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A New Pregnane Glycoside from Fermented Leaves of Agave americana

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Chinese Chemical Letters 2002年第12期13卷 1189-1192页

作者： Jian Ming jin Xi Kui LIU Chong Ren YANG State Key Laboratory of Phytochemistry and Plant Resources of West China Kunming Institute of BotanyChinese Academy of SciencesKunming 650204

A new minor pregnane glycoside was isolated from the fermented leaves of Agave americana. Its structure was elucidated as (20S)-5a-pregnane-3? 20-diol 20-O--D-glucopyrano- side (1) by spectral methods.

关键词： Agave americana L. pregnane glycoside.

Asymmetric breakup of a droplet in an axisymmetric extensional flow

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Chinese Journal of Chemical Engineering 2016年第1期24卷 63-70页

作者： Dongming Yu Manman Zheng Taoming jin jingtao Wang School of Chemical Engineering and Technology Tianjin University Sinopec Shanghai Engineering Co. Ltd.

The asymmetric breakups of a droplet in an axisymmetric cross-like microfluidic device are investigated by using a three-dimensional volume of fluid(VOF) multiphase numerical model. Two kinds of asymmetries(droplet location deviation from the symmetric geometry center and different flow rates at two symmetric outlets) generate asymmetric flow fields near the droplet, which results in the asymmetric breakup of the latter. Four typical breakup regimes(no breakup, one-side breakup, retraction breakup and direct breakup) have been *** regime maps are plotted to describe the transition from one regime to another for the two types of different asymmetries, respectively. A power law model, which is based on the three critical factors(the capillary number,the asymmetry of flow fields and the initial volume ratio), is employed to predict the volume ratio of the two unequal daughter droplets generated in the direct breakup. The influences of capillary numbers and the asymmetries have been studied systematically in this paper. The larger the asymmetry is, the bigger the oneside breakup zone is. The larger the capillary number is, the more possible the breakup is in the direct breakup zone. When the radius of the initial droplet is 20 μm, the critical capillary numbers are 0.122, 0.128, 0.145,0.165, 0.192 and 0.226 for flow asymmetry factor AS= 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5, respectively, in the flow system whose asymmetry is generated by location deviations. In the flow system whose asymmetry is generated by two different flow rates at two outlets, the critical capillary numbers are 0.121, 0.133, 0.145, 0.156 and 0.167 for AS= 1/21, 3/23, 1/5, 7/27 and 9/29, respectively.

关键词： Asymmetric breakup Droplet Volume of fluid method Axisymmetric extensional flow

A Review of Research on Galvanic Corrosion of Aluminum Alloys

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Fluid Dynamics & Materials Processing 2023年第7期19卷 1907-1923页

作者： Huixin Zhu Mingzhe Leng Guofeng jin Heyang Miao Xi’an Institute of High Technology Xi’an710038China

When aluminum alloys are coupled with dissimilar materials,they often act as corrosion anodes and are suscepted to accelerated ***,deepening our knowledge of such corrosion phenomena,related mechanisms,and elaborating new prediction model is of great theoretical and practical *** this paper,such mechanisms are explained from both macroscopic and microscopic points of view by considering several aspects such as the second phase particle type,grain size,and environmental *** specifically,different perspectives on such a problem are elaborated,which take into account:the properties of the coupling pair materials,geometrical characteristics,environmental media characteristics,the corrosion regularity of different types of aluminum alloys,the influence of area ratio on anode corrosion current density,the interference of the solution primary ions represented by Cl-and the accompanying ions represented by Al3+.A review is also conducted of the standard test methods used in the study of aluminum alloys galvanic corrosion and of research methods such as the Wire Beam Electrodes Technology(WBE),the Scanning Kelvin Probe Force Microscopy(SKPFM)***,three kinds of inhibition technologies are discussed,including the anodic oxidation treatment,the corrosion inhibitor treatment and the coating protection method.

关键词： Aluminum alloy microgalvanic corrosion influencing factors first principles calculations

Open Winding-permanent Magnet/Magnet Reluctance Hybrid Rotor Double Stator Synchronous Motor SVPWM Control

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CES Transactions on Electrical Machines and Systems 2024年第4期8卷 426-435页

作者： Yufeng Pang Shi jin Wuhen jin Siyang Yu Shenyang University of Technology Shenyang110870China IEEE

Coal mine conveyor belt and other low-speed large torque system,the torque density and torque stability of the motor requirements are higher,permanent magnet/magnet reluctance hybrid rotor double stator synchronous motor(PM/MRHRDSSM)is just adapted to this requirement,however,the traditional close winding single inverter vector control system control PM/MRHRDSSM provides large torque ripple,high speed fluctuation and large total harmonic distortion(THD)of the current,difficult to be used in actual production and life,this paper proposes a large torque open winding-permanent magnet/magnet reluctance hybrid rotor double stator synchronous motor(OW-PM/MRHRDSSM)based on SVPWM dual inverter control strategy,and analysis of open winding double inverter structure,and its voltage vector mathematical model,using the existing two-level inverter as a basis,the bilateral inverter separately discussed its role and control method,as well as the decomposition method of synthetic voltage vector and the inverter device in the small sector on-time,the end of this paper through simulation to compare the traditional close winding single inverter vector control system control PM/MRHRDSSM and the large torque OW-PM/MRHRDSSM based on SVPWM dual inverter control strategy to prove the effectiveness of the proposed method in reducing torque ripple,speed fluctuation and THD of current during motor operation.

关键词： SVPWM Dual stator motor Hybrid rotor Open winding motor

A new depsidone from Usnea diffracta

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Chinese Chemical Letters 2009年第2期20卷 187-189页

作者： Huan Yang Qi Yuan Peng jin Yan Ping Shi Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China

A new depsidone, diffractione A （1）, as well as six known phenolic compounds （2-7） were isolated from Usnea diffracta. Their structures were elucidated by 1D and 2D NMR spectroscopy together with HRESIMS analysis.... 详细信息

关键词： Depsidone Usneaceae Usnea diffracta Lichen Diffractione A

Innovative strategies toward challenges in PV-powered electrochemical CO_(2)reduction

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Journal of Energy Chemistry 2021年第9期30卷 410-416页

作者： Siraj Sultan jin Hyun Kim Seung Hyeon Kim Youngkook Kwon Jae Sung Lee Department of Energy Engineering School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan 44919South Korea

The solar energy-driven electrochemical CO_(2)reduction to value-added fuels or chemicals is considered as an attractive path to store renewable energy in the form of chemical energy to close the carbon ***,CO_(2)reduction suffers from a number of challenges including slow reaction rates,low selectivity,and low energy conversion ***,innovative strategies have been developed to mitigate this *** the development of flow cell reactors with a gas diffusion electrode,ionic liquid electrolytes,and new electrocatalysts have dramatically improved the reaction rates and selectivity to desired *** this perspective,we highlight the key recent developments and challenges in PVpowered electrochemical CO_(2)reduction and propose effective strategies to improve the reaction kinetics,to minimize the electrical energy losses,and to tune the selectivity of the catalysts for desired products,and then suggest future direction of research and development.

关键词： Electrochemical CO_(2)reduction Photovoltaic cell Ionic liquid electrolytes Flow cell electrolyzers Gas diffusion electrode

Assay of Histamine in Single Mast Cells by Capillary Zone Electrophoresis with Electrochemical Detection

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Chinese Chemical Letters 2002年第10期13卷 982-984页

作者： Qian Feng WENG Fang Quan XIA Wen Rui jin School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100

Capillary zone electrophoresis was employed for the analysis of histamine in single rat peritoneal mast cells using an amperometric detector. In this method, individual mast cells and then 0.02 mol/L NaOH as a lysing solution are injected into the front end of the separation capillary. A cell injector was constructed for easy injection of single cells. Histamine in single mast cells has been identified and quantified.

关键词： Capillary electrophoresis electrochemical detection histamine mast cell.

Homopolymerization of N-pyrimidinyl acrylamide

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Chinese Chemical Letters 2007年第9期18卷 1141-1144页

作者： De Cheng Wan Hong Ting Pu Gen jin Yang Institute of Functional Polymers School of Materials Science&EngineeringTongji UniversityShanghai 200092China School of Pharmacy The Second Military Medical UniversityShanghai 200433China

Homopolymerization of N-pyrimidinyl acrylamide (NPA) was reported for the first time. The polymer (polyNPA) was soluble only in acidic media and fluoroalcohols, and only in fluoroalcohol was homogeneous polymerization of NPA feasible. 1H NMR analysis proved that a 1:1 H-bonding complex could be formed between NPA and α,α-bis(trifluoromethyl)phenyl propan-2-ol (BTMP). Cumyl dithiobenzoate mediated reversible addition-fragmentation chain transfer (RAFT) polymerization of NPA in BTMP was carried out. 1H NMR analyses proved that the molecular weight increased linearly with the monomer conversion. The polymer prepared in conventional solvents was atactic while in protic media the syndiotacticity was slightly enhanced.

关键词： N-pyrimidinyl acrylamide H-Bonding Fluoroalcohol Homopolymerization RAFT

A New Benzylisoquinoline Alkaloid from Sabia parviflora

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Chinese Chemical Letters 2002年第5期13卷 426-427页

作者： jin CHEN Bin CHEN Jun TIAN Feng E WU Laboratory of Natural Materia Medica Chengdu Institute of BiologyAcademia SinicaChengdu 610041

A new benzylisoquinoline alkaloid, 1, 2, 3, 4-tetrahydro-5-hydroxyl-8-methoxyl-2- methyl-4'-methoxyl-benzylisoquinoline, was isolated from the arial parts of Sabia parviflora. Its structure was established on the bas... 详细信息

关键词： Sabia parviflora benzylisoquinoline alkaloid 1, 2, 3, 4-tetrahydro-5-hydroxyl-8- methoxyl-2-methyl-4'-methoxyl-benzylisoquinoline.