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Self-pumping ultra-thin film evaporation on CNT-embedded silicon nitride nanopore membrane

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Nano Research 2022年第3期15卷 1725-1729页

作者： Runkeng liu zhenyu liu School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The development of nanoporous membrane structure provides a potential opportunity for the advanced ultra-thin liquid film evaporation process,for which the ability of effectively and continuously maintaining the nano-thin liquid film is crucial to realize its superior *** this work,we elucidated the nanopore-based ultra-thin water film evaporation characteristics with non-equilibrium molecular dynamics simulation.A self-pumping water transport through the nanopore was observed,which is attributed to the driving force induced by the evaporation meniscus of thin liquid *** dry-out crisis will occur with the increasing membrane *** demonstrated that the hydrophobic carbon nanotube(CNT)can be utilized as the coating inside the hydrophilic silicon nitride(Si_(3)N_(4))nanopore,which reduces the flow resistance and presents an excellent capability to replenish the evaporated *** on the above findings,the internal coating of CNT is an advisable strategy for nanopore-based ultra-thin liquid film evaporation,possessing a stable high evaporation flux as well as a good mechanical strength.

关键词： thin film evaporation water nanopore coating carbon nanotube(CNT) molecular dynamics

GOVERNANCE OF GLOBAL SUPPLY CHAINS VULNERABILITY BY BUSINESS-BASED INTERORGANIZATIONAL INFORMATION PLATFORM

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Journal of Systems Science and Systems Engineering 2013年第1期22卷 1-20页

作者： zhenyu liu Weiqing ZHUANG School of Management Xiamen University

The paper introduces the business-based interorganizational information platform（IOP） and analyzes the feasibility and mechanism of business-based IOP governing global supply chains vulnerability,and then aims to develop a risk evaluation software under reliable algorithm to appraise the capability of an interorganizational information platform resisting to global supply chains risks that supports platform users and providers to make *** paper respectively starts with a basic conceptual model of global supply chains vulnerability and a conceptual model of global supply chains vulnerability in business-based IOP,and then gives the simulation model of governance of global supply chain vulnerability in business-based IOP;then has a discussion with the beneficial model of governing global supply chains vulnerability by using business-based IOP or *** results of research：（1） If given the ratio of expense per income on global supply chains using business-based IOP, we can estimate the costs to take precautions against risks that decides to the maximum value of the average income of per transaction on global supply chains using business-based IOP.（2） If given total income of transaction on global supply chains using business-based IOP,we can estimate the maximum value of the ratio of expense per income on global supply chains using business-based IOP, which would help to make pricing policy for IOP service provider.

关键词： Business-based interorganizational information platform global supply chains vulnerability governance

Motion Planning for Industrial Robots Based on Task Process Decomposition

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Chinese Journal of Mechanical Engineering 2010年第2期23卷 135-141页

作者： BU Wanghui liu zhenyu TAN Jianrong State Key Laboratory of CAD ＆ CG Zhejiang University Hangzhou 310027 China

The existing research of the industrial robotic motion planning mainly focuses on the trajectory planning and the path planning, which aim at obtaining a minimum-time trajectory and finding an obstacle-free path respectively. In the trajectory planning, the jerks of robotic joints are usually not considered, so the smoothness of the robotic motion cannot be ensured. In the path planning, the complex spatial curves generally cannot be tracked easily, and it needs the fussy teach-and-playback operation. In this paper, based on the different constraint characteristic of the variable motion phases in the practical robotic task, the complicated task is decomposed into two kinds of sub processes, which are the free motion process and the constrained motion process. In the free motion process, the kinematic models of quasi trapezoidal waveform and quasi triangular waveform are proposed with the dynamic limits of maximum velocities, accelerations and jerks of robotic joints, so the minimum-time trajectory can be obtained with the motion smoothness. In the constrained motion process, the mathematical presentation of the task paths is extracted from the CAD models of the workpieces, so the complex spatial curves can be tracked autonomously without much teaching operation. In addition to the theoretical research, a robotic virtual prototyping system is also developed for the industrial arc welding production. The proposed research ensures the robotic motion smoothness, enhances the ability for tracking the complex spatial curves, and improves the quality and efficiency of the robotic motion planning.

关键词： robotic manipulator trajectory planning path planning virtual prototyping

Influence of the finish rolling temperatures on the microstructure and texture evolution in the ferritic stainless steels

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Acta Metallurgica Sinica(English Letters) 2011年第5期24卷 343-350页

作者： Fei GAO zhenyu liu Haitao liu Guodong WANG The State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110819 China

The influence of the finish rolling temperature on the microstructure and texture evolution of Nb and B micro-alloyed ultra purified Cr17 ferritic stainless steels was investigated. The hot rolled bands were produced by conventional rolling process and the finish rolling at relatively low temperatures or ＂warm rolling＂. The microstructure was observed by optical microscopy, scanning electron microscopy and transmission electron microscopy, and X-ray diffraction was used to characterize the texture evolution processes. The results showed that as compared to conventional hot rolling process, the warm rolling has led to the refined and homogeneous microstructure and uniform recrystallization texture along γ-fiber in final sheets, indicating that the finish rolling at relatively low temperatures can be the effective way to improve significantly the formability of final sheets.

关键词： Ultra purified Cr17 ferritic stainless steel Finish rolling temperature Microstructure Texture

Shape Error Analysis of Functional Surface Based on Isogeometrical Approach

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 544-552页

作者： Pei YUAN zhenyu liu Jianrong TAN state key lab of cad&cg zhejiang universityHangzhou 310027China

The construction of traditional finite element geometry （i.e., the meshing procedure） is time consuming and creates geometric errors. The drawbacks can be over- came by the Isogeometric Analysis （IGA）, which integrates the computer aided design and structural analysis in a unified way. A new IGA beam element is developed by integrating the displacement field of the element, which is approximated by the NURBS basis, with the internal work formula of Euler-Bernoulli beam theory with the small deformation and elastic assumptions. Two cases of the strong coupling of IGA elements, ＂beam to beam＂ and ＂beam to shell＂, are also discussed. The maximum relative errors of the deformation in the three directions of can- tilever beam benchmark problem between analytical solu- tions and IGA solutions are less than 0.1%, which illustrate the good performance of the developed IGA beam element. In addition, the application of the developed IGA beam element in the Root Mean Square （RMS） error analysis of reflector antenna surface, which is a kind of typical func- tional surface whose precision is closely related to the product＇s performance, indicates that no matter how coarse the discretization is, the IGA method is able to achieve the accurate solution with less degrees of freedom than stan- dard Finite Element Analysis （FEA）. The proposed research provides an effective alternative to standard FEA for shape error analysis of functional surface.

关键词： RMS error Isogeometric analysis Euler-Bernoulli beam

A Data-driven Distributionally Robust Operational Model for Urban Integrated Energy Systems

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CSEE Journal of Power and Energy Systems 2022年第3期8卷 789-800页

作者： Hongjun Gao zhenyu liu Youbo liu Lingfeng Wang Junyong liu College of Electrical Engineering Sichuan UniversityChengdu 610065China Department of Electrical Engineering and Computer Science University of Wisconsin-MilwaukeeMilwaukeeWI 53211USA

A multi-energy conversion can effectively increase the utilization of renewable energy in the urban integrated energy system(UIES).Meanwhile,the uncertainties of renewable energy resources(e.g.,wind energy)also bring increased challenges to the operation of *** this study,a typical two-stage datadriven distributionally robust operation(DDRO)model based on finite scenarios is proposed for UIES including power,gas and heat networks to obtain a salient strategy from both an economic and robustness *** the first stage,the forecasted information for wind power is especially included to improve the economic aspect of robust *** worst probability distribution for the selected known real-time wind power scenarios can be identified in the second stage where the power differences caused by the real-time uncertainties of wind power can be mitigated by flexible regulation of energy purchasing and coupling units(such as gas turbine,power to gas equipment,electric boiler and gas boiler).Moreover,norm-1 and norm-inf co-constraints are utilized to construct a confidence set for the probability distributions of uncertain wind *** whole two-stage model is solved by the column-and-constraint generation(CCG)***,case studies are conducted to show the performance of the proposed model and various *** Terms-Data-driven methods,distributionally robust optimization,urban integrated energy system,wind power.

关键词： Data-driven methods distributionally robust optimization urban integrated energy system wind power

Numerical Modeling of Growth Kinetics of Pro-eutectoid Ferrite Transformed from Austenite in Fe-C-∑X Alloys

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Journal of Materials Science & Technology 2005年第6期21卷 795-798页

作者： zhenyu liu Guodong WANG Toshio Narita State Key Lab for Rolling Technology and Automation Northeastern University Shenyang 110004 China Lab for Interface Control Engineering Hokkaido University Sapporo Japan

In the present paper, a numerical modeling was developed to simulate the growth kinetics of ferrite transformed from austenite in Fe-C-∑X （X denotes substitution elements, such as Mn, Ni, Cr etc.） steels by solving the diffusion equation using finite difference method （FDM）. Coupled with the kinetic modeling, thermodynamic calculations were carried out to determine the γ/α phase equilibrium conditions using a para-equilibrium （PE） model. The dissipation of free energy for γ→α phase transformation due to the so-called solute drag effect （SDE） was taken into account in the thermodynamic modeling. With this modeling, simulations on the growth kinetics of ferrite in the steels containing austenite-stabilizing and ferrite-stabilizing elements （such as Ni, Mn and Si, Cr, respectively） were performed, which indicates that it deviates from the parabolic growth rate law after the initial stage of transformation. The results were compared with the experimental values given by Bradley and Aaronson, showing that this model has a reasonably good accuracy to predict the growth kinetics of ferrite.

关键词： Numerical modeling Fe-C-∑X steels γ→α phase transformation Para-equilibrium model

Objective Information Theory Exemplified in Air Traffic Control System

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Chinese Journal of Electronics 2021年第4期30卷 743-751页

作者： XU Jianfeng WANG Shuliang liu zhenyu WANG Yingfei Information Center Supreme People's Court of the People's Republic of China Institute of E-Government Beijing Institute of Technology School of Computer Science and Technology Beijing Institute of Technology School of Information Management for Law China University of Political Science and Law

Information is the core of Air traffic control system(ATCS). In this paper, objective information theory is extended to depict, model and measure the information exemplified in ATCS. The sextuple model is presented with information ontology, state occurrence time, state set, carrier, reflection time, and reflection set. The metric system is given to quantitively measure the information with extensity, detailedness, continuity,richness, containability, delay, pervasiveness, authenticity,and adaptability. The results show that the proposed method is potential to find out actual indexes in ATCS for flight safety.

关键词： Objective information theory Sextuple model Information metrics Air traffic control system

Topology Optimization of Acoustic-Mechanical Structures for Enhancing Sound Quality

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Acta Mechanica Solida Sinica 2023年第5期36卷 612-623页

作者： Lei Xu Weisheng Zhang zhenyu liu Xu Guo State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian 116023China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Sound quality is one of the essential criteria for measuring the acoustic performance of acoustic *** contrast to the optimization of sound characteristics,both the quantitative description of sound quality and the numerical instability that may occur during optimization need to be *** the present work,an explicit topology optimization approach is proposed to enhance the sound quality of acoustic-mechanical structures,where the sound quality is described,resorting to frequency response within a specified frequency *** this end,the moving morphable component(MMC)-based approach is adopted to achieve the explicit topology design,and the mixed finite element method is introduced to evaluate the sound *** the use of the explicit description of MMC,the acoustic-structure boundary can be captured accurately,which is important for acoustic response ***,a regularization topology optimization formulation is also developed to avoid the numerical issues produced in some special frequency *** examples demonstrate the effectiveness of the proposed approach in improving sound quality performance.

关键词： Acoustic-structure Topology optimization Moving morphable component(MMC) Sound performance