检索结果-南通市图书馆

Transient Responses of Flexible Non-uniform Spinning Shaft with Nonlinear and Asymmetric Supports

在线全文

学校读者我要写书评

暂无评论

Journal of shanghai university(English Edition) 2001年第1期5卷 35-39页

作者： ZHU Huai liang department of mechanics, College of Sciences, shanghai university, shanghai 200436, china ost.tau.ac.il

In this paper, a hybrid approach was developed to investigate the transient responses of a multi span non uniform flexible spinning shaft with nonlinear and asymmetric supports. The non uniform spinning shaft with variable parameters was modeled as a Bernoulli Euler beam column with sectional constant cross section properties by the finite element method. The supporting stiffness behavior of the nonlinear supports was described as a piecewise linear and asymmetric model. The equations of motion in the matrix form of a multi span non uniform spinning shaft with nonlinear and asymmetric supports were formulated using Hamilton's principle and the assumed mode method. As an example, a spinning rocket with many variable stiffness supports was numerically simulated by the direct integration method. The transient response and dynamic behavior of this rotate dynamic system are analyzed.

关键词： spinning shaft nonlinear support asymmetric support dynamics transient response

THE INDUCED REPRESENTATION OF C^＊-GROUPOID DYNAMIC SYSTEMS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 1996年第1期17卷 103-114页

作者： FANG XIAOCHUN(department of Mathematics, Tongji university, shanghai 200029, china.) TONGJI UNIV DEPT MATHSHANGHAI 200029PEOPLES R CHINA

Let G be a second countable locally compact groupoid with Haar system {λu}, H be a closed subgroupoid containing Go with Haar system {λuH}. *** introduced the C*-Groupoid dynamic system (G, A, α) and its reduced crossed product Cr.d(G, A) in [2], where A is a C*-algebra, α is the homomorphism G→Aut(A). In this paper the author introduces the C*-groupoid dynamic systems (H, A, α|H) and (H\G2, A, α) induced by (G, A, α) and proves that C~*red(H, A) and C~*red(H\G2, A) are strongly Morita equivalent. Moreover the induced representation from C~*red(H, A) to C~*red(G, A) is got.

关键词： C~*-groupoid dynamic system Induced representation Haar system

EXPERIMENTAL INVESTIGATIONS ON DIFFUSION CHARACTERISTICS OF HIGH CONCENTRATION JET FLOW IN NEAR REGION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2001年第1期13卷 117-121页

作者： Zhang Yan, Wang Dao-zeng, Fan Jing-yu shanghai university, shanghai Institute of Applied Mathematics and mechanics, shanghai 200072, china Inst. of Appl. Math. and Mech. Shanghai Univ. Shanghai 200072 China

WT5”BZ]The diffusion characteristics of the high concentration jet flow issued from a round nozzle above the free surface into moving waterbody were experimentally investigated. By means of flow visualization technique, the diffusion behavior of the high concentration jet was observed and analysed, Concentration distribution in the near region was obtained by sampling and quantitative measurements. Experimental results indicate that the diffusion mechanics of the high concentration jet flow are greatly influenced by initial momentum, buoyancy, turbulent structure, ambient current and boundary conditions, showing complicated flow patterns and concentration distribution characteristics that are different from previous results for submerged jets. [WT5”HZ]

关键词： et flow high concentration diffusion turbulent structure

NUMERICAL SIMULATION OF TWO-PHASE GRAVITY CURRENTS OVER A POROUS SUBSTRATE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2003年第5期15卷 81-90页

作者： Zhou Liang , Hu Yue, Zhang Hui sheng department of mechanics and Engineering Science, Fudan university, shanghai 200433, china, department of mechanics and Engineering Science Fudan University Shanghai 200433 China

Based on shallow-water approximations the governing equations for twodimensional two-phase gravity currents over a porous substrate and some appropriate boundaryconditions were introduced. With on characteristic interpolations the numerical boundary conditionswere introduced and a series of exact solutions were constructed. Numerical a-nalysis were made byusing the two-step Lax scheme, second-order TVD scheme, third-order ENO scheme and fifth-order WE NOscheme combined with second- and third-order TVD-Runge-Kutta method is given. It is found that forpractice applications the second-order TVD scheme combined with the second-order TVD- Runge- Kuttamethod is an economical and suitable choice.

关键词： two-phase gravity currents porous substrate numerical simulation

Practical Laser Linewidth Limit

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 2000年第1期9卷 21-24页

作者： HU Zongfu SHEN Huiming (department Telecommunication,shanghai Tiedao university,shanghai 200331,china) 上海铁道大学上海

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｓｉｎｃｅｌａｓｅｒｃａｍｅｏｕｔ,ｍｕｃｈａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｐａｉｄｔｏｎａｒｒｏｗｌｉｎｅｗｉｄｔｈｌａｓｅｒｓ,ａｎｄｍａｎｙｐｒｏｇｒｅｓｓｅｓｈａｖｅｂｅｅｎｍａ... 详细信息

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｓｉｎｃｅｌａｓｅｒｃａｍｅｏｕｔ,ｍｕｃｈａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｐａｉｄｔｏｎａｒｒｏｗｌｉｎｅｗｉｄｔｈｌａｓｅｒｓ,ａｎｄｍａｎｙｐｒｏｇｒｅｓｓｅｓｈａｖｅｂｅｅｎｍａｄｅｉｎｔｈｉｓｆｉｅｌｄ[1～3].Ａ...

关键词： laser linewidth limit resonator optical path length fluctuation semicondutor laser

EXPERIMENTAL STUDY ON THE VORTEX FORMATION AND ENTRAINMENT CHARACTERISTICS FOR A ROUND TRANSVERSE JET IN SHALLOW WATER

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2009年第3期21卷 386-393页

作者： FAN Jing-yu ZHANG Yan WANG Dao-zeng shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China Key Laboratory of Advanced Display and System Applications Ministry of Education and SMIT Center School of Mechatronics Engineering and Automation Shanghai University Shanghai 200072 China

The vortex formation and entrainment characteristics for a round transverse jet in shallow water were experimentally investigated by means of a combination of LIF flow visualization and PIV measurement. A scarf vortex wrapped around the main body of the jet is formed in the near-wall region due to the interaction between the resulting wall jet and sufficiently shallow crossflow, with some more or less unsteady flow properties and with spreading ranges as functions of both the velocity ratio and the water depth within the near field. The entrainment of the ambient crossflow fluid into the jet main body is closely associated with the time-evolving features of the shear layer between the jet and surrounding fluid as well as the induced vortical structures near the wall. In the case of slight impingement upon the wall, the interaction between the jet shear layer and the weak, unstable scarf vortex gives rise to an appreciable local entrainment enhancement, confined in the near-wall region in the vicinity of the stagnation point. While in the case of intense impingement upon the wall, the well-organized and stable scarf vortex gives rise to a greatly enhanced entrainment and a greatly increased lateral spreading rate nearly throughout the overall near field as compared to the conventional wall jet. In addition, the entrainment of the ambient crossflow fluid by the scarf vortex in this case occurs largely on the surface of the unique spiral roller structure by itself due to the presence of smaller and unorganized eddies, and accordingly the scarf vortex is likely to keep its spiral roller structure steadily to a relatively great downstream distance within the near field.

关键词： transverse jet shallow water vortex formation entrainment PIV measurement

Smoothness for the collision local times of bifractional Brownian motions

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2011年第9期54卷 1859-1873页

作者： SHEN GuangJun 1,2,& YAN LiTan 3 1 department of Mathematics,East china university of Science and Technology,shanghai 200237,china 2.department of Mathematics,Anhui Normal university,Wuhu 241000,china 3 department of Mathematics,Donghua university,shanghai 201620,china 1. department of Mathematics East China University of Science and Technology Shanghai 200237 China2. Department of Mathematics Anhui Normal University Wuhu 241000 China3. Department of Mathematics Donghua University Shanghai 201620 China

Let B^Hi,Ki ={ Bt^Hi,Ki, t ≥ 0}, i= 1, 2 be two independent bifractional Brownian motions with respective indices Hi ∈ （0, 1） and K∈ E （0, 1]. One of the main motivations of this paper is to investigate f0^Tδ（Bs^H1 ,K1 - the smoothness of the collision local time, introduced by Jiang and Wang in 2009, IT = f0^T δ（Bs^H1,K1）ds, T 〉 0, where 6 denotes the Dirac delta function. By an elementary method, we show that iT is smooth in the sense of the Meyer-Watanabe if and only if min{H-1K1, H2K2} 〈-1/3.

关键词： bifractional Brownian motion collision local time intersection local time chaos expansion

THE GPL-STABILITY OF RUNGE-KUTTA METHODS FORDELAY DIFFERENTIAL SYSTEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2000年第1期18卷 75-82页

作者： Biao Yang Lin Qiu Jiao-xun Kuang(department of Mathematics, shanghai Normal university, shanghai 200234, china.) 上海师范大学上海 200234

Presents a study which dealt with stability of the implicit Runge-Kutta methods for the numerical solutions of the systems of delay differential equations. Stability behavior of the methods; Exponential solutions of t... 详细信息

关键词： delay differential equation implicit Runge-Kutta methods GPL-stability

Strong law of large numbers for Markov chains indexed by an infinite tree with uniformly bounded degree

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2008年第2期51卷 195-202页

作者： HUANG HuiLin~1 YANG WeiGuo~(2+) 1 department of Mathematics,shanghai Jiaotong university,shanghai 200240,china 2 Faculty of Science,Jiangsu university,Zhenjiang 212013,china 1. department of Mathematics Shanghai Jiaotong University Shanghai 200240 China 2. Faculty of Science Jiangsu University Zhenjiang 212013 China

In this paper,we study the strong law of large numbers and Shannon-McMillan (S-M) theorem for Markov chains indexed by an infinite tree with uniformly bounded *** results generalize the analogous results on a homogene... 详细信息

关键词： Markov chains Shannon-McMillan theorem strong law of large numbers uniformly bounded tree 60F15 60J10