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Journal of Iron and Steel Research International 2008年第6期15卷 56-61页

作者： XIE Hao-jie WU Xiao-chun min yong-an School of Material Science and Engineering Shanghai University Shanghai 200072 China

On the basis of the uniform design method, six kinds of martensitic hot work die steels were designed. The phase transformation temperatures including Ac1 , Ac3 , and Ms were measured by DIL805A quenching dilatometer. The influences of the main elements on phase transformation temperatures were analyzed by quadratic stepwise regression analysis, and three corresponding equations were obtained. These equations, in which the interactions of the elements were considered, showed more effectiveness than the traditional ones. In addition, the thermal expansion coefficients of these steels in annealed state and quenched state were also obtained during the tests. The influences of chemical composition and temperature on the thermal expansion coefficient were analyzed; the equations obtained were verified by using several kinds of steels. The predicted values were in accordance with the results of the experiments.

关键词： phase transformation temperature thermal expansion coefficient hot work die steel uniform design quadratic stepwise regression analysis

Enhanced photocatalytic activity of nanotube-like titania by sulfuric acid treatment

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Journal of Environmental Sciences 2005年第2期17卷 290-293页

作者： YANGShao-gui QUANXie LIXin-yong FANGNing ZHANGNing ZHAOHui-min SchoolofEnvironmentalandBiologicalScienceandTechnology DalianUniversityofTechnologyDalian116024China

The TiO 2 nanotube sample was prepared via a NaOH solution in a Teflon vessel at 150℃. The as-prepared nanotubes were then treated with H 2SO 4 solutions. The TiO 2 nanotube has a crystalline structure with open-ended and multiwall morphologies. The TiO 2 nanotubes before and after surface acid treatment were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and UV-VIS dispersive energy spectrophotometry(DRS). The photocatalytic activity of the samples was evaluated by photocatalytic degradation of acid orange II in aqueous solutions. It was found that the order of photocatalytic activity was as follows: TiO 2 nanotubes treated with 1.0 mol/L H 2SO 4 solution (TiO 2(1.0M H 2SO 4) nanotubes)>TiO 2 nanotubes treated with 0.2 mol/L H 2SO 4 solution (TiO 2(0.2M H 2SO 4) nanotubes)>TiO 2 nanotubes >TiO 2 powder. This was attributed to the fact that TiO 2 nanotubes treated with H 2SO 4 was composed of smaller particles and had higher specific surface areas. Furthermore, the smaller TiO 2 particles were beneficial to the transfer and separation of photo-generated electrons and holes in the inner of and on the surface of TiO 2 particles and reduced the recombination of photo-generated electrons and holes. Acid treatment was particularly effective for TiO 2 nanotubes, this increase in activity was correlated with the concentration of H 2SO 4 solution.

关键词： titania nanotube photocatalytic activity acid orange II H 2SO 4 solutions

Super-Enrichment Mechanisms of Strategic Critical Metal Deposits:Current Understanding and Future Perspectives

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Journal of Earth Science 2023年第4期34卷 1295-1298页

作者： Shao-yong Jiang Wei Wang Hui-min Su State Key Laboratory of Geological Processes and mineral Resources Collaborative Innovation Center for Exploration of Strategic Mineral ResourcesSchool of Earth ResourcesChina University of GeosciencesWuhan 430074China

0 INTRODUCTION Critical metals are a recently proposed classification for strategic metal resources in the world. These metals are essential and critical for modern industry and economic development but face high supply risks(Hou et al., 2020). Four groups of critical metals are proposed, namely, rare metals(e. g., Li, Be, Rb, Cs, Nb, Ta, Zr, Hf, W and Sn).

关键词： metals critical rare

Effects of Cerium Doping at Ti Sites and Europium Doping at Ba Sites on Dielectric Properties of BaTiO_3 Ceramics

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Chemical Research in Chinese Universities 2006年第4期22卷 515-519页

作者： ZHANG Ya-min SUN Xiu-yun LU Da-yong College of Chemistry Jilin University Changchun 130021 P. R. China Applied Chemistry Jilin Institute of Chemical Technology Jilin 132022 P. R. China Venture Business Laboratory Department of Chemistry and Chemical Engineering Faculty of Engineering Yamagata University Yonezawa 992-8510 Japan

Two special rare earth elements cerium and europium were chosen to conduct chemical modification of the BaTiO3 structure. The cold-pressing ceramic processing technique was used to prepare barium titanate ceramics doped with Ce at Ti sites and with Eu at Ba sites on the base of formulas Ba （ Ti1 -x Cex ） O3 （x = 0. 05, 0. 10 ）（CBT） and （ Ba1-y Euy ） Ti1-x/8O3 （ y = 0. 05, 0. 10）（EBT）. Associated with structures and microstructures, the effects of cerium and europium doping on dielectric properties of BaTiO3 ceramics were discussed. The CBT ceramics exhibit a pseudocubic perovskite structure, while the EBT ceramics exhibit a tetragonal perovskite structure with the exception of the existence of a small percentage of the Eu2Ti2O7 phase. The Curie peak of BaTiO3 shifts towards room temperature at rates of 3 ℃/mol Ce atoms and 10 ℃/mol Eu atoms（ Eu≤5% ）, respectively. Compared with the CBT ceramics, the EBT ceramics show significant advantages, such as a narrow fine grain size distribution（ 1 μm）, a lower porosity and a higher density（5.85 g/cm^3）, more stable dielectric-temperature dependence（ ε′= 1600-1800 at t 〈 50℃ ） and a lower dissipation factor（〈 0. 05 ）. The stability of dielectric constant with frequency in BaTiO3 can extend to 107 Hz due to Ce and Eu doping.

关键词： Cerium Europium Barium titanate Cold-pressing technique Dielectric constant

Active Profiling and Polishing Model and Validation Based on Rotor Spiral Groove

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 198-207页

作者： Guo Yu Feng Li yong-min Yu Shou-Xiang Zai School of Earth Sciences and Resources China University of Geosciences Department of Mechanical Engineering College of Information & Business Zhongyuan University of Technology Electrical and Mechanical College Zhongyuan University of Technology Automotive Institute Henan Mechanical Electrical Secondary School

When a spiral groove is formed using superplastic molding, precision casting, additive manufacturing, or other non?mechanical processing technology, it is diffcult to meet the molding precision required for direct use, and the surface quality and accuracy of the shape need to be improved through a finishing process. In view of the poor reachability of the current tool?based polishing process, a tool?less polishing method using free?abrasive grains for complex spiral grooves is proposed. With this method, by controlling the movement of the workpiece, the design basis and relative motion of the abrasive particles along a helical path remain consistent, resulting in a better polishing profile. A spiral groove of a revolving body is taken as the research object; the influence of the installation method and the position of the parts, as well as the effect of the rotational speed of the abrasive ball on its relative motion along a helical trajectory, are studied, and the polishing cutting process of an abrasive ball is reasonably simplified. A consistent math?ematical model of the trajectory of an abrasive ball relative to the design helix is constructed. The grooved drum parts are verified through a polishing experiment. The spiral groove of the revolving body is modified and polished. Experiments show that the process not only corrects the shape a spiral groove error, but also reduces the surface roughness of a spiral groove. This study provides a theoretical basis for achieving free?abrasive, tool?free polishing.

关键词： Revolving body Spiral groove Abrasive ball Active profiling Modified and polished Model verification

Controlled Stochastic Partial Differential Equations for Rabbits on a Grassland

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 262-282页

作者： Suzanne LENHART Xiao TANG Jie XIONG Jiong-min yong Department of Mathematics University of TennesseeKnoxvilleTN 37996-1320USA Department of Mathematics.Southern University of Science and Technology Shenzhen518055China Department of Mathematics University of Central FloridaOrlandoFL 32816USA

A new approach to modeling populations incorporating stochasticity,a random environment,and individual behavior is illustrated with a specific example of two interacting populations:rabbits and *** derivation of the system of stochastic partial differential equations(SPDEs)to show how the individual mechanisms of both populations are *** model also has an unusual feature of a nonlocal *** harvesting of the rabbit population is introduced as a control variable.

关键词： Stochastic partial differential equation tightness optimal control population model

Data-driven Transient Stability Assessment Based on Kernel Regression and Distance Metric Learning

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Journal of Modern Power Systems and Clean Energy 2021年第1期9卷 27-36页

作者： Xianzhuang Liu yong min Lei Chen Xiaohua Zhang Changyou Feng the Department of Electrical Engineering Tsinghua UniversityBeijing 100084China State Grid Jibei Electric Power Company Beijing 100053China State Grid Corporation of China Beijing 100031China

Transient stability assessment(TSA) is of great importance in power systems. For a given contingency, one of the most widely-used transient stability indices is the critical clearing time(CCT), which is a function of the pre-fault power *** can be regarded as the fitting of this function with the prefault power flow as the input and the CCT as the output. In this paper, a data-driven TSA model is proposed to estimate the CCT. The model is based on Mahalanobis-kernel regression,which employs the Mahalanobis distance in the kernel regression method to formulate a better regressor. A distance metric learning approach is developed to determine the problem-specific distance for TSA, which describes the dissimilarity between two power flow scenarios. The proposed model is more accurate compared to other data-driven methods, and its accuracy can be further improved by supplementing more training ***, the model provides the probability density function of the CCT, and different estimations of CCT at different conservativeness levels. Test results verify the validity and the merits of the method.

关键词： Transient stability assessment(TSA) critical clearing time(CCT) conservativeness level distance metric learning Nadaraya-Watson kernel regression Mahalanobis distance nonparametric regression data-driven

Flow-accelerated corrosion behavior of 13Cr stainless steel in a wet gas environment containing CO_2

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International Journal of minerals,Metallurgy and Materials 2018年第7期25卷 779-787页

作者： yong Li min-dong Chen Jian-kuan Li Long-fei Song Xin Zhang Zhi-yong Liu Corrosion and Protection Centre Key Laboratory for Corrosion and Protection（MOE）National Environmental Corrosion Platform（NECP）University of Science and Technology BeijingBeijing 100083China Nuclear and Radiation Safety Center Ministry of Environmental Protection of P.R.ChinaBeijing 100082China

This work investigated the flow-accelerated corrosion （FAC） behavior of 13Cr in a wet CO2-containing environment at different flowing gas velocities mid impinging mlgles, with the natural-gas pipeline environment simulated by a self-assembled impingement jet sys- tem. Surface molphology determination, electrochemical measurements, mid hydromechaziics numerical analysis were cmlied out to study the FAC behavior. The results demonstrate that pitting corrosion was the primary mode of corrosion in 13Cr stainless steel. High-flow-rate gas destroyed the passive film mid decreased the pitting potential, resulting in more serious corrosion. The corrosion degree witk various im- pact mlgles showed the following order： 90~ 〉 60~ 〉 45~. The shear force and the electrolyte from the flowing gas were concluded to be the determinm^t factors of FAC, whereas the shear force was the main factor responsible for destroying the passive film.

关键词： flow-accelerated corrosion jet loop flowing velocity impact magle C02

Copper nanowire/multi-walled carbon nanotube com- posites as all-nanowire flexible electrode for fast-charging/ discharging lithium-ion battery

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Nano Research 2018年第2期11卷 769-779页

作者： Zhenxing Yin Sanghun Cho Duck-Jae You yong-keon ahn Jeeyoung Yoo Youn Sang Kim Program in Nano Science and Technology Graduate School of Convergence Science and Technology Seoul National University Seoul Republic of Korea Advanced Institutes of Convergence Technology Gyeonggi-do Republic of Korea

A novel lightweight three-dimensional （3D） composite anode for a fast-charging] discharging Li-ion battery （LIB） was fabricated entirely using one-dimensional （1D） nanomaterials, i.e., Cu nanowires （CuNWs） and multi-walled C nanotubes （MWCNTs）. Because of the excellent electrical conductivity, high-aspect ratio structures, and large surface areas of these nanomaterials, the CuNW-MWCNT composite （CNMC） with 3D structure provides significant advantages regarding the transport pathways for both electrons and ions. As an advanced binder-free anode, a CuNW-MWCNT composite film with a controllable thickness （~ 600 prn） exhibited a considerably low sheet resistance, and internal cell resistance. Furthermore, the random CuNW network with 3D structure acting as a rigid framework not only prevented MWCNT shrinkage and expansion due to aggregation and swelling but also minimized the effect of the volume change during the charge/discharge process. Both a half cell and a full cell of LIBs with the CNMC anode exhibited high specific capacities and Coulombic efficiendes, even at a high current. More importantly, we for the first time overcame the limitation of MWCNTs as anode materials for fast-charging]discharging LIBs （both half cells and full cells） by employing CuNWs, and the resulting anode can be applied to flexible LIBs. This innovative anode structure can lead to the development of ultrafast chargeable LIBs for electric vehides.

关键词： three-dimensional (3D)composite,all-nanowire electrode,fast chargeable batter3 fuN-cell Li-ion batteries(L1Bs),flexible battery

Syntheses of β-Hydroxy Ketones by Organosamarium

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Chemical Research in Chinese Universities 2003年第4期19卷 432-433页

作者： YU ming-xin ZHANG yong-min Department of Chemistry Zhejiang UniversityHangzhou 310027P.R.China

An organosamarium reagent was prepared via the reaction of α -bromoacetophenone with samarium. This organosamarium reagent reacted with aldehydes to give β -hydroxy ketones. A possible reaction process was... 详细信息

关键词： α-Bromoacetophenone Organosamarium reagent β -Hydroxy ketone