检索结果-南通市图书馆

Computer Modeling in Engineering & Sciences 2019年第11期121卷 425-444页

作者： Tianyi Li Xin gu qing Zhang Dong Lei Department of Engineering Mechanics Hohai UniversityNanjingChina

Digital image correlation(DIC)measurement technique and peridynamics(PD)method have been applied in specific fields extensively owing to their respective advantages in obtaining full-field deformation and local failure of loaded materials and *** study provides a simple way to couple DIC measurements with PD simulations,which can circumvent the difficulties of DIC in dealing with discontinuous *** the failure analysis of a compact tension specimen of aluminum alloy and a static three-point bending concrete beam as examples,the DIC experimental system firstly measures the full-field displacements,and then the PD simulation is applied on potential damage regions determined according to the correlation coefficients,to track the micro-crack evolution and macro-crack *** results,the coupled DIC and PD approach can effectively measure the full-field displacement and the localized damage accumulation and crack propagation.

关键词： Digital image correlation peridynamics discontinuity damage

One-dimensional(1D) micro/nanostructures of organic semiconductors for field-effect transistors

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Science China Chemistry 2015年第6期58卷 937-946页

作者： Yu-qing Zheng Jie-Yu Wang jian Pei Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry and Molecular Engineering Peking University

Organic semiconductors have gradually become the super stars on the stage of optoelectronic materials, due to their low cost, flexibility and solution processability. Numerous organic semiconductors, including small molecules and conjugated polymers, have been designed and synthesized to explore the potential of organic materials in optoelectronic industry. One-dimensional micro/nanostructures of organic semiconductors generally have more ordered packing structure with fewer defects compared with thin films, and are thus thought to show intrinsic carrier mobility of organic materials. Moreover, the packing structure in micro/nanostructures is clear and relatively easy to analyze, which makes these micro/nanostructures a good platform to study structure-property relationship. Therefore, design of suitable organic molecules to form micro-/nanostructures and methods to obtain ideal micro/nanostructures for functional devices will be fully discussed in this mini review. Finally, the perspective and opportunity of 1D micro/nanostructured organic materials based OFETs in the near future are also addressed.

关键词： organic semiconductors organic field-effect transistors one-dimensional micro/nanostructures self-assembly

Radicals as Chiral Catalysts for Asymmetric Radical Cyclization Reactions

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Chinese Journal of Chemistry 2024年第19期42卷 2412-2416页

作者： Quan-qing Zhao Min gu Jia-Rong Chen jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening College of PharmacyJliangsu Ocean UniversityLianyungangJiangsu 222005China Engineering Research Center of Photoenergy Uitilization for Pollution Control and Carbon Reduction College of ChemistryCentral China Normal UniversityWuhanHubei 430079China

Due to the innate highly reactive properties and short life-time,organic free radicals can often serve as promoters or intermediates to engage in various radical transformations,which are often otherwise difficult to access by ionic pathway-based *** the evolvement of radical chemistry,chiral radical catalyzed-transformations have recently emerged as an attractive and robust platform for synthesis of chiral molecules of ***,we highlight several creative and strategic advances in chiral radical catalyst design,cyclization reaction achievements,and future challenges.

关键词： Chiral radical catalysis Radical cyclization Thiyl radical Boryl radical Asymmetric synthesis

Imaging the interphase of carbon fiber composites using transmission electron microscopy:Preparations by focused ion beam, ion beam etching, and ultramicrotomy

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Chinese Journal of Aeronautics 2015年第5期28卷 1529-1538页

作者： Wu qing Li Min gu Yizhuo Wang Shaokai Zhang Zuoguang Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and Engineering Beihang University

Three sample preparation techniques, focused ion beam （FIB）, ion beam （IB） etching, and ultramicrotomy （UM） were used in comparison to analyze the interphase of carbon fiber ＇epoxy composites using transmission electron microscopy. An intact interphase with a relatively uniform thickness was obtained by FIB. and detailed chemical analysis of the interphase was investigated by electron energy loss spectroscopy. It shows that the interphase region is 200 mn wide with an increasing oxygen-to-carbon ratio from 10% to 19% and an almost constant nitrogen-to-carbon ratio of about 3%. However, gallium implantation of FIB tends to hinder fine structure analysis of the interphase. For IB etching, the interphase region is observed with transition morphology frona amorphous resin to nano-crystalline carbon fiber, but the uneven sample thickness brings difficulty for quantitative chemical analysis. Moreover, UM tends to cause damage and/or deformation on the interphase. These results are meaningful for in-depth understanding on the interphase characteristic of carbon fiber composites.

关键词： Carbon fiber compositeChemical analysis Focused ion beams lnterphase Ion beam etching Microstructure Ultramicrotomy

THREE DIMENSIONAL NUMERICAL SIMULATION OF EXCAVATION AND BACKFILLING IN MINING ENGINEERING

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中国有色金属学会会刊：英文版 1999年第2期9卷 213-217页

作者： gu, Desheng Deng, jian Li, Xibing Zhang, Jiasheng Central South Univ of Technology Changsha China

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｔｈｉｒｔｙｙｅａｒｓ，ｗｉｔｈｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｃｏｍｐｕｔｅｒｔｅｃｈｎｉｑｕｅ，ｉｔｂｅｃｏｍｅｓｐｏｓｉｂｌｅｔｏｓｉｍｕｌａｔｅｓｕｃｈｃｏｍｐｌｉ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｔｈｉｒｔｙｙｅａｒｓ，ｗｉｔｈｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｃｏｍｐｕｔｅｒｔｅｃｈｎｉｑｕｅ，ｉｔｂｅｃｏｍｅｓｐｏｓｉｂｌｅｔｏｓｉｍｕｌａｔｅｓｕｃｈｃｏｍｐｌｉｃａｔｅｄｐｒｏｃｅｓｅｓａｓｍｉ...

关键词： mining engineeringexcavationbackfillingnumerical simulation

Selective reduction of carbon dioxide into amorphous carbon over activated natural magnetite

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 231-237页

作者： Zhong-qing Liu jian Zheng Yi Wang Xu Liu School of Chemical Engineering Sichuan UniversityChengdu 610065China

Natural magnetite formed by the isomorphism substitutions of transition metals,including Fe,Ti,Co,etc.,was activated by mechanical grinding followed by H2 *** temperature-programmed reduction of hydrogen(H2-TPR)and temperature-programmed surface reaction of carbon dioxide(CO2-TPSR)were carried out to investigate the processes of oxygen loss and CO2 *** samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM),and energy-dispersive X-ray spectroscopy(EDS).The results showed that the stability of spinel phases and oxygen-deficient degree significantly increased after natural magnetite was mechanically milled and reduced in H2 ***,the activity and selectivity of CO2 reduction into carbon were *** deposited carbon on the activated natural magnetite was confirmed as *** amount of carbon after CO2 reduction at 300°C for 90 min over the activated natural magnetite was 2.87wt%higher than that over the natural magnetite.

关键词： carbon dioxide reduction natural magnetite isomorphism substitutions grind activation oxygen-deficient degree amorphous carbon

Four new orientation relationships of Mg_(17)Al_(12) phase with magnesium matrix in Mg-8Al-0.5Zn alloys

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Journal of Magnesium and Alloys 2023年第12期11卷 4689-4695页

作者： Feiya Liu Renlong Xin Xin Wen Xinfu gu qing Liu Joint International Laboratory for Light Alloys(MOE) College of Materials Science and EngineeringChongqing UniversitySha Zheng Jie 174Sha Ping Ba District Chongqing 400044China National Engineering Research Center for Mg Alloys Chongqing UniversityChongqingChina School of Materials Science and Engineering University of Science and Technology BeijingBeijingChina Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjingChina

Although the non-basal precipitates, those not parallel to the basal plane, are more effective to block basal slip in Mg-Al alloys, the crystallographic orientation relationship(OR) between these precipitates and the α-Mg matrix has not been well established. In this work, the crystallography of the non-basal Mg_(17)Al_(12) precipitates in AZ80 alloy was systematically investigated by transmission electron microscopy(TEM). By tilting to a suitable electron beam direction, different kinds of non-basal precipitates were recognized in TEM, and the following four new ORs between the non-basal Mg_(17)Al_(12) precipitates and the matrix were revealed: ■, and ■.Furthermore, these ORs and their habit planes were explained using the edge-to-edge matching model. The findings in this work can provide some guidelines for designing the microstructure of Mg-Al alloys to enhance their precipitation hardening potential.

关键词： Mg alloys Precipitate Orientation relationship Crystallography Edge-to-edge matching model

Diverse Roles of Immune Cells in Transplant Rejection and Immune Tolerance

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Engineering 2022年第3期8卷 44-56页

作者： Xiaojie Gan jian gu Zheng Ju Ling Lu Hepatobiliary Center The First Affiliated Hospital of Nanjing Medical University&Research Unit of Liver Transplantation and Transplant ImmunologyChinese Academy of Medical SciencesNanjing 210029China

Organ transplant rejection(OTR)is a complex immune reaction involving multiple cells,and it determines graft survival and patient *** present,most transplant recipients are administered a combination of immunosuppressive and biological agents to protect them from ***,immunosuppressive agents negatively impact the immune system of the patients,causing them to suffer from serious complications,such as chronic infection and malignant ***,a thorough understanding of the mechanisms involved in immune tolerance and immune rejection with regard to organ transplant(OT)is essential for developing better treatment options and improving patient *** article reviews the role of immune cells in OTR and organ transplant tolerance(OTT),including the novel cell therapies that are currently under clinical trials for transplant recipients.

关键词： Immune cells Innate immune cells Adaptive immune cells Organ transplant Immune tolerance

The holographic fermions dual to massive gravity

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Science China(Physics,Mechanics & Astronomy) 2016年第10期59卷 49-57页

作者： Li-qing Fang[[ Xiao-Mei Kuang jian-Pin Wu School of Physics and Electronic Information Shangrao Normal UniversityShangrao 334000China Department of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of High Temperature Superconductors Shanghai 200444China Instituto de Fisica Pontificia Universidad Catolica de ValparaisoCasilla 4059ValparaisoChile Institute of Gravitation and Cosmology Department of PhysicsSchool of Mathematics and PhysicsBohai UniversityJinzhou 121013China

We investigate the properties of the spectral function of the fermionic operator in the field theory which is dual to a 4-dimensional massive gravity. We first study the Fermi surface and the dispersion relation in the dual boundary theory. We find that as the massive parameters is decreased, the Fermi momentum becomes lower and the low energy excitation near Fermi surface behaves more like non-Fermi liquid. Then, we introduce a dipole coupling in the bulk theory and explore the emergence of a gap in the fermionic spectral function. It is found that larger critical dipole coupling is needed to open the gap than that in Einstein gravity. Accordingly,in the field theory dual to massive gravity, it requires stronger negative dipole coupling to generate the marginal Fermi liquid.

关键词： holography duality AdS/CFT correspondence holographic fermions

Compliant Control of Lower Limb Rehabilitation Exoskeleton Robot Based on Flexible Transmission

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Journal of Bionic Engineering 2023年第3期20卷 1021-1035页

作者： Keping Liu Li Li Wanting Li jian gu Zhongbo Sun Department of Control Science and Engineering Changchun University of TechnologyChangchun130012China Department of Electrical and Information Engineering Jilin Engineering Normal UniversityChangchun130052China

To ensure the safety, comfort, and effectiveness of lower limb rehabilitation exoskeleton robots in the rehabilitation training process, compliance is a prerequisite for human–machine interaction safety. First, under the premise of considering the mechanical structure of the lower limb rehabilitation exoskeleton robot (LLRER), when conducting the dynamic transmission of the exoskeleton knee joint, the soft axis is added to ensure that the rotation motion and torque are flexibly transmitted to any position to achieve flexible force transmission. Second, to realize the active compliance control of LLRER, the sliding mode impedance closed-loop controller is developed based on the kinematics and dynamics model of LLRER, and the stability of the designed control system is verified by Lyapunov method. Then the experiment is designed to track the collected bicycle rehabilitation motion data stably, and the algorithm and dynamic model are verified to satisfy the experimental requirements. Finally, aiming at the transmission efficiency and response performance of the soft shaft in the torque transmission process of the knee joint, the soft shaft transmission performance test is carried out to test the soft shaft transmission performance and realize the compliance of the LLRER, so as to ensure that the rehabilitation training can be carried out in a safe and comfortable interactive environment. Through the design of rehabilitation exercise training, it is verified that the LLRER of flexible transmission under sliding mode impedance control has good adaptability in the actual environment, and can achieve accurate and flexible control. During the experiment, the effectiveness of monitoring rehabilitation training is brought through the respiratory belt.

关键词： Lower limb rehabilitation exoskeleton Flexible control Impedance control Stability