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A New Triterpene from Cynanchum forrestii

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Chinese Chemical Letters 2006年第12期17卷 1569-1572页

作者： Yue liu jing QU shi Shan YU jing liu You Cai HU Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine Ministry of Education ＆ Institute of Materia Medica Peking Union Medical College and Chinese Academy of Medical Sciences Beijing 100050

A new triterpene, named cynanotriterpene A, with a ring-A-fission （3, 4-seco） and 13, 27-cyclours-3-oic acid methyl ester skeleton was isolated from the roots of Cynanchum forrestii Schlechter. The structure of the ... 详细信息

关键词： Cynanchumforrestii triterpene X-ray diffraction.

Effect of ZnO on the performance of Ag/SiO_2 catalyst for the vapor-phase synthesis of 3-methylindole

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Journal of Natural Gas Chemistry 2009年第4期18卷 445-448页

作者： Yang Hu Wenhui Lu Dongyan liu jing liu Lei shi Qi Sun Institute of Chemistry for Functionalized Materials Faculty of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116029 Liaoning China

The vapor-phase synthesis of 3-methylindole over Ag/SiO2 doped with ZnO was investigated. The catalysts were characterized by XRD, H2- TPR, NH3-TPD and TG techniques. The results indicated that ZnO promoter greatly enhanced the initial activity of the catalyst but disfavored its stability. H2-TPR and XRD results showed that the reduction peak of Ag2O shifted to higher temperature and the intensity of silver diffraction peaks was much weaker after the addition of ZnO promoter to Ag/SiO2. This indicated that there existed the interaction between Ag2O and SiO2-ZnO which promoted the silver particles dispersing on the support and inhibited the sintering of silver during the reaction. NH3-TPD and TG results revealed that the acid amounts of the catalyst and coking increased after adding ZnO to Ag/SiO2, which resulted in the deactivation of Ag/SiO2-ZnO catalyst rapidly.

关键词： ZnO Ag/SiO2 3-methylindole initial activity selectivity stability

Surface-neutralization engineered NiCo-LDH/phosphate hetero-sheets toward robust oxygen evolution reaction

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Green Energy & Environment 2024年第7期9卷 1151-1158页

作者： Shunfa Zhou Yuxuan liu jing Li Zhao liu Jiawei shi Liyuan Fan Weiwei Cai Sustainable Energy Laboratory Faculty of Materials Science and Chemistry China University of Geosciences College of Science and Engineering James Cook University

Developing highly active oxygen evolution reaction（OER） electrocatalysts with robust durability is essential in producing high-purity hydrogen through water electrolysis. Layered double hydroxide（LDH） based catalysts have demonstrated efficient catalytic performance toward the relatively sluggish OER. By considering the promotion effect of phosphate（Pi） on proton transfer, herein, a facile phosphate acid（PA）surface-neutralization strategy is developed to in-situ construct NiCo-LDH/NiCoPi hetero-sheets toward OER catalysis. OER activity of NiCoLDH is significantly boosted due to the proton promotion effect and the electronic modulation effect of NiCoPi. As a result, the facilely prepared NiCo-LDH/NiCoPi catalyst displays superior OER catalytic activity with a low overpotential of 300 mV to deliver 100 mA cm-2OER and a Tafel slope of 73 mV dec-1. Furthermore, no visible activity decay is detected after a 200-h continuous OER operation. The present work,therefore, provides a promising strategy to exploit robust OER electrocatalysts for commercial water electrolysers.

关键词： Oxygen evolution reaction Phosphate Layered double hydroxide Hetero-sheets Stability

An uncertainty investigation for liner impedance eduction methods

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Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao shi Xiaodong jing School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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Nuclear Science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-Jie Sun jing-Yi shi Yi-Fei liu Shang-Ming Chen liu-liu Li State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path

The microwave absorption of ceramic-cup microwave ion source

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Nuclear Science and Techniques 2000年第3期11卷 155-161页

作者： liu Lin-Mao, jing shi-Wei, LI Wen-Sheng, GU Li (Physics Department, foe Northeast Normal University, Changchun 130024) 东北师范大学吉林长春 130024

An experiment system of ceramic-cup microwave ion source has been built here. Its microwave absorption efficiency as a function of the magnetic field and the pressure is presented. When the microwave incident power is 300-500W the microwave absorption efficiencies are more than 90% if the system is optimized and the magnetic field at the microwave window is 0.095T.

关键词：微波离子源中子管陶瓷材料微波吸收效率电子回旋加速器

Isolation and Complete Nucleotide Sequence of the Measles Virus IMB-1 Strain in China

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Virologica Sinica 2010年第6期25卷 381-389页

作者： Shao-hui MA Li-chun WANG Jian-sheng liu Hai-jing shi Long-ding liu Qi-han LI Institute of Medical Biology Chinese Academy of Medical Sciences and Peking Union Medical College Kunming 650118 China

The complete nucleotide sequence of the measles virus strain IMB-1,which was isolated in China,was *** in other measles viruses,its genome is 15,894 nucleotides in length and encodes six *** full-length nucleotide sequence of the IMB-1 isolate differed from vaccine strains (including wild-type Edmonston strain) by 4%-5% at the nucleotide sequence *** isolate has amino acid variations over the full genome,including in the hemagglutinin and fusion *** report is the first to describe the full-length genome of a genotype H1 strain and provide an overview of the diversity of genetic characteristics of a circulating measles virus.

关键词： Complete nucleotide sequence Genotype H1 Measles virus (MV)

Eco-Environmental Vulnerability Evaluation in the Yellow River Basin,China

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Pedosphere 2008年第2期18卷 171-182页

作者： WANG Si-Yuan liu jing-shi YANG Cun-Jian Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 （China） Institute of Electronics Chinese Academy of Sciences Beijing 100080 （China） Centre of RS and GIS Applications Sichuan Normal University Chengdu 610066 （China）

Using remote sensing(RS)data and geographical information system(GIS),eco-environmental vulnerability and its changes were analyzed for the Yellow River Basin,*** objective of this study was to improve our understanding of eco-environmental changes so that a strategy of sustainable land use could be *** environmental numerical model was developed using spatial principal component analysis(SPCA)*** model contains twelve factors that include variables of land use,soil erosion,topography,climate,and *** this model,synthetic eco- environmental vulnerability index(SEVI)was computed for 1990 and 2000 for the Yellow River *** SEVI was classified into six levels,potential,slight,light,medium,heavy,and very heavy,following the natural breaks classification. The eco-environmental vulnerability distribution and its changes over the ten years from 1990 to 2000 were analyzed and the driving factors of eco-environmental changes were *** results show that the eco-environmental vulnerability in the study area was at medium level,and the eco-environmental quality had been gradually improved on the ***,the eco-environmental quality had become worse over the ten years in some *** the study area,population growth,vegetation degradation,and governmental policies for eco-environmental protection were found to be the major factors that caused the eco-environmental changes over the ten years.

关键词： eco-environmental vulnerability geographic information system (GIS) remote sensing (RS) spatial principal component analysis Yellow River Basin

Carbon cathode with heteroatom doping and ultrahigh surface area enabling enhanced capacitive behavior for potassium-ion hybrid capacitors

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Rare Metals 2024年第5期43卷 2136-2149页

作者： Yan Xiong Ya-Fei Zhang Chun-liu Zhu Lei Yang Huan-Yu Liang jing shi jing-Wei Chen Wei-QianTian Shuai liu Zhi Li jing-Yi Wu Huan-Lei Wang School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 2V4Canada

Potassium-ion hybrid capacitors(PIHCs)are widely regarded as highly promising energy storage devices,due to their exceptional energy density,impressive power density,and abundant potassium ***,restricted by the inherent capacitive storage mechanism,the carbon cathodes possess a much lower specific capacity than battery-type ***,designing high-performance carbon cathodes is extremely urgent for the development of ***,N,O codoped porous carbon(NOPC)was fabricated through the NaCl hard template method and combined KOH/melamine chemical activation technique,displaying the characteristics of abundant N/O content(4.7 at%/16.9 at%),ultrahigh specific surface area(3092 m^(2)g^(-1))and hierarchical pore *** designed NOPC cathode delivers a high specific capacity(164.4 mAh.g^(-1)at 0.05 A.g^(-1))and superior cyclability(95.1%retention ratio at 2 A·g^(-1)over 2500 cycles).Notably,the adjustable ratio of micropores to mesopores facilitates the achievement of the optimal bal-ance between capacity and rate ***,the pseudocapacitance can be further augmented through the incorporation of N/O functional *** expected,the graphite//NOPC based PIHC possesses a high energy density of 113 Wh·kg-at 747 W·kg^(-1)and excellent capacity retention of 84.4% fter 400 cycles at 1.0 A·g^(-1).This work introduces a novel strategy for designing carbon cathodes that enhances the electrochemical performance of PIHCs.

关键词： Template method N/O co-doping High specific surface area Carbon cathode Potassium-ion capacitors