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Cooling effect of ripped-stone embankments on Qing-Tibet railway under climatic warming

Science Bulletin 2003年第6期48卷 598-604页

作者： LAI Yuanming1, ZHANG Luxin1 , ZHANG Shujuan1 & MI Long2.1. State Key Lab. of Frozen Soil engineering, Cold and Arid Regions Environmental and engineering Research {2., Chinese Academy of Sciences, Lanzhou 730000, china.2. department of civil engineering, Northern Jiaotong University, Beijing 100044, china State Key Lab. of Frozen Soil engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China department of civil {2. Northern Jiaotong University Beijing China

The heat convection in ballast mass and ripped-stone mass in railway embankments is the problem of heat convection in porous media. In order to calculate the temperature distribution of Qing-Tibet railway embankment, from the governing equations used to study forced convec-tion for incompressible fluids porous media, the finite ele-ment formulae for heat convection in porous media are de-rived by using Galerkin抯 method. The temperature fields of the traditional ballast embankment and the ripped-stone mass embankment, constructed on July 15, have been ana-lyzed and compared under the case that the air temperature in Qinghai-Tibetan Plateau will be warmed up by 2.0℃ in the future 50 years. The calculated results indicate that, the permafrost 5 m below the traditional ballast embankment will be thawed in the regions in which the air yearly-average temperature is larger than -3.5℃ or the yearly-average temperature at the native surface is larger than -1℃. The embankment will cause large thawing settlement. The rail-way embankment will be damaged by permafrost degrada-tion. The ripped-stone mass embankment can not only resist the effect of climatic warm up on it but also provide cool energy for the permafrost under it. It can assure permafrost stability and not subjected to thawing. Therefore, it is highly recommended that the ripped-stone mass embankment be taken as the Qing-Tibet railway embankment structure in high-temperature permafrost regions so that permafrost embankment can be protected as possible as we could.

关键词： cooling effect ripped-stone embankment climatic warming.

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Factors Affecting the Relation of Fracture Toughness V_(GC) with Critical Void Growth Ratio R_C/R_O

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Journal of Materials Science & technology 1998年第6期14卷 574-576页

作者： Li ZHOU(department of civil {2., Wuyi University,Jiangmen 52.02., china. department of civil {2. Wuyi University Jiangmen 529020 China

The relationship between fracture toughness VGC and critical void growth RC/RO was studied for ten kinds of Steel. The macroscopic fracture toughness VGC was determined by using notched tensile specimens. and the microscopic parameters of critical void growth ratio RC/RO were quantitatively measured under SEM. Then, the coefhcient C in the relation VGC = C In(RC/RO) proposed in author's past work was specifically explored. The correlation of C with tensile proderty parameter φ=σyδ/(Eφn) was presented for the Steel investigated, and the effects of low temperature on C were also discussed. Results show that the coefficient C is linearly related to the parameter and insensitive to low temperature.

关键词： GC with Critical Void Growth Ratio R_C/R_O Factors Affecting the Relation of Fracture Toughness V

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New Solution to Surface Temperature of Casting Slab Measurement Based on Preceded Reflector and Multi-Wavelength

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Journal of Iron and Steel Research International 2012年第8期19卷 12-16页

作者： LIU Jun1, MA Jiao-cheng2. YANG Feng3, XIAO Hui1, RAO Li-min1 (1. School of Nuclear engineering and technology, East{2.institute of technology, Fuzhou 344000, Jiangxi,{2.2. School of Mechanical engineering and Automation, Northeastern University, Shenyang 110004, Liaoning,{2.3. School of civil and Environmental engineering, East{2.institute of technology, Fuzhou 344000, Jiangxi,{2. [a] School of Nuclear engineering and technology East China Institute of Technology Fuzhou 344000 Jiangxi China [b] School of Mechanical engineering and Automation Northeastern University Shenyang 110004 Liaoning China [c] School of civil and Environmental engineering East China Institute of Technology Fuzhou 344000 Jiangxi China

The surface temperature of casting slab is an important parameter in the metallurgy field. Because the surface emissivity is uncertain and also unknown, it is difficult to measure the slab surface temperature accurately. A method based on preceded reflector and multi-wavelength was put forward to deal with the difficulty in surface temperature measurement of casting slab. On the premise of preceded reflector and non-preceded reflector, the method establishes the radiation energy equations and works out the emissivity and temperature in the equations. Also, the multilayer modeling of casting slab surface and multiple reflection-absorption process modeling were built by Monte Carlo method. The temperature measuring method had been applied in the continuous casting field. In order to verify the measured result, the thermal imaging method was adopted when the slab surface emissivity was set by repeated tests. Finally, the measured and verified temperature curves keep a same tendency and the error of the values is lower than 5℃. The comparison result shows that the method can measure temperature accurately.

关键词： casting slab emissivity surface temperature preceded reflector multi-wavelength

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VERTICAL VELOCITY DISTRIBUTION IN STEADY NON-UNIFORM AND UNSTEADY OPEN-CHANNEL FLOW

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Journal of Hydrodynamics 1997年第3期9卷 49-64页

作者： T. Song, Y. M.ChiewSchool of civil and Structural engineering, {2. Technological University, Singapore639798 nanyang Technological Univ Singapore Singapore

Based on the continuity equation, the distribution of vertical velocity in equilibrium steady non-uniform and unsteady open-channel flows were deduced theoretically. Then a recently developed Acoustic Doppler Velocity Profiler (ADVP) at the Swiss Federal institute of technology was used to measure instantaneously the flow profiles. From these measurements, the vertical velocity and the other flow parameters were obtained. Additional data measured using an Acoustic Doppler Velocimeter (ADV) at the {2. Technological University were also presented. The agreement between the theoretical distribution of vertical velocity and the measured data is reasonably good.

关键词： open-channel (flow,vertical velocity Acoustic Doppler Velocity Profiler,Acoustic Doppler Velocimeter

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Cutting Performance and Mechanism of RE Carbide Tools

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Rare Metals 2001年第3期20卷 197-201页

作者： Jianbing Cheng, Yufang Wu, Qixun Yu 1) department of Mechanical engineering, Beijing {2. and Business University, Beijing 100037, china.2. College of Mechanical engineering and Automation, Beijing institute of {2. Beijing 100081, china Beijing Technol & Business Univ Dept Mech Engn Beijing 100037 Peoples R China Beijing Inst Technol Coll Mech Engn & Automat Beijing 100081 Peoples R China

The research of rare earth elements (RE), added into cemented carbide tools, is one of the recent developments of new types of tool materials in china. Systematic experiments about RE carbides YG8R. (K30), YT14R (P2.) and, YW1R (M10) were made to study on the cutting performance in comparison with non-RE carbides YG8, YT14 and YW1. The cutting experiments were as follows: tool life, cutting force, tool-chip friction coefficient and interrupted machining. The action of RE on the carbide materials and the cutting mechanism of the RE carbide tools in the cutting process were verified with the aid of SEM and energy spectrum analysis. Experimental results show that the RE carbide tools have a good overall performance.

关键词： rare earth elements cemented carbide tool cutting performance cutting mechanism

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Early Age Compressive Strength of Pastes by Electrical Resistivity Method and Maturity Method

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Journal of Wuhan University of technology(Materials Science) 2011年第5期26卷 983-989页

作者：肖莲珍 School of Materials Science and engineering Wuhan Institute of Technology

The compressive strength development of Portland cement pastes was investigated by the electrical resistivity method and the maturity *** experiments were carried out on the cement pastes with different water-cement ratios at different curing *** results show that the application of the maturity method has limitation to obtain the *** is found that both of the compressive strength and the electrical resistivity follow hyperbolic trend for all the *** hyperbolic equation of each mix is obtained to estimate the ultimate resistivity value which can probably be *** relationship between electrical resistivity and compressive strength of the cement pastes is established based on the test results and interpreted by the empirical Archie equation and a strength-porosity *** relationship between the electrical resistivity after temperature correction and the compressive strength was linear and independent of curing temperature and water-cement ratio.

关键词： electrical resistivity cement hydration compressive strength maturity method

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Theoretical calculation of the impact work in the alloying non-quenched and tempered steel

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Science china.Technological Sciences) 2006年第3期49卷 257-273页

作者： LIU Zhilin1, LIN Cheng1 & GUO Yanchang2.1. department of Materials and Chemical engineering, Liaoning {2. of technology, Jinzhou 12.001, china.2. The Technical Center of Benxi Iron and Steel Group Corporation, Benxi 117000, china department of Materials Chemical engineering Liaoning Institute of Technology Jinzhou 121001 China The Technical Center of Benxi Iron Steel Group Corporation Benxi 117000 China

Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr, Ni, Mo, W, Cu, V, Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases, the smallest electron density difference ?ρ of phase interfaces, and the number of atom states σ (σ′) which keep the interface electron density continuous. The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms. The solution strengthening, interface strengthening, precipita- tion strengthening of pearlite, and dispersion strengthening will result in the decrease of the finishing rolling impact work; the refinement strengthening, the precipitation strength- ening of V, Nb and Ti in α-Fe-C-V(Nb, Ti), and the residual austenite containing Ni on the boundary of α-Fe-C-Ni will increase the impact work; and the increments or decrements can be calculated with nA, ?ρ, σ (σ′) and weights of alloying elements. The calculation formulas of the finishing rolling impact work in this paper are intergraded with the sug- gested ones of the finishing rolling tensile strength, yield strength, and elongation of the non-quenched and tempered steel. The calculated results agree well with the measured ones.

关键词： alloying non-quenched and tempered steel, electron structure, impact work, calculation.

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V_2._5/C catalyst for liquid phase oxidation of glyoxal to glyoxylic acid

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Science china.Chemistry 2009年第7期52卷 1057-1062页

作者： NIU YuLan1,2.& LI RuiFeng1 1 Key Laboratory of Coal Science and technology, Ministry of Education, institute of Special Chemicals, Taiyuan University of technology, Taiyuan 03002., china.2.department of Chemical engineering, Taiyuan institute of technology, Taiyuan 030008, china Key Laboratory of Coal Science and technology Ministry of Education Institute of Special Chemicals Taiyuan University of Technology Taiyuan 030024 China department of Chemical engineering Taiyuan Institute of Technology Taiyuan 030008 China

A study of the catalytic activity of V2.5/C catalyst for the oxygen oxidation of glyoxal has been made, showing that glyoxylic acid can be formed without control of pH value and there is little oxalic acid from the excessive oxidation of glyoxylic acid. The studies of XRD and TEM have shown that V2.5 diffraction peaks gradually strengthen with the increase of the content of V2.5. With the content of 3% V2.5 and the calcination temperature of 573 K, V2.5/C catalyst displayed the best activity and selectivity. The conversion of glyoxal and the selectivity of glyoxylic acid reached 18.76% and 77.70% after 5 h, respectively. Moreover, V2.5/C catalyst showed small deactivation after recycling three times, which indicates that V2.5/C has a higher stability than noble metal catalysts in the reaction medium.

关键词： glyoxal glyoxylic acid V2.5/C catalyst

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The 3-D non-axisymmetrical Lamb's problem in transversely isotropic saturated poroelastic media

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Science china.Technological Sciences) 2004年第5期47卷 526-549页

作者： HUANG Yi1 & WANG Xiaogang1,2.1. School of civil engineering, Xian University of Architecture & {2., Xian 710055, china.2. department of civil engineering, Qinghai University, Xining 810016, china.Correspondence should be addressed to Huang Yi (email: huangyih@***) Received April 15, 2.04 revised July 12. 2.04 1. School of civil engineering Xi’an University of Architecture & Technology 710055 Xi’an China 2. department of civil engineering Qinghai University 810016 Xining China

Based on Biots theory on fluid-saturated porous media, the displacement functions are adopted to convert the 3-D Biots wave equations in the cylindrical coordinate for transversely isotropic saturated poroelastic media into two棗one 6-order and one 2.order棗uncoupling differential governing equations. Then, the differential equations are solved by the Fourier expanding and Hankel integral transform method. Integral solutions of soil skeleton displacements and pore pressure as well as the total stresses for poroelastic media are obtained. Furthermore, the systematic study on Lambs problems for the transversely isotropic saturated poroelastic media is performed. Integral solutions for surface radial, vertical and circumferential displacements are obtained in both cases of drained surface and undrained surface under the vertical and horizontal harmonic excitation force. In the end of this paper, the numerical examples are presented. The calculation results indicate that the difference between the model of isotropic saturated poroelastic media and that of transversely isotropic saturated poroelastic media is obvious.

关键词： transversely isotropic saturated poroelastic media, Biot's wave equations, Lamb's problems.

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DYNAMIC STABILITY AND DEFORMATION OF OFFSHORE GRAVITY PLATFORM FOUNDATION

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china.Ocean engineering 1988年第1期2卷 31-42页

作者： Luan Maotian Jin Chongpan Doctor Candidate, civil engineering {2., Dalian institute of technology, Dalian Professor, civil engineering {2., Dalian institute of technology, Dalian Doctor Candidate Civil Eng Dept Dalian Inst of Tech Dalian PRC. China

t - The dynamic stability of the structure and deformation of marine foundation soils during storm condition or under seismic loading are of prime importance in designing offshore gravity structures. Based on limit equilibrium principle and pseudostatic concept, this paper develops a composite method for evaluating the dynamic stability of the structure foundation .subjected to such complicated loading. Moreover, computation procedures used to estimate stresses and deformations in the foundation under static and transient/eyclie loading are presented in detail. Finally, numerical results for a projected offshore gravity platform are given as examples.

关键词： DYNAMIC STABILITY AND DEFORMATION OF OFFSHORE GRAVITY PLATFORM FOUNDATION

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