检索结果-南通市图书馆

Design and development of a five-axis machine tool with high accuracy,stiffness and efficiency for aero-engine casing manufacturing

引用

Chinese Journal of Aeronautics 2022年第4期35卷 485-496页

作者： yutian wang Dong wang Shizhen ZHANG Zihan TANG Liping wang Yanmin LIU State Key Laboratory of Tribology and Institute of Manufacturing Engineering Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Lab of Precision Ultraprecision Manufacturing Equipment and Control Beijing 100084China Beijing Precision Machinery&Engineering Research Co.LTD Beijing 101312China Beijing Institute of Control Engineering Beijing 100094China

In order to satisfy the machining requirements of aero-engine casing in modern aviation industry, this paper investigates three main issues during the design and development process of a five-axis machine tool with high accuracy, stiffness and efficiency, including whole structure design,key components design, and supporting stiffness design. First, an appropriate structure of five-axis machine tool is determined considering the processing characteristics of aero-engine casing. Then, a dual drive swing head and a compact motorized spindle are designed with enough drive capability and stiffness, and related structure, assembly method, cooling technology, and performance simulation are given in detail. Next, a design method of supporting stiffness of guide is proposed through the deformation prediction of the spindle end. Based on above work, a prototype of machine tool is developed, and some experiments are carried out, including performance tests of swing head and motorized spindle, and machining of a simulated workpiece of aero-engine casing. All experimental results show that the machine tool has satisfactory accuracy, stiffness and efficiency, which meets the machining requirements of aero-engine casing. The main work can be used as references for engineers and technicians, which are meaningful in practice.

关键词： Aero-engine casing manufacturing Compact motorized spindle Dual drive swing head Five-axis machine tool Supporting stiffness

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Reliability of dermatomal somatosensory-evoked potential in the evaluation of lumbosacral nerve root injury A concurrent case-control study

引用

Neural Regeneration Research 2008年第1期3卷 57-60页

作者： Ningjiang Shen Jian Chen Guangji wang Xiaoli Wu yutian wang Department of Orthopaedic Surgery Hainan Provincial People＇s Hospital Haikou 570311 Hainan Province China

BACKGROUND： It has been reported that dermatomal somatosensory evoked potential （DSEP） can be used for diagnosing nerve root injury in patients with lumbar disc herniation （LDH）, and that 83% 95% of patients suffer from the disease. Body height correction is not performed prior to determinations of latency and latency difference between the healthy and affected sides. However, latency noticeably correlates to body height. OBJECTIVE： This study aims to determine the lumbosacral nerve root injury in patients with LDH by DSEP, and to evaluate the sensitivity of the DSEP difference between the healthy and affected sides using a diagnostic index following body height correction. DESIGN： A case-control observation. SETTING： Department of Orthopedic Surgery, Hainan Provincial People＇s Hospital. PARTICIPANTS： Ninety-six patients, comprised of 67 males and 29 females, with an average age of 43 years and a mean body height of 1.65 m （range 1.48-1.81 m）, were recruited for this study. These patients suffered from unilateral lower limb radiation pain and received treatment at the Department of Orthopedic Surgery, Hainan Provincial People＇s Hospital between January 2004 and December 2006. All patients were confirmed to suffer from LDH at the L3-4, L-5, and/or Ls-SI by CT and/or MRI examinations. Central nervous system diseases were excluded. In order to obtain a normal reference value, DSEP was determined for a group of 50 subjects, who concurrently received health examinations in the same department. The subjects had no previous history of back leg pain or nervous system disease. The group of healthy controls included 26 males and 24 females, with an average age of 37 years and a mean body height of 1.63 m （range 1.50-1.80 m）. Written informed consent was obtained from all subjects for laboratory samples. The protocol was approved by the Hospital＇s Ethics Committees. DSEP was determined with myoelectricity-evoked potential equipment （Keypoint, Batch No. 9020A0042591, Dantec Com

关键词： dermatomal somatosensory evoked potential lumbar disc herniation nerve root injury

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Progress of d^0 magnetism in SiC

引用

Journal of Semiconductors 2017年第3期38卷 100-109页

作者： yutian wang Chenguang Liu Yuming Zhang School of Microelectronics Xidian University and Key Laboratory of Wide Band-Gap Semiconductor Materials and DevicesXi'an 710071 China

The properties of defect-induced ferromagnetism（d^0magnetism） in SiC belong to carbon-based material which has been systematically investigated after *** this paper,we reviewed our research progress about d^0 magnetism in two aspects,i.e.,magnetic source and magnetic coupling *** V_（Si）V_C divacancies have been evidenced as the probable source of d^0 magnetism in *** trace the ferromagnetic source in microscopic and electronic view,the p electrons of the nearest-neighbor carbon atoms,which are around the V_（Si）V_C divacancies,are *** magnetic coupling mechanism,a higher divacancy concentration leads to stronger paramagnetic interaction but not stronger ferromagnetic *** the d^0 magnetism can probably be explained as a local effect which is incapable of scaling up with the volume.

关键词： SiC d0 magnetism graphite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Improving Knowledge Graph Completion Using Soft Rules and Adversarial Learning

引用

Chinese Journal of Electronics 2021年第4期30卷 623-633页

作者： TANG Caifang RAO Yuan YU Hualei SUN Ling CHENG Jiamin wang yutian Xi'an Key Laboratory of Social Intelligence and Complexity Data Processing School of Software EngineeringXi'an Jiaotong University Shaanxi Joint Key Laboratory for Artifact Intelligence School of Software EngineeringXi'an Jiaotong University School of Software Engineering Xi'an Jiaotong University

Knowledge graph is a useful resources and tools for describing entities and relationships in natural language processing tasks. However, the existing knowledge graph are incomplete. Therefore, knowledge graph completion technology has become a research hotspot in the field of artificial intelligence, but the traditional knowledge graph embedding method does not fully take into account the role of logic rules and the effect of false negative samples on knowledge *** on the logic rules of knowledge and the role of adversarial learning in knowledge embedding, we proposes a model to improve the completion of knowledge graph:soft Rules and graph adversarial learning(RUGA). Firstly,the traditional knowledge graph embedding model is trained as generator and discriminator by using adversarial learning method, and high-quality negative samples are obtained. Then these negative samples and the existing positive samples together constitute the label triple in the injection rule model. The whole model will benefit from both high-quality samples and logical rules. In addition,we evaluated the performance of link prediction task and triple classification task on Freebase and Yago datasets respectively. Finally, the experimental results show that the model can effectively improve the effect of knowledge graph completion.

关键词： Knowledge graph Knowledge embedding Knowledge graph completion Adversarial learning

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Variations in the Microstructure and Properties of Mn-Ti Multiple-phase Steel with High Strength under Different Tempering Temperatures

引用

Chinese Journal of Mechanical Engineering 2015年第2期28卷 430-436页

作者： LI Dazhao LI Xiaonan CUI Tianxie LI Jianmin wang yutian FU Peimao School of Materials Scinece and Engineering North University of China Technology Center Taiyuan Iron & Steel (Group) Co. School of Materials Scinece and Engineering Tianjin University

There are few relevant researches on coils by tempering,and the variations of microstructure and properties of steel coil during the tempering process also remain *** using thermo-mechanical control process（TMCP）technology,Mn-Ti typical HSLA steel coils with yield strength of 920 MPa are produced on the 2250 hot rolling production ***,the samples are taken from the coils and tempered at the temperatures of 220℃,350℃,and 620℃*** tempering the strength,ductility and toughness of samples are tested,and meanwhile microstructures are *** initially emerge inside the ferrite laths and the density of the dislocation ***,the lath-shaped ferrites begin to gather,and the retained austenite films start to ***,the retained austenite films are completely decomposed into coarse and short rod-shape precipitates composed of C and Ti *** yield strength increases with increasing tempering temperature due to the pinning effect of the precipitates,and the dislocation density *** yield strength is highest when the steel is tempered at 220℃because of pinning of the precipitates to *** total elongation increases in all samples because of the development of ferrites during *** tensile strength and impact absorbed energy decline because the effect of impeding crack propagation weakens as the retained austenite films completely decompose and the precipitates *** paper clarifies the influence of different tempering temperatures on phase transformation characteristics and process of Mn-Ti typical multiphase steels,as well as its resulting performance variation rules.

关键词： multiple-phase microstructure lath-shaped ferrite polygonal ferrite precipitate retained austenite film

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

STUDY OF THE QUALITY OF GaAs THIN FILM ON Si SUBSTRATE BY X-RAY DIFFRACTION METHOD

引用

Chinese Physics Letters 1990年第7期7卷 308-311页

作者： LI Chaorong MAZhenhong CUI Shufan ZHOU Junming wang yutian Institute of Physics Academia SinicaBeijing 100080 Institute of Semiconductor Academia SinicaBeijing 100080

Different diffraction lattice planes were used to investigate the quality profiles of molecular beam epitaxy epi-layer GaAs films on Si substrate by X-ray double crystal diffraction *** the X-ray incident angle increasing,the full width of half maximum(FWHM)also increases,that is,the quality getting worse in deeper *** a clear figure of the degree of perfectness along the depth can be *** sample with strain surerlattice buffer layer has better quality than that without,especially in the surface lamella.

关键词： lattice layer RATE

来源：

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

Rare earth doping effect on the optical properties of several fluorescence materials

引用

Science China(Physics,Mechanics & Astronomy) 2012年第7期55卷 1235-1239页

作者： wang ShuTao wang DongSheng wang yutian PAN WeiWei College of Electrical Engineering Yanshan UniversityQinhuangdao 066004China Hebei Engineering University Mechanical and Electrical Institute Handan 056038China

Based on the optical properties of rare earth fluorescence materials, a set of fluorescence optical fiber systems was designed. The system selects the emitting LED, which is economical and practical as a light source. The experiment of the emission and excitation optical spectrum, decay curve of fluorescence and residuals for several sensitive materials confirms the match of Y2O2S:Eu using the light source and the feasibility of the system. The rare earth material Y2O2S:Eu is selected as the material candidate for being the most sensitive.

关键词： physics fluorescence materials optical fiber optical spectrum

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigation of MHD power generation with supersonic non-equilibrium RF discharge

引用

Chinese Journal of Aeronautics 2016年第4期29卷 855-862页

作者： Yang Pengyu Zhang Bailing Li Yiwen wang yutian Duan Chengduo Fan Hao Gao Ling Science and Technology on Plasma Dynamics Laboratory Air Force Engineering University China Aerodynamics Research and Development Center Science and Technology on Combustion Internal Flow and Thermo-Structure Laboratory Astronautics School Northwestern Polytechnical University

Magnetohydrodynamic (MHD) power generation with supersonic non-equilibrium plasma is demonstrated. Capacitively coupled radio frequency (RF) discharge (6 MHz, maximum continual power output of 200 W) was adopted to ionize the Mach number 3.5 (650 m/s), 0.023 kg/m(3) airflow. In a MHD channel of 16 mm x 10 mm x 20 mm, MHD open voltage of 10 V is realized in the magnetic field of 1.25 T, and power of 0.12 mW is extracted steadily and continuously in the magnetic field of 1 T. The reasons for limited power generation are proposed as: low conductivity of RF discharge; large touch resistance between MHD electrode and plasma; strong current eddies due to flow boundary layer. In addition, the cathode voltage fall is too low to have obvious effects on MHD power generation. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd.

关键词： Magnetohydrodynamic Non-equilibrium plasma Power generation Radio frequency discharge Supersonic flow

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigation of C_(60) Single Crystal by X-Ray Methods

引用

Chinese Physics Letters 1995年第4期12卷 217-220页

作者： LI Chaorong MAI Zhenhong wang Gang wang yutian WU Lansheng CUI Shufan XIE Sishen JIANG Jianhua Institute of Physics Academia SinicaBeijing 100080 Institute of Semiconductors Academia SinicaBeijing 100083 Beijing Synchrotron Radiation Laboratory P.O.Box 918Beijing 100039

C_(60) single crystals grown by a single-temperature-gradient technique were characterized by synchrotron radiation white beam x-ray topography and x-ray double crystal diffraction with Cu K_(α1) radiation on conventional x-ray *** results show that the crystal is rather well *** x-ray topographies give an evidence of dendritic growth mechanism of C_(60) single crystal,and x-ray double crystal diffraction rocking curve shows that there are mosaic structural defects in the sample.A phase transition at 249±1.5K from a simple cubic to a face centered cubic structure is confirmed by in situ observation of synchrotron radiation white beam x-ray topography with the temperature varing from 230 to 295K.

关键词： cubic topography crystal

来源：

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

IGF2BPs as novel m^(6)A readers:Diverse roles in regulating cancer cell biological functions,hypoxia adaptation,metabolism,and immunosuppressive tumor microenvironment

引用

Genes & Diseases 2024年第2期11卷 890-920页

作者： Meiqi Duan Haiyang Liu Shasha Xu Zhi Yang Fusheng Zhang Guang wang yutian wang Shan Zhao Xiaofeng Jiang Department of General Surgery The Fourth Affiliated Hospital of China Medical UniversityShenyangLiaoning 110032China Department of Gastroendoscopy The Fourth Affiliated Hospital of China Medical UniversityShenyangLiaoning 110032China Department of Rheumatology and Immunology The First Affiliated Hospital of China Medical UniversityShenyangLiaoning 110002China

m^(6)A methylation is the most frequent modification of mRNA in eukaryotes and plays a crucial role in cancer progression by regulating biological ***-like growth factor 2 mRNA-binding proteins(IGF2BP)are newly identified m^(6)A‘readers’.They belong to a family of RNA-binding proteins,which bind to the m^(6)A sites on different RNA sequences and stabilize them to promote cancer *** this review,we summarize the mechanisms by which different upstream factors regulate IGF2BP in *** current literature analyzed here reveals that the IGF2BP family proteins promote cancer cell proliferation,survival,and chemoresistance,inhibit apoptosis,and are also associated with cancer glycolysis,angiogenesis,and the immune response in the tumor ***,with the discovery of their role as‘readers’of m^(6)A and the characteristic re-expression of IGF2BPs in cancers,it is important to elucidate their mechanism of action in the immunosuppressive tumor *** also describe in detail the regulatory and interaction network of the IGF2BP family in downstream target RNAs and discuss their potential clinical applications as diagnostic and prognostic markers,as well as recent advances in IGF2BP biology and associated therapeutic value.

关键词： Cancer IGF2BP Immunosuppressive TME m^(6)A Molecular mechanism Therapy

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：