检索结果-南通市图书馆

SONIC SPEED AND SHOCK WAVE IN HIGH VELOCITY AERATED FLOWS FROM HIGH HEAD DISCHARGE STRUCTURES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2003年第4期15卷 98-103页

作者： Dong Zhi-yong Schood of Civil and Architectural Engineering, zhejiang university of technology, Hangzhou 310014, China Schood of Civil and Architectural Engineering Zhejiang University of Technology Hangzhou 310014 China

The compressible characteristics in aerated flows at the high velocity ofabout 50m/s were analyzed. Based on the theory of compressible the relations between the sonic speedand shock wave in high-velocity aerated flow were theoretically deduced. And comparisons withmeasured data were made. The theoretical and experimental results show the sonic speed in aeratedflow is merely of the order of several-dozen meters per second, and its minimum value is only 20m/s, which is far much less than that in water or air alone. So high subsonic flow, supersonic flowand transonic flow as well as compression wave, shock wave and expansion wave similarly toaerodnamics may be produced in high velocity aerated flow at the speed of the order of 50m/s. Hencethe influences of these compressible characteristics on high head discharge structures can not beneglected, especially on super high dams over 200m high.

关键词： sonic speed shock wave aerated flow super high dam compressibility

RHOMBUS THINKING METHOD AND ITS APPLICATION IN SCHEME DESIGN

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2001年第2期14卷 156-159页

作者： Zhao Yanwei Wang Wanliang Science Research Center,zhejiang university of technology Zhang Guoxian Shanghai university 浙江工业大学科学研究中心浙江杭州上海大学上海

Rhombus thinking, a new creative thinking method,is the combination of divergent thinking process and convergent thinking process,in which qualitative analysis is carried out before quantitative analysis This method tries to solve the bottle neck problem in intelligent CAD based on the extension theory The rhombus thinking method to the scheme design of new products is applied In this process, firstly, the matter element expression for the know information are set up, and then a set of matter elements are opened up by matter elements extension method; Finally,the useful information are got by appraisal method of dependent degree It has been successfully applied to the scheme design for the cutter store of machining center Theoretical and experimental results demonstrated fhat the method is much more accurate,objective and efficient than the traditional one

关键词： Extension theory Rhombus thinking method Scheme design Artificial Intelligence

P systems based multi-objective optimization algorithm

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第4期17卷 458-465页

作者： Huang Liang, He Xiongxiong, Wang Ning and Xie Yi ( National Laboratory of Industrial Control technology, Institute of Advanced Process Control, zhejiang university, Hangzhou 310027, China zhejiang university of technology, Hangzhou 310033, China) [a]National Laboratory of Industrial Control technology Institute of Advanced Process Control Zhejiang University Hangzhou China [b]zhejiang university of technology Hangzhou China

Based on P systems, this paper proposes a new multi-objective optimization algorithm (PMOA). Similar to P systems, PMOA has a cell-like structure. The structure is dynamic and its membranes merge and divide at different stages. The key rule of a membrane is the communication rule which is derived from P systems. Mutation rules are important for the algorithm, which has different ranges of mutation in different membranes. The cooperation of the two rules contributes to the diversity of the population, the conquest of the muhimodality of objective function and the convergence of algorithm. Moreover, the unique structure divides the whole population into several sub populations, which decreases the computational complexity. Almost a dozen popular algorithms are compared using several test problems. Simulation results illustrate that the PMOA has the best performance. Its solutions are closer to the true Pareto-optimal front

关键词： P systems evolutionary algorithm multi-objective optimization Pareto optimality.

Approximate merging of multiple Bézier segments

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第6期18卷 757-762页

作者： Min Chenga,b,Guojin Wanga,* aInstitute of Computer Graphics and Image Processing,zhejiang university,Hangzhou 310027,China bCollege of Science,zhejiang university of technology,Hangzhou 310032,China Institute of Computer Graphics and Image Processing Zhejiang University Hangzhou 310027 China College of Science Zhejiang University of Technology Hangzhou 310032 China

This paper deals with the approximate merging problem of multiple adjacent Bézier curves with dierent degrees by a single Bézier curve,which is a frequently seen problem in *** unified matrix representation for precise merging is presented and the approx-imate merging curve is further derived based on matrix *** at the endpoints of curves is also discussed in the merging *** show that the method in this paper achieves satisfying merging results.

关键词： Computer-aided geometric design Bézier curve Approximate merging Matrix representation

Nonlinear properties of fractal growth of thin films at low temperature

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 2001年第2期6卷 61-67页

作者： Fengmin WU, Jiefang ZHANG, Gen BIAN and Ziqin WU Research Center of Science, zhejiang university of technology, Hangzhou 310014, China Institute of Nonlinear Physics, zhejiang Normal university, Jinhua 321004, China Shao Yifu Hospital of zhejiang Provin Research Center of Science Zhejiang University of Technology Hangzhou 310014 China Institute of Nonlinear Physics Zhejiang Normal University Jinhua 321004 China Shao Yifu Hospital of zhejiang Province Hangzhou 310005 China Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 China

Fractal growth of thin films at low temperature (75-200 K) is simulated by kinetic Monte Carlo method, using realistic growth model-Ag on Pt(111) surface and physical parameters. It is shown that the fractal growth of thin films is nonlinear, i. e., the island size S(t) grows with time t as tk ) where the growth exponent k is slightly less than 1 because of the growth competition of islands and the competition between nucleation and growth of islands. The further results indicate that the branch width of islands b increases with increasing island size S as b -Sa, where a is approximately equal to 1/3 because of the geometrical structure of the triangular substrate.

关键词： fractal growth thin film Monte Carlo method

A Microchip Tunable Blue Laser Source Based upon Cr∶LiSAF in Contact with KN Crystal

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 2002年第1期11卷 6-9页

作者： MENG Hongxiang (Dept. of Optical Engineering, zhejiang university, Hangzhou 310027, China) HE Liangfang (Dept. of Applied Physics, zhejiang university of technology, Hangzhou 310014, China) Dept. of Optical Engineering Zhejiang University Hangzhou 310027 Dept. of Applied Physics Zhejiang University ofTechnology Hangzhou 310014

In this paper, a microchip laser consisted of 2.2% doped Cr∶LiSAF crystal and NCPM KN(KNbO 3) crystal and pumped by a 679 nm laser diode is reported. The maximal output of TEM 00 4.76 mW of blue laser at 431.7 nm is obtained with the absorption power of 304.6 mW. The laser shows a threshold of 76.2 mW and slope efficiency of 2.08%. Continuous-wave tunable output is demonstrated in the blue region of 423.4～445.5 nm through only changing temperature of KN crystal controlled by PID controller.

关键词： LD pumping intracavity double Cr∶LiSAF tunable blue lasers

A Heuristic for the Job Scheduling Problem with a Common Due Window on Parallel and Non-Identical Machines

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 Systems Engineering and Electronics 2001年第2期12卷 6-11页

作者： Huang Decai College of information Engineering, zhejiang university of technology,Hangzhou 310014, P. R. China College of Information Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China

In this paper, we give a mathematical model for earliness-tardiness job scheduling problem with a common due window on parallel and non-identical machines. Because the job scheduling problem discussed in the paper contains a problem of minimizing make-span, which is NP-complete on parallel and uniform machines, a heuristic algorithm is presented to find an approximate solution for the scheduling problem after proving an important theorem. Two numerical examples illustrate that the heuristic algorithm is very useful and effective in obtaining the near-optimal solution.

关键词： Common due window Job scheduling Earliness-tardiness JIT.

ω-Gorenstein injective modules and dimensions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2011年第3期54卷 421-436页

作者： ZHU HaiYan1,2 & DING NanQing3 1Department of Mathematics, zhejiang university, zhejiang 310027, China 2Department of Mathematics, zhejiang university of technology, zhejiang 310023, China 3Department of Mathematics, Nanjing university, Nanjing 210093, China 1. Department of Mathematics Zhejiang University Zhejiang 310027 China2. Department of Mathematics Zhejiang University of Technology Zhejiang 310023 China3. Department of Mathematics Nanjing University Nanjing 210093 China

Gorenstein injective modules and dimensions have been studied extensively by many authors. In this paper, we investigate Gorenstein injective modules and dimensions relative to a Wakamatsu tilting module.

关键词： Wakamatsu tilting module ω-Gorenstein injective module ω-Gorenstein injective dimension cotilting module

Shape blending of artistic brushstroke represented by disk B-spline curves

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第12期17卷 1501-1507页

作者： Cheng Min1,2 and Wang Guojin1(1. Department of Mathematics, zhejiang university, Hangzhou 310027, China 2. Department of Mathematics, zhejiang university of technology, Hangzhou 310032, China) Department of Mathematics Zhejiang University Hangzhou 310027 China 2. Department of Mathematics Zhejiang University of Technology Hangzhou 310032 China

This paper presents an algorithm for automatically generating in-between frames of two artistic brushstrokes. The basic idea of the algorithm is to represent the two key frames of artistic brushstrokes in disk B-spline curves, and then make blending of their geometric intrinsic variables. Given two key frames of artistic brushstrokes, the skeleton curves can be obtained by certain skeleton-based techniques. After disk B-spline representation of the key frames is generated, interpolation of the intrinsic variables of the initial and the target disk B-spline curves is carried out. Examples show that this method can efficiently create in-between frames of artistic brushstrokes.

关键词： computer aided calligraphy shape blending brushstroke disk B-spline curve skeleton.