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InP/GaInP nanowire tunnel diodes

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Nano Research 2018年第5期11卷 2523-2531页

作者： Xulu Zeng Gaute Otnes magnus Heurlin Renato T Mourao magnus T Borgstrom Solid State Physics NanoLund Department of Physics Lund University P.O. Box 118 Lund 5E-22100 Sweden Instituto de Fisica Universidade Federal do Rio de Janeiro Caixa Postal 68528 Rio de Janeiro 21941-972 Brazil

Semiconductor nanowire （NW） solar cells with a single p-n junction have exhibited efficiency comparable to that of their planar counterparts with a substantial reduction in material consumption. Tandem geometry is a path toward the fabrication of devices with even higher efficiencies, for which a key step is the fabrication of tunnel （Esaki） diodes within NWs with the correct diameter, pitch, and material combination for maximized efficiency. InP/GaInP and GaInP/InP NW tunnel diodes with band gap combinations corresponding to high-efficiency solar energy harvesting were fabricated and their electrical characteristics and material properties were compared. Four different configurations, with respect to material composition and doping, were investigated. The NW arrays were grown with metal-organic vapor-phase epitaxy from Au particles by use of nano-imprint lithography, metal evaporation and lift-off. Electrical measurements showed that the NWs behave as tunnel diodes in both InP （bottom）/GaInP （top） and GaInP （bottom）/InP （top） configurations, exhibiting a maximum peak current density of 25 A/cm^2, and maximum peak to valley current ratio of 2.5 at room temperature. The realization of NW tunnel diodes in both InP/GaInP and GaInP/InP configurations represent an opportunity for the use of NW tandem solar cells, whose efficiency is independent of the growth order of the different materials, increasing the flexibility regarding dopant incorporation polarity.

关键词： nanowire tunnel diode InP GaInP tandem junction solar cell

Laparoscopic revolution in bariatric surgery

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World Journal of Gastroenterology 2014年第41期20卷 15135-15143页

作者： magnus Sundbom Department of Surgical Sciences Uppsala University

The history of bariatric surgery is investigational. Dedicated surgeons have continuously sought for an ideal procedure to relieve morbidly obese patients from their burden of comorbid conditions, reduced life expectancy and low quality of life. The ideal procedure must have low complication risk, both in short- and long term, as well as minimal impact on daily life. The revolution of laparoscopic techniques in bariatric surgery is described in this summary. Advances in minimal invasive techniques have contributed to reduced operative time, length of stay, and complications. The development in bariatric surgery has been exceptional, resulting in a dramatic increase of the number of procedures performed world wide during the last decades. Although, a complex bariatric procedure can be performed with operative mortality no greater than cholecystectomy, specific procedure-related complications and other drawbacks must be taken into account. The evolution of laparoscopy will be the legacy of the 21st century and at present, day-care surgery and further reduction of the operative trauma is in focus. The impressive effects on comorbid conditions have prompted the adoption of minimal invasive bariatric procedures into the field of metabolic surgery.

关键词： Laparoscopy Bariatric surgery Minimal invasive surgery Gastric bypass Duodenal switch Gastric banding Metabolic surgery

Use of Microwave Radiances from Metop-C and Fengyun-3 C/D Satellites for a Northern European Limited-area Data Assimilation System

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Advances in Atmospheric Sciences 2021年第8期38卷 1415-1428页

作者： magnus LINDSKOG Adam DYBBROE Roger RANDRIAMAMPIANINA Swedish Meteorological and Hydrological Institute Folkborgsvägen 1760361 NorrköpingSweden Norwegian Meteorological Institute Henrik Mohns Plass 10371 OsloNorway

MetCoOp is a Nordic collaboration on operational Numerical Weather Prediction based on a common limited-area km-scale ensemble system. The initial states are produced using a 3-dimensional variational data assimilation scheme utilizing a large amount of observations from conventional in-situ measurements, weather radars, global navigation satellite system, advanced scatterometer data and satellite radiances from various satellite platforms. A version of the forecasting system which is aimed for future operations has been prepared for an enhanced assimilation of microwave radiances. This enhanced data assimilation system will use radiances from the Microwave Humidity Sounder, the Advanced Microwave Sounding Unit-A and the Micro-Wave Humidity Sounder-2 instruments on-board the Metop-C and Fengyun-3 C/D polar orbiting satellites. The implementation process includes channel selection, set-up of an adaptive bias correction procedure, and careful monitoring of data usage and quality control of observations. The benefit of the additional microwave observations in terms of data coverage and impact on analyses, as derived using the degree of freedom of signal approach, is demonstrated. A positive impact on forecast quality is shown, and the effect on the precipitation for a case study is examined. Finally, the role of enhanced data assimilation techniques and adaptions towards nowcasting are discussed.

关键词： data assimilation regional numerical weather prediction microwave radiances

Absorption of light in InP nanowire arrays

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Nano Research 2014年第6期7卷 816-823页

作者： Nicklas Anttu Alireza Abrand Damir Asoli magnus Heurlin Ingvar Aberg Lars Samuelson magnus Borgstrom Division of Solid State Physics and the Nanometer Structure Consortium at Lund University (nmC@LU) Lund University Box 118 Lund 22100 Sweden Sol Voltaics AB Ideon Science Park Scheelevagen 17 Lund 22370 Sweden

An understanding of the absorption of light is essential for efficient photovoltaic and photodetection applications with III-V nanowire arrays. Here, we correlate experiments with modeling and verify experimentally the predicted absorption of light in InP nanowire arrays for varying nanowire diameter and length. We find that 2,000 nm long nanowires in a pitch of 400 nm can absorb 94% of the incident light with energy above the band gap and, as a consequence, light which in a simple ray-optics description would be travelling between the nanowires can be efficiently absorbed by the nanowires. Our measurements demonstrate that the absorption for long nanowires is limited by insertion reflection losses when light is coupled from the air top-region into the array. These reflection losses can be reduced by introducing a smaller diameter to the nanowire-part closest to the air top-region. For nanowire arrays with such a nanowire morphology modulation, we find that the absorptance increases monotonously with increasing diameter of the rest of the nanowire.

关键词： indium phosphide semiconductor nanowire absorption of light

Sound Propagation Properties of the Discrete-Velocity Boltzmann Equation

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Communications in Computational Physics 2013年第3期13卷 671-684页

作者： Erlend magnus Viggen Department of Electronics and Telecommunications Norwegian University of Science and Technology(NTNU)7034 TrondheimNorway

As the numerical resolution is increased and the discretisation error decreases,the lattice Boltzmann method tends towards the discrete-velocity Boltzmann equation(DVBE).An expression for the propagation properties of plane sound waves is found for this *** expression is compared to similar ones from the NavierStokes and Burnett models,and is found to be closest to the *** anisotropy of sound propagation with the DVBE is examined using a two-dimensional velocity *** is found that both the anisotropy and the deviation between the models is negligible if the Knudsen number is less than 1 by at least an order of magnitude.

关键词： Lattice Boltzmann method discrete-velocity Boltzmann equation sound propagation computational aeroacoustics

Strategies to obtain pattern fidelity in nanowire growth from large-area surfaces patterned using nanoimprint lithography

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Nano Research 2016年第10期9卷 2852-2861页

作者： Gaute Otnes magnus Heurlin Mariusz Graczyk Jesper Wallentin Daniel Jacobsson Alexander Berg Ivan Maximov magnus T. Borgstrom Solid State Physics Lund University Box 118 S-22100 Lund Sweden

Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires.

关键词： semiconductor nanowire nanoimprint lithography metal-organic vaporphase epitaxial (MOVPE) patterning

Development and characterization of photovoltaic tandemjunction nanowires using electron-beam-induced current measurements

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Nano Research 2022年第9期15卷 8510-8515页

作者： Lukas Hrachowina Enrique Barrigón magnus T.Borgström NanoLund and Divison of Solid State Physics Lund UniversityBox 11822100 LundSweden Universidad de Málaga Andalucía TechDepartamento de Física Aplicada ⅠCampus de Teatinoss/nMálaga 29071Spain

Nanowires have many interesting properties that are of advantage for solar cells,such as the epitaxial combination of latticemismatched materials without plastic *** could be utilized for the synthesis of axial tandem-junction nanowire solar cells with high efficiency at low material ***-beam-induced current measurements have been used to optimize the performance of single-junction nanowire solar ***,we use electron-beam-induced current measurements to break the barrier to photovoltaic tandem-junction *** particular,we identify and subsequently prevent the occurrence of a parasitic junction when combining an InP n-i-p junction with a tunnel ***,we demonstrate how to use optical and electrical biases to individually measure the electron-beam-induced current of both sub-cells of photovoltaic tandem-junction *** show that with an applied voltage in forward direction,all junctions can be analyzed *** development of this characterization technique enables further optimization of tandem-junction nanowire solar cells.

关键词： Ⅲ-Ⅴnanowire nanowire solar cell tandem-junction Esaki tunnel diode electron-beam induced current(EBIC)

Behavioral dependent dispersal in the invasive round goby Neogobius melanostomus depends on population age

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Current Zoology 2015年第3期61卷 529-542页

作者： magnus THORLACIUS Gustav HELLSTROM Tomas BRODIN Department of Ecology and Environmental Science Umea University Linnaeus v/ig 6 90187 Umeh Sweden

Biological invasions cause major ecological and economic costs in invaded habitats. The round goby Neogobius me- lanostomus is a successful invasive species and a major threat to the biodiversity and ecological function of the Baltic Sea. It is native to the Ponto-Caspian region and has, via ballast water transport of ships, invaded the Gulf of Gdansk in Poland. Since 1990, it has spread as far north as Raahe in Northern Finland （64~41 ＂04＂N, 24~28＂44＂E）. Over the past decade, consistent indi- vidual differences of behavioral expressions have been shown to explain various ecological processes such as dispersal, survival or reproduction. We have previously shown that new and old populations differ in personality trait expression. Individuals in new populations are bolder, less sociable and more active than in old populations. Here we investigate if the behavioral differentiation can be explained by phenotype-dependent dispersal. This was investigated by measuring activity, boldness and sociability of in- dividually marked gobies, and subsequently allowing them to disperse in a system composed of five consecutive tanks connected by tubes. Individual dispersal tendency and distance was measured. Our results revealed that in newly established populations, more active individuals disperse sooner and that latency of a group to disperse depends on the mean sociability of the group. This indicates the presence of personality dependent dispersal in this species and that it is maintained at the invasion front but lost as the populations get older

关键词： Personality Activity Dispersal Round goby Neogobius melanostomus Species invasions

Time trends and outcomes of gastrostomy placement in a Swedish national cohort over two decades

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World Journal of Gastroenterology 2024年第10期30卷 1358-1367页

作者： Martin Löfling Skogar magnus Sundbom Department of Surgical Sciences Uppsala UniversityUppsala 75185Sweden

BACKGROUND Percutaneous endoscopic gastrostomy(PEG)and laparoscopically inserted gastrostomy have become the gold standard for adult patients and children,respectively,requiring long-term enteral nutrition ***-related mortality is a rare event,often reported to be zero in smaller *** data on 30-d mortality and long-term survival rates after gastrostomy placement are scarce in the *** To study the use of gastrostomies in Sweden from 1998-2019 and to analyze procedure-related mortality and short-term(<30 d)and long-term *** In this retrospective,population-based cohort study,individuals that had received a gastrostomy between 1998-2019 in Sweden were *** were identified in the Swedish National Patient Register,and survival analysis was possible by cross-referencing the Swedish Death *** cohort was divided into three age groups:Children(0-18 years);adults(19-64 years);and elderly(≥65 years).Kaplan-Meier with log-rank test and Cox regression were used for survival *** In total 48682 individuals(52%males,average age 60.9±25.3 years)were *** cohort consisted of 12.0%children,29.5%adults,and 58.5%*** increased use of gastrostomies was observed during the study period,from 13.7/100000 to 22.3/100000 individuals(P<0.001).The use of PEG more than doubled(about 800 to 1800/year),with a corresponding decrease in open gastrostomy(about 700 to 340/year).Laparoscopic gastrostomy increased more than ten-fold(about 20 to 240/year).Overall,PEG,open gastrostomy,and laparoscopic gastrostomy constituted 70.0%(n=34060),23.3%(n=11336),and 4.9%(n=2404),***-related mortality was 0.1%(n=44)overall(PEG:0.05%,open:0.24%,laparoscopic:0.04%).The overall 30-d mortality rate was 10.0%(PEG:9.8%,open:12.4%,laparoscopic:1.7%)and decreased from 11.6%in 1998-2009 vs 8.5%in 2010-2019(P<0.001).One-year and ten-year survival rates for children,adults,and elderly were 93.7%,67.5%,a

关键词： Gastrostomy Percutaneous endoscopic gastrostomy Dysphagia Enteral nutrition Long-term Survival Complication