检索结果-南通市图书馆

Pedosph.re 2005年第6期15卷 695-706页

作者： h. ZEPP TANG Jia-Liang zhang Bin Geograph.cal Institute Ruhr-University Bochum D-44780 Bochum （Germany） Institute of Soil Science Chinese Academy of Sciences P.O. Box 821 Nanjing 210008 （China）

Th.s paper introduces and illustrates th. concepts of geoecological process combinations and geograph.cal or landscape dimensions by outlining th. meth.dology of a Sino-German cooperative project in South.ast Ch.na and presents th. first results of th. modelling process for th. catch.ent scale. Th. project equipped a catch.ent in subtropical South.ast Ch.na from plot scale to catch.ent scale in order to study th. h.drological and soll erosion processes. Distinct spatial differences in principal water and soil material fluxes were quantified. Deep drainage peaks occurred in May, June and July and even in August and November. Measurements in erosion plots as well as sedimentary deposits revealed th.t th.re was soil erosion connected with.overland flow. Consistent with.th. results from th. regular catenary variations of soil colors, textural stratification and h.drograph.analysis, th.re was also a clear indication of interflow from measured soil moisture data. Th. experimental set up h.s th. potential to furth.r deepen th. understanding of small-scale processes involved in lateral water fluxes and soil erosion. Th. expected results and interpretations will lead to a furth.r integration of th. collected data. In th. future, to understand matter transfer in and between landscape ecological units, agricultural influence on nutrient status and flux data will be incorporated.

关键词： catch.ent geoecological process combination landscape ecology soil erosion

Th. Log-Concavity of Kazh.an-Lusztig Polynomials of Uniform Matroids

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2023年第1期36卷 117-128页

作者： XIE Matth.w h.Y zhang Ph.lip B College of Science Tianjin University of TechnologyTianjin 300384China College of Math.matical Science Tianjin Normal UniversityTianjin 300387China

Elias,et al.(2016)conjectured th.t th. Kazh.an-Lusztig polynomial of any matroid is *** by a computer proof of Moll’s log-concavity conjecture given by Kauers and Paule,th. auth.rs use a computer algebra system to pr... 详细信息

关键词： h.lonomicFunctions Kazh.an-Lusztig polynomial log-concavity uniform matroid

Special Values for th. Riemann Zeta Function

在线全文

学校读者我要写书评

暂无评论

Journal of Applied Math.matics and Ph.sics 2021年第5期9卷 1108-1120页

作者： john h. h.inbockel Old Dominion University Norfolk Virginia USA

Th. purpose for th.s research.was to investigate th. Riemann zeta function at odd integer values, because th.re was no simple representation for th.se results. Th. research.resulted in th. closed form expression for representing th. zeta function at th. odd integer values 2n+1 for n a positive integer. Th. above representation sh.ws th. zeta function at odd positive integers can be represented in terms of th. Euler numbers E2n and th. polygamma functions ψ(2n)(3/4). Th.s is a new result for th.s study area. For completeness, th.s paper presents a review of selected properties of th. Riemann zeta function togeth.r with.h.w th.se properties are derived. Th.s paper will summarize h.w to evaluate zeta (n) for all integers n different from 1. Also as a result of th.s research. one can obtain a closed form expression for th. Dirich.et beta series evaluated at positive even integers. Th. results presented enable one to construct closed form expressions for th. Dirich.et eta, lambda and beta series evaluated at odd and even integers. Closed form expressions for Apéry’s constant zeta (3) and Catalan’s constant beta (2) are also presented.

关键词： Riemann Zeta Function Zeta (2n) Zeta (2n + 1) Apéry’s Constant Catalan Constant

h.bble Expansion as an Einstein Curvature

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Ph.sics 2022年第6期13卷 969-991页

作者： john h. Marr Unit of Computational Science Building 250 Babraham Research Campus Cambridge UK

Extending th. spacetime manifold of general relativity (GR) to incorporate th. h.bble expansion of space as a specific curvature, generates a modified solution with.th.ee additional non-zero Ch.istoffel symbols and a reformulated Ricci tensor and curvature. Th. observational consequences of th.s reformulation are compared with.th. ΛCDM model for luminosity distance using th. extensive type 1a supernovae (SNe 1a) data with.redsh.ft corrected to th. CMB, and for angular diameter distance using th. recent baryonic acoustic oscillation (BAO) data. For th. SNe 1a data, th. modified GR and ΛCDM models differ by mag. over zcmb = 0.01 - 1.3, with.overall weigh.ed RMS errors of ±0.136μB mag for modified GR and ±0.151μB mag for ΛCDM respectively. Th. BAO measures span a range z = 0.106 - 2.36, with.weigh.ed RMS errors of ±0.034 Mpc with.h.sub>0 = 67.6 ± 0.25 for th. modified GR model, and ±0.085 Mpc with.h.sub>0 = 70.0 ± 0.25 for th. ΛCDM model. Th. derived GR metric for th.s new solution describes both.th. SNe 1a and th. BAO observations with.comparable accuracy to th. w’ΛCDM model. By incorporating th. h.bble expansion of space with.n general relativity as a specific curvature term, th.se observations may be described with.ut requiring additional parameters for eith.r dark matter or accelerating dark energy.

关键词： h.bble Expansion General Relativity Luminosity Distance Angular Diameter Distance Dark Mass Dark Energy

Boosting corticospinal system synaptic plasticity to recover motor functions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2023年第10期18卷 2182-2183页

作者： Weiguo Song john h.Martin Feinstein Institutes for Medical Research ManhassetNYUSA Department of Molecular Cellularand Biomedical SciencesCenter for Discovery and Innovation Neuroscience Program Graduate Center of the City University of New YorkNew YorkNYUSA

An importa nt strategy to promote voluntary movements after motor system injury is to strength.n th. connections between th. motor cortex and muscles by taking advantage of th. plasticity of th. corticospinal motor *** neuromodulation approach.s are directed to activate th. spinal cord and periph.ral axons to strength.n muscle *** discuss in th.s perspective th.t,th. cortex and spinal cord sh.uld be ta rgeted togeth.r to enh.nce cortex-to-musclefunction(Amer and Martin,2022).

关键词： plasticity system activation

Embedding ZnSe nanodots in nitrogen-doped h.llow carbon arch.tectures for superior lith.um storage

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第2期11卷 966-978页

作者： Ziliang Ch.n Renbing Wu h.o Wang Kelvin h. L. zhang Yun Song Feilong Wu Fang Fang Dalin Sun Department of Materials Science Fudan University Sh.ngh.i Ch.na College of Ch.mistry and Ch.mical Engineering Xiamen University Xiamen Ch.na

Transition metal ch.lcogenides represent a class of th. most promising alternative electrode materials for h.gh.performance lith.um-ion batteries （LIBs） owing to th.ir h.gh.th.oretical capacities. h.wever, th.y suffer from large volume expansion, particle agglomeration, and low conductivity during ch.rge/disch.rge processes, leading to unsatisfactory energy storage performance. In order to address th.se issues, we rationally designed th.ee-dimensional （3D） h.brid composites consisting of ZnSe nanodots uniformly confined with.n a N-doped porous carbon network （ZnSe ND@N-PC） obtained via a convenient pyrolysis process. Wh.n used as anodes for LIBs, th. composites exh.bited outstanding electroch.mical performance, with.a h.gh.reversible capacity （1,134 mA.h.g-1 at a current density of 600 mA.g-1 after 500 cycles） and excellent rate capability （696 and 474 mA.h.g-1 at current densities of 6.4 and 12.8 A.g-1, respectively）. Th. significantly improved lith.um storage performance can be attributed to th. 3D arch.tecture of th. h.brid composites, wh.ch.not only mitigated th. internal mech.nical stress induced by th. volume ch.nge and formed a 3D conductive network during cycling, but also provided a large reactive area and reduced th. lith.um diffusion distance. Th. strategy reported h.re may open a new avenue for th. design of oth.r multi functional composites towards h.gh.performance energy storage devices.

关键词： h.llow h.brid composite ZnSe nanodot porous carbon network lith.um-ion batteries

Template-directed synth.sis of nitrogen- and sulfur- codoped carbon nanowire aerogels with.enh.nced electrocatalytic performance for oxygen reduction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2017年第6期10卷 1888-1895页

作者： Sh.ofang Fu Ch.ngzh.u Zh. Junh.a Song Mark h. Engelh.rd Xiaolin Li Peina zhang h.ibing Xia Dan Du Yueh. Lin Sch.ol of Mech.nical and Materials Engineering Washington State University WA 99164 USA Environmental Molecular Science Laboratory Pacific Northwest National Laboratory Richland WA 99354 USA Energy and Environmental Directory Pacific Northwest National Laboratory Richland WA 99354 USA State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

h.teroatom doping, precise composition control and rational morph.logy design are efficient strategies for producing novel nanocatalysts for th. oxygen reduction reaction （ORR） in fuel cells. h.rein, a cost-effective approach.to synth.size nitrogen- and sulfur-codoped carbon nanowire aerogels using a h.rd templating meth.d is proposed. Th. aerogels prepared using a combination of h.droth.rmal treatment and carbonization exh.bit good catalytic activity for th. ORR in alkaline solution. At th. optimal annealing temperature and mass ratio between th. nitrogen and sulfur precursors, th. resultant aerogels sh.w comparable electrocatalytic activity to th.t of a commercial Pt/C catalyst for th. ORR. Importantly, th. optimized catalyst sh.ws much.better long-term stability and satisfactory tolerance for th. meth.nol crossover effect. Th.se codoped aerogels are expected to h.ve potential applications in fuel cells.

关键词： h.teroatom-doped carbons porous nanomaterials aerogels metal-free catalysts oxygen reduction reaction

An Improvement on th. Efficiency of a Single Rotor Transonic Compressor by Reducing th. Sh.ck Wave Strength.on th. Blade Suction Surfaces

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Th.rmal Science 2012年第2期21卷 127-135页

作者： S. J. Geng N. X. Ch.n h. W. zhang W. G. h.ang Institute of Engineering Th.rmoph.sics Chinese Academy of Sciences EO. Box 2706 Beijing 100190 China

It is well known th.t increasing th. rotational velocity is an effective way to increase th. total pressure ratio. With.increasing flow velocity especially under th. condition of transonic flow in th. supersonic region, wh.re exist strong sh.ck waves, th. sh.ck wave loss becomes main and important. Simultaneously, th.re occurs boundary layer separation due to th. sh.ck wave / boundary layer interaction. In th. present paper th. transonic compressor blades were studied and analyzed to find a proper and simple way to reduce th. sh.ck wave loss by optimizing th. suction surface configuration or controlling th. gradient of isentropic Mach.number on th. suction surface. A Navier-Stokes solver combined with.a modified design algorith. was developed and used. Th. NASA single rotor for transonic flow compressor was served as a numerical example to sh.w th. effectiveness of th.s meth.d. Two cases for both.original and modified rotors were analyzed and compared.

关键词： Transonic compressor sh.ck wave loss efficiency improvement blade optimization

Screening ionic liquids for efficiently extracting perfluoroalkyl ch.micals (PFACs) from wastewater

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第5期127卷 866-874页

作者： Kaih.ng zhang David Kujawski Ch.is Spurrell Bing Wang john CCrittenden Brook Byers Institute of Sustainable Systems and Sch.ol of Civil and Environmental Engineering Georgia Institute of TechnologyAtlantaGA 30332USA Refinery Water Engineering and Associates Hydrocarbon Processing Water and Waste TechnologyInc.HoustonTX 77042USA Ch.vron USA VancouverWA 98664USA Sch.ol of Municipal and Environmental Engineering Shenyang Jianzhu UniversityShenyang 110000China

Liquid-liquid extraction(LLE)using ionic liquids(ILs)-based meth.ds to remove perfluoroalkyl ch.micals(PFACs),such.as perfluorooctanoic acid(PFOA)and perfluorooctane sulfonic acid(PFOS),from wastewater,is an important ***,th. lack of ph.sicoch.mical and LLE data limits th. selection of th. most suitable ILs for th. extraction of *** th.s work,1763 ILs for PFACs extraction from water were systematically screened using COSMOth.rm to estimate th. infinite dilution activity coefficient(lnγ^(∞))of PFOA and PFOS in water and *** evaluate th. accuracy of COSMOth.rm,8 ILs with.various lnγ^(∞)values were selected,and th.ir extraction efficiency(E)and distribution coefficient(D_(exp))were measured *** results sh.wed th.t th. predicted lnγ^(∞)decreased as th. increase of experimental extraction efficiency of PFOA or PFOS,wh.le th. tendency of predicted distribution coefficient(D_(pre))was consistent with.th. experimental(D_(exp))*** work provides an efficient basis for selecting ILs for th. extraction of PFACs from wastewater.

关键词： Conductor-like screening model for real solvents(COSMO-RS) Ionic liquids Perfluorooctanoic acid(PFOA) Perfluorooctane sulfonic acid(PFOS) Liquid-liquid extraction

Space- and ground-based CO_2 measurements： A review

在线全文

学校读者我要写书评

暂无评论

Science Ch.na Earth.Sciences 2016年第11期59卷 2089-2097页

作者： YUE TianXiang zhang LiLi Zh.O MingWei WANG YiFu john WILSON State Key Laboratory of Resources and Environment Information System Institute of Geographical Science and Natural Resources Research Beijing 100101 China Jiangsu Center for Collaborative Innovation in Geograph.cal Information Resource Development and Application Nanjing 210046 China Anh.i Center for Collaborative Innovation in Geograph.cal Information Integration and Application Chuzhou University Chuzhou 239012 China Spatial Sciences Institute University of Southern California Los Angles CA90089-0374 USA

Th. climate warming is mainly due to th. increase in concentrations of anth.opogenic greenh.use gases, of wh.ch.CO_2 is th. most important one responsible for radiative forcing of th. climate. In order to reduce th. great estimation uncertainty of atmosph.ric CO_2 concentrations, several CO_2-related satellites h.ve been successfully launch.d and many future greenh.use gas monitoring missions are planned. In th.s paper, we review th. development of CO_2 retrieval algorith.s, spatial interpolation meth.ds and ground observations. Th. main findings include: 1) current CO_2 retrieval algorith.s only partially account for atmosph.ric scattering effects; 2) th. accurate estimation of th. vertical profile of greenh.use gas concentrations is a long-term ch.llenge for remote sensing tech.iques; 3) ground-based observations are too sparse to accurately infer CO_2 concentrations on regional scales; and 4) accuracy is th. primary ch.llenge of satellite estimation of CO_2 concentrations. Th.se findings, taken as a wh.le, point to th. need to develop a h.gh.accuracy meth.d for simulation of carbon sources and sinks on th. basis of th. fundamental th.orem of Earth.s surface modelling, wh.ch.is able to efficiently fuse space- and ground-based measurements on th. one h.nd and work with.atmosph.ric transport models on th. oth.r h.nd.

关键词： Accuracy Carbon satellites Retrieval algorith.s Space-and ground-based measurements h.SM