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  • 1.
    A. Sani, Negar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik.
    M-PSK and M-QAM Modulation/Demodulation of UWB Signal Using Six-Port Correlator2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays high speed and high data rate communication are highly demanded. Consequently, wideband and high frequency transmitter and receivers should be designed. New transmitters and receivers should also have low power consumption, simple design and low manufacturing price in order to fulfill manufacturers’ requests for mass production. Having all above specifications, six-port correlator is a proper choice to be used as modulator and demodulator in transmitters and receivers.

    In this thesis the six-port correlator is introduced, modeled and simulated using Advanced Design System (ADS) software. A simple six-port transmitter/receiver system with a line of sight link is modeled and analyzed in BER, path length and noise terms. The modulation in this system is QAM, frequency is 7.5 GHz and symbol rate is 500 Msymbol/s.

    Furthermore two methods are proposed for high frequency and high symbol rate M-PSK and M-QAM modulation using six-port correlator. The 7.5 GHz modulators are modeled and simulated in ADS. Data streams generated by pseudo random bit generator with 1 GHz bandwidth are applied to modulators. Common source field effect transistors (FETs) with zero bias are used as controllable impedance termination to apply baseband data to modulator. Both modulators show good performance in M-PSK and M-QAM modulation.

    Fulltekst (pdf)
    FULLTEXT01
  • 2.
    Aaboen, Lise
    et al.
    Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Fredriksson, Anna
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    The relationship development aspect of production transfer2016Inngår i: Journal of Purchasing and Supply Management, ISSN 1478-4092, E-ISSN 1873-6505, Vol. 22, nr 1, s. 53-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Production transfers are a result of outsourcing and offshoring decisions. Because of the strategic focus of the outsourcing literature, the operational issues of relationship development between sender and receiver and its impact on the transfer progress have not been fully depicted. The purpose of the present paper is to explore relationship development during production transfer. To fulfil this purpose, we studied three different production transfers and derived four propositions for further testing. Our main conclusions included that dependence and power gradually shift between the sender and the receiver and that the relationship between them sets the arena for what types of relationships can be developed between the receiver and the suppliers. Furthermore, short social distances can bridge cultural and technological distances to some extent, because it motivates the actors to bring their relationship into a more developed state. Finally, we noticed that the headquarters’ involvement can work both as an inhibitor as well as a converter.

    Fulltekst (pdf)
    fulltext
  • 3.
    Aarao, J
    et al.
    University of South Australia.
    Bradshaw-Hajek, B H
    University of South Australia.
    Miklavcic, Stan
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ward, D A
    University of South Australia.
    Numerical implementation of the EDEM for modified Helmholtz BVPs on annular domains2011Inngår i: JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS, ISSN 0377-0427, Vol. 235, nr 5, s. 1342-1353Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a recent paper by the current authors a new methodology called the Extended-Domain-Eigenfunction-Method (EDEM) was proposed for solving elliptic boundary value problems on annular-like domains. In this paper we present and investigate one possible numerical algorithm to implement the EDEM. This algorithm is used to solve modified Helmholtz BVPs on annular-like domains. Two examples of annular-like domains are studied. The results and performance are compared with those of the well-known boundary element method (BEM). The high accuracy of the EDEM solutions and the superior efficiency of the EDEM over the BEM, make EDEM an excellent alternate candidate to use in the animation industry, where speed is a predominant requirement, and by the scientific community where accuracy is the paramount objective.

  • 4.
    Aarao, J
    et al.
    University of South Australia.
    Bradshaw-Hajek, B H
    University of South Australia.
    Miklavcic, Stan
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ward, D A
    University of South Australia.
    The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains2010Inngår i: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, ISSN 1751-8113, Vol. 43, nr 18, s. 185202-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Standard analytical solutions to elliptic boundary value problems on asymmetric domains are rarely, if ever, obtainable. In this paper, we propose a solution technique wherein we embed the original domain into one with simple boundaries where the classical eigenfunction solution approach can be used. The solution in the larger domain, when restricted to the original domain, is then the solution of the original boundary value problem. We call this the extended-domain-eigenfunction method. To illustrate the methods strength and scope, we apply it to Laplaces equation on an annular-like domain.

  • 5.
    Aarao, J
    et al.
    University of S Australia, Australia .
    Miklavcic, Stan J.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ward, D A.
    University of S Australia, Australia .
    Extended-domain-eigenfunction method (EDEM): a study of ill posedness and regularization2013Inngår i: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 46, nr 8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The extended-domain-eigenfunction method (EDEM) proposed for solving elliptic boundary value problems on annular-like domains requires an inversion process. The procedure thus represents an ill-posed problem, whose numerical solution involves an ill-conditioned system of equations. In this paper, the ill-posed nature of EDEM is studied and numerical solutions based on regularization schemes are considered. It is shown that the EDEM solution methodology lends itself naturally to a formulation in terms of the well-known iterative Landweber method and the more general and faster converging semi-iterative regularization schemes. Theoretical details and numerical results of the regularization schemes are presented for the case of the two-dimensional Laplace operator on annular domains.

  • 6.
    Aasheim, Fanny
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Gestsson, Linnea
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Det spelar ingen roll hur du gör det - bara du gör det: Hur ett koncept kan utformas för att uppmana till motion utan att bidra till hälsohets2020Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 7.
    Aav, Sebastian
    Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Adaptive Music System for DirectSound2005Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the intention of surveying the field of research in adaptive audio systems for interactive media, a suggested audio system design for adaptive music control is described, and a prototype implementation of key parts of the system is presented and evaluated.

    Foregoing midi-triggered sound banks, the proposed design uses layered segmented audio files, defined and controlled by XML-scripts. The results demonstrate an inclination of a flexible system, capable of adequate adaptive behaviour of high quality sound.

    The implemented system will serve as an extensive basis for future work contributing to the research of adaptive behaviour to both music and sound effects for interactive media, and also as a preliminary foray into the more experimental field of stand-alone non-linear music playback.

    Fulltekst (pdf)
    FULLTEXT01
  • 8.
    Aban, Kevin
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Göst, Jens
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Analysis of transports with pharmaceuticals on Arlanda airport2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Rapporten syftar till att kartlägga och analysera dagens transportflöde av läkemedel på fraktområdet Cargo City på Arlanda. Cargo Center och APH Logistics är två fraktagenter som har sin verksamhet på Cargo City. Observera att Cargo City och Cargo Center inte har samma innebörd. Cargo Center och APH Logistics erbjuder genom nära samarbete transport och hantering av temperaturkänsligt gods, som till exempel läkemedel. Läkemedel är värdefullt gods som kräver särskild skötsel vid transport, hantering och förvaring. Det ställer stränga krav på samtliga aktörer i försörjningskedjan. Genom studiebesök och intervjuer har författarna kartlagt det befintliga flödet av läkemedel. SACT, ett åkeri och dotterbolag till Cargo Center, utför transporten av godset till Cargo City med nerkylda lastbilar. APH Logistics omlastningsterminal på Cargo City är temperaturkontrollerad, vilket innebär att läkemedelsgodset förvaras och lastats i flygcontainrar där. Det färdiglastade godset forslas sedan vidare till Cargo Centers terminal. Där sker vikt- och volymkontroll av godset, det registreras i olika datasystem och slutligen märks det med etiketter, så som flygfraktsedeln. Mycket av godset som hanteras på Arlanda körs med lastbil till andra flygplatser och destinationer runt om i Europa istället för att flygfraktas direkt från flygplatsen. Dessutom hanteras och förvaras inte allt läkemedelsgods under temperaturkontrollerade former. En totalkostnadsanalys har gjorts för att jämföra olika transportflödesscenarion. Dessutom har författarna identifierat den kundservice Cargo Center och APH Logistics bör erbjuda kunden. Den bygger på kvalitativa resonemang. Resultatet av rapporten är författarnas rekommendation till företagen av hur de bör gå tillväga i framtiden. Den ger både kortsiktiga och långsiktiga tips.

    Fulltekst (pdf)
    fulltext
  • 9.
    Abarkan, Myriam
    et al.
    Univ Bordeaux, France.
    Pirog, Antoine
    Univ Bordeaux, France.
    Mafilaza, Donnie
    Univ Bordeaux, France.
    Pathak, Gaurav
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. MOC, France.
    NKaoua, Gilles
    Univ Bordeaux, France.
    Puginier, Emilie
    Univ Bordeaux, France.
    OConnor, Rodney
    MOC, France.
    Raoux, Matthieu
    Univ Bordeaux, France.
    Donahue, Mary
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. MOC, France.
    Renaud, Sylvie
    Univ Bordeaux, France.
    Lang, Jochen
    Univ Bordeaux, France.
    Vertical Organic Electrochemical Transistors and Electronics for Low Amplitude Micro-Organ Signals2022Inngår i: Advanced Science, E-ISSN 2198-3844, Vol. 9, nr 8, artikkel-id 2105211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification. Vertical PEDOT:PSS-based OECTs (vOECTs) further enhance signal amplification and device density but have not been characterized in biological applications. An electronic board with individually tuneable transistor biases overcomes fabrication induced heterogeneity in device metrics and allows quantitative biological experiments. Careful exploration of vOECT electric parameters defines voltage biases compatible with reliable transistor function in biological experiments and provides useful maximal transconductance values without influencing cellular signal generation or propagation. This permits successful application in monitoring micro-organs of prime importance in diabetes, the endocrine pancreatic islets, which are known for their far smaller signal amplitudes as compared to neurons or heart cells. Moreover, vOECTs capture their single-cell action potentials and multicellular slow potentials reflecting micro-organ organizations as well as their modulation by the physiological stimulator glucose. This opens the possibility to use OECTs in new biomedical fields well beyond their classical applications.

    Fulltekst (pdf)
    fulltext
  • 10.
    Abbas, Malik Waseem
    et al.
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Soomro, Razium Ali
    Natl Inst Biotechnol and Genet Engn, Pakistan; Univ Sindh, Pakistan; Univ Bristol, England.
    Kalwar, Nazar Hussain
    Shah Abdul Latif Univ, Pakistan.
    Zahoor, Mehvish
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Avci, Ahmet
    Selcuk Univ, Turkey.
    Pehlivan, Erol
    Selcuk Univ, Turkey.
    Hallam, Keith Richard
    Univ Bristol, England.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Carbon quantum dot coated Fe3O4 hybrid composites for sensitive electrochemical detection of uric acid2019Inngår i: Microchemical journal (Print), ISSN 0026-265X, E-ISSN 1095-9149, Vol. 146, s. 517-524Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The study explores carbon quantum dots (C-dots) as potential candidates for enhancing the signal sensitivity of an electrochemical sensor devised for biologically important molecule, such as uric acid (UA). The C-dots were evaluated for their electrochemical characteristics in combination with Fe3O4 nanoparticles (Fe3O4 NPs), which were applied as the primary electro-catalytic promoter. The hybrid nanocomposite (C-dots/Fe3O4 HCs) formation was achieved by facilitating the adsorption of C-dots over Fe3O4 NPs using amine-carbonyl interactions. Unlike, one pot method, the proposed strategy enables aggregation-free coverage of Fe3O4 NPs with highly conductive layer of C-dots that can act as conduction centres to support ultra-fast electron transfer kinetics to satisfy the need of high signal sensitivity. The hybrid composite demonstrated remarkable signal improvement when tested against the electrochemical oxidation of UA. The heighten current response and lower over-potential values enabled development of a DC-amperometric (DC-AMP) sensor for UA with a linear working range of 0.01 to 0.145 mu M and signal sensitivity measurable up to 6.0 x 10(-9) M. The said improvement was manifested as a synergetic outcome of active redox couple (Fe (III/II)), larger surface area of Fe3O4 NPs engulfed with a layer of highly conductive C-dots acting as efficient charge sensitisers.

  • 11.
    Abbas, Zaheer
    et al.
    Beijing Univ Chem Technol, Peoples R China.
    Soomro, Razium Ali
    Beijing Univ Chem Technol, Peoples R China; Beijing Univ Chem Technol, Peoples R China.
    Kalwar, Nazar Hussain
    Shah Abdul Latif Univ Khairpur, Pakistan.
    Tunesi, Mawada
    Beijing Univ Chem Technol, Peoples R China.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Karakus, Selcan
    Istanbul Univ Cerrahpa Avcilar, Turkey.
    Kilislioglu, Ayben
    Istanbul Univ Cerrahpa Avcilar, Turkey.
    In Situ Growth of CuWO4 Nanospheres over Graphene Oxide for Photoelectrochemical (PEC) Immunosensing of Clinical Biomarker2020Inngår i: Sensors, E-ISSN 1424-8220, SENSORS, Vol. 20, nr 1, artikkel-id 148Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Procalcitonin (PCT) protein has recently been identified as a clinical marker for bacterial infections based on its better sepsis sensitivity. Thus, an increased level of PCT could be linked with disease diagnosis and therapeutics. In this study, we describe the construction of the photoelectrochemical (PEC) PCT immunosensing platform based on it situ grown photo-active CuWO4 nanospheres over reduced graphene oxide layers (CuWO4@rGO). The in situ growth strategy enabled the formation of small nanospheres (diameter of 200 nm), primarily composed of tiny self-assembled CuWO4 nanoparticles (2-5 nm). The synergic coupling of CuWO4 with rGO layers constructed an excellent photo-active heterojunction for photoelectrochemical (PEC) sensing. The platform was then considered for electrocatalytic (EC) mechanism-based detection of PCT, where inhibition of the photocatalytic oxidation signal of ascorbic acid (AA), subsequent to the antibody-antigen interaction, was recorded as the primary signal response. This inhibition detection approach enabled sensitive detection of PCT in a concentration range of 10 pgmL(-1) to 50 ng.mL(-1) with signal sensitivity achievable up to 0.15 pgmL(-1). The proposed PEC hybrid (CuWO4@rGO) could further be engineered to detect other clinically important species.

    Fulltekst (pdf)
    fulltext
  • 12.
    Abbasi, Mazhar Ali
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    The synthesis, characterization and device fabrication of ZnO, NiO and their composite nanostructures2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Electronics industry has been revolutionized since last few decades because of the fabrication of electronic devices by using nanoscale based materials. But the more innovative feature in the electronic devices is the use of transparent materials, which makes the transparent electronic devices as one of the most interesting research field in nanoscience and nano-technology now a days. In order to have high performance electronic devices based on the wide band gap compound semiconductors, a selection of right transparent material is crucial step. Among all the transparent metal oxides, ZnO is one of the potential candidates due to the ease in the synthesis process, wide bandgap of 3.37 eV, a high exciton binding energy of 60 meV and diverse morphologies. Since p-type ZnO based nanodevices are still difficult to fabricate due to the instability and unreliability of p-type ZnO nanomaterial, therefore several p-type semiconductors are used for the development of p-n junctions. Among those NiO is suitable p-type compound semiconductor to make p-n junction with ZnO because of its wide band gap of 3.7 eV and environment friendly conditions for its synthesis. Keeping these attractive properties of n-type ZnO and p-type NiO, the synthesis of composite nanostructures of these two transparent oxides and fabrication of their electronic devices is presented in this dissertation work.

    I started my work with the synthesis of ZnO nanostructures focusing on the effect of different anions of zinc salts on the morphology and crystallinity of ZnO nanostructures. Then I grow honey-comb like NiO nanostructures on 3D nickel foam and used these nanostructures for the detection of Zinc ion. After that synthesized NiO and ZnO based composite nanostructures and characterized them, having main focus on the luminescence properties of ZnO when decorated with NiO nanostructures. The composite nanostructures of p-type NiO and n-type ZnO showed enhancement in the luminescence properties. Since pn junction is the back bone of electronic devices so working on the designing of band alignment along with the current transport properties of p-type NiO/n-type ZnO composite structures, an attempt was put forwarded to explain the phenomenon of these compound semiconducting materials. Different devices based on these two compound semiconducting materials are fabricated and designed in the present dissertation work, however still more work is required to improve the efficiency of devices like LEDs and UV detectors.

    Delarbeid
    1. Anions effect on the low temperature growth of ZnO nanostructures
    Åpne denne publikasjonen i ny fane eller vindu >>Anions effect on the low temperature growth of ZnO nanostructures
    Vise andre…
    2012 (engelsk)Inngår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 86, nr 12, s. 1998-2001Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Seed mediated aqueous chemical growth (ACG) route was used for the growth of ZnO nanostructures on Si substrate in four different growth mediums. The growth medium has shown to affect the morphology and the size of the different nanostructures. We observed that the medium containing zinc nitrate anions yields the nanorods, in a medium containing zinc acetate anions nano-candles are obtained. While in a medium containing zinc chloride anions ZnO nano-discs were obtained and in a medium containing zinc sulfate anions nano-flakes are achieved. Growth in these different mediums has also shown effect on the optical emission characteristics of the different ZnO nanostructures.

    sted, utgiver, år, opplag, sider
    Elsevier, 2012
    Emneord
    ZnO, Chemical growth, Nanostructures, Optical properties
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-84909 (URN)10.1016/j.vacuum.2012.05.020 (DOI)000308672000041 ()
    Tilgjengelig fra: 2012-10-26 Laget: 2012-10-26 Sist oppdatert: 2024-01-08
    2. Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures
    Åpne denne publikasjonen i ny fane eller vindu >>Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures
    Vise andre…
    2012 (engelsk)Inngår i: Sensors, E-ISSN 1424-8220, Vol. 12, nr 11, s. 15424-15437Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

    sted, utgiver, år, opplag, sider
    MDPI, 2012
    Emneord
    honeycomb NiO nanostructures, potentiometric response, ion selective electrode, selectivity, selective ionophore
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-86653 (URN)10.3390/s121115424 (DOI)000311429500060 ()
    Tilgjengelig fra: 2012-12-20 Laget: 2012-12-20 Sist oppdatert: 2024-01-08
    3. Decoration of ZnO nanorods with coral reefs like NiO nanostructures by the hydrothermal growth method and their luminescence study
    Åpne denne publikasjonen i ny fane eller vindu >>Decoration of ZnO nanorods with coral reefs like NiO nanostructures by the hydrothermal growth method and their luminescence study
    Vise andre…
    2014 (engelsk)Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 7, nr 1, s. 430-440Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Composite nanostructures of coral reefs like p-type NiO on n-type ZnO nanorods have been decorate on fluorine-doped tin oxide glass substrates by the hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy,  high-resolution transmission electron microscopy and X-ray diffraction techniques. This investigation has shown that the adopted synthesis has led to high crystalline quality nanostructures. Morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL) spectra for the synthesized composite nanostructures were dominated by a near band gap emission at 380 nm and by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence originates mainly from the ZnO nanorods.

    sted, utgiver, år, opplag, sider
    MDPI, 2014
    Emneord
    ZnO nanorods; NiO nanostructure; composite nanostructures; defect states; cathodoluminescent
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-103339 (URN)10.3390/ma7010430 (DOI)000336088500030 ()
    Tilgjengelig fra: 2014-01-17 Laget: 2014-01-17 Sist oppdatert: 2024-01-08bibliografisk kontrollert
    4. The determination of valence band offset and the current transport properties of the p-NiO/n-ZnO heterojunction
    Åpne denne publikasjonen i ny fane eller vindu >>The determination of valence band offset and the current transport properties of the p-NiO/n-ZnO heterojunction
    Vise andre…
    2013 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The electron transport in the electronic devices has significant influence on the device performance, thus current transport properties determination is highly demanded for a particular device. Herein, we report the facile hydrothermal growth method based fabrication of p-NiO/n-ZnO heterojunction. The material characterization was performed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and X-ray photo electron spectroscopy. These techniques provided the good crystal quality, pure phase of p-NiO and n-ZnO nanostructures respectively. The measured valance band offset of composite nanostructure is 2.25 eV and conduction band offset was found to be 2.58 eV. The current transport properties of the fabricated p-n junction are governed by three different I-V regions. The impedance spectroscopy was used for the determination of the role of grain boundaries at the interface.

    Emneord
    Zinc oxide, nickel oxide, heterojunction, diode, current transport properties
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-103340 (URN)
    Tilgjengelig fra: 2014-01-17 Laget: 2014-01-17 Sist oppdatert: 2024-01-08bibliografisk kontrollert
    5. Fabrication of UV photo-detector based on coral reef like p-NiO/n-ZnO nanocomposite structures
    Åpne denne publikasjonen i ny fane eller vindu >>Fabrication of UV photo-detector based on coral reef like p-NiO/n-ZnO nanocomposite structures
    Vise andre…
    2013 (engelsk)Inngår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 108, s. 149-152Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this research work, a UV photo-detector is fabricated on fluorine doped tin oxide (FTO) glass substrate by exploiting the advantageous features of p-n heterojunctions based on p-NiO and n-ZnO composite nanostructures forming a coral-reef like structures. Scanning electron microscopy (SEM) and X-ray diffraction results showed uniform morphology and good crystal quality of the synthesised nanostructures respectively. I-V measurements have shown nonlinear and rectifying response of the p-NiO/n-ZnO heterojunction. The proposed photodiode exhibited excellent UV response with acceptable photocurrent generation of about 3.4 mA and the responsivity of 2.27 A/W at -3 biasing voltage.

    sted, utgiver, år, opplag, sider
    Elsevier, 2013
    Emneord
    p-NiO/n-ZnO composite nanostructures, Photodiode, UV-visible spectrophotometry
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-99403 (URN)10.1016/j.matlet.2013.06.083 (DOI)000324562900038 ()
    Tilgjengelig fra: 2013-10-17 Laget: 2013-10-17 Sist oppdatert: 2024-01-08
    6. The fabrication of white light-emitting diodes using the n-ZnO/NiO/p-GaN heterojunction with enhanced luminescence
    Åpne denne publikasjonen i ny fane eller vindu >>The fabrication of white light-emitting diodes using the n-ZnO/NiO/p-GaN heterojunction with enhanced luminescence
    Vise andre…
    2013 (engelsk)Inngår i: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 8, nr 320Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cheap and efficient white light-emitting diodes (LEDs) are of great interest due to the energy crisis all over the world. Herein, we have developed heterojunction LEDs based on the well-aligned ZnO nanorods and nanotubes on the p-type GaN with the insertion of the NiO buffer layer that showed enhancement in the light emission. Scanning electron microscopy have well demonstrated the arrays of the ZnO nanorods and the proper etching into the nanotubes. X-ray diffraction study describes the wurtzite crystal structure array of ZnO nanorods with the involvement of GaN at the (002) peak. The cathodoluminescence spectra represent strong and broad visible emission peaks compared to the UV emission and a weak peak at 425 nm which is originated from GaN. Electroluminescence study has shown highly improved luminescence response for the LEDs fabricated with NiO buffer layer compared to that without NiO layer. Introducing a sandwich-thin layer of NiO between the n-type ZnO and the p-type GaN will possibly block the injection of electrons from the ZnO to the GaN. Moreover, the presence of NiO buffer layer might create the confinement effect.

    Emneord
    White light-emitting diode; ZnO nanorods; Nanotubes; NiO buffer layer
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-103341 (URN)10.1186/1556-276X-8-320 (DOI)000331642900001 ()
    Tilgjengelig fra: 2014-01-17 Laget: 2014-01-17 Sist oppdatert: 2024-01-08bibliografisk kontrollert
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    omslag
  • 13.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Hussain, Mushtaque
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    The fabrication of white light-emitting diodes using the n-ZnO/NiO/p-GaN heterojunction with enhanced luminescence2013Inngår i: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 8, nr 320Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cheap and efficient white light-emitting diodes (LEDs) are of great interest due to the energy crisis all over the world. Herein, we have developed heterojunction LEDs based on the well-aligned ZnO nanorods and nanotubes on the p-type GaN with the insertion of the NiO buffer layer that showed enhancement in the light emission. Scanning electron microscopy have well demonstrated the arrays of the ZnO nanorods and the proper etching into the nanotubes. X-ray diffraction study describes the wurtzite crystal structure array of ZnO nanorods with the involvement of GaN at the (002) peak. The cathodoluminescence spectra represent strong and broad visible emission peaks compared to the UV emission and a weak peak at 425 nm which is originated from GaN. Electroluminescence study has shown highly improved luminescence response for the LEDs fabricated with NiO buffer layer compared to that without NiO layer. Introducing a sandwich-thin layer of NiO between the n-type ZnO and the p-type GaN will possibly block the injection of electrons from the ZnO to the GaN. Moreover, the presence of NiO buffer layer might create the confinement effect.

    Fulltekst (pdf)
    fulltext
  • 14.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Hussain, Mushtaque
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Pozina, Galia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Decoration of ZnO nanorods with coral reefs like NiO nanostructures by the hydrothermal growth method and their luminescence study2014Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 7, nr 1, s. 430-440Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Composite nanostructures of coral reefs like p-type NiO on n-type ZnO nanorods have been decorate on fluorine-doped tin oxide glass substrates by the hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy,  high-resolution transmission electron microscopy and X-ray diffraction techniques. This investigation has shown that the adopted synthesis has led to high crystalline quality nanostructures. Morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL) spectra for the synthesized composite nanostructures were dominated by a near band gap emission at 380 nm and by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence originates mainly from the ZnO nanorods.

    Fulltekst (pdf)
    fulltext
  • 15.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Khan, Azam
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fabrication of UV photo-detector based on coral reef like p-NiO/n-ZnO nanocomposite structures2013Inngår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 108, s. 149-152Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this research work, a UV photo-detector is fabricated on fluorine doped tin oxide (FTO) glass substrate by exploiting the advantageous features of p-n heterojunctions based on p-NiO and n-ZnO composite nanostructures forming a coral-reef like structures. Scanning electron microscopy (SEM) and X-ray diffraction results showed uniform morphology and good crystal quality of the synthesised nanostructures respectively. I-V measurements have shown nonlinear and rectifying response of the p-NiO/n-ZnO heterojunction. The proposed photodiode exhibited excellent UV response with acceptable photocurrent generation of about 3.4 mA and the responsivity of 2.27 A/W at -3 biasing voltage.

  • 16.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Hussain Ibupoto, Zafar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Khan, Yaqoob
    National Centre for Physics, Islamabad, Pakistan .
    Khan, Azam
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Iron (III) Ion Sensor Based on the Seedless Grown ZnO Nanorods in 3 Dimensions Using Nickel Foam Substrate2013Inngår i: Journal of Sensors, ISSN 1687-725X, E-ISSN 1687-7268, nr 382726Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, the seedless, highly aligned and vertical ZnO nanorods in 3 dimensions (3D) were grown on the nickel foam substrate. The seedless grown ZnO nanorods were characterised by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) techniques. The characterised seedless ZnO nanorods in 3D on nickel foam were highly dense, perpendicular to substrate, grown along the (002) crystal plane, and also composed of single crystal. In addition to this, these seedless ZnO nanorods were functionalized with trans-dinitro-dibenzo-18-6 crown ether, a selective iron (III) ion ionophore, along with other components of membrane composition such as polyvinyl chloride (PVC), 2-nitopentylphenyl ether as plasticizer (NPPE), and tetrabutyl ammonium tetraphenylborate (TBATPB) as conductivity increaser. The sensor electrode has shown high linearity with a wide range of detection of iron (III) ion concentrations from 0.005 mM to 100 mM. The low limit of detection of the proposed ion selective electrode was found to be 0.001 mM. The proposed sensor also described high storage stability, selectivity, reproducibility, and repeatability and a quick response time of less than 10 s.

    Fulltekst (pdf)
    fulltext
  • 17.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ibupoto, Zafar Hussain
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Hussain, Mushtaque
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Khan, Yaqoob
    Quaid-e-Azam University Campus, Islamabad, Pakistan.
    Khan, Azam
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures2012Inngår i: Sensors, E-ISSN 1424-8220, Vol. 12, nr 11, s. 15424-15437Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

    Fulltekst (pdf)
    fulltext
  • 18.
    Abbasi, Mazhar Ali
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Khan, Yaqoob
    National Centre for Physics, Quaid-e-Azam University Campus, Islamabad, Pakistan .
    Hussain, Sajjad
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Anions effect on the low temperature growth of ZnO nanostructures2012Inngår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 86, nr 12, s. 1998-2001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Seed mediated aqueous chemical growth (ACG) route was used for the growth of ZnO nanostructures on Si substrate in four different growth mediums. The growth medium has shown to affect the morphology and the size of the different nanostructures. We observed that the medium containing zinc nitrate anions yields the nanorods, in a medium containing zinc acetate anions nano-candles are obtained. While in a medium containing zinc chloride anions ZnO nano-discs were obtained and in a medium containing zinc sulfate anions nano-flakes are achieved. Growth in these different mediums has also shown effect on the optical emission characteristics of the different ZnO nanostructures.

    Fulltekst (pdf)
    fulltext
  • 19.
    Abbasi, Muneeb Mehmood
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Jabbar, Mohammad Abdul
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Design and Performance Analysis of Low-Noise Amplifier with Band-Pass Filter for 2.4-2.5 GHz2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Low power wireless electronics is becoming more popular due to durability, portability and small dimension. Especially, electronic devices in instruments, scientific and medical (ISM) band is convenient from the spectrum regulations and technology availability point of view. In the communication engineering society, to make a robust transceiver is always a matter of challenges for the better performance.

    However, in this thesis work, a new approach of design and performance analysis of Low-Noise Amplifier with Band-Pass filter is performed at 2.45 GHz under the communication electronics research group of Institute of Science and Technology (ITN). Band-Pass Filtered Low-Noise Amplifier is designed with lumped components and transmission lines. Performances of different designs are compared with respect to noise figure, gain, input and output reflection coefficient. In the design process, a single stage LNA is designed with amplifier, ATF-58143. Maximally flat band-pass (BPF) filters were designed with lumped components and distributed elements. Afterwards, BPF is integrated with the LNA at the front side of LNA to get a compact Band-Pass Filtered Low-Noise Amplifier with good performance.

    Advanced Design System (ADS) tool was used for design and simulation, and each design was tuned to get the optimum value for noise figure, gain and input reflection coefficient. LNA stand-alone gives acceptable value of noise figure and gain but the bandwidth was too wide compared to specification. Band-Pass Filtered Low-Noise Amplifier with lumped components gives also considerable values of noise and gain. But the gain was not so flat and the bandwidth was also wide. Then, Band-Pass Filtered Low-Noise Amplifier was designed with transmission lines where the optimum value of noise figure and gain was found. The gain was almost flat over the whole band, i.e., 2.4-2.5 GHz compared to LNA stand-alone and Band-Pass Filtered Low-Noise Amplifier designed with lumped components. It is observed that deviations of results from schematic to layout level are considerable, i.e., electromagnetic simulation is needed to predict the Band-Pass Filtered Low-Noise Amplifier performance.

    Prototype of LNA, Band-Pass Filtered Low-Noise Amplifier with lumped and transmission lines are made at ITN’s PCB laboratory. Due to unavailability of exact values of Murata components and for some other technical reasons, the measured values of Band-Pass Filtered Low-Noise Amplifier with lumped components and transmission lines are deviated compared to predicted values from simulation.

    Fulltekst (pdf)
    fulltext
  • 20.
    Abbasy, Leila
    et al.
    Tabriz University of Medical Sciences, Iran.
    Mohammadzadeh, Arezoo
    Tabriz University of Medical Sciences, Iran.
    Hasanzadeh, Mohammad
    Tabriz University of Medical Sciences, Iran.
    Razmi, Nasrin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Development of a reliable bioanalytical method based on prostate specific antigen trapping on the cavity of molecular imprinted polymer towards sensing of PSA using binding affinity of PSA-MIP receptor: A novel biosensor2020Inngår i: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 188, artikkel-id 113447Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, electrically-conducting poly [Toluidine Blue (PTB)] was applied as artificial receptor. It was organized by molecular imprinting approaches and via electrochemical technique for the sensitive monitoring of prostate-specific antigen (PSA). The protein-imprinted PTB was electropolymerized in a pre-formed glutaraldehyde-cysteamine (GA-Cys A) matrix on the surface of gold electrode, which significantly boosted the stability against degradation of the Molecular Imprinted Polymer (MIP) on the surface of pre-modified gold electrode. Moreover, the MIP bio-receptor ability towards protein recognition was explored by some electrochemical techniques. The binding affinity of MIP system was considerably upper than that of non-imprinted polymer (NIP) system, indicating the success of the method in generating imprinted materials that was specifically use to PSA protein. The incubation of the MIP modified electrode in various concentration of PSA (from 1-60 μg/L) resulted in the increase of the Fe (CN)63-/4- redox peak current. The bio-device also showed linear response from 1-60 μg/L and LLOQ of 1 μg/L by using DPV technique, leading to PSA monitoring in clinical samples. The proposed MIP-based biosensor was satisfactorily applied to the determination of PSA in human plasma samples. Therefore, the developed bio-device provides a new approach for sensitive, simple, rapid, and cost-effective monitoring of 1 μg/L of PSA. Notably, this approach could appear as an appropriate candidate for point-of-care (POC) use in clinical and biomedical analyses.

  • 21.
    Abdala, Esraa
    et al.
    Department of Chemical Engineering, University of Khartoum, Khartoum, Sudan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Mustafa, Mustafa A.
    Materials and Nanotechnology Research Centre, University of Khartoum, Khartoum, Sudan.
    Efficient Biodiesel Production from Algae Oil Using Ca-Doped ZnO Nanocatalyst2020Inngår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 59, nr 43, s. 19235-19243Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biodiesel is a sustainable alternative to petroleum diesel produced by transesterification of vegetable oils in the presence of a catalyst. The present study investigates heterogeneous transesterification of algal oil to biodiesel using novel calcium-doped zinc oxide nanocatalysts synthesized using a UV shaker. The developed catalyst was under different light sources, UV and non-UV; different calcium concentrations (0.01, 0.03, 0.05 M); and different calcination temperatures (600, 700, 800 degrees C). The catalyst has been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and energy-dispersive spectroscopy (EDS). The effects of the different parameters used in catalyst preparation were studied for transesterification of algal oil. The catalyst of 0.05 M calcium loading and 700 degrees C calcination temperature synthesized in UV light is considered as the most suitable nanocatalyst, which achieved 99.18% yield of biodiesel. The catalyst was used three times effectively with 76% yield. The chemical properties of biodiesel have been investigated using gas chromatography (GC).

    Fulltekst (pdf)
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  • 22.
    Abdalla, Hassan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Fabiano, Simone
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Kemerink, Martijn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Investigation of the dimensionality of charge transport in organic field effect transistors2017Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 95, nr 8, artikkel-id 85301Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ever since the first experimental investigations of organic field effect transistors (OFETs) the dimensionality of charge transport has alternately been described as two dimensional (2D) and three dimensional (3D). More recently, researchers have turned to an analytical analysis of the temperature-dependent transfer characteristics to classify the dimensionality as either 2D or 3D as well as to determine the disorder of the system, thereby greatly simplifying dimensionality investigations. We applied said analytical analysis to the experimental results of our OFETs comprising molecularly well-defined polymeric layers as the active material as well as to results obtained from kinetic Monte Carlo simulations and found that it was not able to correctly distinguish between 2D and 3D transports or give meaningful values for the disorder and should only be used for quasiquantitative and comparative analysis. We conclude to show that the dimensionality of charge transport in OFETs is a function of the interplay between transistor physics and morphology of the organic material.

    Fulltekst (pdf)
    fulltext
  • 23.
    Abdel Aziz, Ilaria
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. Univ Basque Country UPV EHU, Spain.
    Gladisch, Johannes
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Griggs, Sophie
    Univ Oxford, England.
    Moser, Maximilian
    Univ Oxford, England.
    Biesmans, Hanne
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Beloqui, Ana
    Univ Basque Country UPV EHU, Spain; Basque Fdn Sci, Spain.
    McCulloch, Iain
    Univ Oxford, England.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Stavrinidou, Eleni
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Drug delivery via a 3D electro-swellable conjugated polymer hydrogel2024Inngår i: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Spatiotemporal controlled drug delivery minimizes side-effects and enables therapies that require specific dosing patterns. Conjugated polymers (CP) can be used for electrically controlled drug delivery; however so far, most demonstrations were limited to molecules up to 500 Da. Larger molecules could be incorporated only during the CP polymerization and thus limited to a single delivery. This work harnesses the record volume changes of a glycolated polythiophene p(g3T2) for controlled drug delivery. p(g3T2) undergoes reversible volumetric changes of up to 300% during electrochemical doping, forming pores in the nm-size range, resulting in a conducting hydrogel. p(g3T2)-coated 3D carbon sponges enable controlled loading and release of molecules spanning molecular weights of 800-6000 Da, from simple dyes up to the hormone insulin. Molecules are loaded as a combination of electrostatic interactions with the charged polymer backbone and physical entrapment in the porous matrix. Smaller molecules leak out of the polymer while larger ones could not be loaded effectively. Finally, this work shows the temporally patterned release of molecules with molecular weight of 1300 Da and multiple reloading and release cycles without affecting the on/off ratio.

  • 24.
    Abdel Aziz, Ilaria
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Gladisch, Johannes
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Musumeci, Chiara
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Moser, Maximilian
    Univ Oxford, England.
    Griggs, Sophie
    Univ Oxford, England.
    Kousseff, Christina J.
    Univ Oxford, England.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Mcculloch, Iain
    Univ Oxford, England.
    Stavrinidou, Eleni
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Electrochemical modulation of mechanical properties of glycolated polythiophenes2024Inngår i: Materials Horizons, ISSN 2051-6347, E-ISSN 2051-6355Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical doping of organic mixed ionic-electronic conductors is key for modulating their conductivity, charge storage and volume enabling high performing bioelectronic devices such as recording and stimulating electrodes, transistors-based sensors and actuators. However, electrochemical doping has not been explored to the same extent for modulating the mechanical properties of OMIECs on demand. Here, we report a qualitative and quantitative study on how the mechanical properties of a glycolated polythiophene, p(g3T2), change in situ during electrochemical doping and de-doping. The Young's modulus of p(g3T2) changes from 69 MPa in the dry state to less than 10 MPa in the hydrated state and then further decreases down to 0.4 MPa when electrochemically doped. With electrochemical doping-dedoping the Young's modulus of p(g3T2) changes by more than one order of magnitude reversibly, representing the largest modulation reported for an OMIEC. Furthermore, we show that the electrolyte concentration affects the magnitude of the change, demonstrating that in less concentrated electrolytes more water is driven into the film due to osmosis and therefore the film becomes softer. Finally, we find that the oligo ethylene glycol side chain functionality, specifically the length and asymmetry, affects the extent of modulation. Our findings show that glycolated polythiophenes are promising materials for mechanical actuators with a tunable modulus similar to the range of biological tissues, thus opening a pathway for new mechanostimulation devices. This work investigates the changes in the mechanical properties of glycolated polythiophenes induced by electrochemical addressing and by electrolyte concentration, due to its ability to stabilize water.

  • 25.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Dhillon, Harpreet S.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    A Reinforcement Learning Framework for Optimizing Age of Information in RF-Powered Communication Systems2020Inngår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 68, nr 8, s. 4747-4760Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we study a real-time monitoring system in which multiple source nodes are responsible for sending update packets to a common destination node in order to maintain the freshness of information at the destination. Since it may not always be feasible to replace or recharge batteries in all source nodes, we consider that the nodes are powered through wireless energy transfer (WET) by the destination. For this system setup, we investigate the optimal online sampling policy (referred to as the age-optimal policy) that jointly optimizes WET and scheduling of update packet transmissions with the objective of minimizing the long-term average weighted sum of Age of Information (AoI) values for different physical processes (observed by the source nodes) at the destination node, referred to as the sum-AoI. To solve this optimization problem, we first model this setup as an average cost Markov decision process (MDP) with finite state and action spaces. Due to the extreme curse of dimensionality in the state space of the formulated MDP, classical reinforcement learning algorithms are no longer applicable to our problem even for reasonable-scale settings. Motivated by this, we propose a deep reinforcement learning (DRL) algorithm that can learn the age-optimal policy in a computationally-efficient manner. We further characterize the structural properties of the age-optimal policy analytically, and demonstrate that it has a threshold-based structure with respect to the AoI values for different processes. We extend our analysis to characterize the structural properties of the policy that maximizes average throughput for our system setup, referred to as the throughput-optimal policy. Afterwards, we analytically demonstrate that the structures of the age-optimal and throughput-optimal policies are different. We also numerically demonstrate these structures as well as the impact of system design parameters on the optimal achievable average weighted sum-AoI.

    Fulltekst (pdf)
    fulltext
  • 26.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Dhillon, Harpreet S.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    AoI-Optimal Joint Sampling and Updating for Wireless Powered Communication Systems2020Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 69, nr 11, s. 14110-14115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper characterizes the structure of the Age of Information (AoI)-optimal policy in wireless powered communication systems while accounting for the time and energy costs of generating status updates at the source nodes. In particular, for a single source-destination pair in which a radio frequency (RF)-powered source sends status updates about some physical process to a destination node, we minimize the long-term average AoI at the destination node. The problem is modeled as an average cost Markov Decision Process (MDP) in which, the generation times of status updates at the source, the transmissions of status updates from the source to the destination, and the wireless energy transfer (WET) are jointly optimized. After proving the monotonicity property of the value function associated with the MDP, we analytically demonstrate that the AoI-optimal policy has a threshold-based structure w.r.t. the state variables. Our numerical results verify the analytical findings and reveal the impact of state variables on the structure of the AoI-optimal policy. Our results also demonstrate the impact of system design parameters on the optimal achievable average AoI as well as the superiority of our proposed joint sampling and updating policy w.r.t. the generate-at-will policy.

    Fulltekst (pdf)
    fulltext
  • 27.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Dhillon, Harpreet S.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Online Age-minimal Sampling Policy for RF-powered IoT Networks2019Inngår i: 2019 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM), IEEE , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we study a real-time Internet of Things (IoT)-enabled monitoring system in which a source node (e.g., IoT device or an aggregator located near a group of IoT devices) is responsible for maintaining the freshness of information status at a destination node by sending update packets. Since it may not always be feasible to replace or recharge batteries in all IoT devices, we consider that the source node is powered by wireless energy transfer (WET) by the destination. For this system setup, we investigate the optimal online sampling policy that minimizes the long-term average Age-of-Information (AoI), referred to as the age-optimal policy. The age-optimal policy determines whether each slot should be allocated for WET or update packet transmission while considering the dynamics of battery level, AoI, and channel state information (CSI). To solve this optimization problem, we model this setup as an average cost Markov Decision Process (MDP). After analytically establishing the monotonicity property of the value function associated with the MDP, the age-optimal policy is proven to be a threshold based policy with respect to each of the system state variables. We extend our analysis to characterize the structural properties of the policy that maximizes average throughput for our system setup, referred to as the throughput-optimal policy. Afterwards, we analytically demonstrate that the structures of the age optimal and throughput-optimal policies are different. We also numerically demonstrate these structures as well as the impact of system design parameters on the optimal achievable average AoI.

  • 28.
    Abd-Elmagid, Mohamed A.
    et al.
    Virginia Tech, VA 24061 USA.
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Dhillon, Arpreet S.
    Virginia Tech, VA 24061 USA.
    On the Role of Age of Information in the Internet of Things2019Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 57, nr 12, s. 72-77Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we provide an accessible introduction to the emerging idea of Age of Information (AoI) that quantifies freshness of information and explore its possible role in the efficient design of freshness-aware Internet of Things (IoT). We start by summarizing the concept of AoI and its variants with emphasis on the differences between AoI and other well-known performance metrics in the literature, such as throughput and delay. Building on this, we explore freshness-aware IoT design for a network in which IoT devices sense potentially different physical processes and are supposed to frequently update the status of these processes at a destination node (e.g., a cellular base station). Inspired by recent interest, we also assume that these IoT devices are powered by wireless energy transfer by the destination node. For this setting, we investigate the optimal sampling policy that jointly optimizes wireless energy transfer and scheduling of update packet transmissions from IoT devices with the goal of minimizing long-term weighted sum-AoI. Using this, we characterize the achievable AoI region. We also compare this AoI-optimal policy with the one that maximizes average throughput (throughput-optimal policy), and demonstrate the impact of system state on their structures. Several promising directions for future research are also presented.

    Fulltekst (pdf)
    fulltext
  • 29.
    Abdollahi Sani, Negar
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Mirbel, Deborah
    Univ Bordeaux, France.
    Fabiano, Simone
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Simon, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Brochon, Cyril
    Univ Bordeaux, France.
    Cloutet, Eric
    Univ Bordeaux, France.
    Hadziioannou, Georges
    Univ Bordeaux, France.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    A ferroelectric polymer introduces addressability in electrophoretic display cells2019Inngår i: FLEXIBLE AND PRINTED ELECTRONICS, ISSN 2058-8585, Vol. 4, nr 3, artikkel-id 035004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During the last decades, tremendous efforts have been carried out to develop flexible electronics for a vast array of applications. Among all different applications investigated in this area, flexible displays have gained significant attention, being a vital part of large-area devices, portable systems and electronic labels etc electrophoretic (EP) ink displays have outstanding properties such as a superior optical switch contrast and low power consumption, besides being compatible with flexible electronics. However, the EP ink technology requires an active matrix-addressing scheme to enable exclusive addressing of individual pixels. EP ink pixels cannot be incorporated in low cost and easily manufactured passive matrix circuits due to the lack of threshold voltage and nonlinearity, necessities to provide addressability. Here, we suggest a simple method to introduce nonlinearity and threshold voltage in EP ink display cells in order to make them passively addressable. Our method exploits the nonlinearity of an organic ferroelectric capacitor that introduces passive addressability in display cells. The organic ferroelectric material poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) is here chosen because of its simple manufacturing protocol and good polarizability. We demonstrate that a nonlinear EP cell with bistable states can be produced by depositing a P(VDF-TrFE) film on the bottom electrode of the display cell. The P(VDF-TrFE) capacitor and the EP ink cell are separately characterized in order to match the surface charge at their respective interfaces and to achieve and optimize bistable operation of display pixels.

    Fulltekst (pdf)
    fulltext
  • 30.
    Abdollahi Sani, Negar
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Robertsson, Mats
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Cooper, Philip
    De La Rue Plc, Overton, Hampshire, UK .
    Wang, Xin
    Acreo AB, Norrköping, Sweden.
    Svensson, Magnus
    Acreo AB, Norrköping, Sweden.
    Andersson Ersman, Peter
    Acreo AB, Norrköping, Sweden.
    Norberg, Petronella
    Acreo AB, Norrköping, Sweden.
    Nilsson, Marie
    Acreo AB, Norrköping, Sweden.
    Nilsson, David
    Acreo AB, Norrköping, Sweden.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Hesselbom, Hjalmar
    Hesselbom Innovation and Development HB, Huddinge, Sweden .
    Akesso, Laurent
    De La Rue Plc, Overton, Hampshire, UK .
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan. Acreo AB, Norrköping, Sweden.
    Gustafsson, Goran
    Acreo AB, Norrköping, Sweden.
    All-printed diode operating at 1.6 GHz2014Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 111, nr 33, s. 11943-11948Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications.

    Fulltekst (pdf)
    fulltext
  • 31.
    Abdollahi Sani, Negar
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Wang, Xin
    Acreo Swedish ICT AB, Sweden.
    Granberg, Hjalmar
    INNVENTIA AB, Sweden.
    Andersson Ersman, Peter
    Acreo Swedish ICT AB, Sweden.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Dyreklev, Peter
    Acreo Swedish ICT AB, Sweden.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Gustafsson, Göran
    Acreo Swedish ICT AB, Sweden.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose2016Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 6, nr 28921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future "internet of things" viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-mu Ps) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-mu Ps and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-mu Ps. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm(2), a current rectification ratio up to 4 x 10(3) between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

    Fulltekst (pdf)
    fulltext
  • 32.
    Abdul Aziz Hasan Ali, Aamir
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Shahzad, Muhammad Adil
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    A Joint Subcarrier/Power allocation Scheme for OFDMA-based Cellular Networks2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The assignment of this master thesis consists of initiating power, subcarrier allocation in a dynamic FFR based scheme designed for multi-cell OFDMA networks and to enhance the throughput of all center users in bandwidth hungry borrower cells (overloaded cells) which was previously degraded by original FFR3 scheme as a result of partitioning of system bandwidth into center and edge bands respectively. The method uses band borrowing to compensate center user’s throughput loss in a semi and fully overloaded system. The scheme uses dynamic programming method (0/1 knapsack problem) to bargain an edge band on various power levels and tends to check the best combination (power and sub-carrier) which the system can utilize while still maintaining acceptable throughput loss for the users at the edge of the neighboring cell (lender cell).

    The algorithm consists of generating a borrowing request to neighboring cells for utilizing their edge bands by the overloaded borrower cell if their average center user throughput reaches below a minimum threshold value set in the system. The borrowing method uses 0/1 knapsack problem to capture an edge band based on limiting factors of total cost in average throughput losses by neighbors (Ci) and Un (tolerable mean user edge user throughput loss by lending cell). While solving knapsack problem the lender (neighbors) will check Ci and Un before granting the right to use its edge band. The later stage requires reducing subcarrier power level in order to utilize the lenders edge band using "soft borrower" mode. The borrowed sub-carriers will be activated take power from the original center band sub-carriers of the overloaded cell by taking into account the interference between the lender and the borrower. In case of negative (0) reply from the lender cell after the first request, multiple requests are generated at reduce power level at every step to order to acquire more bands. If a neighbor has band borrowing requests from multiple overloaded base stations, the band will be granted to the one which gives minimal loss in terms of throughput to the lender cell.

    The simulation results are analyzed w.r.t reuse-1 and FFR3 scheme of a multi cell regular and irregular scenarios comprising of lightly to heavily overloaded cells with various subcarrier allocation patterns. An overhead and time assessment is also presented between borrower and lender cells. Simulation results show an increase of 60% in center user’s throughput w.r.t original FFR3 scheme with an acceptable loss of 18% at the edges in complex overloaded scenarios while the overall system throughout increases by 35%.

    Fulltekst (pdf)
    fulltext
  • 33.
    Abdul Nazar, Mohamed
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Design of a Gysel Combiner at 100 MHz2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis relates to the design and implementation of a Gysel power combiner consisting of two input ports. The design is implemented using discrete (lumped) components over the conventional transmission line architecture and operates at 100 MHz. Because of the high power requirements for the power combiner, special attention is given to the power handling capabilities of the lumped elements and the other components involved. Simulations of an S-parameter of Gysel power combiner are performed using the Advanced Design System (ADS) from Keysight Technologies. The final design of two-way Gysel power combiner using PCB toroidal inductor was implemented, simulated and optimized at centre frequency of 100 MHz. Satisfactory results were obtained in terms of Insertion loss, Return loss and Port Isolation.

    Fulltekst (pdf)
    Design of a Gysel Combiner at 100 MHz
  • 34.
    Abdullaeva, Oliya
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Sahalianov, Ihor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Silverå Ejneby, Malin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Jakesova, Marie
    Brno Univ Technol, Czech Republic.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Liin, Sara
    Linköpings universitet, Institutionen för biomedicinska och kliniska vetenskaper, Avdelningen för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Glowacki, Eric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. Brno Univ Technol, Czech Republic.
    Faradaic Pixels for Precise Hydrogen Peroxide Delivery to Control M-Type Voltage-Gated Potassium Channels2022Inngår i: Advanced Science, E-ISSN 2198-3844, Vol. 9, nr 3, artikkel-id 2103132Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    H2O2 plays a significant role in a range of physiological processes where it performs vital tasks in redox signaling. The sensitivity of many biological pathways to H2O2 opens up a unique direction in the development of bioelectronics devices to control levels of reactive-oxygen species (ROS). Here a microfabricated ROS modulation device that relies on controlled faradaic reactions is presented. A concentric pixel arrangement of a peroxide-evolving cathode surrounded by an anode ring which decomposes the peroxide, resulting in localized peroxide delivery is reported. The conducting polymer (poly(3,4-ethylenedioxythiophene) (PEDOT), is exploited as the cathode. PEDOT selectively catalyzes the oxygen reduction reaction resulting in the production of hydrogen peroxide (H2O2). Using electrochemical and optical assays, combined with modeling, the performance of the devices is benchmarked. The concentric pixels generate tunable gradients of peroxide and oxygen concentrations. The faradaic devices are prototyped by modulating human H2O2-sensitive Kv7.2/7.3 (M-type) channels expressed in a single-cell model (Xenopus laevis oocytes). The Kv7 ion channel family is responsible for regulating neuronal excitability in the heart, brain, and smooth muscles, making it an ideal platform for faradaic ROS stimulation. The results demonstrate the potential of PEDOT to act as an H2O2 delivery system, paving the way to ROS-based organic bioelectronics.

    Fulltekst (pdf)
    fulltext
  • 35. Bestill onlineKjøp publikasjonen >>
    Abedini, Fereshteh
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    2D and 3D Halftoning for Appearance Reproduction2023Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The appearance of an object is determined by its chromatic and geometric qualities in its surrounding environment using four optical parameters: color, gloss, translucency, and surface texture. Reconstructing the appearance of objects is of great importance in many applications, including creative industries, packaging, fine-art reproduction, medical simulation, and prosthesis-making. Printers are reproduction devices capable of replicating objects’ appearance in 2D and 3D forms. With the introduction of new printing technologies, new inks and materials, and demands for innovative applications, creating accurate reproduction of the desired visual appearance has become challenging. Thus, the appearance reproduction workflow requires improvements and adaptations. 

    Accurate color reproduction is a critical quality measure in reproducing the desired appearance in any printing process. However, printers are devices with a limited number of inks that can either print a dot or leave it blank at a specific position on a substrate; hence, to reproduce different colors, optimal placement of the available inks is needed. Halftoning is a technique that deals with this challenge by generating a spatial distribution of the available inks that creates an illusion of the target color when viewed from a sufficiently large distance. Halftoning is a fundamental part of the color reproduction task in any full-color printing pipeline, and it is an effective technique to increase the potential of printing realistic and complex appearances. Although halftoning has been used in 2D printing for many decades, it still requires improvements in reproducing fine details and structures of images. Moreover, the emergence of new technologies in 3D printing introduces a higher degree of freedom and more parameters to the field of appearance reproduction. Therefore, there is a critical need for extensive studies to revisit existing halftoning algorithms and develop novel approaches to produce high quality prints that match the target appearance faithfully. This thesis aims at developing halftoning algorithms to improve appearance reproduction in 2D and 3D printing. 

    Contributions of this thesis in the 2D domain is a dynamic sharpness-enhancing halftoning approach, which adaptively varies the local sharpness of the halftone image based on different textures in the original image for realistic appearance printing. The results show improvements in halftone quality in terms of sharpness, preserving structural similarity, and decreasing color reproduction error. The main contribution of this thesis in 3D printing is extending a high quality 2D halftoning algorithm to the 3D domain. The proposed method is then integrated with a multi-layer printing approach, where ink is deposited at variable depths to improve the reproduction of tones and fine details. Results demonstrate that the proposed method accurately reproduces tones and details of the target appearance. Another contribution of this thesis is studying the effect of halftoning on the perceived appearance of 3D printed surfaces. According to the results, changing the dot placement based on the elevation variation of the underlying geometry can potentially control the perception of the 3D printed appearance. It implies that the choice of halftone may prove helpful in eliminating unwanted artifacts, enhancing the object’s geometric features, and producing a more accurate 3D appearance. The proposed methods in this thesis have been evaluated using different printing techniques.    

    Delarbeid
    1. 3D Halftoning based on Iterative Method Controlling Dot Placement
    Åpne denne publikasjonen i ny fane eller vindu >>3D Halftoning based on Iterative Method Controlling Dot Placement
    2020 (engelsk)Konferansepaper, Oral presentation with published abstract (Fagfellevurdert)
    Abstract [en]

    Realistic appearance reproduction is of great importance in 3D printing’s applications. Halftoning as a necessary process in printing has a great impact on creating visually pleasant appearance. In this article, we study the aspects of adapting and applying Iterative Method Controlling Dot Placement (IMCDP) to halftone three-dimensional surfaces. Our main goal is to extend the 2D algorithm to a 3D halftoning approach with minor modifications. The results show high-quality reproduction for all gray tones. The 3D halftoning algorithm is not only free of undesirable artifacts, it also produces fully symmetric and wellformed halftone structures even in highlight and shadow regions.

    Emneord
    3D printing, 3D halftoning, Surface reproduction
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-171744 (URN)10.2352/ISSN.2169-4451.2020.36.69 (DOI)
    Konferanse
    Printing for Fabrication, Online 2020, October 19-21
    Tilgjengelig fra: 2020-12-01 Laget: 2020-12-01 Sist oppdatert: 2023-09-26bibliografisk kontrollert
    2. 3D Surface Structures and 3D Halftoning
    Åpne denne publikasjonen i ny fane eller vindu >>3D Surface Structures and 3D Halftoning
    2020 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    As 3D printing is becoming increasingly popular, the demand for high quality surface reproduction is also increasing. Like in 2D printing, halftoning plays an important role in the quality of the surface reproduction. Developing advanced 3D halftoning methods for 3D printing and adapting them to the structure of the surface is therefore essential for improving surface reproduction quality. In this paper, an extension of an iterative 2D halftoning method to 3D is used to apply different halftone structures on 3D surfaces. The results show that using different halftones based on the 3D geometrical structure of the surface and/or the viewing angle in combination with the structure of the texture being mapped on the surface can potentially improve the quality of the appearance of 3D surfaces.

    sted, utgiver, år, opplag, sider
    The Society for Imaging Science and Technology, 2020
    Emneord
    3D halftoning, Hybrid halftoning, 3D surface structures
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-170797 (URN)10.2352/ISSN.2169-4451.2020.36.75 (DOI)
    Konferanse
    Printing for Fabrication 2020
    Tilgjengelig fra: 2020-10-22 Laget: 2020-10-22 Sist oppdatert: 2024-01-02bibliografisk kontrollert
    3. The Effect of Halftoning on the Appearance of 3D Printed Surfaces
    Åpne denne publikasjonen i ny fane eller vindu >>The Effect of Halftoning on the Appearance of 3D Printed Surfaces
    2021 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Managing the final appearance of 3D surfaces is an interesting and essential topic in 3D printing applications. Knowledge about the parameters which influence the 3D surface reproduction quality enables engineers to achieve the final appearance as accurately as designed. Many studies have been conducted to explore numerous parameters that affect the quality of 3D surface reproduction. This work contributes to verifying the role of halftoning in increasing the 3D surface visual quality and the control over the surface appearance of a 3D printed object. The results show that applying different halftones according to the geometrical characteristics of the 3D surface could emphasize or diminish the perceived 3D geometrical structures of a shape. The experimental results are in line with the simulated outputs reported in previous work. Our findings might introduce a new approach towards having more control over 3D appearance reproduction without changing the material or printer settings.

    Emneord
    3D printing, Halftoning, Surface appearance
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-180696 (URN)
    Konferanse
    47th Annual Conference of Iarigai
    Tilgjengelig fra: 2021-10-29 Laget: 2021-10-29 Sist oppdatert: 2023-09-26bibliografisk kontrollert
    4. Structure-Aware Halftoning Using the Iterative Method Controlling the Dot Placement
    Åpne denne publikasjonen i ny fane eller vindu >>Structure-Aware Halftoning Using the Iterative Method Controlling the Dot Placement
    2021 (engelsk)Inngår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 65, nr 6Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Many image reproduction devices, such as printers, are limited to only a few numbers of printing inks. Halftoning, which is the process to convert a continuous-tone image into a binary one, is, therefore, an essential part of printing. An iterative halftoning method, called Iterative Halftoning Method Controlling the Dot Placement (IMCDP), which has already been studied by research scholars, generally results in halftones of good quality. In this paper, we propose a structure-based alternative to this algorithm that improves the halftone image quality in terms of sharpness, structural similarity, and tone preservation. By employing appropriate symmetrical and non-symmetrical Gaussian filters inside the proposed halftoning method, it is possible to adaptively change the degree of sharpening in different parts of the continuous-tone image. This is done by identifying a dominant line in the neighborhood of each pixel in the original image, utilizing the Hough Transform, and aligning the dots along the dominant line. The objective and subjective quality assessments verify that the proposed structure-based method not only results in sharper halftones, giving more three-dimensional impression, but also improves the structural similarity and tone preservation. The adaptive nature of the proposed halftoning method makes it an appropriate algorithm to be further developed to a 3D halftoning method, which could be adapted to different parts of a 3D object by exploiting both the structure of the images being mapped and the 3D geometrical structure of the underlying printed surface.

    sted, utgiver, år, opplag, sider
    I S & T-SOC IMAGING SCIENCE TECHNOLOGY, 2021
    Emneord
    Halftoning, Structure-Aware Halftoning, Hough Transform, Image Quality Evaluation
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-181613 (URN)10.2352/j.imagingsci.technol.2021.65.6.060404 (DOI)000734009600011 ()
    Merknad

    Funding: ApPEARS (Appearance Printing European Advanced Research School); European Unions Horizon 2020 programme under the Marie Skodowska-Curie [814158]

    Tilgjengelig fra: 2021-12-04 Laget: 2021-12-04 Sist oppdatert: 2023-09-26bibliografisk kontrollert
    5. Structure-Aware Color Halftoning with Adaptive Sharpness Control
    Åpne denne publikasjonen i ny fane eller vindu >>Structure-Aware Color Halftoning with Adaptive Sharpness Control
    2022 (engelsk)Inngår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 66, nr 6, artikkel-id 060404Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Structure-aware halftoning algorithms aim at improving their non-structure-aware version by preserving high-frequency details, structures, and tones and by employing additional information from the input image content. The recently proposed achromatic structure-aware Iterative Method Controlling the Dot Placement (IMCDP) halftoning algorithm uses the angle of the dominant line in each pixels neighborhood as supplementary information to align halftone structures with the dominant orientation in each region and results in sharper halftones, gives a more three-dimensional impression, and improves the structural similarity and tone preservation. However, this method is developed only for monochrome halftoning, the degree of sharpness enhancement is constant for the entire image, and the algorithm is prohibitively expensive for large images. In this paper, we present a faster and more flexible approach for representing the image structure using a Gabor-based orientation extraction technique which improves the computational performance of the structure-aware IMCDP by an order of magnitude while improving the visual qualities. In addition, we extended the method to color halftoning and studied the impact of orientation information in different color channels on improving sharpness enhancement, preserving structural similarity, and decreasing color reproduction error. Furthermore, we propose a dynamic sharpness enhancement approach, which adaptively varies the local sharpness of the halftone image based on different textures across the image. Our contributions in the present work enable the algorithm to adaptively work on large images with multiple regions and different textures. (C) 2022 Society for Imaging Science and Technology.

    sted, utgiver, år, opplag, sider
    I S & T-SOC IMAGING SCIENCE TECHNOLOGY, 2022
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-192705 (URN)10.2352/J.ImagingSci.Technol.2022.66.6.060404 (DOI)000939908300011 ()
    Merknad

    Funding Agencies|ApPEARS (Appearance Printing European Advanced Research School); European Unions Horizon 2020 programme under the Marie Sklodowska-Curie grant [814158]

    Tilgjengelig fra: 2023-03-31 Laget: 2023-03-31 Sist oppdatert: 2023-09-26
    6. Effect of halftones on printing iridescent colors
    Åpne denne publikasjonen i ny fane eller vindu >>Effect of halftones on printing iridescent colors
    2023 (engelsk)Inngår i: IS&T Electronic Imaging: Color Imaging XXVIII: Displaying, Processng, Hardcopy, and Applications, The Society for Imaging Science and Technology, 2023, Vol. 35, s. 1-6Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    The iridescent effect produced by structural color is difficult (if not impossible) to capture and print using traditional CMYK pigments. The so called RGB reflective pigments, nonetheless, generate angle-dependent colors by light interference. A layered surface structure generated by the pigments’ particles on a substrate reflects light waves of different wavelengths at different viewing angles according to the optical principle known as the Bragg Law. In this work, we have studied the influence of different halftone structures on printed images, produced with RGB reflective inks via screen printing. The main goal was to enhance the iridescence of a printed reproduction by studying the performance of different halftone algorithms on a screen printing process. We investigated the influence of different halftone structures in creating different spatial combinations of inks on a print to reproduce the image of an iridescent feathered headdress. We applied first-order, second-order, and structure-aware FM halftones to compare how they influence the reproduction of the material appearance of the object represented in the original image. The results show that the structure-ware halftones improve the representation of the image structures and details. Therefore, it could better convey the 3D surface features that produce iridescence in real feathers.

    sted, utgiver, år, opplag, sider
    The Society for Imaging Science and Technology, 2023
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-197992 (URN)
    Konferanse
    IS&T Electronic Imaging
    Tilgjengelig fra: 2023-09-20 Laget: 2023-09-20 Sist oppdatert: 2023-09-26
    Fulltekst (pdf)
    fulltext
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    presentationsbild
  • 36.
    Abedini, Fereshteh
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Effect of halftones on printing iridescent colors2023Inngår i: IS&T Electronic Imaging: Color Imaging XXVIII: Displaying, Processng, Hardcopy, and Applications, The Society for Imaging Science and Technology, 2023, Vol. 35, s. 1-6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The iridescent effect produced by structural color is difficult (if not impossible) to capture and print using traditional CMYK pigments. The so called RGB reflective pigments, nonetheless, generate angle-dependent colors by light interference. A layered surface structure generated by the pigments’ particles on a substrate reflects light waves of different wavelengths at different viewing angles according to the optical principle known as the Bragg Law. In this work, we have studied the influence of different halftone structures on printed images, produced with RGB reflective inks via screen printing. The main goal was to enhance the iridescence of a printed reproduction by studying the performance of different halftone algorithms on a screen printing process. We investigated the influence of different halftone structures in creating different spatial combinations of inks on a print to reproduce the image of an iridescent feathered headdress. We applied first-order, second-order, and structure-aware FM halftones to compare how they influence the reproduction of the material appearance of the object represented in the original image. The results show that the structure-ware halftones improve the representation of the image structures and details. Therefore, it could better convey the 3D surface features that produce iridescence in real feathers.

  • 37.
    Abedini, Fereshteh
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Structure-Aware Color Halftoning with Adaptive Sharpness Control2022Inngår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 66, nr 6, artikkel-id 060404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Structure-aware halftoning algorithms aim at improving their non-structure-aware version by preserving high-frequency details, structures, and tones and by employing additional information from the input image content. The recently proposed achromatic structure-aware Iterative Method Controlling the Dot Placement (IMCDP) halftoning algorithm uses the angle of the dominant line in each pixels neighborhood as supplementary information to align halftone structures with the dominant orientation in each region and results in sharper halftones, gives a more three-dimensional impression, and improves the structural similarity and tone preservation. However, this method is developed only for monochrome halftoning, the degree of sharpness enhancement is constant for the entire image, and the algorithm is prohibitively expensive for large images. In this paper, we present a faster and more flexible approach for representing the image structure using a Gabor-based orientation extraction technique which improves the computational performance of the structure-aware IMCDP by an order of magnitude while improving the visual qualities. In addition, we extended the method to color halftoning and studied the impact of orientation information in different color channels on improving sharpness enhancement, preserving structural similarity, and decreasing color reproduction error. Furthermore, we propose a dynamic sharpness enhancement approach, which adaptively varies the local sharpness of the halftone image based on different textures across the image. Our contributions in the present work enable the algorithm to adaptively work on large images with multiple regions and different textures. (C) 2022 Society for Imaging Science and Technology.

  • 38.
    Abedini, Fereshteh
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Kitanovski, Vlado
    Norwegian University of Science and Technology, Faculty of Information Technology and Electrical Engineering, Department of Computer Science, Gjøvik, Norway.
    Nyström, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Structure-Aware Halftoning Using the Iterative Method Controlling the Dot Placement2021Inngår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 65, nr 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many image reproduction devices, such as printers, are limited to only a few numbers of printing inks. Halftoning, which is the process to convert a continuous-tone image into a binary one, is, therefore, an essential part of printing. An iterative halftoning method, called Iterative Halftoning Method Controlling the Dot Placement (IMCDP), which has already been studied by research scholars, generally results in halftones of good quality. In this paper, we propose a structure-based alternative to this algorithm that improves the halftone image quality in terms of sharpness, structural similarity, and tone preservation. By employing appropriate symmetrical and non-symmetrical Gaussian filters inside the proposed halftoning method, it is possible to adaptively change the degree of sharpening in different parts of the continuous-tone image. This is done by identifying a dominant line in the neighborhood of each pixel in the original image, utilizing the Hough Transform, and aligning the dots along the dominant line. The objective and subjective quality assessments verify that the proposed structure-based method not only results in sharper halftones, giving more three-dimensional impression, but also improves the structural similarity and tone preservation. The adaptive nature of the proposed halftoning method makes it an appropriate algorithm to be further developed to a 3D halftoning method, which could be adapted to different parts of a 3D object by exploiting both the structure of the images being mapped and the 3D geometrical structure of the underlying printed surface.

    Download (png)
    preview image
  • 39.
    Abedini, Fereshteh
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Nyström, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    3D Halftoning based on Iterative Method Controlling Dot Placement2020Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Realistic appearance reproduction is of great importance in 3D printing’s applications. Halftoning as a necessary process in printing has a great impact on creating visually pleasant appearance. In this article, we study the aspects of adapting and applying Iterative Method Controlling Dot Placement (IMCDP) to halftone three-dimensional surfaces. Our main goal is to extend the 2D algorithm to a 3D halftoning approach with minor modifications. The results show high-quality reproduction for all gray tones. The 3D halftoning algorithm is not only free of undesirable artifacts, it also produces fully symmetric and wellformed halftone structures even in highlight and shadow regions.

    Download (png)
    preview image
  • 40.
    Abedini, Fereshteh
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Nyström, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    The Effect of Halftoning on the Appearance of 3D Printed Surfaces2021Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Managing the final appearance of 3D surfaces is an interesting and essential topic in 3D printing applications. Knowledge about the parameters which influence the 3D surface reproduction quality enables engineers to achieve the final appearance as accurately as designed. Many studies have been conducted to explore numerous parameters that affect the quality of 3D surface reproduction. This work contributes to verifying the role of halftoning in increasing the 3D surface visual quality and the control over the surface appearance of a 3D printed object. The results show that applying different halftones according to the geometrical characteristics of the 3D surface could emphasize or diminish the perceived 3D geometrical structures of a shape. The experimental results are in line with the simulated outputs reported in previous work. Our findings might introduce a new approach towards having more control over 3D appearance reproduction without changing the material or printer settings.

    Download (png)
    preview image
  • 41.
    Abelow, Alexis
    et al.
    University of Utah, Salt Lake City, USA.
    Persson, Kristin
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Jager, Edwin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Zharov, Ilya
    University of Utah, Salt Lake City, USA.
    Electroresponsive Nanoporous Membranes by Coating Anodized Alumina with Poly(3,4-ethylenedioxythiophone) and Polypyrrole2014Inngår i: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054, Vol. 299, nr 2, s. 190-197Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrically-active nanoporous membranes are prepared by coating the surface of anodized alumina with electroactive polymers using vapor phase polymerization with four combinations of conjugated polymers and doping ions: poly(3,4-ethylenedioxythiophone) and polypyrrole, FeCl3 and FeTs3. The permeability of the polymer-coated membranes is measured as a function of the applied electric potential. A reversible three-fold increase is found in molecular flux of a neutral dye for membranes in oxidized state compared to that in the reduced state. After analyzing various factors that may affect the molecular transport through these membranes, it is concluded that the observed behavior results mostly from swelling/deswelling of the polymers and from the confinement of the polymers inside the nanopores.

  • 42.
    Abo Al Ahad, George
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Nationalekonomi. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik.
    Gerzic, Denis
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Nationalekonomi. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik.
    A Study on the Low Volatility Anomaly in the Swedish Stock Exchange Market: Modern Portfolio Theory2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study investigates, with a critical approach, if portfolios consisting of high beta stocks yields more than portfolios consisting of low beta stocks in the Swedish stock exchange market. The chosen period is 1999-2016, covering both the DotCom Bubble and the financial crisis of 2008. We also investigate if the Capital Asset Pricing Model is valid by doing a test similar to Fama and Macbeth’s of 1973.

    Based on earlier studies in the field and our own study we come to the conclusion that high beta stocks does not outperform low beta stocks in the Swedish stock market 1999-2016. We believe that this relationship arises from inefficiencies in the market and irrational investing. By doing this study we observe that, the use of beta as the only risk factor for explaining expected returns on stocks or portfolios is not correct.

    Fulltekst (pdf)
    fulltext
  • 43.
    Abrahamsson, Jesper
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ett försprång till skapande - en undersökning om förutsättningarna för Musikproduktion på Kulturskolan2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med rapporten är att undersöka förutsättningarna för en introduktionskurs i musikproduktion på Kulturskolan i Karlskrona, samt att utforma en övergripande plan för undervisningen. Arbetet omfattar även en mindre undersökning av eventuella liknande kurser på kulturskolor i tolv större svenska städer. För att besvara frågeställningarna har intervjuer genomförts med lärare och ledning på Kulturskolan i Karlskrona, anställda på kulturskolor på andra orter, musikgymnasium i Karlskrona samt på kommunens kulturförvaltning. Undersökningen visade att endast två av tolv städer har motsvarande eller liknande kurser på sina kulturskolor. De materiella förutsättningarna för en musikproduktionskurs på Kulturskolan i Karlskrona är goda, i form av lokaler med befintlig ljudutrustning och programvara. När det gäller ekonomiska förutsättningar kommer Kulturskolans intäkter från elevavgifter och kommunala medel. Kursen skulle innebära en utgift för lärarlön, men i övrigt går den att starta utan ytterligare kostnader. På kommunens kulturförvaltning menar man att det är viktigt med bredd i Kulturskolans kursutbud och att en musikproduktionskurs kan berika det lokala kulturlivet. Kursen är tänkt att fokusera på musik med datorn. Momenten bör kretsa kring inspelningsprogram, mjukvaruinstrument, plugin-program, med inslag av arrangering och mixning. Kursens målsättningar ligger i linje med Kulturskolans policydokument och är inspirerade av liknande kurser på andra kulturskolor.

    Fulltekst (pdf)
    fulltext
  • 44.
    Abrahamsson, Johan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Loop impedance measurement tool2020Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master´s thesis presents a prototype of a hand-held measurement tool used to measure the loop impedance of ground loops using two current probes. This tool allows the user to find bad shield connections in a system without disconnecting the shielded cables. The thesis explains the theory behind the measurement method, hardware requirements and design, how the software works and a demonstration of the implemented graphical user interface. The tool is powered by a two-cell lithium-ion battery and has an integrated battery charger with cell balancing.

    Fulltekst (pdf)
    fulltext
  • 45.
    Abrahamsson, Kalle
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Åtgärd för ökad trafiksäkerhet - Undersökning om behovet av nya säkra övergångar vid Riksväg 51 i Finspång2020Independent thesis Basic level (university diploma), 10,5 poäng / 16 hpOppgave
    Abstract [sv]

    Fordonstrafiken ökar allt mer i Sverige, antalet lastbilstransporter likaså riksväg 51 står inför nybyggnation som ska öka framkomligheten för fordon genom Finspång, men vem tänker på gång och cykeltrafikanterna? Denna rapport undersöker framkomligheten för en problematisk sträcka av Riksväg 51 genom Finspång, där hastighetsbegränsningen är hög och bristen på säkra övergångar är stor. Passageräkning kommer utföras vid två områden för att få svar på hur stort problemet är för Finspångs invånare. Rapporten resulterar i förslag till två nya säkra övergångar, en gångbro vid Postnords kontor i Finspång och en tunnel intill en cirkulationsplats i anslutning till Willys i Finspång. Om kommunen anser att dessa förslag är något att arbeta vidare med är helt upp till dem.

    Fulltekst (pdf)
    fulltext
  • 46. Bestill onlineKjøp publikasjonen >>
    Abrahamsson, Tobias
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Synthetic Functionalities for Ion and Electron Conductive Polymers: Applications in Organic Electronics and Biological Interfaces2021Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In the search for understanding and communicating with all biological systems, in humans, animals, plants, and even microorganisms, we find a common language of all communicating via electrons, ions and molecules. Since the discovery of organic electronics, the ability to bridge the gap and communicate be-tween modern technology and biology has emerged. Organic chemistry pro-vides us with tools for understanding and a material platform of polymer electronics for communication. Such insights give us not only the ability to observe fundamental phenomenon but to actively design and construct materials with chemical functionalities towards better interfaces and applications. Organic electronic materials and devices have found their way to be implemented in the field of medicine for diagnostic and therapeutic purposes, but also in water purification and to help tackle the monumental task in creating the next generation of sustainable energy production and storage. Ultimately it’s safe to say that organic electronics are not going to replace our traditional technology based on inorganic materials but rather the two fields can find a way to complement each other for various purposes and applications. Compared to conventional silicon based technology, production of carbon-based organic electronic polymer materials are extremely cheap and devices can even be made flexible and soft with great compatibility towards biology.  

    The main focus of this thesis has been developing and synthesizing new types of organic electronic and ionic conductive polymeric materials. Rational chemical design and modifications of the materials have been utilized to introduce specific functionalities to the materials. The functionalities serving the purpose to facilitate ion and electron conductive charge transport for organic electronics and with biological interface implementation of the polymer materials. 

    Multi-functional ionic conductive hyperbranched polyglycerol polyelectrolytes (dendrolytes) were developed comprising both ionically charged groups and cross-linkable groups. The hyperbranched polyglycerol core structure of the material possesses a hydrophilic solvating platform for both ions and maintenance of solvent molecules, while being a biocompatible structure. Coupled with the peripheral charged ionic functionalities of the polymer, the dendrolyte materials are highly ionic conductive and selective towards cationic and anionic charged atoms and large molecules when implemented as ion-exchange membranes. Homogenous ion-exchange membrane casting has been achieved by the implementation of cross-linkable functionalities in the dendrolytes, utilizing robust click-chemistry for efficient micro and macro fabrication processing of the ion-ex-change membranes for organic electronic devices. The ion-exchange membrane material was implemented in electrophoretic drug delivery devices (organic electronic ion pumps), which are used for delivery of ions and neurotransmitters with spatiotemporal resolution and are able to communicate and be used for therapeutic drug delivery purposes in biological interfaces. The dendrolyte materials were also able to form free-standing membranes, making it possible for implementation in fuel cell and desalination purposes. 

    Trimeric conjugated thiophene pre-polymer structures were also developed in the thesis and synthesized for the purpose of implementation of the material in vivo to form electrically conductive polymer structures, and in such manner to be able to create electrodes and ultimately to connect with the central nervous system. The conjugated pre-polymers being both water soluble and enzymatically polymerizable serve as a platform to realize such a concept. Also, modifying the trimeric structure with cross-linkable functionality created the capability to form better interfaces and stability towards biological environments.   

    Delarbeid
    1. Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol
    Åpne denne publikasjonen i ny fane eller vindu >>Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol
    Vise andre…
    2019 (engelsk)Inngår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, artikkel-id 484Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

    sted, utgiver, år, opplag, sider
    FRONTIERS MEDIA SA, 2019
    Emneord
    hyperbranched polyglycerol; polyelectrolyte; multi-functionalization; thiol-ene; cross-linking; ion-selective; electrophoretic transport
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-159146 (URN)10.3389/fchem.2019.00484 (DOI)000474717900001 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University; Onnesjo Foundation; Knut and AliceWallenberg Foundation

    Tilgjengelig fra: 2019-07-30 Laget: 2019-07-30 Sist oppdatert: 2024-01-10
    2. Capillary-Fiber Based Electrophoretic Delivery Device
    Åpne denne publikasjonen i ny fane eller vindu >>Capillary-Fiber Based Electrophoretic Delivery Device
    Vise andre…
    2019 (engelsk)Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 15, s. 14200-14207Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Organic electronic ion pumps (OEIPs) are versatile tools for electrophoretic delivery of substances with high spatiotemporal resolution. To date, OEIPs and similar iontronic components have been fabricated using thin-film techniques and often rely on laborious, multistep photolithographic processes. OEIPs have been demonstrated in a variety of in vitro and in vivo settings for controlling biological systems, but the thin-film form factor and limited repertoire of polyelectrolyte materials and device fabrication techniques unnecessarily constrain the possibilities for miniaturization and extremely localized substance delivery, e.g., the greater range of pharmaceutical compounds, on the scale of a single cell. Here, we demonstrate an entirely new OEIP form factor based on capillary fibers that include hyperbranched polyglycerols (dPGs) as the selective electrophoretic membrane. The dPGs enable electrophoretic channels with a high concentration of fixed charges and well-controlled cross-linking and can be realized using a simple one-pot fluidic manufacturing protocol. Selective electrophoretic transport of cations and anions of various sizes is demonstrated, including large substances that are difficult to transport with other OEIP technologies. We present a method for tailoring and characterizing the electrophoretic channels fixed charge concentration in the operational state. Subsequently, we compare the experimental performance of these capillary OEIPs to a computational model and explain unexpected features in the ionic current for the transport and delivery of larger, lower-mobility ionic compounds. From this model, we are able to elucidate several operational and design principles relevant to miniaturized electrophoretic drug delivery technologies in general. Overall, the compactness of the capillary OEIP enables electrophoretic delivery devices with probelike geometries, suitable for a variety of ionic compounds, paving the way for less-invasive implantation into biological systems and for healthcare applications.

    sted, utgiver, år, opplag, sider
    AMER CHEMICAL SOC, 2019
    Emneord
    electrophoresis; polyelectrolyte; iontronics; hyperbranched polymer; bioelectronics; substance delivery
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-157207 (URN)10.1021/acsami.8b022680 (DOI)000465189000042 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Onnesjo Foundation; Knut and Alice Wallenberg Foundation

    Tilgjengelig fra: 2019-06-14 Laget: 2019-06-14 Sist oppdatert: 2024-01-10
    3. Investigating the role of polymer size on ionic conductivity in free-standing hyperbranched polyelectrolyte membranes
    Åpne denne publikasjonen i ny fane eller vindu >>Investigating the role of polymer size on ionic conductivity in free-standing hyperbranched polyelectrolyte membranes
    Vise andre…
    2021 (engelsk)Inngår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 223, artikkel-id 123664Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Polymer-based ion exchange membranes (IEMs) are utilized for many applications such as in water desalination, energy storage, fuel cells and in electrophoretic drug delivery devices, exemplified by the organic electronic ion pump (OEIP). The bulk of current research is primarily focused on finding highly conductive and stable IEM materials. Even though great progress has been made, a lack of fundamental understanding of how specific polymer properties affect ionic transport capabilities still remains. This leads to uncertainty in how to proceed with synthetic approaches for designing better IEM materials. In this study, an investigation of the structure-property relationship between polymer size and ionic conductivity was performed by comparing a series of membranes, based on ionically charged hyperbranched polyglycerol of different polymer sizes. Observing an increase in ionic conductivity associated with increasing polymer size and greater electrolyte exclusion, indi-cating an ionic transportation phenomenon not exclusively based on membrane electrolyte uptake. These findings further our understanding of ion transport phenomena in semi-permeable membranes and indicate a strong starting point for future design and synthesis of IEM polymers to achieve broader capabilities for a variety of ion transport-based applications.

    sted, utgiver, år, opplag, sider
    Elsevier, 2021
    Emneord
    Ion-exchange membrane; Polymer size dependant ionic conductivity; Hyperbranched polyelectrolyte; Multi-functionalization; Click cross-linking
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-175830 (URN)10.1016/j.polymer.2021.123664 (DOI)000643930300006 ()
    Merknad

    Funding Agencies|Swiss Society for Biomaterials and Regenerative Medicine, SSB + RM; Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research; Swedish Research CouncilSwedish Research CouncilEuropean Commission; European UnionEuropean Commission [834677]

    Tilgjengelig fra: 2021-05-26 Laget: 2021-05-26 Sist oppdatert: 2023-12-28
    4. Seamless integration of bioelectronic interface in an animal model via in vivo polymerization of conjugated oligomers
    Åpne denne publikasjonen i ny fane eller vindu >>Seamless integration of bioelectronic interface in an animal model via in vivo polymerization of conjugated oligomers
    Vise andre…
    2022 (engelsk)Inngår i: Bioactive Materials, ISSN 2452-199X, Vol. 10, s. 107-116Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Leveraging the biocatalytic machinery of living organisms for fabricating functional bioelectronic interfaces, in vivo, defines a new class of micro-biohybrids enabling the seamless integration of technology with living biological systems. Previously, we have demonstrated the in vivo polymerization of conjugated oligomers forming conductors within the structures of plants. Here, we expand this concept by reporting that Hydra, an invertebrate animal, polymerizes the conjugated oligomer ETE-S both within cells that expresses peroxidase activity and within the adhesive material that is secreted to promote underwater surface adhesion. The resulting conjugated polymer forms electronically conducting and electrochemically active μm-sized domains, which are inter-connected resulting in percolative conduction pathways extending beyond 100 μm, that are fully integrated within the Hydra tissue and the secreted mucus. Furthermore, the introduction and in vivo polymerization of ETE-S can be used as a biochemical marker to follow the dynamics of Hydra budding (reproduction) and regeneration. This work paves the way for well-defined self-organized electronics in animal tissue to modulate biological functions and in vivo biofabrication of hybrid functional materials and devices.

    sted, utgiver, år, opplag, sider
    Elsevier, 2022
    Emneord
    polymerization, Bioelectronics interfaces, Conjugated oligomers, Model organism
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-181716 (URN)10.1016/j.bioactmat.2021.08.025 (DOI)000743377900002 ()34901533 (PubMedID)
    Merknad

    Funding agencies: European Unions Horizon 2020 research and innovation programme [800926]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR-2017-04910]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research; European Research Council (ERC)European Research Council (ERC)European Commission [834677]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; MultiPark - A Strategic Research Area at Lund University; MIURMinistry of Education, Universities and Research (MIUR) [SHARID - ARS01-01270]

    Tilgjengelig fra: 2021-12-07 Laget: 2021-12-07 Sist oppdatert: 2022-10-12bibliografisk kontrollert
    Fulltekst (pdf)
    fulltext
    Download (png)
    presentationsbild
  • 47.
    Abrahamsson, Tobias
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Poxson, David
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Gabrielsson, Erik
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Sandberg, Mats
    RISE Acreo AB, Sweden.
    Simon, Daniel T
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol2019Inngår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, artikkel-id 484Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

    Fulltekst (pdf)
    fulltext
  • 48.
    Abrahamsson, Tobias
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Seitanidou, Maria S
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Roy, Arghyamalya
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Phopase, Jaywant
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Petsagkourakis, Ioannis
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Moro, Nathalie
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. Empa, Switzerland.
    Tybrandt, Klas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Simon, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Investigating the role of polymer size on ionic conductivity in free-standing hyperbranched polyelectrolyte membranes2021Inngår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 223, artikkel-id 123664Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polymer-based ion exchange membranes (IEMs) are utilized for many applications such as in water desalination, energy storage, fuel cells and in electrophoretic drug delivery devices, exemplified by the organic electronic ion pump (OEIP). The bulk of current research is primarily focused on finding highly conductive and stable IEM materials. Even though great progress has been made, a lack of fundamental understanding of how specific polymer properties affect ionic transport capabilities still remains. This leads to uncertainty in how to proceed with synthetic approaches for designing better IEM materials. In this study, an investigation of the structure-property relationship between polymer size and ionic conductivity was performed by comparing a series of membranes, based on ionically charged hyperbranched polyglycerol of different polymer sizes. Observing an increase in ionic conductivity associated with increasing polymer size and greater electrolyte exclusion, indi-cating an ionic transportation phenomenon not exclusively based on membrane electrolyte uptake. These findings further our understanding of ion transport phenomena in semi-permeable membranes and indicate a strong starting point for future design and synthesis of IEM polymers to achieve broader capabilities for a variety of ion transport-based applications.

    Fulltekst (pdf)
    fulltext
  • 49.
    Abrikosov, Alexei I.
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Masood, Talha Bin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Falk, Martin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Topological analysis of density fields: An evaluation of segmentation methods2021Inngår i: Computers & graphics, ISSN 0097-8493, E-ISSN 1873-7684, Vol. 98, s. 231-241Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Topological and geometric segmentation methods provide powerful concepts for detailed field analysis and visualization. However, when it comes to a quantitative analysis that requires highly accurate geometric segmentation, there is a large discrepancy between the promising theory and the available computational approaches. In this paper, we compare and evaluate various segmentation methods with the aim to identify and quantify the extent of these discrepancies. Thereby, we focus on an application from quantum chemistry: the analysis of electron density fields. It is a scalar quantity that can be experimentally measured or theoretically computed. In the evaluation we consider methods originating from the domain of quantum chemistry and computational topology. We apply the methods to the charge density of a set of crystals and molecules. Therefore, we segment the volumes into atomic regions and derive and compare quantitative measures such as total charge and dipole moments from these regions. As a result, we conclude that an accurate geometry determination can be crucial for correctly segmenting and analyzing a scalar field, here demonstrated on the electron density field.

    Fulltekst (pdf)
    fulltext
  • 50.
    Abrikosov, Alexei I.
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Veryazov, Valera
    Theoretical Chemistry, Lund University, Lund, Sweden.
    Multiscale Modelling of Atomistic Structure of Calcium Silicate Hydrate2022Inngår i: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Solid State Phenomena, Vol. 338, s. 123-128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The atomistic structure of calcium-silicate-hydrate (C-S-H) has been studied by applying force field simulations and quantum mechanical methods. Large number of crystallographically equivalent structures were used to account for the disordered nature of C-S-H. An extensive set of periodic structures of C-S-H (with a variation of chemical composition) has been generated and optimised. Special attention has been paid to two crystallographic models for tobermorite, which are used for the construction of C-S-H models. Re-optimisation of atomic structures, initially optimised with ReaxFF force field, by quantum chemical methods (semiempirical and Density functional theory) have been performed. Although the main structural characteristics of C-S-H remain the same in all calculations, the balance between the amount of OH groups and water in the structure is different. The obtained structures (optimised with a different level of theory) are combined into an on-line database and can be used for a future simulation of C-S-H materials.

1234567 1 - 50 of 7198
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