检索结果-南通市图书馆

Guided wave propagation in multilayered piezoelectric structures

Science china(Physics,mechanics & Astronomy) 2009年第7期52卷 1094-1104页

作者： GUO YongQiang1, CHEN WeiQiu2.3 & ZHANG YongLiang4 1 Key Laboratory of mechanics on Disaster and Environment in Western china, Ministry of Education, and School of Civil {2. and mechanics, Lanzhou University, Lanzhou 730000, china 2.Key Laboratory of Soft Soils and Geoenvironmental {2., Ministry of Education, and department of Civil {2., Zhejiang University, Hangzhou 310058, china 3 department of {2. mechanics, Zhejiang University, Hangzhou 31002., china 4 School of Civil {2., Lanzhou Jiaotong University, Lanzhou 730070, china Key Laboratory of mechanics on Disaster and Environment in Western china Ministry of Education and School of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 China Key Laboratory of Soft Soils and Geoenvironmental engineering Ministry of Education and Department of Civil Engineering Zhejiang University Hangzhou 310058 China department of engineering {2. Zhejiang University Hangzhou 310027 China School of Civil engineering Lanzhou Jiaotong University Lanzhou 730070 China

A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

关键词： multilayered piezoelectric structures the method of reverberation-ray matrix guided waves dispersion characteristic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis of Nanocrystalline α-Mo_2. from Peroxomolybdenum Compounds

引用

复旦学报（自然科学版） 2007年第5期46卷 859-860页

作者： Beibei Zhang1, Huaming Li1, Huoming Shu2. Wenshuai Zhu1, Jiexiang Xia1(1.College of Chemistry and Chemical engineering, jiangsu University,{2., china 2.department of Chemistry, Hainan Normal University, Haikou 5702.8, china) College of Chemistry and Chemical engineering jiangsu University Zhenjiang 212013 department of Chemistry Hainan Normal University Haikou 570228

1 Introduction Considerable attentions have been focused on transition metal carbide because of their numerous valuable properties, particularly of excellent catalysis similar to noble metal[1]. There are many routes[2.to synthesize molybdenum carbide. Among them, the temperature programmed reduction of MoO3 using the mixture of hydrocarbon and hydrogen is the most promising procedure to prepare carbide catalyst. Traditionally, CH4/H2.and C2.6/H2.are the most widely used to be the carburizing resource. ...

关键词： α-Mo2. synthesis nanocrystalline peroxopolymolybdic compounds

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The dispersion characteristics of the waves propagating in a spinning single-walled carbon nanotube

引用

Science china(Physics,mechanics & Astronomy) 2011年第10期Mechanics & Astronomy) .卷 1854-1865页

作者： CHAN K. T.1& ZHAO YaPu2.1Mechanical engineering department, The Hong Kong Polytechnic University, Hung Hom, Hong Kong,{2. 2.tate Key Laboratory of Nonlinear mechanics (LNM), Institute of mechanics, Chinese Academy of Sciences, Beijing 100190,{2. 1. Mechanical engineering department The Hong Kong Polytechnic University Hung Hom Hong Kong China2. State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

As the nano-motor becomes a mechanical reality, its prototype can be envisaged as nano-sized rotating machinery at a situation,albeit for different purposes, like that in the first half of the 2.th century during which rotor dynamics has contributed toboosting machine power capacity. Accordingly, we take the benefit of hindsight to develop a classical framework of vibrationanalysis. Essentially, the equations of motion are formulated to cope with both the special carbon-nanotube properties and thefirst author’s previously developed spinning beam formalism, establishing a model satisfactorily verified by some availablemolecular dynamics (MD) data and classical spinning beam results extracted from the literature. The model is inexpensivebased on continuum mechanics as an alternative to the less-flexible MD method for simulating wave motion of the spinningsingle-walled carbon nanotube, yielding several interesting phenomena, including the fall-off and splitting of the wave charac-teristic curves and the unexpected gyroscopic phase property. Potential applications are proposed.

关键词： spinning single-walled carbon nanotube gyroscopic phase property nonlocal elasticity nonlocal Timoshenko beamtheory

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Analytical solution and semi-analytical solution for anisotropic functionally graded beam subject to arbitrary loading

引用

Science china(Physics,mechanics & Astronomy) 2009年第8期52卷 1244-1256页

作者： HUANG DeJin1,2.DING HaoJiang1 & CHEN WeiQiu3 1 Key Laboratory of Soft Soils and Geoenvironmental engineering,Ministry of Education,Zhejiang University,Hangzhou 31002.,china 2.Faculty of engineering,Ningbo University,Ningbo 3152.1,china 3 department of engineering mechanics,Zhejiang University,Hangzhou 31002.,china Key Laboratory of Soft Soils and Geoenvironmental engineering Ministry of Education Zhejiang University Hangzhou 310027 China Faculty of engineering Ningbo University Ningbo 315211 China department of engineering {2. Zhejiang University Hangzhou 310027 China

Analytical and semi-analytical solutions are presented for anisotropic functionally graded beams subject to an arbitrary load,which can be expanded in terms of sinusoidal *** plane stress problems,the stress function is assumed to consist of two parts,one being a product of a trigonometric function of the longitudinal coordinate(x) and an undetermined function of the thickness coordinate(y),and the other a linear polynomial of x with unknown coefficients depending on *** governing equations satisfied by these y-dependent functions are *** expressions for stresses,resultant forces and displacements are then deduced,with integral constants determinable from the boundary *** the analytical solution is derived for the beam with material coefficients varying exponentially or in a power law along the thickness,the semi-analytical solution is sought by making use of the sub-layer approximation for the beam with an arbitrary variation of material parameters along the *** present analysis is applicable to beams with various boundary conditions at the two *** numerical examples are presented for validation of the theory and illustration of the effects of certain parameters.

关键词： anisotropic material functionally graded arbitrary loading stress function analytical solution semi-analytical solution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in numerical methods for the solution of population balance equations for disperse phase systems

引用

Science china Chemistry 2009年第8期52卷 1063-1079页

作者： SU JunWei1,GU ZhaoLin2.3 & XU X.Yun41 department of Mechanical engineering and Automation,School of Mechanical engineering,Xi’an Jiaotong University,Xi’an 710049,china 2.Key Laboratory of mechanics on Disaster and Environment in Western china,Ministry of Education,Lanzhou 730000,china 3 department of Environmental Science and Technology,School of Human Settlements and Civil engineering,Xi’an Jiaotong University,Xi’an 710049,china 4 department of Chemical engineering,Imperial College London,London SW7 2.Z,UK 1. department of Mechanical engineering and Automation School of Mechanical Engineering Xi’an Jiaotong University Xi’an 710049 China 2. Key Laboratory of mechanics on Disaster and Environment in Western china Ministry of Education Lanzhou 730000 China 3. department of Environmental Science and Technology School of Human Settlements and Civil Engineering Xi’an Jiaotong University Xi’an 710049 China 4. department of Chemical engineering Imperial College London London SW7 2AZ UK

Accurate prediction of the evolution of particle size distribution is critical to determining the dynamic flow structure of a disperse phase system.A population balance equation(PBE),a non-linear hyperbolic equation of the number density function,is usually employed to describe the micro-behavior(aggregation,breakage,growth,etc.) of a disperse phase and its effect on particle size *** solution is the only choice in most *** this paper,three different numerical methods(direct discretization methods,Monte Carlo methods,and moment methods) for the solution of a PBE are evaluated with regard to their ease of implementation,computational load and numerical *** attention is paid to the relatively new and superior moment methods including quadrature method of moments(QMOM),direct quadrature method of moments(DQMOM),modified quadrature method of moments(M-QMOM),adaptive direct quadrature method of moments(ADQMOM),fixed pivot quadrature method of moments(FPQMOM),moving particle ensemble method(MPEM) and local fixed pivot quadrature method of moments(LFPQMOM).The prospects of these methods are discussed in the final section,based on their individual merits and current state of development of the field.

关键词： population balance equation direct discretization method Monte Carlo method moment methods disperse phase system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Some variational principles in electroelastic media under finite deformation

引用

Science china(Physics,mechanics & Astronomy) 2008年第9期51卷 1390-1402页

作者： KUANG ZhenBang department of engineering {2.,Shanghai Jiaotong University,Shanghai 2.02.0,china department of engineering {2. Shanghai Jiaotong University Shanghai 200240 China

It is proposed that the universal thermodynamic energy variational principle is in-cluded in the first law of thermodynamics. Some variational principles in the elec-troelastic media under finite deformation are derived from this universal thermo-dynamic variational principle. It is suggested that in the general electroelastic analysis the environment should be considered together with the discussed elec-troelastic medium. For the variational principle of nonlinear electroelastic media the variation of the electric potential is coupled with the virtual displacement,and the variation of the initial volume should be considered. The Maxwell stress in the initial configuration is naturally derived from this variational principle and it is unique in the second order precision.

关键词： first law of thermodynamics variational principle the electroelastic media the governing equation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Virtual multi-dimensional internal bonds model and its application in simulation of rock mass

引用

Science china(Technological Sciences) 2008年第2期51卷 192-201页

作者： ZHANG ZhenNan1,2.& GE XiuRun3,4 1 department of Civil engineering,Shanghai University,Shanghai 2.0072.{2. 2.Shanghai Institute of Applied Mathematics and mechanics,Shanghai University,Shanghai 2.0072. china 3 Institute of Geotechnical engineering,Shanghai Jiao Tong University,Shanghai 2.0030,{2. 4 Institute of Rock and Soil mechanics,Chinese Academy of Sciences,Wuhan 430071,{2. 1. department of Civil engineering Shanghai University Shanghai 200072 China 2. Shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China 3. Institute of Geotechnical engineering Shanghai Jiao Tong University Shanghai 200030 China 4. Institute of Rock and Soil mechanics Chinese Academy of Sciences Wuhan 430071 China

VMIB (virtual multi-dimensional internal bonds) is a multiscale mechanical model developed from the VIB (virtual internal bond) theory. In VIB theory,the solid mate-rial is considered to consist of random-distributed material particles in microscale. These particles are connected with normal bonds. The macro constitutive relation is derived from the cohesive law between particles. However,in VMIB,the micro particles are connected with both normal and shear bonds. The macro constitutive relation is derived in terms of bond stiffness coefficients. It has been theoretically certified that there exists a corresponding relationship between the two bond stiffness coefficients and the two macro material constants,i.e. the Young’s modulus and Poisson ratio. This corresponding relationship suggests that it should be necessary and sufficient to simultaneously account for the normal and shear interactions between particles. Due to the fact that the fracture criterion is directly incorporated into the constitutive relation,both VIB and VMIB present many advantages in simulating fractures of materials. In the damage model of rock mass,a damage tensor is usually defined to describe the distribution of cracks. The damage value in one direction determines the relative stiffness of rock mass in this direction. In VMIB solid,the relative distribution density of micro bonds in one direction determines the relative macro stiffness of the material in this direction. The effects of the damage value and the relative distribution density of bonds are consistent. To simulate the failure behavior of rock mass with VMIB,the presented paper sets up a quantitative relationship between the damage tensor and the rela-tive distribution density of bonds. Comparison of the theoretical and the experi-mental results shows that VMIB model can represent the effect of distributed cracks on rock mass with this relationship. The presented work provides a founda-tion for further simulating fracture behavior

关键词： VMIB (virtual multi-dimensional internal bonds) rock mass VIB (virtual internal bonds) multi-cracked body numerical simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Protective effect of clodronate-containing liposomes on intestinal mucosal injury in rats with severe acute pancreatitis

引用

Hepatobiliary & Pancreatic Diseases International 2011年第5期10卷 544-551页

作者： Jian-Xin Zhang, Sheng-Chun Dang, Kai Yin and De-Li Jiang department of General Surgery, Affiliated Hospital of jiangsu University, {2. 2.2.01, china School of Chemistry and Chemical engineering of jiangsu University, zhenjiang 2.2.13, china [a] department of General Surgery Affiliated Hospital of Jiangsu University Zhenjiang 212001 China [b] School of Chemistry and Chemical engineering of jiangsu University Zhenjiang212013 China

BACKGROUND: Severe acute pancreatitis (SAP) can result in intestinal mucosal injury. This study aimed to demonstrate the protective effect of clodronate-containing liposomes on intestinal mucosal injury in rats with SAP. METHODS: Liposomes containing clodronate or phosphate buffered saline (PBS) were prepared by the thin-film method SAP models were prepared by a uniform injection of sodium taurocholate (2.mL/kg body weight) into the subcapsular space of the pancreas. Sprague-Dawley rats were randomly divided into a control group (C group), a SAP plus PBS-containing liposomes group (P group) and a SAP plus clodronate-containing liposomes group (T group). At 2.and 6 hours after the establishment of SAP models, 2.mL blood samples were taken from the superior mesenteric vein to measure the contents of serum TNF-α and IL-12. Pathological changes in the intestine and pancreas were observed using hematoxylin and eosin staining, while apoptosis was detected using TUNEL staining. In addition, the macrophage markers cluster of differentiation 68 (CD68) in the intestinal tissue was assessed with immunohistochemistry. RESULTS: At the two time points, the levels of TNF-α and IL-12.in the P group were higher than those in the C group (P2.decreased in the T group (P<0.05). The pathological scores of the intestinal mucosa and pancreas in the T group were lower than those of the P group. In the T group, large numbers of TUNEL-positive cells were observed, but none or few in the C and P groups. The number of CD68-positive macrophages decreased in the T ***: Clodronate-containing liposomes have prote- ctive effects against intestinal mucosal injury in rats with SAP. The blockade of macrophages may provide a novel therapeutic strategy in SAP.

关键词： pancreatitis clodronate disodium macrophage intestinal mucosal injury

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical analysis of natural frequency of externally prestressed concrete beam based on rigidity correction

引用

Journal of Pharmaceutical Analysis 2009年第1期21卷 31-35页

作者： Hui-xia Xiong1,2. Yao-ting Zhang11.School of Civil engineering & mechanics, Huazhong University of Science and Technology, Wuhan 430074,{2. 2.department of Civil engineering, Nanyang Institute of Technology, Nanyang 473004,{2.. School of Civil engineering and mechanics Huazhong University of Science and Technology Wuhan 430074 China department of Civil engineering Nanyang Institute of Technology Nanyang 473004 China

A dynamic test on externally prestressed simply supported concrete beams separately with three typical types of tendon distributions was conducted. The results show that the natural frequencies of the beams increase with the increase in the prestressing force at the tensioning stage, and the natural frequencies decrease after the cracks occur in the beams. Following the calculation formula of natural frequency of externally prestressed beam, which was reported in a literature, the natural frequencies of the experimental beams are calculated, and big errors are found between the test results and the calculated ones of natural frequency values. As a result, this paper has tried to adopt two methods to correct the rigidity parameter of the concrete beam in the formula for natural frequency calculation, and to use the corrected formula to calculate the frequencies of the experimental beams. The calculation results indicate a good consistency with the experimental ones, which verifies the feasibility of the corrected formula.

关键词： externally prestressed concrete beam natural frequency rigidity correction regression analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Undercooling and solidification of germanium melts studied by differential scanning calorimeter

引用

Science china(Physics,mechanics & Astronomy) 2004年第5期47卷 581-587页

作者： LI Qiang1,2.ZHU Yuying2.HE Yunha3,WANG Xu2.LI Gong1,YU Jinku1 & SU Zhibin1 1.Key Laboratory of Metastable Materials Science &Technology,Yanshan University,QinhuangdaO 066004,china 2.department of Mechanical {2.,Yanshan University,Qinhuangdao 066004,china 3.department of Environmental & Chemical {2.,Yanshan University,QinhuangdaO 066004. china 1. Key Laboratory of Metastable Materials Science & Technology Yanshan University 066004 Qinhuangdao China 2. department of Mechanical engineering Yanshan University 066004 Qinhuangdao China 3. department of Environmental & Chemical engineering Yanshan University 066004 Qinhuangdao China

Differential scanning calorimeter combined with flux(dehydrated B2.3) processing was used to realize and precisely measure the undercooling of germanium *** highest undercooling obtained in this way was 190 *** between the undercooling and cooling rate or overheating tem-perature are analyzed *** undercooling obtained is found to be increased with increasing of the cooling rate in the range from 5 to 40 K/*** a given cooling rate,the undercooling reached is increased with the increasing of the overheating temperature of the melt,but tends to be constant at *** of the undercooled germanium melt is investigated at the same *** is clearly shown that,the higher the cooling rate,the shorter time is needed for crystallization.

关键词： germanium, undercooling, solidification, differential scanning calorimeter.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：