| 1. |
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| 2. |
- Danielsson, Åke, et al.
(författare)
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A controlled randomized trial of budesonide versus prednisolone retention enemas in active distal ulcerative colitis
- 1987
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 22:8, s. 987-992
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Tidskriftsartikel (refereegranskat)abstract
- Sixty-four patients with active distal ulcerative colitis participated in a multicentre, randomized, investigator-blind trial to compare the effect of budesonide enema, 2 mg/100 ml, with prednisolone disodium phosphate enema, 31.25 mg/100 ml. Budesonide is a new potent corticosteroid with a rapid first-pass elimination. The patients were treated for 4 weeks, and the efficacy of the drugs were evaluated by sigmoidoscopy, histology, and subjective symptoms after 2 and 4 weeks. After 4 weeks of treatment 16 of 31 patients (52%) receiving budesonide enema had healed endoscopically, compared with 8 of 33 (24%) (p = 0.045) receiving prednisolone enema. Budesonide was superior to prednisolone in terms of both significantly improved sigmoidoscopic and histologic scores and subjective symptoms evaluated by visual analogue scales. The patients receiving prednisolone had a significant depression of endogenous cortisol levels during the treatment period, but not the patients receiving budesonide. Budesonide enema seems to be a promising therapy for active distal ulcerative colitis and causes no adverse reactions
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| 3. |
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| 4. |
- Forsgren, Katarina, et al.
(författare)
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Deposition of HfO2 thin films in HfI4-based processes
- 2002
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 149:10, s. F139-F144
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Tidskriftsartikel (refereegranskat)abstract
- This study describes deposition of HfO2 thin films by chemical vapor deposition (CVD) and atomic layer deposition (ALD) using HfI4 as the metal precursor. The layer-by-layer growth was also studied in real time with a quartz crystal microbalance. In ALD, the deposition rate was independent of the growth temperature, whereas in CVD, an exponential rate increase was observed. Monoclinic HfO2 was deposited on MgO and poly-Si substrates in a wide temperature range, and the choice of substrate had a strong influence on the orientation of the films. Epitaxial growth of HfO2 was observed on MgO(001) substrates at 400-500°C in the ALD process and at 500-600°C in the CVD process. The electrical characterization showed that the crystallinity of the films had a stronger influence on the dielectric constant than did the film thickness.
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| 5. |
- Forsgren, Katarina, et al.
(författare)
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Iodide-Based Atomic Layer Deposition of ZrO2 : Aspects of Phase Stability and Dielectric Properties
- 2002
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Ingår i: Chemical Vapor Deposition. - 0948-1907 .- 1521-3862. ; 8:3, s. 105-109
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Tidskriftsartikel (refereegranskat)abstract
- This study is an investigation into the influence of temperature, substrate, and thickness on the properties of ZrO2 thin films grown by atomic layer deposition (ALD). ZrI4 and H2O2 were used as source materials, and films deposited at temperatures between 250 °C and 500 °C consisted of mixed tetragonal and monoclinic ZrO2. The phase content and electrical properties of films of 3–30 nm thickness were studied for different temperatures and substrates. The films crystallized at smaller thicknesses on the Pt/Ti/SiO2/Si (denoted Pt in the following text) substrate than on polycrystalline Si (poly-Si) and MgO(001). It was also found that the film thickness had a stronger effect on the dielectric constant than either the growth temperature or the substrate.
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| 6. |
- Gidhagen, Lars, et al.
(författare)
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Towards climate services for European cities : Lessons learnt from the Copernicus project Urban SIS
- 2020
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Ingår i: Urban Climate. - Amsterdam, Netherlands : Elsevier. - 2212-0955. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- The growing share of Europe's population living in cities makes urban climate change impact assessment and adaptation a critical issue. The urban environment is characterized by its sensitivity to small-scale meteorological, hydrological and environmental processes. These are generally not fully described in climate models, largely because of the models' insufficient spatial resolution. The Urban SIS climate service offers historical and future simulated data downscaled to 1 km × 1 km resolution over selected European metropolitan areas. The downscaled data are subsequently used as input to air quality and hydrological impact models, all made available to users as Essential Climate Variables and Sectoral Impact Indicators through a web portal. This paper presents the Urban SIS climate service and demonstrates its functionality in a case study in Stockholm city, Sweden. Good model performance was attained for intra-city temperature gradients and small-scale precipitation extremes. Less positive results were obtained for large-scale precipitation and hydrology, mainly due to an insufficient domain size in the meteorological and climate modelling, in turn related to the substantial computational requirements. An uncertainty classification approach was developed to aid the interpretation and user application of the data. We hope our lessons learnt will support future efforts in this direction.
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| 7. |
- Gjirja, Savo, 1945, et al.
(författare)
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Fischer- Tropsch-Synthesis Fuels as Diesel Engine Fuel-Fuel of the Future
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Fischer-Tropsch (F-T) catalytic conversion process can be used to synthesize diesel fuels from a variety of feed-stocks, including coal, natural gas and biomass. Synthetic diesel fuels can have very low sulfur and aromatic content, and excellent autoignition characteristics. Moreover, Fischer-Tropsch diesel fuels may also be economically competitive with regular diesel fuel if produced in large volumes.The aim of this investigation is to reveal and analyze the effects of F- T fuels on a research diesel engine performance. Previous engine laboratory tests indicate that F-T fuels are promising alternative fuels because they can be used in unmodified diesel engines, and substantial quantitative exhaust emission reductions can be reached. Also substantial qualitative reductions, e.g. reduction of the number of hazardous chemicals and reduction of the concentration of hazardous chemicals in the exhausts may be realized. Since the engine performance is close1y related to in-cylinder processes, a detailed thermodynamic analysis has been performed revealing the real thermo-chemistry history. The experimental results have shown that F-T fuels have a beneficial effect not only on the emissions levels, but also on other energetic parameters of the engine. Heat release analysis has shown that ignition delay, cylinder peak pressure, heat release gradient and indicated efficiency are affected as well.Two different mixtures of FT-fuels with variation in carbon chain branching and, to a certain extent variation in chain 1ength were tested and their results were compared with those obtained from conventional fuel (MK 1). The selected optimized F-T fuels mixture were further tested according to the 13 mode ECE R49 test cycle and were found as good competitive alternative diesel fuels.
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| 8. |
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| 9. |
- Olsson, Bengt, et al.
(författare)
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A decision support model for individual tree stump harvesting options based on criteria for economic return and environmental protection
- 2017
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Ingår i: Scandinavian Journal of Forest Research. - : Taylor & Francis Group. - 0282-7581 .- 1651-1891. ; 32, s. 246-259
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Tidskriftsartikel (refereegranskat)abstract
- Based on principles of multi-criteria analysis techniques, a model (MAPStump-E) for decision support on stump harvesting at stand level was developed. The model applies the concept that each stump can be attributed production values (economic) and environmental values (here soil protection and water quality). Individual tree stump information was incorporated directly from the production reports of harvesters and combined with high-resolution Geographical Information System data on topography and soil type to create a production submodel and a soil and water vulnerability submodel (SWM). To test the model, it was applied to a 45-ha study forest in south-central Sweden and the outcome of nine scenarios with varying bioenergy prices and environmental protection levels was examined. Combined analysis of the effects of production and environmental criteria on total dry mass of harvestable stumps at the study site showed that biomass prices had a stronger influence than environmental criteria. Conflict stumps were defined as stumps suitable for harvest based on production criteria, but unsuitable based on soil and water protection criteria. In a ?medium? price scenario, the proportion of conflict stumps at the study site ranged from 6% to 18%, depending on protection level set.
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| 10. |
- Ranius, Thomas, et al.
(författare)
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The effects of logging residue extraction for energy on ecosystem services and biodiversity : a synthesis
- 2018
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Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 209, s. 409-425
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Forskningsöversikt (refereegranskat)abstract
- We review the consequences for biodiversity and ecosystem services from the industrial-scale extraction of logging residues (tops, branches and stumps from harvested trees and small-diameter trees from thinnings) in managed forests. Logging residue extraction can replace fossil fuels, and thus contribute to climate change mitigation. The additional biomass and nutrients removed, and soils and other structures disturbed, have several potential environmental impacts. To evaluate potential impacts on ecosystem services and biodiversity we reviewed 279 scientific papers that compared logging residue extraction with non-extraction, the majority of which were conducted in Northern Europe and North America. The weight of available evidence indicates that logging residue extraction can have significant negative effects on biodiversity, especially for species naturally adapted to sun-exposed conditions and the large amounts of dead wood that are created by large-scaled forest disturbances. Slash extraction may also pose risks for future biomass production itself, due to the associated loss of nutrients. For water quality, reindeer herding, mammalian game species, berries, and natural heritage the results were complicated by primarily negative but some positive effects, while for recreation and pest control positive effects were more consistent. Further, there are initial negative effects on carbon storage, but these effects are transient and carbon stocks are mostly restored over decadal time perspectives. We summarize ways of decreasing some of the negative effects of logging residue extraction on specific ecosystem services, by changing the categories of residue extracted, and site or forest type targeted for extraction. However, we found that suggested pathways for minimizing adverse outcomes were often in conflict among the ecosystem services assessed. Compensatory measures for logging residue extraction may also be used (e.g. ash recycling, liming, fertilization), though these may also be associated with adverse environmental impacts.
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| 11. |
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| 12. |
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| 13. |
- Svanberg, Sune, et al.
(författare)
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Applications of terawatt lasers
- 1994
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Ingår i: LASER SPECTROSCOPY - XITH INTERNATIONAL CONFERENCE. - : AIP. - 1551-7616 .- 0094-243X. - 1563962624 ; :290, s. 264-269
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Konferensbidrag (refereegranskat)
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Westlinder, Jörgen, 1973-
(författare)
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Investigation of Novel Metal Gate and High-κ Dielectric Materials for CMOS Technologies
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The demands for faster, smaller, and less expensive electronic equipments are basically the driving forces for improving the speed and increasing the packing density of microelectronic components. Down-scaling of the devices is the principal method to realize these requests. For future CMOS devices, new materials are required in the transistor structure to enable further scaling and improve the transistor performance.This thesis focuses on novel metal gate and high-κ dielectric materials for future CMOS technologies. Specifically, TiN and ZrN gate electrode materials were studied with respect to work function and thermal stability. High work function, suitable for pMOS transistors, was extracted from both C-V and I-V measurements for PVD and ALD TiN in TiN/SiO2/Si MOS capacitor structures. ZrNx/SiO2/Si MOS capacitors exhibited n-type work function when the low-resistivity ZrNx was deposited at low nitrogen gas flow. Further, variable work function by 0.6 eV was achieved by reactive sputter depositing TiNx or ZrNx at various nitrogen gas flow. Both metal-nitride systems demonstrate a shift in work function after RTP annealing, which is discussed in terms of Fermi level pinning due to extrinsic interface states. Still, the materials are promising in a gate last process as well as show potential as complementary gate electrodes.The dielectric constant of as-deposited (Ta2O5)1-x(TiO2)x thin films is around 22, whereas that of AlN is about 10. The latter is not dependent on the degree of crystallinity or on the measurement frequency up to 10 GHz. Both dielectrics exhibit characteristics appropriate for integrated capacitors. Finally, utilization of novel materials were demonstrated in strained SiGe surface-channel pMOSFETs with an ALD TiN/Al2O3 gate stack. The transistors were characterized with standard I-V, charge pumping, and low-frequency noise measurements. Correlation between the mobility and the oxide charge was found. Improved transistor performance was achieved by conducting low-temperature water vapor annealing, which reduced the negative charge in the Al2O3.
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| 19. |
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Westlinder, Jörgen, et al.
(författare)
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Variable work function in MOS capacitors utilizing nitrogen-controlled TiNx gate electrodes
- 2004
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 75:4, s. 389-396
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Tidskriftsartikel (refereegranskat)abstract
- A substantial shift in the work function of TiNx by as much as 0.7 eV is achieved by varying the nitrogen gas flow during the reactive sputter deposition of the metal gate, which indicates tunability for replacing poly-Si in a CMOS process. TiNx MOS capacitors having multiple SiO2 thicknesses have been evaluated and the work function of TiNx can be altered from 4.2 to 4.9 eV depending on the nitrogen content. The values are stable after RTP annealing up to 600 °C in nitrogen gas for 30 s, although annealing at 800 °C changes the work function for the different compositions towards a mid-gap value. No variation in EOT with annealing temperature is observed for the TiNx/SiO2 stacks deposited at high nitrogen gas flow. The change in work function appears not to be correlated to the crystalline orientation of the TiNx. The work function is instead believed to be affected by extrinsic states in the metal/dielectric interface.
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| 26. |
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| 27. |
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| 28. |
- Abermann, S., et al.
(författare)
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Impact of Al-, Ni-, TiN-, and Mo-metal gates on MOCVD-grown HfO2 and ZrO2 high-k dielectrics
- 2007
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Ingår i: Microelectronics and reliability. - : Elsevier BV. - 0026-2714 .- 1872-941X. ; 47:4-5, s. 536-539
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Tidskriftsartikel (refereegranskat)abstract
- In this work we compare the impacts of nickel (Ni), titanium-nitride (TiN), molybdenum (Mo), and aluminium (Al), gates on MOS capacitors incorporating HfO2- or ZrO2-dielectrics. The primary focus lies on interface trapping, oxide charging, and thermodynamical stability during different annealing steps of these gate stacks. Whereas Ni, Mo, and especially TIN are investigated as most promising candidates for future CMOS devices, Al acted as reference gate material to benchmark the parameters. Post-metallization annealing of both, TiN- and Mo-stacks, resulted in very promising electrical characteristics. However, gate stacks annealed at temperatures of 800 degrees C or 950 degrees C show thermodynamic instability and related undesirable high leakage currents.
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| 29. |
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| 30. |
- Abermann, S., et al.
(författare)
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Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric
- 2007
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 84:5-8, s. 1635-1638
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate various metal gate/high-k/Si capacitors by their resulting electrical characteristics. Therefore, we process MOS gate stacks incorporating aluminium (Al), nickel (Ni), titanium-nitride (TiN), and molybdenum (Mo) as the gate material, and metal organic chemical vapour deposited (MOCVD) ZrO2 and HfO2 as the gate dielectric, respectively. The influence of the processing sequence - especially of the thermal annealing treatment - on the electrical characteristics of the various gate stacks is being investigated. Whereas post metallization annealing in forming gas atmosphere improves capacitance-voltage behaviour (due to reduced interface-, and oxide charge density), current-voltage characteristics degrade due to a higher leakage current after thermal treatment at higher temperatures. The Flatband-voltage values for the TiN-, Mo-, and Ni-capacitors indicate mid-gap pinning of the metal gates, however, Ni seems to be thermally unstable on ZrO2, at least within the process scheme we applied.
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| 31. |
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| 32. |
- Ahlberg, Patrik, et al.
(författare)
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A two-in-one process for reliable graphene transistors processed with photolithography
- 2015
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:20
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Tidskriftsartikel (refereegranskat)abstract
- Research on graphene field-effect transistors (GFETs) has mainly relied on devices fabricated using electron-beam lithography for pattern generation, a method that has known problems with polymer contaminants. GFETs fabricated via photo-lithography suffer even worse from other chemical contaminations, which may lead to strong unintentional doping of the graphene. In this letter, we report on a scalable fabrication process for reliable GFETs based on ordinary photo-lithography by eliminating the aforementioned issues. The key to making this GFET processing compatible with silicon technology lies in a two-in-one process where a gate dielectric is deposited by means of atomic layer deposition. During this deposition step, contaminants, likely unintentionally introduced during the graphene transfer and patterning, are effectively removed. The resulting GFETs exhibit current-voltage characteristics representative to that of intrinsic non-doped graphene. Fundamental aspects pertaining to the surface engineering employed in this work are investigated in the light of chemical analysis in combination with electrical characterization.
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| 33. |
- Ahlberg, Patrik, 1985-, et al.
(författare)
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Interface Dependent Effective Mobility in Graphene Field Effect Transistors
- 2018
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 47:3, s. 1757-1761
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Tidskriftsartikel (refereegranskat)abstract
- By pretreating the substrate of a graphene field-effect transistor (G-FET), a stable unipolar transfer characteristic, instead of the typical V-shape ambipolar behavior, has been demonstrated. This behavior is achieved through functionalization of the SiO2/Si substrate that changes the SiO2 surface from hydrophilic to hydrophobic, in combination with postdeposition of an Al2O3 film by atomic layer deposition (ALD). Consequently, the back-gated G-FET is found to have increased apparent hole mobility and suppressed apparent electron mobility. Furthermore, with addition of a top-gate electrode, the G-FET is in a double-gate configuration with independent top- or back-gate control. The observed difference in mobility is shown to also be dependent on the top-gate bias, with more pronounced effect at higher electric field. Thus, the combination of top and bottom gates allows control of the G-FET's electron and hole mobilities, i.e., of the transfer behavior. Based on these observations, it is proposed that polar ligands are introduced during the ALD step and, depending on their polarization, result in an apparent increase of the effective hole mobility and an apparent suppressed effective electron mobility.
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| 34. |
- Almered Olsson, Gunilla, 1951, et al.
(författare)
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Peri-Urban Food Production and Its Relation to Urban Resilience
- 2016
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Food production on the urban-rural fringe is under pressure due to competing land uses. We discuss the potential to improve resilience for urban-rural regions by enhancing food production as part of multifunctional land use. Through studies of peri-urban land in the regions of Gothenburg (Sweden), Copenhagen (Denmark) and Gent (Belgium), recent developments are analysed. Arable farming has been declining since 2000 in all three areas due to urban expansion and recreational land use changes. In city plans, networks of protected areas and green spaces and their importance for human wellbeing have been acknowledged. Policies for farmland preservation in peri-urban settings exist, but strategies for local food production are not expressed in present planning documents. Among the diversity of peri-urban agricultural activities, peri-urban food production is a developing issue. However, the competing forms of land use and the continuing high dependence of urban food on global food systems and related resource flows reduces peri-urban food production and improvements in urban food security. The positive effects of local food production need to be supported by governance aiming to improve the urban-rural relationship. The paper discusses the resilience potential of connecting urban-rural regions and re-coupling agriculture to regional food production.
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| 35. |
- Anchev, Stefan, 1986-
(författare)
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Information and financial markets
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The results in this thesis are consistent with the hypotheses that: 1) the incomplete dissemination of information across investors helps in explaining the occurrence and the persistence of cross-sectional stock return anomalies, 2) the properties of the investor base of a stock have implications for the informativeness of the stock's price and 3) a greater quantity of firm disclosure places less sophisticated investors at an information disadvantage. Overall, the thesis provides new empirical evidence about the role of information in financial markets.Investor Base and Stock Return AnomaliesAfter controlling for market capitalization, the predictability of future stock returns associated with each of the earnings-to-price ratio, the book-to-market ratio, the past return, the total volatility of returns and the return on assets is more pronounced among stocks with smaller total and/or institutional investor bases. These results appear even after controlling for several other stock characteristics and potential risk factors and they are both statistically and economically meaningful. Thus, they are consistent with the hypothesis that the incomplete dissemination of information across investors helps in explaining the occurrence and the persistence of cross-sectional stock return anomalies.Investor Base and Stock Price InformativenessThe relative idiosyncratic volatility of future stock returns is: 1) negatively associated with the absolute size of the total and the institutional investor base, 2) positively associated with the institutional ownership, 3) negatively (positively) associated with the average stock portfolio size (Herfindahl index) of the investor base and 4) positively associated with the indirect (i.e., through nominees) ownership. These results appear after controlling for several other stock characteristics and they are both statistically and economically meaningful. Thus, they are consistent with the hypothesis that the properties of the investor base of a stock have implications for the informativeness of the stock's price.Individual Investors and Quantity of Firm DisclosureWhen the amount of information disclosed by a firm is greater (or increases), the stock portfolio weights that individual investors allocate (through trading) to that firm's stock are lower (or decrease) and suboptimal. The former result is less pronounced or nonexistent for more financially competent individuals and for positions in firms with a poorer information environment. When they do allocate greater portfolio weights to the stock of a firm that discloses more, individuals, regardless of their financial competence, earn lower returns. Overall, these results are consistent with the hypothesis that a greater quantity of firm disclosure places less sophisticated investors at an information disadvantage.
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| 36. |
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| 37. |
- Andersson, Per, et al.
(författare)
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Utbildningsinsats för att höja den pedagogiska digitala kompetensen
- 2016
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Konferensbidrag (refereegranskat)abstract
- Under 2015 genomförde Medicinska fakulteten vid Umeå universitet en satsning för att höja den Pedagogiska Digitala Kompetensen (PDK) bland sina medarbetare i syfte att öka de digitala inslagen i undervisningen. En del i satsningen var att genomföra en utbildningsinsats. Uppdraget gavs till Pedagogiska institutionen som i samarbete med Universitetspedagogik och lärandestöd (UPL) genomförde ett antal seminarier under 2015. Deltagarna hade möjlighet att delta på plats i Umeå eller via nätet. Målsättningen var att varje seminarium skulle innehålla både teoretiska och praktiska inslag och en progression från inledande förmedlande information till allt fler deltagaraktiva inslag. Under hösten 2015 genomfördes även en workshop, som utgjorde en fördjupning där deltagarna med utgångspunkt i en fiktiv kursplan samt metoden flipped classroom utarbetade egna förslag till kursdesign och undervisningsaktiviteter med stöd av digital teknik. Exempel på digital teknik som deltagarna har fått ta del av eller själva arbeta med under utbildningsinsatsen är Moodle, Googleapps, Adobe connect, Socrative, Screen cast-o-matic och Prezi. En webbresurs har funnits tillgänglig som komplement till seminarieserien. Där har deltagarna haft tillgång till instruktioner, frågeställningar, föreläsningsfilmer samt de digitala presentationerna som hållits under seminarierna. Utöver detta har även ett s.k. bonusmaterial i form av länkar och frivilliga uppgifter tillhandahållits för de som varit intresserade att fördjupa sig inom exempelvis e-lärande i relation till pedagogisk meritering. Totalt medverkade ca 100 deltagare, som representerade 20 utbildningsprogram på fakulteten, i utbildningsinsatsen. Utvärderingen av insatsen visar att majoriteten av deltagare upplever att de höjt sin pedagogiska digitala kompetens i hög eller mycket hög utsträckning. De uttrycker även att de tillägnat sig generella kunskaper, vilket ses som en viktig grund för det egna arbetet med att öka de digitala inslagen i undervisningen. En annan framträdande synpunkt är att de praktiska och exemplifierande inslagen har uppfattats som betydligt mer värdefulla från ett lärandeperspektiv än de inledande teoretiskt inriktade inslagen. Resultatet visar också att majoriteten anser att de ökat sina kunskaper om digitala resurser och verktyg som kan användas i undervisningen. Även webbresursen har använts flitigt. Utvärderingen visar att majoriteten anser att webbresursen varit ett bra komplement till seminarieserien. Detta återspeglas också i de loggdata som visar på relativt omfattande besöksfrekvenser. Att seminariematerialet fanns samlat på ett ställe och tillgängligt för deltagarna före och efter seminarierna har haft stor betydelse för deltagarna. Därmed underlättades deras förberedelser inför seminarierna och möjligheten gavs att i efterhand repetera och ytterligare fördjupa sina kunskaper.Sammanfattningsvis visar resultaten från utvärderingen att målen med utbildningsinsatsen uppnåtts på ett tillfredsställande sätt, och att satsningen sålunda fallit väl ut. En aspekt som inte framkommit ovan men som är värd att lyftas fram är det faktum att ett flertal kommentarer i utvärderingarna handlar om ett ökande intresse för, och en ökande nyfikenhet på, att integrera digitala inslag i sin egen undervisningspraktik i större utsträckning än tidigare. Den samlade bedömningen är att Medicinsk fakultet vid Umeå universitet i och med denna satsning lagt en mycket god grund för fortsatta utvecklingsarbeten avseende PDK.
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| 38. |
- Andersson, Per, et al.
(författare)
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Utbildningsinsats för att höja den pedagogiskt digitala kompetensen
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Under 2015 genomförde Medicinska fakulteten vid Umeå universitet en satsning för att höja den Pedagogiska Digitala Kompetensen (PDK) bland sina medarbetare i syfte att öka de digitala inslagen i undervisningen. En del i satsningen var att genomföra en utbildningsinsats. Uppdraget gavs till Pedagogiska institutionen som i samarbete med Universitetspedagogik och lärandestöd (UPL) genomförde ett antal seminarier under 2015. Deltagarna hade möjlighet att delta på plats i Umeå eller via nätet. Målsättningen var att varje seminarium skulle innehålla både teoretiska och praktiska inslag och en progression från inledande förmedlande information till allt fler deltagaraktiva inslag. Under hösten 2015 genomfördes även en workshop, som utgjorde en fördjupning där deltagarna med utgångspunkt i en fiktiv kursplan samt metoden flipped classroom utarbetade egna förslag till kursdesign och undervisningsaktiviteter med stöd av digital teknik. Exempel på digital teknik som deltagarna har fått ta del av eller själva arbeta med under utbildningsinsatsen är Moodle, Googleapps, Adobe connect, Socrative, Screen cast-o-matic och Prezi.En webbresurs har funnits tillgänglig som komplement till seminarieserien. Där har deltagarna haft tillgång till instruktioner, frågeställningar, föreläsningsfilmer samt de digitala presentationerna som hållits under seminarierna. Utöver detta har även ett s.k. bonusmaterial i form av länkar och frivilliga uppgifter tillhandahållits för de som varit intresserade att fördjupa sig inom exempelvis e-lärande i relation till pedagogisk meritering.Totalt medverkade ca 100 deltagare, som representerade 20 utbildningsprogram på fakulteten, i utbildningsinsatsen. Utvärderingen av insatsen visar att majoriteten av deltagare upplever att de höjt sin pedagogiska digitala kompetens i hög eller mycket hög utsträckning. De uttrycker även att de tillägnat sig generella kunskaper, vilket ses som en viktig grund för det egna arbetet med att öka de digitala inslagen i undervisningen. En annan framträdande synpunkt är att de praktiska och exemplifierande inslagen har uppfattats som betydligt mer värdefulla från ett lärandeperspektiv än de inledande teoretiskt inriktade inslagen. Resultatet visar också att majoriteten anser att de ökat sina kunskaper om digitala resurser och verktyg som kan användas i undervisningen.Även webbresursen har använts flitigt. Utvärderingen visar att majoriteten anser att webbresursen varit ett bra komplement till seminarieserien. Detta återspeglas också i de loggdata som visar på relativt omfattande besöksfrekvenser. Att seminariematerialet fanns samlat på ett ställe och tillgängligt för deltagarna före och efter seminarierna har haft stor betydelse för deltagarna. Därmed underlättades deras förberedelser inför seminarierna och möjligheten gavs att i efterhand repetera och ytterligare fördjupa sina kunskaper.Sammanfattningsvis visar resultaten från utvärderingen att målen med utbildningsinsatsen uppnåtts på ett tillfredsställande sätt, och att satsningen sålunda fallit väl ut. En aspekt som inte framkommit ovan men som är värd att lyftas fram är det faktum att ett flertal kommentarer i utvärderingarna handlar om ett ökande intresse för, och en ökande nyfikenhet på, att integrera digitala inslag i sin egen undervisningspraktik i större utsträckning än tidigare. Den samlade bedömningen är att Medicinsk fakultet vid Umeå universitet i och med denna satsning lagt en mycket god grund för fortsatta utvecklingsarbeten avseende PDK.
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| 39. |
- Anderås, Emil, 1982-
(författare)
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Advanced MEMS Pressure Sensors Operating in Fluids
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today’s MEMS technology allows manufacturing of miniaturized, low power sensors that sometimes exceeds the performance of conventional sensors. The pressure sensor market today is dominated by MEMS pressure sensors.In this thesis two different pressure sensor techniques are studied. The first concerns ways to improve the sensitivity in the most commonly occurring pressure sensor, namely such based on the piezoresistive technique. Since the giant piezoresistive effect was observed in silicon nanowires, it was assumed that a similar effect could be expected in nano-thin silicon films. However, it turned out that the conductivity was extremely sensitive to substrate bias and could therefore be controlled by varying the backside potential. Another important parameter was the resistivity time drift. Long time measurements showed a drastic variation in the resistance. Not even after several hours of measurement was steady state reached. The drift is explained by hole injection into the buried oxide as well as existence of mobile charges. The piezoresistive effect was studied and shown to be of the same magnitude as in bulk silicon. Later research has shown the existence of such an effect where the film thickness has to be less than around 20 nm. The second area that has been studied is the pressure sensitivity of in acoustic resonators. Aluminium nitride thin film plate acoustic resonators (FPAR) operating at the lowest-order symmetric (S0), the first-order asymmetric (A1) as well as the first-order symmetric (S1) Lamb modes have been theoretically and experimentally studied in a comparative manner. The S0 Lamb mode is identified as the most pressure sensitive FPAR mode. The theoretical predictions were found to be in good agreement with the experiments. Additionally, the Lamb modes have been tested for their sensitivities to mass loading and their ability to operate in liquids, where the S0 mode showed good results.Finally, the pressure sensitivity in aluminium nitride thin film bulk wave resonators employing c- and tilted c-axis texture has been studied. The c-axis tilted FBAR demonstrates a substantially higher pressure sensitivity compared to its c-axis oriented counterpart.
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| 40. |
- Anderås, Emil, et al.
(författare)
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Drift in thin film SOI piezoresistors
- 2010
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Ingår i: Proc. of EUROSOI Workshop, 2010 Jan 25-27, Grenoble, France. ; , s. 71-72
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Konferensbidrag (refereegranskat)
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| 46. |
- Ankarcrona, Johan, 1971-
(författare)
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High Frequency Analysis of Silicon RF MOS Transistors
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today, the silicon technology is well established for RF-applications (f~1-100 GHz), with emphasis on the lower frequencies (f < 5 GHz). The field of RF power devices is extensive concerning materials and devices. One of the important RF-devices is the silicon LDMOS transistor. A large extent of the research presented in the thesis concerns studies of this device, which have resulted in increased understanding of the device behavior and improved performance. The thesis starts with a brief survey of the RF-field, including the LDMOS transistor, followed by a description of the methods used in the investigations; simulations, modeling and measurements. Specific results presented in the appended papers are also briefly summarized. A new concept for LDMOS transistors, which allows for both high frequency and high voltage operation, has been developed and characterized. World-record performance in terms of output power density was obtained: over 1 W/mm at 50 V and 3.2 GHz. Further understanding and improvements of the device are achieved using simulations and modeling. For determination of model parameters a new general parameter extraction technique was developed. The method has been successfully used for a large variety of high-frequency devices, and has been frequently used in the modeling work in this thesis. Important properties of RF-power devices are the device linearity and power efficiency. Extensive studies regarding the efficiency were conducted using numerical simulations and modeling of the off-state output resistance, which is correlated to the efficiency. The results show that significant improvements can be obtained for devices on both bulk- and SOI-substrates, using thin high-resistivity substrates and very low-resistivity SOI-substrates, respectively. Finally a new approach to drastically reduce substrate crosstalk by using very low-resistivity SOI substrate is proposed. Experimentally, a reduction of 20-40 dB was demonstrated in the GHz range compared to high-resistivity SOI substrate.
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