检索结果-南通市图书馆

A numerical method for spherical particle motion in turbulent flow with large Reynolds number

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1999年第4期11卷 407-414,442页

作者： ZHANG Yong\|ze\+1, LI Jia\+2. LI Ke feng\+2. WANG Xuan\+3 (1. Chinese Research Academy of Environmental Sciences, Beijing 100012. china 2. sichuan university,{2., china 3. Beijing Normal university, Beijing 100875, china) 中国环境科学院标准所北京四川大学高速水力学国家重点实验室四川成都北京师范大学环科所北京

A new mathematical model, fluctuation spectrum random trajectory model (FSRTM) for the particle motion in environmental fluid was developed using Lagrangian method, in which the time mean velocity of the fluid was calculated by a time mean velocity formula for two dimensional homogeneous shear turbulent flows in open channel, the velocity fluctuation of the fluid was determined by Fourier expansion and fluctuation spectrum, and the particle motion equation was solved using Ronge Kutta method. For comparison, the spherical cation exchange resins with a density of 1 44 g/cm\+3 and diameters ranging from 0 50—0 60 mm, 0 60—0 70 mm and 0 80—0 90 mm were selected as the experimental solid particles, and their moving velocities and trajectories in shear turbulent flows with the flow Reynolds number of 4710, 102.0, 11900 and 2.760 were investigated. The comparing analyses of the modeled results with the measured results have shown that the model developed in this paper can describe the motions of the particles in shear turbulent flow.

关键词： shear turbulent flow particle motion fluctuation spectrum random trajectory model

基于RIA和云计算的雅砻江流域梯级生态调度决策支持系统

在线全文

学校读者我要写书评

暂无评论

水电站机电技术 2011年第3期34卷 70-73,128页

作者：徐刚李绍才孙海龙三峡大学湖北宜昌443002 四川大学四川成都610065

以雅砻江流域梯级水电站群生态调度决策支持系统为背景,分析流域梯级水电站群生态调度原则,研究生态流量计算方法,建立生态调度模型,提出水电站群生态调度决策方法,探讨构建该决策系统的解决方案和关键技术。以RIA(Rich Internet Applic... 详细信息

以雅砻江流域梯级水电站群生态调度决策支持系统为背景,分析流域梯级水电站群生态调度原则,研究生态流量计算方法,建立生态调度模型,提出水电站群生态调度决策方法,探讨构建该决策系统的解决方案和关键技术。以RIA(Rich Internet Applications)为平台建立基于云计算的分布式、可扩展的生态调度决策支持系统。

关键词： RIA 云计算决策支持系统生态调度

EFFECT OF PAN-MILLING ON RHEOLOGICAL PROPERTIES OF HIGH DENSITY POLYETHYLENE

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2000年第5期18卷 397-403页

作者： Hua Huang Polymer Research Institute, sichuan university, chengdu 610065,{{2. sichuan Univ Polymer Res Inst Chengdu 610065 Peoples R China Shanghai Jiao Tong Univ Sch Chem & Chem Technol Shanghai 200240 Peoples R China

The effect of pan-milling on the rheological properties of high density polyethylene (HDPE) was studied. An innovative milling apparatus, viz. an inlaid pan-mill, was used. Melt indexer, capillary rheometer, Haake Rheocord 90 single-screw extruder and Brabender rheometer were used to evaluate the rheological properties of HDPE. HDPE with higher initial molecular weight and larger particle size was easier to degrade under pan-milling stress, as indicated by the melt index. Pressure oscillation in capillary flow occurred at significantly higher shear stress and shear rate for milled HDPE than for unmilled HDPE. The apparent shear viscosity of HDPE decreased with increasing times of milling. After milling, the flow activation energy decreased and thus the sensitivity of viscosity to temperature was reduced. Die pressure and torque during single screw extrusion were reduced significantly after milling. Plasticizing time as measured in a Brabander mixer decreased markedly with increasing milling times.

关键词： high density polyethylene rheological properties pan-milling

Theoretical analysis and experiment of micromechanics and mechanics-optics coupling of distributed optic-fiber crack sensing

在线全文

学校读者我要写书评

暂无评论

中国科学：技术科学英文版 2011年第S1期54卷 185-191页

作者： LIU HaoWu 1,2.CHEN Jiang 2.SUN Man 3 & DING Rui 2.1 State Key Laboratory of Hydraulics and Mountain River Engineering,sichuan university,{2. 610065,china 2.School of Water Resource Hydropower,sichuan university,{2. 610065,china 3 School Electrical Engineering and Information,sichuan university,{2. 610065,china sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Peoples R China sichuan Univ Sch Water Resource Hydropower Chengdu 610065 Peoples R China sichuan Univ Sch Elect Engn & Informat Chengdu 610065 Peoples R China

The micromechanical behaviors and mechanics-optics coupling effects of optic-fiber-concrete complex in the distributed optic-fiber sensing concrete-crack technology,which was used in health monitoring of Wu Gorge Bridge on Yangtze River and a large dam successfully,have been investigated.A micromechanical theoretical analysis method and micromechanical frictional contact bi-interface model,as well as a modified optical theoretical analysis method of the mechanics-optics coupling effects are presented.A series of verification experiments,including mechanical experiments and mechanics-optics coupling experiments,have been *** results of micromechanical theoretical analysis and the analysis of the modified theory of mechanics-optics coupling along with mechanical and optical experimental data are shown to be in close *** the micromechanical theory and the modified theory of mechanics-optics coupling with their analysis methods can not only enhance credibility of this novel distributed sensing technology but also provide a way to understand its sensing mechanism and optimize its technical details and system.

关键词： optic-fiber sensing mechanics-optics coupling micromechanics health monitoring concrete structure crack detection

Studies on the analytical potential energy function of diatomic molecular ion XY^+ using variational method

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第2期47卷 154-164页

作者： LIU Guoyue1,3, SUN Weiguo1,2.& FENG Hao1 1. Institute of Physics, sichuan university,{2.,{2. 2. College of Chemical Engineering, sichuan university,{2.,{2. 3. Mianyang Teacher抯 College, Mianyang 62.000,{2. Correspondence should be addressed to Sun Weiguo (e-mail: weiguosun@*** or guoyueliu@ ***) 1. Institute of Physics Sichuan University 610065 Chengdu China 2. Mianyang Teacher's College 621000 Mianyang China 3. College of Chemical Engineering Sichuan University 610065 Chengdu China

A new analytical potential energy function for diatomic molecular ion XY+ is proposed based on the energy consistent method (ECM). The Coulomb potential included in the new ionic potential contains multipole corrections, converges quickly and is variationally, changeable. The new potential and the ECM are applied to variationally studying the potential energies of eight electronic states of several diatomic molecular ions: the A2. state of CO+, the X2. g + state of Li 2.+ , the X2. g + state of He 2.+ , the 12.u state of Na 2.+ , the A2.u state of N 2.+ , the X1∑+ state of KrH+, the X2.+ state of SiO+ and the A2. state of SO+ ion. The present results agree excellently with the experiment-based Rydberg-Klein-Rees (RKR) potentials, and are superior to the commonly used Huxley-Murrell-Sorbie (HMS) analytical potentials, and are better in some cases than some quantum mechanicalab initio potentials in the ionic asymptotic and dissociation regions.

关键词： potential energy, diatomic ion, electronic state, variational method.

Diamond synthesis from a system of chromium-carbide andNi_(70)Mn_(2.)Co_5 alloy

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第24期43卷 2063-2066页

作者： LI Liangbin 1, JIANG Jinchun 1, HONG Shiming 1, ZHONG Yumao 2.and ZHANG Xinyuan 2.1. Institute of Applied Physics, {2. Union university,{2., china 2. Center for Analysis and Test, {2. Union university,{2., china Institute of Applied Physics Sichuan Union University Chengdu China Center for Analysis and Test Sichuan Union University Chengdu China

In order to ascertain the mechanism of interaction between carbide and metallic catalyst and formation of diamond under high pressure and high temperature, and find a new method to synthesize diamond with special properties, it is necessary to investigate the reaction behavior of different carbides and metallic solvent_catalysts under high pressure and high temperature. A system of Cr-3C-2.powder and Ni 70Mn 2.Co 5 alloy in weight ratio of 1∶6 was treated under 6 0 GPa and 1 500℃ for 2., 30 or 60 min respectively. X_ray diffraction of the samples indicated the Cr 3C 2.decomposed partially after high pressure and temperature treatment, and Cr 7C 3, Cr and diamond formed respectively. There was not any trace of graphite in the samples. The result suggested that the separated carbon atoms could form diamond directly without conversion process of graphite into diamond. The observation of SEI, WDX and EDX also showed that diamond crystals were synthesized in the system, which have perfect surfaces and shapes, with the average grain size of about 40 μm. The properties of the crystals are being investigated.

关键词： chromium_carbide high pressure synthesis diamond.

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_(2.molecule

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 385-398页

作者： REN Weiyi1,2. SUN Weiguo1, HOU Shilin3 & FENG Hao4 1. Institute of Physics, College of Chemical Engineering, sichuan university,{2.,{2. 2. Institute of Theoretical Physics, Xihua Normal university, Nanchong 637002.{2. 3. Department of Physics,{2. Oceanography university, Qingdao 2.6003,{2. 4. College of Physics, sichuan university,{2.,{2. 1. Institute of Physics College of Chemical Engineering Sichuan University 610065 Chengdu China 2. Institute of Theoretical Physics Xihua Normal University 637002 Nanchong China 3. Department of Physics China Oceanography University 266003 Qingdao China 4. College of Physics Sichuan University 610065 Chengdu China

It is usually very difficult to directly obtain molecular dissociation energy De and all accurate high-lying vibrational energies for most diatomic electronic states using modern experimental techniques or quantum theories, and it is also very difficult to give accurate analytical expression for diatomic molecular dissociation energy. This study proposes a new analytical formula for obtaining accurate molecular dissociation energy based on the LeRoy and Bernstein’s energy expression in dissociation limit. A set of full vibrational energy spectra for some electronic states of N2.molecule are studied using the algebraic method (AM) suggested recently, and the corresponding accurate molecular dissociation energies are evaluated using the proposed new formula and high-lying AM vibrational energies. The results show that the AM spectra and the new theoretical dissociation energies agree excellently with experimental data, and thereby providing a new physical approach to generating accurate dissociation energies for electronic states of diatomic molecules.

关键词： vibrational energy, dissociation energy, nitrogen molecule, algebraic method.

Energy-Based Prediction of Low Cycle Fatigue Life of High-Strength Structural Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 47-53页

作者： LUO Yun-rong1,2. HUANG Chong-xiang1, GUO Yi2. WANG Qing-yuan1 (1. College of Architecture and Environment,{2., chengdu 610065, {2., china 2. College of Mechanical Engineering,{2. of Science and Engineering, Zigong 643000, {2., china) [a] College of Architecture and Environment. sichuan university Chengdu 610065 Sichuan China [b] College of Mechanical Engineering. sichuan university of Science and Engineering Zigong 643000 Sichuan China

Energy-based models for predicting the low-cycle fatigue life of high-strength structural steels are presented. The models are based on energy dissipation during average of cycles, cycles to crack propagation and total cycles to failure. Plastic strain energy per cycle was determined and found as an important characteristic for initiation and propagation of fatigue cracks for high-strength structural steels. Fatigue strain-life curves were generated using plastic energy dissipation per cycle (loop area) and compared with the Coffin-Manson relation. Low cycle fatigue life was found similar from both methods. The material showed Masing-type behavior. The cyclic hysterisis energy per cycle was calculated from cyclic stress-strain parameters. The fracture surfaces of the fatigue samples were characterized by scanning electron microscope and the fracture mechanisms were discussed.

关键词： low cycle fatigue high-strength steel energy-based model fatigue life

APPLYING PPE MODEL BASED ON RAGA TO CLASSIFYAND EVALUATE SOIL GRADE

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2002年第2期12卷 136-141页

作者： FU Qiang1,2. LU Tie guang2. FU Hong2.1. College of Hydraulic Power, sichuan university, chengdu 610065, P.R.{2. 2. Northeast Agricultural university, Harbin 150030, P. R. china) College of Hydraulic Power Sichuan University Chengdu P. R. China Northeast Agricultural university Harbin P. R. China

The research of soil classification and soil grade evaluation is often based on fuzzy theory. So, the traditional method has an inevitable problem about weight matrix which given by some experts, and the final result can be influenced by artificial factors. The essentials of fuzzy synthetically judge is to handle the data of high dimension. That is to reducing the dimension number. The weight matrix in fuzzy theory is corresponding to low dimension projection value of each index. But we can′t define whether the weight matrix given by experts is the best projection value or not. So, the authors apply a new technique of falling dimension named projection pursuit to soil study, through using the improved real coding based accelerating genetic algorithm to optimize the projection direction. Thus, it can transfer multi dimension data into one dimension data, through searching for the optimum projection direction to realize the soil classification and its grade evaluation. The method can avoid the artificial disturbance, and acquire preferably effect. Thus, the paper provides a new method to the research of soil classification and grade evaluation.

关键词： RAGA PPE soil classification soil evaluation