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A Novel Alkaloid from Stemona parviflora

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Chinese Chemical Letters 2003年第2期14卷 173-175页

作者： chang Qing Zhi sheng HE 等 StateKeylaboratoryofDrugResearch ShanghaiInstituteofmateriaMedicaShanghaiInstitutesforBiologicalSciencesChineseAcademyofSciencesShanghai200031 StateKeylaboratoryofDrugResearc

A novel alkaloid was isolated from the stems and leaves of Stemona parviflora Wright. Based on the spectral methods, its structure was elucidated as parvineostemonine.

关键词： Stemona parviflora perhydroazaazulene parvineostemonine.

A MICROSTRUCTURE-BASED ANALYSIS FOR CYCLIC PLASTICITY OF DUAL-PHASE PEARLITIC RAIL STEELS

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Acta Mechanica Solida Sinica 2001年第4期14卷 334-343页

作者： peng Xianghe chang Jian Chongqing Univ Dept Engn Mech Chongqing 400044 Peoples R China

Based on the assumption that a representative element of apearlitic steel is an aggregate of numerous spherical pearliticcolonies with randomly distributed orientations, and that each colonyis com- posed of many parallel fine lamellas of ferrite andcementite, a description for the dual-phase pearlitic steel isobtained by making use of a microstructure-based constitutiveequation for a single dual-phase pearlitic colony and the Hill'sself-consistent scheme. The elastoplastic response of dual-phasepearlitic steel BS11 subjected to asymmetrically cyclic loading isanalyzed, and a comparison with the experimental results showssatisfacto- ry agreement. The non-proportional cyclic plasticity ofBS11 is also analyzed, in which stress develops along a semi-circlein a biaxial tension/compression and shear stress plane, as istypically experienced by the sur- face elements in rolling andsliding contact.

关键词： pearlitic steel lamellar dual-phase material Hill's self-consistent scheme cyclic plasticity

New numerical solution for self-acting gas journal bearings

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第5期10卷 685-690页

作者： Hai-jun ZHANG chang-sheng ZHU Qin YANG College of Electrical Engineering Zhejiang University Hangzhou 310027 China College of Mechanical and Electrical Engineering Jiaxing University Jiaxing 314001 China

Taking a small pressure change in the gas film of self-acting gas-lubricated journal bearings into account, the corresponding nonlinear Reynolds equation is linearized through appropriate approximation and a modified Reynolds equation is derived and solved by means of the finite difference method (FDM). The gas film pressure distribution of a self-acting gas-lubricated journal bearing is attained and the load capacity is calculated. The numerical solution has a better agreement with experimental data than a direct numerical solution for different values of the bearing number. It is of interest to note that the eccentricity ratio, at which the new numerical solution is in better agreement with experimental data, is different when the bearing number is changing. The new numerical solution is slightly larger when the eccentricity ratio is smaller, and becomes slightly smaller when the eccentricity ratio is larger.

关键词： Self-acting gas journal bearings Reynolds equation Nonlinearity Finite difference method (FDM)

DFT Studies on Hydrogen Overfall Mechanism for Catalyzed Hydroisomerization of Pentane

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Chinese Journal of Structural Chemistry 2007年第2期26卷 239-247页

作者： AI Chun-Zhi SUN Ren-An WANG chang-sheng College of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116029 China Dalian Institute of Chemical Physics The Chinese Academy of Sciences Dalian 116021 China

The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and verified by the vibration frequency analysis as well as the calculations of intrinsic reaction coordinates （IRC）. Furthermore, the related reaction barriers were evaluated by single point energy at the MP2/6-311＋＋G^＊＊ level with zero point vibration correction of DFT method. Thus, it is concluded that the isomerization might go through two pathways.

关键词： catalyzed isomerization of n-pentane hydrogen overfall mechanism i-pentane DFT

Mechanical properties and energy absorption of extruded Mg–2.0Zn–0.3Zr alloy with Y addition

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Rare Metals 2015年第5期34卷 314-323页

作者： Bin-Jiang Lv Jian peng Yi peng Ai-Tao Tang Fu-sheng Pan College of Materials Science and Engineering Chongqing University Chongqing Advanced Materials Research Center Chongqing Academy of Science and Technology

The effects of the rare earth element Y addition on mechanical properties and energy absorption of a low Zn content Mg-Zn-Zr system alloy and the deformation temperature of optimized alloy were investigated by room tensile test, optical microscopy （OM）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and transmission electron microscope （TEM）. The results show that, after homogenization at 420℃ for 12 h for the as-cast alloys, MgZn phase forms, which decreases the strength of Mg-2.0Zn-0.3Zr alloy with Y content of 0.9 wt%. The tensile strength and elongation of the alloy with a Y addition of 5.8 wt% reach the max value （281 ±2） MPa and （30.1 ± 0.7） %, respectively; the strength and elongation of Mg-2.0Zn-0.3Zr-0.9Y alloy at the optimized extrusion temperature of 330 ℃ reach （321 ± 1） MPa and （21.9 ± 0.7） %, respectively. The energy absorption increases with the increase of Y content, the max value reached 0.79 MJ·m^-3 with Y content of 5.8 wt%, and the energy absorption of Mg-2.0Zn-0.3Zr-0.9Y alloy at the optimized extrusion temperature of 330 ℃ reaches 0.75 MJ·m^-3.

关键词： Yttrium Microstructure Mechanical properties Energy absorption

Phase Selection and Microstructure Evolution Dependance on Composition for Zr-Fe Eutectic Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第10期37卷 1689-1702页

作者： Dong-Dong Zuo Jian chang Hai-peng Wang School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an710072China

The knowledge of the phase selection and microstructure evolution of Zr-Fe eutectic alloys is still poorly *** presumed eutectic alloy with a nominal composition of Zr76.0Fe24.0 was discovered to contain a significant proportion ofα-Zr ***,phase selection and microstructure evolution dependance on composition for Zr-Fe eutectic alloys was experimentally determined by using differential scanning calorimetry(DSC)and meticulous electron *** alloys,spanning the composition range of 73.5-74.7%Zr,were examined to investigate microstructure evolution and non-isothermal crystallization *** indicate that in alloys ranging from Zr_(73.5)Fe_(26.5) to Zr_(73.9)Fe_(26.1),the primary FeZr_(2) phase demonstrates preferential growth,followed by eutectic microstructure formation during liquid alloy *** volume fraction of FeZr_(2) dendrites decreases as the Zr content ***,in alloys ranging from Zr_(74.0)Fe_(26.0) to Zr_(74.7)Fe_(25.3),primaryβ-Zr dendrites preferentially grow,followed by a eutectic reaction in the remaining liquid *** content ofα-Zr dendrites reduces with decreasing Zr *** mentioned above,a critical composition range for phase selection is defined as Zr_(x)Fe100.0−x(73.9

关键词： Phase selection Thermal analysis Microstructure evolution Crystallization kinetic

N-doped carbon dots coupled NiFe-LDH hybrids for robust electrocatalytic alkaline water and seawater oxidation

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Nano Research 2022年第8期15卷 7063-7070页

作者： peng Ding Haoqiang Song Jiangwei chang Siyu Lu Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450000China

Electrolysis of seawater offers a highly promising and sustainable route to attain carbon-neutral hydrogen energy without demanding on high-purity water ***,it is severely limited by the undesirable chlorine oxidation reaction(ClOR)on the anode and the releasing toxic chlorine species,inducing anode corrosion and multiple pollutions to reduce the efficiency and sustainability of this *** effective way is to limit the overpotential of oxygen evolution reaction(OER)below 480 mV and thus suppress the ***,we demonstrate that nitrogen-doped carbon dots strongly coupled NiFe layered double hydroxide nanosheet arrays on Ni foam(N-CDs/NiFe-LDH/NF)can efficiently facilitate OER with an ultralow overpotential of 260 mV to deliver the geometric current density of 100 mA·cm^(−2)and a Tafel slope of as low as 43.4 mV·dec−1 in 1.0 M *** importantly,the N-CDs/NiFe-LDH/NF electrode at 100 mA·cm^(−2)shows overpotentials of 285 and 273 mV,respectively,by utilizing 1.0 M KOH with 0.5 M NaCl and 1.0 M KOH with 1.0 M NaCl as the simulated seawater,well avoid triggering ***,despite the complex environment of real seawater,N-CDs/NiFe-LDH/NF still effectively promotes alkaline seawater(1.0 M KOH+seawater)electrolysis with a lifetime longer than 50 and 20 h,respectively,in 1.0 M KOH and alkaline seawater *** investigation result reveals that M–N–C bonding generated between N-CDs and NiFe-LDH intrinsically optimizes the charge transfer efficiency,further promoting the OER kinetics.

关键词： N-doped carbon dots electrocatalysis oxygen evolution reaction(OER) seawater oxidation chlorine oxidation reaction(ClOR)

RESEARCH ON WAVE FORCES ACTING ON THE UNIT LENGTH OF A VERITICAL BREAKWATER BY TESTS AND A NUMERICAL MODEL

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Journal of Hydrodynamics 2006年第5期18卷 512-519页

作者： HU Jin-peng YU Yu-xiu ZHU Liang-sheng LED South China Sea Institute Oceanology Chinese Academy of Sciences Guangzhou 510301 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China Graduate School of the Chinese Academyof Sciences Beijing 100049China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

Comprehensive 3D model tests and numerical simulation were performed to study the effects of wave obliquity and multidirectionality on the wave forces acting on vertical breakwaters. The variation of wave forces acting on the unit length of a breakwater was analyzed, and the results were compared with Goda＇s formula. A numerical model based on a short-crest wave system was used to model regular wave forces for practical use, which showed good results for those waves with small incident angles.

关键词： vertical breakwater uni- and multidirectional irregular waves wave forces acting on the unit length short-crest wave model

Secondary solar heat gain modelling of spectral-selective glazing based on dynamic solar radiation spectrum

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Building Simulation 2023年第12期16卷 2211-2224页

作者： peng Xue Yi Shen sheng Ye Jinqing peng Yanyun Zhang Qianqian Zhang Yuying Sun Beijing Key Laboratory of Green Built Environment and Energy Efficient Technology Beijing University of TechnologyBeijing 100124China Faculty of Architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China State Grid Zhongxing CO. LTDLvyuan BranchBeijing 100761China College of Civil Engineering Hunan UniversityChangsha 410082HunanChina Key Laboratory for New Functional Materials of Ministry of Education Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

The secondary solar heat gain,defined as the heat flows from glazing to indoor environment through longwave radiation and convection,grows with the increasing of glazing *** the rapid development and application of spectrally selective glazing,the secondary solar heat gain becomes the main way of glazing heat transfer and biggest proportion,and indicates it should not be simplified calculated ***,a dynamic secondary solar heat gain model is developed with electrochromic glazing system in this study,taking into account with three key aspects,namely,optical model,heat transfer model,and outdoor radiation *** with the traditional K-Sc model,this new model is verified by on-site experimental measurements with dynamic outdoor spectrum and *** verification results show that the root mean square errors of the interior and exterior glass surface temperature are 3.25°C and 3.33°C,respectively,and the relative error is less than 10.37%.The root mean square error of the secondary heat gain is 13.15 W/m2,and the dynamic maximum relative error is only 13.2%.The simulated and measured results have a good *** addition,the new model is further extended to reveal the variation characteristics of secondary solar heat gain under different application conditions(including orientations,locations,EC film thicknesses and weather conditions).In summary,based on the outdoor spectrum and window spectral characteristics,the new model can accurately calculate the increasing secondary solar heat gain in real time,caused by spectrally selective windows,and will provide a computational basis for the evaluation and development of spectrally selective glazing materials.

关键词： econdary solar heat gain spectral-selective glazing solar spectrum dynamic heat transfer