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Topological Structure and Topological Tensor Current of Gauss-Bonnet-Chern Theorem

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Communications in Theoretical Physics 2006年第5期45卷 793-798页

作者： DUAN Yi-Shi WU Shao-Feng zhang peng-ming Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China Department of Mathematics Lanzhou University Lanzhou 730000 China

We offer an intrinsic theoretical framework to reveal the inner relationships among three theories for Euler characteristic number, including Gauss Bonnet-Chern theorem, Hop-Poincaré theorem and Morse theory. Moreover, we consider the Gauss Bonnet-Chern （GBC） form imbedded in arbitrary higher-dimensional manifold, which suggests a Hodge dual tensor current. We show the brane structure inherent in the GBC tensor current and obtain the generalized Nambu action for the multi branes with quantized topological charge.

关键词： Gauss-Bonnet-Chern theorem topological tensor current branes

New Type of Conserved Quantities of Lie Symmetry for Nonholonomic Mechanical Systems in Phase Space

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Communications in Theoretical Physics 2009年第12期52卷 977-980页

作者： PANG Ting FANG Jian-Hui LIN peng zhang ming-Jiang LU Kai College of Physics Science and Technology China University of Petroleum Dongying 257061 China

The new types of conserved quantities, which are directly induced by Lie symmetry of nonholonomie mechanical systems in phase space, are studied. Firstly, the criterion of the weak Lie symmetry and the strong Lie symmetry are given. Secondly, the conditions of existence of the new type of conserved quantities induced by the weak Lie symmetry and the strong Lie symmetry directly are obtained, and their form is presented. Finaily, an Appell-Hamel example is discussed to further illustrate the applications of the results.

关键词： Lie symmetry conserved quantity nonholonomic mechanical system phase space

Glucose,cellobiose,lactose and raffinose used as chiral stationary phases in HPLC

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Chinese Chemical Letters 2008年第10期19卷 1248-1251页

作者： Jian Yu Wang Feng Zhao Mei zhang Ya peng Li ming Yuan Department of Chemistry Yunnan Normal University Kunming 650092 China

This paper presents the enantioseparation using glucose, cellobiose, lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC. Surprisingly, they also possess high enantioseparation selectivity, may be used in normal-phase and reversed- phase mode, and there is a big chiral discriminating complementary. This work indicates that oligosaccharides could soon become very attractive as a new class of chiral stationary phase for HPLC.

关键词： Oligosaccharides Chiral stationary phase HPLC

Utilising ductus venosus Doppler waveform and four-chamber view to screen for foetal cardiac malformation in early second trimester of pregnancy

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Chinese Medical Journal 2005年第21期118卷 1791-1796页

作者： ZHOU Qi-chang zhang Jing zhang ming peng Qing-hai CAO Dan-ming WANG Xiao-yan Department of Uhrasonography Second Xiangya Hospital of Central South University Changsha 410011 China

Background Foetal echocardiography has become a diagnostic method to detect foetal congenital heart disease with high probability. However, it is not only time consuming and but also difficult to visualize outflow tract of foetus early in the second trimester of pregnancy, even for an experienced obstetric uhrasonographer. Recently, many methods for screening foetal cardiac anomalies were explored, but much more work is needed to develop an effective and suitable screening method. The aim of this study was to investigate the clinical significance of utilising the ductus venosus （DV） Doppler examination and the four-chamber view of heart to screen for foetal cardiac malformation in early second trimester of pregnancy. Methods Heart and DV of 401 consecutive foetuses in early second trimester （12^＋1- 17^ ＋6 weeks） in high risk pregnancies were examined with Acuson 128 xp/10 or Sequoia 512 ultrasound diagnostic systems. Absent or reversed flow during atrial contraction （A-wave） in the DV was defined as sufficiently abnormal to screen for foetal cardiac malformations. The foetal echocardiographic diagnosis was confirmed by postnatal echocardiography （or postmortem）. The sensitivities of screening tests were compared among the three methods： DV Doppler examination, four-chamber view alone, and the combination of both *** Satisfactory examinations were obtained in 383/401 foetuses （95%）. Thirty foetuses with cardiac abnormalities were confirmed by neonatal echocardiography （ or postmortem ）. The sensitivity of DV Doppler examination or four-chamber view alone is 63 % （19/30） and 60 % （ 18/30）, respectively. The sensitivity of combining information, DV Doppler flow waveform and four-chamber view, to screen for foetal cardiac malformation is 83% （25/30） and significantly better than that of either DV Doppler flow waveform or four chamber view alone （ P 〈 0. 05 ）. Conclusion Doppler flow waveform of DV can be used to screen for foetal cardiac malformation earl

关键词： prenatal diagnosis ultrasonography foetus ductus venosus congenital heart disease

Lung transplantation in a Chinese single center： 7 years of experience

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Chinese Medical Journal 2011年第7期124卷 978-982页

作者： HE Wen-xin JIANG Ge-ning DING Jia-an GAO Wen ZHU Yu-ming ZHOU Xiao CHEN Chang WANG Hao FAN Jiang zhang peng LIU ming Department of Thoracic Surgery Shanghai Pulmonary HospitalTongji University School of Medicine Shanghai Key Laboratoryof Organ Transplantation Shanghai 200433 China

Background Lung transplantation （LT） is a viable option for patients with end-stage lung diseases, but in China, the supply is limited, and the experience with LT is rare too. This study aimed to evaluate the surviv... 详细信息

关键词： lung transplantation China survival complications

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高速列车牵引变压器振动响应容限有限元分析

交通运输工程学报 2016年第5期16卷 42-48页

作者：于金朋宋青鹏张明远张继旺刘小霞张立民西南交通大学牵引动力国家重点实验室四川成都610031 中车唐山机车车辆有限公司河北唐山063035

为保证高速列车车下设备结构的安全性,基于振动响应容限仿真计算方法和米塞斯应力屈服准则,运用有限元仿真模型对线性和非线性悬挂刚度下高速列车牵引变压器的振动响应容限进行研究。对牵引变压器沿纵向、横向、垂向同时加载,得到响应... 详细信息

为保证高速列车车下设备结构的安全性,基于振动响应容限仿真计算方法和米塞斯应力屈服准则,运用有限元仿真模型对线性和非线性悬挂刚度下高速列车牵引变压器的振动响应容限进行研究。对牵引变压器沿纵向、横向、垂向同时加载,得到响应应力最大的危险节点。对牵引变压器分别沿纵向、横向、垂向进行加载,得到危险节点的6个应力分量和不同方向振幅的关系,并基于叠加原理,得到纵向、横向、垂向同时加载下危险节点应力分量和不同方向振幅的关系。基于求得的米塞斯应力函数与米塞斯应力屈服准则,得到振动响应容限。分析结果表明:基于叠加原理,可以运用MATLAB替代ANSYS对线性悬挂刚度下的振动响应容限进行仿真计算;线性与非线性悬挂刚度下的振动响应容限曲面间存在一条垂向位移等值曲线,当横向位移与纵向位移组成的坐标点位于垂向位移等值曲线在平面内的投影线以下时,线性悬挂刚度下垂向位移的振动响应容限比相应非线性悬挂刚度下的振动响应容限大,当横向位移与纵向位移组成的坐标点位于垂向位移等值曲线在平面内的投影线以上时,线性悬挂刚度下垂向位移的振动响应容限比相应非线性悬挂刚度下的振动响应容限小。

关键词：高速列车牵引变压器振动响应容限线性悬挂刚度非线性悬挂刚度

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主动磁悬浮轴承的滑模自抗扰解耦控制

电机与控制学报 2021年第7期25卷 129-138页

作者：李冰林曾励张鹏铭竺志大南京林业大学汽车与交通工程学院南京210037 扬州大学机械工程学院江苏扬州225009 浙江精功科技股份有限公司浙江绍兴312030

针对磁悬浮轴承系统各径向自由度之间存在的耦合关系,特别是转子高速时的陀螺效应耦合,提出了一种基于滑模自抗扰解耦控制的方法。首先建立了考虑耦合效应的系统模型,利用扩张状态观测器对系统的内外扰动进行估计和补偿,把多变量耦合系... 详细信息

针对磁悬浮轴承系统各径向自由度之间存在的耦合关系,特别是转子高速时的陀螺效应耦合,提出了一种基于滑模自抗扰解耦控制的方法。首先建立了考虑耦合效应的系统模型,利用扩张状态观测器对系统的内外扰动进行估计和补偿,把多变量耦合系统解耦成4个单自由度的二阶串联积分型子系统。为保证系统的快速动态响应,将滑模控制引入到非线性状态误差反馈控制律中,设计了各自由度的滑模自抗扰控制器,并利用Lyapunov理论证明了控制系统的稳定性。通过抗干扰和信号跟踪试验仿真,结果表明,所设计的滑模自抗扰控制器实现了对磁悬浮轴承各自由度的解耦控制,响应快,能对设定信号进行跟踪,抗干扰能力强,同时解决了磁悬浮轴承高转速运行下的陀螺效应对控制的影响,能适用于纺纱机械转杯的高速场合。

关键词：磁悬浮轴承自抗扰控制滑模控制解耦扩张状态观测器

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巴彦高勒矿井集装箱辅助运输系统研究

煤炭工程 2021年第4期53卷 16-19页

作者：张明鹏曹连民内蒙古黄陶勒盖煤炭有限责任公司巴彦高勒煤矿内蒙古鄂尔多斯017300 山东科技大学机械电子工程学院山东青岛266590

针对巴彦高勒矿井辅助运输系统冗长环节多、运输效率低、可靠性和安全性不高等问题,通过对巴彦高勒矿井井上井下辅助运输工况进行研究,对比分析了不同换装模式下的工作效率,结果表明:采用"集装箱换装模式"的方法,可以使矿井辅助运输效... 详细信息

针对巴彦高勒矿井辅助运输系统冗长环节多、运输效率低、可靠性和安全性不高等问题,通过对巴彦高勒矿井井上井下辅助运输工况进行研究,对比分析了不同换装模式下的工作效率,结果表明:采用"集装箱换装模式"的方法,可以使矿井辅助运输效率得到大幅提升,依靠升级改进后的运输设备对于提高煤矿的产量、减低生产成本、提高辅助运输水平具有重要意义。

关键词：煤矿矿井辅助运输集装箱换装模式

基于MATLAB/PDEtool的轴对称场分析

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铁道学报 2005年第1期27卷 124-127页

作者：张友鹏田铭兴兰州交通大学信息与电气工程学院甘肃兰州730070

MATLAB/PDEtool是非常优秀的二维偏微分有限元求解软件,具有像静电场、静磁场和工频交流电磁场等专业模式,但这些专业模式不能直接用于柱坐标系表示的轴对称场的求解分析。文章推导出了正交坐标系中的泊松方程,并通过柱坐标系中轴对称... 详细信息

MATLAB/PDEtool是非常优秀的二维偏微分有限元求解软件,具有像静电场、静磁场和工频交流电磁场等专业模式,但这些专业模式不能直接用于柱坐标系表示的轴对称场的求解分析。文章推导出了正交坐标系中的泊松方程,并通过柱坐标系中轴对称场的方程形式和直角坐标系中标准二维椭圆型偏微分方程形式的比较,得到了他们坐标之间、系数之间的对应关系,据此用MATLAB/PDEtool对轴对称场进行了求解分析,结果说明本文的方法是有效的。

关键词：平行平面场轴对称场静磁场 MATALAB