1. |
- Ahlberg, Erik, et al.
(författare)
-
"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
-
Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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2. |
- Ahlbeck Bergendahl, Ida, et al.
(författare)
-
Fisk- och skaldjursbestånd i hav och sötvatten 2016 : Resursöversikt
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES).De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.Rapporten omfattar 41 fiskarter uppdelade i olika bestånd, samt sju skal- och blötdjursarter.Nytt för årets upplaga är kapitlet om ekosystemtjänster. Avsnittet beskriver de fördelar människan får genom ekosystemen, till exempel hur fisk och skaldjur kommer till nytta för människan genom föda, rekreation och biologisk mångfald. Nytt för i år är också att rapportens diagram och figurer anpassats för läsare med defekt färgseende.Översikten är utarbetad av SLU Aqua på uppdrag av Havs- och vattenmyndigheten.
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3. |
- Almqvist, Erik, et al.
(författare)
-
Increased plasma concentrations of N-terminal pro-B-type natriuretic peptide in patients with mild primary hyperparathyroidism.
- 2006
-
Ingår i: Clinical endocrinology. - : Wiley. - 0300-0664 .- 1365-2265. ; 65:6, s. 760-6
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Primary hyperparathyroidism (PHPT) is associated with heart disease. The aims of the present study were to evaluate how cardiac function and secretion of N-terminal pro-B-type natriuretic peptide (NT-proBNP) correlate in patients with mild PHPT, and how the plasma level of NT-proBNP is influenced by cure of the parathyroid disease. DESIGN AND PATIENTS: Forty-two patients with PHPT without symptoms of heart disease were examined before and 1 year after curative parathyroidectomy. MEASUREMENTS: Plasma or serum concentrations of NT-proBNP, calcium, PTH, creatinine, oestradiol, testosterone and SHBG were measured. Cardiac function was evaluated by equilibrium radionuclide angiography (ERNA). RESULTS: At baseline, NT-proBNP levels correlated negatively with systolic function [left ventricular ejection fraction (LVEF), P < 0.001]. Twelve per cent of the patients had NT-proBNP levels above normal reference values preoperatively. One year postoperatively, the corresponding proportion was 21%. The mean plasma concentration of NT-proBNP increased after parathyroidectomy (P < 0.01) in parallel with a dip in diastolic function (peak filling rate, P < 0.05) and a falling trend in systolic function (LVEF, P = 0.08). The postoperative percentage changes in circulating NT-proBNP and total oestradiol correlated positively (P < 0.05). CONCLUSIONS: Patients with mild PHPT and normal renal function may have high levels of circulating NT-proBNP despite the absence of symptomatic heart disease. Cure of the parathyroid disease is followed by a further increase in NT-proBNP secretion in parallel with ERNA measures, indicating subclinical changes in heart function. These results are in line with data indicating an association between PHPT and increased risk of premature death.
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4. |
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5. |
- Andric, Stefan, et al.
(författare)
-
Performance, Analysis, and Modeling of III-V Vertical Nanowire MOSFETs on Si at Higher Voltages
- 2022
-
Ingår i: IEEE Transactions on Electron Devices. - 0018-9383. ; 69:6, s. 3055-3055
-
Tidskriftsartikel (refereegranskat)abstract
- Heterostructure engineering in III-V vertical nanowire (VNW) MOSFETs enables tuning of transconductance and breakdown voltage. In this work, an InxGa 1−x As channel with a Ga-composition grading ( x= 1–0.4) in the channel and drain region, combined with field plate engineering, enables breakdown voltage above 2.5 V, while maintaining transconductance of about 1 mS/ μm , in VNW MOSFETs. The field plate consists of a vertically integrated SiO2 layer and a gate contact, which screens the electric field in the drain region, extending the device operating voltage. By scaling the field plate, a transconductance of 2 mS/ μm , alongside the breakdown voltage of 1.5 V, is obtained, demonstrating the benefit of field engineering in the drain. The scalability of the field plate and the gate is measured, showing an ON-resistance increase by 23 Ω⋅μm , and transconductance decrease by 5 μS/μm , per nm field plate length. This behavior is captured in a new and modified virtual source model, where device transmission and drain resistance are altered to capture the field plate scaling effect. The modeling is applied to nanowire (NW) devices with field plate lengths ranging from 5 to 115 nm, capturing accurately essential device performance parameters. Finally, a modified band-to-band (BTB) tunneling approach is used to accurately describe the device behavior above 1.5 V.
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6. |
- Babadi, Aein S., et al.
(författare)
-
Impact of doping and diameter on the electrical properties of GaSb nanowires
- 2017
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:5
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of doping and diameter on the electrical properties of vapor-liquid-solid grown GaSb nanowires was characterized using long channel back-gated lateral transistors and top-gated devices. The measurements showed that increasing the doping concentration significantly increases the conductivity while reducing the control over the channel potential and shifting the threshold voltage, as expected. The highest average mobility was 85 cm2/V·s measured for an unintentionally doped GaSb nanowire with a diameter of 45 nm, whereas medium doped nanowires with large diameters (81 nm) showed a value of 153 cm2/V·s. The mobility is found to be independent of nanowire diameter in the range of 36 nm-68 nm, while the resistivity is strongly reduced with increasing diameter attributed to the surface depletion of charge carriers. The data are in good agreement with an analytical calculation of the depletion depth. A high transconductance was achieved by scaling down the channel length to 200 nm, reaching a maximum value of 80 μS/μm for a top-gated GaSb nanowires transistor with an ON-resistance of 26 kΩ corresponding to 3.9 Ω.mm. The lowest contact resistance obtained was 0.35 Ω·mm for transistors with the highest doping concentration.
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7. |
- Belitsky, Victor, 1955, et al.
(författare)
-
Facility Heterodyne Receiver for the Atacama Pathfinder Experiment Telescope
- 2007
-
Ingår i: Proceedings of Joint 32nd International Conference on Infrared Millimeter Waves and 15th International conference on Terahertz Electronics, Sept 3-7, 2007, City Hall, Cardiff, Wales, UK. ; , s. 326-328
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Konferensbidrag (refereegranskat)
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8. |
- Bengtsson, Kenneth, et al.
(författare)
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Så kan Sverige bli ledande nation i resurseffektivitet
- 2016
-
Ingår i: Dagens Nyheter. - 1101-2447. ; :2016-04-30
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Ny rapport. Det svenska näringslivet kan bli mer hållbart, resurssmart och därmed internationellt konkurrenskraftigt. Men för det behövs en tydlig politisk avsiktsförklaring och riktlinjer. Vi har listat sex områden där policyutveckling brådskar, skriver företrädare för näringsliv, forskning och myndigheter i en gemensam uppmaning.
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9. |
- Berg, Martin, et al.
(författare)
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A transmission line method for evaluation of vertical InAs nanowire contacts
- 2015
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:23
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a method for metal contact characterization to vertical semiconductor nanowires using the transmission line method (TLM) on a cylindrical geometry. InAs nanowire resistors are fabricated on Si substrates using a hydrogen silsesquioxane (HSQ) spacer between the bottom and top contact. The thickness of the HSQ is defined by the dose of an electron beam lithography step, and by varying the separation thickness for a group of resistors, a TLM series is fabricated. Using this method, the resistivity and specific contact resistance are determined for InAs nanowires with different doping and annealing conditions. The contacts are shown to improve with annealing at temperatures up to 300 degrees C for 1min, with specific contact resistance values reaching down to below 1 Omega mu m(2). (C) 2015 AIP Publishing LLC.
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10. |
- Berg, Martin, et al.
(författare)
-
Electrical Characterization and Modeling of Gate-Last Vertical InAs Nanowire MOSFETs on Si
- 2016
-
Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 37:8, s. 966-969
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Tidskriftsartikel (refereegranskat)abstract
- Vertical InAs nanowire transistors are fabricated on Si using a gate-last method, allowing for lithography-based control of the vertical gate length. The best devices combine good ON- and OFF-performance, exhibiting an ON-current of 0.14 mA/μm, and a sub-threshold swing of 90 mV/dec at 190 nm LG. The device with the highest transconductance shows a peak value of 1.6 mS/μm. From RF measurements, the border trap densities are calculated and compared between devices fabricated using the gate-last and gate-first approaches, demonstrating no significant difference in trap densities. The results thus confirm the usefulness of implementing digital etching in thinning down the channel dimensions.
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11. |
- Berg, Martin, et al.
(författare)
-
Self-aligned, gate-last process for vertical InAs nanowire MOSFETs on Si
- 2016
-
Ingår i: Technical Digest - International Electron Devices Meeting, IEDM. - 9781467398930 ; 2016-February
-
Konferensbidrag (refereegranskat)abstract
- In this work, we present a novel self-aligned gate-last fabrication process for vertical nanowire metal-oxide-semiconductor field-effect transistors. The fabrication method allows for exposure dose-defined gate lengths and a local diameter reduction of the intrinsic channel segment, while maintaining thicker highly doped access regions. Using this process, InAs nanowire transistors combining good on-and off-performance are fabricated demonstrating Q = gm,max/SS = 8.2, which is higher than any previously reported vertical nanowire MOSFET.
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12. |
- Bertilsson, Erik, et al.
(författare)
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Use of digital human modelling and consideration of anthropometric diversity in Swedish industry
- 2010
-
Ingår i: Proceedings of the 42nd annual Nordic Ergonomic Society Conference. - 9788299574723
-
Konferensbidrag (refereegranskat)abstract
- This paper study and clarify problems, needs and opportunities when working with anthropometric diversity in digital human modelling (DHM) systems. A comparison between product development and production development in Swedish automotive industry is made. Interviews with DHM users and ergonomics specialists about their way of working with anthropometric diversity confirmed that simulations are often done with only one or a few human models. The reason for this is claimed to be time consuming processes, both at the creation of the human model but mainly when correctly positioning the model in the CAD environment.
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13. |
- Carlsson, Georg, et al.
(författare)
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Artrika vallar ger hållbar energiråvara och gynnar den biologiska mångfalden
- 2015
-
Ingår i: LTV-fakultetens faktablad.
-
Annan publikation (populärvet., debatt m.m.)abstract
- Detta faktablad utgör slutrapport för projektet "Användning av outnyttjade gräsmarker för biodiversitet och bioenergi - nätverk och fältförsök", som har genomförts under 2011-2014. Projektet har fört samman många aktörer med intresse för jordbruk, naturvård och bioenergi, och visat att nyetablering och extensiv hävd av artrika vallar kan generera värdefulla synergieffekter mellan minskad klimatpåverkan, minskad övergödning och ett rikt odlingslandskap.
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14. |
- Carlsson, Georg, et al.
(författare)
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Perennial species mixtures for multifunctional production of biomass on marginal land
- 2017
-
Ingår i: GCB Bioenergy. - : Wiley. - 1757-1693 .- 1757-1707. ; 9:1, s. 191-201
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional agriculture provides noncommodity functions and services along with food, feed and bioenergy feedstocks, for example by preserving or promoting biodiversity, improving soil fertility, mitigating climate change and environmental degradation, and contributing to the socio-economic viability of rural areas. Producing biomass for bioenergy from low-input perennial species mixtures on marginal land has the potential to support biodiversity and soil carbon sequestration in synergy with greenhouse gas mitigation. We compared biomass production in species-rich mixtures of perennial grasses, legumes and forbs with pure-stand grasses and relatively species-poor mixtures under different nitrogen fertilization regimes. Field experiments were performed on different types of marginal land, that is agricultural field margins and land with poor soil fertility, at four sites in southernmost and western Sweden. Biomass production was measured for three years in perennial grasses grown as pure stands, in legume-grass mixtures, and legume-grass-forb mixtures across a species richness gradient. In unfertilized species-rich mixtures, average biomass yields per experimental site and year were in the range from 3 to 9 metric ton DM ha−1 yr−1. While the most productive pure-stand grasses fertilized with 60–120 kg N ha−1 yr−1 often produced higher biomass yields than unfertilized mixtures, these differences were generally smaller than the variations between years and sites. Calculations of climate impact using the harvested biomass for conversion to biogas as vehicle fuel showed that the average greenhouse gas emissions per energy unit were about 50% lower in unfertilized systems than in treatments fertilized with 100–120 kg N ha−1 yr−1. Our findings thereby show that unfertilized species-rich perennial plant mixtures on marginal land provide resource-efficient biomass production and contribute to the mitigation of climate change. Perennial species mixtures managed with low inputs thus promote synergies between productivity and biodiversity in the perspective of climate-smart and multifunctional biomass production.
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15. |
- Chen, X., et al.
(författare)
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A genome-wide association study of IgM antibody against phosphorylcholine: shared genetics and phenotypic relationship to chronic lymphocytic leukemia
- 2018
-
Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 27:10, s. 1809-1818
-
Tidskriftsartikel (refereegranskat)abstract
- Phosphorylcholine (PC) is an epitope on oxidized low-density lipoprotein (oxLDL), apoptotic cells and several pathogens like Streptococcus pneumoniae. Immunoglobulin M against PC (IgM anti-PC) has the ability to inhibit uptake of oxLDL by macrophages and increase clearance of apoptotic cells. From our genome-wide association studies (GWASs) in four European-ancestry cohorts, six single nucleotide polymorphisms (SNPs) in 11q24.1 were discovered (in 3002 individuals) and replicated (in 646 individuals) to be associated with serum level of IgM anti-PC (the leading SNP rs35923643-G, combined beta = 0.19, 95% confidence interval 0.13-0.24, P = 4.3 x 10-11). The haplotype tagged by rs35923643-G (or its proxy SNP rs735665-A) is also known as the top risk allele for chronic lymphocytic leukemia (CLL), and a main increasing allele for general IgM. By using summary GWAS results of IgM anti-PC and CLL in the polygenic risk score (PRS) analysis, PRS on the basis of IgM anti-PC risk alleles positively associated with CLL risk (explained 0.6% of CLL variance, P = 1.2 x 10-15). Functional prediction suggested that rs35923643-G might impede the binding of Runt-related transcription factor 3, a tumor suppressor playing a central role in the immune regulation of cancers. Contrary to the expectations from the shared genetics between IgM anti-PC and CLL, an inverse relationship at the phenotypic level was found in a nested case-control study (30 CLL cases with 90 age- and sex-matched controls), potentially reflecting reverse causation. The suggested function of the top variant as well as the phenotypic association between IgM anti-PC and CLL risk needs replication and motivates further studies.
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16. |
- Davidsson, Kent, 1967, et al.
(författare)
-
Potassium, chlorine, and sulfur in ash, particles, deposits, and corrosion during wood combustion in a circulating fluidized-bed boiler
- 2007
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 21:1, s. 71-81
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the addition of chlorine and/or sulfur to the fuel on fly ash composition, deposit formation, and superheater corrosion has been studied during biomass combustion in a circulating fluidized-bed boiler. The chlorine (HCl (aq)) and sulfur (SO2 (g)) were added in proportions of relevance for the potassium chemistry. The composition of the bottom and the fly ashes was analyzed. Gas and particle measurements were performed downstream of the cyclone before the convection pass and the flue gas composition was recorded in the stack with a series of standard instruments and an FTIR analyzer. At the position downstream of the cyclone, a deposit probe was situated, simulating a superheater tube. Deposits on the probe and initial corrosion were examined. It is concluded that addition of sulfur and chlorine increases the formation of submicron particles leading to deposition of potassium sulfate and chloride. The results compare well with earlier work based on laboratory-scale experiments concerning effects of chlorine and sulfur on potassium chemistry.
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17. |
- Dey, Anil, et al.
(författare)
-
Combining axial and radial nanowire heterostructures: Radial Esaki diodes and tunnel field-effect transistors
- 2013
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 13:12, s. 5919-5924
-
Tidskriftsartikel (refereegranskat)abstract
- The ever-growing demand on high-performance electronics has generated transistors with very impressive figures of merit. The continued scaling of the supply voltage of field-effect transistors, such as tunnel field-effect transistors (TFETs), requires the implementation of advanced transistor architectures including FinFETs and nanowire devices. Moreover, integration of novel materials with high electron mobilities, such as III-V semiconductors and graphene, are also being considered to further enhance the device properties. In nanowire devices, boosting the drive current at a fixed supply voltage or maintaining a constant drive current at a reduced supply voltage may be achieved by increasing the cross-sectional area of a device, however at the cost of deteriorated electrostatics. A gate-all-around nanowire device architecture is the most favorable electrostatic configuration to suppress short channel effects, however, the arrangement of arrays of parallel vertical nanowires to address the drive current predicament will require additional chip area. The use of a core-shell nanowire with a radial heterojunction in a transistor architecture provides an attractive means to address the drive current issue without compromising neither chip area nor device electrostatics. In addition to design advantages of a radial transistor architecture, we in this work illustrate the benefit in terms of drive current per unit chip area and compare the experimental data for axial GaSb/InAs Esaki diodes and TFETs to their radial counterparts and normalize the electrical data to the largest cross-sectional area of the nanowire, i.e. the occupied chip area, assuming a vertical device geometry. Our data on lateral devices show that radial Esaki diodes deliver almost 7 times higher peak current, Jpeak = 2310 kA/cm2, than the maximum peak current of axial GaSb/InAs(Sb) Esaki diodes per unit chip area. The radial TFETs also deliver high peak current densities Jpeak = 1210 kA/cm2 while their axial counterparts at most carry Jpeak = 77 kA/cm2, normalized to the largest cross-sectional area of the nanowire.
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18. |
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19. |
- Dey, Anil, et al.
(författare)
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GaSb nanowire pFETs for III-V CMOS
- 2013
-
Ingår i: IEEE Device Research Conference. Proceedings. - 1548-3770. ; , s. 13-14
-
Konferensbidrag (refereegranskat)
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20. |
- Folkeson, Nicklas, 1981, et al.
(författare)
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Fireside corrosion of stainless and low alloyed steels in a waste-fired CFB boiler; The effect of adding sulphur to the fuel
- 2008
-
Ingår i: Materials Science Forum. ; 595-598, s. 289-297
-
Tidskriftsartikel (refereegranskat)abstract
- Corrosion field tests have been carried out in the superheater region of a commercial waste-fired 75MW CFBC boiler using air cooled probes. Exposure time was 24 and 1000 hours. The effect of adding sulphur to the fuel on the corrosion of two high alloyed steels and a low alloyed steel was studied. The fuel consisted of 50% household waste and 50% industrial waste. The exposed samples were analyzed by ESEM/EDX and XRD. Metal loss was determined after 1000 hours. Both materials suffered significant corrosion in the absence of sulphur addition and the addition of sulphur to the fuel reduced corrosion significantly. The rapid corrosion of the high alloyed steel in the absence of sulphur addition is caused by the destruction of the chromium-containing protective oxide by formation of calcium chromate. Adding sulphur to the fuel inhibited chromate formation and increased the sulphate/chloride ratio in the deposit. Iron(II) chloride formed on the low alloyed steel regardless of whether sulphur was added or not.
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21. |
- Froitzheim, Jan, 1981, et al.
(författare)
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Chromium evaporation of Coated and uncoated FE-22CR steels investigated by a novel denuder technique
- 2009
-
Ingår i: 3rd European Fuel Cell Technology and Applications - Piero Lunghi Conference, EFC 2009; Rome; Italy; 15 December 2009 through 18 December 2009. - 9788882862114 ; , s. 77-78
-
Konferensbidrag (refereegranskat)abstract
- The formation of volatile chromium species is a major problem concerning metallic interconnects for Solid Oxide Fuel Cells (SOFC). This problem is known and a number of routes, usually in the form of coatings, has been presented to overcome this problem. This paper investigates the influence of thin metallic films which can be applied by a low cost process. The measurements are carried out by a novel denuder technique where volatile chromium species are collected as sodium chromate. This technique allows the quantification of chromium evaporation in a time resolved manner. Coated and uncoated samples of ferritic steels developed for SOFC applications are investigated at 850°C in a N2-O2-H2O environment.
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22. |
- Froitzheim, Jan, 1981, et al.
(författare)
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Cr evaporation of metallic interconnects: A novel method for quantification
- 2009
-
Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781566777391 ; 25:2 PART 2, s. 1423-1428
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Konferensbidrag (refereegranskat)abstract
- Chromium evaporation from metallic interconnects in SOFCs is commonly poisoning the cathode of SOFCs. To reduce chromium evaporation, rather thick coatings have been deposited using various coating techniques. In this study, a 22% Cr ferritic steel has been coated with thin films (
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23. |
- Froitzheim, Jan, 1981, et al.
(författare)
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Investigation of Chromium Volatilization from FeCr Interconnects by a Denuder Technique
- 2010
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 157:9, s. B1295-B1300
-
Tidskriftsartikel (refereegranskat)abstract
- A technique is presented for accurate and time-resolved quantification of chromium volatilization from alloys at high temperature. A denuder tube which is coated with Na2CO3 is placed downstream of the samples. CrO2(OH)(2) that evaporated from the samples is collected on the denuder and converted to the thermally stable Na2CrO4. The chromate is then dissolved in water and determined quantitatively. Three commercially available ferritic 22% Cr steels intended for use as solid oxide fuel cell interconnect materials (Sanergy HT, Crofer 22 APU, and ZMG 232) have been investigated with respect to chromium volatilization and oxidation rate. The effect on chromium volatilization of a submicrometer cobalt coating on the steel surface is reported. Comparisons are made with a conventional thick ceramic coating. The experiments are carried out at 850 degrees C in N-2 - 20% O-2 - 3% H2O atmosphere. The submicrometer Co coatings proved to be very efficient, reducing Cr volatilization by 1 order of magnitude. Microscopic studies show that both uncoated steel and steel coated with a submicrometer cobalt film develop two-layered oxide scales with the bottom part consisting of a Cr-rich corundum-type oxide. The uncoated samples develop a top layer consisting of (Cr, Mn)(3)O-4 oxide, whereas the Co-coated samples exhibit a top layer consisting of Co-rich spinel oxide. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3462987] All rights reserved.
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24. |
- Fröberg, Linus, et al.
(författare)
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Vertical InAs nanowire wrap-gate FETs
- 2006
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Ingår i: Book of abstracts: Semicond Nanowires Symp, Eindhoven, The Netherlands (2006).
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Konferensbidrag (refereegranskat)
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25. |
- Gallo, Yann, et al.
(författare)
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Investigation of Late-Cycle Soot Oxidation Using Laser Extinction and In-Cylinder Gas Sampling at Varying Inlet Oxygen Concentrations in Diesel Engines
- 2017
-
Ingår i: Fuel. - : Elsevier BV. - 1873-7153 .- 0016-2361. ; 193, s. 308-314
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the relative importance of O2 and OH as oxidizers of soot during the late cycle in diesel engines, where the soot oxidation is characterized in an optically accessible engine using laser extinction measurements. These are combined with in cylinder gas sampling data from a single cylinder engine fitted with a fast gas sampling valve. Both measurements confirm that the in-cylinder soot oxidation slows down when the inlet concentration of O2 is reduced. A 38% decrease in intake O2 concentration reduces the soot oxidation rate by 83%, a non-linearity suggesting that O2 in itself is not the main soot oxidizing species. Chemical kinetics simulations of OH concentrations in the oxidation zone and estimates of the OH soot oxidation rates point towards OH being the dominant oxidizer.
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26. |
- Gissén, Charlott, et al.
(författare)
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Comparing energy crops for biogas production Yields, energy input and costs in cultivation using digestate and mineral fertilisation
- 2014
-
Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 64, s. 199-210
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of six crops grown in southern Sweden for biogas production (hemp, sugar beet, maize, triticale, grass/clover ley, winter wheat) showed varying performance regarding methane yield per hectare and energy input and costs in the production and supply of crops as biogas feedstock. The highest biomass and biogas yield was observed for sugar beet. Crops with lower risk of negative environmental impact in cultivation, such as ley and hemp, produced less than half the methane energy yield per hectare. Triticale, also having less risk of negative environmental impact, gave an energy yield similar to that of winter wheat grain and maize. Replacing most of the mineral fertiliser with biogas digestate did not, with the exception for hemp, influence crop yields per hectare, but energy input in cultivation decreased by on average 34% for the six crops tested. For hemp and sugar beet the biogas feedstock costs for the freshly harvested crop per GJ methane were close to that of the economic reference crop, winter wheat grain. For maize, beet tops and first and second year ley, the feedstock costs were lower, and for triticale much lower. When ensiled crops were used for biogas the feedstock costs increased and only those of triticale silage remained slightly lower than the cost of dried wheat grain. However, all feedstock costs were so high that profitable biogas production based solely on ensiled crops would be difficult to achieve at present Swedish biogas sales prices. (c) 2014 Elsevier Ltd. All rights reserved.
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27. |
- Gustavsson, Carl Gunnar, et al.
(författare)
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Thrombotic occlusion of all left coronary branches in a young woman with severe ulcerative colitis
- 2011
-
Ingår i: ISRN Cardiology. - : Hindawi Limited. - 2090-5580 .- 2090-5599.
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Tidskriftsartikel (refereegranskat)abstract
- Background. The thrombosis risk is increased in active ulcerative colitis. The limited number of reported complications have predominantly been cerebrovascular but other vessel territories may also be affected. Patient. During a severe attack of ulcerative colitis a 37-year-old woman suffered occlusion of all left coronary artery branches. Serial angiographies showed progressive recanalisation of the coronary arteries during anticoagulation, but no atherosclerotic stenosis. The cause of infarction was thus considered to be an extensive coronary thrombosis. However, a large battery of blood tests failed to identify any procoagulant abnormality. Conclusion. Evidence is now accumulating that the increased thrombosis risk also may involve the coronary arteries, even in young patients. To the best of our knowledge this is the third reported case ofmyocardial infarction despite angiographically normal coronary arteries in a patient with active ulcerative colitis. The extent of affected myocardiumwas in this case exceptionally large.
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28. |
- Gustavsson, Karl-Erik, et al.
(författare)
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Different types of organic pop-up fertilizers in carrot cultivation: Effects on the concentrations of polyacetylenes and sugars
- 2018
-
Ingår i: Scientia Horticulturae. - : Elsevier BV. - 0304-4238 .- 1879-1018. ; 230, s. 126-133
-
Tidskriftsartikel (refereegranskat)abstract
- The effects on the concentration of falcarinol-type of polyacetylenes and sugars at harvest and after storage of carrots after application of different types (powder, digestate, two micro-granular) of organic pop-up fertilizer, where the fertilizer was placed in small amounts together with the seeds, were studied. Both groups of investigated compounds reflect important sensory attributes of the carrots, while polyacetylenes are considered as potentially health-promoting compounds. Results showed that the type of pop-up organic fertilizer as well as the dose can affect the concentrations of polyacetylenes and sugars. The dose of nitrogen applied did not seem to alone affect the concentration of polyacetylenes in carrots, while low amounts of applied phosphorus could be related to higher amounts of falcarindiol. The liquid digestate resulted in the highest concentrations of poly acetylenes in two of the treatments, even though the applied doses of digestate contained among the lowest amounts of nutrients. Storage resulted in both increases and decreases of total polyacetylenes, falcarindiol and falcarinol, while falcarindiol-3-acetate generally increased during storage. The sugars showed less variation due to the type or dose of fertilizer applied, as compared with the polyacetylenes.
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29. |
- Gärdenäs, Annemieki, et al.
(författare)
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Estimating soil carbon stock changes by process-based models and soil inventories : uncertainties and complementarities
- 2011
-
Ingår i: Soil Carbon in Sensitive European Ecosystems. - Oxford : Wiley-Blackwell. - 9781119970019
-
Bokkapitel (refereegranskat)abstract
- In this chapter, four examples of scientific questions and challenges in which process-oriented modelling could provide a useful contribution for accounting soil organic carbon (SOC) stocks and changes are presented. These challenges include cases i) when measurements are either time-consuming and/or expensive or there are methodological limitations; ii) an attempt to verify the national soil inventory estimates through comparison with process-based model estimates; iii) prediction of the potential impact on SOC changes due to land-use change; and iv) a comparison of different scenarios for mitigating GHG-emissions. We found that the use of process-based models offers a complementary way to account SOC change and provides an option for assessing the potential impact of climate and land-use change on SOC stocks. However, uncertainty in model estimates is inherent and needs to be communicated. Progress has been made in the assessment of uncertainty and there is growing awareness of how this uncertainty can be communicated. Suggestions for collaborative approaches are presented in order to reduce the uncertainties.
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30. |
- Hansson, Malin, 1967, et al.
(författare)
-
CCL28 is increased in human Helicobacter pylori induced gastritis and mediates recruitment of gastric IgA-secreting cells.
- 2008
-
Ingår i: Infection and Immunity. - 0019-9567. ; 76:7, s. 3304-11
-
Tidskriftsartikel (refereegranskat)abstract
- Human Helicobacter pylori infection gives rise to an active chronic gastritis and is a major risk factor for the development of duodenal ulcer disease and gastric adenocarcinoma. The infection is accompanied by a large accumulation of immunoglobulin A (IgA)-secreting cells in the gastric mucosa, and following mucosal immunization only H. pylori-infected volunteers mounted a B-cell response in the gastric mucosa. To identify the signals for recruitment of gastric IgA-secreting cells, we investigated the gastric production of CCL28 (mucosa-associated epithelial chemokine) and CCL25 (thymus-expressed chemokine) in H. pylori-infected and uninfected individuals and the potential of gastric B-cell populations to migrate toward these chemokines. Gastric tissue from H. pylori-infected individuals contained significantly more CCL28 protein and mRNA than that from uninfected individuals, while CCL25 levels remained unchanged. Chemokine-induced migration of gastric lamina propria lymphocytes isolated from patients undergoing gastric resection was then assessed using the Transwell system. IgA-secreting cells and IgA+ memory B cells from H. pylori-infected tissues migrated toward CCL28 but not CCL25, while the corresponding cells from uninfected patients did not. Furthermore, IgG-secreting cells from H. pylori-infected patients did not migrate to CCL28 but instead to CXCL12 (SDF-1). However, chemokine receptor expression did not correlate to the migratory pattern of the different B-cell populations. These studies are the first to show increased CCL28 production during gastrointestinal infection in humans and provide an explanation for the large influx of IgA-secreting cells to the gastric mucosa in H. pylori-infected individuals.
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31. |
- Heiden, Marina, 1974-, et al.
(författare)
-
Mismatch between actual and preferred extent of telework: cross-sectional and prospective associations with well-being and burnout
- 2023
-
Ingår i: BMC Public Health. - : Springer. - 1471-2458. ; 23
-
Tidskriftsartikel (refereegranskat)abstract
- Background: This study aimed to determine whether telework mismatch, i.e., lack of fit between actual and preferred extent of telework, is cross-sectionally and prospectively associated with well-being and burnout.Methods: A questionnaire was sent to employees in a Swedish manufacturing company in November 2020 (baseline) and September 2021 (follow-up). It contained questions about well-being (WHO-5 Well-Being Index) and burnout (Copenhagen Psychosocial Questionnaire III), as well as the preferred extent of telework and extent of telework performed. Telework mismatch was calculated as the difference between the actual and preferred extent of telework. Change in mismatch over time was categorized as 1) less mismatch at follow-up than at baseline, 2) more mismatch at follow-up, and 3) identical levels of mismatch at baseline and follow-up. Multivariate and univariate analyses of variance were used to determine the effects of mismatch and change in mismatch over time on baseline ratings and changes in ratings of well-being and burnout. All analyses were performed with and without adjustment for age, sex, marital status, children, type of employment, commuting time and extent of telework performed.Results: The response rate was 39% at baseline (n=928, 67% men, mean(SD) age: 45(11) years) and 60% at follow-up (n=556, 64% men, mean(SD) age: 46(11) years). A cross-sectional association was found between telework mismatch and well-being, showing that employees who teleworked more than they would like reported worse well-being than those who teleworked less than they would like. No statistically significant association was found between telework mismatch and burnout. The ability of telework mismatch at baseline to predict changes in well-being or burnout over 10 months was small and non-significant. No association was found between change in telework mismatch over the 10-month period and corresponding changes in well-being or burnout.Conclusion: Our results suggest that telework should be thoughtfully practiced in companies/organizations to avoid negative consequences for employees who already telework more than they prefer. Studies are needed to determine how long-term changes in match between preferred and actual extent of telework is associated with employee well-being, including how the association is modified by the nature of the job and the work environment.
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32. |
- Hellenbrand, Markus, et al.
(författare)
-
Capacitance Measurements in Vertical III-V Nanowire TFETs
- 2018
-
Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 39:7, s. 943-946
-
Tidskriftsartikel (refereegranskat)abstract
- By measuring scattering parameters over a wide range of bias points, we study the intrinsic gate capacitance as well as the charge partitioning of vertical nanowire tunnel field-effect transistors (TFETs). The gate-to-drain capacitance Cgd is found to largely dominate the on-state of TFETs, whereas the gate-to-source capacitance Cgs is sufficiently small to be completely dominated by parasitic components. This indicates that the tunnel junction on the source side almost completely decouples the channel charge from the small-signal variation in the source, while the absence of a tunnel junction on the drain side allows the channel charge to follow the drain small-signal variation much more directly.
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33. |
- Hellenbrand, Markus, et al.
(författare)
-
Comparison of Low-Frequency Noise in Nanowire and Planar III-V MOSFETs
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We compare III-V nanowire (NW) metal-oxidesemiconductor field-effect transistors (MOSFETs) in a vertical gate-all-around (GAA) as well as a lateral trigate architecture with planar reference MOSFETs and reveal that the NW geometry does not deteriorate the low-frequency noise (LFN) performance. In fact, with gate oxides deposited at the same conditions, the NW structures show potential to achieve better metrics due to slightly lower border trap densities Nbt. The normalized LFN in transistors with a higher number of NW can degrade due to averaging effects between individual nanowires within the same device.
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34. |
- Hellenbrand, Markus, et al.
(författare)
-
Effect of Gate Oxide Defects on Tunnel Transistor RF Performance
- 2018
-
Ingår i: 2018 76th Device Research Conference (DRC). - 9781538630280 ; , s. 137-138
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Tunnel field-effect transistors (TFETs) are designed for low off-state leakage and low drive voltages. To investigate how capable TFETs are of RF operation, we measured their scattering parameters and performed small-signal modeling. We find that in the low frequency ranges, gate oxide defects have a major influence on the RF performance of these devices, which can be modeled by a frequency-dependent gate-to-drain conductance ggd;w. This model is based on charge trapping in gate oxide defects and was studied before for metal-oxide-semiconductor capacitors.
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35. |
- Hellenbrand, Markus, et al.
(författare)
-
Low-Frequency Noise in Nanowire and Planar III-V MOSFETs
- 2019
-
Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317.
-
Tidskriftsartikel (refereegranskat)abstract
- Nanowire geometries are leading contenders for future low-power transistor design. In this study, low-frequency noise is measured and evaluated in highly scaled III-V nanowire metal-oxide-semiconductor field-effect transistors (MOSFETs) and in planar III-V MOSFETs to investigate to what extent the device geometry affects the noise performance. Number fluctuations are identified as the dominant noise mechanism in both architectures. In order to perform a thorough comparison of the two architectures, a discussion of the underlying noise model is included. We find that the noise performance of the MOSFETs in a nanowire architecture is at least comparable to the planar devices. The input-referred voltage noise in the nanowire devices is superior by at least a factor of four.
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36. |
- Hellenbrand, Markus, et al.
(författare)
-
Random telegraph signal noise in tunneling field-effect transistors with S below 60 mV/decade
- 2017
-
Ingår i: 47th European Solid-State Device Research Conference (ESSDERC), 2017. - 9781509059799 - 9781509059782 ; , s. 38-41
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Single gate oxide defects in strongly scaled Tunneling Field-Effect Transistors with an inverse subthreshold slope well below 60 mV/decade are investigated by Random Telegraph Signal (RTS) noise measurements. The cause for RTS noise are electrons being captured in and released from individual defects in the gate oxide. Under the assumption that elastic tunneling is the underlying capture and emission mechanism, the measured RTS time constants vary with the relative position of the channel Fermi level and the defect energy level while the amplitudes — independent of the capture and release mechanism — follow the inverse of the inverse subthreshold slope.
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37. |
- Herstad-Svärd, S., et al.
(författare)
-
Ramprogram – Åtgärder för samtidig minimering av alkalirelaterade driftproblem, Etapp 2
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of an increasing amount of biofuel and waste woods has resulted in certainenvironmental advantages, including decreased emissions of fossil CO2, SO2 andmetals. On the other hand, a number of chloride and alkali related operational problemshave occurred which are related to combustion of these fuels.Alkali related operational problems have been studied in a project consisting of twoparts. The overall scope has been to characterise the operational problems and to studymeasures to minimise them. The first part was reported in Värmeforsk report 997 wherethe results were summarised in a table of different measures. In part two, additionalmeasures have been included in the test plan and initial corrosion has been studiedlinked to the different measures. The tests have also in part two been carried out at the12 MW CFB boiler at Chalmers. The effect of the selected measures has beeninvestigated concerning both deposit formation and bed agglomeration, and at the sametime emissions and other operational conditions were characterised.The second part of the project has among other things focused on:• To investigate measures which decrease the content of alkali and chloride in thedeposits, and consequently decrease the risk for corrosion (by investigating theinitial corrosion). Focus was also on trying to explain favourable effects.• To investigate if it is possible to combine a rather low dosage of kaolin and injectionof ammonium sulphate. This was done in order to reduce both bed agglomerationand problems from deposits during combustion of fuels rich in chlorine.• To investigate if co-combustion with sewage sludge, de-inking sludge or peat withhigh ash content, could give similar advantages as conventional additives.• Investigate if ash from PFBC is possible to use as an alternative bed material.By comparing the different measures in part two, it could be concluded that cocombustionof sewage sludge gave the best overall effect. The judgement was based onthe effects concerning bed agglomeration, level of alkali chloride in the flue gas,deposits and initial corrosion. Simultaneous addition of kaolin and ammonia sulphatealso had a favourable impact both in the bed and on the alkali chlorides in the gas phase.Dosage of kaolin did not reduce the effect of injected ammonium sulphate. Cocombustionof peat could also be a very attractive alternative, but it is critical to select asuitable peat type. It is of special concern to avoid peat with a high content of calcium,since it can increase the level of alkali chlorides by reacting with available sulphur.Change of bed material to ash from PFBC can decrease problems with bedagglomeration, but there is a risk of increased deposit formation and corrosion. A boileroperated with high steam data should consequently combine the change of bed materialwith injection of ammonium sulphate or another source of sulphur.Co-combustion of de-inking sludge from pulp and paper production can reduceproblems with bed agglomeration. There is, however, an increased chance of corrosiondue to the high content of calcium. Injection of sulphates may improve the situationconcerning corrosion. The results also showed that low potassium chlorine content in the flue gas decreasesthe risk of corrosion. Increased amount of potassium chlorine content in the flue gaswill not necessary give a high amount of chlorine content in the deposits if there is sulphur in the system.Key words: agglomeration, deposits, corrosion, alkali, kaolin, ammonium sulphate,sludge
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38. |
- Jakobsson, Erik, 1960-
(författare)
-
Mot en ny vuxenutbildningspolitik? : Regional utveckling som policy och praktik
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Avhandlingen beskriver och analyserar ett regionalt utvecklingsinitiativ i nätverksform, genom vilket de kommunala lärcentrumen i Örebro län samverkar för att utveckla en gemensam infrastruktur för vuxnas lärande. Detta innebär, exempelvis, att utveckla former för samverkan mellan olika regionala aktörer inom området, öka samordningen och samverkan inom den kommunala vuxenutbildningen och utveckla metoder för lärande med fokus på arbetet och arbetsplatsen.Den övergripande forskningsfrågan kan formuleras på följande sätt: Vilka är förutsättningarna för att genom regional samverkan, med en horisontell organisering i nätverksform, utveckla politiken, planeringen och organiseringen för vuxnas lärande, och med vilka teoretiska och metodologiska perspektiv kan vi förstå såväl problem som möjligheter?Två övergripande teoretiska perspektiv presenteras i avhandlingen, som relateras till det studerade fallet. Det gäller å ena sidan ett traditionellt planeringsperspektiv och å andra sidan ett evolutionärt lärandeperspektiv. Dessa perspektiv utgör både kontraster och komplement till varandra. Planeringsperspektivet har ’policysändaren’ som utgångspunkt, medan lärandeperspektivet har ’policymottagaren’ som utgångspunkt. Diskussionen i avhandlingen behandlar också de möjligheter som finns att kombinera de båda övergripande perspektiven, både som analytiska och strategiska perspektiv.Sammantaget kan studien av nätverket beskrivas som en kvalitativt inriktad fallstudie, där mitt kontinuerliga deltagande över tid i nätverkets sammankomster är ett centralt inslag. Intervjuer, en enkätundersökning, diskussioner och dokumentstudier utgör också material till studien. En interaktiv forskningsansats har tillämpats, som syftar till en gemensam kunskapsbildning och lärprocess mellan deltagarna och forskaren. Metodologiskt hämtar studien inspiration från den vetenskapsfilosofiska inriktning som kallas kritisk realism.En hastig överblick över studiens resultat ger vid handen att mycket av det som diskuterats i nätverket har stannat vid intentioner och har inte blivit omsatt i en praktik. Nätverket har också förblivit ganska internt, med en krets av lärcentrum- och vuxenutbildningschefer. Lite tillspetsat kan man säga att nätverket varken arbetat sig ’nedåt’ i respektive lokal organisation eller ’uppåt’ mot den politiska sfären, eller ’utåt’ mot det omgivande samhället och arbetslivet.Nätverket har onekligen ändå skapat nya och bättre förutsättningar för samarbete mellan lärcentrumen. Det finns nu betydligt mer av en gemensam förståelse och någonting att bygga vidare på, regionalt och lokalt. Det är också hoppfullt att se att nätverket fortsätter sitt arbete trots att det inte längre har externt stöd. Nätverket har, förefaller det, etablerat sig som en gemensam utvecklingsorganisation för deltagarna, och har nått ett stadium där mer konkreta och påtagliga former av samverkan börjar äga rum.
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39. |
- Johansson, Christina, et al.
(författare)
-
Växtnäring från trekammarbrunnar för hållbar produktion av energigräs : rapportering för åren 2007 och 2008
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det långsiktiga målet för projekt ”Växtnäring från trekammarbrunnar för hållbar produktion av energigräs” är att visa på hållbara metoder för produktion av fleråriga energigräs på energiåkrar som gödslas med trekammarbrunnsslam. Uppnås projektets långsiktiga mål innebär det en mer hållbar odling av energigräs för produktion av fordonsbränsle (biogas och bioetanol) eller fastbränsle. I större skala innebär det en ökad återföring av växtnäring från samhället till jordbruket, via trekammarbrunnsslam från landsbygden. Det innebär en minskad användning av fossil energi genom minskade transporter av trekammarbrunnsslam till reningsverk, minskat behov av konstgödsel vid odling av energigräsen och genom att energigräsen kan ersätta fossil energi. Växtnäringen i trekammarbrunnsslammet uppgraderas via odling och användning av energigräsen som biogassubstrat alt. som fastbränsle när de växtnäringsrika restprodukterna (biogödsel eller aska) blir så rena att de kan användas som gödselmedel vid livsmedels- och foderproduktion. Se rapportens framsida som schematiskt visar hur trekammarbrunnsslam kan ingå i ett kretslopp. Det kortsiktiga målet för projektet är att utvärdera möjligheterna att nyttiggöra trekammarbrunnsslam som en växtnäringsresurs vid odling av fleråriga energigräs såsom rörflen och biogasvall på energiåkrar i jämförelse med ett nytt högavkastande energigräs Szarvasi-1. Detta sker genom odlingsförsök med energigräsen, analyser och värdering av dessa för olika energiändamål, hygieniska studier på trekammarbrunnsslammet samt kemiska analyser av åkermarken och av trekammarbrunnsslammet som används i odlingsförsöken. I denna rapport redovisas resultat från 1)Etablering av energigräsen i odlingsförsök 2)Utvärdering av trekammarbrunnsslammet som en växtnäringsresurs 3)Utvärdering av hygienisering av trekammarbrunnsslammet med tillsats av urea 4)Studier av produktion av bioetanol och biogas baserad på energigräs. Trekammarbrunnsslammet har en betydligt sämre kvalitet ur växtnärings- och metallsynpunkt än både nötflytgödsel och klosettvatten från slutna avloppstankar. Koppar- och zinkhalterna i trekammarbrunnsslam kan överskrida gränsvärdena enligt reglerna för spridning av avloppsslam på åkermark. Hygienisering med 0,6 % urea i 3 månader visade sig ge en acceptabel hygienisk kvalitet för användning av trekammarbrunnsslam i energiodling. Halterna av miljöstörande organiska ämnen ligger långt under riktvärdena för avloppsslam. Kombinerad produktion av etanol och biogas från ångbehandlad hampa gav i labskala 20-25% högre bruttoproduktion av drivmedel jämfört med att endast göra biogas från finhackad hampa. Det som återstår att studera är: a)Hygieniseringens effektivitet på indikatororganismerna vid olika doser av urea b)Hygieniska gränsvärden vid spridning av trekammarbrunnsslam i växande energigröda c)Energigräsens potential för produktion av bioetanol och biogas vid olika skördetidpunkter d)Energigräsens potential som stråbränsle vid olika skördetidpunkter e)Gödslingseffektiviteten och energibalansen vid olika användningar av energigräsen f)Eventuell ackumulation av metaller och organiska föroreningar i energiåkern. The long-term objective of the project ‘Plant nutrients from three-chamber septic tanks in sustainable production of energy grass’ is to demonstrate sustainable methods for the production of perennial grass leys on arable land dedicated to energy crops fertilised with sewage sludge from three-chamber septic tanks. Achievement of this long-term objective will allow more sustainable production of energy grass for use as vehicle fuel (biogas and bioethanol) or solid fuel. On a larger scale it will increase recycling of plant nutrients from society to agriculture via three-chamber septic tank sludge from rural homes. That will decrease the use of fossil energy indirectly by decreasing the need for mineral fertilisers and for sludge transport to sewage plants, and directly through biofuel made from the energy grass replacing fossil energy. The plant nutrients in the sludge are upgraded through the cultivation of energy grass and its use as a biogas substrate or solid fuel, since the nutrient-rich residues (biodigestate or ash) are so well-sanitised that they can be used as a fertiliser in food and feed production. The diagram on the front cover shows how three-chamber septic tank sludge can be incorporated into nutrient recycling. The short-term objective of the project was to assess the potential for utilising three-chamber septic tank sludge as a plant nutrient resource in the cultivation of perennial energy grasses such as reed canarygrass and biogas leys on arable land dedicated to energy crops, in comparison with the high-yielding energy grass Szarvasi-1. This was achieved through cropping trials with the energy grasses, analyses and evaluations of these for different energy purposes, hygiene studies on the three-chamber septic tank sludge and chemical analyses of the soil and the sludge used in the cropping trials. This report presents results on: 1)Establishment of energy grass in cropping trials. 2)Evaluation of three-chamber septic tank sludge as a plant fertiiser. 3)Evaluation of sludge sanitation through the addition of urea. 4)Preliminary studies of bioethanol and biogas production based on energy grass The three-chamber septic tank sludge is of much lower quality from a nutrient and metal perspective than cattle manure or blackwater from holding tanks. The copper and zinc concentrations in the sludge can exceed the permissible values for spreading sewage sludge on arable land. Sanitation with 0.6% urea for three months was shown to give acceptable hygiene quality for use of the three-chamber septic tank sludge in energy crops. The concentrations of organic environmental pollutants were well below the permissible values for sewage sludge. The next phase of the project will examine: a)The efficacy of sanitation at different doses of urea. b)Permissible hygiene values for spreading three-chamber septic tank sludge in growing energy grass. c)The potential of energy grasses for production of bioethanol and biogas at different harvesting times. d)The potential of energy grasses as a solid fuel at different harvesting times. e)The fertiliser efficiency and energy balance for energy grass. f)The incidence of metal and organic pollutant accumulation in energy grass fields.
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40. |
- Johansson, Christina, et al.
(författare)
-
Växtnäring från trekammarbrunnar till energigräs
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En slutsats som dragits inom projektet är att själva kretsloppet för växtnäringsinnehållet i trekammarbrunnsslam inte är den viktigaste frågan ur hållbarhetssynpunkt vid odling av energigräs, eftersom återföringen av växtnäring med trekammarbrunnsslam, främst fosfor och kalium, är mycket begränsad. I stället är själva nyttjandet av energigräset som råvara för produktion av förnybara drivmedel mycket viktigare ur hållbarhetssynpunkt. Hållbarheten i systemet ligger i att energigräset kan omvandlas till förnybara drivmedel, såsom biogas och bioetanol, vilka ersätter bensin och diesel, som har en mycket stor klimatpåverkan. Enligt litteraturuppgifter ger en vallgröda på ca 9 ton torrsubstans (ts) per ha och år, en reduktion av växthusgasemissioner med ca 6 ton CO2-ekv. per hektar och år, under förutsättning att fordonsgas i form av metan produceras av vallgrödan och biogödseln, som kvarstår efter rötningen av vallgrödan, ersätter mineralgödsel på produktiv åkermark. Inom projektet har vi uppnått skördar på 5 - 15 ton ts per ha och år beroende på odlingslokal och vilket energigräs som odlats, om gräset varit gödslat eller ogödslat samt om baljväxter ingått i ”biogasvallen”. Skördenivåer i detta intervall tyder på att man kan uppnå ett hållbart system för produktion av biogas baserat på energigräs, enligt EU:s nuvarande hållbarhetskriterier (en CO2-reduktion på minst 35 %) för förnybara drivmedel, oberoende om gräset gödslas med trekammarbrunnsslam eller ej. Särskilt stor klimatnytta uppnås vid användning av biogasvallar som innehåller både gräs och baljväxter, eftersom dessa ger hög biomassaavkastning helt utan kvävegödsling. Biogaspotentialen hos de energigräs och biogasvallar som studerats i projektet ligger normalt i intervallet 250 – 350 l CH4 per kg VS, beroende på skördetidpunkt och förbehandlingsmetod. Att använda energiåkrar för odling av fleråriga energigräs där biomassan används för produktion av biogas, bioetanol eller fastbränsle innebär flera miljövinster, mest påtagligt genom minskad klimatpåverkan, eftersom fossil energi ersätts, men även genom att fleråriga grödor har lägre behov av insatser i form av jordbearbetning och ogräsbekämpning och lagrar in mer kol i rötterna och marken än ettåriga grödor. Ytterligare miljövinster kan erhållas om biomassa skördas på ogödslade energiåkrar nära känsliga vattenmiljöer, eftersom man då kan transportera bort växtnäring till produktiv åkermark, som annars skulle kunna orsaka övergödning. Vid användning av energigräs som biogassubstrat kan biogödseln, som blir kvar efter rötningen, användas som ett värdefullt gödselmedel inom ekologisk eller konventionell odling. Biogödseln innehåller lättillgänglig växtnäring och om den används för gödsling av livsmedelsgrödor på åkermark sker en stor miljövinst genom ersättning av mineralgödsel. För att trekammarbrunnsslam skall kunna användas som ett gödselmedel till energigräs så krävs det en hygienisering genom t.ex. tillsats av minst 0,6 % urea och lagring i minst 3 månader. Hygienisering med urea medför dock att trekammarbrunnsslammet får ett relativt högt kväveinnehåll i jämförelse med andra viktiga växtnäringsämnen, såsom fosfor och kalium. Detta innebär att fosfor och kalium måste tillföras med andra gödselmedel för att energiåkern inte skall lida brist på dessa växtnäringsämnen på längre sikt. Tillförseln av tungmetaller med det hygieniserade trekammarbrunnsslammet till energiåkern bedöms vara något större jämfört med om källsorterat klosettvatten eller nötflytgödsel används som gödselmedel till energigräsen. Halterna av miljöstörande organiska ämnena i trekammarbrunnsslam ligger dock långt under riktvärdena för avloppsslam enligt slamöverenskommelsen. Allt detta visar att hygieniserat trekammarbrunnsslam kan användas som en växtnäringsresurs vid odling av energigräs eller biogasvallar på energiåkrar, men att hygieniserat klosettvatten skulle vara ett väl så bra alternativ.
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41. |
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42. |
- Jönsson, Adam, et al.
(författare)
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Doping Profiles in Ultrathin Vertical VLS-Grown InAs Nanowire MOSFETs with High Performance
- 2021
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Ingår i: ACS Applied Electronic Materials. - : American Chemical Society (ACS). - 2637-6113. ; 3:12, s. 5240-5247
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Tidskriftsartikel (refereegranskat)abstract
- Thin vertical nanowires based on III-V compound semiconductors are viable candidates as channel material in metal oxide semiconductor field effect transistors (MOSFETs) due to attractive carrier transport properties. However, for improved performance in terms of current density as well as contact resistance, adequate characterization techniques for resolving doping distribution within thin vertical nanowires are required. We present a novel method of axially probing the doping profile by systematically changing the gate position, at a constant gate length Lg of 50 nm and a channel diameter of 12 nm, along a vertical nanowire MOSFET and utilizing the variations in threshold voltage VT shift (∼100 mV). The method is further validated using the well-established technique of electron holography to verify the presence of the doping profile. Combined, device and material characterizations allow us to in-depth study the origin of the threshold voltage variability typically present for metal organic chemical vapor deposition (MOCVD)-grown III-V nanowire devices.
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43. |
- Jönsson, Adam, et al.
(författare)
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Gate-Length Dependence of Vertical GaSb Nanowire p-MOSFETs on Si
- 2020
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Ingår i: IEEE Transactions on Electron Devices. - 0018-9383. ; 67:10, s. 4118-4122
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Tidskriftsartikel (refereegranskat)abstract
- The effect of gate-length variation on key transistor metrics for vertical nanowire p-type GaSb metal-oxide-semiconductor field-effect transistors (MOSFETs) are demonstrated using a gate-last process. The new fabrication method enables short gate-lengths (Lg = 40 nm) and allows for selective digital etching of the channel region. Extraction of material properties as well as contact resistance are obtained by systematically varying the gate-length. The fabricated transistors show excellent modulation properties with a maximum Ion/Ioff = 700 (VGS = -0.5,,V) as well as peak transconductance of 50 μS/μm with a linear subthreshold swing of 224 mV/dec.
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44. |
- Karlsson, Sofia, 1982, et al.
(författare)
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A Laboratory Study of the in Situ Sulfation of Alkali Chloride Rich Deposits: Corrosion Perspective
- 2016
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 30:9, s. 7256-7267
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Tidskriftsartikel (refereegranskat)abstract
- The initial corrosive effect of small (1.35 mu mol/cm(2)) and large (13.5 mu mol/cm(2)) amounts of KCl on 304L has been investigated. The investigations were performed in both the absence and presence of 300 ppm of SO2 at 600 degrees C. The results showed that in the absence of SO2 KCl accelerates the rate of corrosion by means of two types of corrosion attack: a general attack and a steel grain boundary attack. The general attack has been proved to be initiated by K2CrO4 formation. Meanwhile, the steel grain boundary attack is suggested to be accelerated by HCl released due to the chromate formation which increased with higher amounts of KCl. The presence of KCl and SO2 resulted in the simultaneous formation of K2SO4 and K2CrO4. The chromate formation resulted in a general corrosion attack. However, the oxide growth was significantly reduced due to the very fast sulfation reaction. In contrast, the steel grain boundary attack increased in the presence of SO2. It is suggested that the attack is accelerated by HCl released from the sulfation reaction and by sulfidation of the steel grain boundaries.
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45. |
- Kilpi, Olli Pekka, et al.
(författare)
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Electrical Properties of Vertical InAs/InGaAs Heterostructure MOSFETs
- 2019
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Ingår i: IEEE Journal of the Electron Devices Society. - 2168-6734. ; 7, s. 70-75
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Tidskriftsartikel (refereegranskat)abstract
- Vertical InAs/InGaAs nanowire MOSFETs are fabricated in a gate-last fabrication process, which allows gate-lengths down to 25 nm and accurate gate-alignment. These devices demonstrate high performance with transconductance of 2.4 mS/μm, high on-current, and off-current below 1 nA/μm. An in-depth analysis of the heterostructure MOSFETs are obtained by systematically varying the gate-length and gate location. Further analysis is done by using virtual source modeling. The injection velocities and transistor metrics are correlated with a quasi-ballistic 1-D MOSFET model. Based on our analysis, the observed performance improvements are related to the optimized gate-length, high injection velocity due to asymmetric scattering, and low access resistance.
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46. |
- Kilpi, Olli Pekka, et al.
(författare)
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High-Performance Vertical III-V Nanowire MOSFETs on Si with gm> 3 mS/μm
- 2020
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Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 41:8, s. 1161-1164
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Tidskriftsartikel (refereegranskat)abstract
- Vertical III-V nanowire MOSFETs have demonstrated excellent performance including high transconductance and high Ion. One main bottleneck for the vertical MOSFETs is the large access resistance arising from the contacts and ungated regions. We demonstrate a process to reduce the access resistance by combining a gate-last process with ALD gate-metal deposition. The devices demonstrate fully scalable gm down to Lg = 25 nm. These vertical core/shell InAs/InGaAs MOSFETs demonstrate gm = 3.1 mS/μm and Ron = 190 Ωμm. This is the highest gm demonstrated on Si. Transmission line measurement verifies a low contact resistance with RC = 115 Ωμm, demonstrating that most of the MOSFET access resistance is located in the contact regions.
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47. |
- Kilpi, Olli Pekka, et al.
(författare)
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Increased Breakdown Voltage in Vertical Heterostructure III-V Nanowire MOSFETs with a Field Plate
- 2021
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Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 42:11, s. 1596-1598
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Tidskriftsartikel (refereegranskat)abstract
- Vertical III-V heterostructure MOSFETs exhibit outstanding performance at reduced supply voltages. In this paper, we report on a novel process of extending high-speed device operation towards higher voltages. The device vertical geometry allows for engineering a field plate by covering the nanowire drain area with a 10-nm-thick SiO2 film. The film acts as a field moderator in the device drain region. Reference devices without a field plate exhibit a transconductance of 2.5 mS/μm, while devices with a 120-nm-long field plate show 1.5 mS/μm but a three times increase in breakdown voltage. Measurements show that the field-screening effect attributes to reduced band-to-band tunneling and impact ionization, thereby reducing the parasitic bipolar effect in the MOSFET channel as well. The devices show promise in applications in circuits and systems requiring large power-handling.
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48. |
- Kilpi, Olli Pekka, et al.
(författare)
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Vertical heterojunction InAs/InGaAs nanowire MOSFETs on Si with Ion = 330 μa/μm at Ioff = 100 nA/μm and VD = 0.5 v
- 2017
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Ingår i: 2017 Symposium on VLSI Technology, VLSI Technology 2017. - 9784863486058 ; , s. 36-37
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Konferensbidrag (refereegranskat)abstract
- We present vertical InAs nanowire MOSFETs on Si with an In0.7Ga0.3As drain. The devices show Ion and gm/SS record performance for vertical MOSFETs and Ioff below 1 nA/μm at Vd 0.5 V. We show a device with gm=1.4 mS/μm and SS=85 mV/dec, therefore having Q-value (gm/SS) of 16. The device has Ion=330 μA/μm and 46 μA/μm at Ioff 100 nA/μm and 1 nA/μm, respectively. Furthermore, we show a device with SS=68 mV/dec and Ion=88 μA/μm at Ioff 1 nA/μm and Vd 0.5 V.
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49. |
- Kilpi, Olli Pekka, et al.
(författare)
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Vertical InAs/InGaAs Heterostructure Metal-Oxide-Semiconductor Field-Effect Transistors on Si
- 2017
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 17:10, s. 6006-6010
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Tidskriftsartikel (refereegranskat)abstract
- III-V compound semiconductors offer a path to continue Moore's law due to their excellent electron transport properties. One major challenge, integrating III-V's on Si, can be addressed by using vapor-liquid-solid grown vertical nanowires. InAs is an attractive material due to its superior mobility, although InAs metal-oxide-semiconductor field-effect transistors (MOSFETs) typically suffer from band-to-band tunneling caused by its narrow band gap, which increases the off-current and therefore the power consumption. In this work, we present vertical heterostructure InAs/InGaAs nanowire MOSFETs with low off-currents provided by the wider band gap material on the drain side suppressing band-to-band tunneling. We demonstrate vertical III-V MOSFETs achieving off-current below 1 nA/μm while still maintaining on-performance comparable to InAs MOSFETs; therefore, this approach opens a path to address not only high-performance applications but also Internet-of-Things applications that require low off-state current levels.
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50. |
- Kilpi, Olli-Pekka, et al.
(författare)
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Vertical nanowire III–V MOSFETs with improved high-frequency gain
- 2020
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 56:13, s. 669-671
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Tidskriftsartikel (refereegranskat)abstract
- High-frequency performance of vertical InAs/InGaAs heterostructure nanowire MOSFETs on Si is demonstrated for the first time for a gate-last configuration. The device architecture allows highly asymmetric capacitances, which increases the power gain. A device with Lg = 120 nm demonstrates fT = 120 GHz, fmax = 130 GHz and maximum stable gain (MSG) = 14.4 dB at 20 GHz. These metrics demonstrate the state-of-the-art performance of vertical nanowire MOSFETs.
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