| 1. |
- Bengtsson, Olof, 1969-
(author)
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Design and Characterization of RF-Power LDMOS Transistors
- 2008
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Doctoral thesis (other academic/artistic)abstract
- In mobile communication new applications like wireless internet and mobile video have increased the demand of data-rates. Therefore, new more wideband systems are being implemented. Power amplifiers in the base-stations that simultaneously handle these wideband signals for many terminals (handhelds) need to be highly linear with a considerable band-width. In the past decade LDMOS has been the dominating technology for use in these RF-power amplifiers. In this work LDMOS transistors possible to fabricate in a normal CMOS process have been optimized and analyzed for RF-power applications. Their non-linear behavior has been explored using load-pull measurements. The mechanisms of the non-linear input capacitance have been analyzed using 2D TCAD simulations. The investigation shows that the input capacitance is a large contributor to phase distortion in the transistor. Computational load-pull TCAD methods have been developed for analysis of RF-power devices in high-efficiency operation. Methods have been developed for class-F with harmonic loading and for bias-modulation. Load-pull measurements with drain-bias modulation in a novel measurement setup have also been conducted. The investigation shows that the combination of computational load-pull of physical transistor structures and direct measurement evaluation with modified load-pull is a viable alternative for future design of RF-power devices. Simulations and measurements on the designed LDMOS shows a 10 to 15 % increase in drain efficiency in mid-power range both in simulations and measurements. The computational load-pull method has also been used to investigate the power capability of LDMOS transistors on SOI. This study indicates that either a low-resistivity or high-resistivity substrate should be used in manufacturing of RF-power LDMOS transistors on SOI to achieve optimum efficiency. Based on a proper substrate selection these devices exhibit a 10 % higher drain-efficiency mainly due to lower dissipated power in the devices.
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| 2. |
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| 3. |
- Berman, Anne H, et al.
(author)
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Teaching digital mental health treatment in theory and practice : a proof-of-concept pilot and feasibility study
- 2023
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In: International Journal of Behavioral Medicine. ; , s. 66-66, s. 6-7
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Conference paper (peer-reviewed)abstract
- Objective: The labor market for mental health professionals increasingly requires competency in digital mental health treatment (DMHT). This presentation targets DMHT practitioners as course developers and teachers, describing proof-of-concept findings based on a) development of a remotely delivered DMHT course; and b) results from a qualitative evaluation of students’ experiences from the first course round.Methods: The course syllabus was developed through two structured workshops, attended by 11 stakeholders with DMHT experience. For the qualitative evaluation, interviews with seven women participants in the first course round were analyzed according to an inductive, phenomenographic approach.Results: The course development process established a 12-week syllabus covering historical development and evidence for DMHT and an 8-week DMHT clinical practicum treating students with common mental health problems. Examination was formulated as individual case reports encompassing reflections on a) the therapist and client roles; b) ethical aspects of DMHT; and c) future innovations for DMHT. The course is offered via a standard learning management system, with the practicum completed on a separate DMHT platform. The qualitative analysis of the first pilot course round, where students role-played therapists and clients, yielded six themes: overall course experience, treatment program and platform, therapist role, client role, supervision and the alliance.Conclusions: This proof-of-concept procedure led to course establishment in two formats: as an ordinary elective course for advanced clinical psychology students, and as a stand-alone national course for health professionals with basic psychotherapy training. Following local adaptation, the course could be replicated at additional universities globally.
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| 4. |
- Berman, Anne H., et al.
(author)
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Teaching digital mental health treatment in theory and practice : A proof-of-concept pilot and feasibility study
- 2023
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In: International Journal of Behavioral Medicine. - : Springer. - 1070-5503 .- 1532-7558. ; 30, s. S67-S67
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Journal article (other academic/artistic)abstract
- Background: Improving relationship dynamics positively impacts both partners’ health among couples. However, few studies have investigated sexual and gender minority (SGM) couples’ relationship goals and their experiences toward achieving them.Purpose: The present study investigated SGM couples’ experiences that centered on them working toward or maintaining their relationship goals over time.Method: From a cohort study with SGM couples, a purposive sample of 40 couples was selected and interviewed over Zoom. Interviews were individual-level, semi-structured, and recorded. Thematic analysis was used to analyze the transcripts.Results: Approximately half of the 40 couples identified as gay male couples, a third as lesbian couples, and about one-fifth as queer or gender minority couples. Top three reported relationship goals were 1) improving communication, 2) working on finances, and 3) enhancing intimacy. Feeling emotionally connected, career-related decisions, and improving sexual satisfaction were other commonly reported goals. Overall, most partners felt they made progress toward at least 1 of their 3 relationship goals within the prior 6 months. However, perceived relationship goal progress varied extensively between partners across couple groups. Facilitator-related themes about relationship goal progress included dyadic efforts, having a support system including professional help, and planning. Barrier-related themes included nonexistent or minimal effort, different communication styles, employment and economical struggles, and competing life and health priorities.Conclusion(s): Dyadic efforts and support systems were key toward someone working toward or maintaining their relationships goals. Findings suggest key relationship functioning areas to target in a future multiple health behavior change intervention for SGM couples.
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| 5. |
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| 6. |
- Karlsson, Camilla A-C, et al.
(author)
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Detergent Induced Removal of b-Lactoglobulin from Stainless Steel Surfaces at Influenced by Surface Pretreatment
- 1999
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In: Journal of Colloid and Interface Science. - : Elsevier BV. - 1095-7103 .- 0021-9797. ; 220, s. 471-473
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Journal article (peer-reviewed)abstract
- The adsorption of β-lactoglobulin to stainless steel and its subsequent removal were followed using in situ null ellipsometry. The influence of the surface pretreatment on the protein removal by the surfactant SDS and by sodium hydroxide was studied. All surfaces were precleaned in strongly alkaline solution. Some surfaces received no further pretreatment, while others were either passivated in nitric acid or plasma-cleaned prior to experiments. Stainless steel surfaces subjected to different surface pretreatments showed considerable differences in cleaning behavior. Cleaning, using NaOH, of surfaces which had been precleaned with alkali only or with plasma resulted in practically complete β-lactoglobulin removal. In contrast, appreciable amounts of protein remained on passivated stainless steel. Protein removal by SDS was limited and comparable for all three surface pretreatments investigated. Only minor effects on the protein adsorption tendency were observed. The amounts of β-lactoglobulin adsorbed tended to be somewhat lower on the passivated surfaces.
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| 7. |
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| 8. |
- Olsson, Claes-Olof A., et al.
(author)
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Early Precipitation Stages of Sigma Phase in Alloy 28 Studied with Scanning Electron Microscopy and Atom Probe Tomography
- 2021
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In: ISIJ International. - 0915-1559. ; 61:3, s. 881-887
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Journal article (peer-reviewed)abstract
- This study deals with early stages of sigma phase growth in a high end austenitic stainless steel - Alloy 28 (EN 1.4563/UNS N08028). Its precipitation kinetics was followed by a series of heat treatments at 800 degrees C for holding times up to 30 000 s. The samples were studied with high resolution scanning electron microscopy and atom probe tomography. Detailed image analysis of the micrographs made it possible to quantify the growth rate of the precipitates. It was shown that diffusion limited growth along grain boundaries was about 15 times faster than growth perpendicular to a grain face. By combining the image data with quantitative chemical analysis of the phase boundaries, it was possible to estimate diffusion coefficients in the lattice and in the grain boundaries; grain boundary diffusion coefficients were about 250 times those of the lattice.
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| 9. |
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| 10. |
- Smeets, Stef, et al.
(author)
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Quantitative Phase Analysis for Carbide Characterization in Steel Using Automated Electron Diffraction
- 2019
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In: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X. ; 90:1
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Journal article (peer-reviewed)abstract
- Carbides are critical to many different properties in a steel. In this paper, the quantification of a carbide powder extracted from a stainless steel analyzed with profile refinement of X-ray powder diffraction patterns, is compared to a novel technique for automated electron diffraction pattern collection with a transmission electron microscope. The automated analysis has the advantage of collecting patterns from individual particles, hence avoiding issues such as overlapping reflections in powder diffractograms. Electron diffraction patterns with satisfactory quality are selected through a deep convoluted neural network and matched to a library of pre-calculated diffraction patterns, corresponding to a set of selected carbide crystal structures. The quantitative results from the automated particle analysis are in good agreement with the phases identified by powder profile refinement.
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| 11. |
- Westin, Elin M., et al.
(author)
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Weld oxide formation on lean duplex stainless steel
- 2008
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In: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 50:9, s. 2620-2634
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Journal article (peer-reviewed)abstract
- Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition.
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| 12. |
- Öhrwall Rönnbäck, Anna, 1969-, et al.
(author)
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Collaborative Development of Public Information Systems : A Case Study of “Sambruk” e-Services Development
- 2010
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In: eChallenges e-2010 Conference Proceedings. - : IEEE Press. - 9781905824205 ; , s. 1-7
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Conference paper (peer-reviewed)abstract
- Today, public e-services provide essential and efficient tools for municipalities to serve their citizens. However, the development can be quite complex, and in order to efficiently develop solutions, municipalities need to collaborate with many actors and stakeholders such as IT-vendors and developers, as well as government agencies. In this paper collaboration with various stakeholders in different scenarios, comprising four different information systems development projects are analysed, and the pro’s and con’s in the various approaches are described. Furthermore, there are important lessons learned and identified in the three alternatives of user involvement in the projects covered in the paper. Sambruk, ie the Swedish Association of Municipalities for Joint Development of eServices, has in several projects challenged the existing near monopolistic market and business models in Sweden by carrying out significant development projects, utilising new approaches in user involvement and setting up a new collaborative arena for Swedish municipalities, working together in creating new e-service solutions.
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| 13. |
- Öhrwall Rönnbäck, Anna, et al.
(author)
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Innovative Business Models Enhancing Open Source Software in the Public Sector
- 2010
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In: e-Challenges.
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Conference paper (peer-reviewed)abstract
- The objective of this paper is to suggest new business models and supporting arrangements for open source software in the public sector, specifically for municipalities. Methodologically, the study was carried out as a practical inquiry. Results from the initial diagnosis of longitudinal case studies 2005-2008 in a Swedish network of 80 collaborating municipalities, and a survey 2008 to all Swedish national and local authorities, indicated that Swedish municipalities do not use OSS to a large extent for several reasons, and that experience sharing and a supporting framework were requested. As a solution, a semi-open business model framework was suggested. This framework was developed and implemented in the form of action research. Evaluation of the implementation indicated two major conclusions presented in this paper. First, it that a semi-open source business model could strengthen the community, in so motto that the user-driven innovative solutions stay under control of the user organization. This prevents that the customer’s own development efforts in collaborative projects unintentionally are transferred to supplier companies, and need to be re-purchased in the form of packaged solutions, a phenomena that was observed in several previously studied cases. Second, it was concluded that the semi-open source business model can work only if both customer-side and supplier-side can take advantage. An open attitude to enhance fulfilment of the supplier’s drivers, such as commercialization opportunities, is needed from the customer side. Otherwise important knowledge contributions from suppliers may be limited.
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