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- Ghandi, Reza, et al.
(författare)
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Experimental evaluation of different passivation layers on the performance of 3kV 4H-SiC BJTs
- 2010
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 645-648:Part 1-2, s. 661-664
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the electrical performance in terms of maximum current gain, ON-resistance and blocking capability has been compared for 4H-SiC BJTs passivated with different surface passivation layers. Variation in BJT performance has been correlated to densities of interface traps and fixed oxide charge, as evaluated through MOS capacitors. Six different methods were used to fabricate SiO2 surface passivation on BJT samples from the same wafer. The highest current gain was obtained for PECVD deposited SiO2 which was annealed in N2O ambient at 1100 degrees C during 3 hours. Variations in breakdown voltage for different surface passivations were also found, and this is attributed to differences in fixed oxide charge that can affect the optimum dose of the high voltage JTE termination.
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- Ückert, S., et al.
(författare)
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Expression and distribution of key proteins of the endocannabinoid system in the human seminal vesicles
- 2018
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Ingår i: Andrologia. - : Hindawi Limited. - 0303-4569. ; 50:2
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Tidskriftsartikel (refereegranskat)abstract
- The endocannabinoid system (ECS), comprising the cannabinoid receptors (CBR), their ligands, and enzymes controlling the turnover of endocannabinoids, has been suggested to be involved in male reproductive function. As information is scarce on the expression of the ECS in human male reproductive tissues, this study aimed to investigate by means of molecular biology (RT-PCR) and immunohistochemistry/immunofluorescence the expression and distribution of CB1 and CB2, GPR55 (an orphan G protein-coupled receptor that recognises cannabinoid ligands) and FAAH (isoforms 1 and 2) in the human seminal vesicles (SV). The specimens expressed PCR products corresponding to CB1 (66 bp), CB2 (141 bp), GPR55 (112 bp), FAAH1 (260 bp) and FAAH2 (387 bp). Immumohistochemistry revealed dense expression of CB1, CB2 and GPR55 located to the pseudo-stratified columnar epithelium and varicose nerves (also characterised by the expression of vasoactive intestinal polypeptide and calcitonin gene-related peptide). Cytosolic staining for FAAH1 and FAAH2 was seen in cuboidal cells of all layers of the epithelium. No immunoreactivity was detected in the smooth musculature or nerve fibres. CB1, CB2, GPR55, FAAH1 and FAAH2 are highly expressed in the human SV. Considering their localisation, the ECS may be involved in epithelial homeostasis, secretory function or autonomic mechano-afferent signalling.
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- Cavicchi, A., et al.
(författare)
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INFORMEG, a new evaluation system for family medicine trainees : Feasibility in an Italian rural setting
- 2016
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Ingår i: Rural and Remote Health. - 1445-6354. ; 16:3
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In Italy the course to become a general practitioner (GP) lasts 3 years and includes both theoretical and practical study. Different from the theoretical part, until recently the practical activity has not been assessed at all. The Emilia Romagna Regional Health Authority has developed a special program called INFORMEG (Management of Tutoring during the Triennial Specific Training in General Practice), aimed at assessing primary doctor trainees' practical skills. INFORMEG includes a list of predefined cases of specific diseases, conditions or health problem, a web application and a smartphone app, aimed at assisting trainee self-management and helping the tutor in the assessment of trainee performance. The Emilia Romagna Regional Health Authority divided the pre-defined cases into three categories (A, B and C) according to their relevance to a trainee's education and coded them using the International Classification of Primary Care (ICPC). The aim of this project report is to illustrate the implementation of INFORMEG in a rural setting. Methods: Program evaluation took place from 2 May to 31 October 2013 during GPs' routine clinical activities. The following steps were accomplished during every meeting: (1) consultation recording; (2) identification of the reason for the encounter (RfE); (3) classification of the diagnostic procedure(s) performed (diagnostic/therapeutic/test results/administrative/advice); (4) classification of special procedures called 'practical clinical skills' and (5) elaboration of the final diagnosis after the encounter. Results: The number of cases of specific disease or condition encountered by the trainee were 98 for type A, 57 for type B and 22 for type C. A total of 605 RfEs were collected: 376 for type A cases, 147 for type B cases and 82 for type C cases. A total of 976 procedures were performed during the 6 months: 590 procedures for the type A cases, 271 for type B and 115 for type C. Conclusions: The pre-selected health problems were almost all addressed, thus confirming the good degree of representativeness of these clinical cases even in a rural setting. The ICPC coding helped the trainee in the construction of the case according to the logical process of family medicine. Two things to amend in INFORMEG are the absence of common arrhythmic conditions such as atrial fibrillation and the absence of means to assess the patient-trainee relationship.
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- Ghandi, Reza, et al.
(författare)
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Surface-passivation effects on the performance of 4H-SiC BJTs
- 2011
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Ingår i: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 58, s. 259-265
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Tidskriftsartikel (refereegranskat)abstract
- In this brief, the electrical performance in terms of maximum current gain and breakdown voltage is compared experimentally and by device simulation for 4H-SiC BJTs passivated with different surface-passivation layers. Variation in bipolar junction transistor (BJT) performance has been correlated to densities of interface traps and fixed oxide charge, as evaluated through MOS capacitors. Six different methods were used to fabricate SiO2 surface passivation on BJT samples from the same wafer. The highest current gain was obtained for plasma-deposited SiO2 which was annealed in N2O ambient at 1100 °C for 3 h. Variations in breakdown voltage for different surface passivations were also found, and this was attributed to differences in fixed oxide charge that can affect the optimum dose of the high-voltage junction-termination extension (JTE). The dependence of breakdown voltage on the dose was also evaluated through nonimplanted BJTs with etched JTE.
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- Östling, Mikael, et al.
(författare)
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SiC bipolar power transistors : Design and technology issues for ultimate performance
- 2010
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Ingår i: 2010 MRS Spring Meeting. - 9781605112237 ; , s. 175-186
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Konferensbidrag (refereegranskat)abstract
- Silicon carbide (SiC) semiconductor devices for high power are becoming more mature and are now commercially available as discrete devices. Schottky diodes have been on the market since a few years but also bipolar junction transistors (BJTs), JFETs and MOSFETs are now reaching the market. The interest is rapidly growing for these devices in high power and high temperature applications. The BJTs have low conduction losses, fast switching capability, operate in normally-off mode, have high radiation hardness, and can handle high power density.This paper will review the current state of the art in active switching device performance with special emphasis on BJTs. Device performance has been demonstrated over a wide temperature interval. A very important feature in high power switch applications is the low on-resistance of a device. Better material quality and epi processes suppress the amount of basal plane dislocations to avoid stacking fault formation generated during high current injection. This has long been a concern for bipolar SiC devices but several research reports and long term reliability measurements of pn-junctions show that the bipolar degradation problem can be solved by a fine-tuned epitaxial technique. A discussion on surface passivation control is included. Finally, an example of a power switching module is given also demonstrating the excellent paralleling capability of BJTs.
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