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Effects of Ca substitution and surface treatment on electrochemical performances of Ml_(1.0-x) Ca_xNi_(4.0) Co_(0.6) Al_(0.4) hydrogen storage alloy electrodes

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中国有色金属学会会刊：英文版 1999年第3期9卷 487-492页

作者： Chen Weixiang(陈卫祥) 1, Qi Jianqin(祁建琴) 1, Chen Changpin(陈长聘) 2.1. department of Physics 2. department of Materials Science and {2., Zhejiang university, Hangzhou 31002., P. R. china Zhejiang Univ Dept Phys Hangzhou 310027 Peoples R China Zhejiang Univ Dept Mat Sci & Engn Hangzhou 310027 Peoples R China

The influences of Ca substitution for Ml and surface treatment on electrochemical performances of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 hydrogen storage alloy electrode were investigated. Ca substitution with x 2.for Ml could improve its discharge capacity, but Ca substitution with x >0.2.could decrease the capacity. It was also found that Ca substitution deteriorates the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. In order to improve these properties of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 alloy electrode, the alloy was treated in 6 mol/L KOH+0.02.mol/L KBH 4 solution. The results showed that the surface treatment improves the electrochemical performances such as the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. :The influences of Ca substitution for Ml and surface treatment on electrochemical performances of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 hydrogen storage alloy electrode were investigated. Ca substitution with x 2.for Ml could improve its discharge capacity, but Ca substitution with x >0.2.could decrease the capacity. It was also found that Ca substitution deteriorates the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. In order to improve these properties of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 alloy electrode, the alloy was treated in 6 mol/L KOH+0.02.mol/L KBH 4 solution. The results showed that the surface treatment improves the electrochemical performances such as the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode.

关键词： hydrogen storage alloy electrode Ca substitution surface modification

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Effect of Recycled Coarse Aggregate on Concrete Compressive Strength

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Transactions of Tianjin university 2011年第3期17卷 229-234页

作者：汪振双王立久崔正龙周梅 School of Hydraulic engineering Dalian University of Technology College of civil engineering and Architecture Liaoning Technical University

The effect of recycled coarse aggregate on concrete compressive strength was investigated based on the concrete skeleton theory. For this purpose, 30 mix proportions of concrete with target cube compressive strength ranging from 2. to 60 MPa were cast with normal coarse aggregate and recycled coarse aggregate from different strength parent concretes. Results of 2.-d test show that the strength of different types of recycled aggregate affects the concrete strength obviously. The coarse aggregate added to mortar matrix plays a skeleton role and improves its compressive strength. The skeleton effect of coarse aggregate increases with the increasing strength of coarse aggregate, and normal coarse aggregate plays the highest, whereas the lowest concrete strength occurs when using the weak recycled coarse aggregate. There is a linear relationship between the concrete strength and the corresponding mortar matrix strength. Coarse aggregate skeleton formula is established, and values from experimental tests match the derived expressions.

关键词： recycled coarse aggregate compressive strength concrete skeleton model skeleton formula crushing index

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Two-dimensional thermoelasticity solution for functionally graded thick beams

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Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 451-460页

作者： Lü Chaofeng1, CHEN Weiqiu1 & ZHONG Zheng2.1. department of civil {2., Zhejiang university, Hangzhou 31002., china 2. Key Laboratory of Solid Mechanics of Ministry of Education, School of Aerospace {2. and Ap- plied Mechanics, Tongji university, Shanghai 2.0092. china department of civil {2. Zhejiang University Hangzhou 310027 China Key Laboratory of Solid Mechanics of Ministry of Education School of Aerospace Engineering Applied Mechanics Tongji University Shanghai 200092 China

Two-dimensional thermoelasticity analysis of functionally graded thick beams is presented using the state space method coupled with the technique of differential quadrature. Material properties vary continuously and smoothly through the beam thickness, leading to variable coefficients in the state equation derived from the elasticity equations. Approximate laminate model is employed to translate the state equation into the one with constant coefficients in each layer. To avoid numerical instability, joint coupling matrices are introduced according to the continuity conditions at interfaces in the approximate model. The differential quadrature procedure is applied to discretizing the beam in the axial direction to make easy the treatment of arbitrary end conditions. A simply-supported beam with exponentially varying material properties is considered to validate the present method. Numerical examples are performed to investigate the influences of relative parameters.

关键词： state equation differential quadrature approximate laminate model joint coupling matrices thermal stresses.

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The Antifreeze Critical Strength of Low-temperature Concrete Effected by Index

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Journal of Wuhan university of Technology(Materials Science) 2011年第2期26卷 355-360页

作者：刘军 School of Material Science and engineering Shenyang Jianzhu University

The antifreeze critical strength and the pre-curing time of low-temperature concrete were studied by means of guaranteed rate of compressive strength and antifreeze performance for the structural safety requirement of concrete engineering,suffering once freeze damage under air *** is shown that the antifreeze critical strength is 3.7-4.4MPa,pre-curing time is 18-32.h by guaranteed rate of compressive strength,and the antifreeze critical strength is 3.7-4.4MPa,pre-curing time is 18-32.h by guaranteed rate of antifreeze *** can be found that the method of guaranteed rate of compressive strength is sensitive to the defect which generated by freeze damage in the concrete *** method is fit to evaluate the antifreeze critical strength of low-temperature concrete.

关键词： guaranteed rate of compressive strength guaranteed rate of antifreeze performance antifreeze critical strength once freeze under air environment

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Dynamic behavior of polymer surface and the time dependence of contact angle

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Science china Chemistry 2005年第6期48卷 553-559页

作者： WANG Xinping1, CHEN Zhifang1 & SHEN Zhiquan2.1. Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, department of Applied Chemistry, Zhejiang Institute of Science and Technology, Hangzhou 310033, china 2. department of Polymer Science and engineering, Zhejiang university, Hangzhou 31002., china 1. department of Applied Chemistry Zhejiang Institute of Science and Technology Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry 310033 Hangzhou China 2. department of Polymer Science and engineering Zhejiang University 310027 Hangzhou China

Time-dependent contact angles were measured by depositing sessile drops of wa-ter on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θ s) and equilibrium contact angles (θ e) obtained by the sessile drop method depend on polymer properties. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θ s) and equilibrium contact angles (θ e), advancing (θ a) and receding contact angles (θ r) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θ s and θ e. The results showed the linear relationships between starting (θ s) and advancing contact angles (θ a), the equilibrium (θ e) and receding contact angles (θ r). The similar relationship was also established between the contact angle hysteresis (θ a?θ r) and differences (θ s ?θ e) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the experimental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

关键词： contact angle, surface dynamic behavior, polymer surface, dynamic contact angle, time-dependence.

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A general finite element model for numerical simulation of structure dynamics

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Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 440-450页

作者： WANG Fujun1, LI Yaojun1, Han K.2.& Feng Y.T.2.1. College of Water Conservancy and civil engineering,{2. Agricultural university, Beijing 100083,{2. 2. civil & Computational engineering Centre, university of Wales Swansea, Swansea SA2.8PP, U.K. College of Water Conservancy civil engineering China Agricultural University Beijing 100083 China civil & Computational engineering Centre University of Wales Swansea Swansea SA2 8PP UK

A finite element model used to simulate the dynamics with continuum and discontinuum is presented. This new approach is conducted by constructing the general contact model. The conventional discrete element is treated as a standard finite element with one node in this new method. The one-node element has the same features as other finite elements, such as element stress and strain. Thus, a general finite element model that is consistent with the existed finite element model is set up. This new model is simple in mathematical concept and is straightforward to be combined into the existing standard finite element code. Numerical example demonstrates that this new approach is more effective to perform the dynamic process analysis in which the interactions among a large number of discrete bodies and continuum objects are included.

关键词： finite element method, discrete element method, structure dynamics, numerical simulation.

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NUMERICAL ANALYSIS OF SIDE DISCHARGES INTO A CHANNEL FLOW USING AN RNG k^(-ε)MODEL

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Journal of Hydrodynamics 1999年第3期11卷 44-54页

作者： Wang Xiao jian Cheng Liang Deparment of civil engineering, The {2. of Western Australia, Nedlands 6907, Western Australia Cui Li department of civil engineering, dalian {2. of Technology, dalian 11602., P.R.china (Received Sep.

Side discharge into a channel flow is numerically simulated using an RNG based k ε turbulence model. It is shown that the results of the recirculation zone obtained using the RNG k ε model generally agree better with the experimental results compared with those by the standard k ε model. The reason for the improvement of the results obtained using the RNG k ε model over those by the standard k ε model on this flow is analyzed. The flow at small discharge ratios is thoroughly investigated and it is found that the velocity profile at the jet exit is extremely non uniform at small discharge ratios. It is also found that the degree of the non uniformity decreases as the discharge ratio increases, and is very slight for discharge ratios larger than 2.0. The effects of calculation domain, mesh size, wall functions, bed roughness and discharge ratios on the size of separation zone are also investigated in detail.

关键词： RNG kε model side discharge flow separation zone bed roughness

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THREE-DIMENSIONAL LARGE EDDY SIMULATION OF FREE SURFACE TURBULENT FLOW IN OPEN CHANNEL WITHIN SUBMERGED VEGETATION DOMAIN

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Journal of Hydrodynamics 2003年第3期15卷 35-43页

作者： SuXiao-hui LiC.W ChenBi-hong CollegeofcivilandHydraulicengineering DalianUniversityofTechnologyDalian116024China departmentofcivilandStructural{2. HongKongPolytechnicUniversityHongKongChina

A three-dimensional Large Eddy Simulation (LES) has been performed ofhydrodynamic behavior of turbulent flow in open channel that the lower part of the domain isoccupied by a drag force layer to represent vegetation. One equation model is used to closing theresolvable scale equations. The turbulent characteristic length is parameterized by a k-l model. Aphenomenal model is employed to express the performance of vegetation in the open channel. Theresult reveals that the present model has the capacity of describing three-dimensional structure oflarge eddy appearing in turbulent flow in open channel with vegetation region and has the capacityof tracing the development of large eddies.

关键词： LES turbulent flow open channel vegetation

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On three-dimensional geological modeling and visualization

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Science china Earth Sciences 2004年第8期47卷 739-748页

作者： WU Qiang1 & XU Hua2.1. department of Resource Exploitation engineering,{2. university of Mining and Technology, Beijing 100083,{2. 2. Beijing Institute of Petrochemical Technology, Beijing 102.17,{2. 1. department of Resource Exploitation engineering China University of Mining and Technology 100083 Beijing China 2. Beijing Institute of Petrochemical Technology 102617 Beijing China

The technology of 3D geological modeling will bring about great changes in the methods of geological data acquiring, storing, processing and displaying. However, no perfect or convenient software systems have been developed up to now since the geologic data which re-flect geological entities bear the feature of diversity, uncertainty and complexity. Some supervoxel models, mathematical models of fault and geometrical models of fold have been contrived so as to show the space geometric configuration of the complicated geologic structures. The application-oriented system architecture for 3D geological modeling is established; and a novel design concept based on spatial data processing is also proposed with the technology of solid modeling as its core and the application of models as its objective. Theories and methods for 3D geological modeling will hopefully be enriched and developed. In the light of these theories and methods, a feature-based navigation visualization technique is also put forward in the paper. By integrating geo-database, graphics libraries and KBS with 3D dynamic simulation systems, geologists will be able to capture the partial characteristics and whole structure embodied in the geological data in a direct-viewing, figurative and accurate manner.

关键词： 3D geological modeling,geometrical model,system architecture,visualization

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THE　STATISTIC　CHARACTERISTICS　OF　IRREGULAR　BREAKING　WAVE　FORCES　ON　VERTICAL　WALLS

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Journal of Hydrodynamics 1995年第1期7卷 50-57页

作者： Li Yu-cheng Liu Da-zhong (Dept.of civil engineering,{2. university of Technology,{2. 11602., P. R. china) dalian Univ of Technology Dalian China

When irregular waves attack a vertical wall, standing waves and breaking (or broken) waves will occur in front of the wall. The statistic characteristics of standing wave forces on vertical wall are the same as that of incident waves. But for breaking or broken waves, only large waves break, so the statistic characteristics of breaking wave forces are different to that of standing waves or incident waves. Following a series model test of irregular breaking waves on vertical wall the statistic characterisitics of breaking wave *** were analyzed in this paper. It is found by authors that Weibul distribution may be used to express the statistic distribution of breaking wave forces acting on vertical wall. msed on the analysis of model test data, it is indicated in this paper that the shape parameter m in Weibul distribution is a function of and , in which H is the wave height, d1 is the water depth at the toe of vertical wall and d is the water depth in front of the whole structure; and the theoretical value of scale parameter a can be determined from shape parameter m.

关键词： irregular waves breaking waves wave forces vertical wall.

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