检索结果-南通市图书馆

Methods and advances in the study of aeroelasticity with uncertainties

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2014年第3期27卷 461-474页

作者： dai Yuting Yang Chao School of Aeronautic Science and Engineering Beihang University

Uncertainties denote the operators which describe data error, numerical error and model error in the mathematical methods. The study of aeroelasticity with uncertainty embedded in the subsystems, such as the uncertainty in the modeling of structures and aerodynamics, has been a hot topic in the last decades. In this paper, advances of the analysis and design in aeroelasticity with uncertainty are summarized in detail. According to the non-probabilistic or probabilistic uncer- tainty, the developments of theories, methods and experiments with application to both robust and probabilistic aeroelasticity analysis are presented, respectively. In addition, the advances in aeroelastic design considering either probabilistic or non-probabilistic uncertainties are introduced along with aeroelastic analysis. This review focuses on the robust aeroelasticity study based on the structured singular value method, namely the ~t method. It covers the numerical calculation algo- rithm of the structured singular value, uncertainty model construction, robust aeroelastic stability analysis algorithms, uncertainty level verification, and robust flutter boundary prediction in the flight test, etc. The key results and conclusions are explored. Finally, several promising problems on aeroelasticity with uncertainty are proposed for future investigation.

关键词： Polynomial chaos expansion Probabilisticity Robustness Structured singular value Uncertainty

Numerical simulation of flow and heat transfer in a random packed bed

在线全文

学校读者我要写书评

暂无评论

Particuology 2010年第3期8卷 293-299页

作者： Xueyan Guo Ren dai School of Energy and Power Engineering University of Shanghai for Science and Technology S 16Jun Gong Road Shanghai 200093 China

Random packed beds have more complex interior structure than structured beds and are widely used in industry and engineering. CFD simulation was carried out to investigate and analyze the local flow and heat transfer in a 120-sphere random packed bed. 3D Navier-Stokes equation was solved with a finite volume formulation based on the Chimera meshing technique. Investigation was focused on low Reynolds number flow （Re=4.6-56.2）, which typically occurs in packed bed reactors in bio-chemical fields. Detailed temperature field information was obtained. Inhomogeneity of flow and heat transfer due to the non-uniform distribution of void fraction was discussed and analyzed.

关键词： Packed bed Heat transfer Chimera grid Numerical simulation Low Reynolds number

PRECONDITIONING BLOCK LANCZOS ALGORITHM FOR SOLVING SYMMETRIC EIGENVALUE PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2000年第4期18卷 365-374页

作者： Hua dai Peter Lancaster Nanjing University of Aeronautics and Astronautics Naming210018China University of Calgary CalgaryCanada

A preconditioned iterative method for computing a few eigenpairs of large sparse symmetric matrices is presented in this paper. The proposed method which combines the preconditioning techniques with the efficiency of block Lanczos algorithm is suitable for determination of the extreme eigenvalues as well as their multiplicities. The global convergence and the asymptotically quadratic convergence of the new method are also demonstrated. [ABSTRACT FROM AUTHOR]

关键词： eigenvalue eigenvector sparse matrices Lanczos method preconditioning

Synergistic and interference effects in coaxial mixers: Numerical analysis of the power consumption

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第4期26卷 684-694页

作者： Juan Huang Gance dai School of Perfume and Aroma Technology Shanghai Institute of Technology State Key Laboratory of Chemical Engineering East China University of Science and Technology

This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon(HR)and inner-outer HR operated in laminar regime were studied experimentally and numerically. The interaction implies synergistic and interference effects, which was revealed through the investigation of axial circulation rate, energy dissipation rate and power consumption. The influence factors including rotational speed ratio,rotating mode and impeller configuration were explored systematically. Quantitative analysis of power consumption involves three parameters: rate of variation in power consumption, interactive mode and ratio of power consumption. Analysis indicated that some important properties were embodied in the power *** properties are one-way and two-way interactions, critical speed ratio and dominant impeller. Finally, a new suggestion for power estimation was given.

关键词： Numerical simulation Mixing Laminar flow Coaxial mixers Power consumption Interaction

Attitude synchronization for multiple spacecraft with input constraints

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2014年第2期27卷 321-327页

作者： Lyu Jianting Gao dai School of Mathematical Sciences Heilongjiang University School of Mechanical and Electrical Engineering Harbin Institute of Technology

The attitude synchronization problem for multiple spacecraft with input constraints is investigated in this paper. Two distributed control laws are presented and analyzed. First, by intro- ducing bounded function, a distributed asymptotically stable control law is proposed. Such a con- trol scheme can guarantee attitude synchronization and the control inputs of each spacecraft can be a priori bounded regardless of the number of its neighbors. Then, based on graph theory, homoge- neous method, and Lyapunov stability theory, a distributed finite-time control law is designed. Rig- orous proof shows that attitude synchronization of multiple spacecraft can be achieved in finite time, and the control scheme satisfies input saturation requirement. Finally, numerical simulations are presented to demonstrate the effectiveness and feasibility of the oroDosed schemes.

关键词： Attitude synchronization Cooperative control Finite,time control Input constraints Multiple spacecraft

Angular Distribution of Electrons Following Photoionization of n'sns ^(1)S_(0) Rydberg States in the Alkaline-Earth Atoms

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1994年第9期11卷 529-532页

作者： dai Changjian Department of Physics Zhejiang UniversityHangzhou 310027

A new characterization of the angular distribution of electron ejected from n'pns autoionizing states in the alkaline-earth atoms has been carried out from the most general expression of differential cross section of *** same approach may be extended to more complicated cases where the traditional treatment becomes *** comparison between the two methods is presented.

关键词： absorption. Electron Rydberg

COLLABORATIVE DESIGN OF RFID SYSTEMS FOR MULTI-PURPOSE SUPPLY CHAIN APPLICATIONS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2013年第2期22卷 152-170页

作者： Hongyan dai Jing XU School of Business Central University of Finance and Economics Department of Industrial Engineering Tsinghua University

One of the key challenges for implementing RFID systems in supply chain management is the difficulty in economic justification. Such difficulty is further amplified by its public participation nature as multiple self-interest beneficiaries may receive diverse paybacks, and their incentives to join the system are difficult to align. This paper aims to address these problems by a collaborative design from two aspects. First, we propose to introduce a centralized planning mechanism in the chain to facilitate the participation, so that the cost of the overall system can be minimized. Second, we propose to analyze the multi-facet economic return from multi-purpose applications to achieve the full potential of RFID systems. To illustrate our approach, its application for inventory inaccuracy and product recall in RFID system is presented.

关键词： RFID collaborative design economic justification centralized planning

Nonlinear dynamical behavior of Xenon atoms along dislocation lines in UO_(2+x) nuclear fuel

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2015年第5期58卷 82-87页

作者： SUI PengFei dai ZhenHong Institute of Opto-electronic Information Science and Technology Yantai University

Experimental results showed that there are a few Xenon atom bubbles connected by the dislocation line in the UO2+x nuclear fuel, and the largest radius of bubbles is about 45 nm. This phenomenon is in contrast to traditional bubble formation mechanism. This phenomenon is very important in understanding the properties of nuclear fuel. In this work, we apply a time- dependent microscopic atom transport equation and take into account stress coherent potential in the boundary of the dislocation. Using the equation, we numerically solved the stress coherence effect and studied the transfer properties of Xenon atoms along the dislocation line. Our numerical results show that the transport of the Xenon atoms along the dislocation changes nonlinearly with the external driving energy, and reaches at the saturation values. It explains the growth limit of Xenon atom bubbles that is in agreement with the experiment results.

关键词： nonlinear atom transport dislocation line nuclear fuel

COMPUTER SYSTEM FOR GEOMETRIC MODELING OF GEOLOGIC BODIES AND APPLICATIONS

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1998年第4期8卷 179-184页

作者： dai, Tagen Mao, Xiancheng Central South Univ of Technology Changsha China

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍｏｄｅｌｓｏｆｇｅｏｍｅｔｒｉｃｍｏｄｅｌｉｎｇｏｆｇｅｏｌｏｇｉｃｂｏｄｉｅｓｂｅａｒｇｅｏｍｅｔｒｉｃ，ｔｏｐｏｌｏｇｉｃａｌａｎｄａｔｔｒｉｂｕｔｅｉｎｆｏｒｍａｔｉｏｎ［１... 详细信息

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍｏｄｅｌｓｏｆｇｅｏｍｅｔｒｉｃｍｏｄｅｌｉｎｇｏｆｇｅｏｌｏｇｉｃｂｏｄｉｅｓｂｅａｒｇｅｏｍｅｔｒｉｃ，ｔｏｐｏｌｏｇｉｃａｌａｎｄａｔｔｒｉｂｕｔｅｉｎｆｏｒｍａｔｉｏｎ［１］．Ｂｙｍｅａｎｓｏｆｃｏｍｐｕｔ...

关键词： geologic body data structure mathematical model automatic plotting