检索结果-南通市图书馆

Journal of Computational Mathematics 2007年第5期25卷 531-542页

作者： zhongxiao jia yuquan sun Department of Mathematical Sciences Tsinghua University Beijing 100084 China

Based on the generalized minimal residual （GMRES） principle, Hu and Reichel proposed a minimal residual algorithm for the Sylvester equation. The algorithm requires the solution of a structured least squares problem. They form the normal equations of the least squares problem and then solve it by a direct solver, so it is susceptible to instability. In this paper, by exploiting the special structure of the least squares problem and working on the problem directly, a numerically stable QR decomposition based algorithm is presented for the problem. The new algorithm is more stable than the normal equations algorithm of Hu and Reichel. Numerical experiments are reported to confirm the superior stability of the new algorithm.

关键词： Least-squares solution Preconditioning Generalized singular value decomposition.

Influence of CdS films synthesized by different methods on the photovoltaic performance of CdTe/CdS thin film solar cells

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第9期29卷 615-621页

作者： Jun Wang yuquan Wang Cong Liu Meiling sun Cao Wang Guangchao Yin Fuchao jia Yannan Mu Xiaolin Liu Haibin Yang School of Physics and Optoelectronic Engineering Shandong University of TechnologyZibo 255000China Department of Physics and Chemistry Heihe UniversityHeihe 164300China State Key Laboratory of Superhard Materials Jilin UniversityChangchun 130012China

The cadmium sulphide (CdS) film is grown on cadmium telluride (CdTe) nanorods (NRs) arrays by different methods such as chemical bath deposition (CBD), magnetron sputtering (MS), and homogenous precipitation (HP) techniques. The impact of various deposition methods is explored in detail on the growth of CdTe/CdS composite film, the CdTe/CdS interface property, and solar cell efficiency. Compared to the CBD and HP methods, the MS method can improve the growth of the CdS on CdTe NRs with high crystalline quality. The device based on the CdS film prepared by the MS method demonstrates excellent photovoltaic performance, which has the potential for applications in solar cells.

关键词： CdS chemical bath deposition magnetron sputtering homogenous precipitation

计算矩阵函数双线性形式的Krylov子空间算法的误差分析

在线全文

学校读者我要写书评

暂无评论

计算数学 2020年第1期42卷 117-130页

作者：贾仲孝孙晓琳清华大学数学科学系北京100084

矩阵函数的双线性形式u^Tf(A)v出现在很多应用问题中,其中u,v∈R^n,A∈R^(n×n),f(z)为给定的解析函数.开发其有效可靠的数值算法一直是近年来学术界所关注的问题,其中关于其数值算法的停机准则多种多样,但欠缺理论支持,可靠性存疑.本... 详细信息

矩阵函数的双线性形式u^Tf(A)v出现在很多应用问题中,其中u,v∈R^n,A∈R^(n×n),f(z)为给定的解析函数.开发其有效可靠的数值算法一直是近年来学术界所关注的问题,其中关于其数值算法的停机准则多种多样,但欠缺理论支持,可靠性存疑.本文将对矩阵函数的双线性形式u^T f(A)v的数值算法和后验误差估计进行研究,给出其基于Krylov子空间算法的误差分析,导出相应的误差展开式,证明误差展开式的首项是一个可靠的后验误差估计,据此可以为算法设计出可靠的停机准则.

关键词：双线性形式 Krylov子空间方法相对误差估计停机准则

Two-year interactions between invasive Solidago canadensis and soil decrease its subsequent growth and competitive ability

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2015年第6期8卷 617-622页

作者： Li-jia Dong Zhen-Kai sun Yan Gao Wei-Ming He State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesNo.20 NanxincunXiangshan RoadHaidian DistrictBeijing 100093China College of Life Sciences University of Chinese Academy of SciencesNo.19 Yuquan RoadShijingshan DistrictBeijing 100049China

Aims Plant-soil interaction(PsI)has been implicated as a causative mechanism promoting plant invasions,and some mechanisms underlying PsI effects remain ***,we attempted to address how altered soil microbes and nutrients influence PsI *** soil was cultured by an invasive forb Solidago canadensis for two *** conducted an experiment,in which *** and Chinese natives were grown either alone or together in control and cultured soils,and determined the growth of *** and five natives and the competitive ability of *** ana-lyzed the microbial community composition and nutrients of two types of *** Findings Compared to the control soil,the soil cultured by *** decreased the subsequent growth of *** and five Chinese natives,as well as the competitive ability of *** against Chinese *** microbial community composition was significantly altered due to soil *** fatty acids,bacte-ria,gram-negative bacteria and gram-positive bacteria had no responses to soil culturing;fungi,aerobic bacteria and fungi/bacteria ratio significantly decreased with soil culturing;anaerobes and gram-negative/positive bacteria ratio greatly increased with soil *** nitrogen(N)dramatically decreased with soil culturing,whereas soil phosphorus(P)was *** results suggest that negative PsI effects may be linked to decreases in soil fungi,aerobic bacteria and soil N and increases in soil anaerobic bacteria and the ratio of gram-negative/positive *** find-ings provide an initial indication that ***-soil interaction alone could exhibit limited contributions to its success in the early stage of invasion.

关键词： competitive outcome growth plant-soil interaction soil microbes soil nutrients

Nonvolatile and reconfigurable two-terminal electro-optic duplex memristor based on Ⅲ-nitride semiconductors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第4期13卷 706-716页

作者： Zhiwei Xie Ke jiang Shanli Zhang jianwei Ben Mingrui Liu Shunpeng Lv Yang Chen Yuping jia Xiaojuan sun Dabing Li State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesDongnanhu Road No.3888Changchun 130033China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesYuquan Road No.19100049 BeijingChina

With the fast development of artificial intelligence(AI),Internet of things(IOT),etc,there is an urgent need for the technology that can efficiently recognize,store and process a staggering amount of *** AlScN material has unique advantages including immense remnant polarization,superior temperature stability and good latticematch to other III-nitrides,making it easy to integrate with the existing advanced III-nitrides material and device ***,due to the large band-gap,strong coercive field,and low photo-generated carrier generation and separation efficiency,it is difficult for AlScN itself to accumulate enough photo-generated carriers at the surface/interface to induce polarization inversion,limiting its application in in-memory sensing and *** this work,an electro-optic duplex memristor on a GaN/AlScN hetero-structure based Schottky diode has been *** twoterminal memristor shows good electrical and opto-electrical nonvolatility and *** both electrical and opto-electrical modes,the current on/off ratio can reach the magnitude of 104,and the resistance states can be effectively reset,written and long-termly *** on this device,the“IMP”truth table and the logic“False”can be successfully reproduced,indicating the huge potential of the device in the field of in-memory sensing and computing.

关键词： polarization duplex limiting

Histones released by NETosis enhance the infectivity of SARS-CoV-2 by bridging the spike protein subunit 2 and sialic acid on host cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2022年第5期19卷 577-587页

作者： Weiqi Hong Jingyun Yang Jun Zou Zhenfei Bi Cai He Hong Lei Xuemei He Xue Li Aqu Alu Wenyan Ren Zeng Wang Xiaohua jiang Kunhong Zhong Guowen jia Yun Yang Wenhai Yu Qing Huang Mengli Yang Yanan Zhou Yuan Zhao Dexuan Kuang Junbin Wang Haixuan Wang Siyuan Chen Min Luo Ziqi Zhang Tiangi Lu Li Chen Haiying Que Zhiyao He Qiu sun Wei Wang Guobo Shen Guangwen Lu Zhiwei Zhao Li Yang Jinliang Yang Zhenling Wang Jiong Li Xiangrong Song Lunzhi Dai Chong Chen jia Geng Maling Gou Lu Chen Haohao Dong Yong Peng Canhua Huang Zhiyong Qian Wei Cheng Changfa Fan yuquan Wei Zhaoming Su Aiping Tong Shuaiyao Lu Xiaozhong Peng Xiawei Wei Laboratory of Aging Research and Cancer Drug Targeting State Key Laboratory of Biotherapy and Cancer CenterNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityNo.17Block 3Southern Renmin RoadChengduSichuan610041China National Kunming High-level Biosafety Primate Research Center Institute of Medical BiologyChinese Academy of Medical Sciences and Peking Union Medical CollegeYunnanChina Westvac Biopharm Co. Ltd.No.618Fenghuang RoadShuangliu DistrictChengduSichuanChina Division of Animal Model Research Institute for Laboratory Animal ResourcesNational Institutes for Food and Drug Control102629BeijingChina State Key Laboratory of Medical Molecular Biology Department of Molecular Biology and BiochemistryInstitute of Basic Medical SciencesMedical Primate Research CenterNeuroscience CenterChinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijingChina

Neutrophil extracellular traps(NETs)can capture and kill viruses,such as influenza viruses,human immunodeficiency virus(HIV),and respiratory syncytial virus(RSV),thus contributing to host *** to our expectation,we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2,as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse *** histone H3 or H4 selectively binds to subunit 2 of the spike(S)protein,as shown by a biochemical binding assay,surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino *** acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S ***,histones enhance cell-cell ***,treatment with an inhibitor of NETosis,histone H3 or H4,or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse *** findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.

关键词： COVID-19 SARS-CoV-2 neutrophil extracellular traps histones sialic acid

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

浅埋煤层过沟开采地表裂缝动态发育规律研究

煤矿安全 2023年第8期54卷 136-142页

作者：姜钰泉孙学阳姚星王志杰贾少杰安宁陕西煤田地质勘查研究院有限公司陕西西安710021 西安科技大学地质与环境学院陕西西安710054 深圳市易图资讯股份有限公司广东深圳518000 甘肃工程地质研究院甘肃兰州730000

为研究煤层在过沟开采时地表裂缝在不同位置的动态演化规律,以陕北某矿14210工作面为原型,运用相似材料模拟实验并结合VIC-3D系统研究了地表裂缝的发育特征。研究结果显示:沟谷处地表裂缝发育宽度先增大再急速减少最终闭合;左侧坡面与... 详细信息

为研究煤层在过沟开采时地表裂缝在不同位置的动态演化规律,以陕北某矿14210工作面为原型,运用相似材料模拟实验并结合VIC-3D系统研究了地表裂缝的发育特征。研究结果显示:沟谷处地表裂缝发育宽度先增大再急速减少最终闭合;左侧坡面与右侧坡面地表裂缝发育宽度先增大后小幅减少再趋于稳定;根据其发育位置与应变变化将地表裂缝分为左侧坡面张拉地表裂缝、沟谷挤压地表裂缝及右侧坡面张拉地表裂缝3类。通过对14210工作面过沟开采进行安全性预测可知:在过沟开采期间导致乌兰不拉沟泉水涌入工作面的因素大致分为裂缝宽度、裂缝分布密度、沟中水位、工作面推进速度4个因素。

关键词：过沟开采地表裂缝 VIC-3D系统动态演化规律覆岩应变

On-orbit equalization of the electromagnetic calorimeter of the Alpha Magnetic Spectrometer

在线全文

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2021年第3期5卷 430-433页

作者： Ze-Tong sun jia-Yu Hu Zhi-Cheng Tang Cheng Zhang Feng-Ze Zhang Shang-Lin Li Mei-Jun Liang Zu-Hao Li Guo-Ming Chen He-Sheng Chen Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Purpose The Alpha Magnetic Spectrometer(AMS-02)will continuously collect data for the lifetime of the International Space Station(ISS).On-orbit equalization must be performed to ensure the accuracy of the AMS energy measurement(~1%)by the electromagnetic calorimeter(ECAL).Methods The equalization is performed using the most probable value(MPV)of the cosmic-ray proton minimum ionizing particle(MIP).Kalman filter technique is used to improve the *** The precision of the equalization with proton MIP is(7.206±0.003)%and improved to(2.388±0.002)%after the Kalman *** the toy Monte Carlo(MC)simulation,the error of the energy reconstruction is about 1.4%and 0.5%due to the 7.2%and 2.4%equalization accuracy,*** About 1.4%error due to~7%equalization precision does not match the AMS *** the improvement from the Kalman filter,the energy reconstruction error from the equalization is reduced to 0.5%,which can fulfill the AMS requirement.

关键词： Equalization Electromagnetic calorimeter Kalman filter Proton MIP Energy resolution

基于主成分分析法的南四湖流域水污染物排放水平空间布局分析

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

科学与管理 2013年第6期33卷 88-90页

作者：孙灵文闫中晓邵波贾永飞山东省科技发展战略研究所济南250014 山东省科学院科学决策支持重点实验室济南250014 山东师范大学人口.资源与环境学院济南250014

本文基于2007年第一次全国污染源普查数据,运用主成分分析法,对南四湖流域山东省境内的28个县市区行政单元的水污染物排放水平进行了综合评价,结果显示:滕州市的污染物排放水平明显高于流域内的其他区域,济宁市中区、邹城市、菏泽市区... 详细信息

本文基于2007年第一次全国污染源普查数据,运用主成分分析法,对南四湖流域山东省境内的28个县市区行政单元的水污染物排放水平进行了综合评价,结果显示:滕州市的污染物排放水平明显高于流域内的其他区域,济宁市中区、邹城市、菏泽市区、曹县的污染物排放水平也较高。因此这五个县市是今后南四湖流域治污的重点。

关键词：主成分分析南四湖流域污染物排放空间布局

在线全文

学校读者我要写书评

暂无评论

酶促有机固体废弃物资源化技术研究进展

环境工程 2023年第S2期41卷 1247-1253页

作者：郑义冯梓薇周凯云贾凯雪孙宝茹魏雨泉徐道青李季中国农业大学资源与环境学院北京100193 中国农业大学有机循环研究院(苏州) 江苏苏州215100 安徽省农业科学院棉花研究所合肥230001

我国有机固体废物产生量逐年增加,已引起广泛关注,利用生物法处理可以有效实现有机固体废弃物资源化利用,但生物处理过程效率低,需要联用预处理技术来提升有机固体废弃物资源化过程中的效率。酶处理可以使有机固体废弃物中难降解有机质... 详细信息

我国有机固体废物产生量逐年增加,已引起广泛关注,利用生物法处理可以有效实现有机固体废弃物资源化利用,但生物处理过程效率低,需要联用预处理技术来提升有机固体废弃物资源化过程中的效率。酶处理可以使有机固体废弃物中难降解有机质快速转化为小分子有机质,提升有机固体废弃物资源化效率。首先讨论了纤维素酶和脂肪酶2种关键酶的在有机固体废弃物降解过程中的作用机理;重点汇总了纤维素酶和脂肪酶在好氧堆肥和厌氧发酵资源化过程中的应用;进一步总结了酶的高效技术应用,以期实现纤维素酶和脂肪酶高效制备和固定化;最后对酶在固体废物处理领域的应用进行展望,推动酶促有机固体废弃物资源化技术的发展。

关键词：有机固体废弃物纤维素酶脂肪酶酶固定化