检索结果-南通市图书馆

Science China(Technological Sciences) 2010年第3期53卷 782-788页

作者： XU ShuXue&MA GuoYuan beijing University of Technology,beijing 100124,China beijing University of Technology Beijing China

Ejector can utilize high pressure energy from liquid mechanism,it can be used in heat pump system coupled with economized vapor injection(EVI)scroll *** running under low temperature conditions,the performance of the EVI system with ejector can be improved *** this paper,the design method of the heat pump system with ejector is presented,and the process for designing the heat pump with ejector(EVIe)was *** prototype heat pump was designed under the condition of the evaporation temperature of -20oC,and an experimental setup was established to test the *** measured results demonstrated that the heating EER(energy efficiency ratio)of the EVIe could reach about 4%higher than that of the system without the ejector when the heating capacity remained nearly *** design method is helpful to development of a heat pump system coupled with scroll compressor and ejector.

关键词： heat pump ejector design scroll compressor

A Probe into China's Near Term Finished Petroleum Products Market

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2009年第3期11卷 1-4页

作者： Duan Yanting Yin Zhe (beijing University of Technology,beijing 100124) beijing University of Technology Beijing 100124 China

This article described the changes in consumption of finished petroleum products in China since 2008, referring to the international economic environment that has reversed the consumption of finished oil products, and China＇s domestic economic situation and oil pricing policy and major factors related with changes in industrial sectors. This article, by making projections on future market trends, has estimated that in the foreseeable future the domestic finished oil products market will be glutted with oil products that will exceed the demand.

关键词： market finished petroleum product consumption analysis

Tribological Performance of TiB_2-Ni Composite Coating Deposited by APS

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2012年第S1期41卷 481-486页

作者： Zhu Hongbin,Li Hui,Li Zhuoxin beijing University of Technology,beijing 100124,China beijing Univ Technol Beijing 100124 Peoples R China

TiB2-Ni composite powders were prepared by pressurized hydrogen reduction cladding with different proportion of *** coatings were then prepared by *** microstructures and the phase composition of the powders as well as the deposited coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The coatings were tested using a ring-on-disc tribometer from ambient temperature to 300°C.A sprayed Cr3C2-NiCr coating was tested as a *** morphologies of the worn surface of the coatings were observed and *** is found that the TiB2-Ni composite coatings present higher friction coefficient than that of the Cr3C2-NiCr coating at room temperature due to the adhesive wear mechanism,whereas the main wear mechanism of Cr3C2-NiCr coating is rupture and ***,at high temperature,the friction coefficient of the TiB2-Ni composite coating decreases as a result of B2O3 solid lubricant,which alleviates the adhesive wear on ***,the TiB2-Ni composite coating greatly reduces the mass loss of the boron cast iron.

关键词： TiB2-Ni composite coating APS wear behavior

A cross-monotonic cost sharing method for the facility location game with service installation costs

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2009年第11期52卷 2530-2536页

作者： XU DaChuan Department of Applied Mathematics,beijing University of Technology,beijing 100124,China Department of Applied Mathematics Beijing University of Technology Beijing China

In this paper,we consider the metric uncapacitated facility location game with service installation costs. Our main result is an 11-approximate cross-monotonic cost-sharing method under the assumption that the install... 详细信息

关键词： facility location game cross-monotonic cost-sharing method linear programming relaxation 90C27 91A12

Hot Deformation and Processing Maps of Al-0.3Er

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 90-94页

作者： Lin Liuqiu, Rong Li, Wang Wei, Nie Zuoren beijing University of Technology, beijing 100124, China beijing Univ Technol Beijing 100124 Peoples R China

The flow stress behavior of Al-0.3Er have been studied by hot compression tests on a Gleeble-1500D thermal simulator in the temperature range of 300-450 ℃ and strain rate range of 0.001-10 s-1. The results show that the flow stress is controlled by strain rate and deformation temperature. The flow stress decreases with deformation temperature increasing and increases with strain rate increasing. The constitutive relation of Al-0.3Er under high temperature conditions can be described by hyperbolic-sine-type equation. The processing maps based on the dynamic material model (DMM) of Al-0.3Er alloy has been also established and analyzed preliminarily. The highest efficiency of power dissipation is at the temperature range of 415-450 ℃ and in the strain rate range of 0.001-0.076 s-1 and 0.347-0.390 s-1, which is optimum working domain.

关键词： Al-Er alloy hot deformation flow stress processing maps

Convergence of Hermite interpolatory operators

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2010年第8期53卷 2115-2126页

作者： LIU YouMing & ZHAO JunJian Department of Applied Mathematics,beijing University of Technology,beijing 100124,China Department of Applied Mathematics Beijing University of Technology Beijing China

Divergence-free wavelets play important roles in both partial differential equations and fluid *** constructions of those wavelets depend usually on Hermite *** study several types of convergence of the related Hermite interpolatory operators in this *** precisely,the uniform convergence is firstly discussed in the second part;then,the third section provides the convergence in the Donoho's *** on these results,the last two parts are devoted to show the convergence in some Besov spaces,which concludes the completeness of Bittner and Urban's expansions.

关键词： Besov spaces Hermite splines convergence completeness

Finite-dimensional (*)-serial algebras

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2010年第12期53卷 3049-3056页

作者： YAO HaiLou & FAN WeiLi College of Applied Science, beijing University of Technology, beijing 100124, China College of Applied Science Beijing University of Technology Beijing China

Let A be a finite-dimensional associative algebra with identity over a field k. In this paper we introduce the concept of (*)-serial algebras which is a generalization of serial algebras. We investigate the properties of (*)-serial algebras, and we obtain suficient and necessary conditions for an associative algebra to be (*)-serial.

关键词： (*)-serial algebras biserial modules uniserial modules

Microstructure and Mechanical Properties of Magnesium Alloy AZ31B Brazed Joint Using a Zn-Mg-Al Filler Metal

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第8期26卷 743-746页

作者： Li Ma, Dingyong He, Xiaoyan Li and Jianmin Jiang College of Materials Science and Engineering, beijing University of Technology, beijing 100124, China College of Materials Science and Engineering Beijing University of Technology Beijing 100124 China

In order to join the similar magnesium alloy, a novel Zn-Mg-Al filler metal was designed and applied to braze AZ31B plates by using high-frequency induction brazing technique. The microstructure, phase constitution and fracture morphology of the brazed joint were investigated. The experimental results show that MgZn2 phase in the original filler metal is completely consumed in the brazing process. Moreover, α-Mg solid solution and α-Mg＋MgZn eutectoid structure formed in the brazing region due to the intensive alloying between the molten filler metal and the base metal in the brazing process. Test results indicate that the shear strength of the brazed joint is 56 MPa. The fracture morphology of the brazed joint shows intergranular fracture mode, where crack originates from the hard α-Mg＋MgZn eutectoid structure.

关键词： Filler metal Brazing Microstructure Mechanical properties

Nonlinear dynamics of angle-ply composite laminated thin plate with third-order shear deformation

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2010年第3期53卷 612-622页

作者： GUO Xiang Ying,ZHANG Wei & YAO MingHui College of Mechanical Engineering,beijing University of Technology,beijing 100124,China College of Mechanical Engineering Beijing University of Technology Beijing China

An asymptotic perturbation method is presented based on the Fourier expansion and temporal rescaling to investigate the nonlinear oscillations and chaotic dynamics of a simply supported angle-ply composite laminated rectangular thin plate with parametric and external *** to the Reddy's third-order plate theory,the governing equations of motion for the angle-ply composite laminated rectangular thin plate are derived by using the Hamilton's ***,the Galerkin procedure is applied to the partial differential governing equation to obtain a two-degrees-of-freedom nonlinear system including the quadratic and cubic nonlinear *** equations are utilized to deal with the resonant case of 1:1 internal resonance and primary parametric resonance-1/2 subharmonic ***,the stability analysis is given for the steady-state solutions of the averaged *** on the averaged equation obtained by the asymptotic perturbation method,the phase portrait and power spectrum are used to analyze the multi-pulse chaotic motions of the angle-ply composite laminated rectangular thin *** certain conditions the various chaotic motions of the angle-ply composite laminated rectangular thin plate are found.

关键词： angle-ply composite laminated plate third-order shear deformation theory parametric excitation chaotic motion

Analytical and experimental studies on nonlinear characteristics of an L-shape beam structure

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2010年第6期26卷 967-976页

作者： Dong-Xing Cao·Wei Zhang·Ming-Hui Yao College of Mechanical Engineering,beijing University of Technology, beijing 100124,China College of Mechanical Engineering Beijing University of Technology Beijing China

This paper focuses on theoretical and experimental investigations of planar nonlinear vibrations and chaotic dynamics of an L-shape beam structure subjected to fundamental harmonic excitation,which is composed of two beams with right-angled *** ordinary differential governing equation of motion for the L-shape beam structure with two-degree-of-freedom is firstly derived by applying the substructure synthesis method and the Lagrangian ***,the method of multiple scales is utilized to obtain a four-dimensional averaged equation of the L-shape beam *** simulations,based on the mathematical model,are presented to analyze the nonlinear responses and chaotic dynamics of the L-shape beam *** bifurcation diagram,phase portrait,amplitude spectrum and Poincare map are plotted to illustrate the periodic and chaotic motions of the L-shape beam *** existence of the Shilnikov type multi-pulse chaotic motion is also observed from the numerical ***, experimental investigations of the L-shape beam structure are performed,and there is a qualitative agreement between the numerical and experimental *** is also shown that out-of-plane motion may appear intuitively.

关键词： Multi-beam Structure Bifurcation Chaos Experiment