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Low rank approximation in g0W0 calculations

Science China Mathematics 2016年第8期59卷 1593-1612页

作者： SHAO MeiYue LIN Lin YANg Chao LIU Fang DA JORNADA Felipe H. DESLIPPE Jack LOUIE steven g. Computational Research Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Mathematics University of California at BerkeleyBerkeleyCA 94720USA School of Statistics and Mathematics Central University of Finance and EconomicsBeijing 100081China Department of Physics University of California at BerkeleyBerkeleyCA 94720USA Materials Science Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA NERSC.Lawrence Berkeley National Laboratory Berkeley.CA 94720.USA

The single particle energies obtained in a Kohn-Sham density functional theory(DFT) calculation are generally known to be poor approximations to electron excitation energies that are measured in transport,tunneling and spectroscopic experiments such as photo-emission spectroscopy. The correction to these energies can be obtained from the poles of a single particle green's function derived from a many-body perturbation theory. From a computational perspective, the accuracy and efficiency of such an approach depends on how a self energy term that properly accounts for dynamic screening of electrons is approximated. The g_0W_0 approximation is a widely used technique in which the self energy is expressed as the convolution of a noninteracting green's function(g_0) and a screened Coulomb interaction(W_0) in the frequency domain. The computational cost associated with such a convolution is high due to the high complexity of evaluating W_0 at multiple frequencies. In this paper, we discuss how the cost of g_0W_0 calculation can be reduced by constructing a low rank approximation to the frequency dependent part of W_0. In particular, we examine the effect of such a low rank approximation on the accuracy of the g_0W_0 approximation. We also discuss how the numerical convolution of g_0 and W_0 can be evaluated efficiently and accurately by using a contour deformation technique with an appropriate choice of the contour.

关键词： density functional theory goW0 approximation Sternheimer equation contour deformation lowrank approximation

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Exploring the reasons for the seasons using google Earth, 3D models, and plots

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International Journal of Digital Earth 2017年第6期10卷 582-603页

作者： Declan g.De Paor Mladen M.Dordevic Paul Karabinos Stephen Burgin Filis Coba steven J.Whitmeyer Departments of Physics and Ocean Earthand Atmospheric SciencesOld Dominion UniversityNorfolkVAUSA Department of geology and Environmental Science James Madison UniversityHarrisonburgVAUSA Department of geosciences Williams CollegeWilliamstownMAUSA Department of Curriculum and Instruction University of ArkansasFayettevilleARUSA Department of Physics Old Dominion UniversityNorfolkVAUSA

Public understanding of climate and climate change is of broad societal ***,misconceptions regarding reasons for the seasons abound amongst students,teachers,and the public,many of whom believe that seasonality is caused by large variations in Earth’s distance from the *** may be reinforced by textbook illustrations that exaggerate eccentricity or show an inclined view of Earth’s near-circular *** explanations that omit multiple factors influencing seasons,that do not mesh with students’experiences,or that are erroneous,hinder scientifically valid *** show that many teachers share their students’misconceptions,and even when they understand basic concepts,teachers may fail to appreciate the range of factors contributing to seasonal change,or their relative *** have therefore developed a learning resource using google Earth,a virtual globe with other useful,weather-and climate-related visualizations.A classroom test of 27 undergraduates in a public research university showed that 15 improved their test scores after the google Earth-based laboratory class,whereas 5 *** correct answers rose from 4.7/10 to 6/10,giving a paired t-test value of *** using google Earth,students are helped to segue to a heliocentric view.

关键词： Visualization geo-spatial science geobrowser earth observation 3-d representation

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Real-world emission factors for Caterpillar 797B heavy haulers during mining operations

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Particuology 2016年第5期14卷 22-30页

作者： Xiaoliang Wang Judith C. Chow steven D. Kohl Kevin E. Percy Allan H. Legge John g. Watson Desert Research Institute 2215 Raggio Parkway Reno NV 895J2 USA graduate Faculty University of Nevada Reno NV89503 USA The State Key Laboratory of Loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China Wood Buffalo Environmental Association 330 Thickwood Boulevard Fort McMurray AB Canada 7DK 1 Y1 Biosphere Solutions 1610 1 lth Avenue N.W. Calgary AB Canada T2N IG9

Real-world fuel-based emission factors （EFs） from Caterpillar 797B diesel heavy haulers when used for oil sands mining operations were measured using an on-hoard portable emissions monitoring system. Average EFs （in g/kg fuel） for 16 separate tests on four trucks were 3150 ± 4 for CO2, 2.51 ± 1.30 for CH4, 10.28 ± 3.21 for CO, 0.61 ± 0.32 for non-methane hydrocarbons, 55.49 ± 9,75 for NOx （reported as NO2）, 0.70 ± 0.17 for PM2.s （mass of particles with aerodynamic diameter 〈2.5 μm）, and 0.34 ± 0.05 for black carbon （BC）. Ultrafine particle numbers averaged （4.7 ± 4.1 ） × 10^15 particleslkg fuel. Fuel-based EFs of NO, NO2, and particle numbers were higher during idling, whereas PM2.5 and BC EFs were higher during traveling without a load. A comparison of emissions with those reported by oil sands facilities showed large variations, both among the facilities and between the reported emissions and the real-world measurements.

关键词： Heavy hauler Emission Nonroad Portable emissions measurement system Mining Oil sands

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Physical characteristics of conditioned anaerobic digested sludge-A fractal, transient and dynamic rheological viewpoint

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Journal of Environmental Sciences 2011年第8期23卷 1266-1273页

作者： Yili Wang Emilie Dieude-Fauvel steven K Dentel College of Environmental Science and Engineering Beijing Forestry University Beijing 100083 China. Department of Civil and Environmental Engineering University of Delaware Newark Delaware 19711 USA Cemagref Les Palaquins 03150 Montoldre Paris France

The changes in the physical characteristics of unconditioned and conditioned anaerobic digested sludge （ADS） biosolids, such as capillary suction time （CST）, yield stress, average size and fractal dimensions, were investigated through a CST test, transient and dynamic rheological test and image analysis. The results showed that the optimum polymer dose range was observed when CST or its reciprocal value was employed as an indicator. There were good correlations between the yield stresses determined from both a controlled shear stress test and a strain amplitude sweep test. The yield stress and storage modulus （g＇） increased as the polymer dose increased in most cases. A frequency sweep test revealed that polymer conditioning could extend the frequency sweep ranges for their elastic behaviors over viscous behaviors as well as the gel-like structure in the linear viscoelastic range. These results implied that more deformation energy was stored in this rigid structure, and that elastic behavior became increasingly dominant with the addition of the polymer in most cases, In addition, both the average sizes and two-dimensional fractal dimensions for conditioned ADS biosolids presented a similar up-climax-down variation trend as the polymer doses increased, whereas the critical polymer doses at the highest average sizes or two-dimensional fractal dimensions, were different. Correlation analysis revealed that the conditioned ADS dewaterability was not correlated with the yield stresses, while the average sizes or the two-dimensional fractal dimensions for conditioned ADS biosolids could be taken as the indication parameters for ADS dewaterability.

关键词： anaerobic digested sludge conditioning dynamic oscillatory test yield stress fractal dimensions polymer dose

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The advent of structural biology in situ by single particle cryo-electron tomography

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Biophysics Reports 2017年第Z1期3卷 17-35页

作者： Jesús g.galaz-Montoya steven J.Ludtke National Center for Macromolecular Imaging Verna and Marrs McLean Department of Biochemistry and Molecular Biology Baylor College of Medicine

Single particle tomography(SPT), also known as subtomogram averaging, is a powerful technique uniquely poised to address questions in structural biology that are not amenable to more traditional approaches like X-ray crystallography, nuclear magnetic resonance, and conventional cryoEM single particle analysis. Owing to its potential for in situ structural biology at subnanometer resolution, SPT has been gaining enormous momentum in the last five years and is becoming a prominent, widely used technique. This method can be applied to unambiguously determine the structures of macromolecular complexes that exhibit compositional and conformational heterogeneity, both in vitro and in situ. Here we review the development of SPT, highlighting its applications and identifying areas of ongoing development.

关键词： Cryo-electron tomography Single particle tomography Subtomogram averaging Direct detection device Contrast transfer function

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An investigation of the L-shell x-ray conversion efficiency for laser-irradiated tin foils

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Plasma Science and Technology 2020年第4期22卷 48-54页

作者： David BAILIE Cormac HYLAND Raj L SINgH steven WHITE gianluca SARRI Francis P KEENAN David RILEY steven J ROSE Edward g HILL Feilu WANg Dawei YUAN gang ZHAO Huigang WEI Bo HAN Baoqiang ZHU Jianqiang ZHU Pengqian YANg Centre for Plasma Physics School of Mathematics and PhysicsQueen's University BelfastBelfastBT7 INNUnited Kingdom Astrophysics Research Centre School of Mathematics and PhysicsQueen's University BelfastBelfastBT7 INNUnited Kingdom Plasma Physics group Blackett LaboratoryPrince Consort RoadLondonSW72AZUnited Kingdom Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012People's Republic of China Department of Astronomy Beijing Normal UniversityBeijing 100875People's Republic of China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences.Shanghai 201800People's Republic of China

We have used the ShenguangⅡlaser in third harmonic(351 nm)to investigate the emission of L-shell radiation in the 3.3–4.4 ke V range generated using thin foils of Sn coated onto a parylene substrate with irradiation of order 1015 W cm-2 and nanosecond pulse *** our experiment,we have concentrated on assessing the emission on the non-laser irradiated side as this allows an experimental geometry relevant to experiments on photo-ionised plasmas where a secondary target must be placed close to the source,to achieve x-ray fluxes appropriate to astrophysical *** L-shell conversion efficiencies are estimated to be of order 1%,with little dependence on Sn thickness between 400 and 800 nm.

关键词： conversion efficiency laser plasma x-ray sources laboratory astrophysics

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Biomonitoring for traditional herbal medicinal products using DNA metabarcoding and single molecule, real-time sequencing

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Acta Pharmaceutica Sinica B 2018年第3期8卷 488-497页

作者： Tianyi Xin Zhichao Xu Jing Jia Christine Leon Songnian Hu Yulin Lin Subramanyam Ragupathy Jingyuan Song steven g.Newmaster Key Lab of Chinese Medicine Resources Conservation State Administration of Traditional Chinese Medicine of the People's Republic of China Institute of Medicinal Plant Development Peking Union Medical College & Chinese Academy of Medical Sciences Royal Botanic gardens Beijing Institute of genomics Chinese Academy of Sciences NHP Research Alliance Biodiversity Institute of Ontario (BIO) University of Guelph

global concerns have been paid to the potential hazard of traditional herbal medicinal products(THMPs). Substandard and counterfeit THMPs, including traditional Chinese patent medicine, health foods, dietary supplements, etc. are potential threats to public health. Recent marketplace studies using DNA barcoding have determined that the current quality control methods are not sufficient for ensuring the presence of authentic herbal ingredients and detection of contaminants/adulterants. An efficient biomonitoring method for THMPs is of great needed. Herein, metabarcoding and single-molecule, realtime(SMRT) sequencing were used to detect the multiple ingredients in Jiuwei Qianghuo Wan(JWQHW), a classical herbal prescription widely used in China for the last 800 years. Reference experimental mixtures and commercial JWQHW products from the marketplace were used to confirm the method. Successful SMRT sequencing results recovered 5416 and 4342 circular-consensus sequencing(CCS) reads belonging to the ITS2 and psb A-trn H regions. The results suggest that with the combination of metabarcoding and SMRT sequencing, it is repeatable, reliable, and sensitive enough to detect species in the THMPs, and the error in SMRT sequencing did not affect the ability to identify multiple prescribed species and several adulterants/contaminants. It has the potential for becoming a valuable tool for the biomonitoring of multi-ingredient THMPs.

关键词： Traditional herbal medic inal products(THMP) Species mixture Authentication DNA metabarcoding Single molecule real-time(SMRT) sequencing Circular-consensus sequencing(CCS)

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Long-term antifibrotic action of interferon-γ treatment in patients with chronic hepatitis B virus infection

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Hepatobiliary & Pancreatic Diseases International 2011年第2期10卷 151-157页

作者： Peter R Mertens steven Dooley Department of Nephrology and Hypertension Otto-von-Guericke-University First Affiliated Hospital Zhejiang University School of Medicine Molecular Hepatology-Alcohol Dependent Diseases II. Medical Clinic Faculty of Medicine at MannheimUniversity of Heidelberg

BACKgROUND:The first priority in treating fibrosis is to eliminate the causes that result in liver injury,e.g.,hepatitis B and C ***,in many liver diseases the cause is either unknown or *** present study was designed to investigate the long-term antifibrotic effect of interferon-gamma(IFN-γ)treatment in patients chronically infected with hepatitis B virus. METHODS:A total of 42 patients,30 treated with IFN-γand 12 controls,were enrolled from an original clinical trial(Clin gastroenterol Hepatol 2005;3:819.).Three serial liver biopsies that were obtained at the initiation and end of IFN-γtreatment as well as 4 to 6 years after treatment discontinuation were assessed according to the modified Chevallier scoring system. RESULTS:Twenty-five out of 30 IFN-γ-treated patients were followed up until 4 to 6 years after the treatment was stopped. However,all controls were excluded from follow-up due to death,loss and elevated virus level within 2 ***-five IFN-γ-treated patients had stable serum liver function and liver fibrosis indices without any further antiviral or anti-fibrotic *** inflammatory and fibrotic scores were found after nine months of IFN-γtreatment according to the modified Chevallier scoring system(inflammation:11.8±6.5 at the beginning of IFN-γtreatment vs.9.2±4.1 after 9 months, Pg them,14 patients accepted a third serial liver biopsy 4 to 6 years after treatment discontinuation,and the fibrotic score was increased(14.2±8.3 vs.11.9±7.6 after 9 months, Pgnificantly improves the fibrosis score in patients with chronic HBV *** majority of patients demonstrate stable serum biochemical indices and quality of ***,they do not show a long-term benefit according to histological criteria. given the limited sample size,long-term IFN-γtreatment regimens should be assessed in further

关键词： hepatic stellate cells hepatitis B virus liver fibrosis inflammation interferon-gamma

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Aye,Two:Langston Hughes’s Sandburgian-Whitmanian Affirmation

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Journal of Foreign Languages and Cultures 2019年第1期3卷 39-48页

作者： steven Tracy University of Massachusetts

Langston Hughes’s work must be seen in context and continuity not only with African American writers like Paul Laurence Dunbar,*** Bois,and James Weldon johnson,but with acknowledged white forebears such as Walt Whitman and Carl Sandburg.A look at poems by Whitman and Sandburg reveal a writer who modeled some of his work on the writings of the earlier poets,revealing his own aesthetic alterations to the work of these earlier writers and establishing his contribution to the American traditions of poetry.

关键词： folk identity “Negro ”Democratic Bard

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High-energy sodium-ion hybrid capacitors through nanograin-boundary-induced pseudocapacitance of Co_(3)O_(4) nanorods

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Journal of Energy Chemistry 2022年第6期31卷 338-346,I0009页

作者： Wenliang Feng Venkata Sai Avvaru steven JHinder Vinodkumar Etacheri IMDEA Materials Institute C/Eric Kandel 2GetafeMadrid 28906Spain Universidad Politécnica de Madrid E.T.S.de Ingenieros de Caminos28040 MadridSpain Universidad Autónoma de Madrid C/Francisco Tomás y Valiente728049 MadridSpain Surface Analysis Laboratory Faculty of Engineering and Physical Sciences University of Surrey GuildfordSurrey GU27XHUnited Kingdom

Sodium-ion hybrid capacitors (SICs) have been proposed to bridge performance gaps between batteries and supercapacitors,and thus realize both high energy density and power density in a single ***,applications of SICs are severely restricted by their insufficient energy densities (g) resulted from the kinetics imbalance between cathodes and ***,we report a nanograin-boundary-rich hierarchical Co_(3)O_(4) nanorod anode composed of~20 nm *** pseudocapacitance (up to 72%@1.0 mV/s) is achieved through nanograin-boundary-induced pseudocapacitive-type Na^(+) storage ***_(3)O_(4) nanorod anode delivers in this case highly reversible capacity (810 mAh/g@0.025 A/g),excellent rate capability (335 mAh/g@5.0 A/g),and improved cycle stability (100 cycles@1.0 A/g with negligible capacity degradation).The outstanding performance can be credited to the hierarchical morphology of Co_(3)O_(4) nanorods and the well-designed nanograinboundaries between nanocrystallites that avoid particle agglomeration,induce pseudocapacitive-type Na^(+) storage,and accommodate volume variation during sodiation-desodiation *** of the Co_(3)O_(4) nanorods not only generates defects for extra surficial Na^(+) storage but also increases the electronic conductivity for efficient charge separation and lowers energy barrier for Na^(+) *** of conventional reaction mechanism and pseudocapacitive-type Na^(+) storage enables high specific capacity,rapid Na^(+) diffusion,and improved structural stability of the Co_(3)O_(4) nanorod *** SIC integrating this highly pseudocapacitive anode and activated carbon cathode delivers exceptional energy density (175 Wh/kg@40 W/kg),power density (6632 W/kg@37 Wh/kg),cycle life (6000 cycles@1.0 A/g with a capacity retention of 81%),and coulombic efficiency (~100%).

关键词： Sodium-ion hybrid capacitor Cobalt oxide nanorod Nanograin-boundary Pseudocapacitance

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