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Thermoelastohydrodynamic behaviour of inclined-ellipse dimpled gas face seals

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Science China(Technological Sciences) 2017年第4期60卷 529-537页

作者： DING ShaoPeng bai ShaoXian College of Mechanical Engineering Zhejiang University of Technology Hangzhou 310032 China

The thermoelastohydrodynamic performance of an inclined-ellipse dimpled gas face seal is analyzed. The pressure distributions of the gas film and temperature fields of the seal rings and gas film are presented considering thermal and elastic ***, the influences of texturing parameters, including dimple inclination angle and dimple depth, on sealing performance are investigated under different operating parameters such as rotational speeds and seal pressures. The results show that face distortions lead to a decrease in the hydrodynamic effect at high rotational speed. The analysis shows that the opening force can decrease by more than 50% as the rotational speed increases from 0 to 35000 r min^(-1). The influence of face distortion on the seal performance, such as opening force and leakage characteristic, gradually increases with the rotational speed.

关键词： thermoelastohydrodynamic effect elastic and thermal distortions inclined-ellipse dimple seal performance

THE RESTRICTIVELY PRECONDITIONED CONJUGATE GRADIENT METHODS ON NORMAL RESIDUAL FOR BLOCK TWO-BY-TWO LINEAR SYSTEMS

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Journal of Computational Mathematics 2008年第2期26卷 240-249页

作者： Junfeng Yin Zhongzhi bai LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

The restrictively preconditioned conjugate gradient （RPCG） method is further developed to solve large sparse system of linear equations of a block two-by-two structure. The basic idea of this new approach is that we apply the RPCG method to the normal-residual equation of the block two-by-two linear system and construct each required approximate matrix by making use of the incomplete orthogonal factorization of the involved matrix blocks. Numerical experiments show that the new method, called the restrictively preconditioned conjugate gradient on normal residual （RPCGNR）, is more robust and effective than either the known RPCG method or the standard conjugate gradient on normal residual （CGNR） method when being used for solving the large sparse saddle point problems.

关键词： Block two-by-two linear system Saddle point problem Restrictively preconditioned conjugate gradient method Normal-residual equation Incomplete orthogonal factorization

ON THE CONVERGENCE OF THE RELAXATION METHODS FOR POSITIVE DEFINITE LINEAR SYSTEMS

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Journal of Computational Mathematics 1998年第6期16卷 527-538页

作者： bai, ZZ Huang, TZ Chinese Acad Sci ICMSEC Beijing 100080 Peoples R China Univ Elect Sci & Technol China Dept Appl Math Chengdu 610054 Peoples R China

We establish the convergence theories of the symmetric relaxation methods for the system of linear equations with symmetric positive definite coefficient matrix, and more generally, those of the unsymmetric relaxation... 详细信息

关键词： system of linear equations relaxation method convergence theory positive definite matrix

Distributed Collaborative Response Surface Method for Mechanical Dynamic Assembly Reliability Design

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1160-1168页

作者： bai Guangchen FEI Chengwei School of Energy and Power Engineering Beihang University

Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the randomness from a probabilistic perspective. To improve the accuracy and efficiency of dynamic assembly relationship reliability analysis, the mechanical dynamic assembly reliability（MDAR） theory and a distributed collaborative response surface method（DCRSM） are proposed. The mathematic model of DCRSM is established based on the quadratic response surface function, and verified by the assembly relationship reliability analysis of aeroengine high pressure turbine（HPT） blade-tip radial running clearance（BTRRC）. Through the comparison of the DCRSM, traditional response surface method（RSM） and Monte Carlo Method（MCM）, the results show that the DCRSM is not able to accomplish the computational task which is impossible for the other methods when the number of simulation is more than 100 000 times, but also the computational precision for the DCRSM is basically consistent with the MCM and improved by 0.40-4.63% to the RSM, furthermore, the computational efficiency of DCRSM is up to about 188 times of the MCM and 55 times of the RSM under 10000 times simulations. The DCRSM is demonstrated to be a feasible and effective approach for markedly improving the computational efficiency and accuracy of MDAR analysis. Thus, the proposed research provides the promising theory and method for the MDAR design and optimization, and opens a novel research direction of probabilistic analysis for developing the high-performance and high-reliability of aeroengine.

关键词： machinery dynamic assembly reliability analysis distributed collaborative response surface method,blade-tip radial running clearance

Atom-efficient coupling reaction of aryl bromides with sodium tetraphenylborate catalyzed by reusable Pd/C in water under focused microwave irradiation

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Chinese Chemical Letters 2009年第2期20卷 158-160页

作者： Lin bai Institute of Green Chemistry Experiment and Teaching Lanzhou City University Lanzhou 730070 China

A rapid and heterogeneous Pd/C-catalyzed atom-efficient phenylation of aryl bromides by sodium tetraphenylborate takes place under focused microwave irradiation in water. The palladium catalyst can be easily recovered... 详细信息

关键词： Pd/C Sodium tetraphenylborate Water Focused microwave irradiation

New Method to Improve Dynamic Stiffness of Electro-hydraulic Servo Systems

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 997-1005页

作者： bai Yanhong QUAN Long Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology School of Electronics Information Engineering Taiyuan University of Science and Technology

Most current researches working on improving stiffness focus on the application of control *** controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so the control action is *** dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control *** this paper,the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is *** this basis,the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put *** a scheme using double servo valves to realize flow feedforward compensation is presented,in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in *** two valves are arranged in parallel to control the cylinder ***,the model of flow compensation is derived,by which the product of the amplitude and width of the valve’s pulse command signal can be *** determination rules of the amplitude and width of pulse signal are concluded by analysis and *** the proposed scheme,simulations and experiments at different positions with different force changes are *** simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling *** is,system dynamic load stiffness is evidently *** paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.

关键词： electro-hydraulic servo system flow feedforward compensation dynamic load stiffness double-valve actuation

基于CNCSCOLOR 的色相色调感性模型构建

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丝绸 2025年第1期62卷 1页

作者：薛媛白圆圆姜茸凡西安工程大学服装与艺术设计学院

中国应用色彩体系(CNCSCOLOR)基于中国人眼视觉实验所开发，但在国外色彩体系的早期市场占有下没有得到广泛应用。本研究尝试开发一套易于学习推广的模型，以促进其普及和应用。首先通过对三维色彩体系的研究分析，借鉴日本PCCS色彩体... 详细信息

中国应用色彩体系(CNCSCOLOR)基于中国人眼视觉实验所开发，但在国外色彩体系的早期市场占有下没有得到广泛应用。本研究尝试开发一套易于学习推广的模型，以促进其普及和应用。首先通过对三维色彩体系的研究分析，借鉴日本PCCS色彩体系，构建了简化的二维色相-色调基本模型，其中色调融合了色彩属性明度和彩度。模型用直角坐标定位，水平轴为彩度，垂直轴为明度，5种无彩色将明度轴分为四段，12个20色色相环即12种有彩色色调，按照明度与彩度的大小有序分布于平面内。确定构成基本模型的240种有彩色和5种无彩色的选色规则，选出色彩，组合完善基本模型。其次，研究确定12种有彩色色调的感性，得到色相-色调感性模型。通过主观调查初步分析得到有彩色色调的感性，再实施客观眼动实验进一步验证调查结果，最终确定12个有彩色色调的感性分别是鲜明的、明快的、强烈的、浑厚的、清新的、淡雅的、浑浊的、厚重的、浅淡的、暗淡的、灰暗的、黑暗的。研究得到的色相-色调模型包含的色彩数量少，采用二维的平面布局，使初学者易懂易记，便于普及应用；且色调命名符合中国人的情感特征，将用于后续的感性配色模型构建，便于设计师和消费者快速进行精准的产品色彩搭配，对中国本土色彩体系的发展和色彩设计水平的提升具有实际的应用价值。

关键词： CNCSCOLOR PCCS色彩体系色相-色调基本模型色相-色调感性模型主观调查眼动实验

Digital twin-based sustainable intelligent manufacturing: a review

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Advances in Manufacturing 2021年第1期9卷 1-21页

作者： Bin He Kai-Jian bai Shanghai Key Laboratory of Intelligent Manufacturing and Robotics School of Mechatronic Engineering and AutomationShanghai UniversityShanghai 200444People's Republic of China

As the next-generation manufacturing system,intelligent manufacturing enables better quality,higher productivity,lower cost,and increased manufacturing *** concept of sustainability is receiving increasing attention,and sustainable manufacturing is *** digital twin is an emerging technology used in intelligent manufacturing that can grasp the state of intelligent manufacturing systems in real-time and predict system *** intelligent manufacturing based on a digital twin has advantages in practical *** fully understand the intelligent manufacturing that provides the digital twin,this study reviews both technologies and discusses the sustainability of intelligent ***,the relevant content of intelligent manufacturing,including intelligent manufacturing equipment,systems,and services,is *** addition,thesustainability of intelligent manufacturing is ***,a digital twin and its application are introduced along with the development of intelligent manufacturing based on the digital twin ***,combined with the current status,the future development direction of intelligent manufacturing is presented.

关键词： Intelligent manufacturing Digital twin Advanced manufacturing Industry 4.0 Sustainable manufacturing

Dirac Optical Potential of p-^14Be and Pronounced “Long-Tail” Shape

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Communications in Theoretical Physics 2005年第2X期44卷 337-342页

作者： GU bai-Ping Department of Physics Nanjing University Nanjing 210008 China Department of Mathematics and Physics Nanjing University of Traditional Chinese Medicine Nanjing 210029 China Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China

The Dirac optical potential for p-14Be elastic scattering is evaluated by the relativistic impulse approximation. Each of the real part and the imaginary part of the potential shows a pronounced "long tail" for the proton elastic scattering from halo nucleus 14Be compared with the potentials for proton scattering from its adjacent nuclei 12C and 16O, which do not have halo structures. This kind of "long tail" phenomenon suggests another signature for halo nuclei.

关键词： RMF theory halo nuclei proton elastic scattering RIA Dirac optical potential