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  • 1. Beställ onlineKöp publikationen >>
    Ahlbeck, Lars
    Linköpings universitet, Institutionen för biomedicinska och kliniska vetenskaper, Avdelningen för inflammation och infektion. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Medicincentrum, Allergicentrum US.
    Intralymphatic Immunotherapy: A Novel Route to Ameliorate Allergic Rhinitis Due to Pollen2024Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Allergy to pollen and animal dander is a major public health problem. Close to 30% of the population have symptoms from the upper and/or lower respiratory tract when they meet fur animals or pollen. Whereas symptom-relieving medications have a good to sufficient effect on about 80% of those affected, a large group of 10–20% have severe symptoms, despite medication, with an impact on well-being and ability to work. In Sweden, the annual cost of allergy was calculated at €1.3 billion in 2014.

    Immunotherapy is effective in treating and preventing pollen allergy and allergic asthma, but is expensive, complicated, requiring 40 injections, and takes more than three years to complete if subcutaneous injections are used. Tablets placed under the tongue are another method, with one tablet taken every day for three years. Only 1.5‰ receive such treatment, yet just over 3% would need it.

    With intralymphatic immunotherapy, a small dose of allergen is given in a lymph node in the groin on 3 occasions, one month apart. As this method takes only eight weeks, it is a much faster and less costly treatment. However, although several studies have shown that the treatment is safe, its efficacy remains the subject of doubt.

    Our pilot study in 2012, with a 3-year follow-up to 2015, showed encouraging results, and was followed by a double-blind randomised study with 72 participants from 2014 to 2018. The research subjects then received treatment with birch and grass pollen extract or one extract and a placebo. Regardless of treatment, symptoms, quality of life and medication consumption improved during the birch and grass pollen seasons in the 3 years after treatment. Increased frequencies of T-regulatory lymphocytes may explain the non-specific effects.

    In 2017 to 2018, we conducted a double-blind study with 38 participants, half of whom received placebo and half, active treatment. In this study, we saw no difference between the treatment groups in the first year after treatment. However, after discontinuation and unblinding in 2019, i.e., two years after treatment, the actively treated group improved in terms of symptoms, and quality of life was improved compared with the placebo group despite less need for medication. T-regulatory lymphocytes increased one year after treatment only in the actively treated group.

    A long-term follow-up of the research subjects from our two larger studies in 2022, i.e., five to eight years after treatment, showed in the double-blind study without a pure placebo that the scores for symptoms, medication use, and quality of life remained as low as after the first three years. In the placebo-controlled study, a statistically significant improvement in symptoms remained during the grass pollen season. Analysing the two studies together, symptom improvement was significant even during the birch pollen season. Thus, although the effect does not seem to diminish, those who did not receive birch, but only grass, needed to use more medication during the birch pollen season in 2022, seven to eight years after treatment. Moreover, those who did not receive grass but only birch needed more medication during the grass pollen season. This may suggest that the non-specific effect begins to wane after seven to eight years.

    Allergy to pollen is a major problem for individuals and society, where symptom-relieving treatment with drugs is not enough for many. They can be helped with immunotherapy, which takes at least three years, is expensive and fraught with side effects. In contrast, intralymphatic immunotherapy involves three injections over eight weeks. Our three studies show that the treatment is safe and indicate that it has a clinical effect up to eight years after treatment. T-regulatory cells appear to be important to the immunological mechanism, leading to tolerance to pollen.

    Delarbeten
    1. Intralymphatic allergen immunotherapy against pollen allergy. A 3-year open follow-up study of 10 patients
    Öppna denna publikation i ny flik eller fönster >>Intralymphatic allergen immunotherapy against pollen allergy. A 3-year open follow-up study of 10 patients
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    2018 (Engelska)Ingår i: Annals of Allergy, Asthma & Immunology, ISSN 1081-1206, E-ISSN 1534-4436, Vol. 121, nr 5, s. 626-627Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    To date, allergen immunotherapy (AIT) is the only treatment that affects the long-term development of allergic rhinoconjunctivitis and induces clinical tolerance primarily by stimulating regulatory T (Treg) cells, attenuating T helper 2 (Th2) responses and synthesis of blocking antibodies1. Conventional AIT with subcutaneous injections, sublingual tablets or drops is effective, but consumes time and resources 2.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2018
    Nyckelord
    Immunotherapy, Intralymphatic, Allergy, Rhinoconjunctivitis, T-cells
    Nationell ämneskategori
    Klinisk medicin
    Identifikatorer
    urn:nbn:se:liu:diva-150594 (URN)10.1016/j.anai.2018.07.010 (DOI)000448665400022 ()30021119 (PubMedID)
    Anmärkning

    Funding agencies: Region Ostergotland; Allergy Center in Linkoping; Medical Research Council of Southeast Sweden (FORSS); Bergh Foundation; Asthma and Allergy Association of Sweden

    Tillgänglig från: 2018-08-28 Skapad: 2018-08-28 Senast uppdaterad: 2023-11-27Bibliografiskt granskad
    2. Intralymphatic immunotherapy with one or two allergens renders similar clinical response in patients with allergic rhinitis due to birch and grass pollen
    Öppna denna publikation i ny flik eller fönster >>Intralymphatic immunotherapy with one or two allergens renders similar clinical response in patients with allergic rhinitis due to birch and grass pollen
    Visa övriga...
    2022 (Engelska)Ingår i: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 52, nr 6, s. 747-759Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Introduction

    There is a need for a fast, efficient and safe way to induce tolerance in patients with severe allergic rhinitis. Intralymphatic immune therapy has been shown to be effective.

    Methods

    Patients with severe birch and timothy allergy were randomized and received three doses of 0.1 ml of birch and 5-grass allergen extracts (10,000 SQ units/ml, ALK-Abello), or birch and placebo or 5-grass and placebo by ultrasound-guided injections into inguinal lymph nodes at monthly intervals. Rhinoconjunctivitis total symptom score, medication score and rhinoconjunctivitis quality of life questionnaire were evaluated before treatment and after each birch and grass pollen season during three subsequent years. Circulating proportions of T helper subsets and allergen-induced cytokine and chemokine production were analysed by flow cytometry and Luminex.

    Results

    The three groups reported fewer symptoms, lower use of medication and improved quality of life during the birch and grass pollen seasons each year after treatment at an almost similar rate independently of treatment with one or two allergens. Mild local pain was the most common adverse event. IgE levels to birch decreased, whereas birch-induced IL-10 secretion increased in all three groups. IgG4 levels to birch and timothy and skin prick test reactivity remained mainly unchanged. Conjunctival challenge tests with timothy extract showed a higher threshold for allergen. In all three groups, regulatory T cell frequencies were increased 3 years after treatment.

    Conclusions

    Intralymphatic immunotherapy with one or two allergens in patients with grass and birch pollen allergy was safe, effective and may be associated with bystander immune modulatory responses.

    Ort, förlag, år, upplaga, sidor
    Chichester, United Kingdom: Wiley-Blackwell Publishing Inc., 2022
    Nyckelord
    allergy; intralymphatic immunotherapy; hypersensitivity; rhinoconjunctivitis immunotherapy; intralymphatic; allergy
    Nationell ämneskategori
    Lungmedicin och allergi
    Identifikatorer
    urn:nbn:se:liu:diva-184407 (URN)10.1111/cea.14138 (DOI)000776517300001 ()35332591 (PubMedID)2-s2.0-85127382771 (Scopus ID)
    Anmärkning

    Funding Agencies: Region Östergotland; Medical Research Council of Southeast Sweden (FORSS); Th Bergh Foundation; Asthma and Allergy Association

    Tillgänglig från: 2022-04-21 Skapad: 2022-04-21 Senast uppdaterad: 2023-11-27Bibliografiskt granskad
    3. Intralymphatic immunotherapy with birch and grass pollen extracts. A randomized double-blind placebo-controlled clinical trial
    Öppna denna publikation i ny flik eller fönster >>Intralymphatic immunotherapy with birch and grass pollen extracts. A randomized double-blind placebo-controlled clinical trial
    Visa övriga...
    2023 (Engelska)Ingår i: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 53, nr 8, s. 809-820Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    IntroductionThere is a need to evaluate the safety and efficacy of intralymphatic immunotherapy (ILIT) for inducing tolerance in patients with allergic rhinitis. MethodsThirty-seven patients with seasonal allergic symptoms to birch and grass pollen and skin prick test >3 mm and/or IgE to birch and timothy >0.35 kU/L were randomized to either ILIT, with three doses of 0.1 mL of birch pollen and 5-grass pollen allergen extracts on aluminium hydroxide (10,000 SQ-U/ml; ALK-Abello) or placebo using ultrasound-guided intralymphatic injections at monthly intervals. Daily combined symptom medical score and rhinoconjunctivitis total symptom score were recorded during the peak pollen seasons the year before and after treatment. Rhinoconjunctivitis total symptom score, medication score and rhinoconjunctivitis quality of life questionnaire were recorded annually starting 2 years after treatment. Circulating proportions of T helper cell subsets and allergen-induced cytokine and chemokine production were analysed using flow cytometry and ELISA. ResultsThere were no differences between the groups related to daily combined symptom medical score the year before and after treatment. Two years after ILIT (after unblinding), the actively treated group reported significantly fewer symptoms, lower medication use and improved quality of life than did the placebo group. After the pollen seasons the year after ILIT, T regulatory cell frequencies and grass-induced IFN-gamma levels increased only in the actively treated group. ConclusionIn this randomized controlled trial, ILIT with birch and grass pollen extract was safe and accompanied by immunological changes. Further studies are required to confirm or refute the efficacy of the treatment.

    Ort, förlag, år, upplaga, sidor
    WILEY, 2023
    Nyckelord
    allergy; hypersensitivity; intralymphatic immunotherapy; rhinoconjunctivitis
    Nationell ämneskategori
    Lungmedicin och allergi
    Identifikatorer
    urn:nbn:se:liu:diva-193405 (URN)10.1111/cea.14307 (DOI)000962776700001 ()37013723 (PubMedID)
    Anmärkning

    Funding Agencies|Astma- och Allergifoerbundet; Region OEstergoetland; Medical Research Council of Southeast Sweden (FORSS); Bergh Foundation

    Tillgänglig från: 2023-05-03 Skapad: 2023-05-03 Senast uppdaterad: 2023-11-27
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  • 2. Beställ onlineKöp publikationen >>
    Abedini, Fereshteh
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    2D and 3D Halftoning for Appearance Reproduction2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.    

    Delarbeten
    1. 3D Halftoning based on Iterative Method Controlling Dot Placement
    Öppna denna publikation i ny flik eller fönster >>3D Halftoning based on Iterative Method Controlling Dot Placement
    2020 (Engelska)Konferensbidrag, Muntlig presentation med publicerat abstract (Refereegranskat)
    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.

    Nyckelord
    3D printing, 3D halftoning, Surface reproduction
    Nationell ämneskategori
    Mediateknik
    Identifikatorer
    urn:nbn:se:liu:diva-171744 (URN)10.2352/ISSN.2169-4451.2020.36.69 (DOI)
    Konferens
    Printing for Fabrication, Online 2020, October 19-21
    Tillgänglig från: 2020-12-01 Skapad: 2020-12-01 Senast uppdaterad: 2023-09-26Bibliografiskt granskad
    2. 3D Surface Structures and 3D Halftoning
    Öppna denna publikation i ny flik eller fönster >>3D Surface Structures and 3D Halftoning
    2020 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Nyckelord
    3D halftoning, Hybrid halftoning, 3D surface structures
    Nationell ämneskategori
    Mediateknik
    Identifikatorer
    urn:nbn:se:liu:diva-170797 (URN)10.2352/ISSN.2169-4451.2020.36.75 (DOI)
    Konferens
    Printing for Fabrication 2020
    Tillgänglig från: 2020-10-22 Skapad: 2020-10-22 Senast uppdaterad: 2023-09-26Bibliografiskt granskad
    3. The Effect of Halftoning on the Appearance of 3D Printed Surfaces
    Öppna denna publikation i ny flik eller fönster >>The Effect of Halftoning on the Appearance of 3D Printed Surfaces
    2021 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Nyckelord
    3D printing, Halftoning, Surface appearance
    Nationell ämneskategori
    Mediateknik
    Identifikatorer
    urn:nbn:se:liu:diva-180696 (URN)
    Konferens
    47th Annual Conference of Iarigai
    Tillgänglig från: 2021-10-29 Skapad: 2021-10-29 Senast uppdaterad: 2023-09-26Bibliografiskt granskad
    4. Structure-Aware Halftoning Using the Iterative Method Controlling the Dot Placement
    Öppna denna publikation i ny flik eller fönster >>Structure-Aware Halftoning Using the Iterative Method Controlling the Dot Placement
    2021 (Engelska)Ingår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 65, nr 6Artikel i tidskrift (Refereegranskat) 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.

    Ort, förlag, år, upplaga, sidor
    I S & T-SOC IMAGING SCIENCE TECHNOLOGY, 2021
    Nyckelord
    Halftoning, Structure-Aware Halftoning, Hough Transform, Image Quality Evaluation
    Nationell ämneskategori
    Mediateknik
    Identifikatorer
    urn:nbn:se:liu:diva-181613 (URN)10.2352/j.imagingsci.technol.2021.65.6.060404 (DOI)000734009600011 ()
    Anmärkning

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

    Tillgänglig från: 2021-12-04 Skapad: 2021-12-04 Senast uppdaterad: 2023-09-26Bibliografiskt granskad
    5. Structure-Aware Color Halftoning with Adaptive Sharpness Control
    Öppna denna publikation i ny flik eller fönster >>Structure-Aware Color Halftoning with Adaptive Sharpness Control
    2022 (Engelska)Ingår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 66, nr 6, artikel-id 060404Artikel i tidskrift (Refereegranskat) 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.

    Ort, förlag, år, upplaga, sidor
    I S & T-SOC IMAGING SCIENCE TECHNOLOGY, 2022
    Nationell ämneskategori
    Mediateknik
    Identifikatorer
    urn:nbn:se:liu:diva-192705 (URN)10.2352/J.ImagingSci.Technol.2022.66.6.060404 (DOI)000939908300011 ()
    Anmärkning

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

    Tillgänglig från: 2023-03-31 Skapad: 2023-03-31 Senast uppdaterad: 2023-09-26
    6. Effect of halftones on printing iridescent colors
    Öppna denna publikation i ny flik eller fönster >>Effect of halftones on printing iridescent colors
    2023 (Engelska)Ingår i: IS&T Electronic Imaging: Color Imaging XXVIII: Displaying, Processng, Hardcopy, and Applications, The Society for Imaging Science and Technology, 2023, Vol. 35, s. 1-6Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Ort, förlag, år, upplaga, sidor
    The Society for Imaging Science and Technology, 2023
    Nationell ämneskategori
    Mediateknik
    Identifikatorer
    urn:nbn:se:liu:diva-197992 (URN)
    Konferens
    IS&T Electronic Imaging
    Tillgänglig från: 2023-09-20 Skapad: 2023-09-20 Senast uppdaterad: 2023-09-26
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  • 3. Beställ onlineKöp publikationen >>
    Ni, Zhongjun
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    A Digitalization Framework for Smart Maintenance of Historic Buildings2023Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Smart underhåll av kulturhistoriska byggnader med digital teknologi och dataanalys underlättar bevarandet av det kulturhistoriska värdet såväl som anpassning för olika användning. Lokalt utplacerade uppkopplade sakernas internet enheter (Internet of Things, IoT) möjliggör realtidsövervakning av miljösensordata. Genom att analysera insamlade data så kan beslutsfattare identifiera och proaktivt hantera potentiella risker i byggnaden. Underhåll av kulturhistoriska byggnader är ett långsiktigt arbete där varje åtgärd kan få långtgående konsekvenser. Digitala verktyg kan därför bidra dels genom bättre historisk spårbarhet, dels genom bättre prediktion av vad som kommer att hända med byggnaden. En lyckad digital transformering kräver stabila och skalbara lagrings- och beräkningsresurser för att organisera och presentera byggnadsdata. Flexibla applikationer med väl integrerad dataanalys är viktigt för att teknologins fulla potential ska kunna nås.

    Denna licentiatavhandling presenterar ett digitaliseringsramverk som adresserar dessa utmaningar genom att integrera IoT, molnberäkning, ontologisk modellering och maskininlärning. IoT-enheterna möjliggör realtidsövervakning av byggnadens status. Användningar en publika molnplattform erbjuder stabila och skalbara resurser för att lagra och analysera data. Ontologi ger ett klart och koncist sätt att organisera och representera byggnadsdata, vilket gör det enklare att förstå hur olika ingående delar påverkar byggnaden. Från detta kan fysikaliskt motsvarande digitala tvillingar skapas. Genom att applicera maskininlärning på dessa tvillingar så kan mönster identifieras som ger beslutsfattaren all nödvändig information för ett smart, väl optimerat underhåll av byggnaden.

    Artikel I och II fokuserar på konceptformulering och validering av principen. Artikel I går igenom metoden som används för att skapa digitala tvillingar av historiska byggnader. Artikel II presenterar en referensimplementation av metoden. Den implementerade lösningen är ett komplett system för datainsamling, dataöverföring genom en edge-plattform och datalagring med Microsoft Azure Cloud. Artikel III presenterar fälttest med det egenutvecklade systemet i tre olika historiska byggnader, nämligen Stadsteatern, Stadsmuseet och Hörsalen i Norrköping, Sverige. Fälttestet verifierar stabiliteten hos systemet när det gäller långsiktig drift för datainsamling. Artikel IV introducerar ontologisk modellering till systemet för att tillhandahålla ett enhetligt format för att organisera och representera byggnadsdata. En fallstudie utfördes i Stadsteatern för att verifiera lösningens användbarhet, det studerades hur antalet besökare påverkar inomhusklimatet och potentiella risker identifierades. Artikel V och VI jämför prestanda hos moderna djupinlärningsmetoder med avseende på förmåga att prognostisera byggnaders energiförbrukning. Artikel V fokuserar på prestanda hos egenutvecklade prediktiva modeller vilka utvärderades i Stadsteatern och Stadsmuseet, som utgör två olika driftsfall. Artikel VI visar vad kombinationen av prediktiva modeller och digitala tvillingar kan göra för att förbättra byggnaders energiprestanda.

    Sammanfattningsvis bidrar denna avhandling till bevarande av kulturhistoriskt viktiga byggnader med ett omfattande digitaliseringsramverk. Ett ramverk som integrerar olika digitala teknologier med en holistisk strategi för att möjliggöra smart underhåll av historiska byggnader.

    Delarbeten
    1. Improving energy efficiency while preserving historic buildings with digital twins and artificial intelligence
    Öppna denna publikation i ny flik eller fönster >>Improving energy efficiency while preserving historic buildings with digital twins and artificial intelligence
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    2021 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This study proposes a digitalization framework for historic buildings. In this framework, advanced techniques, like Internet of Things (IoT), cloud computing, and artificial intelligence (AI), are utilized to create digital twins for historic buildings. A digital twin is a software representation of a physical object. This study uses digital twins to protect, predict, and optimize through analytics of real-time and historical data of selected features. Heterogeneous data of historic buildings, such as indoor environment, energy consumption metering, and outdoor climate, are collected with proper sensors or retrieved from other data sources. Then, these data are periodically uploaded and stored in the database of the cloud platform. Based on these data, AI models are trained through appropriate machine learning algorithms to monitor historic buildings, predict energy consumption, and control energy-consuming equipment autonomously to reach the balance of energy efficiency, building conservation, and human comfort. The cloud-based characteristic of our digitalization framework makes the digital twins developed in this study easy to be transplanted to many other historic buildings in Sweden and other countries.

    Serie
    IOP Conference Series: Earth and Environmental Science, ISSN 1755-1307, E-ISSN 1755-1315
    Nyckelord
    Historic Buildings Preservation; Energy Efficiency Optimization; Digital Twins; Artificial Intelligence; Internet of Things
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:liu:diva-175125 (URN)10.1088/1755-1315/863/1/012041 (DOI)
    Konferens
    SBE21 Sustainable Built Heritage
    Forskningsfinansiär
    Energimyndigheten
    Anmärkning

    Funding agencies: This study has been financially supported by the Swedish Energy Agency within the program of Sparaoch Bevara.

    Tillgänglig från: 2021-04-19 Skapad: 2021-04-19 Senast uppdaterad: 2023-08-31
    2. Link Historic Buildings to Cloud with Internet of Things and Digital Twins
    Öppna denna publikation i ny flik eller fönster >>Link Historic Buildings to Cloud with Internet of Things and Digital Twins
    2022 (Engelska)Ingår i: The 4th International Conference on Energy Efficiency in Historic Buildings, Benediktbeuern, Germany, May 4-5, 2022 / [ed] Ralf Kilian, Sara Saba, Caroline Gietz, Stuttgart: Fraunhofer IRB Verlag, 2022, s. 229-235Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Information and communication technologies (ICTs) help preserve historic buildings and optimize energy efficiency. This study proposes a digitalization framework for historic buildings by utilizing ICTs, such as Internet of Things (IoT), digital twins, and cloud computing. A digital twin is a digital representation of physical world assets that genuinely reflects the properties of real-world objects and processes. In this study, historic buildings are modeled with cloud-based digital twins. Indoor environmental data are collected with locally deployed sensors and ingested to a digital twin in real-time. The digital twin enables decision-makers to remotely monitor the indoor environment of a historic building and actively manipulate actuators to perform maintenance. Empowered by data analytics and artificial intelligence (AI), a digital twin can further simulate and predict state changes in a historic building to reach desired autonomous maintenance and energy saving.

    Ort, förlag, år, upplaga, sidor
    Stuttgart: Fraunhofer IRB Verlag, 2022
    Nyckelord
    Internet of Things, digital twins, cloud computing, historic buildings, energy efficiency
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:liu:diva-188007 (URN)978-3-7388-0779-0 (ISBN)978-3-7388-0780-6 (ISBN)
    Konferens
    The 4th International Conference on Energy Efficiency in Historic Buildings
    Forskningsfinansiär
    Energimyndigheten
    Tillgänglig från: 2022-09-01 Skapad: 2022-09-01 Senast uppdaterad: 2023-08-31
    3. A Sensing System Based on Public Cloud to Monitor Indoor Environment of Historic Buildings
    Öppna denna publikation i ny flik eller fönster >>A Sensing System Based on Public Cloud to Monitor Indoor Environment of Historic Buildings
    2021 (Engelska)Ingår i: Sensors, E-ISSN 1424-8220, Vol. 21, nr 16, artikel-id 5266Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Monitoring the indoor environment of historic buildings helps to identify potential risks, provide guidelines for improving regular maintenance, and preserve cultural artifacts. However, most of the existing monitoring systems proposed for historic buildings are not for general digitization purposes that provide data for smart services employing, e.g., artificial intelligence with machine learning. In addition, considering that preserving historic buildings is a long-term process that demands preventive maintenance, a monitoring system requires stable and scalable storage and computing resources. In this paper, a digitalization framework is proposed for smart preservation of historic buildings. A sensing system following the architecture of this framework is implemented by integrating various advanced digitalization techniques, such as Internet of Things, Edge computing, and Cloud computing. The sensing system realizes remote data collection, enables viewing real-time and historical data, and provides the capability for performing real-time analysis to achieve preventive maintenance of historic buildings in future research. Field testing results show that the implemented sensing system has a 2% end-to-end loss rate for collecting data samples and the loss rate can be decreased to 0.3%. The low loss rate indicates that the proposed sensing system has high stability and meets the requirements for long-term monitoring of historic buildings.

    Ort, förlag, år, upplaga, sidor
    MDPI, 2021
    Nyckelord
    Internet of Things; edge computing; cloud computing; historic buildings; indoor environment
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-178184 (URN)10.3390/s21165266 (DOI)000690008900001 ()34450715 (PubMedID)
    Forskningsfinansiär
    Energimyndigheten
    Anmärkning

    Funding: Swedish Energy AgencySwedish Energy Agency [DNR: 2019-023737]

    Tillgänglig från: 2021-08-11 Skapad: 2021-08-11 Senast uppdaterad: 2023-08-31
    4. Enabling Preventive Conservation of Historic Buildings Through Cloud-based Digital Twins: A Case Study in the City Theatre, Norrköping
    Öppna denna publikation i ny flik eller fönster >>Enabling Preventive Conservation of Historic Buildings Through Cloud-based Digital Twins: A Case Study in the City Theatre, Norrköping
    2022 (Engelska)Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 90924-90939Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Historic buildings require good maintenance to sustain their function and preserve embodied heritage values. Previous studies have demonstrated the benefits of digitalization techniques in improving maintenance and managing threats to historic buildings. However, there still lacks a solution that can consistently organize data collected from historic buildings to reveal operating conditions of historic buildings in real-time and to facilitate various data analytics and simulations. This study aims to provide such a solution to help achieve preventive conservation. The proposed solution integrates Internet of Things and ontology to create digital twins of historic buildings. Internet of Things enables revealing the latest status of historic buildings, while ontology provides a consistent data schema for representing historic buildings. This study also gives a reference implementation by using public cloud services and open-source software libraries, which make it easier to be reused in other historic buildings. To verify the feasibility of the solution, we conducted a case study in the City Theatre, Norrköping, Sweden. The obtained results demonstrate the advantages of digital twins in providing maintenance knowledge and identifying potential risks caused by fluctuations of relative humidity.

    Ort, förlag, år, upplaga, sidor
    Institute of Electrical and Electronics Engineers (IEEE), 2022
    Nyckelord
    digital twin, historic building, indoor environment, Internet of Things
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:liu:diva-188008 (URN)10.1109/access.2022.3202181 (DOI)000850844100001 ()
    Forskningsfinansiär
    Energimyndigheten
    Tillgänglig från: 2022-09-01 Skapad: 2022-09-01 Senast uppdaterad: 2023-08-31
    5. Leveraging Deep Learning and Digital Twins to Improve Energy Performance of Buildings
    Öppna denna publikation i ny flik eller fönster >>Leveraging Deep Learning and Digital Twins to Improve Energy Performance of Buildings
    2023 (Engelska)Ingår i: 2023 IEEE 3rd International Conference on Industrial Electronics for Sustainable Energy Systems (IESES), IEEE, 2023Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Digital transformation in buildings accumulates massive operational data, which calls for smart solutions to utilize these data to improve energy performance. This study has proposed a solution, namely Deep Energy Twin, for integrating deep learning and digital twins to better understand building energy use and identify the potential for improving energy efficiency. Ontology was adopted to create parametric digital twins to provide consistency of data format across different systems in a building. Based on created digital twins and collected data, deep learning methods were used for performing data analytics to identify patterns and provide insights for energy optimization. As a demonstration, a case study was conducted in a public historic building in Norrköping, Sweden, to compare the performance of state-of-the-art deep learning architectures in building energy forecasting.

    Ort, förlag, år, upplaga, sidor
    IEEE, 2023
    Nyckelord
    deep learning, digital twin, building energy forecasting
    Nationell ämneskategori
    Energisystem Byggproduktion Annan data- och informationsvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-198152 (URN)10.1109/ieses53571.2023.10253721 (DOI)979-8-3503-2475-4 (ISBN)979-8-3503-2476-1 (ISBN)
    Konferens
    2023 IEEE 3rd International Conference on Industrial Electronics for Sustainable Energy Systems (IESES)
    Forskningsfinansiär
    Energimyndigheten
    Tillgänglig från: 2023-09-26 Skapad: 2023-09-26 Senast uppdaterad: 2023-09-26
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  • 4. Beställ onlineKöp publikationen >>
    Rönnby, Karl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    A Study of Group 13-Nitride Atomic Layer Deposition: Computational Chemistry Modelling of Atomistic Deposition Processes2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The crystalline solids aluminium nitride (AlN), gallium nitride (GaN) and indium nitride (InN), together with their alloys, are of huge interest in the semiconductor industry. Their bandgaps span an extensive range from 6.0 eV for AlN to 0.7 eV for InN, with GaN in between at a bandgap of 3.6 eV. Thus, with bandgap tuning from infrared (IR) to ultraviolet (UV) they are well suited for photoelectric applications such as light emitting diodes (LED). The higher bandgaps of AlN and GaN compared to that of silicon (1.1 eV) makes them suitable for high power applications while the high electron mobility of InN makes it attractive for high frequency transistors. Since aluminium, gallium, and indium belong to group 13, their nitrides are termed group 13-nitrides (13Ns).  

    The deposition techniques chemical vapor deposition (CVD) and atomic layer deposition (ALD) can be used to produce thin films upon a substrate through reactions by suitable precursor molecules in the gas phase or at the surface. These techniques have successfully deposited thin films of 13Ns using commercially available precursors, e.g., trimethyl aluminium (TMA), trimethyl gallium (TMG) and trimethyl indium (TMI) as metal precursor and ammonia (NH3) as nitrogen precursor. However, the chemistry between these precursors is not well developed, as evidenced by the large nonstoichiometric ratio between the metal and nitrogen precursors, in the order of 1:100-1:105. This is not sustainable for mass production of these materials, as significant amounts of precursor gas are wasted and must either be cleaned from the exhaust or be released into the atmosphere. In my thesis, the gas phase decomposition and the surface adsorption of these precursors and alternatives are investigated by computational approaches.  

    Gas phase decomposition of ammonia is investigated by kinetic modelling at relevant temperature and pressures. At these conditions, a very small fraction of the initial ammonia molecules can decompose within the expected residence time for the gases in the process. The conclusion is that the low reactivity of ammonia is intrinsic and is not due to decomposition into unreactive nitrogen and hydrogen gas. Methylamines as alternative nitrogen precursors are explored for CVD of GaN. Although these are more reactive in the gas phase, their lower surface reactivity compared to ammonia limits their use as a replacement for ammonia in 13N CVD. The origin of the surface reactivity of ammonia in thermal ALD of AlN and GaN, in comparison to the lack of reactivity on InN, is explored. Comparing GaN and InN surface chemistry, the surface adsorption process on InN is less favourable than on GaN as well as being many orders of magnitude slower, indicating that the lack of any reported thermal ALD process on InN arises from the low reactivity of ammonia towards the InN surface.  

    The resulting surface terminations after ammonia dosing determines how the metal precursors adsorb and react. A series of nitrogen rich surface terminations of the 13Ns is investigated by density functional theory (DFT) modelling and their stability and prevalence at different temperature and pressures are determined from statistical thermodynamics. At low temperatures the surfaces are terminated by hydrogen bonding amino groups while at high temperatures the surface is bare, with the transition temperature between the two structures decreasing from AlN to GaN to InN. TMA can adsorb onto the amino terminated surface and loses ligands by decomposing. Subsequent TMA molecules are found to decompose in two ways depending on how close it adsorbed to an already adsorbed and decomposed molecule.  

    A suitable alternative class of metal precursor for 13N ALD are molecules with nitrogen to metal bonds, such as formamidinates, amidinates, trisguanidinates, or triazenides. Ammonia will have an easier process to break the weaker metal nitrogen bond compared to a metal carbon bond. The gas phase decomposition of a trisguanidinate precursor is investigated but it is shown to be likely to decompose during volatilization, limiting its use as an InN ALD precursor.  

    My thesis consists of detailed atomistic simulations of the deposition of AlN, GaN and InN thin films. The simulations in cooperation with experimental work are used to elucidate the detailed atomistic mechanisms occurring during the process. It gives insight into the shortcomings of the current processes and precursors and can be used as a basis for how to improve them, rendering the 13N a suitable material in a sustainable large-scale production for a variety of semiconductor applications. 

    Delarbeten
    1. Kinetic modeling of ammonia decomposition at chemical vapor deposition conditions
    Öppna denna publikation i ny flik eller fönster >>Kinetic modeling of ammonia decomposition at chemical vapor deposition conditions
    2020 (Engelska)Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, nr 5, artikel-id 050402Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Kinetic modeling has been used to study the decomposition chemistry of ammonia at a wide range of temperatures, pressures, concentrations, and carrier gases mimicking the conditions in chemical vapor deposition (CVD) of metal nitrides. The modeling shows that only a small fraction of the ammonia molecules will decompose at most conditions studied. This suggests that the fact that the high NH3 to metal ratios often employed in CVD is due to the very low amount of reactive decomposition products being formed rather than due to rapid decomposition of ammonia into stable dinitrogen and dihydrogen as suggested by purely thermodynamic equilibrium models.

    Ort, förlag, år, upplaga, sidor
    A V S AMER INST PHYSICS, 2020
    Nationell ämneskategori
    Oorganisk kemi
    Identifikatorer
    urn:nbn:se:liu:diva-169219 (URN)10.1116/6.0000369 (DOI)000561391400001 ()
    Anmärkning

    Funding Agencies|Swedish foundation for Strategic Research through the project "Time-resolved low temperature CVD for III-nitrides" [SSF-RMA 15-0018]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at the Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]; Swedish Research Council (VR)Swedish Research Council

    Tillgänglig från: 2020-09-12 Skapad: 2020-09-12 Senast uppdaterad: 2023-02-24
    2. Methylamines as Nitrogen Precursors in Chemical Vapor Deposition of Gallium Nitride
    Öppna denna publikation i ny flik eller fönster >>Methylamines as Nitrogen Precursors in Chemical Vapor Deposition of Gallium Nitride
    Visa övriga...
    2019 (Engelska)Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, nr 11, s. 6701-6710Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Chemical vapor deposition (CVD) is one of the most important techniques for depositing thin films of the group 13 nitrides (13-Ns), AIN, GaN, InN, and their alloys, for electronic device applications. The standard CVD chemistry for 13-Ns uses ammonia as the nitrogen precursor; however, this gives an inefficient CVD chemistry, forcing N/13 ratios of 100/1 or more. Here, we investigate the hypothesis that replacing the N-H bonds in ammonia with weaker N-C bonds in methylamines will permit better CVD chemistry, allowing lower CVD temperatures and an improved N/13 ratio. Quantum chemical computations show that while the methylamines have a more reactive gas-phase chemistry, ammonia has a more reactive surface chemistry. CVD experiments using methylamines failed to deposit a continuous film, while instead micrometer-sized gallium droplets were deposited. This study shows that the nitrogen surface chemistry is most likely more important to be considered than the gas-phase chemistry when searching for better nitrogen precursors for 13-N CVD.

    Ort, förlag, år, upplaga, sidor
    AMER CHEMICAL SOC, 2019
    Nationell ämneskategori
    Oorganisk kemi
    Identifikatorer
    urn:nbn:se:liu:diva-156198 (URN)10.1021/acs.jpcc.9b00482 (DOI)000462260700044 ()
    Anmärkning

    Funding Agencies|Swedish foundation for Strategic Research [SSF-RMA 15-0018]; Vinnova VINNMER Marie Curie incoming mobility program [2015-03714]; COST (European Cooperation in Science and Technology) [MP1402]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]

    Tillgänglig från: 2019-04-09 Skapad: 2019-04-09 Senast uppdaterad: 2023-02-24
    3. On the limitations of thermal atomic layer deposition of InN using ammonia
    Öppna denna publikation i ny flik eller fönster >>On the limitations of thermal atomic layer deposition of InN using ammonia
    2023 (Engelska)Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 2, artikel-id 020401Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Chemical vapor deposition of indium nitride (InN) is severely limited by the low thermal stability of the material, and, thus, low-temperature deposition processes such as atomic layer deposition (ALD) are needed to deposit InN films. The two chemically and structurally closely related materials—aluminum nitride and gallium nitride (GaN)—can be deposited by both plasma and thermal ALD, with ammonia (NH3) as a nitrogen precursor in thermal processes. InN, however, can only be deposited using plasma ALD, indicating that there might be a limitation to thermal ALD with NH3 for InN. We use quantum-chemical density functional theory calculations to compare the adsorption process of NH3 on GaN and InN to investigate if differences in the process could account for the lack of thermal ALD of InN. Our findings show a similar reactive adsorption mechanism on both materials, in which NH3 could adsorb onto a vacant site left by a desorbing methyl group from the surfaces. The difference in energy barrier for this adsorption indicates that the process is many magnitudes slower on InN compared to GaN. Slow kinetics would hinder NH3 from reactively adsorbing onto InN in the timeframe of the ALD growth process and, thus, limit the availability of a thermal ALD process.

    Ort, förlag, år, upplaga, sidor
    American Vacuum Society, 2023
    Nationell ämneskategori
    Materialkemi
    Identifikatorer
    urn:nbn:se:liu:diva-191934 (URN)10.1116/6.0002355 (DOI)000936907900001 ()
    Anmärkning

    Funding agencies: This project was funded by the Swedish Foundation for Strategic Research through the project “Time-resolved low temperature CVD for III-nitrides” (No. SSF-RMA 15-0018). L.O. acknowledges financial support from the Swedish Research Council (VR). Supercomputing resources were provided by the Swedish National Infrastructure for Computing (SNIC) and the Swedish National Supercomputer Centre (NSC).

    Tillgänglig från: 2023-02-24 Skapad: 2023-02-24 Senast uppdaterad: 2023-03-21Bibliografiskt granskad
    4. Surface Structures from NH(3) Chemisorption in CVD and ALD of AlN, GaN, and InN Films
    Öppna denna publikation i ny flik eller fönster >>Surface Structures from NH(3) Chemisorption in CVD and ALD of AlN, GaN, and InN Films
    2022 (Engelska)Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 126, nr 13, s. 5885-5895Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Aluminum nitride (AlN), gallium nitride (GaN),and indium nitride (InN) form a family of technologicallyimportant semiconductors of high importance to light-emittingdiodes and high-frequency electronics. Although thinfilms of thesematerials are routinely manufactured by chemical vapor deposition(CVD) and atomic layer deposition (ALD), these methods are farfrom optimal and knowledge of the underlying chemical processesis lacking. In this work, we performed ab initio investigations of thesurface coverage of these materials under an ammonia-richatmosphere. Periodic density functional theory calculations wereused to test the probable surface structures, and their electronicand thermal energies were used to calculate their contribution tothe surface composition under the temperature and pressureconditions relevant for CVD and ALD processes of these materials. The results show similarities between the group of materials witha similar NHxsurface structure present for all three. Comparison of the coverage showed that at low growth temperatures, thesurface is expected to be covered by NH2, while at high temperatures, most surface sites would be vacant. The surface structureswere all found to be the most stable on AlN and least stable on InN. These results are important for further investigations of thematerial growth mechanisms.

    Ort, förlag, år, upplaga, sidor
    American Chemical Society (ACS), 2022
    Nationell ämneskategori
    Materialkemi
    Identifikatorer
    urn:nbn:se:liu:diva-184838 (URN)10.1021/acs.jpcc.2c00510 (DOI)000786685900008 ()
    Anmärkning

    Funding Agencies|Swedish foundation for Strategic Research through the project "Time-resolved low temperature CVD for III-nitrides" [SSF-RMA 15-0018]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at the Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]; Swedish Research Council (VR)Swedish Research Council

    Tillgänglig från: 2022-05-12 Skapad: 2022-05-12 Senast uppdaterad: 2023-02-24
    5. Thermal study of an indium trisguanidinate as a possible indium nitride precursor
    Öppna denna publikation i ny flik eller fönster >>Thermal study of an indium trisguanidinate as a possible indium nitride precursor
    Visa övriga...
    2018 (Engelska)Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 36, nr 1, artikel-id 01A101Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Tris-N,N,-dimethyl-N,N -diisopropylguanidinatoindium(III) has been investigated both as a chemical vapor deposition precursor and an atomic layer deposition precursor. Although deposition was satisfactory in both cases, each report showed some anomalies in the thermal stability of this compound, warrenting further investigation, which is reported herein. The compound was found to decompose to produce diisopropylcarbodiimide both by computational modeling and solution phase nuclear magnetic resonance characterization. The decomposition was shown to have an onset at approximately 120 degrees C and had a constant rate of decomposition from 150 to 180 degrees C. The ultimate decomposition product was suspected to be bisdimethylamidoN, N,-dimethyl-N,N -diisopropylguanidinato-indium(III), which appeared to be an intractable, nonvolatile polymer. Published by the AVS.

    Ort, förlag, år, upplaga, sidor
    A V S AMER INST PHYSICS, 2018
    Nationell ämneskategori
    Oorganisk kemi
    Identifikatorer
    urn:nbn:se:liu:diva-144248 (URN)10.1116/1.5002634 (DOI)000418961400001 ()
    Anmärkning

    Funding Agencies|Swedish foundation for Strategic Research through the project "Time-resolved low temperature CVD for III-nitrides" [SSF-RMA15-0018]; COST Action [MP1402]; COST (European Cooperation in Science and Technology); Vinnova VINNMER Marie Curie incoming mobility program (Vinnova Grant) [2015-03714]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]; Swedish Research Council (VR Grant) [2016-05137_4]; Wenner-Gren foundations

    Tillgänglig från: 2018-01-12 Skapad: 2018-01-12 Senast uppdaterad: 2023-02-24
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  • 5. Beställ onlineKöp publikationen >>
    Knöös Franzén, Ludvig
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    A System of Systems View in Early Product Development: An Ontology-Based Approach2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Konceptet system-av-system blir allt vanligare och relevant i många tekniska tillämpningsområden. Dagens högt sammanlänkade värld innebär att fler och fler system har beroenden med andra system. Detta ökande antal av ömsesidiga beroenden resulterar i nya nivåer av komplexitet som måste hanteras i den tidiga utvecklingen av nya produkter. Olika synsätt måste också hanteras för att förstå de många skikt som ett system-av-system består av och dess omgivande omständigheter. En ständigt föränderlig framtid resulterar i osäkerhet om den operativa miljön men även andra aspekter, såsom tillgängliga teknologier, vilket komplicerar saken ytterligare. Traditionella metoder för tidig produktutveckling kan användas i viss utsträckning, men komplexiteten, skalan och det stora antalet sammankopplingar i system-av-system kräver ett mer holistiskt synsätt för att skapa en tidig förståelse av problemet, designrymden och andra inblandade aspekter.

    Denna avhandling syftar till att presentera en metod som har utvecklats för att möta efterfrågan på en mer holistisk system-av-system-vy i tidig produktutveckling. Sammantaget består metoden av fyra delar som tillsammans visar hur designrymder för system-av-system kan genereras och senare bearbetas för att hitta lämpliga lösningar. Sök- och räddningsinsatser har använts som exempel på system-av-system genom hela detta arbete och i utvecklingen av den presenterade metoden. De två första delarna av metoden är baserade på arkitekturramverk och ontologier med beskrivningslogiska resonemangsförmågor. Ett arkitekturramverk används här för att bryta ned system-av-system-behov i funktioner som ska uppfyllas av involverade system. Ontologier används därefter för att representera resultatet och de resulterande system-av-system-designrymderna med involverade entiteter och deras relationer. Beskrivningslogiska resonemang kan sedan användas för att bearbeta de tillgängliga designrymderna och föreslå lämpliga system-av-system-lösningar. De två sista delarna av metoden bygger på en konceptutforsknings och uppskattningsmetod tillsammans med visuell analysteknik. Tillvägagångssättet illustrerar hur individuella systemkoncept kan estimeras från en ontologirepresenterad designrymd, och hur visuell analysteknik kan användas för att utforska olika system-av-system-perspektiv i ett tidigt skede. Baserat på resultaten av den presenterade metoden bidrar denna avhandling med en helhetssyn på tidig produktutveckling utifrån en system-av-system-vy.  

    Delarbeten
    1. An Ontological Approach to System of Systems Engineering in Product Development
    Öppna denna publikation i ny flik eller fönster >>An Ontological Approach to System of Systems Engineering in Product Development
    2019 (Engelska)Ingår i: Linköping Electronic Conference Proceedings 162 (2019) / [ed] Dr. Ingo Staack and Prof. Petter Krus, Linköping: Linköping University Electronic Press, 2019, Vol. 162:4, s. 35-44Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper presents an approach to system-of-systems engineering for product development with the use of ontology. A proposed method for building as well as using ontology to generate and explore system-of-systems design spaces based on identified system-of-system needs is presented. The method is largely built to cover the first levels of related work, where a process for system of systems in the context of product development is introduced. Within this work, it is shown that scenarios for a system-of-systems can be used to identify needs and subsequently the system-of-systems capabilities that fulfils them. The allocation of capabilities to possible constituent systems is used to show the available design space. The proposed method of this paper therefore addresses these initial challenges and provides a framework for approaching the system-of-systems design space creation using ontology. A case study is used to test the method on a fictitious search and rescue scenario based on available resources and information from the Swedish Maritime Administration. The case study shows that a representation of a system-of-systems scenario can be created in an ontology using the method. The ontology provides a representation of the involved entities from the fictitious scenario and their existing relationships. Defined ontology classes containing conditions are used to represent the identified needs for the system-of-systems. The invocation of a description logic reasoner is subsequently used to classify and create an inferred ontology where the available system-of-systems solutions are represented as sub-classes and individuals of the defined classes representing the needs. Finally, several classes representing different possible system-of-systems needs are used to explore the available design space and to identify the most persistent solutions of the case study.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2019
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 162
    Nyckelord
    system-of-systems, ontology, description logic reasoning, design space generation
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-175761 (URN)10.3384/ecp19162004 (DOI)978-91-7519-006-8 (ISBN)
    Konferens
    Proceedings of the 10th Aerospace Technology Congress
    Tillgänglig från: 2021-05-19 Skapad: 2021-05-19 Senast uppdaterad: 2023-05-11Bibliografiskt granskad
    2. A System of Systems Approach for Search and Rescue Missions
    Öppna denna publikation i ny flik eller fönster >>A System of Systems Approach for Search and Rescue Missions
    Visa övriga...
    2020 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    System-of-Systems Engineering (SoSE) has become a constantly growing field within product development for complex systems. Systems are becoming more and more connected with other systems and the operational environment in general. This takes the development process to new levels of complexity where high degrees of uncertainties are expected due to ever occurring changes in the operational environment, and other external factors such as politics, economy, and technology. This creates a need of being able to understand the influence of changes early in the development process and to facilitate the systems? perseverance. The focus of the development shifts from fulfilling specific requirements, to being able to meet needs and deliver capabilities over time. Additionally, modeling and simulation for complex systems and System-of-Systems (SoS) becomes a valued alternative to the economically prohibited and almost impossible prototype testing. In consideration of this problem, the presented work introduces a method for both modeling and simulation of a SoS. The method uses ontology with description logic reasoning to derive and narrow down a SoS design space which is further analyzed using Agent Based Simulation (ABS). A Search and Rescue (SAR) scenario is used as a case study to test the method. Measures of Effectiveness (MoE), based on the time it takes to find a rescue subject and the cost of doing so, are used to evaluate the SoS performances. The presented method is envisioned to be used early in the development of complex systems and SoS to increase the overall understanding of them.

    Ort, förlag, år, upplaga, sidor
    American Institute of Aeronautics and Astronautics, 2020
    Nyckelord
    Model Based System Engineering, Unified Modeling Language, Web Ontology Language, Extensible Markup Language, Ocean Currents, Helicopters, Air Vehicle, Probability Density Functions, Cyber Physical System
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-175763 (URN)10.2514/6.2020-0455 (DOI)
    Konferens
    AIAA Scitech 2020 Forum
    Tillgänglig från: 2021-05-19 Skapad: 2021-05-19 Senast uppdaterad: 2023-11-02Bibliografiskt granskad
    3. A Breakdown of System of Systems Needs Using Architecture Frameworks, Ontologies and Description Logic Reasoning
    Öppna denna publikation i ny flik eller fönster >>A Breakdown of System of Systems Needs Using Architecture Frameworks, Ontologies and Description Logic Reasoning
    Visa övriga...
    2021 (Engelska)Ingår i: Aerospace, E-ISSN 2226-4310, Vol. 8, nr 4Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Aerospace systems are connected with the operational environment and other systems in general. The focus in aerospace product development is consequently shifting from a singular system perspective to a System-of-Systems (SoS) perspective. This increasing complexity gives rise to new levels of uncertainty that must be understood and managed to produce aerospace solutions for an ever-changing future. This paper presents an approach to using architecture frameworks, and ontologies with description logic reasoning capabilities, to break down SoS needs into required capabilities and functions. The intention of this approach is to provide a consistent way of obtaining the functions to be realized in order to meet the overarching capabilities and needs of an SoS. The breakdown with an architecture framework results in an initial design space representation of functions to be performed. The captured knowledge is then represented in an ontology with description logic reasoning capabilities, which provides a more flexible way to expand and process the initial design space representation obtained from the architecture framework. The proposed approach is ultimately tested in a search and rescue case study, partly based on the operations of the Swedish Maritime Administration. The results show that it is possible to break down SoS needs in a consistent way and that ontology with description logic reasoning can be used to process the captured knowledge to both expand and reduce an available design space representation.

    Ort, förlag, år, upplaga, sidor
    MDPI, 2021
    Nyckelord
    system of systems, systems engineering, aerospace systems, architecture framework, ontology, description logic reasoning, search and rescue
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-175765 (URN)10.3390/aerospace8040118 (DOI)000642619100001 ()
    Anmärkning

    Funding: Swedish Innovation Agency (VINNOVA)Vinnova [NFFP7/2017-04838]

    Tillgänglig från: 2021-05-19 Skapad: 2021-05-19 Senast uppdaterad: 2023-05-11Bibliografiskt granskad
    4. Ontology-Represented Design Space Processing
    Öppna denna publikation i ny flik eller fönster >>Ontology-Represented Design Space Processing
    Visa övriga...
    2021 (Engelska)Ingår i: AIAA AVIATION 2021 Forum, August 2-6, 2021, VIRTUAL EVENT, USA: American Institute of Aeronautics and Astronautics, 2021Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper presents a method for generating a design space intended for aircraft design with the use of ontologies. Aircraft design, seen from a System-of-Systems (SoS) perspective, gives an idea of the complicated relationships and complexities that need to be managed and understood to develop suitable systems for an ever-changing future. Holistic SoS analyzes are used to investigate customer and stakeholder needs that then can be broken down into capabilities and subsequently functions to be performed by involved Constituent Systems (CS), sub-systems and system elements. Ontologies with description logic reasoning capabilities are then used to represent the outcome of the breakdown. An ontology development and integration process can afterwards be used to merge different ontologies together and by that map the derived functions to means that can implement them. This results in an available SoS design space that can be further processed using a description logic reasoner. The outcome of the proposed method is a reduced available design space of functions to be performed and their respective design alternatives. Search and Rescue (SAR) operations based on the Swedish Maritime Administration (SMA) are used as a case study to test the proposed method and to illustrate how it can be utilized. At the end, a design space of alternatives for a new type of search aircraft is generated with ontology and description logic reasoning.

    Ort, förlag, år, upplaga, sidor
    USA: American Institute of Aeronautics and Astronautics, 2021
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-191925 (URN)10.2514/6.2021-2426 (DOI)
    Konferens
    AIAA Aviation
    Projekt
    System-of-Systems Trade Space Exploration (S2TEP)
    Forskningsfinansiär
    Vinnova, NFFP7/ 2017-04838
    Tillgänglig från: 2023-02-23 Skapad: 2023-02-23 Senast uppdaterad: 2023-05-11
    5. Exploring the Impact of Model Fidelity Through Interactive Visualizations for System of Systems
    Öppna denna publikation i ny flik eller fönster >>Exploring the Impact of Model Fidelity Through Interactive Visualizations for System of Systems
    Visa övriga...
    2022 (Engelska)Ingår i: AIAA SciTech 2022 Forum, January 3-7, 2022, San Diego, CA & Virtual, USA: American Institute of Aeronautics and Astronautics, 2022Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Studying Systems of Systems (SoS) in relation to Measures of Effectiveness (MoE) is a difficult task. This is due to that SoSs include several system levels and operate in changing environments. There are also computational challenges related to modeling and simulation of SoSs and it is difficult to predict behaviors. Therefore, choosing model fidelity for system models and assessing their impact on MoE is of high relevance to the field. This paper illustrates an approach to modeling and simulation for SoSs that can be used to assess the impact of scenario parameters and to explore when level of fidelity on system level affects the MoE. This is made through a case study based on Search and Rescue (SAR) operations where a Design Of Experiments (DOE) of scenario parameters is performed and simulations of each scenario experiment is performed. The case study shows how Agent Based Simulations (ABS) can be used to obtain the MoE for different SAR missions and how the choice of model fidelity for one of the aircraft’s sensors has different effects for various scenarios. Additionally, a Visual Analytics (VA) approach is introduced and used to create a dashboard for visualizing the obtained simulation results in an interactive way. This allows users to make explorations on the resulting data and see how different scenarios influence the performance of each SoS. Furthermore, the results show that changes in scenario parameters impacts the MoE and that this is difficult to predict, at least using a quantitative method. The results point to the importance of exploration for both the scenario, using an interactive dashboard, but also to the importance of exploring the simulation model to study emerging phenomenon. The results of this approach have raised questions regarding if a more qualitative approach of studying SoSs could be beneficial to study MoE for SoSs and if inspiration could be transferred from a more scientific point of view of systems.

    Ort, förlag, år, upplaga, sidor
    USA: American Institute of Aeronautics and Astronautics, 2022
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-191926 (URN)10.2514/6.2022-1467 (DOI)
    Konferens
    AIAA SCITECH Forum
    Projekt
    System-of-Systems Trade Space Exploration (S2TEP)
    Forskningsfinansiär
    Vinnova, NFFP7/ 2017-04838
    Tillgänglig från: 2023-02-23 Skapad: 2023-02-23 Senast uppdaterad: 2023-11-02
    6. Ontology-Assisted Aircraft Concept Generation
    Öppna denna publikation i ny flik eller fönster >>Ontology-Assisted Aircraft Concept Generation
    2022 (Engelska)Ingår i: 33rd Congress of the International Council of the Aeronautical Sciences, Stockholm, Sweden, 2022Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper presents a method for generating a geometrical representation of a concept aircraft from an ontology description. An ontology is used as an overarching knowledge base where entities, such as required functions, their design alternatives, and requirements can be represented. Description logic reasoning is then used to process the available design space and generate suitable concepts to fulfil desired functions, as well as indicate suitable approaches for a subsequent sizing procedure. As ontology representations are limited in terms of numerical calculation capabilities, the obtained concept information must be extracted for additional processing. Further investigations, such as statistical analyses, are consequently performed in order to expand the available information of the concept generated from the ontology. This expansion is performed to obtain estimates of required inputs for a continued geometrical sizing procedure. The outcome of the method is an estimation of the concept’s geometry and its characteristics. This information can from here be reintroduced into the ontology representation for further processing and to expand the original knowledge base. A case study is introduced to test the proposed method and to show how it can be used to estimate the characteristics of an already existing aircraft from basic requirements and configuration details. The results from the method and sizing are also compared with publicly available data for the reference aircraft to see how accurate the estimates were.

    Ort, förlag, år, upplaga, sidor
    Stockholm, Sweden: , 2022
    Nyckelord
    Ontology, Aircraft Conceptual Design, Singular Value Decomposition, Geometry
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-191927 (URN)
    Konferens
    ICAS2022, Stockholm, Sweden, 4-9 September, 2022
    Projekt
    System-of-Systems Trade Space Exploration (S2TEP)
    Tillgänglig från: 2023-02-23 Skapad: 2023-02-23 Senast uppdaterad: 2023-05-11Bibliografiskt granskad
    7. Optimization Framework for Early Conceptual Design of Helicopters
    Öppna denna publikation i ny flik eller fönster >>Optimization Framework for Early Conceptual Design of Helicopters
    2022 (Engelska)Ingår i: Aerospace, ISSN 2226-4310, Vol. 9, nr 10, artikel-id 598Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This work illustrates how a proposed method can be used to create optimization frameworks for early conceptual design studies and to increase overall knowledge at an early design stage. The method is intended to facilitate concept selection in challenging domains that typically involve multidisciplinary design problems with contradictory requirements. The main focus of the work presented here is on the conceptual design of helicopters; however, the method is intended to be applicable to early design studies in other domains as well. In short, statistics about existing helicopters are collected and compiled to provide a basis for various regression analyses. The purpose of this is to unravel relationships in the data and to obtain simple estimation models from statistical regressions that can be used in conjunction with existing formulas and equations to generate an initial helicopter design estimate. Models for each discipline, such as aerodynamics, are then created using the outcomes of the regression analyses and existing equations. Lastly, the method is used to define a multidisciplinary design optimization framework incorporating all the models obtained from the different disciplines. A case study based on search and rescue operations is used to test the proposed framework in order to obtain possible first suggestions for the baseline design of a new general-purpose search and rescue helicopter.

    Ort, förlag, år, upplaga, sidor
    MDPI, 2022
    Nyckelord
    symbolic regression; optimization; conceptual design; genetic algorithm; design of experiments; helicopter statistics
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-189789 (URN)10.3390/aerospace9100598 (DOI)000872085100001 ()
    Anmärkning

    Funding Agencies|Swedish Innovation Agency (VINNOVA) [NFFP7/2017-04838]

    Tillgänglig från: 2022-11-08 Skapad: 2022-11-08 Senast uppdaterad: 2023-05-11
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  • 6. Beställ onlineKöp publikationen >>
    Linge, Jennifer
    Linköpings universitet, Institutionen för hälsa, medicin och vård, Avdelningen för diagnostik och specialistmedicin. Linköpings universitet, Medicinska fakulteten.
    Adverse Muscle Composition: Revisiting Sarcopenia in General Population and Liver Disease using Magnetic Resonance Imaging2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Sarkopeni - från grekiskans 'sarx' (kött) och 'penia' (förlust) - syftade, när uttrycket myntades 1989, till förlust av muskelmassa och funktion i samband med åldrande. En sådan definition är inte speciellt praktiskt för studerandet av sarkopeni då den innebär att alla har (till olika grad) sarkopeni. Tidiga (praktiskt tillämpbara) definitioner av sarkopeni fokuserade på identifiering av låg muskelmassa men senare inkluderar även krav på låg muskelstyrka. Studier av sarkopeni som använt dessa definitioner har visat att muskelförtvining är intensifierad inom metabola sjukdomar och än mer aggressiv vid terminal sjukdom. Trots detta är det fortfarande okänt om sarkopeni accelererar utvecklingen av andra sjukdomar eller tvärt om. Det är dock tydligt att individer med sarkopeni och samsjuklighet är mer sårbara än andra och har större vårdbehov.

    Hos individer med svår leversjukdom har nedsatt muskelhälsa bland annat kopplats till högre sjuklighet och dödlighet samt visats påverka resultatet efter levertransplantation. Därför anses sarkopeni vara en viktig faktor som bör övervägas vid patientbeslut och interventioner för patienter som utvärderas för levertransplantation. Vid tidigare faser av leversjukdom är förståelsen för sarkopeni mer begränsad och tillståndet är sällan uppmärksammat inom vården. En utmaning är den höga förekomsten av obesitas inom sjukdomar (så som fettlever eller diabetes) som kan föregå mer avancerad sjukdom. På grund av större kroppsstorlek, behöver individer med obesitas mer muskelmassa för att bibehålla rörlighet. Därför behövs en högre tröskel för vad som anses vara 'låg muskelmassa', eller alternativt ett mått på muskelmassa som är korrigerat för kroppsstorlek.

    Den här avhandlingen börjar med att tillämpa den europeiska definitionen av sarkopeni på 10,000 frivilliga deltagare från UK Biobank med åldern 44-78. Det visades att dagens metoder för korrigering av kroppsstorlek inte fungerade, vilket ledde till underdiagnostisering av sarkopeni hos individer med övervikt och obesitas.

    Därför utvecklades ett mer individualiserat mått på muskelvolym, vilket kunde användas oberoende av kroppsstorlek. Syftet var att beskriva hur mycket någon avviker från förväntad muskelvolym och indikera huruvida de har 'tillräcklig' muskelvolym - ett z-score för muskelvolym.

    Muskelvolymen mättes med hjälp av magnetresonanstomografi (MR) och från samma bilder mättes även fettinfiltration (vilket indikerar muskelkvalitet). De första resultaten indikerade att både z-score och fettinfiltration var kopplade till funktion och hospitalisering, samt att de mest sårbara individerna skulle kunna identifieras genom att kombinera zscore och fettinfiltration. Därför föreslogs trösklar för att identifiera vad som på engelska kallades 'adverse muscle composition' - en 'ogynnsam muskelsammansättning' - definierad av låg z-score kombinerat med hög fettinfiltration.

    Följande studier undersökte hur adverse muscle composition var kopplat till metabola sjukdomar, muskelfunktion och dödlighet hos studiedeltagare i UK Biobank samt bland dem med fettleversjukdom. Studierna visade att adverse muscle composition var kopplad till ökad sjuklighet och dödlighet oberoende av muskelfunktion och indikerade att kunskap om muskelsammansättning skulle kunna användas för att identifiera hög- respektive lågriskpatienter inom heterogena sjukdomar så som fettlever.

    Idag utvärderas metoden för att beskriva muskelsammansättning och diagnostik av adverse muscle composition för användning inom vården vid behandling av leversvikt och inför levertransplantation genom kliniska studier både i Europa och Nordamerika.

    Delarbeten
    1. On the Definition of Sarcopenia in the Presence of Aging and Obesity-Initial Results from UK Biobank
    Öppna denna publikation i ny flik eller fönster >>On the Definition of Sarcopenia in the Presence of Aging and Obesity-Initial Results from UK Biobank
    2020 (Engelska)Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences, ISSN 1079-5006, E-ISSN 1758-535X, Vol. 75, nr 7, s. 1309-1316Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    BACKGROUND: Current consensus is to combine a functional measure with muscle quantity to assess/confirm sarcopenia. However, the proper body size adjustment for muscle quantity is debated and sarcopenia in obesity is not well described. Further, functional measures are not muscle-specific or sensitive to etiology, and can be confounded by, for example, fitness/pain. For effective detection/treatment/follow-up, muscle-specific biomarkers linked to function are needed.

    METHODS: Nine thousand six hundred and fifteen participants were included and current sarcopenia thresholds (EWGSOP2: DXA, hand grip strength) applied to investigate prevalence. Fat-tissue free muscle volume (FFMV) and muscle fat infiltration (MFI) were quantified through magnetic resonance imaging (MRI) and sex-and-body mass index (BMI)-matched virtual control groups (VCGs) were used to extract each participant's FFMV/height2 z-score (FFMVVCG). The value of combining FFMVVCG and MFI was investigated through hospital nights, hand grip strength, stair climbing, walking pace, and falls.

    RESULTS: Current thresholds showed decreased sarcopenia prevalence with increased BMI (underweight 8.5%/normal weight 4.3%/overweight 1.1%/obesity 0.1%). Contrary, the prevalence of low function increased with increasing BMI. Previously proposed body size adjustments (division by height2/weight/BMI) introduced body size correlations of larger/similar magnitude than before. VCG adjustment achieved normalization and strengthened associations with hospitalization/function. Hospital nights, low hand grip strength, slow walking pace, and no stair climbing were positively associated with MFI (p < .05) and negatively associated with FFMVVCG (p < .01). Only MFI was associated with falls (p < .01). FFMVVCG and MFI combined resulted in highest diagnostic performance detecting low function.

    CONCLUSIONS: VCG-adjusted FFMV enables proper sarcopenia assessment across BMI classes and strengthened the link to function. MFI and FFMV combined provides a more complete, muscle-specific description linked to function enabling objective sarcopenia detection.

    Ort, förlag, år, upplaga, sidor
    Oxford University Press, 2020
    Nyckelord
    Dual-energy x-ray absorptiometry, Imaging biomarkers, Magnetic resonance imaging, Muscle fat infiltration, Sarcopenic obesity
    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:liu:diva-169056 (URN)10.1093/gerona/glz229 (DOI)000579859200013 ()31642894 (PubMedID)2-s2.0-85086747036 (Scopus ID)
    Anmärkning

    Funding agencies: Medical Research CouncilMedical Research Council UK (MRC) [MC_PC_17228, MC_QA137853] Funding Source: Medline

    Tillgänglig från: 2020-09-07 Skapad: 2020-09-07 Senast uppdaterad: 2023-07-07Bibliografiskt granskad
    2. Adverse muscle composition is linked to poor functional performance and metabolic comorbidities in NAFLD
    Öppna denna publikation i ny flik eller fönster >>Adverse muscle composition is linked to poor functional performance and metabolic comorbidities in NAFLD
    2021 (Engelska)Ingår i: JHEP reports : innovation in hepatology, ISSN 2589-5559, Vol. 3, nr 1, artikel-id 100197Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Background & Aims: Sarcopenia and frailty are recognised as important factors in later stages of liver disease. However, theirrole in non-alcoholic fatty liver disease (NAFLD) is not yet fully understood. In this study we investigate the associations ofMRI-measured adverse muscle composition (AMC: low muscle volume and high muscle fat) with poor function, sarcopenia,and metabolic comorbidity within NAFLD in the large UK Biobank imaging study.

    Methods: A total of 9,545 participants were included. Liver fat, fat-tissue free muscle volume, and muscle fat infiltration werequantified using a rapid MRI protocol and automated image analysis (AMRA® Researcher). For each participant, a personalisedmuscle volume z-score (sex- and body size-specific) was calculated and combined with muscle fat infiltration for AMC detection. The following outcomes were investigated: functional performance (hand grip strength, walking pace, stairclimbing, falls) and metabolic comorbidities (coronary heart disease, type 2 diabetes). Sarcopenia was detected by combiningMRI thresholds for low muscle quantity and low hand grip strength according to the European working group definition.

    Results: The prevalence of sarcopenia in NAFLD (1.6%) was significantly lower (p <0.05) compared with controls without fattyliver (3.4%), whereas the prevalence of poor function and metabolic comorbidity was similar or higher. Of the 1,204 participants with NAFLD, 169 (14%) had AMC and showed 1.7–2.4× higher prevalence of poor function (all p <0.05) as well as 2.1×and 3.3× higher prevalence of type 2 diabetes and coronary heart disease (p <0.001), respectively, compared with thosewithout AMC.

    Conclusions: AMC is a prevalent and highly vulnerable NAFLD phenotype displaying poor function and high prevalence ofmetabolic comorbidity. Sarcopenia guidelines can be strengthened by including cut-offs for muscle fat, enabling AMCdetection.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2021
    Nyckelord
    AMC, adverse muscle composition; CHD, coronary heart disease; Cardiovascular disease; DXA, dual-energy x-ray absorptiometry; Diabetes mellitus; FFMV, fat-tissue free muscle volume; FIB-4, fibrosis-4; Fatty liver; HbA1c, glycated haemoglobin; MFI, muscle fat infiltration; Magnetic resonance imaging; Myosteatosis; NAFLD, non-alcoholic fatty liver disease; NASH, non-alcoholic steatohepatitis; Non-alcoholic steatohepatitis; PDFF, proton density fat fraction; Sarcopenia; Skeletal muscle; T2D, type 2 diabetes; VCG, virtual control group
    Nationell ämneskategori
    Gastroenterologi
    Identifikatorer
    urn:nbn:se:liu:diva-174426 (URN)10.1016/j.jhepr.2020.100197 (DOI)000648939900011 ()33598647 (PubMedID)2-s2.0-85099137898 (Scopus ID)
    Anmärkning

    Funding agency: Pfizer Inc.

    Tillgänglig från: 2021-03-21 Skapad: 2021-03-21 Senast uppdaterad: 2023-07-07Bibliografiskt granskad
    3. Adverse muscle composition predicts all-cause mortality in the UK Biobank imaging study
    Öppna denna publikation i ny flik eller fönster >>Adverse muscle composition predicts all-cause mortality in the UK Biobank imaging study
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    2021 (Engelska)Ingår i: Journal of Cachexia, Sarcopenia and Muscle, ISSN 2190-5991, E-ISSN 2190-6009, Vol. 12, nr 6, s. 1513-1526Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Background Adverse muscle composition (MC) as measured by magnetic resonance imaging has previously been linked to poor function, comorbidity, and increased hospitalization. The aim of this study was to investigate if adverse MC predicts all-cause mortality using data from UK Biobank. Methods There were 40 178 participants scanned using a 6 min magnetic resonance imaging protocol. Images were analysed for thigh fat-tissue free muscle volume and muscle fat infiltration (MFI) using AMRA (R) Researcher (AMRA Medical, Linkoping, Sweden). For each participant, a sex, weight, and height invariant muscle volume z-score was calculated. Participants were partitioned into four MC groups: (i) normal MC, (ii) only low muscle volume [&lt;25th percentile for muscle volume z-score (population wide)], (iii) only high MFI [&gt;75th percentile (population wide, sex-specific)], and (iv) adverse MC (low muscle volume z-score and high MFI). Association of MC groups with mortality was investigated using Cox proportional-hazard modelling with normal MC as referent (unadjusted and adjusted for low hand grip strength, sex, age, body mass index, previous diagnosis of disease (cancer, type 2 diabetes and coronary heart disease), lifestyle, and socioeconomic factors (smoking, alcohol consumption, physical activity, and Townsend deprivation index). Results Muscle composition measurements were complete for 39 804 participants [52% female, mean (SD) age 64.2 (7.6) years and body mass index 26.4 (4.4) kg/m(2)]. Three hundred twenty-eight deaths were recorded during a follow-up period of 2.9 (1.4) years after imaging. At imaging, adverse MC was detected in 10.5% of participants. The risk of death from any cause in adverse MC compared with normal MC was 3.71 (95% confidence interval 2.81-4.91, P &lt; 0.001). Only low muscle volume and only high MFI were independently associated with all-cause mortality [1.58 (1.13-2.21), P = 0.007, and 2.02 (1.51-2.71), P &lt; 0.001, respectively]. Adjustment of low hand grip strength [1.77 (1.28-2.44), P &lt; 0.001] did not attenuate the associations with any of the MC groups. In the fully adjusted model, adverse MC and only high MFI remained significant (P P = 0.020) while the association with only low muscle volume was attenuated to non-significance (P = 0.560). The predictive performance of adverse MC [1.96 (1.42-2.71), P &lt; 0.001] was comparable with that of previous cancer diagnosis [1.93 (1.47-2.53), P &lt; 0.001] and smoking [1.71 (1.02-2.84), P = 0.040]. Low hand grip strength was borderline non-significant [1.34 (0.96-1.88), P = 0.090]. Conclusions Adverse MC was a strong and independent predictor of all-cause mortality. Sarcopenia guidelines can be strengthened by including cut-offs for myosteatosis enabling detection of adverse MC.

    Ort, förlag, år, upplaga, sidor
    Wiley, 2021
    Nyckelord
    Sarcopenia; Magnetic resonance imaging; Frailty; Myosteatosis; Muscle fat infiltration
    Nationell ämneskategori
    Klinisk vetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-181070 (URN)10.1002/jcsm.12834 (DOI)000712391000001 ()34713982 (PubMedID)
    Anmärkning

    Funding Agencies|Pfizer Inc.Pfizer; European UnionEuropean Commission [847776]

    Tillgänglig från: 2021-11-18 Skapad: 2021-11-18 Senast uppdaterad: 2023-09-29
    4. Adverse muscle composition is a significant risk factor for all-cause mortality in NAFLD
    Öppna denna publikation i ny flik eller fönster >>Adverse muscle composition is a significant risk factor for all-cause mortality in NAFLD
    Visa övriga...
    2023 (Engelska)Ingår i: JHEP REPORTS, ISSN 2589-5559, Vol. 5, nr 3, artikel-id 100663Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Background & Aims: Adverse muscle composition (MC) (i.e., low muscle volume and high muscle fat) has previously been linked to poor functional performance and comorbidities in non-alcoholic fatty liver disease (NAFLD). In this study we aimed to investigate associations of all-cause mortality with liver fat, NAFLD, and MC in the UK Biobank imaging study.Methods: Magnetic resonance images of 40,174 participants were analyzed for liver proton density fat fraction (PDFF), thigh fat-free muscle volume (FFMV) z-score, and muscle fat infiltration (MFI) using the AMRA (R) Researcher. Participants with NAFLD were sex-, age-, and BMI-matched to participants without NAFLD with low alcohol consumption. Adverse MC was identified using previously published cut-offs. All-cause mortality was investigated using Cox regression. Models within NAFLD were crude and subsequently adjusted for sex, age, BMI (M1), hand grip strength, physical activity, smoking, alcohol (M2), and previous cancer, coronary heart disease, type 2 diabetes (M3).Results: A total of 5,069 participants had NAFLD. During a mean (+/- SD) follow-up of 3.9 (+/- 1.4) years, 150 out of the 10,138 participants (53% men, age 64.4 [+/- 7.6] years, BMI 29.7 [+/- 4.4] kg/m2) died. In the matched dataset, neither NAFLD nor liver PDFF were associated with all-cause mortality, while all MC variables achieved significance. Within NAFLD, adverse MC, MFI and FFMV z-score were significantly associated with all-cause mortality and remained so in M1 and M2 (crude hazard ratios [HRs] 2.84, 95% CI 1.70-4.75, p &lt;0.001; 1.15, 95% CI 1.07-1.24, p &lt;0.001; 0.70, 95% CI 0.55-0.88, p &lt;0.001). In M3, the rela-tionship was attenuated for adverse MC and FFMV z-score (adjusted HRs 1.72, 95% CI 1.00-2.98, p = 0.051; 0.77, 95% CI 0.58-1.02, p = 0.069) but remained significant for MFI (adjusted HR 1.13, 95% CI 1.01-1.26, p = 0.026).Conclusions: Neither NAFLD nor liver PDFF was predictive of all-cause mortality. Adverse MC was a strong predictor of all -cause mortality in individuals with NAFLD.Impact and implications: Individuals with fatty liver disease and poor muscle health more often suffer from poor functional performance and comorbidities. This study shows that they are also at a higher risk of dying. The study results indicate that measuring muscle health (the patients muscle volume and how much fat they have in their muscles) could help in the early detection of high-risk patients and enable targeted preventative care.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

    Ort, förlag, år, upplaga, sidor
    ELSEVIER, 2023
    Nyckelord
    sarcopenia; Magnetic resonance imaging; Imaging biomarker; survival; Muscle fat infiltration; Myosteatosis; UK Biobank
    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:liu:diva-194831 (URN)10.1016/j.jhepr.2022.100663 (DOI)000990053500001 ()36818816 (PubMedID)
    Tillgänglig från: 2023-06-14 Skapad: 2023-06-14 Senast uppdaterad: 2023-10-30
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  • 7.
    Martínez, Victoria Van Orden
    Linköpings universitet, Institutionen för kultur och samhälle, Avdelningen för kultur, samhälle, form och medier. Linköpings universitet, Institutionen för kultur och samhälle, Avdelningen för historia, konstvetenskap och religionsvetenskap. Linköpings universitet, Filosofiska fakulteten.
    Afterlives: Jewish and Non-Jewish Polish Survivors of Nazi Persecution in Sweden Documenting Nazi Atrocities, 1945-19462023Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [sv]

    I denna avhandling undersöks judiska och icke-judiska polacker som överlevde den nazistiska förföljelsen och kom till Sverige 1945 som så kallade repatriander och som hade kopplingar till det Polska källinstitutet i Lund. Undersökningen fokuserar på hur de engagerade sig i transnationella sociala och politiska processer under tiden direkt efter kriget, bland annat hur de dokumenterade den nazistiska förföljelsen och bidrog till humanitärt och rättskipande arbete efter kriget. Det Polska källinstitutet var ett transnationellt initiativ, som dokumenterade polska överlevandes upplevelser av den nazistiska förföljelsen för historieskrivnings- och rättskipningsändamål under 1945 och 1946. Det är ett av få sådana initiativ som togs av överlevande som var flyktingar i ett land som inte var direkt inblandat i andra världskriget och som dokumenterade såväl judiska som icke-judiska överlevande och deras erfarenheter. I denna monografi undersöks på vilka särskilda sätt överlevande deltog i sociala och politiska processer under efterkrigstiden, samt vilken inverkan de överlevandes sårbarhet, agens och olika former av strukturellt stöd hade på deras arbete och insatser. Vidare undersöks hur könstillhörighet och andra skillnader påverkade de överlevandes agerande och hur dessa fortsätter att påverka de diskursiva och historiografiska tolkningarna och förklaringarna av agerandet. Resultaten visar hur de polska överlevandena kopplade till det Polska källinstitutet, trots att de levde under olika överlappande former av osäkerhet och sårbarhet, upprätthöll sin tidigare aktivism och sina motstånds- och stödnätverk. De använde sina kunskaper, etiska värderingar och praktiska strategier för att förbättra sina villkor och arbeta för rättvisa. På så sätt bidrar avhandlingen till nya insikter som börjar fylla i forskningsluckorna i den befintliga svenska och internationella forskningen om andra världskriget och Förintelsen, historiska kommissioner och dokumentationscenter för överlevande, fördrivna personer under efterkrigstiden, relationer mellan judiska och icke-judiska polacker, migranters kunskap samt humanitärt och rättskipande arbete efter kriget.

  • 8.
    Alarcón, Alvaro
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    All-Fiber System for Photonic States Carrying Orbital Angular Momentum: A Platform for Classical and Quantum Information Processing2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Skydd av konfidentiell information är ett grundläggande behov i det samhälle vi lever i. Denna uppgift blir mer relevant när man observerar att datatrafiken ökar exponentiellt varje dag, liksom antalet attacker på telekommunikationsinfrastrukturen. Från naturvetenskapen har det starkt hävdats att kvantkommunikation har en stor potential att lösa detta problem, i en sådan utsträckning att olika statliga och industriella enheter tror att skyddet som tillhandahålls av kvantkommunikation kommer att vara en viktig del av informationssäkerhet de kommande decennierna.

    Att implementera kvantteknik både i nuvarande optiska nätverk och i industriella system är dock inte en trivial uppgift, med tanke på att en stor del av nuvarande kvantoptiska system inte är i optiska fiber, vilket kan bli en begränsning. Genom hela denna avhandling presenterar vi en plattform som är helt konstruerad med optiska fiber som tillåter ett brett utbud av uppgifter som syftar till att ta ett steg framåt när det gäller integration med nu-varande optiska nätverk. Bland huvuddragen i denna idé utmärker den skapandet och detekteringen av fotoniska kvanttillstånd i  ”Orbital Angular Momentum”, såväl som allmänna överlagringar  av rumsliga optiska moder som kan transmitteras inom en optisk fiber. Plattformen kan också konfigureras för generering av slumptal från kvantmekaniska mätningar, vilket är en central aspekt i framtida hantering av information.  

    Vår plattform är baserad på användningen av nya tekniker för ”Space Division Multiplexing” (på Engelska) såsom ”few-mode-fibers” och ”photonic lanterns”. Dessutom kan vår plattform skalas till högre dimensioner, den fungerar i 1550 nm (telekommunikationsbandet) och alla komponenter som används för dess implementering är kommersiellt tillgängliga, därför kan resultaten som presenteras i denna avhandling vara ett robust alternativ för att säkerställa kompatibiliteten av nya framväxande teknologier och experiment med nästa generations optiska nätverk och öppnar nya möjligheter för kvantkommunikation.   

    Delarbeten
    1. Few-Mode-Fiber Technology Fine-tunes Losses in Quantum Communication Systems
    Öppna denna publikation i ny flik eller fönster >>Few-Mode-Fiber Technology Fine-tunes Losses in Quantum Communication Systems
    2021 (Engelska)Ingår i: Physical Review Applied, E-ISSN 2331-7019, Vol. 16, nr 3, artikel-id 034018Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A natural choice for quantum communication is to use the relative phase between two paths of a single photon for information encoding. This method was nevertheless quickly identified as impractical over long distances, and thus a modification based on single-photon time bins has become widely adopted. It, how-ever, introduces a fundamental loss, which increases with the dimension and limits its application over long distances. Here solve this long-standing hurdle by using a few-mode-fiber space-division-multiplexing platform working with orbital-angular-momentum modes. In our scheme, we maintain the practicability provided by the time-bin scheme, while the quantum states are transmitted through a few-mode fiber in a configuration that does not introduce postselection losses. We experimentally demonstrate our proposal by successfully transmitting phase-encoded single-photon states for quantum cryptography over 500 m of few-mode fiber, showing the feasibility of our scheme.

    Ort, förlag, år, upplaga, sidor
    AMER PHYSICAL SOC, 2021
    Nationell ämneskategori
    Annan fysik
    Identifikatorer
    urn:nbn:se:liu:diva-179872 (URN)10.1103/PhysRevApplied.16.034018 (DOI)000698660300003 ()
    Anmärkning

    Funding Agencies|Ceniit Linkoping University; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2017-04470]; QuantERA SECRET [2019-00392]; Knut and Alice Wallenberg Foundation through the Wallenberg Center for Quantum Technology; Fondo Nacional de Desarrollo Cientifico y TecnologicoComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [1200859]; ANID Millennium Science Initiative program [ICN17_012]

    Tillgänglig från: 2021-10-06 Skapad: 2021-10-06 Senast uppdaterad: 2023-09-14
    2. Dynamic generation of photonic spatial quantum states with an all-fiber platform
    Öppna denna publikation i ny flik eller fönster >>Dynamic generation of photonic spatial quantum states with an all-fiber platform
    2023 (Engelska)Ingår i: Optics Express, E-ISSN 1094-4087, Vol. 31, nr 6, s. 10673-10683Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Photonic spatial quantum states are a subject of great interest for applications in quantum communication. One important challenge has been how to dynamically generate these states using only fiber-optical components. Here we propose and experimentally demonstrate an all-fiber system that can dynamically switch between any general transverse spatial qubit state based on linearly polarized modes. Our platform is based on a fast optical switch based on a Sagnac interferometer combined with a photonic lantern and few-mode optical fibers. We show switching times between spatial modes on the order of 5 ns and demonstrate the applicability of our scheme for quantum technologies by demonstrating a measurement-device-independent (MDI) quantum random number generator based on our platform. We run the generator continuously over 15 hours, acquiring over 13.46 Gbits of random numbers, of which we ensure that at least 60.52% are private, following the MDI protocol. Our results show the use of photonic lanterns to dynamically create spatial modes using only fiber components, which due to their robustness and integration capabilities, have important consequences for photonic classical and quantum information processing.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

    Ort, förlag, år, upplaga, sidor
    Optica Publishing Group, 2023
    Nationell ämneskategori
    Annan fysik
    Identifikatorer
    urn:nbn:se:liu:diva-193996 (URN)10.1364/OE.481974 (DOI)000974423800007 ()37157609 (PubMedID)
    Anmärkning

    Funding Agencies|Knut och Alice Wallenbergs Stiftelse; QuantERA grant SECRET [VR 2019-268 00392]; Swedish Research 266 Council [VR 2017-04470]; Centrum foer Industriell Informationsteknologi, Linkoepings Universitet

    Tillgänglig från: 2023-05-23 Skapad: 2023-05-23 Senast uppdaterad: 2023-11-13
    3. A few-mode fiber Mach-Zehnder interferometer for quantum communication applications
    Öppna denna publikation i ny flik eller fönster >>A few-mode fiber Mach-Zehnder interferometer for quantum communication applications
    2020 (Engelska)Ingår i: Frontiers in Optics / Laser Science / [ed] B. Lee, C. Mazzali, K. Corwin, and R. Jason Jones, Optical Society of America, 2020, artikel-id LM1F.6Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

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

    Ort, förlag, år, upplaga, sidor
    Optical Society of America, 2020
    Serie
    OSA Technical Digest
    Nyckelord
    Few mode fibers, Quantum communications, Quantum key distribution, Single mode fibers, Space division multiplexing, Step index fibers
    Nationell ämneskategori
    Atom- och molekylfysik och optik Kommunikationssystem
    Identifikatorer
    urn:nbn:se:liu:diva-184461 (URN)10.1364/LS.2020.LM1F.6 (DOI)9781943580804 (ISBN)
    Konferens
    Laser Science 2020, Washington, DC, United States, 14–17 September 2020
    Anmärkning

    Funding: The authors acknowledge support from Ceniit Linköping University, the Swedish Research Council (VR 2017-04470), the Knut and Alice Wallenberg Foundation through the Wallenberg Center for Quantum Technology (WACQT) and by the QuantERA grant SECRET (VR grant no. 2019-00392).

    Tillgänglig från: 2022-04-22 Skapad: 2022-04-22 Senast uppdaterad: 2023-09-14Bibliografiskt granskad
    4. Creating Spatial States of Light for Quantum Information with Photonic Lanterns
    Öppna denna publikation i ny flik eller fönster >>Creating Spatial States of Light for Quantum Information with Photonic Lanterns
    2021 (Engelska)Ingår i: Applied Industrial Optics 2021 / [ed] G. Miller, A. Smith, I. Capraro, and J. Majors, Optical Society of America, 2021, artikel-id W2A.2Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

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

    Ort, förlag, år, upplaga, sidor
    Optical Society of America, 2021
    Serie
    OSA Technical Digest
    Nyckelord
    Few mode fibers, Quantum communications, Quantum cryptography, Quantum information, Space division multiplexing, Spatial light modulators
    Nationell ämneskategori
    Atom- och molekylfysik och optik
    Identifikatorer
    urn:nbn:se:liu:diva-184462 (URN)10.1364/AIO.2021.W2A.2 (DOI)9781943580934 (ISBN)
    Konferens
    Applied Industrial Optics: Spectroscopy, Imaging and Metrology 2021, Washington, DC, United States, 26–28 July 2021
    Tillgänglig från: 2022-04-22 Skapad: 2022-04-22 Senast uppdaterad: 2023-09-14Bibliografiskt granskad
    5. Quantum Random Number Generation Based on Spatial Modal Superposition over Few-Mode-Fibers
    Öppna denna publikation i ny flik eller fönster >>Quantum Random Number Generation Based on Spatial Modal Superposition over Few-Mode-Fibers
    2022 (Engelska)Ingår i: Frontiers in Optics + Laser Science 2022 (FIO, LS), Optica Publishing Group , 2022Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

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

    Ort, förlag, år, upplaga, sidor
    Optica Publishing Group, 2022
    Serie
    Frontiers in Optics + Laser Science 2022 (FIO, LS)
    Nyckelord
    Few mode fibers, Optical fibers, Random number generation, Single mode fibers, Single photon detectors, Variable optical attenuators
    Nationell ämneskategori
    Atom- och molekylfysik och optik
    Identifikatorer
    urn:nbn:se:liu:diva-197797 (URN)10.1364/FIO.2022.JTu5A.28 (DOI)978-1-957171-17-3 (ISBN)
    Konferens
    Frontiers in Optics + Laser Science 2022 (FIO, LS), Technical Digest Series, Rochester, New York
    Tillgänglig från: 2023-09-14 Skapad: 2023-09-14 Senast uppdaterad: 2023-09-14Bibliografiskt granskad
  • 9. Beställ onlineKöp publikationen >>
    Leijon, Freddy
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Aluminium alloy development for Additive Manufacturing2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Powder Bed Fusion (PBF Additive Manufacturing AM have emerged as a promising manufacturing process possessing a powerful combination of characteristics. Most noticeable are the near-net-shape, short lead time and flexibility, both with regard in design freedom and in part-to-part variation. Aluminium alloys are used in everything from food packaging, furniture's, to cars and airplanes. To accommodate for this wide range in material requirements, different alloys have been developed over the past century. To reach the full potential of AM, a thoroughly work lies ahead of the research community to find, tailor and refine alloys.

    This work has focused on experimentally screening of AM alloys, for their printability and potential properties. To accelerate this, a novel high through put method was first developed to efficiently produce a broad range of alloys both with respect to compositions and alloying elements. This method consists of two steps; in the first step a compositional alloy gradient film is deposited on an aluminium substrate, and in a second step a microstructure mimicking PBF is formed by either laser or electron beam melting of the film. Gradients up to 500mm in length ranging from 0-85wt% in alloying content were achieved. This enabled high resolution studies of the influence of alloying elements over wide compositional intervals. Various aspects of the material were possible to investigate such as: Grain size, hardness, printability, evaporation losses, solid solution, electrical conductivity and microstructure. The results were verified against the available literature, and a strong correlation between properties of the PBF mimicked materials and actual PBF materials were confirmed.

    With the developed screening method, printability i.e. the material's capacity to be processed in PBF without formation of cracks , could be studied and mapped out for a large set of alloys. The AlMgSi system were found to be printable without grain refinement if Si+Mg<0.7wt% or Si+2/3Mg>4wt% for Mg < 3wt% and Si > 3wt%. Investigations of Til-xMxB2 and Al3Til-xMx grain refiners in 2wt% Cu alloys reveled that grain refinement and printability strongly correlated to both x and the element M(Zr,Ta,V,W). However, no clear relationship between the grain size and the lattice parameters of Til-xMxB2 and Al3Til-xMx were found.

    In addition to mapping out printability, hardness as a function of composition was also mapped out for the binary alloys Al -Ti, -Zr, -Nb, -Sr and the AlMgSi system. Other important findings are that the Mg loss due to evaporation and the solid solution of Mg was found to depend linearly on the amount of Mg, and a transition from equiaxed to fine lamellar Al4Sr intermetallic going above 5wt%. Altogether, the screening method developed in this work offer a unique way to efficiently study composition dependent transitions in printability, microstructure and other material properties which are otherwise difficult to foresee or experimentally laborious to study.

    Delarbeten
    1. A novel rapid alloy development method towards powder bed additive manufacturing, demonstrated for binary Al-Ti, -Zr and -Nb alloys
    Öppna denna publikation i ny flik eller fönster >>A novel rapid alloy development method towards powder bed additive manufacturing, demonstrated for binary Al-Ti, -Zr and -Nb alloys
    Visa övriga...
    2021 (Engelska)Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 211, artikel-id 110129Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Powder bed fusion (PBF) methods offer the best material properties among metal additive manufacturing (AM) processes. Yet, alloy development for PBF is only at its infancy and has a great untapped potential. This originates from the high solidification rate within the melt pool and to exploit the full potential of materials produced by PBF methods, a diligent work lies ahead. This paper presents a high-throughput method to rapidly screen large compositional alloy intervals experimentally for their PBF feasibility, which can drastically reduce the time needed for alloy development and provide valuable data for modelling. Our method consists of two steps; co-sputtering and electron beam re-melting. First step produces an alloy gradient film on a sheet substrate. The film is then re-molted to produce a PBF mimicked microstructure. The method is successfully demonstrated on binary systems; Al-Ti,-Zr and-Nb and produced gradients in compositional ranges of 3-50 wt%Ti, 1-15 wt%Zr and 2-15 wt%Nb over a length of 200 mm. From the produced materials, the alloying efficiency could be investigated and determined regarding hardness and grain refinement. Zr shows the highest strength contribution per at% and the best grain refinement at low levels. However, at higher levels grain refinement efficiency decreases for Zr. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

    Ort, förlag, år, upplaga, sidor
    Elsevier Science Ltd, 2021
    Nyckelord
    High through put method; Aluminium alloys; Powder bed fusion; Additive manufacturing; Electron Beam
    Nationell ämneskategori
    Metallurgi och metalliska material
    Identifikatorer
    urn:nbn:se:liu:diva-180511 (URN)10.1016/j.matdes.2021.110129 (DOI)000706882800002 ()
    Anmärkning

    Funding Agencies|Norsk Hydro ASA; Carl Tryggers Foundation for Scientific Research [CTS 15:219, CTS 14:431]

    Tillgänglig från: 2021-10-25 Skapad: 2021-10-25 Senast uppdaterad: 2023-04-18
    2. Investigation of Ti-1_x(Zr,Ta,V,W)(x)B-2 and A(l3)Ti(1_x)(Zr,V)(x) grain refiners in additively manufactured Al-2 wt%Cu alloys by a high throughput method
    Öppna denna publikation i ny flik eller fönster >>Investigation of Ti-1_x(Zr,Ta,V,W)(x)B-2 and A(l3)Ti(1_x)(Zr,V)(x) grain refiners in additively manufactured Al-2 wt%Cu alloys by a high throughput method
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    2022 (Engelska)Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 222, artikel-id 111093Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Grain refinement plays a central role in powder bed fusion (PBF) additive manufacturing by preventing hot cracking and thus enabling the development of high-strength alloys. However, the mechanism behind grain refinement is not fully understood for conventional casting, nor for PBF. In this work, a high throughput method have been used to produce Al-2 wt%Cu alloys with additions of Ti1-xM(Zr,Ta,V,W)(x)B-2, Al3Ti1-xM(Zr,V)(x) or AlB2 grain refiners for 0.1 &lt; x &lt; 0.9. It was found that grain size varied with x, M and the sum of Ti + M. Ti1-xMxB2 grain refiners offered no advantage over Al3Ti1-xMx. Overall, Ti and Zr provide the best grain refinement, both as Ti1-xMxB2 and Al3Ti1-xMx. However, Ti1-xZrxB2 had a grain refinement minimum around x = 0.65-0.70. The behavior was similar with Ta, but to a lesser extent. V and W had detrimental effects on grain refinement. Despite the fact that no AlB2 particles were observed, additions of B provided excellent grain refinement and was more efficient than Ti below 0.5at%. Ti1-xMxB2 lattice parameters varied with x and followed Vegards law, however, a clear relationship between grain size and epitaxial strain/lattice match could not be established. Similarly, the growth restricting factor alone was not a predictor of grain size.

    Ort, förlag, år, upplaga, sidor
    Elsevier Science Ltd, 2022
    Nationell ämneskategori
    Metallurgi och metalliska material
    Identifikatorer
    urn:nbn:se:liu:diva-188764 (URN)10.1016/j.matdes.2022.111093 (DOI)000855347300002 ()
    Anmärkning

    Funding Agencies|Norsk Hydro ASA; Centre in Nanoscience and Technology at LiTH. Carl Tryggers Foundation for Scientific Research [CTS 14:431]; AMEXCI AB; [CTS 15:219]

    Tillgänglig från: 2022-09-26 Skapad: 2022-09-26 Senast uppdaterad: 2023-04-18
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    Umunoza Gasana, Emelyne
    Linköpings universitet, Matematiska institutionen, Tillämpad matematik. Linköpings universitet, Tekniska fakulteten.