检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

利用ICT算法计算变压器绕组中的VFTO

高电压技术 2008年第8期34卷 1650-1655页

作者：吕应刚梁贵书董华英华北电力大学电气工程学院保定071003

为研究特快速暂态过电压(VFTO)对变压器的影响并解决大型电力变压器建模时矩阵阶数过大的问题,以匝为单元建立了变压器绕组多导体传输线(MTL)模型,并利用积分相合变换(ICT)的阶数缩减算法直接对电报方程进行求解,避免了对传输线时空离... 详细信息

为研究特快速暂态过电压(VFTO)对变压器的影响并解决大型电力变压器建模时矩阵阶数过大的问题,以匝为单元建立了变压器绕组多导体传输线(MTL)模型,并利用积分相合变换(ICT)的阶数缩减算法直接对电报方程进行求解,避免了对传输线时空离散造成矩阵阶数过大的问题,有效地提高了计算效率并且保证了降阶系统的无源性。仿真与实验结果证明该法正确可行。

关键词：变压器绕组特快速暂态过电压多导体传输线阶数缩减积分相合变换希尔伯特空间

Detection of Repair of the Zone of Calcified Cartilage with Osteoarthritis through Mesenchymal Stem Cells by Ultrashort Echo Time Magnetic Resonance Imaging

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2018年第9期131卷 1092-1098页

作者： Quan Zhou Shao-Lin Li Ya-Jun Ma Vicki de Tal Wei Li ying-hua Zhao Department of Radiology Third Affiliated Hospital of Southern Medical University (Academy of Orthopedics Guangdong Province) Guangzhou Guangdong 510630 China Department of Medical Imaging The Fifth Affiliated Hospital of Sun Yat-sen University Zhuhai Guangdong 519000 China Department of Radiology University of California San Diego CA 92103-8226 USA

Objective：Currently,magnetic resonance imaging （MRI） is the most commonly used imaging modality for observing the growth and development of mesenchymal stem cells （MSCs） after in vivo transplantation to treat osteoarthritis （OA）.However,it is a challenge to accurately monitor the treatment effects of MSCs in the zone of calcified cartilage （ZCC） with *** is especially true in the physiological and biochemical views that are not accurately detected by MRI contrast *** contrast,ultrashort time echo （UTE） MRI has been shown to be sensitive to the presence of the ZCC,creating the potential for more effectively observing the repair of the ZCC in OA by MSCs.A special focus is given to the outlook of the use ofUTE MRI to detect repair of the ZCC with OA through *** limitations of the current techniques for clinical applications and future directions are also *** Sources：Using the combined keywords：＂osteoarthritis＂,＂mesenchymal stem cells＂,＂calcified cartilage＂,and ＂magnetic resonance imaging＂,the PubMed/MEDLINE literature search was conducted up to June 1,*** Selection：A total of 132 published articles were initially identified *** the 132 articles,48 articles were selected after further detailed *** study referred to all the important English literature in ***：In contrast,UTE MRI has been shown to be sensitive to the presence of the ZCC,creating the potential for more effectively observing the repair of the ZCC in OA by ***：The current studies showed that the ZCC could be described in terms of its histomorphology and biochemistry by UTE *** prospected that UTE MRI has been shown the potential for more effectively observing the repair of the ZCC in OA by MSCs in vivo.

关键词： Magnetic Resonance Imaging Mesenchymal Stem Cells Osteoarthritis Ultrashort Echo Time Zone of Calcified Cartilage

在线全文

学校读者我要写书评

暂无评论

轮辐设计特征参数对整车气动特性的影响

吉林大学学报（工学版） 2021年第1期51卷 107-113页

作者：苏畅韩颖张英朝苗振华吉林大学汽车仿真与控制国家重点实验室长春130022

为探究车轮轮辐偏移距离和轮辐曲率对整车气动阻力系数的影响,以改进的MIRA模型为研究对象,在Fluent软件中首先分别探究不同轮辐偏移距离及不同曲率与整车气动阻力系数的关系,分析不同工况减阻及增阻原因;之后将各工况进行组合,探究各... 详细信息

为探究车轮轮辐偏移距离和轮辐曲率对整车气动阻力系数的影响,以改进的MIRA模型为研究对象,在Fluent软件中首先分别探究不同轮辐偏移距离及不同曲率与整车气动阻力系数的关系,分析不同工况减阻及增阻原因;之后将各工况进行组合,探究各组合工况对整车气动阻力系数的影响。仿真结果表明:较小的轮辐偏移距离有利于整车气动阻力系数的降低,且当轮辐偏移距离为10 mm时,整车气动阻力系数最小,仅为0.2514,与基础工况相比减阻率达5.56%;但轮辐曲率的增大会使整车气动阻力系数增大。

关键词：空气动力学轮辐偏移距离轮辐曲率气动阻力系数数值模拟

脉冲抽运光啁啾对全光纤量子关联光子对纯度的影响

在线全文

学校读者我要写书评

暂无评论

物理学报 2013年第16期62卷 174-178页

作者：王堃崔亮张秀婷李小英天津大学精密仪器与光电子工程学院光电信息技术教育部重点实验室天津300072

信号与闲置光子波长均为1550nm通信波段的全光纤关联光子对源,具有低成本以及可与现有光纤网络低损耗连接的特点.进一步优化其纯度,将有助于提高这种量子光源的实用化程度.当抽运脉冲光在光纤中传输时,由于色散和Kerr非线性效应的影响,... 详细信息

信号与闲置光子波长均为1550nm通信波段的全光纤关联光子对源,具有低成本以及可与现有光纤网络低损耗连接的特点.进一步优化其纯度,将有助于提高这种量子光源的实用化程度.当抽运脉冲光在光纤中传输时,由于色散和Kerr非线性效应的影响,会不可避免地引入啁啾.本文利用脉冲激光抽运零色散位移光纤,研究了抽运光啁啾对关联光子对纯度的影响.结果表明,通信波段小失谐关联光子对的纯度随啁啾的增大而下降.若采用变换极限的锁模激光为抽运源,将有助于抑制Raman散射对自发四波混频的影响,提高光子对的纯度.

关键词：关联光子对光纤自发四波混频啁啾

pH响应型P(HEMA/MAA)纳米微凝胶分散液的凝胶化行为和流变性能

在线全文

学校读者我要写书评

暂无评论

物理化学学报 2011年第8期27卷 1919-1925页

作者：申迎华刘慧敏李国卿翟志国树学峰台秀梅太原理工大学化学化工学院太原030024 太原理工大学应用力学与生物医学工程研究所太原030024 中国日用化学工业研究院太原030001

制备了在修复受损组织方面有应用潜能的纳米级聚(甲基丙烯酸羟乙酯/甲基丙烯酸)(P(HEMA/MAA))微凝胶;采用试管倒转法对不同pH值和浓度的P(HEMA/MAA)微凝胶分散液的凝胶化相转变行为进行了研究;借助椎板流变仪考察了低浓度和高浓度微凝... 详细信息

制备了在修复受损组织方面有应用潜能的纳米级聚(甲基丙烯酸羟乙酯/甲基丙烯酸)(P(HEMA/MAA))微凝胶;采用试管倒转法对不同pH值和浓度的P(HEMA/MAA)微凝胶分散液的凝胶化相转变行为进行了研究;借助椎板流变仪考察了低浓度和高浓度微凝胶分散液的流变性能,并对pH触发物理凝胶化相转变机理进行了推测.结果表明:在生理pH值环境下,一定浓度的P(HEMA/MAA)微凝胶分散液可以发生凝胶化相转变形成凝胶态,pH=7时,HEMA/MAA进料摩尔比为8/2的微凝胶分散液凝胶化后得到的凝胶力学性能最佳,最大弹性模量(G')可达7.58×103Pa;P(HEMA/MAA)微凝胶颗粒在不同条件下具有不同的溶胀效果,导致低浓度分散液的表观粘度发生相应的变化,并由此推测出微凝胶颗粒的溶胀过程由外及内,分为三个阶段;高浓度微凝胶分散液发生凝胶化相转变主要是由颗粒间或颗粒与分散介质间形成的空间静电稳定作用和氢键共同作用引起的.

关键词：凝胶化 P(HEMA/MAA)微凝胶 pH响应性分散液浓度弹性模量

Preparation of Fe_3O_4/PS Magnetic Particles by Dispersion Polymerization

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第2期8卷 183-184页

作者： Xiao Bin DING hua Zhong SUN Guo Xiang WAN ying Yan JIANG(a Chengdu Institute of Organic Chemistry, Chinese Academy of Science, Chengdu 610041b Beijing Institute of Chemistry,Chinase Academy of science , BeiJing 100080) CHINESE ACAD SCI CHENGDU INST ORGAN CHEMCHENGDU 610041PEOPLES R CHINA CHINESE ACAD SCI BEIJING INST CHEMBEIJING 100080PEOPLES R CHINA

Fe_3O_4/PS magnetic particles with core/shell structure has been prepared in the presence of Fe3O4 magnetic fluid in ethanol/water *** particles with diameter size range from 5. 54 t0 187. 32 μm were obtained by different reaction *** parameters such as ethanol, PEG and monomer which affect particle size diameter and size distribution are discussed briefly in this paper.

关键词： PS Preparation of Fe3O4/PS Magnetic Particles by Dispersion Polymerization Fe

在线全文

学校读者我要写书评

暂无评论

制约保险产品创新的因素及其对策

特区经济 2005年第1期 173-174页

作者：沈秀肖莺西南财经大学

一、制约保险产品创新的因素1.保险产品自身的特殊性制约保险产品的创新保险产品创新容易产生新的市场风险.保险产品是一种不能预见,不能用五官直接接触到的特殊消费.

关键词：保险产品创新购买制约信誉客户市场风险使用价值保险人预见索赔

Design and implementation of a software architecture for 3D-DDA

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第9期58卷 1604-1608页

作者： CHENG XiaoLong XIAO Jun MIAO QingHai WANG ying College of Engineering & Information Technology University of Chinese Academy of Sciences

The three-dimensional discontinuous deformation analysis(3D-DDA) is a promising numerical method for both static and dynamic analyses of rock systems. Lacking mature software, its popularity is far behind its ability. To address this problem, this paper presents a new software architecture from a software engineering viewpoint. Based on 3D-DDA characteristics, the implementation of the proposed architecture has the following merits. Firstly, the software architecture separates data, computing, visualization, and signal control into individual modules. Secondly, data storage and parallel access are fully considered for different conditions. Thirdly, an open computing framework is provided which supports most numerical computing methods; common tools for equation solving and parallel computing are provided for further development. Fourthly, efficient visualization functions are provided by integrating a variety of visualization algorithms. A user-friendly graphical user interface is designed to improve the user experience. Finally, through a set of examples, the software is verified against both analytical solutions and the original code by Dr. Shi Gen hua.

关键词： 3D-DDA software architecture 3D-DDA data structure open computing framework efficient visualization

Studies on the Redox Properties of Undecatungstotitanates Containing One Kind of Transition Metal

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 1995年第2期11卷 158-162页

作者： LIU Jing-fu,WANG ying,WANG Fu-quan and YANG Qi-hua (Department of Chemistry,Northeast Normal University,Changchun,130024)WANG Wei (Department of Applied Chemistry,Dalian Railway Institute,Dalian,116022) NE NORMAL UNIV DEPT CHEMCHANGCHUN 130024PEOPLES R CHINA DALIAN INST RAILWAY TECHNOL DEPT APPL CHEMDALIAN 116022PEOPLES R CHINA

Some monosubstituted Keggin or Dawson anions nave been reporten by Hill to be "remarkably effective" catalysts for the epoxidation of alkenes, Hill, Finke and Neumann reported respectively that the transition metal monosubstituted heteropolyanions [PW;O;M（H;O）]";, [P;W;O;M（L）]"- and [SiW;O;Ru（H;O）];have an ability to catalyze the epoxidation of alkenes. And the undecatungstotitanates with one kind of transition metal have

关键词： Undecatungstotitanate Transition metal Redox property Epoxida-tion reaction of alkenes