检索结果-南通市图书馆

Leakage in Mold Slit during Inverse Solidification

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2001年第2期8卷 101-104页

作者： zhang, jm Wang, XH Wang, WJ Univ Sci & Technol Beijing Met Sch Beijing 100083 Peoples R China

The liquid steel will be leaked from the slit between the bottom of solidification mold and mother sheet during inversion casting process. By substitution of the actual liquid steel, the Ph-Sn alloy and the numerical simulation can be used to study the fluid flow in the inversion solidification mold, the mother sheet critical speed is determined for preventing the leakage from the slit of bottom. When the mother sheet speed is more than 0.06 m/s, Pb-Sn liquid alloy will not leak from the slit of the mold. Otherwise, the Ph-Sn liquid alloy can leak from the slit of the mold.

关键词： leakage slit inverse solidification mold

Energy transfer mechanism of PBS-thylakoid complexes——By deconvolution spectra and steady-state spectra (77 K) techniques

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第20期42卷 1689-1693页

作者： zhang, jm Zhao, JQ Jiang, LJ Acad Sinica Inst Photog Chem Beijing 100101 Peoples R China

Up to now, the energy transfer study has been focused on the composite of isolated PBSs, PCand APC, as well as isolated PS Ⅱ and PS Ⅰparticles with time-resolved fluorescence tech-niques. Although these studies give more important information about the energy transferamong them, they cannot explain why the energy transfer from PBS to reaction centers

关键词： PBS-thylakoid complex steady-state spectra deconvolution.

Isolation and characterization of rod-core complex from the phycobilisome of Anabaena variabilis

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第13期42卷 1103-1107页

作者： zhang, jm Zhao, JQ Xie, J zhang, JP Jiang, LJ Institute of Photographic Chemistry Chinese Academy of Sciences Beijing 100101 China

THE phycobilisomes (PBSs) of A. variabilis, like most other cyanobacteria and red alage,are hemi-discoidal. They contain various phycobiliproteins such as phycoerythrocyanin(PEC), C-phycocyanin (C-PC) and allophycocyanin (APC), and the energy transfer flowscan be examplified by the following scheme: PEC→C-PC→APC. Although the high resolu-tion crystal structures of PEC, C-PC and APC have been determined by X-ray method,

关键词： Anabaena variabilis rod-core complex model energy transfer.

Preparation of Chiral Quaternary Ammonium Salts and Initial Study of Asymmetric Phase Transfer Catalytic Alkylation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第12期8卷 0-0页

作者： Lou, RL Mi, AQ Zhou, ZY zhang, jm Jiang, YZ Acad Sinica Chengdu Inst Organ Chem Chengdu 610041 Peoples R China

A number of chiral quaternary ammonium salts were synthesized from (1 R,2S)-(-)-1,2-diphenyl-2-aminoethanol and applied to the enantioselective alkylation

关键词： Am PTC Preparation of Chiral Quaternary Ammonium Salts and Initial Study of Asymmetric Phase Transfer Catalytic Alkylation

Energy transfer mechanism of PBS-thylakoid complexes——By time-resolved fluorescence spectra technique

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第20期42卷 1699-1703页

作者： zhang, jm Zhao, JQ Jiang, LJ Zheng, XG Zhao, FL Wang, HZ Acad Sinica Inst Photog Chem Beijing 100101 Peoples R China

IN a previous paper, we have studied the energy transfer mechanism among the PBS-thy-lakoid complex in detail by using steady-state spectra and deconvolution techniques. The ex-perimental results indicated that the energy transfer from PBS to two reaction centers of PS Ⅰand PS Ⅱ were parallel, and confirmed the model which was suggested by Mullineaxu.

关键词： PBS-thylakoid complex time-resolved fluorescence spectra energy transfer.

Geometric Error Identification of Gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第2期37卷 150-162页

作者： Jun Zha Huijie zhang School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Jiaotong University Suzhou Academy Suzhou 215123China

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial *** propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine *** method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement *** consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic *** four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization *** experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser *** a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed *** research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

关键词： Multi-point positioning Multi-station synchronization CNC machine tool Geometric error Error separation

Geometric error measuring,modeling,and compensation for CNC machine tools:A review

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

Chinese Journal of Aeronautics 2024年第2期37卷 163-198页

作者： Zhao zhang Feng JIANG Ming LUO Baohai WU Dinghua zhang Kai TANG Engineering Research Center of Advanced Manufacturing Technology for Aero Engine(Northwestern Polytechnical University) Ministry of EducationXi’an 710072China Key Laboratory of High Performance Manufacturing for Aero Engine(Northwestern Polytechnical University) Ministry of Industry and Information TechnologyXi’an 710072China Department of Mechanical and Aerospace Engineering Hong Kong University of Science and TechnologyHong KongChina

Geometric error,mainly due to imperfect geometry and dimensions of machine components,is one of the major error sources of machine *** that geometric error has significant effects on the machining quality of manufactured parts,it has been a popular topic for academic and industrial research for many years.A great deal of research work has been carried out since the 1970s for solving the problem and improving the machining *** have studied how to measure,detect,model,identify,reduce,and compensate the geometric *** paper presents a thorough review of the latest research activities and gives an overview of the state of the art in understanding changes in machine tool performance due to geometric *** advances in measuring the geometrical errors of machine tools are summarized,and different kinds of error identification methods of translational axes and rotation axes are illustrated ***,volumetric geometric error modeling,tracing,and compensation techniques for five-axis machine tools are emphatically ***,research challenges in order to improve the volumetric accuracy of machine tools are also highlighted.

关键词： Error compensation Error identification Error measurement Error modeling Geometric error Machine tools

“Capture-activation-recapture” mechanism-guided design of double-atom catalysts for electrocatalytic nitrogen reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第9期96卷 437-447页

作者： Cheng He Shiqi Yan Wenxue zhang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science1nd EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina School of Materials Science1nd Engineering Chang’an UniversityXi’an 710064ShaanxiChina

Compared with the traditional industrial nitrogen fixation, electrocatalytic methods, especially those utilizing double-atom catalysts containing nonmetals, can give good consideration to the economy and environmental protection. However, the existing “acceptance-donation” mechanism is only applicable to bimetallic catalysts and nonmetallic double-atom catalysts containing boron atoms. Herein, a novel “capture-activation-recapture” mechanism for metal-nonmetal double-atom catalyst is proposed to solve the problem by adjusting the coordination environments of nonmetallic atoms and utilizing the activation effect of metal atoms on nitrogen. Based on this mechanism, the nitrogen reduction reaction (NRR) activity of 48 structures is calculated by density functional theory calculation, and four candidates are selected as outstanding electrocatalytic nitrogen reduction catalysts: Si-Fe@NG (U_(L) = –0.14 V), Si-Co@NG (U_(L)= –0.15 V), Si-Mo@BP1 (U_(L) = 0 V), and Si-Re@BP1 (U_(L) = –0.02 V). The analyses of electronic properties further confirm “capture-activation-recapture” mechanism and suggest that the difference in valence electron distribution between metal and Si atoms triggers the activation of N≡N bonds. In addition, a machine learning approach is utilized to generate an expression and an intrinsic descriptor that considers the coordination environment to predict the limiting potential. This study offers profound insight into the synergistic mechanism of TM and Si for NRR and guidance in the design of novel double-atom nitrogen fixation catalysts.

关键词： "Capture-activation-recapture"mechanism Double-atom catalyst Nitrogen reduction reaction Density functional theory

Targeting a disintegrin and metalloprotease(ADAM)17-CD122 axis enhances CD8^(+)T cell effector differentiation and anti-tumor immunity

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

Signal Transduction and Targeted Therapy 2024年第7期9卷 3097-3111页

作者： Lina Sun Anjun Jiao Haiyan Liu Renyi Ding Ning Yuan Biao Yang Cangang zhang Xiaoxuan Jia Gang Wang Yanhong Su Dan zhang Lin Shi Chenming Sun Aijun zhang Lianjun zhang Baojun zhang Department of Pathogenic Microbiology and Immunology School of Basic Medical SciencesXi’an Jiaotong UniversityXi’anShaanxi 710061China Institute of Infection and Immunity Translational Medicine InstituteXi’an Jiaotong University Health Science CenterXi’anShaanxi 710061China Key Laboratory of Environment and Genes Related to Diseases Ministry of EducationXi’anShaanxi 710061China Xi’an Key Laboratory of Immune Related Diseases Xi’anShannxi 710061China Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy Cancer InstituteXuzhou Medical UniversityXuzhouJiangsuChina Department of Pediatrics Qilu Hospital of Shandong UniversityJinanChina National Key Laboratory of Immunity and Inflammation Suzhou Institute of Systems MedicineChinese Academy of Medical Sciences&Peking Union Medical CollegeSuzhou 215123 JiangsuChina Key Laboratory of Synthetic Biology Regulatory Elements Suzhou Institute of Systems MedicineChinese Academy of Medical Sciences&Peking Union Medical CollegeSuzhou 215123 JiangsuChina

CD8^(+)T cell immune responses are regulated by multi-layer networks,while the post-translational regulation remains largely *** ectodomain shedding is an important post-translational process orchestrating receptor expression and signal transduction through proteolytic cleavage of membrane ***,by targeting the sheddase A Disintegrin and Metalloprotease(ADAM)17,we defined a post-translational regulatory mechanism mediated by the ectodomain shedding in CD8^(+)T *** and proteomic analysis revealed the involvement of post-translational regulation in CD8^(+)T cells.T cellspecific deletion of ADAM17 led to a dramatic increase in effector CD8^(+)T cell differentiation and enhanced cytolytic effects to eliminate pathogens and ***,ADAM17 regulated CD8^(+)T cells through cleavage of membrane ***17 inhibition led to elevated CD122 expression and enhanced response to IL-2 and IL-15 stimulation in both mouse and human CD8^(+)T ***,inhibition of ADAM17 in CD8^(+)T cells improved the efficacy of chimeric antigen receptor(CAR)T cells in solid *** findings reveal a critical post-translational regulation in CD8^(+)T cells,providing a potential therapeutic strategy of targeting ADAM17 for effective anti-tumor immunity.

关键词： immunity stimulation involvement