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BASIC THEORY AND METHOD OF WELDING ARC SPECTRAL INFORMATION

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Chinese Journal of Mechanical Engineering 2004年第2期17卷 315-318页

作者： Li Junyue Li Zhiyong Li Huan Xue Haitao School of Material Science and Engineering,tianjin University,tianjin 300072, china School of Material Science and Engineering Tianjin University 天津 300072

Arc spectral information is a rising information source which can solve manyproblems that can not be done with arc electric information and other arc information. It is ofimportant significance to develop automatic control technique of welding process. The basic theoryand methods on it play an important role in expounding and applying arc spectral information. Usingconcerned equation in plasma physics and spectrum theory, a system of equations including 12equations which serve as basic theory of arc spectral information is set up. Through analyzing ofthe 12 equations, a basic view that arc spectral information is the reflection of arc state andstate variation, and is the most abundant information resource reflecting welding arc process isdrawn. Furthermore, based on the basic theory, the basic methods of test and control of arc spectralinformation and points out some applications of it are discussesed.

关键词： Arc Plasma Spectral information Welding Automatic controls

Data fusion based on fuzzy measures

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Progress in Natural Science:Materials International 2007年第8期17卷 962-970页

作者： Yue Shihong~(**) Li Yi Liu Zhengguang Wang Ping Liu Piaoyu (School of Electronic Engineering and Automation,tianjin University,tianjin 300072,china) School of Electronic Engineering and Automation Tianjin University Tianjin 300072 China

Choquet integral based on fuzzy measure is a very popular data fusion approach.A major problem in applying the Cho- quet integral is how to determine a large number of fuzzy measures as the number of attributes ***λ-fuzzy measure proposed by Sngeno is a powerful method to resolve this ***,the modeling ability of theλ-fuzzy measure is too limited to satisfy actual *** this paper,an extendedλ-fuzzy measure is proposed using Shapley value index,and the limitation of theλ-fuzzy measure is significantly overcome under little additional computational *** extended fuzzy measure has stronger modeling power than theλ- fuzzy measure,straightforwardly representing interaction among *** apply the extended fuzzy measure to an artificial data set and a real dataset in an iron-steel *** results verify the usefulness of the extended fuzzy measure compared with other main existing methods.

关键词： data fusion Cboquet integral Shapley value index fuzzy measure

Conversion of Methane to C_2 Hydrocarbons via Cold Plasma Reaction

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Journal of Natural Gas Chemistry 2003年第3期12卷 178-182页

作者： Baowei Wang, Genhui XuSchool of Chemical Engineering and Technology, tianjin University, tianjin 300072, china Sch. Chemical Engineering/Technology Tianjin University Tianjin 300072 China

Direct conversion of methane to C_2 hydrocarbons via cold plasma reactionwith catalysts has been studied at room temperature and atmospheric pressure. Methane can beconverted into C_2 hydrocarbons in different selectivity depending on the form of the reactor, powerof plasma, flow rate of methane, ratio of N_2/CH_4 and nature of the catalysts. The selectivity toC_2 hydrocarbons can reach as high as 98.64%, and the conversion of methane as high as 60% and theyield of C_2 hydrocarbons as high as 50% are obtained. Coking can be minimized under the conditionsof: proper selection of the catalysts, appropriate high flow rate of inlet methane and suitableratio of N_2 to CH_4. The catalyst surface provides active sites for radical recombination.

关键词： methane C_2 hydrocarbons cold plasma catalyst

Surface Motion of Alluvial Valley in Layered Half-Space for Incident Plane P-Waves

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Transactions of tianjin University 2011年第3期17卷 157-165页

作者：巴振宁梁建文 School of Civil Engineering Tianjin University Key Laboratory of Coast Civil Structure Safety of Ministry of Education

The indirect boundary element method (IBEM) is used to study the surface motion of an alluvial valley in layered half-space for incident plane P-waves based on Wolf’s theory. Firstly, the free field response can be solved by the direct stiffness method, and the scattering wave response is calculated by Green’s functions of distributed loads acting on inclined lines in a layered half-space. The method is verified by comparing its results with literature and numerical analyses are performed by taking the amplification of incident plane P-waves by an alluvial valley in one soil layer resting on bedrock as an example. The results show that there exist distinct differences between the wave amplification by an alluvial valley embedded in layered half-space and that in homogeneous half-space and there is interaction between the valley and the soil layer. The amplitudes are relatively large when incident frequencies are close to the soil layer’s resonant frequencies.

关键词： layered half-space alluvial valley plane P-waves scattering one layer over bedrock indirect boundaryelement method

A PREDICTIVE MODEL FOR LONG-TERM SHORELINE CHANGE

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Journal of Hydrodynamics 1999年第1期11卷 56-63页

作者： Li Shao-wu (Department of Harbor and coastal Engineering, Civil Engineering School, tianjin Universi-ty, tianjin 300072, P. R. china) tianjin Univ Tianjin China

In this paper a predictive model for long-term shoreline change is proposed on the basis of a numerical model of wave-induced current, which is applicable to rather complex boundary conditions in nearshore region, and a one-line model of shoreline change. As a computational example, the model is used in the prediction of shoreline change of the Nouakchott coast of Mauritania and consistent results between computation and measurements are obtained.

关键词： predictive model shoreline change

Study on Calibration Methods of Structured Light Sensor

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Chinese Journal of Lasers 2002年第3期11卷 39-45页

作者： WANG Baoguang HE Zhonghai LIAO Yibai CHEN Lincai (State Key Laboratory of Precision Measuring Technology and Instruments, tianjin University, tianjin 300072, china) tianjin University State Key Laboratory of Precision Measuring Technology and Instruments 天津 300072

In this paper, advantages and disadvantages of existing calibration methods are presented. Based on the projective transformation which is the basic principle of a CCD camera, a new method of calibrating structured li... 详细信息

关键词： structured light sensor projective transformation calibration

Catalytic Preparation of Optically Active 1,1′-Binaphthalene-2,2′-Diol by Chiral Benzoimidazole-Cu(Ⅱ) Complex

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催化学报 2003年第6期24卷 401-402页

作者： YANG Qichao, ZHANG Mingjie, MA Penggao (Department of Chemistry, School of Science, tianjin University, tianjin 300072, china) Department of Chemistry School of Science Tianjin University 天津 300072

In the past several decades, much attention has been paid to optically active, C_2-asymmetric 1, 1'-binaphthalene-2, 2'-diol and its derivatives because of their application in inducing chirality in asymmetric synthesis. Enantiomerically pure 1, 1'-binaphthalene-2, 2'-diol has been prepared by many methods ranging from the classical resolution via crystallization of the diastereoisomeric salts to asymmetric oxidative coupling. However, the use of expensive chiral reagents and the tediousness of the processes set a limit on the use of those methods. Takemoto et al have reported a novel method for the asymmetric oxidative coupling of 2-naphthol with moderate chemical and optical yield, using Camellia sinensis cell culture optically active S-(-1)-1, 1'-binaphthalene-2, 2'diol by CuCl_2-mediated asymmetric oxidative coupling in the presence of (-) α-methylbenzymlamine with up to 80.6/5 e.e. In addition, Luo et al have developed the most enantioselectrive catalytic oxidative coupling of 2-naphthol using a series of novel achiral biphenol-derived diastereomeric oxovanadium (IV) complexes that have 90%～97% e.e. and high yields.

关键词：手性苯并吡咯铜(Ⅱ)配合物合成催化反应光学作用 1,1′-联二苯-2,2′-二醇催化剂不均匀氧化偶合

Non-interior Continuation Algorithm for Solving System of Inequalities over Symmetric Cones

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Transactions of tianjin University 2011年第2期17卷 89-95页

作者：张颖卢楠 School of Sciences Tianjin University

As a basic mathematical structure,the system of inequalities over symmetric cones and its solution can provide an effective method for solving the startup problem of interior point method which is used to solve many optimization *** this paper,a non-interior continuation algorithm is proposed for solving the system of inequalities under the order induced by a symmetric *** is shown that the proposed algorithm is globally convergent and ***,it can start from any point and only needs to solve one system of linear equations at most at each *** suitable assumptions,global linear and local quadratic convergence is established with Euclidean Jordan *** results indicate that the algorithm is *** systems of random linear inequalities were tested over the second-order cones with sizes of 10,100,,1 000 respectively and the problems of each size were generated randomly for 10 *** average iterative numbers show that the proposed algorithm can generate a solution at one step for solving the given linear class of problems with random *** seems possible that the continuation algorithm can solve larger scale systems of linear inequalities over the secondorder cones ***,a system of nonlinear inequalities was also tested over Cartesian product of two simple second-order cones,and numerical results indicate that the proposed algorithm can deal with the nonlinear cases.

关键词： system of inequalities symmetric cone non-interior continuation algorithm global linear convergence local quadratic convergence

Influence of moisture content and time on the mechanical behavior of polymer material

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Science china(Technological Sciences) 2004年第5期47卷 595-607页

作者： ZHENG Gaofei1, 2, KANG Yilan1, SHENG Jing3, QIN Qinghua1, WANG Huaiwen1 & FU Donghui1 1. Department of Mechanics, tianjin University, tianjin 300072, china 2. Department of Mechanics, tianjin Polytechnic University, tianjin 300160, china 3. Department of Material Engineering, tianjin University, tianjin 300072, china Correspondence should be addressed to Kang Yilan Department of Mechanics Tianjin University

The effects of moisture content and time on mechanical behavior of polymer materials are investigated both theoretically and experimentally in this paper. An equivalence relationship between time intervals and the moisture content for polymer nylon-6 has been established by way of experimental observation and measured results. The relationship shows that there exists equivalence between moisture and service time in affecting mechanical properties. In other words, an increase in moisture can be replaced by prolonging acting time in producing the same effect on material properties. Consequently, a moisture-time superposition principle is presented based on the experimental results and the analogy of temperature-time superposition principle. Numerical results such as stress-strain curves with different moisture contents are presented to verify the applicability and correctness. The proposed method appears very promising in study on the effect of moisture content on mechanical behavior of polymer materials.

关键词： equivalence relationship of moisture-time, moisture content, mechanical properties, shift function.