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Comparisons of some difference forms for compressible flow in cylindrical geometry on arbitrary Lagrangian and Eulerian framework

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Applied Mathematics and Mechanics(English Edition) 2016年第11期37卷 1571-1586页

作者： Zhijun SHEN Xiao LI jian ren Institute of Applied Physics and Computational Mathematics Beijing 100088China Center for Applied Physics and Technology Peking UniversityBeijing 100071China Graduate School Chinese Academy of Engineering PhysicsBeijing 100088China

The study of cylindrically symmetric compressible fluid is interesting from both theoretical and numerical points of view. In this paper, the typical spherical sym- metry properties of the numerical schemes are discussed, and an area weighted scheme is extended from a Lagrangian method to an arbitrary Lagrangian and Eulerian （ALE） method. Numerical results are presented to compare three discrete configurations, i.e., the control volume scheme, the area weighted scheme, and the plane scheme with the addition of a geometrical source. The fact that the singularity arises from the geometri- cal source term in the plane scheme is illustrated. A suggestion for choosing the discrete formulation is given when the strong shock wave problems are simulated.

关键词： arbitrary Lagrangian and Eulerian (ALE) cylindrical geometry symmetrypreservation unstructured grid

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喷印金属微滴撞击粗糙表面的分子动力学模拟

原子与分子物理学报 2025年第4期42卷 73-80页

作者：苏仁健陈小勇游自浩桂林电子科技大学机电工程学院桂林541004 广西制造系统与先进制造技术重点实验室桂林541004

研究金属微滴撞击固体表面的行为对预测微滴形态和实现高精度的喷印制造具有重要的意义.然而,由于微纳尺度下金属微滴撞击实验的难以开展,目前涉及金属微滴撞击粗糙表面的形态变化和热毛细效应机理尚不清楚.本文采用分子动力学模拟研究... 详细信息

研究金属微滴撞击固体表面的行为对预测微滴形态和实现高精度的喷印制造具有重要的意义.然而,由于微纳尺度下金属微滴撞击实验的难以开展,目前涉及金属微滴撞击粗糙表面的形态变化和热毛细效应机理尚不清楚.本文采用分子动力学模拟研究了镓铟微滴撞击粗糙表面的动态行为,定量分析了撞击速度、粗糙结构和不同温度对微滴撞击行为的影响.结果表明:随着撞击速度的提高,微滴先后呈现沉积、弹跳和破碎飞溅三种模式,且微滴的最大铺展因子与韦伯数呈幂函数关系.此外,通过修饰基底粗糙结构发现,结构间距或高度的变化对微滴的弹跳行为存在不同的影响机制,可以有效促使或抑制微滴的弹跳行为.最后,分析得出随着温度的提高,微滴的铺展直径会变大,产生的黏性耗散也会增大.研究结果对金属微滴撞击行为的有效预测提供了理论基础.

关键词：金属微滴撞击粗糙基底分子动力学

On entire solutions of some Fermat type differential-difference equations

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 69-88页

作者： LONG jian-ren QIN Da-zhuan School of Mathematical Sciences Guizhou Normal UniversityGuiyang 550025China

On one hand,we study the existence of transcendental entire solutions with finite order of the Fermat type difference *** the other hand,we also investigate the existence and growth of solutions of nonlinear different... 详细信息

关键词： entire solutions differential-difference equations existence finite order

NUMERICAL SIMULATION OF FLOW-INDUCED VIBRATION ON TWO CIRCULAR CYLINDERS IN TANDEM ARRANGEMENT

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Journal of Hydrodynamics 2005年第6期17卷 660-666页

作者： DENG jian ren An-lu CHEN Wen-qu Department of Mechanics Zhejiang University Hangzhou 310027 China

Flow-induced vibration of two circular cylinders in tandem arrangement elastically mounted with a massspring-damping system was studied by solving the primitive variable Navier Stokes equations incorporating the Arbitrary Lagrangian-Eulerian （ALE） method. The convection term and dissipation term were discretized using the third-order upwind compact scheme and the fourth-order central compact scheme, respectively. The typical spacing between the cylinders is 4 diameters, which is close to the critical value. The dynamic response of the vibrations on two cylinders with two-degreeof-freedom motion is different from that of an isolated cylin der, and also different from that of a cylinder vibrating in the wake of a fixed upstream one. Different flow patterns were found in the wake, and proved to be relevant to the discontinuities observed in the response of the oscillatory cylinders.

关键词： flow by two cylinders flow-induced vibration high-order compact scheme dynamic response

Separate Control of High Frequency Electro-hydraulic Vibration Exciter

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 293-302页

作者： JIA Wen＇ang RUAN jian ren Yan The Key Laboratory of Mechanical Manufacture and Automation of Ministry of Education Zhejiang University of Technology Hangzhou 310032 China

The working frequency of the conventional electro-hydraulic vibration exciters,which consist of a servo valve and a hydraulic cylinder,is generally restricted within a narrow range due to limited frequency response capability of the servo valve *** counteract such restriction,a novel scheme for an electro-hydraulic vibrator,controlled by a two-dimensional valve（2D valve） and a bias valve in parallel,is therefore *** frequency,amplitude and offset are independently controlled by rotary speed,axial sliding of the spool of the 2D valve and axial sliding of the spool of the bias *** principle of separate control was presented and the regulation approach of frequency,amplitude and offset was discussed.A mathematical model of the hydraulic power mechanism for the proposed vibration exciter was established to investigate the relationship between the amplitude and the axial sliding of the 2D valve＇ spool,as well as that between the offset and the axial sliding of the bias valve＇s spool at various *** experimental system was built to validate the theoretical *** is verified that the 2D exciter is capable of working smoothly in a frequency range of 5- 200 *** its frequency,amplitude and offset can be controlled respectively by either closed loop or open loop *** is a linear relationship between the output amplitude and the spool axial opening of the 2D valve until a point when the flow rate becomes saturate and the amplitude remains *** offset displacement of the cylinder＇s piston is linearly proportional to the axial displacement of the spool of the bias valve,when the valve opening is less than 25%.Thereafter,the slop of the offset curve decreases and tends to *** proposed electro-hydraulic vibration controlled by the 2D valve not only facilitates the realization of high-frequency electro-hydraulic vibration,the high-accuracy of vibration can also be achieved by means of independent controls to the freque

关键词： control valves electro-hydraulic system vibration exciter dynamics characteristics

Application of a 3D-printed ”fistula stent” in plugging enteroatmospheric fistula with open abdomen: A case report

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World Journal of Gastroenterology 2019年第14期25卷 1775-1782页

作者： Zi-Yan Xu Hua-jian ren Jin-jian Huang Zong-An Li jian-An ren Research Institute of General Surgery Jinling Hospital School of Medicine Nanjing University NARI School of Electrical and Automation Engineering Nanjing Normal University

BACKGROUND Open abdomen(OA) has been generally accepted for its magnificent superiority and effectiveness in patients with severe trauma, severe intra-abdominal infection, and abdominal compartment syndrome. In the meantime, OA calls for a mass of nursing and the subsequent enteroatomospheric fistula(EAF), which is one of the most common complications of OA therapy, remains a thorny *** SUMMARY Our team applied thermoplastic polyurethane as a befitting material for producing a 3 D-printed "fistula stent" in the management of an EAF patient,who was initially admitted to local hospital because of abdominal pain and distension and diagnosed with bowel obstruction. After a series of operations and OA therapy, the patient developed an *** Application of this novel "fistula stent" resulted in a drastic reduction in the amount of lost enteric effluent and greatly accelerated rehabilitation processes.

关键词： 3D printing Enteroatmospheric fistula Open abdomen Isolation technique Case report

A CELL-CENTERED ALE METHOD WITH HLLC-2D RIEMANN SOLVER IN 2D CYLINDRICAL GEOMETRY

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Journal of Computational Mathematics 2021年第5期39卷 666-692页

作者： jian ren Zhijun Shen Wei Yan Guangwei Yuan Institute of Applied Physics and Computational Mathematics Beijing 100088China Center for Applied Physics and Technology HEDPSPeking UniversityBeijing 100081China

This paper presents a second-order direct arbitrary Lagrangian Eulerian(ALE)method for compressible flow in two-dimensional cylindrical *** algorithm has half-face fluxes and a nodal velocity solver,which can ensure the compatibility between edge fluxes and the nodal flow *** two-dimensional cylindrical geometry,the control volume scheme and the area-weighted scheme are used respectively,which are distinguished by the discretizations for the source term in the momentum *** two-dimensional second-order extensions of these schemes are constructed by employing the monotone upwind scheme of conservation law(MUSCL)on unstructured *** results are provided to assess the robustness and accuracy of these new schemes.

关键词： Riemann solver ALE HLLC-2D Cylindrical geometry

d-EMR:Secure and distributed Electronic Medical Record management

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High-Confidence Computing 2023年第1期3卷 47-57页

作者： Ehab Zaghloul Tongtong Li jian ren Department of Electrical and Computer Engineering Michigan State UniversityUSA

As more and more data is produced,finding a secure and efficient data access structure has become a major research *** centralized systems used by medical institutions for the management and transfer of Electronic Medical Records(EMRs)can be vulnerable to security and privacy threats,often lack interoperability,and give patients limited or no access to their own *** this paper,we first propose a privilege-based data access structure and incorporates it into an attribute-based encryption mechanism to handle the management and sharing of big data *** proposed privilege-based data access structure makes managing healthcare records using mobile healthcare devices efficient and feasible for large numbers of *** then propose a novel distributed multilevel EMR(d-EMR)management scheme,which uses blockchain to address security concerns and enables selective sharing of medical records among staff members that belong to different levels of a hierarchical *** deploy smart contracts on Ethereum blockchain and utilize a distributed storage system to alleviate the dependence on the record-generating institutions to manage and share patient *** preserve privacy of patient records,our smart contract is designed to allow patients to verify attributes prior to granting access *** provide extensive security,privacy,and evaluation analyses to show that our proposed scheme is both efficient and practical.

关键词： Privilege-based access Hierarchy Attribute-based encryption EMRs Distributed data sharing Blockchain Smart contract

The Application of HSLA Steel on Car Body

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Journal of Iron and Steel Research International 2011年第S1期18卷 718-723页

作者： BAI jian-ren (FAW Group Corportion) FAW Grp Corp Changchun Peoples R China

The role on improving the fuel economy and vehicle safety of HSLA steel was *** application of HSLA steel on car body home and abroad was briefly introduced.

关键词： HSLA The Application of HSLA Steel on Car Body FMVSS high