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Self-heating Probe Instrument and Method for Measuring High Temperature Melting Volume Change Rate of Material 被引量:2
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作者 WANG Junwei WANG Zhiping +1 位作者 LU Yang CHENG Bo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第2期371-376,共6页
The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics ... The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg/m–3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations. 展开更多
关键词 high temperature volume expansion rate molten density measuring instrument measuring method
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Synthesis of large diamond crystals containing high-nitrogen concentration at high pressure and high temperature using Ni-based solvent by temperature gradient method 被引量:1
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作者 黄国锋 贾晓鹏 +4 位作者 李尚升 张亚飞 李勇 赵明 马红安 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期662-666,共5页
This paper reprots that with Ni-based catalyst/solvent and with a dopant of NAN3, large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure ... This paper reprots that with Ni-based catalyst/solvent and with a dopant of NAN3, large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus (SPD-6 × 1200), and the highest nitrogen concentration reaches approximately 121-1257 ppm calculated by infrared absorption spectra. The synthesis conditions are about 5.5 CPa and 1240-1300 ℃. The growth behaviour of diamond with high-nitrogen concentration is investigated in detail. The results show that, with increasing the content of NaN3 added in synthesis system, the width of synthesis temperature region for growth high-quality diamonds becomes narrower, and the morphology of diamond crystal is changed from cube-octahedral to octahedral at same temperature and pressure, the crystal growth rate is slowed down, nevertheless, the nitrogen concentration doped in synthetic diamond increases. 展开更多
关键词 high temperature and high pressure nitrogen-doped diamond crystal temperature gra- dient method additive NaN3
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Modeling viscosity of methane,nitrogen,and hydrocarbon gas mixtures at ultra-high pressures and temperatures using group method of data handling and gene expression programming techniques 被引量:1
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作者 Farzaneh Rezaei Saeed Jafari +1 位作者 Abdolhossein Hemmati-Sarapardeh Amir H.Mohammadi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第4期431-445,共15页
Accurate gas viscosity determination is an important issue in the oil and gas industries.Experimental approaches for gas viscosity measurement are timeconsuming,expensive and hardly possible at high pressures and high... Accurate gas viscosity determination is an important issue in the oil and gas industries.Experimental approaches for gas viscosity measurement are timeconsuming,expensive and hardly possible at high pressures and high temperatures(HPHT).In this study,a number of correlations were developed to estimate gas viscosity by the use of group method of data handling(GMDH)type neural network and gene expression programming(GEP)techniques using a large data set containing more than 3000 experimental data points for methane,nitrogen,and hydrocarbon gas mixtures.It is worth mentioning that unlike many of viscosity correlations,the proposed ones in this study could compute gas viscosity at pressures ranging between 34 and 172 MPa and temperatures between 310 and 1300 K.Also,a comparison was performed between the results of these established models and the results of ten wellknown models reported in the literature.Average absolute relative errors of GMDH models were obtained 4.23%,0.64%,and 0.61%for hydrocarbon gas mixtures,methane,and nitrogen,respectively.In addition,graphical analyses indicate that the GMDH can predict gas viscosity with higher accuracy than GEP at HPHT conditions.Also,using leverage technique,valid,suspected and outlier data points were determined.Finally,trends of gas viscosity models at different conditions were evaluated. 展开更多
关键词 Gas Viscosity high pressure high temperature Group method of data handling Gene expression programming
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Analysis on high-temperature oxidation and growth stress of iron-based alloy using phase field method 被引量:1
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作者 杨帆 刘彬 方岱宁 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第6期757-764,共8页
High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been... High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been a challenge. In this work, a phase field method (PFM) based on the thermodynamics theory is developed to simulate the oxidation behavior and oxidation induced growth stress. It involves microstructure evolution and solves the problem of quantitatively computational analysis for the oxidation behavior and growth stress. Employing this method, the diffusion process, oxidation performance, and stress evolution axe predicted for Fe-Cr-A1-Y alloys. The numerical results agree well with the experimental data. The linear relationship between the maximum growth stress and the environment oxygen concentration is found. PFM provides a powerful tool to investigate high-temperature oxidation in complex environments. 展开更多
关键词 high-temperature OXIDATION phase field method growth stress
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Carbon spheres prepared via solvent-thermal reaction method and their microstructures after high temperature treatment
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作者 尹彩流 文国富 +3 位作者 黄启忠 王秀飞 何良明 刘宝容 《Journal of Central South University》 SCIE EI CAS 2010年第5期895-898,共4页
Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres befor... Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres before and after high temperature treatment(HTT) were characterized by X-ray diffractometry(XRD) ,scanning electronic microscopy(SEM) ,energy diffraction spectroscopy(EDS) ,and transmission electron microscopy(TEM) .The formation mechanism of carbon spheres was discussed.The results indicate that the carbon spheres convert to hollow polyhedron through HTT.Carbon spheres are composed of entangled and curve graphitic layers with short range order similar to cotton structure,and carbon polyhedron with dimension of 50-250 nm and shell thickness of 15-30 nm.The change of solid spheres to hollow polyhedron with branches gives a new evidence for formation mechanism of hollow carbon spheres. 展开更多
关键词 carbon spheres solvent-thermal method MICROSTRUCTURE high temperature treatment
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High Ferroelectricities and High Curie Temperature of BiInO3PbTiO3Thin Films Deposited by RF Magnetron Sputtering Method
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作者 孙科学 张淑仪 Kiyotaka Wasa 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第12期19-22,共4页
Properties of ferroelectric xBiInO3-(1-x)PbTiO3(xBI-(1-x)PT) thin films deposited on(101) SrRuO3/(200)Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are inve... Properties of ferroelectric xBiInO3-(1-x)PbTiO3(xBI-(1-x)PT) thin films deposited on(101) SrRuO3/(200)Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated.The structures of the xBI-(1-x)PT films are characterized by x-ray diffraction and scanning electron microscopy.The results indicate that the thin films are grown with mainly(001) orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process.The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents,2 mol% La2 O3 is doped in the targets. The P-E hysteresis loops show that the optimized xBI-(1-x)PT(x = 0.24) film has high ferroelectricities with remnant polarization2 Pr = 80μC/cm2 and coercive electric field 2 EC = 300 kV/cm. The Curie temperature is about 640℃. The results show that the films have optimum performance and will have wide applications. 展开更多
关键词 In Pb MGO high Ferroelectricities and high Curie temperature of BiInO3PbTiO3Thin Films Deposited by RF Magnetron Sputtering method
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Analysis and Forecasting Model of Durative Hightemperature in Late Spring and Early Summer in 2009 被引量:1
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作者 樊晓春 吴颖娟 +2 位作者 王妍 李彩红 党冰 《Meteorological and Environmental Research》 CAS 2010年第3期37-41,共5页
This paper analyzed characteristics of Pingliang City's continuous hot weather from late spring to early summer in 2009.The result showed that,when the daily maximum temperature in some parts of cities had run up ... This paper analyzed characteristics of Pingliang City's continuous hot weather from late spring to early summer in 2009.The result showed that,when the daily maximum temperature in some parts of cities had run up to 32℃ or above,the number of days reached the top in recent 40 years.The average temperature,average maximum temperature,surface maximum temperature and surface average temperature in most parts of the city broke history record.Based on the analysis of characteristics of the 500 hPa circulation,which resulted in durative high temperature weather,3 kinds of the high temperature circulation patterns were summarized.It was the continental warm high pressure that resulted in the durative high temperature weather in June,2009.Meanwhile,by using European numerical forecast product and MOS,the forecasting method of high temperature,from June to August,was set up.The method had been used in June,and its high-temperature forecasting accuracy in 24,48,72,96,120 hours had respectively amounted to 76.6%,69.5%,61.4%,58.1% and 51.9%. 展开更多
关键词 Lingering high temperature Circulation characteristics Forecasting method China
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Effects of a carbon convection field on large diamond growth under high-pressure high-temperature conditions 被引量:2
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作者 胡美华 李尚升 +4 位作者 马红安 宿太超 李小雷 胡强 贾晓鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第9期525-530,共6页
Large diamond crystals were successfully synthesized by a FeNi C system using the temperature gradient method under high-pressure high-temperature conditions. The assembly of the growth cell was improved and the growt... Large diamond crystals were successfully synthesized by a FeNi C system using the temperature gradient method under high-pressure high-temperature conditions. The assembly of the growth cell was improved and the growth process of diamond was investigated. Effects of the symmetry of the carbon convection field around the growing diamond crystal were investigated systematically by adjusting the position of the seed crystal in the melted catalyst/solvent. The results indicate that the morphologies and metal inclusion distributions of the synthetic diamond crystals vary obviously in both symmetric and non-symmetric carbon convection fields with temperature. Moreover, the finite element method was applied to analyze the carbon convection mode of the melted catalyst/solvent around the diamond crystal. This work is helpful for understanding the growth mechanism of diamond. 展开更多
关键词 DIAMOND high pressure and high temperature temperature gradient method carbonconvection field
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Various admixtures to mitigate the long-term strength retrogression of Portland cement cured under high pressure and high temperature conditions 被引量:2
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作者 Jiankun Qin Xueyu Pang +2 位作者 Ashok Santra Guodong Cheng Hailong Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第1期191-203,共13页
In order to investigate the problem of long-term strength retrogression in oil well cement systems exposed to high pressure and high temperature(HPHT)curing conditions,various influencing factors,including cement sour... In order to investigate the problem of long-term strength retrogression in oil well cement systems exposed to high pressure and high temperature(HPHT)curing conditions,various influencing factors,including cement sources,particle sizes of silica flour,and additions of silica fume,alumina,colloidal iron oxide and nano-graphene,were investigated.To simulate the environment of cementing geothermal wells and deep wells,cement slurries were directly cured at 50 MPa and 200?C.Mineral compositions(as determined by X-ray diffraction Rietveld refinement),water permeability,compressive strength and Young’s modulus were used to evaluate the qualities of the set cement.Short-term curing(2e30 d)test results indicated that the adoption of 6 m m ultrafine crystalline silica played the most important role in stabilizing the mechanical properties of oil well cement systems,while the addition of silica fume had a detrimental effect on strength stability.Long-term curing(2e180 d)test results indicated that nano-graphene could stabilize the Young’s modulus of oil well cement systems.However,none of the ad-mixtures studied here can completely prevent the strength retrogression phenomenon due to their inability to stop the conversion of amorphous to crystalline phases. 展开更多
关键词 high pressure and high temperature(HPHT) Strength retrogression Young’s modulus Water permeability Rietveld method
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A research on high-temperature permittivity and loss tangent of low-loss dielectric by resonant-cavity technique 被引量:1
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作者 曹茂盛 Hou Zhiling +1 位作者 Shi Xiaoling Wang Fuchi 《High Technology Letters》 EI CAS 2007年第3期279-282,共4页
Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the reson... Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors (Q) and resonant length (L) of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration. 展开更多
关键词 high temperature resonant cavity method PERMITTIVITY errors calibration
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Dissolution-precipitation mechanism of self-propagating high-temperature synthesis of TiC-Cu cermets 被引量:3
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作者 Guoqing Xiao Feng Duan +1 位作者 Gang Zhang Quncheng Fan 《Journal of University of Science and Technology Beijing》 CSCD 2007年第6期568-572,共5页
The mechanism of self-propagating high-temperature synthesis (SHS) of TiC-Cu cermets was studied using a combustion front quenching method. Microstructural evolution in the quenched sample was observed using scannin... The mechanism of self-propagating high-temperature synthesis (SHS) of TiC-Cu cermets was studied using a combustion front quenching method. Microstructural evolution in the quenched sample was observed using scanning electron microscope (SEM) with energy dispersive X-ray (EDX) spectrometry, and the combustion temperature was measured. The results showed that the combustion reaction started with local formation of Ti-Cu melt and could be described with the dissolution-precipitation mechanism, namely, Ti, Cu, and C particles dissolved into the Ti-Cu solution and TiC particles precipitated in the saturated Ti-Cu-C liquid solution. The local formation of Ti-Cu melt resulted from the solid diffusion between Ti and Cu particles. 展开更多
关键词 TiC-Cu cermet self-propagating high-temperature synthesis microstructural evolution synthesis mechanism combustion front quenching method
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Theory and Application of Numerical Simulation of Chemical Flooding in High Temperature and High Salt Reservoirs
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作者 Yirang Yuan Aijie Cheng +1 位作者 Danping Yang Changfeng Li 《International Journal of Geosciences》 2014年第9期956-970,共15页
Applications, theoretical analysis and numerical methods are introduced for the simulation of mechanical models and principles of the porous flow in high temperature, high salt, complicated geology and large-scale res... Applications, theoretical analysis and numerical methods are introduced for the simulation of mechanical models and principles of the porous flow in high temperature, high salt, complicated geology and large-scale reservoirs in this paper. Considering petroleum geology, geochemistry, computational permeation fluid mechanics and computer technology, we state the models of permeation fluid mechanics and put forward a sequence of implicit upwind difference iteration schemes based on refined fractional steps of the upstream, which can compute the pressures, the saturation and the concentrations of different chemistry components. A type of software applicable in major industries has been completed and carried out in numerical analysis and simulations of oil extraction in Shengli Oil-field, which brings huge economic benefits and social benefits. This software gives many characters: spatial steps are taken as ten meters, the number of nodes is up to hundreds of thousands and simulation time period can be tens of years and the high-order accuracy can be promised in numerical data. Precise analysis is present for simplified models of this type and that provides a tool to solve the international famous problem. 展开更多
关键词 high temperature and high SALT COMPLICATED Chemical FLOODING Computational PERMEATION Fluid Mechanics Numerical method and Engineering Software Actual Application of Oil-Fields Theoretical Analysis
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Numerical Study on the Two-Dimensional Temperature Fields of Titanium/Aluminum Double-Layer Target Irradiated by High-Intensity Pulsed Ion Beam
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作者 吴迪 雷明凯 +1 位作者 朱小鹏 宫野 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第5期581-584,共4页
Interaction between high-intensity pulsed ion beam (HIPIB) and a double-layer target with titanium film on top of aluminum substrate was simulated. The two-dimensional nonlinear thermal conduction equations, with th... Interaction between high-intensity pulsed ion beam (HIPIB) and a double-layer target with titanium film on top of aluminum substrate was simulated. The two-dimensional nonlinear thermal conduction equations, with the deposited energy in the target taken as source term, were derived and solved by finite differential method. As a result, the two-dimensional spatial and temporal evolution profiles of temperature were obtained for a titanium/aluminum double-layer target irradiated by a pulse of HIPIB. The effects of ion beam current density on the phase state of the target materials near the film and substrate interface were analyzed. Both titanium and aluminum were melted near the interface after a shot when the ion beam current density fell in the range of 100 A/cm2 to 200 A/cm2. 展开更多
关键词 high-intensity pulsed ion beam double-layer target temperature fields numerical method
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High Temperature Separation of Hydrogen from Mixture of Gases by Using Microporous Silica Membranes
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作者 Sajid Hussain Shah Yoshimitsu Uemura +1 位作者 SuzanaYusup Katsuki Kusakabe 《材料科学与工程(中英文B版)》 2011年第1期90-96,共7页
关键词 气体分离性能 二氧化硅膜 高温蒸汽 微孔 混合 化学气相沉积 分离过程
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Correlated-Electron Systems and High-Temperature Superconductivity
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作者 Takashi Yanagisawa Mitake Miyazaki Kunihiko Yamaji 《Journal of Modern Physics》 2013年第6期33-64,共32页
We present recent theoretical results on superconductivity in correlated-electron systems, especially in the two-dimensional Hubbard model and the three-band d-p model. The mechanism of superconductivity in high-tempe... We present recent theoretical results on superconductivity in correlated-electron systems, especially in the two-dimensional Hubbard model and the three-band d-p model. The mechanism of superconductivity in high-temperature superconductors has been extensively studied on the basis of various electronic models and also electron-phonon models. In this study, we investigate the properties of superconductivity in correlated-electron systems by using numerical methods such as the variational Monte Carlo method and the quantum Monte Carlomethod. The Hubbard model is one of basic models for strongly correlated electron systems, and is regarded as the model of cuprate high temperature superconductors. The d-p model is more realistic model for cuprates. The superconducting condensation energy obtained by adopting the Gutzwiller ansatz is in reasonable agreement with the condensation energy estimated for YBa2Cu3O7. We show the phase diagram of the ground state using this method. We have further investigated the stability of striped and checkerboard states in the under-doped region. Holes doped in a half-filled square lattice lead to an incommensurate spin and charge density wave. The relationship of the hole density x and incommensurability δ, δ~x, is satisfied in the lower doping region, as indicated by the variationalMonte Carlocalculations for the two-dimensional Hubbard model. A checkerboard-like charge-density modulation with a roughly period has also been observed by scanning tunneling microscopy experiments in Bi2212 and Na-CCOC compounds. We have performed a variational Monte Carlo simulation on a two-dimensional t-t′-t″- U Hubbard model with a Bi-2212 type band structure and found that the period checkerboard spin modulation, that is characterized by multi Q vectors, is indeed stabilized. We have further performed an investigation by using a quantumMonte Carlomethod, which is a numerical method that can be used to simulate the behavior of correlated electron systems. We present a new algorithm of the quantum Monte Carlo diagonalization that is a method for the evaluation of expectation value without the negative sign problem. We compute pair correlation functions and show that pair correlation is indeed enhanced with hole doping. 展开更多
关键词 high-temperature SUPERCONDUCTIVITY STRONGLY CORRELATED ELECTRONS Monte Carlo methods HUBBARD Model CONDENSATION Energy Pair-Correlation Function
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Microstructural evolution and mechanical properties of Ti-5Al-5Mo-5V-3Cr alloy by heat treatment with continuous temperature gradient 被引量:5
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作者 徐圣航 刘咏 +2 位作者 刘彬 王鑫 陈智星 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第2期273-281,共9页
A new high throughput heat-treatment method with a continuous temperature gradient between 600 and 700 ?C was utilized on the Ti-5553 alloy(Ti-5 Al-5 Mo-5 V-3 Cr, mass fraction, %). The temperature gradient was ind... A new high throughput heat-treatment method with a continuous temperature gradient between 600 and 700 ?C was utilized on the Ti-5553 alloy(Ti-5 Al-5 Mo-5 V-3 Cr, mass fraction, %). The temperature gradient was induced by the variation of the axial section of sample, which was heated by the direct current. The variation of continuous cooling rates on the treated sample was realized by using the end quenching method. The microstructural evolution and mechanical properties under different heat treatment conditions were evaluated. The results show that the pseudo-spinodal decomposition of the alloy occurs at(617±1) ?C, and the size of the precipitated α phase is around 300 nm. Moreover, the highest microhardness is obtained after the heat treatment at the pseudo-spinodal decomposition temperature for 4 h. These indicate that the high throughput method is efficient and fast to determine the phase transformation temperature and corresponding microstructural evolution of alloys. 展开更多
关键词 Ti-5Al-5Mo-5V-3Cr alloy high throughput method pseudo-spinodal decomposition temperature gradient microstructure mechanical properties
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Thyristor Junction Temperature Estimation Based on Measured Temperature of Molybdenum Flat 被引量:5
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作者 ZHANG Chunyu LI Chengrong +2 位作者 HAN Xiaohui ZHA Kunpeng TANG Guangfu 《中国电机工程学报》 EI CSCD 北大核心 2012年第22期I0026-I0026,1,共1页
为获得较准确的晶闸管结温,提出了基于晶闸管钼层实测温度计算结温的共扼梯度算法。分析了共轭梯度法用于求解结温的具体步骤,并通过FORTRAN语言编译形成LOG命令流,导入ANSYS软件中来实现算法,该方法对于未知的低频分量,以较少的迭代次... 为获得较准确的晶闸管结温,提出了基于晶闸管钼层实测温度计算结温的共扼梯度算法。分析了共轭梯度法用于求解结温的具体步骤,并通过FORTRAN语言编译形成LOG命令流,导入ANSYS软件中来实现算法,该方法对于未知的低频分量,以较少的迭代次数即可以得到准确解,对于未知的高频分量,通过多次的迭代也能够获得准确的返溯值,因而具备处理多个未知量且收敛速度快的优点。以KPD3000-72型晶闸管应用于直流输电领域为例,分别在直流稳态、单波次浪涌电流和3波次浪涌电流的试验条件下进行计算,结果表明所得结温准确,为传统热阻抗法提供了校核的依据。 展开更多
关键词 温度变化 晶闸管 结温 估计 平板 外国公司 瞬态工况 热阻抗
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Semi-analytic Solution of Steady Temperature Fields During Thin Plate Welding
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作者 DAI Yao TAN Wei +1 位作者 SUN Qi SUN Chang-qing 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2006年第B12期248-251,共4页
Usually, it is very difficult to find out an analytical solution to thermal conduction problems during high temperature welding. Therefore, as an important numerical approach, the method of lines (MOLs) is introduce... Usually, it is very difficult to find out an analytical solution to thermal conduction problems during high temperature welding. Therefore, as an important numerical approach, the method of lines (MOLs) is introduced to solve the temperature field characterized by high gradients. The basic idea of the method is to semi-discretize the governing equation of the problem into a system of ordinary differential equations (ODEs) defined on discrete lines by means of the finite difference method, by which the thermal boundary condition with high gradients are directly embodied in formulation. Thus the temperature field can be obtained by solving the ODEs. As a numerical example, the variation of an axisymmetrical temperature field along the plate thickness can be obtained. 展开更多
关键词 steady temperature field method of lines thin plate welding semi-analytic solution high gradient
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COMPARISON OF HTC METHOD AND UV/PERSULPHATE METHOD TO DETERMINE COLLOIDAL ORGANIC CARBON IN SEAWATER 被引量:2
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作者 王江涛 赵卫红 +1 位作者 谭丽菊 张正斌 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2000年第1期80-84,共5页
The application of cross flow ultrafiltration(CFF) techniques to separate colloidal organic carbon(COC) from truly dissolved organic carbon(TDOC) was investigated; COC and TDOC were determined by the high temperature ... The application of cross flow ultrafiltration(CFF) techniques to separate colloidal organic carbon(COC) from truly dissolved organic carbon(TDOC) was investigated; COC and TDOC were determined by the high temperature combustion method(HTC) and UV/persulphate method. It was found that CFF can quantitatively separate COC from seawater. The determination results by the HTC and UV/persulphate method for COC and TDOC showed little difference, which suggested that the oxidation efficiency of the two methods are identical. Colloidal particles have no remarkable influence on the oxidation efficiency of the UV/persulphate method. 展开更多
关键词 cross flow ULTRAFILTRATION COLLOIDAL organic carbon high temperature combustion method UV/persulphate method
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Preparation and properties of Ni-coated WC powder and highly impact resistant and corrosion resistant WC-Ni cemented carbides 被引量:5
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作者 Fan-lu MIN Song-bai YU +4 位作者 Sheng WANG Zhan-hu YAO Jacques Guillaume NOUDEM Si-jin LIU Jian-feng ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第6期1935-1947,共13页
WC powders were uniformly coated by Ni nanoparticles through a combined chemical co-precipitation and subsequent high temperature hydrogen reduction strategy(abbreviated as CM-WCN),and then were consolidated by vacuum... WC powders were uniformly coated by Ni nanoparticles through a combined chemical co-precipitation and subsequent high temperature hydrogen reduction strategy(abbreviated as CM-WCN),and then were consolidated by vacuum sintering at 1450°C for 1 h to obtain WC−Ni cemented carbides.The microstructure and properties of the as-consolidated CM-WCN were investigated.The average grain size of WC in the consolidated CM-WCN was calculated to be in the range of 3.0−3.8μm and only few pores were observed.A relative density of 99.6%,hardness of HRA 86.5 and bending strength of 1860 MPa were obtained for the CM-WCN−10wt.%Ni,and the highest impact toughness of 6.17 J/cm^(2 )was obtained for the CM-WCN−12wt.%Ni,surpassing those of the hand mixed WC−Ni(HM-WCN)cemented carbides examined in this study and the other similar materials in the literature.CM-WCN cemented carbides possess excellent mechanical properties,due to their highly uniform structure and low porosity that could be ascribed to the intergranular-dominated fracture mode accompanied by a large number of plastic deformation tears of the bonding phase.In addition,the corrosion resistance of CM-WCN was superior to that of HM-WCN at the Ni content of 6−12 wt.%. 展开更多
关键词 WC−Ni cemented carbides chemical co-precipitation method high temperature hydrogen reduction strategy Ni content microstructure impact toughness corrosion resistance
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