检索结果-南通市图书馆

Effect of Al and Zn additives on grain size of Mg-3Ni-2MnO_(2) alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2009年第S2期19卷 355-358页

作者： FANG wa SUN Hong-fei FANG Wen-bin waNG Bin School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

The effect of Al and Zn additives on the grain size of Mg-3Ni-2MnO_(2) alloy was *** nanostructured Mg-3Ni-2MnO_(2) and Mg-3Ni-2MnO_(2)-3Al-Zn were made by ball milling process under hydrogen *** XRD results and TEM analysis reveal that Al and Zn additives almost have no effect on the grain size of Mg-3Ni-2MnO_(2) *** present study provides us a feasibility of producing nano-structured magnesium alloys,based on hydrogenation,disproportionation,desorption and recombination(HDDR),by adding beneficial elements to hydrogen storage materials.

关键词： nanocrystalline magnesium alloy hydrogenation-disproportionation-desorption-recombination(HDDR) ball milling

A Computational Study of Asymmetric Hydrogenation of 2-Phenyl Acrylic Acids Catalyzed by a Rh(l) Catalyst with Ferrocenyl Chiral Bisphosphorus Ligand: The Role of Ion-Pair Interaction

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2021年第6期39卷 1616-1624页

作者： Xiangru Fan Lini Zheng Yuhong Yang Xiu-Qin Dong Xumu Zhang Lung-wa Chung Deportment of Chemistry Guangdong Provincial Key Laboratory of Catalysis and Shenzhen Grubbs InstituteSouthern University of Science and TechnologyShenzhenGuangdong 518055China Key Laboratory of Biomedical Polymers Engineering Research Center of Organosilicon Compounds&MaterialsMinistry of EducationCollege of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei 430072China

Asymmetric hydrogenation reaction is one of the most efficient synthetic methods to form useful chiral compounds for synthetic chemistry,medicinal chemistry and material ***,the enantioselectivity of many hydrogenation reactions is controlled by steric hindrance between the chiral ligand and ***,Zhang group developed a highly asymmetric hydrogenation of 2-aryl and 2-alkyl acrylic acids catalyzed by a Rh(l)catalyst with a chiral Wudaphos *** excellent enantioselectivity of this asymmetric reaction was proposed to be controlled by ion-pair interaction between the substrate and chiral *** this study,a systematic density functional theory study has been carried out to investigate the reaction mechanism and origin of the *** computational results suggest that this reaction follows the classic mechanism involving oxidative addition of H_(2),migratory insertion and reductive *** from the C=C coordination to the metal in the common oxidative addition step,our study found that the chelation of the carboxyl group of the substrate to the cationic Rh(l)metal is more favorable in this oxidative addition *** high enantioselectivity is proposed to be dictated by a better catalyst/substrate geometric complementarity in the major pathway to have less distortion of the catalyst for a strong ion-pair interaction.

关键词： Hydrogenation Enantioselectivity Reaction mechanism Density functional theory Ion-pair interaction

EXPERIMENTAL STUDY ON THE MECHANISM OF THE RICHTMYERMESHKOV INSTABILITY AT A gaS-LIQUID INTERFACE

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2009年第3期21卷 423-428页

作者： SHI Hong-hui ZHANG ga DU Kai JIA Hui-xia College of Mechanical Engineering and Automation Zhejiang University of Science and Technology Hangzhou 310018 China

The mechanism of the Richtmyer-Meshkov instability was experimentally studied in a vertical rectangular shock tube. The velocity of the interface driven by the shock wave was measured by a self-designed measurement system, which consists of semiconductor lasers, signal amplification circuits, digital oscilloscope and computer. Tests were carded out at several shock wave Mach numbers. In addition, the movement of the interface and the variation of the mixed zone width with time were recorded by high-speed photography. The experimental results show that the interface velocity increases with the increase of the Mach number, and the distance of the interface＇s movement and the width of the mixed zone vary with time in a linear relationship.

关键词： Richtmyer-Meshkov instability shock wave shock tube laser interface

Production of composites with high relative permittivity using the spouted bed technique

在线全文

学校读者我要写书评

暂无评论

Particuology 2019年第1期17卷 184-189页

作者： E. Eichner P.-K. Fischer S. Heinrich ga Schneider Institute of Solids Process Engineering and Particle Technology Denickestr1521073 HamburgGermany Institute of Advanced Ceramics Hamburg University of TechnologyDenickestr1521073 HamburgGermany

This contribution presents a new application of the spouted bed technique. The developed production process involves coating fine copper particles with a polymer in a spouted bed plant and then hot pressing the produced granules to form a compact consisting of a copper–polymer composite with a high filling degree. The fabricated composites possess high relative permittivity, which is advantageous for the production of effective capacitors. With increasing filling degree of copper, the relative permittivity of the composites increased, with a maximum relative permittivity of 214 obtained for the composite containing 78.1 vol% copper. Such a high filling degree can be achieved with conductive particles without obtaining a conductive composite by using the spouted bed technology in the production process. The high relative permittivity results from the high filling degree of particles isolated by a polymer coating.

关键词： Spouted bed High relative permittivity Fine particles Coating Metal-polymer composite

Design and research of magnetic field sensor based on grapefruit optical fiber filled with magnetic fluid

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2022年第5期18卷 269-275页

作者： waNG Mengye JIN wa LIU Xuejing SUN Wenjie ZHANG Chenhui BI Weihong College of Information Science and Engineering Yanshan UniversityQinhuangdao066000China The Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province Qinhuangdao066000China College of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China

A novel magnetic field sensor was proposed based on the grapefruit optical fiber with the magnetic fluid injected into the six air *** sensor utilizes the Mach-Zehnder interference(MZI).The light is transmitted through the single-mode fiber to the fusion splice point and is divided into two *** the light passes through the cladding air hole with magnetic fluid,it interferes with the core light,and the change of the interference light is related with the change of the magnetic *** sensor cavity length is 6 *** can be obtained from the experimental results that the magnetic field sensitivity reaches up to 2.243 nm/Oe with the range from 0 to 2.28 *** sensor has the advantages of easy fabrication,easy installation and low *** findings provide new ideas for the study of ocean wind electromagnetic fields.

关键词： fiber optical magnetic

SYMPLECTIC SCHEMES FOR QUASILINEAR waVE EQUATIONS OF KLEIN-GORDON AND SINE-GORDON TYPE

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第5期19卷 475-488页

作者： Xiao-wu Lu (Department of Mathematics and Computer Science, Emory University, Atlanta, ga 30322, USA) Emory University 美国 30322

Presents a class of finite difference methods of first and second order accuracy for the computation of solutions to the quasilinear wave equations. Overview of general symplectic schemes and generating functional; Nu... 详细信息

关键词： Symplectic integration Sine-Gordon equations Finite difference method.

Recent progress on lanthanide complexes/clay minerals hybrid luminescent materials

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2022年第9期40卷 1360-1370,I0001页

作者： ga Zhang Lefu Mei Junjie Ding Ke Su Qingfeng Guo Guocheng Lv Libing Liao Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid wastes National Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of GeosciencesBeijing 100083China School of Gemmology China University of GeosciencesBeijing 100083China

The unique luminescent performance of lanthanide complexes/clay minerals hybrid materials has been fascinating many researchers for recent *** not only retains the excellent luminescent characteristics of lanthanide complexes but also improves the poor stability of the *** this article,we introduce the luminescence mechanism of lanthanide complexes and point out the necessity of their combination with clay *** the analysis of the structure and interlayer environment differences of 1:1-type and 2:1-type clay minerals,the intercalation methods(covalent grafting and ion exchange)appropriate for different clay minerals are summarized with *** on the luminescence characteristics of the hybrid materials,the applications of these materials as luminescent probes in recognition of specific metal cations and molecules,detection of pH value,and temperature are ***,the current problems in the preparation of lanthanide complexes/clay minerals hybrid luminescent materials and shortcomings that need improvement in their performance are analyzed,and the application prospect is forecast.

关键词： Luminescence Hybrid materials Lanthanide complexes Clay minerals Luminescent probes Rare earths

Dynamic Response of Sea-Crossing Rail-cum-Road Cable-Stayed Bridge Influenced by Random Wind–wave–Undercurrent Coupling

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2023年第1期37卷 85-100页

作者： BIAN Chen-jie DU Li-ming waNG ga-ping LI Xin LI Wei-ran School of Civil Engineering Dalian Jiaotong UniversityDalian 116028China School of Locomotive and Rolling stock Engineering Dalian Jiaotong UniversityDalian 116028China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

Sea-crossing bridges are affected by random wind–wave–undercurrent coupling loads, due to the complex marine environment. The dynamic response of long-span Rail-cum-Road cable-stayed bridges is particularly severe under their influence, potentially leading to safety problems. In this paper, a fluid–structure separation solution method is implemented using Ansys–Midas co-simulation, in order to solve the above issues effectively while using less computational resources. The feasibility of the method is verified by comparing the tower top displacement response with relevant experimental data. From time and frequency domain perspectives, the displacement and acceleration responses of the sea-crossing Rail-cum-Road cable-stayed bridge influenced by wave-only, wind–wave, and wind–wave–undercurrent coupling are comparatively studied. The results indicate that the displacement and acceleration of the front bearing platform top are more significant than those of the rear bearing platform. The dominant frequency under wind–wave–undercurrent coupling is close to the natural vibration frequencies of several bridge modes,such that wind–wave–undercurrent coupling is more likely to cause a resonance effect in the bridge. Compared with the wave-only and wind–wave coupling, wind–wave–undercurrent coupling can excite bridges to produce larger displacement and acceleration responses: at the middle of the main girder span, compared with the wave-only case, the maximum displacement in the transverse bridge direction increases by 23.58% and 46.95% in the wind–wave and wind–wave–undercurrent coupling cases, respectively;at the tower top, the variation in the amplitude of the displacement and acceleration responses of wind–wave and wind–wave–undercurrent coupling are larger than those in the wave-only case, where the acceleration change amplitude of the tower top is from-0.93 to 0.86 m/s^(2) in the waveonly case, from-2.2 to 2.1 m/s^(2) under wind–wave coupling effect, and from-2.6 to 2.6

关键词： random wind wave undercurrent coupling effect Rail-cum-Road cable-stayed bridge dynamic response

Combating Drug Resistance in Colorectal Cancer Using Herbal Medicines

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2021年第7期27卷 551-560页

作者： Lee ga-Young Lee Jin-Seok Son Chang-Gue Lee Nam-Hun Department of Clinical Oncology Cheonan Korean Medicine Hospital of Daejeon UniversityCheonan31099Republic of Korea Liver&Immunology Research Center Dunsan Korean Medicine Hospital of Daejeon UniversityDaejeon35235Republic of Korea Department of Internal Medicine Graduated School of Korean MedicineUniversity of DaejeonDaejeon34520Republic of Korea

Colorectal cancer(CRC)is one of the most prevalent and lethal cancer types around the *** of the CRC patients are treated with chemotherapeutic drugs alone or ***,up to 90%of metastatic cancer patients experience the failure of treatment mostly because of the acquired drug resistance,which can be led to multidrug resistance(MDR).In this study,we reviewed the recent literature which studied potential CRC MDR reversal agents among herbal medicines(HMs).Among abundant HMs,6 single herbs,Andrographis paniculata,Salvia miltiorrhiza,Hedyotis diffusa,Sophora flavescens,Curcuma longa,Bufo gargarizans,and 2 formulae,Pien Tze Huang and Zhi Zhen Fang,were found to overcome CRC MDR by two or more different mechanisms,which could be a promising candidate in the development of new drugs for adjuvant CRC chemotherapy.

关键词： colorectal cancer drug resistance herbal medicine