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An all optical approach for comprehensive in-operando analysis of radiative and nonradiative recombination processes in GaAs double heterostructures

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Light(Science & Applications) 2022年第6期11卷 1206-1217页

作者： Fan Zhang Jose Fcastaneda Timothy Hgfroerer daniel Friedman Yong-Hang Zhang Mark wwanlass Yong Zhang Department of Electrical and Computer Engineering The University of North Carolina at CharlotteCharlotteNC 28223USA Songshan Lake Materials Laboratory DongguanGuangdong 523808China Department of Physics Davidson CollegeDavidsonNC 28035USA National Renewable Energy Laboratory GoldenCO 80401USA School of Electrical Computer and Energy EngineeringArizona State UniversityTempeAZ 85287USA wanlass Consulting NorwoodCO 81423USA

we demonstrate an all optical approach that can surprisingly offer the possibility of yielding much more information than one would expect,pertinent to the carrier recombination dynamics via both radiative and nonradiative processes when only one dominant deep defect level is present in a semiconductor *** applying a band-defect state coupling model that explicitly treats the inter-band radiative recombination and Shockley-Read-Hall(SRH)recombination via the deep defect states on an equal footing for any defect center occupation fraction,and analyzing photoluminescence(PL)as a function of excitation density over a wide range of the excitation density(e.g.,5-6 orders in magnitude),in conjunction with Raman measurements of the LO-phonon plasmon(LOPP)coupled mode,nearly all of the key parameters relevant to the recombination processes can be *** include internal quantum efficiency(IQE),minority and majority carrier density,inter-band radiative recombination rate(wr),minority carrier nonradiative recombination rate(wnr),defect center occupation fraction(f)),defect center density(Nt),and minority and majority carrier capture cross-sections(σt andσtM).while some of this information is thought to be obtainable optically,such as IQE and the wr/wnr ratio,most of the other parameters are generally considered to be attainable only through electrical techniques,such as current-voltage(Ⅰ-Ⅴ)characteristics and deep level transient spectroscopy(DLTS).Following a procedure developed herein,this approach has been successfully applied to three GaAs double-heterostructures that exhibit two distinctly different nonradiative recombination *** method greatly enhances the usefulness of the simple PL technique to an unprecedented level,facilitating comprehensive material and device characterization without the need for any device processing.

关键词： radiative defect approach

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Transitional geology and its effects on development and longwall mining in Pittsburgh Seam

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International Journal of Mining Science and Technology 2016年第1期26卷 31-37页

作者： Lu Jun Van Dyke Mark Su daniel w.H. Hasenfus Greg Geomechanical Engineer Consol Energy Inc.

This paper presents the geologic and ground control challenges that were encountered by Consol Energy＇s coal mining operations in southwestem Pennsylvania, USA. Geologic encounters, such as sandstone- to-limestone geology transition, massive sandstone channels, shale channels, pyritic rich green claystone, laminated roof, and soft floor, have significantly impacted the development and longwall mining in Consol＇s Pittsburgh Seam coal mines. Experience from different mines shows that, in the sandstone-to-limestone geology transition zone, 1.83 m high-tension, fully-grouted primary bolts employed along with 4.88 m cen- ter cable bolts at every other strap greatly improved beam building and ensured proper anchorage into the competent roof. Hydraulic fracturing of the massive sandstone was often necessary to enhance caving of the massive sandstone behind the shields to relieve pressure at the face. The presence of soft floor coupled with presence of thick floor coal and deep cover, induced excessive headgate convergence during retreat of the first right hand longwall panel. In all, it is important to explore the roof and in-seam geology in detail to delineate normal and anomalous geologic conditions prior to and during development. with diligent geologic reconnaissance, geotechnical monitoring, and assessment, site-specific geotechnical solutions have been provided to mine operations to improve safety and productivity.

关键词： Coal miningGeology transition zoneGround controlRoof bolt

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Different fundus imaging modalities and technical factors in AI screening for diabetic retinopathy:a review

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Eye and Vision 2020年第1期7卷 201-213页

作者： Gilbert Lim Valentina Bellemo Yuchen Xie Xin Q.Lee Michelle Y.T.Yip daniel S.w.Ting School of Computing National University of SingaporeSingaporeSingapore Singapore Eye Research Institute Singapore National Eye CentreSingaporeSingapore Duke-NUS Medical School National University of Singapore11 Third Hospital Road AvenueSingapore 168751Singapore Vitreo-Retinal Service Singapore National Eye Center11 Third Hospital Road AvenueSingapore 168751Singapore Artificial Intelligence in Ophthalmology Singapore Eye Research Institute11 Third Hospital Road AvenueSingapore 168751Singapore

Background:Effective screening is a desirable method for the early detection and successful treatment for diabetic retinopathy,and fundus photography is currently the dominant medium for retinal imaging due to its convenience and *** screening using fundus photographs has however involved considerable costs for patients,clinicians and national health systems,which has limited its application particularly in less-developed *** advent of artificial intelligence,and in particular deep learning techniques,has however raised the possibility of widespread automated *** text:In this review,we first briefly survey major published advances in retinal analysis using artificial *** take care to separately describe standard multiple-field fundus photography,and the newer modalities of ultrawide field photography and smartphone-based ***,we consider several machine learning concepts that have been particularly relevant to the domain and illustrate their usage with extant ***:In the ophthalmology field,it was demonstrated that deep learning tools for diabetic retinopathy show clinically acceptable diagnostic performance when using colour retinal fundus *** intelligence models are among the most promising solutions to tackle the burden of diabetic retinopathy management in a comprehensive ***,future research is crucial to assess the potential clinical deployment,evaluate the cost-effectiveness of different DL systems in clinical practice and improve clinical acceptance.

关键词： Artificial intelligence Deep learning Diabetic retinopathy Fundus photographs Retinal imaging modalities Survey

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Accelerated ovarian aging in mice by treatment of busulfan and cyclophosphamide

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第4期14卷 318-324页

作者： Yan JIANG Jing ZHAO Hui-jing QI Xiao-lin LI Shi-rong ZHANG daniel w.SONG Chi-yang YU Jian-gang GAO Key Laboratory of the Ministry of Education for Experimental Teratology and School of Life Science Shandong University Jinan First People's Hospital Dulwich College Legend Garden Campus Department of Gynecology and Obstetrics Southwest Hospital

Busulfan/cyclophosphamide(Bu/Cy) conditioning regimen has been widely used to treat cancer patients,while their effects on major internal organs in females are not fully *** treated female mice with Bu/Cy,and examined the histopathology of major internal organs on Day 30 after the *** results show that Bu/Cy treatment affected the ovaries most extensively,while it had less effect on the spleen,lungs,and kidneys,and no effect on the heart,liver,stomach,and *** better understand the effect of Bu/Cy on the ovaries,we counted follicles,and determined the levels of ovarian *** Bu/Cy-treated mice showed a reduction of primordial and primary follicles(Pwas a gradual process of follicle loss and low estradiol in Bu/Cy-treated mice;this is a profile similar to what is found in women with premature ovarian failure(POF).The Bu/Cy-treated mice may serve as a useful animal model to study the dynamics of follicle loss in women undergoing POF.

关键词： Premature ovarian failure Busulfan Cyclophosphamide Chemotherapy Mouse model

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Phenology of high-arctic butterflies and their floral resources： Species-specific responses to climate change

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Current Zoology 2014年第2期60卷 243-251页

作者： Toke T.HФYE Anne ESKILDSEN Rikke R. HANSEN Joseph J.BOwDEN Niels M.SCHMIDT w.daniel KISSLING Aarhus Institute of Advanced Studies Hoegh-Guldbergs Gade 6B bldgs. 1630-1632 DK-8000 Aarhus C Denmark Department ofBioscience Kalo Aarhus University Grenaivej 14 DK-8410 Ronde Denmark Arctic Research Centre Aarhus University C.F. Mollers Allé 8 bldg. 1110 DK-8000 Aarhus C Denmark Department of Bioscience Aarhus Aarhus University Ny Munkegade bldg. 1540 DK-8000 Aarhus C Denmark Department of Bioscience Aarhus University Frederiksborgvej 399 DK-4000 Roskilde Denmark Institute for Biodiversity and Ecosystem Dynamics (IBED) University of Amsterdam P.O. Box 94248 1090 GE AmsterdamThe Netherlands

Current global warming is particularly pronounced in the Arctic and arthropods are expected to respond rapidly to these changes. Long-term studies of individual arthropod species from the Arctic are, however, virtually absent. we examined butterfly specimens collected from yellow pitfall traps over 14 years （1996-2009） at Zackenberg in high-arctic, north-east Greenland. Specimens were previously sorted to the family level. we identified them to the species level and examined long-term species-specific phenological responses to recent summer wanning. Two species were rare in the samples （Polaris fritillary Boloria polaris and Arctic blue Plebejus glandon） and statistical analyses of phenological responses were therefore restricted to the two most abundant species （Arctic fritillary, B. chariclea and Northern clouded yellow Colias hecla）. Our analyses demonstrated a trend towards earlier flight seasons in B. chariclea, but not in C. hecla. The timing of onset, peak and end of the flight season in B. chariclea were closely related to snowmelt, July temperature and their interaction, whereas onset, peak and end of the flight season in C. hecla were only related to timing of snowmelt. The duration of the butterfly flight season was significantly positively related to the temporal overlap with floral resources in both butterfly species. we further demonstrate that yellow pitfall traps are a useful alternative to transect walks for butterfly recording in tundra habitats. More phenological studies of Arctic arthropods should be carded out at the species level and ideally be analysed in context with interacting species to assess how ongoing climate change will affect Arctic biodiversity in the near future [Current Zoology 60 （2）： 243-251, 2014].

关键词： Arctic Arthropod Flight period Greenland Pitfall trap Zackenberg

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Gait analysis in swine,sheep,and goats after neurologic injury:a literature review

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Neural Regeneration Research 2023年第9期18卷 1917-1924页

作者： Jacob w.Sveum Raveena R.Mishra Taylor L.Marti Jalon M.Jones daniel J.Hellenbrand Amgad S.Hanna Department of Neurological Surgery University of Wisconsin School of Medicine and Public Health(UWSMPH)MadisonWIUSA

Medical research on neurologic ailments requires representative animal models to validate treatments before they are translated to human clinical *** are the predominant animal model used in neurological research despite limited anatomic and physiologic similarities to *** a result,functional testing designed to assess locomotor recovery after neurologic impairment is well established in rodent ***,large r,more clinically relevant models have not been as well *** achieve similar locomotor testing standardization in larger animals,the models must be accessible to a wide array of ***-human primates are the most relevant animal model fo r translational research,however ethical and financial barriers limit their *** review focuses on swine,sheep,and goats as large animal alternatives for transitional studies between rodents and non-human *** objective of this review is to compare motor testing and data collection methods used in swine,sheep,and goats to encourage testing standardization in these larger animal *** PubMed database was analyzed by searching combinations of swine,sheep,and goats,neurologic injuries,and functional *** were categorized by animal model,data collection method,and assessment *** and sheep were used in the majority of the studies,while only two studies were found using *** functional assessments included open pen analysis,treadmill walking,and guided free *** collection methods included subjective behavioral rating scales and objective tools such as pressure-sensitive mats and image-based analysis ***,swine and sheep were well-suited for a variety of assessment designs,with treadmill walking and guided free walking offering the most consistency across multiple *** collection methods varied,but image-based gait analysis software provided the most robust *** studies should be conducted to stan

关键词： functional testing gait analysis goats large animals neurologic injury sheep spinal cord injury swine

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Targeting whole body metabolism and mitochondrial bioenergetics in the drug development for Alzheimer’s disease

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Acta Pharmaceutica Sinica B 2022年第2期12卷 511-531页

作者： Steven N.Austad Scott Ballinger Thomas w.Buford Christy S.Carter daniel L.Smith Jr Victor Darley-Usmar Jianhua Zhang Department of Biology University of Alabama at BirminghamBirminghamAL 35294USA Department of Pathology University of Alabama at BirminghamBirminghamAL 35294USA Department of Medicine University of Alabama at BirminghamBirminghamAL 35294USA Department of Nutrition Sciences University of Alabama at BirminghamBirminghamAL 35294USA

Aging is by far the most prominent risk factor for Alzheimer’s disease(AD),and both aging and AD are associated with apparent metabolic *** developing effective therapeutic interventions to treat AD is clearly in urgent need,the impact of modulating whole-body and intracellular metabolism in preclinical models and in human patients,on disease pathogenesis,have been *** is also an increasing awareness of differential risk and potential targeting strategies related to biological sex,microbiome,and circadian *** a major part of intracellular metabolism,mitochondrial bioenergetics,mitochondrial quality-control mechanisms,and mitochondria-linked inflammatory responses have been considered for AD therapeutic *** review summarizes and highlights these efforts.

关键词： Mitochondrial DNA Mitochondrial electron transport chain Mitochondrial quality control Reactive species DAMPs Hexokinase biosynthesis pathway Diabetes Circadian regulation Microbiome

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Dietary supplementation with 0.4%L-arginine between days 14 and 30 of gestation enhances NO and polyamine syntheses and water transport in porcine placentae

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Journal of Animal Science and Biotechnology 2023年第2期14卷 627-639页

作者： Cassandra M.Herring Fuller w.Bazer Gregory A.Johnson Heewon Seo Shengdi Hu Mohammed Elmetwally wenliang He daniel B.Long Guoyao wu Department of Animal Science Texas A&M UniversityCollege StationTX 77843USA Department of Veterinary Integrative Biosciences Texas A&M UniversityCollege StationTX 77843USA.

Background:Most embryonic loss in pigs occurs before d 30 of *** supplementation with L-arginine(Arg) during early gestation can enhance the survival and development of conceptuses(embryo/fetus and its extraembryonic membranes) in ***,the underlying mechanisms remain largely ***:Between d 14 and 30 of gestation,each gilt was fed daily 2 kg of a corn-and soybean-meal based diet(12% crude protein) supplemented with either 0.4% Arg(as Arg-HCl) or an isonitrogenous amount of L-alanine(Control).There were 10 gilts per treatment *** d 30 of gestation,gilts were fed either Arg-HCl or L-alanine 30 min before they were hysterectomized,followed by the collection of placentae,embryos,fetal membranes,and fetal *** and allantoic fluids were analyzed for nitrite and nitrate [NOx;stable oxidation products of nitric oxide(NO)],polyamines,and amino *** were analyzed for syntheses of NO and polyamines,water and amino acid transport,concentrations of amino acid-related metabolites,and the expression of angiogenic factors and aquaporins(AQPs).Results:Compared to the control group,Arg supplementation increased(P weight(+ 36.5%),the total weight of viable fetuses(+ 33.5%),fetal crown-to-rump length(+ 4.7%),and total allantoic and amniotic fluid volumes(+ 44.6% and + 75.5% respectively).Compared to control gilts,Arg supplementation increased(P < 0.05) placental activities of GTP cyclohydrolase-1(+ 33.1%) and ornithine decarboxylase(+ 29.3%);placental syntheses of NO(+ 26.2%) and polyamines(+ 28.9%);placental concentrations of NOx(+ 22.5%),tetrahydrobiopterin(+ 21.1%),polyamines(+ 20.4%),c AMP(+ 27.7%),and c GMP(+ 24.7%);total amounts of NOx(+ 61.7% to + 96.8%),polyamines(+ 60.7% to + 88.7%),amino acids(+ 39% to + 118%),glucose(+ 60.5% to + 62.6

关键词： Angiogenesis Arginine Fetus Placenta Reproduction

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Shear Band Formation in AISI 4340 Steel Under Dynamic Impact Loads:Modeling and Experiment

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Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 378-384页

作者： daniel Odoh Gbadebo Owolabi Akindele Odeshi Horace whitworth Department of Mechanical Engineering Howard University Department of Mechanical Engineering University of Saskatchewan57 Campus DriveSaskatoonSKS7N 5A9Canada

In this study, the occurrence of the adiabatic shear bands in AISI 4340 steel under high velocity impact loading was investigated using finite element analysis and experimental tests. The cylindrical specimen subjected to the impact load was divided into different regions separated by nodes using finite element method in ABAQUS environment with boundary conditions specified. The material properties were assumed to be lower in the region where the probability of strain localization is high based on prior experimental results in order to initialize the formation of the adiabatic shear bands. The finite element model was used to determine the maximum flow stress, the strain hardening, the thermal softening, and the time to reach the critical strain for the formation of adiabatic shear bands. Experimental results show that deformed bands were formed at low strain rates and there was a minimum strain rate required for the formation of the transformed band in the alloy and the cracks were initiated and propagated along the transformed bands leading to fragmentation under the impact loading. The susceptibility of the adiabatic shear bands to cracking was markedly influenced by the strain-rates and the initial material microstructure. The simulation results obtained were compared with the experimental results obtained from the AISI 4340 steel under high strain-rate loading in compression using split impact Hopkinson bars. A good agreement between the experimental and simulation results was obtained.

关键词： Adiabatic shear bands Finite element model Strain hardening Thermal softening Johnson-Cook model AISI 4340 steel

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BioTRIZ Suggests Radiative Cooling of Buildings Can Be Done Passively by Changing the Structure of Roof Insulation to Let Longwave Infrared Pass

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Journal of Bionic Engineering 2008年第1期5卷 55-66页

作者： Salmaan Craig David Harrison Andrew Cripps daniel Knott School of Engineering and Design Brunel UniversityLondon UB8 3PHUKBuro Happold LtdLondon W1T 1PDUK School of Engineering and Design Brunel UniversityLondon UB8 3PHUK Buro Happold Ltd London W1T 1PDUK

This paper demonstrates the application of a design tool called BioTRIZ. Its developers claim that it can be used to access biological strategies for solving engineering problems. Our aim is to design a roof for hot climates that gets free cooling through radiant coupling with the sky. The insulation in a standard roof stops the sun and convection from warming the thermal mass. But it also restricts the mass＇s longwave view of the cool sky. Different solutions to this conflict are offered by BioTRIZ. The chosen solution is to replace the standard insulation component with an open cell honeycomb. The vertical cells would allow longwave radiation to pass, while arresting convection. The solutions offered by BioTRIZ＇s technological counterpart include no such changes in structure. It is estimated that the thermal mass in the biomimetic roof would remain on average 4.5℃ cooler than in a standard roof over a year in Riyadh, Saudi Arabia.

关键词： biomimetics TRIZ BioTRIZ radiative cooling building design passive design

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