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DC Traction Power Supply System Based on Modular Multilevel Converter Suitable for Energy Feeding and De-icing

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 649-659页

作者： Lingxi hou Shuqing Zhang Yingdong Wei Xiaoqian Li Qirong Jiang Mingrui Li Weirui Li department of Electrical Engineering Tsinghua UniversityBeijing 100084China

A novel DC traction power supply system suitable for energy feeding and de-icing is proposed in this paper for an urban rail transit catenary on the basis of the full bridge submodule (FBSM) modular multilevel converter (MMC). The FBSM-MMC is a novel type of voltage source converter (VSC) and can directly control the output DC voltage and conduct bipolar currents, thus flexibly controlling the power flow of the urban rail transit catenary. The proposed topology can overcome the inherent disadvantages of the output voltage drop in the diode rectifier units, increase the power supply distance and reduce the number of traction substations. The flexible DC technology can coordinate multiple FBSM-MMCs in a wide area and jointly complete the bidirectional control of catenary power flow during the operation of the electric locomotive, so as to realize the local consumption and optimal utilization of the recovered braking energy of the train. In addition, the FBSM-MMCs can also adjust the output current when the locomotive is out of service to prevent the catenary from icing in winter. The working modes of the proposed topology are illustrated in detail and the control strategy is specially designed for normal locomotive operations and catenary de-icing. Simulation cases conducted by PSCAD/EMTDC validate the proposed topology and its control strategy.

关键词： DC traction power supply system de-icing for catenary energy feeding modular multilevel converter based on full-bridge submodules(FBSM-MMC) urban rail transit

Microfluidic-based isolation of circulating tumor cells with high-efficiency and high-purity

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Chinese Chemical Letters 2024年第8期35卷 101-111页

作者： Feng Wu Xuemin Kong Yixuan Liu Shuli Wang Zhong Chen Xu hou Fujian Engineering Research Center for Solid-State Lighting Department of Electronic ScienceSchool of Electronic Science and EngineeringXiamen UniversityXiamen 361005China College of Physics and New Energy Xuzhou University of TechnologyXuzhou 221018China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of Physical Science and Technology Xiamen UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361102China

The isolation of circulating tumor cells(CTCs)from complex biological samples is of paramount signifi-cance for advancing cancer diagnosis,prognosis,and ***,the low concentration of CTCs and nonspecific adhesion of white blood cells(WBCs)present challenges that hinder the efficiency and purity of captured ***-based strategies utilize precise fluid control at the micron level to incorporate specific micro/nanostructures or recognition molecules,enabling effective CTCs ***,by employing surface modification designs that exhibit exceptional anti-adhesion properties against WBCs,the purity of isolated CTCs can be further *** review offers an in-depth explo-ration of recent advancements,challenges,and opportunities associated with microfluidic-based CTCs iso-lation from biological ***,we will comprehensively introduce the microfluidic-based strate-gies for achieving high-efficiency CTCs isolation,which includes the morphological design of microchan-nels for physical force-based CTCs isolation and the specific modification of microchannel surfaces for affinity-based CTCs ***,a review of recent research advances in microfluidic-based high-purity CTCs isolation is presented,focusing on strategies that decrease the nonspecific adhesion of WBCs through surface micro-/nanostructure construction or chemical and biological ***,we will summarize the article by providing the prospective opportunities and challenges for the future development of microfluidic-based CTCs isolation.

关键词： Microfluidics Isolation Circulating tumor cells High-efficiency High-purity

Minimal Rank Preserving Additive Mappings on Upper Triangular Matrices

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Journal of Mathematical Research and Exposition 2011年第6期31卷 951-964页

作者： Yu GUO1,2,3,jin Chuan hou2,3 1.department of mathematics,Shanxi Datong university,Shanxi 037009,P.R.china 2.department of mathematics,Shanxi university,Shanxi 030006,P.R.china 3.department of mathematics,Taiyuan university of Technology,Shanxi 030024,P.R.china department of mathematics Shanxi Datong University department of mathematics Shanxi University department of mathematics Taiyuan University of Technology

The additive mappings that preserve the minimal rank on the algebra of all n × n upper triangular matrices over a field of characteristic 0 are characterized.

关键词： rank minimal rank upper triangular matrices additive mappings

Software structure evaluation based on the interaction and encapsulation of methods

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Science china(Information Sciences) 2012年第12期55卷 2816-2825页

作者： ZHENG QingHua 1,2,OU ZhiJiang 1,2,LIU Ting 1,YANG ZiJiang 3,hou YuQiao 1,2 & ZHENG Chao 1,2.1.MOE Key Laboratory for Intelligent Networks and Network Security,Xi'an Jiaotong university,Xian 710049,china 2 Shaanxi Key Laboratory of Satellite-terrestrial Network Technology R&D,Xi'an Jiaotong university,Xian 710049,china 3 department of Computer Science,Western Michigan university,Michigan,USA 1. MOE Key Laboratory for Intelligent Networks and Network Security Xi’an Jiaotong University Xian 710049 China2. Shaanxi Key Laboratory of Satellite-terrestrial Network Technology R&D Xi’an Jiaotong University Xian 710049 China3. Department of Computer Science Western Michigan University Michigan USA

Software structure is the most important factor affecting the quality of a *** evaluation of software structure is a foundational technique for software ***,the traditional evaluation criteria,such as "high cohesion and low coupling",are no longer appropriate for the new web applications,which are designed with a hierarchical framework.A novel approach is proposed in this paper to evaluate software quality based on the interaction and encapsulation of *** particular,two criteria for high quality software,the functional and hierarchical structure,are proposed to support widely used web *** cohesion and coupling and layer matching ratios between methods within a software package are calculated to determine whether the package is well implemented in terms of functional or hierarchical *** approach enables us to quantify the quality of a software system according to the structural types of its *** were carried out on 18 versions of Struts and six open-source software *** evaluation concurs with the intuition that minor upgrades,aimed at fixing bugs and adding minor functionality quickly,reduce software quality,whereas major upgrades,which normally clean up messy code and re-construct the software,improve software quality.

关键词： software structure evaluation method interaction method encapsulation functional structure hierarchical structure

On critical values concerning the evolution of the long period families

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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 494-500页

作者： Xi-Yun hou1,21 Astronomy department, Nanjing university, Nanjing 210093, china 2 Institute of Space Environment and Astronautics, Nanjing university, Nanjing 210093, china Astronomy department Nanjing University Nanjing 210093 China Institute of Space Environment and Astronautics Nanjing University Nanjing 210093 China

In a previous paper, we proposed another special critical value concerning the evolution of the long period family around the equilateral equilibrium points, besides the two values given by Henrard. Are there any other special critical values？ After studying the stability curves of the long period family carefully, we gave a negative answer. During the study, we found an interesting family of periodic orbits which we called the homo family. We studied the evolution of this family following the increase of μ. With these findings, we were able to explain the origin of the four branches of periodic families emanating from L4 and the stability results of the equilateral equilibrium points.

关键词： celestial mechanics

Microscopic nonlinear optical activities and ultrafast carrier dynamics in layered AgInP_(2)S_(6)

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Photonics Research 2024年第4期12卷 691-700页

作者： zixin WANG NINGNING DONG YU MAO CHENDUAN CHEN XIN CHEN CHANG XU ZhouYUAN YAN JUN WANG Aerospace Laser Technology and Systems department CAS Key Laboratory of Materials for High-Power LaserShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Ultra-intense Laser Science(CEULS) State Key Laboratory of High Field Laser PhysicsShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China

Since the emergence of graphene, transition metal dichalcogenides, and black phosphorus, two-dimensional materials have attracted significant attention and have driven the development of fundamental physics and optoelectronic devices. Metal phosphorus trichalcogenides(MPX3), due to their large bandgap of 1.3–3.5 eV, enable the extension of optoelectronic applications to visible and ultraviolet(UV) wavelengths.

关键词： nonlinear ultraviolet phosphorus

内外水力交互下浅埋带压盾构隧道水土压力计算模型

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岩土工程学报 2024年第8期46卷 1685-1694页

作者：谢家冲黄昕金国龙张子新同济大学土木工程学院地下建筑与工程系上海200092 新疆大学建筑工程学院新疆乌鲁木齐830047 同济大学岩土及地下工程教育部重点实验室上海200092 中船第九设计研究院工程有限公司上海200063 加泰罗尼亚理工大学土木与环境工程学院巴塞罗那08034

针对浅埋有压盾构隧道内外水力交互渗流下引起的松动水土压力变化,基于修正镜像法获得了考虑内水压的地层渗流场分布与水力梯度。随后基于考虑松动区内部应力分布的修正Terzaghi公式给出了考虑隧道内水压下的松动区任意位置的水土压力解... 详细信息

针对浅埋有压盾构隧道内外水力交互渗流下引起的松动水土压力变化,基于修正镜像法获得了考虑内水压的地层渗流场分布与水力梯度。随后基于考虑松动区内部应力分布的修正Terzaghi公式给出了考虑隧道内水压下的松动区任意位置的水土压力解,并与数值模拟结果进行了对比验证。主要结论如下:采用圆弧拱和抛物线拱的主应力轨迹线能够有效描述隧顶松动区应力分布情况;当地层渗透系数与衬砌渗透系数比值小于1000时,内压水头大小对水土压力的影响显著;内压水头的增加将减小松动区有效应力,引起上覆土体卸载,同时引起隧顶松动区总应力增大,表明该范围内孔隙水压的增长对水土压力的变化占据主导作用;5参数正交分析结果的线性回归分析结果表明隧道埋深和半径对土压力有显著的正向影响,土体摩擦角和黏聚力均表现为负向影响。在相对低渗透地层条件下,内压水头对隧顶有效应力和总应力分别表现为显著的负向和正向影响。

关键词：带压盾构隧道衬砌渗漏内水外渗松动土压力土拱镜像法

COUPLED SOLUTION FOR ANISOTROPIC PIEZOELECTRIC MATERIALS WITH CRACKS

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Acta Mechanica Solida Sinica 1999年第1期12卷 83-90页

作者： hou Mishan (department of Mechanical Engineering,university of Petroleum,Dongying 257062,china) department of Mechanical Engineering University of Petroleum Dongying 257062 China

The coupled elastic and electric fields for anisotropic piezoelectric materials with electrically permeable cracks are analyzed by using Stroh formula in anisotropic elasticity. It is shown from the solution that the tangent component of the electric field strength and the normal component of the electric displacement along the faces of cracks are all constants, and the electric field intensity and electric displacement have the singularity of type (1/2) at the crack tip. The energy release rate for crack propagation depends on both the stress intensity factor and material constants. The electric field intensity and electric displacement inside electrically permeable cracks are all constants.

关键词： piezoelectric material crack stress intensify factor energy release rate

Exploration of pathogenic microorganism within the small intestine of necrotizing enterocolitis

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World Journal of Pediatrics 2024年第2期20卷 165-172页

作者： Yan Wang Kun Jiang Qiao Xia Xia Kang Shan Wang Ji-Hong Yu Wen-Feng Ni Xiao-Qin Qi Ying-Na Zhang jin-Bao Han Gang Liu Lei hou Zhi-Chun Feng Liu-Ming Huang Clinical Biobank Center Medical Innovation Research Division of ChinesePLA General HospitalBeijingChina Institute of Basic Medical Sciences Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Senior department of Pediatrics The Seventh Medical Center of PLA General HospitalBeijing 100700China department of Neurology The First Medical CenterChinese PLA General HospitalBeijing 100853China department of Emergency Center National Center for Children's HealthBeijing Children's HospitalCapital Medical UniversityBeijing 100045China

Background Necrotizing enterocolitis(NEC)is the most common severe gastrointestinal emergency in *** designed this study to identify the pathogenic microorganisms of NEC in the microbiota of the small intestine of *** Using the 16S ribosomal DNA(rDNA)sequencing method,we compared and analyzed the structure and diversity of microbiotas in the intestinal feces of different groups of neonates:patients undergoing jejunostomy to treat NEC(NP group),neonates undergoing jejunostomy to treat other conditions(NN group),and neonates with NEC undergoing conservative treatment(NC group).We took intestinal feces and saliva samples from patients at different time *** The beta diversities of the NP,NN,and NC groups were all *** comparing the beta diversities between different time points in the NP group,we found similar beta diversities at time points El to E3 but significant differences between the E2-E3 and E4 time points:the abundances of Klebsiella and Enterococcus(Proteobacteria)were higher at the E1-E3 time points;the abundance of Escherichia-Shigella(Proteobacteria)increased at the E2 time point,and the abundance of Klebsiella decreased significantly,whereas that of Streptococcus increased significantly at the E4 time *** Our results suggest that the pathological changes of intestinal necrosis in the small intestine of infants with NEC are not directly caused by excessive proliferation of pathogenic bacteria in the small *** sources of microbiota in the small intestine of neonates,especially in premature infants,may be affected by multiple factors.

关键词： Microbiota Necrotizing enterocolitis-Small intestine 16S rDNA