| 1. |
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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Alexander, Stephen P. H., et al.
(författare)
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The Concise Guide to PHARMACOLOGY 2023/24: G protein-coupled receptors
- 2023
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Ingår i: BRITISH JOURNAL OF PHARMACOLOGY. - : British pharmacological society. - 0007-1188 .- 1476-5381. ; 180
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Tidskriftsartikel (refereegranskat)abstract
- The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and about 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at . G protein-coupled receptors are one of the six major pharmacological targets into which the Guide is divided, with the others being: ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.
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| 3. |
- Beaney, Thomas, et al.
(författare)
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May measurement month 2019 : The global blood pressure screening campaign of the international society of hypertension
- 2020
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Ingår i: Hypertension. - 0194-911X. ; 76:2, s. 333-341
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Tidskriftsartikel (refereegranskat)abstract
- Elevated blood pressure remains the single biggest risk factor contributing to the global burden of disease and mortality. May Measurement Month is an annual global screening campaign aiming to improve awareness of blood pressure at the individual and population level. Adults (≥18 years) recruited through opportunistic sampling were screened at sites in 92 countries during May 2019. Ideally, 3 blood pressure readings were measured for each participant, and data on lifestyle factors and comorbidities were collected. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, or a diastolic blood pressure ≥90 mm Hg (mean of the second and third readings) or taking antihypertensive medication. When necessary, multiple imputation was used to estimate participants' mean blood pressure. Mixed-effects models were used to evaluate associations between blood pressure and participant characteristics. Of 1 508 130 screenees 482 273 (32.0%) had never had a blood pressure measurement before and 513 337 (34.0%) had hypertension, of whom 58.7% were aware, and 54.7% were on antihypertensive medication. Of those on medication, 57.8% were controlled to <140/90 mm Hg, and 28.9% to <130/80 mm Hg. Of all those with hypertension, 31.7% were controlled to <140/90 mm Hg, and 350 825 (23.3%) participants had untreated or inadequately treated hypertension. Of those taking antihypertensive medication, half were taking only a single drug, and 25% reported using aspirin inappropriately. This survey is the largest ever synchronized and standardized contemporary compilation of global blood pressure data. This campaign is needed as a temporary substitute for systematic blood pressure screening in many countries worldwide.
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| 4. |
- Christopoulos, Arthur, et al.
(författare)
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THE CONCISE GUIDE TO PHARMACOLOGY 2021/22: G protein-coupled receptors.
- 2021
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Ingår i: British journal of pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 178 Suppl 1
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Forskningsöversikt (refereegranskat)abstract
- The Concise Guide to PHARMACOLOGY 2021/22 is the fifth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of nearly 1900 human drug targets with an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes over 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/bph.15538. G protein-coupled receptors are one of the six major pharmacological targets into which the Guide is divided, with the others being: ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2021, and supersedes data presented in the 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.
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| 5. |
- Kaschina, Elena, et al.
(författare)
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Angiotensin II type 2 receptor stimulation : a novel option of therapeutic interference with the renin-angiotensin system in myocardial infarction?
- 2008
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Ingår i: Circulation. - 0009-7322 .- 1524-4539. ; 118:24, s. 2523-32
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: This study is the first to examine the effect of direct angiotensin II type 2 (AT(2)) receptor stimulation on postinfarct cardiac function with the use of the novel nonpeptide AT(2) receptor agonist compound 21 (C21). METHODS AND RESULTS: Myocardial infarction (MI) was induced in Wistar rats by permanent ligation of the left coronary artery. Treatment with C21 (0.01, 0.03, 0.3 mg/kg per day IP) was started 24 hours after MI and was continued until euthanasia (7 days after MI). Infarct size was assessed by magnetic resonance imaging, and hemodynamic measurements were performed via transthoracic Doppler echocardiography and intracardiac Millar catheter. Cardiac tissues were analyzed for inflammation and apoptosis markers with immunoblotting and real-time reverse transcription polymerase chain reaction. C21 significantly improved systolic and diastolic ventricular function. Scar size was smallest in the C21-treated rats. In regard to underlying mechanisms, C21 diminished MI-induced Fas-ligand and caspase-3 expression in the peri-infarct zone, indicating an antiapoptotic effect. Phosphorylation of the p44/42 and p38 mitogen-activated protein kinases, both involved in the regulation of cell survival, was strongly reduced after MI but almost completely rescued by C21 treatment. Furthermore, C21 decreased MI-induced serum monocyte chemoattractant protein-1 and myeloperoxidase as well as cardiac interleukin-6, interleukin-1beta, and interleukin-2 expression, suggesting an antiinflammatory effect. CONCLUSIONS: Direct AT(2) receptor stimulation may be a novel therapeutic approach to improve post-MI systolic and diastolic function by antiapoptotic and antiinflammatory mechanisms.
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| 6. |
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| 7. |
- Poulter, Neil R., et al.
(författare)
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May Measurement Month : results of 12 national blood pressure screening programmes between 2017 and 2019
- 2022
-
Ingår i: European Heart Journal, Supplement. - : Oxford University Press (OUP). - 1520-765X .- 1554-2815. ; 24:Sf, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- The frst May Measurement Month (MMM) campaign, a global blood pressure (BP) screening programme, began in 2017 as an initiative of the International Society of Hypertension.1 Two subsequent annual campaigns have also been completed in consecutive years2,3 and having had to defer activities due to the COVID-19 pandemic in 2020 the fourth campaign was run in 2021, the results of which are currently in press. Since its initiation in 2017, volunteers from more than 100 countries have participated. The aims of MMM have remained consistent from the start-to raise awareness of the importance of the measurement of BP at the individual and population level and to provide a temporary pragmatic solution to the shortfall in BP screening programmes in countries around the world.
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| 8. |
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| 9. |
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| 10. |
- Almora, Osbel, et al.
(författare)
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Device Performance of Emerging Photovoltaic Materials (Version 1)
- 2020
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Emerging photovoltaics (PVs) focus on a variety of applications complementing large scale electricity generation. Organic, dye-sensitized, and some perovskite solar cells are considered in building integration, greenhouses, wearable, and indoor applications, thereby motivating research on flexible, transparent, semitransparent, and multi-junction PVs. Nevertheless, it can be very time consuming to find or develop an up-to-date overview of the state-of-the-art performance for these systems and applications. Two important resources for recording research cells efficiencies are the National Renewable Energy Laboratory chart and the efficiency tables compiled biannually by Martin Green and colleagues. Both publications provide an effective coverage over the established technologies, bridging research and industry. An alternative approach is proposed here summarizing the best reports in the diverse research subjects for emerging PVs. Best performance parameters are provided as a function of the photovoltaic bandgap energy for each technology and application, and are put into perspective using, e.g., the Shockley–Queisser limit. In all cases, the reported data correspond to published and/or properly described certified results, with enough details provided for prospective data reproduction. Additionally, the stability test energy yield is included as an analysis parameter among state-of-the-art emerging PVs.
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| 11. |
- Bader, Thomas K., 1980-, et al.
(författare)
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Combined ultrasonic-mechanical characterization of orthotropic elastic properties of an unrefined bagasse fiber-polypropylene composite
- 2016
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Ingår i: Composites Part B. - : Elsevier BV. - 1359-8368 .- 1879-1069. ; 95, s. 96-104
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Tidskriftsartikel (refereegranskat)abstract
- Use of wood-fiber plastics for construction purposes calls for comprehensive understanding of their anisotropic mechanical properties. As a respective contribution, we here report the first-ever complete elasticity characterization of an orthotropic bagasse fiber polypropylene composite, requiring identification of nine independent constants. For this purpose, we carry out characterization in principal material directions. Six diagonal stiffness tensor components are quantified based on ultrasonic longitudinal and shear wave velocity measurements; and three diagonal compliance tensor components are identified as the inverses of three Young’s moduli derived from unloading regimes of quasi-static uniaxial compression tests. Combination of all measurement data in the framework of orthotropic linear elasticity provides access to all off-diagonal stiffness and compliance tensor components, opening the door to quantifying six Poisson’s ratios.
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| 12. |
- Dagar, Janardan, et al.
(författare)
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Alkali Salts as Interface Modifiers in n-i-p Hybrid Perovskite Solar Cells
- 2019
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Ingår i: Solar RRL. - : Wiley. - 2367-198X. ; 3:9
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Tidskriftsartikel (refereegranskat)abstract
- After demonstration of a 23% power conversion efficiency, a high operational stability is the next most important scientific and technological challenge in perovskite solar cells (PSCs). A potential failure mechanism is tied to a bias-induced ion migration, which causes current–voltage hysteresis and a decay in the device performance over time. Herein, alkali salts are shown to mitigate hysteresis and stabilize device performance in n-i-p hybrid planar PSCs. Different alkali salts of potassium chloride, iodide, and nitrate as well as sodium chloride and iodide are deposited from aqueous solution onto the n-type contact, based on SnO2, prior to deposition of the perovskite absorber Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3. Introduction of potassium-based alkali salts suppresses the current–voltage hysteresis and stabilizes the operational device stability at the maximum power point. This is attributed to the suppression of hole trapping at the n-type selective transport layer (SnO2)/perovskite interface observed by surface photovoltage spectroscopy, which is interpreted to reduce interfacial recombination and improve charge carrier extraction. The best and most stable performance of 19% is achieved using potassium nitrate as the interface modifier. Devices with higher and more stable performance exhibit substantially lower current transients, analyzed during maximum power point tracking.
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| 13. |
- Dagar, Janardan, et al.
(författare)
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Compositional and Interfacial Engineering Yield High-Performance and Stable p-i-n Perovskite Solar Cells and Mini-Modules
- 2021
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Ingår i: ACS applied materials & interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:11, s. 13022-13033
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Tidskriftsartikel (refereegranskat)abstract
- Through the optimization of the perovskite precursor composition and interfaces to selective contacts, we achieved a p-i-n-type perovskite solar cell (PSC) with a 22.3% power conversion efficiency (PCE). This is a new performance record for a PSC with an absorber bandgap of 1.63 eV. We demonstrate that the high device performance originates from a synergy between (1) an improved perovskite absorber quality when introducing formamidinium chloride (FACl) as an additive in the "triple cation" Cs0.05FA0.79MA0.16PbBr0.51I2.49 (Cs-MAFA) perovskite precursor ink, (2) an increased open-circuit voltage, VOC, due to reduced recombination losses when using a lithium fluoride (LiF) interfacial buffer layer, and (3) high-quality hole-selective contacts with a self-assembled monolayer (SAM) of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) on ITO electrodes. While all devices exhibit a high performance after fabrication, as determined from current-density voltage, J-V, measurements, substantial differences in device performance become apparent when considering longer-term stability data. A reduced long-term stability of devices with the introduction of a LiF interlayer is compensated for by using FACl as an additive in the metal-halide perovskite thin-film deposition. Optimized devices maintained about 80% of the initial average PCE during maximum power point (MPP) tracking for >700 h. We scaled the optimized device architecture to larger areas and achieved fully laser patterned series-interconnected mini-modules with a PCE of 19.4% for a 2.2 cm2 active area. A robust device architecture and reproducible deposition methods are fundamental for high performance and stable large-area single junction and tandem modules based on PSCs.
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| 14. |
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| 15. |
- Göransson, Lisa, 1982, et al.
(författare)
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Linkages between demand-side management and congestion in the European electricity transmission system
- 2014
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 69, s. 860-872
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate the possibility to reduce congestion in the transmission grid through large-scale implementation of demand-side management (DSM) in the form of load shifting for the EU-27 countries, Norway, and Switzerland for Year 2020. A linear, cost-minimising, dispatch model that includes a DC load-flow description of the transmission system and a general representation of load shifting is used. It is assumed that the EU Member States fulfil the targets for Year 2020 in their national renewable energy action plans. In the model calculations, a reference case without load shifting is compared with cases in which the load shifting is 5%, 10%, 15% or 20% of the load. The possibility to shift load in time is added exogenously and economic incentives for DSM are not evaluated. Three types of congestion are identified: peak-load-hour congestion, low-load-hour congestion and all-hour congestion. Peak-load-hour congestion is reduced as the DSM share of the load increases, whereas low-load-hour congestion, which is typically associated with a high level of wind generation, persists at all the DSM penetration levels investigated. We show that all-hour congestion occurs between systems that have large differences in supply structure, and that the impact of DSM on all-hour congestion is low. (C) 2014 Elsevier Ltd. All rights reserved.
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| 16. |
- Hellmark, Thomas, et al.
(författare)
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Identification of a clinically relevant immunodominant region of collagen IV in Goodpasture disease
- 1999
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Ingår i: Kidney International. - : Elsevier BV. - 1523-1755 .- 0085-2538. ; 55:3, s. 936-944
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The characteristic feature of Goodpasture disease is the occurrence of an autoantibody response to the noncollagenous domain of the alpha3 chain of type IV collagen [alpha3(IV)NC1] in the alveolar and glomerular basement membrane. These antibodies are associated with the development of a rapidly progressive glomerulonephritis, with or without lung hemorrhage, whereas autoantibodies specific for the other alpha chains of the heterotrimeric type IV collagen probably do not cause disease. In this study, we have investigated whether differences in fine specificity of autoimmune recognition of the alpha3(IV)NC1 correlate with clinical outcome. METHODS: For mapping of antibody binding to type IV collagen, chimeric collagen constructs were generated in which parts of the alpha3(IV)NC1 domain were replaced by the corresponding sequences of homologous nonreactive alpha1(IV). The different recombinant collagen chimeras allowed the analysis of antibody specificities in 77 sera from well-documented patients. RESULTS: One construct that harbors the aminoterminal third of the alpha3(IV)NC1 was recognized by all sera, indicating that it represents the dominant target of the B-cell response in Goodpasture disease. Seventy percent of the samples recognized other parts of the molecule as well. However, only reactivity to the N-terminus of the alpha3(IV)NC1 correlated with prognosis, that is, kidney survival after six months of follow-up. CONCLUSION: The results indicate the crucial importance of antibody recognition of this particular domain for the pathogenesis of Goodpasture disease, thereby opening new avenues for the development of better diagnostic and therapeutic procedures.
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| 17. |
- Johnsson, Filip, 1960, et al.
(författare)
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Delrapport B1. Nyckelverksamheter i omställningen - Till Klimaträttsutredningen M 2019:05
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vårt uppdrag från Klimaträttsutredningen har bestått i att svara på om, samt på vilka grunder, man kan peka ut fysiska verksamheter som bedöms kunna vara avgörande för att målet om nettonollutsläpp ska kunna nås i Sverige. Det övergripande syftet med detta är att i så fall, i en tillståndsprövning, kunna ha möjligheten att låta dessa verksamheters potentiella klimatnytta i vissa fall väga tyngre än lokal miljöpåverkan eller andra samhällsmål. Som vi resonerar kring i rapporten vill vi särskilt understryka vikten av ett systemperspektiv i den omställning vi är inne i, samt de risker och utmaningar vi ser kopplat till att specifikt peka ut ett antal nyckelverksamheter som bör gynnas i tillståndsprövningar. Behovet av att klimatnyttan av en verksamhet ska kunna vägas in i en tillståndsprövning som gäller lokal miljöpåverkan är uppenbar men, enligt vår uppfattning, inte självklar med avseende på vilka kriterier som ska tillämpas. Vi har istället valt att föreslå ett begränsat antal (fyra) grupperingar av tekniker eller verksamheter – ”strategiska funktioner” – som vi anser är kritiska för att bidra till en effektiv klimatomställning i Sverige och för att uppnå Sveriges nationella klimatmål. Som vi beskriver i rapporten kan dessa strategiska funktioner omfatta ett antal olika tekniker och verksamheter, vilket vi ger exempel på under respektive grupp. Skälet till detta är att man då undviker att peka ut ett antal utvalda tekniker/verksamheter som särskilt viktiga, av orsaker vi resonerar kring i rapporten. Grupperingen i fyra kategorier av nyckelfunktioner ska därför ses som ett möjligt alternativ att svara på vad som skulle kunna ses som nyckelverksamheter i klimatomställningen. De kriterier som ska användas för respektive nyckelfunktion får då istället avgöras i den enskilda prövningen, men vi ger i rapporten ett antal exempel på förslag till kriterier som skulle kunna användas (även om de är långtifrån självklara, av skäl som vi också resonerar kring i rapporten).
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| 18. |
- Johnsson, Filip, 1960, et al.
(författare)
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Delrapport B2. Elektrifieringens betydelse för omställningen - till Klimaträttsutredningen M 2019:05
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna studie är dels att peka på betydelsen av elektrifieringen som åtgärd för att nå Sveriges klimatmål, dels att utreda vad detta kan komma att innebära för den framtida elanvändningen. Eftersom industrin och transportsektorn idag står för de största utsläppen av växthusgaser ligger fokus för denna studie på en analys av elektrifieringens roll i dessa sektorer. Vi kan konstatera att elektrifiering som klimatåtgärd inom industri och transport har rönt stor uppmärksamhet under de senaste åren. Det handlar bland annat om att järn- och stålindustrin, som står för de största industriella utsläppen av koldioxid i Sverige, har aviserat ett antal projekt och investeringar som, om de realiseras, helt kommer att ställa om denna bransch, kraftigt minska utsläppen av växthusgaser och väsentligt bidra till en ökad elförbrukning. Även andra industribranscher har aviserat ambitioner att ersätta fossil bränsleanvändning med el och vätgas. Men utvecklingen berör också transportsektorn där försäljningen av elfordon har tagit ordentlig fart och där flertalet prognoser pekar på att majoriteten av nybilsförsäljningen av lätta fordon kommer att utgöras av laddbara fordon innan 2030. Om denna utveckling fortgår och förstärks enligt de planer och ambitioner som finns så bedöms Sverige, genom elektrifieringen, ha goda förutsättningar att nå sitt nettonollutsläppsmål till 2045. Elektrifiering är inte den enda åtgärden som erfordras för den klimatpolitiska omställningen utan kommer att ackompanjeras av andra åtgärder som exempelvis ökad användning av biobränslen och effektiviseringar. Däremot pekar väldigt mycket på att elektrifiering kan bli den enskilt viktigaste åtgärden för att omställningen ska ske tillräckligt snabbt och i tillräcklig omfattning. Det finns dock ett antal viktiga omständigheter som kan utgöra hinder för en ökad elektrifiering och, därmed på sikt, äventyra de svenska klimatmålen. En omfattande elektrifiering av det slag som sannolikt krävs, och som analyseras i denna rapport, innebär en infrastrukturell kraftansträngning inte minst med avseende på utbyggnad av elnätsinfrastruktur och elproduktion. Ledtiderna för sådana satsningar kan av flera skäl bli mycket långdragna. Detta bidrar till ökade osäkerheter och riskerar leda till att projekt som syftar till minskade växthusgasutsläpp men som kräver ansenliga mängder el inte blir av. En genomgång av olika studier indikerar att den svenska elanvändningen kan komma att i princip fördubblas till 2050 givet att elektrifieringen blir omfattande inom industri och transporter. En omfattande elektrifiering är i grund och botten en önskvärd utveckling med tanke på klimatutmaningen. Men denna utveckling kommer också att fordra en bred samhällelig uppslutning för att bli lyckosam.
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| 19. |
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| 20. |
- Jönsson, Daniel, 1984-, et al.
(författare)
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Direct Transmittance Estimation in Heterogeneous Participating Media Using Approximated Taylor Expansions
- 2022
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 28:7, s. 2602-2614
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Tidskriftsartikel (refereegranskat)abstract
- Evaluating the transmittance between two points along a ray is a key component in solving the light transport through heterogeneous participating media and entails computing an intractable exponential of the integrated medium's extinction coefficient. While algorithms for estimating this transmittance exist, there is a lack of theoretical knowledge about their behaviour, which also prevent new theoretically sound algorithms from being developed. For this purpose, we introduce a new class of unbiased transmittance estimators based on random sampling or truncation of a Taylor expansion of the exponential function. In contrast to classical tracking algorithms, these estimators are non-analogous to the physical light transport process and directly sample the underlying extinction function without performing incremental advancement. We present several versions of the new class of estimators, based on either importance sampling or Russian roulette to provide finite unbiased estimators of the infinite Taylor series expansion. We also show that the well known ratio tracking algorithm can be seen as a special case of the new class of estimators. Lastly, we conduct performance evaluations on both the central processing unit (CPU) and the graphics processing unit (GPU), and the results demonstrate that the new algorithms outperform traditional algorithms for heterogeneous mediums.
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| 21. |
- Kegelmann, Lukas, et al.
(författare)
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It Takes Two to Tango - Double-Layer Selective Contacts in Perovskite Solar Cells for Improved Device Performance and Reduced Hysteresis
- 2017
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 9:20, s. 17245-17255
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Tidskriftsartikel (refereegranskat)abstract
- Solar cells made from inorganic-organic perovskites have gradually approached market requirements as their efficiency and stability have improved tremendously in recent years. Planar low-temperature processed perovskite solar cells are advantageous for possible large-scale production but are more prone to exhibiting photocurrent hysteresis, especially in the regular n-i-p structure. Here, a systematic characterization of different electron selective contacts with a variety of chemical and electrical properties in planar n-i-p devices processed below 180 °C is presented. The inorganic metal oxides TiO2 and SnO2, the organic fullerene derivatives C60, PCBM, and ICMA, as well as double-layers with a metal oxide/PCBM structure are used as electron transport materials (ETMs). Perovskite layers deposited atop the different ETMs with the herein applied fabrication method show a similar morphology according to scanning electron microscopy. Further, surface photovoltage spectroscopy measurements indicate comparable perovskite absorber qualities on all ETMs, except TiO2, which shows a more prominent influence of defect states. Transient photoluminescence studies together with current-voltage scans over a broad range of scan speeds reveal faster charge extraction, less pronounced hysteresis effects, and higher efficiencies for devices with fullerene compared to those with metal oxide ETMs. Beyond this, only double-layer ETM structures substantially diminish hysteresis effects for all performed scan speeds and strongly enhance the power conversion efficiency up to a champion stabilized value of 18.0%. The results indicate reduced recombination losses for a double-layer TiO2/PCBM contact design: First, a reduction of shunt paths through the fullerene to the ITO layer. Second, an improved hole blocking by the wide band gap metal oxide. Third, decreased transport losses due to an energetically more favorable contact, as implied by photoelectron spectroscopy measurements. The herein demonstrated improvements of multilayer selective contacts may serve as a general design guideline for perovskite solar cells.
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| 22. |
- Kirchartz, Thomas, et al.
(författare)
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Research Update : Recombination and open-circuit voltage in lead-halide perovskites
- 2018
-
Ingår i: APL Materials. - : AIP Publishing. - 2166-532X. ; 6:10
-
Tidskriftsartikel (refereegranskat)abstract
- The high open-circuit voltage and the slow recombination in lead-halide perovskite solar cells has been one of the main contributors to their success as photovoltaic materials. Here, we review the knowledge on recombination in perovskite-based solar cells, compare the situation with silicon solar cells, and introduce the parameters used to describe recombination and open-circuit voltage losses in solar cells. We first discuss the effect of lifetimes and surface recombination velocities on photovoltaic performance before we study the microscopic origin of charge-carrier lifetimes. The lifetimes depend on defect positions and densities and on the kinetic prefactors that control the phonon-assisted interaction between the extended states in the conduction and valence band and the localized defect states. We finally argue that the key to understand the long lifetimes and high open-circuit voltages is a combination of a low density of deep defects and a slow dissipation of energy via multiphonon processes due to the low phonon energies in the lead-halide perovskites.
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| 23. |
- Kjärstad, Jan, 1956, et al.
(författare)
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Transforming the energy system in Västra Götaland and Halland – linking short term actions to long term goals
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study analyzes pathways to meet EU, national and regional targets for CO2 emissions, energy efficiency and penetration of renewable energy in the Swedish part of the Kattegat-Skagerrak region (KASK-SE), i.e. more specifically in the counties of Västra Götaland (VGR) and Halland. Special focus is placed on four areas: The potential for energy savings in the building sector, energy savings and fuel shifting in the energy intensive industry, large-scale deployment of renewables in the electricity generation sector and greenhouse gas emission reductions in the transport sector. The energy savings are through the implementation of different energy efficiency measures.
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| 24. |
- Kronander, Joel, et al.
(författare)
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Pseudo-Marginal Metropolis Light Transport
- 2015
-
Ingår i: Proceeding SA '15 SIGGRAPH Asia 2015 Technical Briefs. - New York, NY, USA : ACM Digital Library. - 9781450339308 ; , s. 13:1-13:4
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Accurate and efficient simulation of light transport in heterogeneous participating media, such as smoke, clouds and fire, plays a key role in the synthesis of visually interesting renderings for e.g. visual effects, computer games and product visualization. However, rendering of scenes with heterogenous participating with Metropolis light transport (MLT) algorithms have previously been limited to primary sample space methods or using biased approximations of the transmittance in the scene. This paper presents a new sampling strategy for Markov chain Monte Carlo (MCMC) methods, e.g. MLT, based on pseudo-marginal MCMC. Specifically, we show that any positive and unbiased estimator of the target distribution can replace the exact quantity to simulate a Markov Chain with a stationary distribution that has a marginal which is the exact target distribution of interest. This enables us to evaluate the transmittance function with recent unbiased estimators which leads to significantly shorter rendering times. Compared to previous work, relying on (biased) ray-marching for evaluating transmittance, our method enables simulation of longer Markov chains, a better exploration of the path space, and consequently less image noise, for a given computational budget. To demonstrate the usefulness of our pseudo-marginal approach, we compare it to representative methods for efficient rendering of anisotropic heterogeneous participating media and glossy transfer. We show that it performs significantly better in terms of image noise and rendering times compared to previous techniques. Our method is robust, and can easily be implemented in a modern renderer.
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| 25. |
- Kronander, Joel, et al.
(författare)
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Real-time video based lighting using GPU raytracing
- 2014
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Ingår i: Proceedings of the 22nd European Signal Processing Conference (EUSIPCO), 2014. - : IEEE Signal Processing Society.
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Konferensbidrag (refereegranskat)abstract
- The recent introduction of HDR video cameras has enabled the development of image based lighting techniques for rendering virtual objects illuminated with temporally varying real world illumination. A key challenge in this context is that rendering realistic objects illuminated with video environment maps is computationally demanding. In this work, we present a GPU based rendering system based on the NVIDIA OptiX framework, enabling real time raytracing of scenes illuminated with video environment maps. For this purpose, we explore and compare several Monte Carlo sampling approaches, including bidirectional importance sampling, multiple importance sampling and sequential Monte Carlo samplers. While previous work have focused on synthetic data and overly simple environment maps sequences, we have collected a set of real world dynamic environment map sequences using a state-of-art HDR video camera for evaluation and comparisons.
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