检索结果-南通市图书馆

Science china(Technological Sciences) 2009年第3期52卷 584-589页

作者： XU YePeng1 & ZHOU Ding2 1 School of Science, nanjing university of Science and technology, nanjing 210094, china 2.college of civil engineer.ng, nanjing university of technology, nanjing 210009, china School of Science Nanjing University of Science and Technology Nanjing China college of civil engineer.ng Nanjing University of Technology Nanjing China

This paper studies the bending of simple-supported rectangular plate on point supports, line supports and elastic foundation. On the basis of three-dimensional elasticity theory, the exact expressions of the displacement functions, which satisfy the governing differential equations and the simply supported boundary conditions at four edges of the plate, are analytically derived. The reaction forces of the in- termediate supports are regarded as the unknown external forces acting on the lower surface of the plate. The unknown coefficients are then determined by the boundary conditions on the upper and lower surfaces of the plate. Comparing the numerical results obtained from the proposed method to those obtained from Kirchhoff plate theory, Mindlin plate theory and those obtained from the commer- cial finite element software ANSYS, the high accuracy of the present method has been demonstrated.

关键词： rectangular plate point support line support elastic foundation displacement stress three-dimensional elasticity solution

Web Application Comprehension Based on Dependence Analysis

在线全文

学校读者我要写书评

暂无评论

Wuhan university Journal of Natural Sciences 2004年第5期9卷 731-734页

作者： WU Jun-hua 1,2 , XU Bao-wen 1 , JIAng Ji-xiang 1 1.Department of Computer Science and engineer.ng, Southeast university, nanjing 210096, Jiangsu, china 2.college of Computer Science and engineer.ng, nanjing university of technology, nanjing 210009, Jiangsu , china Department of Computer Science and engineer.ng Southeast University Nanjing Jiangsu China college of Computer Science and engineer.ng Najing University of Technology Nanjing Jiangsu China

Many research indicate a lot of money and time are spent on maintaining and modifying program delivered. So the policies to support program comprehension are very important. Program comprehension is a crucial and difficult task. Insufficient design, illogical code structure, short documents will enhance the comprehensive difficulty. Developing Web application is usually a process with quick implementation and delivery. In addition, generally a Web application is coded by combining mark language statements with some embedded applets. Such programming mode affects comprehension of Web applications disadvantageously. This paper proposes a method to improving understanding Web by dependence analysis and slice technology. Key words Web application comprehension - program dependence - hyper graph - pogram slicing CLC number TP 311 Foundation item: Supported in part by the Young Scientist’s Fund of NSFC (60373066, 60303024). National Grand Fundamental Research 973 Program of china (2002CB312000) and National Research Foundation for the Doctoral Program of Higher Education of chinaBiography: WU Jun-hua (1965-), female, Ph. D. research direction: software engineer.ng.

关键词： Web application comprehension program dependence hyper graph pogram slicing

Molecular group dynamics study on slip flow of thin fluid film based on the Hamaker hypotheses

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第7期53卷 1833-1838页

作者： ZHOU JianFeng, SHAO ChunLei & GU BoQin college of Mechanical and Power engineer.ng, nanjing university of technology, nanjing 210009, china college of Mechanical and Power engineer.ng Nanjing University of Technology Nanjing China

The thin fluid film was assumed to consist of a number of spherical fluid molecular groups and the attractive forces of molecular group pairs were calculated by the derived equation according to the three Hamaker homogeneous material hypotheses. Regarding each molecular group as a dynamics individual, the simulation method for the shearing motion of multilayer fluid molecular groups, which was initiated by two moving walls, was proposed based on the Verlet velocity iterative algorithm. The simulations reveal that the velocities of fluid molecular groups change about their respective mean velocities within a narrow range in steady state. It is also found that the velocity slips occur at the wall boundary and in a certain number of fluid film layers close to the wall. Because the dimension of molecular group and the number of group layers are not restricted, the hypothetical thickness of fluid film model can be enlarged from nanometer to micron by using the proposed simulation method.

关键词： Hamaker hypotheses molecular group velocity slip Lennard-Jones potential

Cross-linked Polyethylenimine as Potential DNA Vector for Gene Delivery with High Efficiency and Low Cytotoxicity

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2006年第11期38卷 780-787页

作者： Wei DOng~(1,2) Guang-Hui JIN~1 Shu-Feng LI~(1,3) Qi-Ming SUN~1 Ding-Yuan MA~1 Zi-Chun HUA~1 1 State Key Laboratory of Pharmaceutical Biotechnology,college of Life Science,nanjing university,nanjing 210093,china 2 School of Chemical engineer.ng nanjing university of Science and technology,nanjing 210094,china 3 college of Basic Medical Science,Southeast university,nanjing 210009,china State Key Laboratory of Pharmaceutical Biotechnology College of Life Science Nanjing UniversityNanjing 210093 China School of Chemical engineer.ng Nanjing University of Science and TechnologyNanjing 210094 China college of Basic Medical Science Southeast UniversityNanjing 210009 China

Polyethylenimine (PEI) has been known as an efficient gene carrier with the highest cationiccharge *** transfection efficiency of PEI,along with its cytotoxicity,strongly depends on itsmolecular *** enhance its gene delivery efficiency and minimize cytotoxicity,we have synthesizedsmall cross-linked PEI with biodegradable linkages and evaluated their transfection efficiencies in *** study,branched PEI with a molecular weight of 800 Da was cross-linked by small diacrylate[1,4-butanediol diacrylate or ethyleneglycol dimethacrylate (EGDMA)] for 2-6 *** efficiencies of thecross-linked PEI in in vitro transfection of plasmid DNA containing enhanced green fluorescent protein(EGFP) reporter gene were assessed in melanoma B 16F10 cell line and other cell *** cytometrywas used to quantify the cellular entry efficiency of plasmid and the transgene expression *** of the cross-linked PEI in these cells were evaluated by MTT ***-PEI 800-4h,atypical cross-linked PEI reported here,mediated a more efficient expression of reporter gene than thecommercially available 25-kDa branched PEI control,and resulted in a 9-fold increase in gene deliveryin B16F10 cells and a 16-fold increase in 293T cells,while no cytotoxicity was found at the optimizedcondition for gene ***,the transfection activity of polyplexes was preserved in thepresence of serum proteins.

关键词： polyethylenimine gene delivery cytotoxicity B16F10 293T cell line

Integrated intelligent control analysis on semi-active structures by using magnetorheological dampers

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2008年第12期51卷 2270-2284页

作者： XU ZhaoDong1 & GUO YingQing2 1civil engineer.ng college, Southeast university, nanjing 210096, china 2 Automation college, Southeast university, nanjing 210096, china civil engineer.ng college Southeast University Nanjing China Automation college Southeast University Nanjing China

The control strategy is very important for semiactive control or active control systems. An integrated intelligent control strategy for building structures incorpo rated with magnetorheological (MR) dampers subjected to earthquake excitation is proposed. In this strategy, the time-delay problem is solved by a neural network and the control currents of the MR dampers are determined quickly by a fuzzy controller. Through a numerical example of a three-storey structure with one MR damper installed in the first floor, the seismic responses of the uncontrolled, the intelligently controlled, the passiveon controlled, and the passive-off controlled structures under different earthquake excitations are analyzed. Based on the numerical results, it can be found that the time domain and the frequency domain responses are reduced effectively when the MR damper is added in the structure, and the integrated intelligent control strategy has a better earthquake mitigation effect.

关键词： magnetorheological damper semi-active control intelligent

Resolution method for overlapping peaks based on the fractional-order differential

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2007年第6期50卷 797-805页

作者： LI YuanLu1, YU ShengLin2 & ZHEng Gang2 1 college of Information & Control, nanjing university of Information Science & technology, nanjing 210044, china 2.college of Automation engineer.ng, nanjing university of Aeronautics and Astronautics, nanjing 210016, china college of Information & Control Nanjing University of Information Science & Technology Nanjing China college of Automation engineer.ng Nanjing University of Aeronautics and Astronautics Nanjing China

Equations between the differential order and the maximum of the fractional-order differential for the specified peak signals are developed based on the variation of the maximum of the specified peak signals at different orders. Also, equations between the differential order and the zero-crossing of the fractional-order differential of the specified peak signals are proposed according to the variation of the zero-crossing of the specified peak signals at different orders. Characteristic paramters of the Gaus- sian peak, Lorentzian peak, and Tsallis peak can be estimated using estimator I and estimator II which are obtained by the equations above. As a result, a new method is presented to resolve the overlapped peaks signal. Firstly, a fractional-order differential of the specified peak signals is obtained with the fractional-order differentiation filter. Then, characteristic paramters of the specified peak signals can be extracted using estimator I and estimator II. Finally, the Tsallis peak is used as a model to assign the overlapping peak signals correctly. Experimental results show that the proposed method is efficient and effective for the simulated overlapping peaks and detected overlapping voltammetric peak signals.

关键词： fractional-order differentiation filter, fractional-order differential, overlapping peaks, voltammetric peak

Modal identification of system driven by lévy random excitation based on continuous time AR model

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2009年第12期52卷 3649-3653页

作者： DU XiuLi 1,2 &WAng FengQuan 1 1 college of civil engineer.ng,Southeast university,nanjing 210096,china 2 School of Mathematical Sciences,nanjing Normal university,nanjing 210097,china college of civil engineer.ng Southeast University Nanjing China School of Mathematical Sciences Nanjing Normal University Nanjing China

Based on the continuous time AR model,this paper presents a new time-domain modal identification method of LTI system driven by the uniformly modulated lévy random *** structural dynamic equation is first transformed into the observation equation and the state equation(namely,stochastic differential equation).Based on the property of the strong solution of the stochastic differential equation,the uniformly modulated function is identified *** by virtue of the Girsanov theorem,we present the exact maximum likelihood estimators of ***,the modal parameters are identified by eigen *** results show that the method not only has high precision and robustness but also has very high computing efficiency.

关键词： modal identification uniformly modulated function CAR model lévy process exact maximum likelihood estimator

A Raw Signal Simulator for Bistatic SAR

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2009年第4期22卷 434-443页

作者： Xia Weijie,Zhou Jianjiang college of Information Science and technology,nanjing university of Aeronautics and Astronautics,nanjing 210016,china college of Information Science and technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

This article proposes a new efficient raw signal simulator for the bistatic synthetic aperture radar （SAR） based on 2D fast Fourier transform （FFT） to deal with cases of both ideal trajectory and trajectory deviation. It begins with analyzing the geometric configuration and the range history of the bistatic SAR in side-looking and squint modes of ideal trajectory as well as trajectory deviation. Then a detailed and mathematical study is conducted on the equivalence relation of bistatic-to-monostatic applications （BTMA） in the case of ideal trajectory and trajectory deviation. Also a set of formulas are derived for the equivalence relation between bistatic SAR and monostatic SAR on some reasonable assumptions. Therefore, the application of the simulation method based on the 2D FFT for the monostatic SAR can be extended to the case of bistatic SAR. Finally, the simulation results prove the validity of this method. By comparing the efficiency of the proposed method with that of the time domain method, it is shown that the former is a few orders of magnitude higher.

关键词： bistatic synthetic aperture radar raw signal simulation fast Fourier transform

Study on design pressure of in-service welding pipes

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2006年第4期49卷 434-444页

作者： XUE Xiaolong1, ZHU Jiagui2 & SAng Zhifu1 1. college of Mechanical and Power engineer.ng, nanjing university of technology, nanjing 210009, china 2. nanjing Yangzi Petrochemical Maintenance and Installation Co. Ltd., nanjing 210048, china college of Mechanical and Power engineer.ng Nanjing University of Technology Nanjing China nanjing Yangzi Petrochemical Maintenance and Installation Co. Ltd. Nanjing China

A method of predicting design pressure and burn-through of in-service welding pipes was established. Temperature distributions of in-service welding under variable parameters were simulated by FEM. The effect of flowing of internal media was regarded as forced convection. Based on the numerical results, design pressure of the pipe can be obtained and burn-through can be predicted. It can be concluded that the design pressure decreases with the increasing of heat input. RSF and design pressure of the pipe increase with the increasing of flow rate. There is a range in which the increase changes greatly. For in-service welding, the range should be considered adequately to determine operating condition optimally. RSF increases with the increasing of pipe wall thickness. While the thickness increases to an extent, RSF shows little increase. Accord- ing to the curves of design pressure versus different parameters, safe working pressure can be achieved.

关键词： in-service welding, heat input, flow rate, pipe wall thickness, design pressure.

Influences of low-Ti substitution for La and Mg on the electrochemical and kinetic characteristics of AB_3-type hydrogen storage alloy electrodes

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第1期53卷 242-247页

作者： DOng ZhenWei1,2,WU YaoMing1,MA LiQun2,SHEN XiaoDong2 & WAng LiMin1 1 State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,C hangchun 130022,china 2.college of Material Science and engineer.ng,nanjing university of technology,nanjing 210009,china State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China college of Material Science and engineer.ng Nanjing University of Technology Nanjing China

The(La0.67Mg0.33)1-xTixNi2.75Co0.25(x = 0,0.05,0.10,0.15 and 0.20,at%) alloys were synthesized by arc melting and subsequent heat solid-liquid diffusing *** structure,electrochemical properties and kinetic characteristics of the alloys were investigated *** results showed that all the alloys mainly consisted of the(La,Mg)Ni3,LaNi5 phases,and the lattice parameters and the cell volumes of the(La,Mg)Ni3 and LaNi5 phases decreased with increasing Ti *** alloy electrodes could be activated to reach their maximum discharge capacity within five *** cycle life after 100 charge/discharge cycles(C100/Cmax) and the high-rate dischargeability at a discharge current density of 1200 mA/g first increased and then *** the results showed that low-Ti content in AB3-type hydrogen storage alloys was beneficial to improvements of the overall electrochemical properties,and the optimum overall electrochemical performance of the alloy electrodes was obtained when x = 0.05.

关键词： AB3-type alloy metal hydride electrode microstructure electrochemical property kinetic characteristic