetles,  the origin of their structural colors and the observed high degree of circular polarization is discussed. Results from beetles in the Scarabaeidae subfamilies Cetoniinae and Rutelinae are presented including specimens with broad-band silver- or gold-like colors with metallic shine as well as specimens with narrow-band green or red reflectors. The variation of polarization with angle of incidence and occurrence of both left-handed and right-handed polarization from a single species are presented. We also use Mueller-matrix spectra in electromagnetic modeling and show how to determine structural parameters including cuticle layer thicknesses and optical properties. Interference oscillations in the observed spectra are due to allowed optical modes and we show how to develop a structural model of a cuticle based on this effect. Sum decomposition of  Mueller matrices measured on a depolarizing cuticle of a beetle is briefly discussed.

    Fulltekst (pdf)
    fulltext
  • 22.
    Arwin, Hans
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Magnusson, Roger
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Järrendahl, Kenneth
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schoeche, Stefan
    JA Woollam Co Inc, NE 68508 USA.
    Effective structural chirality of beetle cuticle determined from transmission Mueller matrices using the Tellegen constitutive relations2020Inngår i: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics, ISSN 2166-2746, E-ISSN 2166-2754, Vol. 38, nr 1, artikkel-id 014004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several beetle species in the Scarabaeoidea superfamily reflect left-handed polarized light due to a circular Bragg structure in their cuticle. The right-handed polarized light is transmitted. The objective here is to evaluate cuticle chiral properties in an effective medium approach using transmission Mueller matrices assuming the cuticle to be a bianisotropic continuum. Both differential decomposition and nonlinear regression were used in the spectral range of 500-1690nm. The former method provides the sample cumulated birefringence and dichroic optical properties and is model-free but requires a homogeneous sample. The materials chirality is deduced from the circular birefringence and circular dichroic spectra obtained. The regression method requires dispersion models for the optical functions but can also be used in more complex structures including multilayered and graded media. It delivers the material properties in terms of model functions of materials permittivity and chirality. The two methods show excellent agreement for the complex-valued chirality spectrum of the cuticle.

    Fulltekst (pdf)
    fulltext
  • 23.
    Arwin, Hans
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska fakulteten.
    Mendoza-Galvan, A.
    Cinvestav IPN, Mexico.
    Magnusson, Roger
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska fakulteten.
    Andersson, Anette
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Landin, Jan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ekologi. Linköpings universitet, Tekniska fakulteten.
    Järrendahl, Kenneth
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska fakulteten.
    Garcia-Caurel, E.
    University of Paris Saclay, France.
    Ossikovski, R.
    University of Paris Saclay, France.
    Structural circular birefringence and dichroism quantified by differential decomposition of spectroscopic transmission Mueller matrices from Cetonia aurata2016Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 41, nr 14, s. 3293-3296Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transmission Mueller-matrix spectroscopic ellipsometry is applied to the cuticle of the beetle Cetonia aurata in the spectral range 300-1000 nm. The cuticle is optically reciprocal and exhibits circular Bragg filter features for green light. By using differential decomposition of the Mueller matrix, the circular and linear birefringence as well as dichroism of the beetle cuticle are quantified. A maximum value of structural optical activity of 560 degrees/mm is found. (C) 2016 Optical Society of America

    Fulltekst (pdf)
    fulltext
  • 24.
    Askari Ghotbabadi, Sadegh
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. University of Ulster, North Ireland.
    Ul Haq, Atta
    University of Ulster, North Ireland.
    Macias-Montero, Manuel
    University of Ulster, North Ireland.
    Levchenko, Igor
    Queensland University of Technology, Australia.
    Yu, Fengjiao
    University of St Andrews, Scotland.
    Zhou, Wuzong
    University of St Andrews, Scotland.
    (Ken) Ostrikov, Kostya
    Queensland University of Technology, Australia; Queensland University of Technology, Australia; CSIRO, Australia.
    Maguire, Paul
    University of Ulster, North Ireland.
    Svrcek, Vladimir
    National Institute Adv Ind Science and Technology, Japan.
    Mariotti, Davide
    University of Ulster, North Ireland.
    Ultra-small photoluminescent silicon-carbide nanocrystals by atmospheric-pressure plasmas2016Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 8, nr 39, s. 17141-17149Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Highly size-controllable synthesis of free-standing perfectly crystalline silicon carbide nanocrystals has been achieved for the first time through a plasma-based bottom-up process. This low-cost, scalable, ligand-free atmospheric pressure technique allows fabrication of ultra-small (down to 1.5 nm) nanocrystals with very low level of surface contamination, leading to fundamental insights into optical properties of the nanocrystals. This is also confirmed by their exceptional photoluminescence emission yield enhanced by more than 5 times by reducing the nanocrystals sizes in the range of 1-5 nm, which is attributed to quantum confinement in ultra-small nanocrystals. This method is potentially scalable and readily extendable to a wide range of other classes of materials. Moreover, this ligand-free process can produce colloidal nanocrystals by direct deposition into liquid, onto biological materials or onto the substrate of choice to form nanocrystal films. Our simple but efficient approach based on non-equilibrium plasma environment is a response to the need of most efficient bottom-up processes in nanosynthesis and nanotechnology.

    Fulltekst (pdf)
    fulltext
  • 25.
    Aslandukova, Alena
    et al.
    Univ Bayreuth, Germany.
    Aslandukov, Andrey
    Univ Bayreuth, Germany.
    Laniel, Dominique
    Univ Edinburgh, Scotland.
    Yin, Yuqing
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Univ Bayreuth, Germany; Shandong Univ, Peoples R China.
    Akbar, Fariia Iasmin
    Univ Bayreuth, Germany.
    Bykov, Maxim
    Univ Cologne, Germany.
    Fedotenko, Timofey
    Deutsch Elektronen Synchrotron DESY, Germany.
    Glazyrin, Konstantin
    Deutsch Elektronen Synchrotron DESY, Germany.
    Pakhomova, Anna
    European Synchrotron Radiat Facil, France.
    Garbarino, Gaston
    European Synchrotron Radiat Facil, France.
    Bright, Eleanor Lawrence
    European Synchrotron Radiat Facil, France.
    Wright, Jonathan
    European Synchrotron Radiat Facil, France.
    Hanfland, Michael
    European Synchrotron Radiat Facil, France.
    Chariton, Stella
    Univ Chicago, IL 60637 USA.
    Prakapenka, Vitali
    Univ Chicago, IL 60637 USA.
    Doubrovinckaia, Natalia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Univ Bayreuth, Germany.
    Dubrovinsky, Leonid
    Univ Bayreuth, Germany.
    Diverse high-pressure chemistry in Y-NH3BH3 and Y–paraffin oil systems2024Inngår i: Science Advances, E-ISSN 2375-2548, Vol. 10, nr 11, artikkel-id eadl5416Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The yttrium-hydrogen system has gained attention because of near-ambient temperature superconductivity reports in yttrium hydrides at high pressures. We conducted a study using synchrotron single-crystal x-ray diffraction (SCXRD) at 87 to 171 GPa, resulting in the discovery of known (two YH3 phases) and five previously unknown yttrium hydrides. These were synthesized in diamond anvil cells by laser heating yttrium with hydrogen-rich precursors-ammonia borane or paraffin oil. The arrangements of yttrium atoms in the crystal structures of new phases were determined on the basis of SCXRD, and the hydrogen content estimations based on empirical relations and ab initio calculations revealed the following compounds: Y3H11, Y2H9, Y4H23, Y13H75, and Y4H25. The study also uncovered a carbide (YC2) and two yttrium allotropes. Complex phase diversity, variable hydrogen content in yttrium hydrides, and their metallic nature, as revealed by ab initio calculations, underline the challenges in identifying superconducting phases and understanding electronic transitions in high-pressure synthesized materials.

  • 26.
    Atlasov, K. A.
    et al.
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Surrente, A.
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Calic, M.
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Karlsson, K Fredrik
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Gallo, P.
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Felici, Marco
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Dwir, Benjamin
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Rudra, Alok
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Kapon, E.
    Lab. of Phys. of Nanostruct., Ecole Polytech. Fed. de Lausanne (EPFL), Lausanne, Switzerland .
    Site-controlled quantum-wire and quantum-dot photonic-crystal microcavity lasers2010Inngår i: Photonics Society Winter Topicals Meeting Series (WTM), 2010 IEEE, 2010, s. 149-150Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Based on site- and energy-controlled quantum wires (QWR) and quantum dots (QD), diverse photonic-crystal microcavity laser systems are proposed and discussed. Results demonstrating QWR lasing, cavity coupling and QD ordered arrays are presented.

  • 27.
    Backis, A.
    et al.
    Univ Glasgow, Scotland; European Spallat Source ERIC ESS, Sweden.
    Khaplanov, A.
    European Spallat Source ERIC ESS, Sweden.
    Al Jebali, R.
    Univ Glasgow, Scotland; European Spallat Source ERIC ESS, Sweden.
    Ammer, R.
    European Spallat Source ERIC ESS, Sweden.
    Apostolidis, I
    European Spallat Source ERIC ESS, Sweden.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lai, Chung-Chuan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. European Spallat Source ERIC ESS, Sweden.
    Deen, P. P.
    European Spallat Source ERIC ESS, Sweden; Univ Copenhagen, Denmark.
    Etxegarai, M.
    European Spallat Source ERIC ESS, Sweden.
    de Ruette, N.
    European Spallat Source ERIC ESS, Sweden.
    Ramos, J. Freita
    European Spallat Source ERIC ESS, Sweden.
    Foerster, D. F.
    Forschungszentrum Julich, Germany.
    Haettner, E.
    European Spallat Source ERIC ESS, Sweden.
    Hall-Wilton, R.
    Univ Glasgow, Scotland; European Spallat Source ERIC ESS, Sweden; Univ Milano Bicocca, Italy.
    Hamilton, D.
    Univ Glasgow, Scotland.
    Hoglund, C.
    European Spallat Source ERIC ESS, Sweden; Impact Coatings AB, Westmansgatan 29G, SE-58216 Linkoping, Sweden.
    Kadletz, P. M.
    European Spallat Source ERIC ESS, Sweden.
    Kanaki, K.
    European Spallat Source ERIC ESS, Sweden.
    Karnickis, E.
    European Spallat Source ERIC ESS, Sweden.
    Kirstein, O.
    European Spallat Source ERIC ESS, Sweden.
    Kolya, S.
    European Spallat Source ERIC ESS, Sweden.
    Kraujalyte, Z.
    European Spallat Source ERIC ESS, Sweden.
    Laloni, A.
    European Spallat Source ERIC ESS, Sweden.
    Livingston, K.
    Univ Glasgow, Scotland.
    Loehman, O.
    Tech Univ Darmstadt, Germany.
    Maulerova, V
    European Spallat Source ERIC ESS, Sweden; Lund Univ, Sweden.
    Mauritzon, N.
    European Spallat Source ERIC ESS, Sweden; Lund Univ, Sweden.
    Mueller, F.
    Forschungszentrum Julich, Germany.
    Higuera, I. Lopez
    European Spallat Source ERIC ESS, Sweden.
    Richter, T.
    European Spallat Source ERIC ESS, Sweden.
    Robinson, L.
    European Spallat Source ERIC ESS, Sweden.
    Roth, R.
    EWCON, Sweden.
    Shetty, M.
    European Spallat Source ERIC ESS, Sweden.
    Taylor, J.
    European Spallat Source ERIC ESS, Sweden.
    Woracek, R.
    European Spallat Source ERIC ESS, Sweden.
    Xiong, W.
    European Spallat Source ERIC ESS, Sweden.
    Time- and energy-resolved effects in the boron-10 based multi-grid and helium-3 based thermal neutron detectors2021Inngår i: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 32, nr 3, artikkel-id 035903Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The boron-10 based multi-grid detector is being developed as an alternative to helium-3 based neutron detectors. At the European Spallation Source, the detector will be used for time-of-flight neutron spectroscopy at cold to thermal neutron energies. The objective of this work is to investigate fine time- and energy-resolved effects of the Multi-Grid detector, down to a few mu eV, while comparing it to the performance of a typical helium-3 tube. Furthermore, it is to characterize differences between the detector technologies in terms of internal scattering, as well as the time reconstruction of similar to mu s short neutron pulses. The data were taken at the Helmholtz Zentrum Berlin, where the Multi-Grid detector and a helium-3 tube were installed at the ESS test beamline, V20. Using a Fermi-chopper, the neutron beam of the reactor was chopped into a few tens of mu s wide pulses before reaching the detector, located a few tens of cm downstream. The data of the measurements show an agreement between the derived and calculated neutron detection efficiency curve. The data also provide fine details on the effect of internal scattering, and how it can be reduced. For the first time, the chopper resolution was comparable to the timing resolution of the Multi-Grid detector. This allowed a detailed study of time- and energy resolved effects, as well as a comparison with a typical helium-3 tube.

    Fulltekst (pdf)
    fulltext
  • 28.
    Bakker, Jimmy W. P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    New methodology for optical sensing and analysis2004Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis describes the research I have done, and partly will do, during my time as a PhD student in the laboratory of Applied Optics at Linköping University. Due to circumstances beyond the scope of this book, this incorporates three quite different projects. The first two, involving gas sensing and measuring on paper with ellipsometry, have been discontinued, whereas the third one, measuring fluorescence with a computer screen and web camera, is in full progress and will be until I complete my studies.

    Thus the purpose of this work also has several aspects. Partly, it describes performed research and its results, as well as theoretical background. On the other hand, it provides practical and theoretical background necessary for future work. While the three projects are truly quite different, each of them has certain things in common with each of the other. This is certainly also true for the necessary theory. Two of them involve spectroscopic ellipsometry, for example, while another pair needs knowledge of color theory, etc. This makes it impossible to separate the projects, despite of their differences. Hopefully, these links between the different projects, connecting the different chapters, will make this work whole and consistent in its own way.

    Delarbeid
    1. Improvement of porous silicon based gas sensors by polymer modification
    Åpne denne publikasjonen i ny fane eller vindu >>Improvement of porous silicon based gas sensors by polymer modification
    2003 (engelsk)Inngår i: Physica Status Solidi (A), ISSN 0031-8965, Vol. 197, nr 2, s. 378-381Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Gas sensing was performed using spectroscopic ellipsometry and porous silicon films. Modification of the porous layer by polymer deposition showed an increase in sensitivity to organic solvent vapor of up to 135%. The increase in sensitivity is strongly dependent on polymer concentration. At high concentrations, too much polymer is deposited, presumably blocking the pores, causing a decrease in sensitivity. At sufficiently low concentrations, the polymer causes a strong increase in sensitivity. This is assumed to be caused by the polymer being deposited inside the pores, where its interaction with the vapor influences the sensitivity. At very low concentration, the sensitivity approaches values obtained without polymer modification. The sensitivity increase is different for different vapors, pointing to possible selectivity enhancement.

    Emneord
    07.07.Df, 61.43.Gt, 78.67.Bf, 82.35.Gh
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13772 (URN)10.1002/pssa.200306529 (DOI)
    Tilgjengelig fra: 2004-12-10 Laget: 2004-12-10 Sist oppdatert: 2013-10-14
    2. Determination of refractive index of printed and unprinted paper using spectroscopic ellipsometry.
    Åpne denne publikasjonen i ny fane eller vindu >>Determination of refractive index of printed and unprinted paper using spectroscopic ellipsometry.
    2004 (engelsk)Inngår i: Thin Solid Films, ISSN 0040-6090, Vol. 455-456, s. 361-365Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    An attempt is made to address the basic physical properties of printed and unprinted paper surfaces by using spectroscopic ellipsometry in the range 300–900 nm to determine the effective complex-valued refractive index N. Some simulations to address the effect of structural properties have also been done and a qualitative comparison with some other methods, in particular Brewster angle measurements, has been made. Unprinted paper and paper printed in different colors have been studied. The measured absorption properties matched the colors of the used inks well. The effects of roughness on the determined spectra of N are discussed. Simulations show that compared to other methods, like Brewster-angle reflectometry, spectroscopic ellipsometry provides a more accurate value of N, especially in wavelength regions were the color pigments show absorption.

    Emneord
    Spectroscopic ellipsometry; Paper surfaces; Optical properties; Gloss variation
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13773 (URN)10.1016/j.tsf.2004.01.024 (DOI)
    Tilgjengelig fra: 2004-12-10 Laget: 2004-12-10 Sist oppdatert: 2013-10-14
    3. Enhancing classification capabilities of computer screen photo-assisted fluorescence fingerprinting
    Åpne denne publikasjonen i ny fane eller vindu >>Enhancing classification capabilities of computer screen photo-assisted fluorescence fingerprinting
    2005 (engelsk)Inngår i: Sensors and Actuators B: Chemical, ISSN 0925-4005, Vol. 110, nr 2, s. 190-194Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The separation of emission from transmitted light for the fingerprinting of fluorescent substances using a computer screen photo-assisted technique (CSPT) is demonstrated. CSPT is a technique for optical evaluation using a simple cell with just a standard computer set and a web camera as instrumentation. It has been demonstrated to be a versatile system for colorimetric and fluorescent fingerprinting. Here the omnidirectional property of fluorescent emission is utilized to separate it from the background, using a simple optical arrangement compatible with CSPT purposes. This enhances the classification capabilities and makes classification at sub-μM concentrations possible.

    Emneord
    Computer screen photo-assisted technique; Fluorescence; Spectral fingerprinting; Bioassays; Home tests
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13774 (URN)10.1016/j.snb.2005.01.046 (DOI)
    Tilgjengelig fra: 2004-12-10 Laget: 2004-12-10 Sist oppdatert: 2009-09-08
    Fulltekst (pdf)
    FULLTEXT01
  • 29. Bestill onlineKjøp publikasjonen >>
    Bakker, Jimmy W. P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Optical Detection Using Computer Screen Photo-assisted Techniques and Ellipsometry2006Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Two main subjects, ellipsometry and computer screen photo-assisted techniques (CSPT), form the main line in this thesis. Ellipsometry is an optical technique based on the detection of polarization changes of light upon interaction with a sample. As most optical detection techniques it is non-intrusive and an additional advantage is its high surface sensitivity: thickness resolution in the order of pm can in principle be achieved. Therefore, ellipsometry is widely used as a technique for determination of optical constants and layer thickness for thin-layer structures. Lately ellipsometry has also been proposed for sensing applications, utilizing the detection of changes in the properties of thin layers. One application is described in this thesis concerning the detection of volatile organic solvents in gas phase using modified porous silicon layers, fabricated by electrochemical etching of silicon to create nm-sized pores. This greatly increases the surface area, promoting gas detection because the number of adsorption sites increases. Other applications of ellipsometry discussed in this thesis are based on combination with CSPT.

    CSPT is a way to exploit existing optical techniques for use in low-cost applications. In CSPT the computer screen itself is used as a (programmable) light source for optical measurements. For detection a web camera can be used and the whole measurement platform is formed by the computer. Since computers are available almost everywhere, this is a promising way to create optical measurement techniques for widespread use, for example in home-diagnostics. Since the only thing that needs to be added is a sample holder governing the physical or chemical process and directing the light, the cost can be kept very low. First, the use of CSPT for the measurement of fluorescence is described. Fluorescence is used in many detection applications, usually by chemically attaching a fluorescent marker molecule to a suitable species in the process and monitoring the fluorescent emission. The detection of fluorescence is shown to be possible using CSPT, first in a cuvette-based setup, then using a custom designed micro array. In the latter, polarizers were used for contrast enhancement, which in turn led to the implementation of an existing idea to test CSPT for ellipsometry measurements. In a first demonstration, involving thickness measurement of silicon dioxide on silicon, a thickness resolution in the order of nm was already achieved. After improvement of the system, gradients in protein layers could be detected, opening the door toward biosensor applications. Some further development will be needed to make the CSPT applications described here ready for the market, but the results so far are certainly promising.

    Delarbeid
    1. Improvement of porous silicon based gas sensors by polymer modification
    Åpne denne publikasjonen i ny fane eller vindu >>Improvement of porous silicon based gas sensors by polymer modification
    2003 (engelsk)Inngår i: Physica Status Solidi (A), ISSN 0031-8965, Vol. 197, nr 2, s. 378-381Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Gas sensing was performed using spectroscopic ellipsometry and porous silicon films. Modification of the porous layer by polymer deposition showed an increase in sensitivity to organic solvent vapor of up to 135%. The increase in sensitivity is strongly dependent on polymer concentration. At high concentrations, too much polymer is deposited, presumably blocking the pores, causing a decrease in sensitivity. At sufficiently low concentrations, the polymer causes a strong increase in sensitivity. This is assumed to be caused by the polymer being deposited inside the pores, where its interaction with the vapor influences the sensitivity. At very low concentration, the sensitivity approaches values obtained without polymer modification. The sensitivity increase is different for different vapors, pointing to possible selectivity enhancement.

    Emneord
    07.07.Df, 61.43.Gt, 78.67.Bf, 82.35.Gh
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13772 (URN)10.1002/pssa.200306529 (DOI)
    Tilgjengelig fra: 2004-12-10 Laget: 2004-12-10 Sist oppdatert: 2013-10-14
    2. Enhancing classification capabilities of computer screen photo-assisted fluorescence fingerprinting
    Åpne denne publikasjonen i ny fane eller vindu >>Enhancing classification capabilities of computer screen photo-assisted fluorescence fingerprinting
    2005 (engelsk)Inngår i: Sensors and Actuators B: Chemical, ISSN 0925-4005, Vol. 110, nr 2, s. 190-194Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The separation of emission from transmitted light for the fingerprinting of fluorescent substances using a computer screen photo-assisted technique (CSPT) is demonstrated. CSPT is a technique for optical evaluation using a simple cell with just a standard computer set and a web camera as instrumentation. It has been demonstrated to be a versatile system for colorimetric and fluorescent fingerprinting. Here the omnidirectional property of fluorescent emission is utilized to separate it from the background, using a simple optical arrangement compatible with CSPT purposes. This enhances the classification capabilities and makes classification at sub-μM concentrations possible.

    Emneord
    Computer screen photo-assisted technique; Fluorescence; Spectral fingerprinting; Bioassays; Home tests
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13774 (URN)10.1016/j.snb.2005.01.046 (DOI)
    Tilgjengelig fra: 2004-12-10 Laget: 2004-12-10 Sist oppdatert: 2009-09-08
    3. Two-dimensional micro array fluorescence fingerprinting with a computer screen photo-assisted technique
    Åpne denne publikasjonen i ny fane eller vindu >>Two-dimensional micro array fluorescence fingerprinting with a computer screen photo-assisted technique
    2005 (engelsk)Inngår i: Spectral Imaging: Instrumentation, Applications, and Analysis III, 2005, s. 9-15Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    Detection and classification of fluorescent dyes are demonstrated using a computer screen photo-assisted technique (CSPT). This technique has previously been demonstrated for analyzing fluorescence from 96 wells microtiterplates (200 µl per well) and from a single cuvette with some optics to enhance sensitivity. In this work a custom designed array of wells with a volume of approximately 1 mu;l is used. In order to measure such small volumes without saturating the detector, the transmitted light is masked by placing the sample between two crossed polarizers. This arrangement blocks nearly all the transmitted light, while the emitted light, which is nearly unpolarized, can still be detected. The lowest amount (concentration x volume) of analyte detectable in this setup is about 40 times smaller than in the previous setups.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13835 (URN)10.1117/12.589586 (DOI)
    Tilgjengelig fra: 2006-05-04 Laget: 2006-05-04 Sist oppdatert: 2009-04-28
    4. Computer screen photo-assisted off-null ellipsometry
    Åpne denne publikasjonen i ny fane eller vindu >>Computer screen photo-assisted off-null ellipsometry
    2006 (engelsk)Inngår i: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 45, nr 30, s. 7795-7799Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The ellipsometric measurement of thickness is demonstrated using a computer screen as a light source and a webcam as a detector, adding imaging off-null ellipsometry to the range of available computer screen photoassisted techniques. The results show good qualitative agreement with a simplified theoretical model and a thickness resolution in the nanometer range is achieved. The presented model can be used to optimize the setup for sensitivity. Since the computer screen serves as a homogeneous large area illumination source, which can be tuned to different intensities for different parts of the sample, a large sensitivity range can be obtained without sacrificing thickness resolution.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-13836 (URN)10.1364/AO.45.007795 (DOI)
    Tilgjengelig fra: 2006-05-04 Laget: 2006-05-04 Sist oppdatert: 2017-12-13
    5. Non-labeled immunodetection with a computer screen photo-assisted technique
    Åpne denne publikasjonen i ny fane eller vindu >>Non-labeled immunodetection with a computer screen photo-assisted technique
    Manuskript (Annet vitenskapelig)
    Identifikatorer
    urn:nbn:se:liu:diva-13837 (URN)
    Tilgjengelig fra: 2006-05-04 Laget: 2006-05-04 Sist oppdatert: 2010-01-13
    Fulltekst (pdf)
    FULLTEXT01
  • 30.
    Beličev, P.P.
    et al.
    University of Belgrade, Serbia.
    Gligorić, G.
    University of Belgrade, Serbia.
    Radosavljević, A.
    University of Belgrade, Serbia.
    Maluckov, A.
    University of Belgrade, Serbia.
    Stepić, M.
    University of Belgrade, Serbia.
    Johansson, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Light Localization in Nonlinear Binary Two-Dimensional Lieb Lattices2016Inngår i: Abstract Book of RIAO-OPTILAS 2016 / [ed] Moraga, P. and Saavedra, C, Concepción - Chile: CEFOP-UdeC , 2016, s. 80-80Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Light localization in photonic lattices (PLs) is a well-known phenomenon which has been investigated during decades. It has been shown that light localization in the linear regime can be achieved by designing PLs with specific geometries, instead of embedding defects or disorder in otherwise periodic lattices [1]. These geometries provide conditions necessary for destructive wave interference, leading to formation of a perfectly flat (dispersionless) energy band. Eigenvectors associated to the flat-band (FB) eigenfrequencies are entirely degenerate and compact states (FB modes) and any superposition of them is nondiffracting. One of the simplest FB lattice patterns is the two-dimensional (2D) Lieb lattice [2,3] in which the primitive cell contains three sites. By appropriate spatial repetition of this fundamental block, it is possible to achieve a FB in the energy spectrum. Light confinement in PLs can also be a consequence of the interplay between nonlinearity and diffraction when these effects cancel each other, leading to formation of solitons. Recently, it has been reported that nonlinearity and “binarism” in quasi-one-dimensional FB systems can increase the range of existence and stability of FB ring modes [4].

    We model a 2D binary Lieb lattice with nonlinearity of Kerr type and analyse numerically and analytically the existence, stability and dynamical properties of various localized modes found to emerge in spectrum. From the derived dispersion relation we found that binarism does not affect the FB. However, due to the presence of additional periodicity, new gaps occur in the energy spectrum above and below the FB and their widths depend on the ratio between coupling constants. Like in the uniform Lieb lattice, we found eigenmodes in the form of a staggered four-peak “ring” structure, but only under certain conditions which require a particular relation between the field amplitudes in neighbouring sites. In the nonlinear regime, ring modes survive in the uniform Lieb lattice but lose their stability moving away from the FB. On the other hand, nonlinearity destroys the existence of ring solutions in the binary Lieb lattice, leading to a new class of stable localized solutions which can be found in minigaps. As in previous kagome and ladder binary nonlinear strips [4], it is shown that the binarism increases the existence range of stable nonlinear localized solutions.

    References

    [1] R. A. Vicencio, M. Johansson, Physical Review A 87, 061803(R) (2013).

    [2] R. A. Vicencio et al., Physical Review Letters 114, 245503 (2015).

    [3] D. Leykam, O. Bahat-Treidel, A. S. Desyatnikov, Physical Review A 86, 031805(R) (2012).

    [4] P. P. Beličev et al., Physical Review E 92, 052916 (2015).

  • 31.
    Beličev, P.P.
    et al.
    University of Belgrade, Serbia..
    Gligorić, G.
    University of Belgrade, Serbia..
    Radosavljević, A.
    University of Belgrade, Serbia..
    Maluckov, A.
    University of Belgrade, Serbia..
    Stepić, M.
    University of Belgrade, Serbia..
    Vicencio, R.A.
    University of Chile, Chile..
    Johansson, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    On localized modes in nonlinear binary kagome ribbons2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    One of the attractive two-dimensional [2D] lattice configurations is characterized by kagome geometry. The specific arrangement of its elements, i.e. waveguides, in the form of periodic hexagons renders completely flat the first energy band in linear case. As a consequence, the localized ring-like eigenmodes belonging to the lowest energy state propagate without diffraction through the system [1, 2]. Here we study kagome ribbon [3], which can be interpreted as one-dimensional counterpart of the standard 2D kagome lattice, and can be fabricated by dint of the direct femtosecond laser inscription [4, 5].

    The existence, stability and dynamical properties of various localized modes in binary kagome ribbon with defocusing Kerr type of nonlinearity have been explored, both numerically and analytically. We derived the corresponding dispersion relation and the bandgap spectrum, confirmed the opening of mini-gaps in it and found several types of stable ring-like modes to exist: staggered, unstaggered and vortex. Beside these nonlinear mode configurations occurring in a semi-infinite gap, we investigated features of "hourglass" solutions, identified in [3] as interesting structures when kagome lattice dimensionality is reduced to 1D. In nonlinear binary kagome ribbon dynamically stable propagation of unstaggered rings, vortex modes with certain topological charge and hourglass solutions are observed, while the staggered ring solutions are destabilized. In addition, we examined possibility to generate stable propagating solitary modes inside the first mini-gap and found that these mode patterns localize within sites mutually coupled by smaller coupling constant. The last feature is opposite to the nonlinear localized solutions found in the semi-infinite gap.

    REFERENCES

    [1] R. A. Vicencio, C. Mejía-Cortés, J. Opt. 16, 015706 (2014).

    [2] R. A. Vicencio, M. Johansson, Phys. Rev. A 87, R061803 (2013).

    [3] M. Molina, Phys. Lett. A 376, 3458 (2012).

    [4] K. Davies et al., Opt. Lett. 21, 1729 (1996).

    [5] K. Itoh et al., MRS Bulletin 31, 620 (2006).

  • 32.
    Benshalom, Nimrod
    et al.
    Weizmann Inst Sci, Israel.
    Asher, Maor
    Weizmann Inst Sci, Israel.
    Jouclas, Remy
    Univ Libre Bruxelles ULB, Belgium.
    Korobko, Roman
    Weizmann Inst Sci, Israel.
    Schweicher, Guillaume
    Univ Libre Bruxelles ULB, Belgium.
    Liu, Jie
    Univ Libre Bruxelles ULB, Belgium.
    Geerts, Yves
    Univ Libre Bruxelles ULB, Belgium; Int Solvay Inst Phys & Chem, Belgium.
    Hellman, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Weizmann Inst Sci, Israel.
    Yaffe, Omer
    Weizmann Inst Sci, Israel.
    Phonon-Phonon Interactions in the Polarization Dependence of Raman Scattering2023Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 127, nr 36, s. 18099-18106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have found that the polarization dependence of Raman scattering in organic crystals at finite temperatures can only be described by a fourth-rank tensor formalism. This generalization of the second-rank Raman tensor stems from the effect of off diagonal components in the crystal self-energy on the light scattering mechanism. We thus establish a novel manifestation of phonon-phonon interaction in inelastic light scattering, markedly separate from the better-known phonon lifetime.

    Fulltekst (pdf)
    fulltext
  • 33.
    Bergström, Anna
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    SPR Sensor Surfaces based on Self-Assembled Monolayers2009Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The study and understanding of molecular interactions is fundamentally important in today's field of life sciences and there is a demand for well designed surfaces for biosensor applications. The biosensor has to be able to detect specific molecular interactions, while non-specific binding of other substances to the sensor surface should be kept to a minimum.                                                                                                                                                                                The objective of this master´s thesis was to design sensor surfaces based on self-assembled monolayers (SAMs) and evaluate their structural characteristics as well as their performance in Biacore systems. By mixing different oligo (ethylene glycol) terminated thiol compounds in the SAMs, the density of functional groups for bimolecular attachment could be controlled.  Structural characteristics of the SAMs were studied using Ellipsometry, Contact Angle Goniometry, IRAS and XPS. Surfaces showing promising results were examined further with Surface Plasmon Resonance in Biacore instruments.

    Mixed SAM surfaces with a tailored degree of functional COOH groups could be prepared. The surfaces showed promising characteristics in terms of stability, immobilization capacity of biomolecules, non-specific binding and kinetic assay performance, while further work needs to be dedicated to the improvement of their storage stability. In conclusion, the SAM based sensor surfaces studied in this thesis are interesting candidates for Biacore applications.

    Fulltekst (pdf)
    FULLTEXT02
  • 34.
    Bhatti, Muhammad Ali
    et al.
    Univ Sindh Jamshoro, Pakistan.
    Almaani, Khalida Faryal
    Univ Sindh Jamshoro, Pakistan.
    Shah, Aqeel Ahmed
    NED Univ Engn & Technol, Pakistan.
    Tahira, Aneela
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Chandio, Ali Dad
    NED Univ Engn & Technol, Pakistan.
    Mugheri, Abdul Qayoom
    Univ Sindh Jamshoro, Pakistan.
    Bhatti, Adeel liaquat
    Univ Sindh Jamshoro, Pakistan.
    Waryani, Baradi
    Univ Sindh Jamshoro, Pakistan.
    Medany, Shymaa S.
    Cairo Univ, Egypt.
    Nafady, Ayman
    King Saud Univ, Saudi Arabia.
    Ibupoto, Zafar Hussain
    Univ Sindh Jamshoro, Pakistan.
    Low Temperature Aqueous Chemical Growth Method for the Doping of W into ZnO Nanostructures and Their Photocatalytic Role in the Degradration of Methylene Blue2022Inngår i: Journal of cluster science, ISSN 1040-7278, E-ISSN 1572-8862, Vol. 33, nr 4, s. 1445-1456Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this research work, we have produced tungsten (W) doped ZnO nanostructures via low-temperature aqueous chemical growth method. The morphology, crystal arrays and composition was investigated by scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and energy dispersive X-rays (EDX) respectively. The SEM results indicate the nanowire morphology before and after the doping of W into ZnO and XRD study has shown the hexagonal crystallography of W doped ZnO samples. The EDX study has confirmed the successful doping of W into ZnO crystal lattices. The photodegradation performance of methylene blue was evaluated with W doped ZnO samples and pristine ZnO in aqueous solution. The measured degradation efficiencies for the different W doped ZnO samples were 5 wt%, 10 wt%, 15 wt% and 20 wt% at pH 5 are 87.8%, 92.3%, 92.8% and 96.9%), at pH 9 (72.1%, 90.7%, 92.1%, and 96.4%) and at pH 11 (80%, 85%, 87% and 89%) for the time interval of 90 min respectively. The pH of dye solution has significant effect on the degradation efficiency. These findings show that the W doped ZnO samples have superior degradation efficiency of 96.6% in a very short interval of time. The swift degradation kinetics for the W doped ZnO samples is attributed to the reduction in the energy band gap, decrease in particle size, enhanced surface area, decrease in the recombination rate and foster charge separation process. The obtained results are exciting and providing efficient earth-abundant photocatalysts for the energy and environmental purposes.Kindly confirm the Given names and Family names for all the authors.They are correct.

  • 35.
    Bi, Shubo
    et al.
    Shanghai Univ, Peoples R China; Sci and Technol Near Surface Detect Lab, Peoples R China.
    Wang, Chi
    Shanghai Univ, Peoples R China; Sci and Technol Near Surface Detect Lab, Peoples R China.
    Zhu, Jun
    Sci and Technol Near Surface Detect Lab, Peoples R China.
    Yuan, Zhiwen
    Sci and Technol Near Surface Detect Lab, Peoples R China.
    Yu, Yingjie
    Shanghai Univ, Peoples R China.
    Valyukh, Sergiy
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Asundi, Anand
    Nanyang Technol Univ, Singapore.
    Influence of no-core fiber on the focusing performance of an ultra-small gradient-index fiber probe2018Inngår i: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 107, s. 46-53Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The light-beam expansion effect of a no-core fiber on the focusing performance of an ultra-small gradient-index fiber probe is investigated with a view to optimizing the optical performance of such probes. By taking the variable relationship between the focusing performance (including the working distance and the focusing spot size) of the probe and the length of the no-core fiber as the criterion, the effective beam expansion length of the no-core fiber in the ultra-small gradient-index fiber probe is calculated based on the basic properties of the Gaussian beam. Verification and analysis are done by numerical calculations and experimental measurements, respectively. The obtained results show that the working distance of an ultra-small gradient-index fiber probe can be increased effectively by adding a no-core fiber; however, this will lead to increasing the focusing spot size. For the parameters of the fiber probe studied here, the effective beam expansion length of the no-core fiber spacer is less than 0.357 mm. (C) 2018 Elsevier Ltd. All rights reserved.

  • 36.
    Bil, Andrzej
    et al.
    Univ Wroclaw, Poland.
    Kochman, Michal
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska fakulteten. Univ Coll London UCL, England.
    Mierzwicki, Krzysztof
    independent researcher.
    Photoinduced double proton transfer in the glyoxal-methanol complex along T-1 reaction path - a quantum chemical topological study2021Inngår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1227, artikkel-id 129426Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The experimentally confirmed double proton transfer (DPT) reaction in glyoxal-methanol complex follows a complicated mechanism triggered by the excitation of the complex to the lowest singlet excited electronic state. The mechanism involves two complementary pathways, the first of which proceeds exclusively in the singlet manifold. The competing one, which is studied here with the use of quantum chemical topological methods, involves the lowest triplet state. Both Atoms-in-Molecules approach and Electron Localizability Indicator based approach demonstrate that protons dressed with some amount of electron density migrate to and from the methanol, which leads to the rearrangement of four covalent bonds. The transition structure nearly coincides with the dissociation of the covalent C-H bond in glyoxal. DPT proceeds through a structure formed by the protonated [MeOH2](+0.)(66), with H atoms equidistant to O atom, and deprotonated [C2O2H](-0.)(66). The key stages of the evolution of the crucial covalent bonds along the intrinsic reaction path have been demonstrated. (C) 2020 Elsevier B.V. All rights reserved.

  • 37.
    Boggio, J. M. Chavez
    et al.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Bodenmueller, D.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Ahmed, S.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Baig, A.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Hansson, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Talenti, F.
    Sapienza Univ Rome, Italy.
    Wabnitz, S.
    Sapienza Univ Rome, Italy.
    Modotto, D.
    Univ Brescia, Italy.
    Frequency comb generation in silicon nitride resonators with amplitude modulated pump2021Inngår i: LASER RESONATORS, MICRORESONATORS, AND BEAM CONTROL XXIII, SPIE-INT SOC OPTICAL ENGINEERING , 2021, Vol. 11672, artikkel-id 1167206Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate frequency comb generation in silicon nitride ring resonators by using a pump subject to a weak amplitude modulation. We show that a partial locking is obtained when the external modulation frequency differs from the resonator free-spectral-range by up to hundreds of MHz.

  • 38.
    Boggio, J. M. Chavez
    et al.
    InnoFSPEC Leibniz Inst Astrophys Potsdam, Germany.
    Bodenmüller, D.
    InnoFSPEC Leibniz Inst Astrophys Potsdam, Germany.
    Ahmed, S.
    InnoFSPEC Leibniz Inst Astrophys Potsdam, Germany.
    Wabnitz, S.
    Sapienza Univ Roma, Italy; Ist Nazl Ottica, Italy.
    Modotto, D.
    Univ Brescia, Italy.
    Hansson, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Efficient Kerr soliton comb generation in micro-resonator with interferometric back-coupling2022Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 13, nr 1, artikkel-id 1292Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nonlinear Kerr micro-resonators have enabled fundamental breakthroughs in the understanding of dissipative solitons, as well as in their application to optical frequency comb generation. However, the conversion efficiency of the pump power into a soliton frequency comb typically remains below a few percent. We fabricate and characterize a hybrid Mach-Zehnder ring resonator geometry, consisting of a micro-ring resonator embedded in an additional cavity with twice the optical path length of the ring. The resulting interferometric back coupling enables to achieve an unprecedented control of the pump depletion: pump-to-frequency comb conversion efficiencies of up to 55% of the input pump power is experimentally demonstrated with a soliton crystal comb. We assess the robustness of the proposed on-chip geometry by generating a large variety of dissipative Kerr soliton combs, which require a lower amount of pump power to be accessed, when compared with an isolated micro-ring resonator with identical parameters. Micro-resonators with feedback enable accessing new regimes of coherent soliton comb generation, and are well suited for comb applications in astronomy, spectroscopy and telecommunications. Increasing the conversion efficiency of soliton crystals will enable further application of optical frequency comb. Here the authors engineer an hybrid Mach-Zehnder micro-ring resonator to achieve 80% pump-to-comb conversion efficiency based on dissipative Kerr solitons.

    Fulltekst (pdf)
    fulltext
  • 39. Bestill onlineKjøp publikasjonen >>
    Borgh, Annika
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Biomimetic surfaces: Preparation, characterization and application2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [sv]

    I denna avhandling beskrivs tillverkning, karaktärisering och tillämpning av ett antal biomimetiska ytor. Biomimetik är att härma naturen och grundtanken är att titta på hur naturen löst liknande problemställningar. Två olika typer av modellsystem med inspiration från naturen har tagits fram för framtida tillämpningar inom bioanalys, biosensorer samt antifrysmaterial. Det ena typen av modellsystem innefattar fosforylerade ytor och det andra består av ytor som härmar antifrys(glyko)proteiner. Ytorna tillverkades av monolager av självorganiserande svavelorganiska molekyler och karaktäriserades före tillämpning med hjälp av ellipsometri, IR-spektroskopi, kontaktvinkelmätning och röntgenfotoelektronspektroskopi.

    Modellsystemen för att studera vattenfrysning på ytor inspirerades av antifrys(glyko)proteiner som bl.a. kan hittas i polarfiskar. Två modellsystem utvecklades och studerades med avseende på frysning av kondenserat vatten. Det ena designades att härma den aktiva domänen hos ett antifrysglykoproteiner (AFGP) och det andra härmade typ I antifrysproteiner (AFP I). Frysstudierna visade på signifi-kanta skillnader för AFGP-modellen jämfört med ett (OH/CH3) referenssystem med jämförbar vätbarhet, men inte för AFP Imodellen. Vattnet frös vid högre temperatur för AFGPmodellen.

    Modellsystemen med fosforylerade ytor inspirerades av fosforylering och biomineralisering. Två system utvecklades, ett med långa och ett med korta alkylkedjor på aminosyraanalogerna, både med och utan fosfatgrupp. En ny metod användes med skyddsgrupper på fosfaterna hos de långa analogerna innan bildandet av monolager. Skyddsgrupperna togs bort efter bildandet av monolager. Dessa monolager undersöktes också med elektrokemiska metoder och signifikant högre kapacitans observerades för de fosforylerade monolageren jämfört med de icke fosforylerade.

    Delarbeid
    1. A new route to the formation of biomimetic phosphate assemblies on gold: Synthesis and characterization
    Åpne denne publikasjonen i ny fane eller vindu >>A new route to the formation of biomimetic phosphate assemblies on gold: Synthesis and characterization
    Vise andre…
    2006 (engelsk)Inngår i: Journal of Colloid and Interface Science, ISSN 1095-7103, Vol. 295, nr 1, s. 41-49Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A biomimetic model system based on long-chain alkanethiols tailored with serine, threonine and tyrosine side-chain groups is created as a platform for the study of phosphorylated amino acids. The phosphorylated analogues are synthesized with protective tert-butyl groups that after assembly on thin polycrystalline gold films are removed in an acidic deprotection solution to form the corresponding phosphate self-assembled monolayers (SAMs). The SAMs are thoroughly characterized with null ellipsometry, contact angle goniometry, infrared reflection–absorption spectroscopy and X-ray photoelectron spectroscopy. The assembly and the subsequent deprotection process are optimized with respect to molecular orientation and chain conformation by varying the incubation time and the exposure time to the deprotection solution. The high quality of the generated SAMs suggests that the present assembly/deprotection approach is an attractive alternative when traditional synthetic routes become demanding because of solubility problems.

    Emneord
    SAM; Thiols; Gold; Phosphorylated amino acids; Surface deprotection scheme
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-14334 (URN)10.1016/j.jcis.2005.08.026 (DOI)
    Tilgjengelig fra: 2007-03-16 Laget: 2007-03-16 Sist oppdatert: 2021-10-13
    2. Electrochemical Evaluation of the Interfacial Capacitance upon Phosphorylation of Amino Acid Analogue Molecular Films
    Åpne denne publikasjonen i ny fane eller vindu >>Electrochemical Evaluation of the Interfacial Capacitance upon Phosphorylation of Amino Acid Analogue Molecular Films
    Vise andre…
    2001 (engelsk)Inngår i: Analytical Chemistry, ISSN 0003-2700, Vol. 73, nr 18, s. 4463-4468Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    An approach based on electrochemistry to differentiate between phosphorylated and nonphosphorylated amino acid analogues adsorbed on gold is presented. Analogues of serine, threonine, and tyrosine, containing thiohexadecyl headgroups, were synthesized and assembled on gold, and the surface capacitance was evaluated using electrochemical impedance spectroscopy. A procedure for deprotection of tert-butyl phosphate protecting groups, on the monolayer, is also described. Characterizations of the assembled analogues by cyclic voltammetry, infrared spectroscopy, and ellipsometry are used to confirm the insulating properties of the monolayers and the outcome of surface modifications. The results from cyclic voltammetry show good insulating properties for the monolayers even after phosphate deprotection. The infrared measurements reveal well-ordered monolayers, and the thickness from ellipsometry is in good agreement with expectations from molecular modeling. The impedance experiments show a capacitance increase up to 0.6 μF/cm2 as phosphate groups are introduced. The results in this study indicate the possibility of using a surface chemical and impedance spectroscopy approach to detect the kinase/phosphatase activity and kinetics involved in phosphorylation reactions.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-14335 (URN)10.1021/ac010487+ (DOI)
    Tilgjengelig fra: 2007-03-16 Laget: 2007-03-16 Sist oppdatert: 2021-09-24
    3. Synthesis and Monolayer Characterization of Phosphorylated Amino Acid Analogs
    Åpne denne publikasjonen i ny fane eller vindu >>Synthesis and Monolayer Characterization of Phosphorylated Amino Acid Analogs
    2002 (engelsk)Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 254, nr 2, s. 322-330Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The synthesis of a series of thiols containing phosphorylated and non-phosphorylated serine, threonine, and tyrosine amino acid residues is described. The synthesized molecules, based on 3-mercaptopropionic acid, were assembled onto gold and subsequently characterized using infrared reflection-absorption spectroscopy, ellipsometry, X-ray photoelectron spectroscopy, and contact angle goniometry. The ellipsometric analysis indicates that they form densely packed and well-oriented monolayers on gold, with thicknesses that are in good agreement with estimated values from space-filling models. The bulky and space-demanding phosphorylated threonine analog was, however, found to be an exception. The increase in layer thickness when adding a phosphate group to the threonine is only 35% of that observed for the two other analogs. A detailed infrared examination of the influence of cation coordination to the phosphorylated serine analog using calcium and magnesium reveals structural similarities to those of the inorganic phosphate compound calcium hydroxy apatite. We furthermore discuss the application of these monolayers as soft templates for biomineralization.

    sted, utgiver, år, opplag, sider
    Maryland Heights, MO, United States: Academic Press, 2002
    Emneord
    SAM; phosphorylated amino acid; phosphate layer; alkanethiols; gold; counterion influence
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-14336 (URN)10.1006/jcis.2002.8576 (DOI)000178935400016 ()
    Tilgjengelig fra: 2007-03-16 Laget: 2007-03-16 Sist oppdatert: 2021-09-24bibliografisk kontrollert
    4. Mimicking the properties of antifreeze glycoproteins: synthesis and characterization of a model system for ice nucleation and antifreeze studies
    Åpne denne publikasjonen i ny fane eller vindu >>Mimicking the properties of antifreeze glycoproteins: synthesis and characterization of a model system for ice nucleation and antifreeze studies
    2005 (engelsk)Inngår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, nr 33, s. 15849-15859Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Synthesis of β-D-Gal-(1 → 3)-β-D-GalNAc coupled to HOC2H4NHCOC15H30SH is described. This compound was coadsorbed at various proportions with C2H5OC2H4NHCOC15H30SH to form statistically mixed self-assembled monolayers (SAMs) on gold in an attempt to mimic the properties of the active domain in antifreeze glycoproteins (AFGPs). The monolayers were characterized by null ellipsometry, contact angle goniometry, X-ray photoelectron spectroscopy, and infrared reflection−absorption spectroscopy. The disaccharide compound adsorbed preferentially, and SAMs prepared at a solution molar ratio >0.3 displayed total wetting. The mixed SAMs showed well-organized alkyl chains up to a disaccharide surface fraction of 0.8. The amount of gauche conformers in the alkyls increased rapidly above this point, and the monolayers became disordered and less densely packed. Furthermore, the generated mixed SAMs were subjected to water vapor at constant relative humidity and the subsequent ice crystallization on a cooled substrate was monitored via an optical microscope. Interestingly, rapid crystallization occurred within a narrow range of temperatures on mixed SAMs with a high disaccharide content, surface fraction >0.3. The reported crystallization temperatures and the ice layer topography were compared with results obtained for a much simpler reference system composed of −OH/−CH3 terminated n-alkanethiols in order to account for changes in topography of the water/ice layer with surface energy. Although preliminary, the obtained results can be useful in the search for the molecular mechanism behind the antifreeze activity of AFGPs.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-14337 (URN)10.1021/jp050752l (DOI)
    Tilgjengelig fra: 2007-03-16 Laget: 2007-03-16 Sist oppdatert: 2017-12-13
    5. Biomimetic Surfaces for Ice Interaction Studies
    Åpne denne publikasjonen i ny fane eller vindu >>Biomimetic Surfaces for Ice Interaction Studies
    Manuskript (Annet vitenskapelig)
    Identifikatorer
    urn:nbn:se:liu:diva-14338 (URN)
    Tilgjengelig fra: 2007-03-16 Laget: 2007-03-16 Sist oppdatert: 2010-01-13
    Fulltekst (pdf)
    FULLTEXT01
  • 40.
    Bosma, Tom
    et al.
    Univ Groningen, Netherlands.
    Lof, Gerrit J. J.
    Univ Groningen, Netherlands.
    Gilardoni, Carmem M.
    Univ Groningen, Netherlands.
    Zwier, Olger V
    Univ Groningen, Netherlands.
    Hendriks, Freddie
    Univ Groningen, Netherlands.
    Magnusson, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. Norstel AB, Sweden.
    Ellison, Alexandre
    Norstel AB, Sweden.
    Gällström, Andreas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. Saab Dynam AB, SE-58188 Linkoping, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Nguyen, Son Tien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Havenith, Remco W. A.
    Univ Groningen, Netherlands; Univ Groningen, Netherlands; Univ Ghent, Belgium.
    van der Wal, Caspar H.
    Univ Groningen, Netherlands.
    Identification and tunable optical coherent control of transition-metal spins in silicon carbide2018Inngår i: NPJ QUANTUM INFORMATION, ISSN 2056-6387, Vol. 4, artikkel-id 48Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Color centers in wide-bandgap semiconductors are attractive systems for quantum technologies since they can combine long-coherent electronic spin and bright optical properties. Several suitable centers have been identified, most famously the nitrogen-vacancy defect in diamond. However, integration in communication technology is hindered by the fact that their optical transitions lie outside telecom wavelength bands. Several transition-metal impurities in silicon carbide do emit at and near telecom wavelengths, but knowledge about their spin and optical properties is incomplete. We present all-optical identification and coherent control of molybdenum-impurity spins in silicon carbide with transitions at near-infrared wavelengths. Our results identify spin S= 1/2 for both the electronic ground and excited state, with highly anisotropic spin properties that we apply for implementing optical control of ground-state spin coherence. Our results show optical lifetimes of similar to 60 ns and inhomogeneous spin dephasing times of similar to 0.3 mu S, establishing relevance for quantum spin-photon interfacing.

    Fulltekst (pdf)
    fulltext
  • 41.
    Bruckner, Barbara
    et al.
    Uppsala Univ, Sweden; Johannes Kepler Univ Linz, Austria.
    Hans, Marcus
    Rhein Westfal TH Aachen, Germany.
    Nyberg, Tomas
    Uppsala Univ, Sweden.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bauer, Peter
    Uppsala Univ, Sweden; Johannes Kepler Univ Linz, Austria.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Electronic excitation of transition metal nitrides by light ions with keV energies2020Inngår i: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 32, nr 40, artikkel-id 405502Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the specific electronic energy deposition by protons and He ions with keV energies in different transition metal nitrides of technological interest. Data were obtained from two different time-of-flight ion scattering setups and show excellent agreement. For protons interacting with light nitrides, i.e. TiN, VN and CrN, very similar stopping cross sections per atom were found, which coincide with literature data of N(2)gas for primary energies &lt;= 25 keV. In case of the chemically rather similar nitrides with metal constituents from the 5(th)and 6(th)period, i.e. ZrN and HfN, the electronic stopping cross sections were measured to exceed what has been observed for molecular N(2)gas. For He ions, electronic energy loss in all nitrides was found to be significantly higher compared to the equivalent data of N(2)gas. Additionally, deviations from velocity proportionality of the observed specific electronic energy loss are observed. A comparison with predictions from density functional theory for protons and He ions yields a high apparent efficiency of electronic excitations of the target for the latter projectile. These findings are considered to indicate the contributions of additional mechanisms besides electron hole pair excitations, such as electron capture and loss processes of the projectile or promotion of target electrons in atomic collisions.

  • 42.
    Börjesson, Anders
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Erdtman, Edvin
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ahlström, Peter
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berlin, Mikael
    Tetra Pak Packaging Solutions AB, Ruben Rausings gata, Lund, Sweden.
    Andersson, Thorbjörn
    Tetra Pak Packaging Solutions AB, Ruben Rausings gata, Lund, Sweden.
    Bolton, Kim
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Molecular modelling of oxygen and water permeation in polyethylene2013Inngår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 54, nr 12, s. 2988-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Monte Carlo and molecular dynamics simulations were performed to calculate solubility, S, and diffusion, D, coefficients of oxygen and water in polyethylene, and to obtain a molecular-level understanding of the diffusion mechanism. The permeation coefficient, P, was calculated from the product of S and D. The AMBER force field, which yields the correct polymer densities under the conditions studied, was used for the simulations, and it was observed that the results were not sensitive to the inclusion of atomic charges in the force field. The simulated S for oxygen and water are higher and lower than experimental data, respectively. The calculated diffusion coefficients are in good agreement with experimental data. Possible reasons for the discrepancy in the simulated and experimental solubilities, which results in discrepancies in the permeation coefficients, are discussed. The diffusion of both penetrants occurs mainly by large amplitude, infrequent jumps of the molecules through the polymer matrix.

  • 43.
    Cai, Weidong
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Kuang, Chaoyang
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Tianjun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Shang, Yuequn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Zhang, Jia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Qin, Jiajun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Multicolor light emission in manganese-based metal halide composites2022Inngår i: Applied Physics Reviews, E-ISSN 1931-9401, Vol. 9, nr 4, artikkel-id 041409Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Manganese-based organic-inorganic metal halide composites have been considered as promising candidates for lead-free emitters. However, in spite of their excellent luminescence properties in green and red regions, blue emission-a critical component for white light generation-from pristine manganese-based composites is currently missing. In this work, we successfully achieve blue luminescence center in manganese-based composites through selecting specific organic component methylbenzylamine (MBA). Our approach is fundamentally different from green and red emission in manganese-based composites, which result from manganese-halide frameworks. The coexistence of different luminescence centers in our manganese-based composites is confirmed by photoluminescence (PL) and photoluminescence excitation (PLE) results. As a result of different photoluminescence excitation responses of different emission centers, the resulting emission color can be tuned with selecting different excitation wavelengths. Specifically, a white light emission can be obtained with Commission Internationale de leclairage coordinates of (0.33, 0.35) upon the 330 nm excitation. We further demonstrate the promise of our manganese-based composites in the anti-counterfeiting technology and multicolor lighting. Our results provide a novel strategy for full-spectral emission in manganese-based organic-inorganic metal halide composites and lay a solid foundation for a range of new applications. (C) 2022 Author(s).

    Fulltekst (pdf)
    fulltext
  • 44.
    Caporaletti, Francesca
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten. Univ Mons UMONS, Belgium; Inst Laue Langevin LSS, France.
    Rubio-Magnieto, Jenifer
    Univ Mons UMONS, Belgium; Univ Jaume 1, Spain.
    Lo, Mamadou
    Univ Montpellier, France; Univ Assane Seck Ziguinchor, Senegal.
    Longevial, Jean-Francois
    Univ Montpellier, France.
    Rose, Clemence
    Univ Montpellier, France.
    Clement, Sebastien
    Univ Montpellier, France.
    van der Lee, Arie
    Univ Montpellier, France.
    Surin, Mathieu
    Univ Mons UMONS, Belgium.
    Richeter, Sebastien
    Univ Montpellier, France.
    Design of metalloporphyrins fused to imidazolium rings for binding DNA G-quadruplexes2020Inngår i: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 24, nr 1-3, s. 340-349Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Synthesis and characterization of nickel(II) meso-tetraarylporphyrins fused to imidazolium rings across beta,beta-pyrrolic positions and X-ray structure of the porphyrin where two opposed pyrrole units are fused to an imidazolium ring are presented. The interactions between these mono-, bis-, tris- and tetrakis(imidazolium) porphyrins with human telomeric DNA G-quadruplexes (G4) were investigated using UV-vis absorption spectroscopy, Circular Dichroism (CD) spectroscopy and Fluorescence Resonance Energy Transfer (FRET) melting assay. Possible binding modes between cationic porphyrins and a selected G4 sequence (d[AG(3)(T(2)AG(3))(3)]), and relative stabilities of porphyrin/G4 complexes are discussed. Excepting porphyrins fused to one imidazolium ring, the other derivatives interact with G4 structures and their stabilization strongly depends on the porphyrin structure (number and localization of the imidazolium rings).

  • 45.
    Carlsson, Adam
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Phase stability and mechanical properties of M4AlB4 (m=Cr, Hf, Mo, Nb, Ta, Ti, V, W, Zr) from first principles2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The recent discovery of Cr4AlB4, a laminated ternary metal boride belonging to the family of layered MAB-phases, where the transition metal boride layers are interleaved by an A layer, has spurred theoretical investigation for novel M4AlB4 phases. In this study, first-principles calculations were applied in order to investigate the thermodynamical stability and mechanical properties of M4AB4 where M = Cr, Hf, Mo, Nb, Ta, Ti, V, W, Zr while the A layer was kept fixed as Al. The thermodynamical stability calculations validate the recently discovered Cr4AlB4 phase’s stability and suggest the neighboring phase Mo4AlB4 to be stable. Additionally, the phases Mo3AlB4, Mo2AlB2, Ti4AlB4 and Ti2AlB2 indicates phases close to stable with a formation enthalpy within the range of 0 < ∆H < 25 meV per atom compared to competing phases. Hence dynamical stability investigations were carried out, which indicates Mo4AlB4 to be dynamically stable. The stability of Mo4AlB4 does encourage synthesizing attempts to be kept in mind as a future project. Phase stability trends of the 111, 212, 314 and 414 compositions were discovered, where a 212, 314 and 414 composition is seen to be more stable for an M-element with lower electron configuration. Furthermore, the mechanical properties of the 414 compositions were investigated by systematically straining the unit cell in different directions. The bulk-, shear- and Young’s-modulus were derived and are presented, where Ti4AlB4 demonstrates values similar to the commended Ti2AlC MAX-phase. Finally, ductility plots are presented which purposes a linear trend between the elements of group IV, V and VI. Based on the results, further studies with a focus on the temperature and magnetization’s impact on the stability and mechanical properties are suggested.

    Fulltekst (pdf)
    fulltext
  • 46. Bestill onlineKjøp publikasjonen >>
    Carlsson, Andreas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten. Swedish National Forens Centre NFC, Linkoping, Sweden.
    Synthesis and spectroscopic characterization of emerging synthetic cannabinoids and cathinones2016Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The application of different analytical techniques is fundamental in forensic drug analysis. In the wake of the occurrence of large numbers of new psychoactive substances possessing similar chemical structures as already known ones, focus has been placed on applied criteria for their univocal identification. These criteria vary, obviously, depending on the applied technique and analytical approach. However, when two or more substances are proven to have similar analytical properties, these criteria no longer apply, which imply that complementary techniques have to be used in their differentiation.

    This work describes the synthesis of some structural analogues to synthetic cannabinoids and cathinones based on the evolving patterns in the illicit drug market. Six synthetic cannabinoids and six synthetic cathinones were synthesized, that, at the time for this study, were not as yet found in drug seizures. Further, a selection of their spectroscopic data is compared to those of already existing analogues; mainly isomers and homologues. The applied techniques were mass spectrometry (MS), Fourier transformed infrared (FTIR, gas phase) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. In total, 59 different compounds were analyzed with the  selected techniques.

    The results from comparison of spectroscopic data showed that isomeric substances may in some cases be difficult to unambiguously identify based only on their GC-MS EI spectra. On the other hand, GC-FTIR demonstrated more distinguishable spectra. The spectra for the homologous compounds showed however, that the GC-FTIR technique was less successful compared to GC-MS. Also a pronounced fragmentation pattern for some of the cathinones was found.

    In conclusion, this thesis highlights the importance of using complementary techniques for the univocal identification of synthetic cannabinoids and cathinones. By increasing the number of analogues investigated, the more may be learnt about the capabilities of different techniques for structural differentiations, and thereby providing important identification criteria leading to trustworthy forensic evidence.

    Delarbeid
    1. Prediction of designer drugs: synthesis and spectroscopic analysis of synthetic cannabinoid analogues of 1H-indol-3-yl(2,2,3,3-tetramethylcyclopropyl) methanone and 1H-indol-3-yl(adamantan-1-yl)methanone
    Åpne denne publikasjonen i ny fane eller vindu >>Prediction of designer drugs: synthesis and spectroscopic analysis of synthetic cannabinoid analogues of 1H-indol-3-yl(2,2,3,3-tetramethylcyclopropyl) methanone and 1H-indol-3-yl(adamantan-1-yl)methanone
    Vise andre…
    2016 (engelsk)Inngår i: Drug Testing and Analysis, ISSN 1942-7603, E-ISSN 1942-7611, Vol. 8, nr 10, s. 1015-1029Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this work, emergence patterns of synthetic cannabinoids were utilized in an attempt to predict those that may appear on the drug market in the future. Based on this information, two base structures of the synthetic cannabinoid analogues - (1H-indol-3-yl (2,2,3,3-tetramethylcyclopropyl) methanone and 1H-indol-3-yl(adamantan-1-yl)methanone) - together with three substituents butyl, 4-fluorobutyl and ethyl tetrahydropyran - were selected for synthesis. This resulted in a total of six synthetic cannabinoid analogues that to the authors knowledge have not yet appeared on the drug market. Spectroscopic data, including nuclearmagnetic resonance (NMR), mass spectrometry (MS), and Fourier transforminfrared (FTIR) spectroscopy (solid and gas phase), are presented for the synthesized analogues and some additional related cannabinoids. In this context, the suitability of the employed techniques for the identification of unknowns is discussed and the use of GC-FTIR as a secondary complementary technique to GC-MS is addressed. Examples of compounds that are difficult to differentiate by their mass spectra, but can be distinguished based upon their gas phase FTIR spectra are presented. Conversely, structural homologueswhere mass spectra aremore powerful than gas phase FTIR spectra for unambiguous assignments are also exemplified. This work further emphasizes that a combination of several techniques is the key to success in structural elucidations. Copyright (C) 2015 John Wiley amp; Sons, Ltd.

    sted, utgiver, år, opplag, sider
    WILEY-BLACKWELL, 2016
    Emneord
    drug analysis; proactive; synthetic cannabinoids; synthesis; mass spectrometry
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132473 (URN)10.1002/dta.1904 (DOI)000384806400003 ()26526273 (PubMedID)
    Merknad

    Funding Agencies|Swedish Contingencies Agency (MSB)

    Tilgjengelig fra: 2016-11-13 Laget: 2016-11-12 Sist oppdatert: 2018-01-13
    Fulltekst (pdf)
    Synthesis and spectroscopic characterization of emerging synthetic cannabinoids and cathinones
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  • 47.
    Chamizo, E.
    et al.
    Univ Seville, Spain.
    López Lora, Mercedes
    Linköpings universitet, Institutionen för hälsa, medicin och vård, Avdelningen för diagnostik och specialistmedicin. Linköpings universitet, Medicinska fakulteten. Univ Seville, Spain.
    Christl, M.
    Swiss Fed Inst Technol, Switzerland.
    Performance of the 1 MV Accelerator Mass Spectrometry system at the Centro Nacional de Aceleradores for the analysis of U-233 at environmental levels2022Inngår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 533, s. 81-89Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    U-233 (T-1/2 = 0.159 My) has aroused much interest in the last few years because of the potential of U-233/U-236 to inform about anthropogenic U sources. The reported U-233/U-238 atom ratios in general environmental samples are in the 10(-12)-10(-6) range. We demonstrate that U-233/U-238 abundance sensitivities at the 5 x 10(-11) level can be achieved at the 1 MV Accelerator Mass Spectrometry system at the Centro Nacional de Aceleradores (CNA, Seville, Spain). Unresolved U-234, U-235 and Th-232 molecular fragments are identified as the main U-233 background contributors and procedures to subtract them are proposed. U-233/U-238 and U-236/U-238 atom ratios were analysed in the IAEA reference materials coded Soil-6, 300, 385, 410, and 412 at the CNA and at the 600 kV ETH AMS system for intercomparison. U-233/U-238 atom ratios for samples 412 and 385 were only reported by the ETH.

  • 48.
    Chang, Lin
    et al.
    Shanghai Univ, Peoples R China.
    Valyukh, Sergiy
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    He, Tingting
    Shanghai Univ, Peoples R China.
    Chen, Zhu
    Shanghai Univ, Peoples R China.
    Yu, Yingjie
    Shanghai Univ, Peoples R China.
    Multi-surface phase-shifting algorithm using the window function fitted by the nonlinear least squares method2022Inngår i: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 69, nr 3, s. 160-171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multi-surface phase demodulation algorithm is proposed to measure surfaces of the transparent plate simultaneously. A non-linear least-squares method based on the trust region is utilized to fit the window function derived from the characteristic polynomials. The fitted window function requires fewer parameters and has a flexible form, which means the window length can be stretched freely and used flexibly. Then, a multi-surface phase demodulation technique combining the discrete Fourier principle and the fitted window function is investigated, allowing simultaneous reconstruction of the measured front surface, rear surface, and thickness variation. During the implementation of our algorithm, the processing time for the interferograms with 850x850 pixels is around 5.1s. Measurement errors caused by several factors are analyzed, including wavelength-tuning error, frequency order error, cavity length error, and average thickness error. The experimental result on a rectangular transparent plate further verifies the effectiveness of our algorithm.

  • 49.
    Charalambidis, Georgios
    et al.
    University of Crete, Greece.
    Georgilis, Evangelos
    University of Crete, Greece; Fdn Research and Technology Hellas FORTH, Greece.
    Panda, Manas K.
    University of Crete, Greece; CSIR NIIST, India.
    Anson, Christopher E.
    Karlsruhe Institute Technology, Germany.
    Powell, Annie K.
    Karlsruhe Institute Technology, Germany; Karlsruhe Institute Technology, Germany.
    Doyle, Stephen
    Karlsruhe Institute Technology, Germany; Karlsruhe Institute Technology, Germany.
    Moss, David
    Karlsruhe Institute Technology, Germany; Karlsruhe Institute Technology, Germany.
    Jochum, Tobias
    Karlsruhe Institute Technology, Germany; Karlsruhe Institute Technology, Germany; Abcr GmbH, Germany.
    Horton, Peter N.
    University of Southampton, England.
    Coles, Simon J.
    University of Southampton, England.
    Linares, Mathieu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska fakulteten.
    Beljonne, David
    University of Mons UMONS, Belgium; University of Mons UMONS, Belgium.
    Naubron, Jean-Valere
    Aix Marseille University, France.
    Conradt, Jonas
    Karlsruhe Institute Technology, Germany; Karlsruhe Institute Technology, Germany.
    Kalt, Heinz
    Karlsruhe Institute Technology, Germany; Karlsruhe Institute Technology, Germany.
    Mitraki, Anna
    University of Crete, Greece; Fdn Research and Technology Hellas FORTH, Greece.
    Coutsolelos, Athanassios G.
    University of Crete, Greece.
    Silviu Balaban, Teodor
    Aix Marseille University, France.
    A switchable self-assembling and disassembling chiral system based on a porphyrin-substituted phenylalanine-phenylalanine motif2016Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 7, nr 12657Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Artificial light-harvesting systems have until now not been able to self-assemble into structures with a large photon capture cross-section that upon a stimulus reversibly can switch into an inactive state. Here we describe a simple and robust FLFL-dipeptide construct to which a meso-tetraphenylporphyrin has been appended and which self-assembles to fibrils, platelets or nanospheres depending on the solvent composition. The fibrils, functioning as quenched antennas, give intense excitonic couplets in the electronic circular dichroism spectra which are mirror imaged if the unnatural FDFD-analogue is used. By slightly increasing the solvent polarity, these light-harvesting fibres disassemble to spherical structures with silent electronic circular dichroism spectra but which fluoresce. Upon further dilution with the nonpolar solvent, the intense Cotton effects are recovered, thus proving a reversible switching. A single crystal X-ray structure shows a head-to-head arrangement of porphyrins that explains both their excitonic coupling and quenched fluorescence.

    Fulltekst (pdf)
    fulltext
  • 50.
    Chateau, Denis
    et al.
    Laboratoire de Chimie, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1.
    Liotta, Adrien
    Laboratoire de Chimie, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1.
    Lundén, Hampus
    Electrooptical Systems, Swedish Defence Research Agency (FOI).
    Lerouge, Frederic
    Laboratoire de Chimie, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1.
    Chaput, Frederic
    Laboratoire de Chimie, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1.
    Krein, Douglas
    Air Force Research Laboratory.
    Cooper, Thomas
    Air Force Research Laboratory.
    Lopes, Cesar
    Electrooptical Systems, Swedish Defence Research Agency (FOI).
    El-Amay, Ali A. G.
    Department on Physics, Norwegian University of Science and Technology.
    Lindgren, Mikael
    Department on Physics, Norwegian University of Science and Technology.
    Parola, Stephane
    Laboratoire de Chimie, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1.
    Long Distance Enhancement of Nonlinear Optical Properties Using Low Concentration of Plasmonic Nanostructures in Dye Doped Monolithic Sol-Gel Materials.2016Inngår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, nr 33, s. 10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Monolithic sol-gel silica composites incorporating platinum-based chromophores and various types of gold nanoparticles (AuNPs) are prepared and polished to high optical quality. Their photophysical properties are investigated. The glass materials show well-defined localized surface plasmon resonance (SPR) absorbance from the visible to NIR. No redshifts of the AuNP plasmon absorption peaks due to the increase in nanoparticle doping concentration are observed in the glasses, proving that no or very small SPR coupling effects occur between the AuNPs. At 600 nm excitation, but not at 532 nm, the AuNPs improve the nonlinear absorption performance of glasses codoped with 50 × 10−3 m of a Pt-acetylide chromophore. The glasses doped with lower concentrations of AuNPs (2-5 μm average distance) and 50 × 10−3 m in chromophore, show a marked improvement in nonlinear absorption, with no or only small improvement for the more highly AuNP doped glasses. This study shows the importance of excitation wavelength and nanoparticle concentration for composite systems employing AuNPs to improve two-photon absorption of chromophores. [ABSTRACT FROM AUTHOR]

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