检索结果-南通市图书馆

Improved Stiffness Modeling for An Exechon‑Like Parallel Kinematic Machine(PKM)and Its Application

Chinese Journal of Mechanical Engineering 2020年第3期33卷 130-141页

作者： Nanyan Shen Liang Geng Jing Li Fei ye zhuang Yu Zirui Wang Shanghai Key Laboratory of Intelligent Manufacturing and Robotics Shanghai UniversityShanghai 200444China School of Mechatronic Engineering and Automation Shanghai UniversityShanghaiChina.

Hole drilling or contour milling for the large and complex workpieces such as automobile panels and aircraft fuselages makes a high combined demand on machining accuracy,stiffness and workspace of machining ***,a 5-DOF(degrees of freedom)parallel kinematic machine(PKM)with redundant constraints is *** on the kinematics analysis of the parallel mechanism using intermediate variables,the kinematics problems of the PKM are solved through equivalent kinematics *** structural stiffness matrix method is adopted to model the stiffness of the parallel mechanism of the PKM,where the stiffness of each joint and branch component is obtained by stiffness formula and finite element *** the stiffness model of the parallel mechanism is improved by correction coefficient matrix,each element of which is constructed as a polynomial function of three independent end variables of the parallel *** terminal stiffness matrices obtained by simulation result are used to determine the coefficients of polynomial function by least square fitting to describe the correction coefficient over the workspace of the parallel mechanism *** experiment results prove that the modification method can greatly improve the stiffness model of the parallel *** enhance the machining accuracy of the PKM,the proposed kinematics model and the improved stiffness model are utilized to optimize the working stiffness of parallel machine by searching the best relative position of parallel machine and workpiece.A plate workpiece taken as example is examined in the case study section,which demonstrates the effectiveness of optimization method.

关键词： PKM 5-DOF Equivalent kinematics model Intermediate variables Stiffness correction coefficient Optimal working 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

Mechanical properties and thermal deformation behavior of low-cost titanium matrix composites prepared by a structure-optimized Y_(2)O_(3) crucible

引用

Journal of Iron and Steel Research International 2024年第3期31卷 738-751页

作者： Qian Dang Gang Huang ye Wang Chi Zhang Guo-huai Liu Zhao-dong Wang The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150004HeilongjiangChina School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina

A porous yttrium oxide crucible with both thermal shock resistance and erosion resistance was developed by structural *** structure-optimized yttrium oxide crucible was proved to be suitable for melting highly reactive titanium ***-cost(TiB+Y2O_(3))-reinforced titanium matrix composites were prepared by vacuum induction melting using the prepared *** thermal deformation behavior and microstructure evolution of(TiB+Y2O_(3))-reinforced tita-nium matrix composites were investigated at deformation temperatures of 900-1100℃with strain rates of 0.001-1 *** results showed that the prepared yttrium oxide crucible had both thermal shock and erosion resistance,the low-cost titanium matrix composites could be prepared by the developed yttrium oxide crucibles which were homogeneous in composition and highly sensitive to strain rate and deformation temperature,and the peak and theological stresses decreased with increasing deformation temperature or decreasing strain *** addition,the average thermal deformation activation energy of the composites was calculated to be 574.6 kJ/mol by establishing the Arrhenius constitutive equation in consideration of the strain variables,and the fitting goodness between the predicted stress value and the measured value was 97.624%.The calculated analysis of the hot processing map showed that the best stable thermal deformation zone was located in the deformation temperature range of 1000-1100℃and strain rate range of 0.001-0.01 s^(-1),where the peak dissipation coefficient wasη=71%.In this zone,the deformation of the reinforcement and matrix was harmonious,the reinforcement was less likely to fracture,dynamic recrystallization occurred more fully and the alloy exhibited near steady rheological characteristics.

关键词： Yttrium oxide crucible Titanium matrix composite Thermal deformation behavior Constitutive equation Hot processing map Microstructure evolution

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

Low-amplitude structure recognition method based on non-subsampled contourlet transform

引用

Petroleum Science 2024年第5期21卷 3062-3078页

作者： Fen Lyu Xing-ye Liu Li Chen Chao Li Jie Zhou huai-Lai Zhou Key Lab of Earth Exploration&Information Techniques of Ministry of Education Chengdu University of TechnologyChengdu610059SichuanChina College of Geophysics Chengdu University of TechnologyChengdu610059SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu610059SichuanChina Postdoctoral Research Station of the School of Geophysics Chengdu University of TechnologyChengdu610059SichuanChina

Currently, horizontal well fracturing is indispensable for shale gas development. Due to the variable reservoir formation morphology, the drilling trajectory often deviates from the high-quality reservoir,which increases the risk of fracturing. Accurately recognizing low-amplitude structures plays a crucial role in guiding horizontal wells. However, existing methods have low recognition accuracy, and are difficult to meet actual production demand. In order to improve the drilling encounter rate of high-quality reservoirs, we propose a method for fine recognition of low-amplitude structures based on the non-subsampled contourlet transform(NSCT). Firstly, the seismic structural data are analyzed at multiple scales and directions using the NSCT and decomposed into low-frequency and high-frequency structural components. Then, the signal of each component is reconstructed to eliminate the low-frequency background of the structure, highlight the structure and texture information, and recognize the low-amplitude structure from it. Finally, we combined the drilled horizontal wells to verify the low-amplitude structural recognition results. Taking a study area in the west Sichuan Basin block as an example, we demonstrate the fine identification of low-amplitude structures based on NSCT. By combining the variation characteristics of logging curves, such as organic carbon content(TOC), natural gamma value(GR), etc., the real structure type is verified and determined, and the false structures in the recognition results are checked. The proposed method can provide reliable information on low-amplitude structures for optimizing the trajectory of horizontal wells. Compared with identification methods based on traditional wavelet transform and curvelet transform, NSCT enhances the local features of low-amplitude structures and achieves finer mapping of low-amplitude structures, showing promise for application.

关键词： Shale gas Low-amplitude structure Low-frequency background Non-subsampled contourlet transform Horizontal well verification

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

Immobilization of chiral Rh catalyst on glass and application to asymmetric transfer hydrogenation of aryl ketones in aqueous media

引用

Chinese Chemical Letters 2014年第4期25卷 613-616页

作者： Tan-Yu Cheng Jing-Lan zhuang Hui Yao huai-Sheng Zhang Guo-Hua Liu Key Laboratory of Resource Chemistry of Ministry of Education College of Life and Environmental ScienceShanghai Normal University

A chiral catalyst, Cp＊RhTsDPEN （Cp＊ = pentamethyl cyclopentadiene, TsDPEN = substitutive phenylsulfonyl-l,2-diphenylethylenediamine）, was synthesized and immobilized at the surface of glass. The immobilized catalyst exhibited good catalytic efficiency for asymmetric transfer hydrogenation of aromatic ketones in water with HCOONa as hydrogen source.

关键词： Heterogeneous Rh catalyst Asymmetric transfer hydrogenation Aromatic ketones Glass suhstrate

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

Optimization of investment casting process for K477 superalloy aero-engine turbine nozzle by simulation and experiment

引用

China Foundry 2022年第4期19卷 351-358页

作者： Xin Hao Guo-huai Liu ye Wang Shi-ping Wu Zhao-dong Wang AECC South Industry Company Limited Zhuzhou 412002HunanChina State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

In order to reduce the shrinkage porosity of nickel-based superalloy castings in the investment casting process,the effects of different gating systems on mold filling,solidification process,and prediction of shrinkage porosity of aero-engine turbine nozzle castings were investigated by simulation and experimental *** show that the design of the vertical runner would cause greater turbulence of the melt in the riser during the mold filling process,and the outer runner is not *** the decrease in number of runners,the hot spot moves down towards the casting,and the shrinkage and porosity defects are formed in the casting below the *** the original designs,a certain tendency of shrinkage and porosity defect is found in the vanes,inner rings,and outer rings of the castings by both simulation prediction and ***,based on the processing optimization,the aero-engine turbine nozzle casting with no shrinkage and porosity defects is obtained.

关键词： nickel-based superalloy investment casting shrinkage porosity simulation optimization

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

Discriminating High-Pressure Water Phases Using Rare-Event Determined Ionic Dynamical Properties

引用

Chinese Physics Letters 2020年第4期37卷 19-25页

作者： Lin zhuang Qijun ye Ding Pan Xin-Zheng Li Institute of Condensed A latter and Alat erial Physics School of PhysicsPeking UniversityBeijing 100871 State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Frontier Science Center for Nano-optoelectronics and School of PhysicsPeking UniversityBeijing 100871 Department of Physics and Department of Chemistry Hong Kong University of Science and TechnologyHong Kong HKUST Fok Ying Tiling Research Institute Guangzhou 511458 Collaborative Innovation Center of Quantum Matter Peking UniversityBeijing 100871

Recent discoveries of dynamic ice Ⅶ and superionic ice highlight the importance of ionic diffusions in discriminating high-pressure(P) water *** rare event nature and the chemical bond breaking associated with these diffusions,however,make extensive simulations of these processes unpractical to ab initio and inappropriate for force field based *** a first-principles neural network potential,we performed a theoretical study of water at 5-70 GPa and 300-3000 ***-time dynamics of protons and oxygens were found indispensable in discriminating several subtle states of water,characterized by proton’s and oxygen ion’s diffusion coefficients and the distribution of proton’s *** dynamic ice Ⅶ,two types of proton transfer mechanisms,i.e.,translational and rotational transfers,were identified to discriminate this region further into dynamic ice Ⅶ T and dynamic ice Ⅶ *** triple point between ice Ⅶ,superlonic ice(SI),and liquid exists because the loosening of the bee oxygen skeleton is prevented by the decrease of interatomic distances at high P’*** melting of ice Ⅶ above ~40 GPa can be understood as a process of two individual steps:the melting of protons and the retarded melting of oxygens,responsible for the forming of *** boundary of the dynamic ice VIF and SI lies on the continuation line ice Ⅶ’s melting curve at low P’*** on these,a detailed phase diagram is given,which may shed light on studies of water under P’s in a wide range of interdisciplinary sciences.

关键词： Rare continuation steps

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

Facile and green route to highly luminescent ZnS-shelled CdSe nanocrystals

引用

Rare Metals 2009年第2期28卷 107-111页

作者： ye Xinyua zhuang Weidong Hu Yunsheng Luo Xinyu Zhao Chunlei Huang Xiaowei Gen Res Inst NonFerrous Met Natl Engn Res Ctr Rare Earth Mat Beijing 100088 Peoples R China Grirem Adv Mat Co Ltd Beijing 100088 Peoples R China Jiangxi Univ Sci & Technol Sch Mat & Chem Engn Ganzhou 341000 Peoples R China

Highly luminescent CdSe/ZnS nanocrystals were obtained by adapting non-TOP-based synthesis and a subsequent two-phase ZnS shelling procedure:the core CdSe nanocrystals were synthesized in sole solvent paraffin liquid with cadmium oxide,elemental sele-nium,and oleic acid; the deposition of the ZnS shell was conducted by using zinc stearate in toluene and sodium sulfide in deionized water. The green and low-cost route was proved to be more efficient to constrain the size of core nanocrystals while tuning the ...

关键词： crystal structure characterization solvent growth from solution nanomaterials CdSe/ZnS

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

An optimized perforation clusters spacing model based on the frictional shale layer’s debonding

引用

Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 142-145页

作者： Tao Wang Xuan ye ZhanLi Liu Yue Gao Zhuo zhuang School of Aerospace Engineering Tsinghua University

The success of hydraulic fracturing for shale gas recovery has motivated much research interest in understanding the underlying mechanisms (1-3)When hydraulic fractures (HFs) expand, multiple cracks and crack branches... 详细信息

关键词： An optimized perforation clusters spacing model based on the frictional shale layer’s debonding SRV

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

High-order time-reversal symmetry breaking normal state

引用

Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 136-148页

作者： Meng Zeng Lun-Hui Hu Hong-ye Hu Yi-zhuang You Congjun Wu Department of Physics University of CaliforniaSan DiegoCalifornia 92093USA Department of Physics Zhejiang UniversityHangzhou 310058China New Cornerstone Science Laboratory Department of PhysicsSchoolof ScienceWestlake UniversityHangzhou 30024China Institute for Theoretical Sciences Westlake UniversityHangzhou 310024China Key Laboratory for Quantum Materials of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310024China

Spontaneous time-reversal symmetry breaking plays an important role in studying strongly correlated unconventional *** two superconducting gap functions with different symmetries compete,the relative phase channel(θ_(-)≡θ_(1)-θ_(2))exhibits an Ising-type Z_(2) symmetry due to the second order Josephson coupling,where θ_(1,2) are the phases of two gap *** contrast,the U(1) symmetry in the channel of θ_(+)≡(θ_(1)+θ_(2))/2 is *** phase locking,i.e.,ordering of θ_(-),can take place in the phase fluctuation regime before the onset of superconductivity,i.e.,when θ_(+) is *** θ_(-) is pinned at ±π/2,then timereversal symmetry is broken in the normal state,otherwise,if θ_(-)=0,or,π,rotational symmetry is broken,leading to a nematic normal *** both cases,the order parameters possess a 4-fermion structure beyond the scope of mean-field theory,which can be viewed as a high order symmetry *** employ an effective two-component XY-model assisted by a renormalization group analysis to address this *** a natural by-product,we also find the other interesting intermediate phase corresponds to ordering of θ_+ but with θ_(-)*** is the quartetting,or,charge-4e,superconductivity,which occurs above the low temperature Z_(2)-breaking charge-2e superconducting *** results provide useful guidance for studying novel symmetry breaking phases in strongly correlated superconductors.

关键词： superconductivity strong correlation time-reversal breaking charge-4e

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

Advances on Na-K liquid alloy-based batteries

引用

Journal of Energy Chemistry 2022年第8期31卷 313-323,I0009页

作者： Junwei Wu zhuang Xue Lixuan Yuan Jilei ye Qinghong Huang Lijun Fu Yuping Wu State Key Laboratory of Materials-Oriented Chemical Engineering College of Energy Science and EngineeringNanjing Tech UniversityNanjing 211816JiangsuChina

Sodium-potassium(Na^(-)K)liquid alloys attract increasing research attention,as an ideal alternative of Li metal for metal-based batteries,attributing to their high abundance,low redox potential,high capacity,and dendrite-free *** addition,the liquid and self-healing features of Na^(-)K alloys endow good electrode/electrolyte interfacial *** recent advances on the Na^(-)K liquid alloy-based batteries(NKBs)are reviewed *** anode designs for immobilization of the liquid alloy are *** influences of the electrolyte and cathode materials on the battery performances are *** addition,considering the co-existence of both K^(+)and Na^(+)in the electrolyte,the working mechanisms of the NKBs are *** also show that despite the improvement,challenges of the NKBs *** compatibility between Na^(-)K liquid alloy and electrolyte,as well as disputed working mechanisms,request detailed surface analyses of the liquid alloy and local element distribution evolution in the *** review would shed light on the fundamental understanding of Na^(-)K alloy electrochemistry and the development of dendrite-free metal-based energy storage systems with high energy density.

关键词： Sodium-potassium alloy Liquid anode Metal battery Dendrite-free Mechanism

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

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：