检索结果-南通市图书馆

RELATIONS BETWEEN PERFORMANCE POTENTIALS AND INFINITESIMAL REALIZATION FACTORS IN CLOSED QUEUEING NETWORKS

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2002年第4期17卷 458-464页

作者： YinBaoqun DaiGuiping XiHongsheng YangXiaoxian dept.ofAutomation Univ.ofScienceandTechnologyofChinaHefei230026China dept.ofMath. Univ.ofScienceandTechnologyofChinaHefei230026China

In this paper,the concept of the infinitesimal realization factor is extended to the parameter dependent performance functions in closed queueing networks.Then the concepts of realization matrix (its elements are called realization factors) and performance potential are introduced,and the relations between infinitesimal realization factors and these two quantities are discussed.This provides a united framework for both IPA and non IPA approaches.Finally,another physical meaning of the service rate is given.

关键词： closed queueing networks,performance function,performance potential,realization matrix,infinitesimal realization factor.

A NOVEL PARAMETER FOR EVALUATING THE FATIGUE CRACK GROWTH RATE IN CARBON STEELS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第4期14卷 271-279页

作者： X.S. Wang1), S.Q. Zhn1), N. Kawagoishi2) and H. Nisitani3) 1) Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China 2) Faculty of Engineering, Kagoshima University, Kagoshima, 890-0065, Japan dept. of Eng. Mech. Tsinghua Univ. Beijing 100084 China

A novel parameter is suggested for evaluating the fatigue crack growth rate in carbon steels. Fatigue crack propagation tests of an annealed 0.42% carbon steel were carried out under different conditions to investigate the relationship between this dominating parameter and the crack opening displacement (COD). A new equation of fatigue crack growth rate is formulated in terms of the suggested parameter. The physical meanings of the material parameters in this equation are explored experimentally. Considering the relation of crack growth and deformation properties, a simple and applicable method is proposed to evaluate the fatigue crack growth rate. It is also observed that the material parameters in the fatigue crack growth rate equation of carbon steels are related linearly to the material strength. The results are in a good agreement with experimental results.

关键词： Crack propagation Evaluation Fatigue testing Parameter estimation

Research on Water-Taking Characteristics of Huanghua Power Plant Reach

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 1998年第1期13卷 99-112页

作者： Tong, ZS Ying, XY Qian, BF Nanjing Hydraul Res Inst Dept Hydraul Engn Nanjing 210029 Peoples R China

In this paper the water-taking characteristics of the first,the second and the third stage of theHuanghua Power Plant are studied by numerical model and physical model.The results show that the pres-ent inlet channel only satisfies the supply need of the first stage of the power plant.If the riverbed of the in-let reach is properly dredged,the need of water supply for the third stage of the power plant could be met.

关键词： physical model numerical simulation cooling water tidal river

FUNDAMENTAL EQUATIONS OF TURBULENT TWO-PHASE FLOW

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 1986年第6期7卷 515-524页

作者：蔡树棠范正翘陈越南 Hangzhou Zhejiang University University of Science and Technology of China. Hefei dept. of Modern Mechanics dept. of Mechanics

A new set of Keynolds equations for predicting turbutent two-phase flows has beendeveloped by means of Reynolds averaging method on the unsteady laminar equations oftwo-phase flow.These equations involve average terms of products of turbulent fluctuationsin some physical parameters in a large degree.The interaction forces between two phases,thepressures for dispersed phase,extra stresses except for pressure and the expressions forenergy interchange between two phases have been discussed.

关键词： FUNDAMENTAL EQUATIONS OF TURBULENT TWO-PHASE FLOW

Cerebral venous thrombosis in an adult patient with nephrotic syndrome

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 Medical Journal 2014年第18期127卷 3354-3355页

作者： Wei Luhua Liu Yang Huang Yining Peking Univ Hosp 1 Dept Neurol Beijing 100034 Peoples R China

To the editor： We present a case of cerebral venous thrombosis in an adult patient with nephrotic syndrome.A 42-year-old male was admitted to Peking University First Hospital complaining of a headache for 3 days followed by clumsiness of both hands and generalized seizures. A diagnosis of nephrotic syndrome （NS） was made 1 month ago, of which the pathology was minimal change disease （Figure 1 and 2）. He was in remission and took prednisone 50 mg/d regularly. Upon physical examination, edema of bilateral lower limbs was noted, and he was comatose without other significant neurological signs. Urine protein excretion was 24.97 g/24 hours and serum albumin 26.7 g/L. Computed tomography venography of the head showed a suspicious filling defect in the superior sagittal sinus as well as subarachnoid hemorrhage.

关键词： Cerebral venous thrombosis adult patient nephrotic syndrome

GRID GENERATION AND NUMERICAL SIMULATION OF 2-D RIVER FLOW

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2001年第2期13卷 50-54页

作者： Zhao, M.D. Li, Y.T. dept. of River Eng. Wuhan Univ. Wuhan 430072 China

This paper presents new weighting functions in grid generation and new discretizing scheme of momentum equations in numerical simulation of river flow. By using the new weighting functions, the curvilinear grid could be concentrated as desired near the assigned points or lines in physical plane. By using the new discretizing scheme, the difficulties caused by movable boundary and dry riverbed can be overcome. As an application, the flow in the Wuhan Section of Yangtze River is simulated. The computational results are in good agreement with the measured results. The new method is applicable to the numerical simulation of 2-D river flow with irregular region and moveable boundary.

关键词： Computer simulation Flow of fluids Mathematical models Poisson equation Two dimensional

Spectrum Characteristics and Transfer Function of the Hydrograph of the Deep Aqueous System

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1993年第4期67卷 453-464页

作者： Chen Baoren, Liu Shuyun, Earth Sciences dept., Nanjing University, Nanjing, Jiangsu, China Jin Peikang Geological dept., Tulane University, New Orleans, LA 70118, U.S.A. and Dong Shouyu Hebei Province Seismological Bureau, Shijiazhuang, Hebei, China Earth Sciences dept Nanjing University Nanjing Jiangsu China

The fluctuation of most of the hydrograph in the deep aqueous system records the fluid pulsation in lithosphere and variation of the earth's crust. Many observations have verified that groundwater is an ideal information carrier of the crust. In this paper, the series of input (precipitation, air pressure, Earth tide etc.) and output (water level, artesian flow) of the deep aqueous system are studied by using the spectrum analysis and system theory. The application concepts of transfer function and the spectral structure of the hydrograph enrich the knowledge of the deep aqueous system. Two typical spectral structures of the hydrograph of the deep aqueous system are obtained by comparing with many water-bearing systems of the Jizhong depression. One is from well Ma-17 and the other is from the well Xinze-5. Finally, the physical models of forming the spectrum of the hydrograph are constructed on the basis of the spectrum research on the deep aqueous system.

关键词： deep aqueous system hydrograph transfer function

Modeling Study of a New Circulating Fluidized Bi-BedBoiler Combustion System

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 1999年第3期8卷 207-213页

作者： Zhao Jian Suo Yisheng Cheng Fangzhen Zhang Yong Gu Xubin(dept. of Thermal Engineering, Tsinghua University, Beijing, 100084, China) dept. of Thermal Engineering Tsinghua University Beijing China

INTRODUCTIONThecirculatingfluidizedbed(CFB)boileriscurrentlybeingactivelydevelopedinChina.AnalysisofthecharacteristicsofCFBismadetoeffectivelydesign,operateandcontroltheCFB.Mechanismanalysisandaccumulatedexperiencewer... 详细信息

关键词：流化床锅炉燃烧系统模型化

基于OpenMP的Multi-Critical分子动力学并行算法优化

在线全文

学校读者我要写书评

暂无评论

计算机应用研究 2012年第7期29卷 2432-2434页

作者：段振华白明泽豆育升重庆邮电大学高性能计算与应用研究所重庆400065 电子科技大学计算机科学与工程学院成都611731 dept.of physical Sciences Nicholls State University

为提高分子动力学模拟在多核共享内存式服务器上的运算速度,在现有的分子动力学并行算法基础上提出了Multi-Critical算法。该算法使用手动划分力矩阵的方法,使多个线程进入不同名的临界区,并使用分块叠加的方法优化了并行算法,提高了并... 详细信息

为提高分子动力学模拟在多核共享内存式服务器上的运算速度,在现有的分子动力学并行算法基础上提出了Multi-Critical算法。该算法使用手动划分力矩阵的方法,使多个线程进入不同名的临界区,并使用分块叠加的方法优化了并行算法,提高了并行效率。实验结果表明,对比之前的Critical算法,该算法的加速比和并行效率均有较大幅度的提高。

关键词：分子动力学并行计算多核处理器开放式多处理临界区