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NUMERICAL SIMULATION OF CELLULAR/DENDRITIC PRIMARY SPACING

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 761-766页

作者： w.q.Zhang L.Xiao DepartmentofMaterialsScienceandEngineering LiaoningTechnicalUniversityFuxin123000China

A numerical model has been established to calculate the primary spacing of cellular or dendritic structure with fluid flow considered. The computing results show that the primary spacing depends on the growing velocity, the temperature gradient on the interface and fluid flow. There is a critical growing velocity for the cell-dendrite transition, which has a relationship with the temperature gradient: Rcr = (3-4)×10-9GT. Fluid flow leads to an increase of the primary spacing for dendritic growth but a decrease for cellular growth, resulting in an instability on the interface.

关键词： primary spacing model fluid flow L/S interface

Study　on　Friction　Factor　of　Developing　and　Developed　Laminnr　Flow　in　Annular－Sector　Ducts

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Journal of Thermal Science 1995年第3期4卷 180-184页

作者： M.J. Lin w.q. tao (School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shabby 710049, China)S.S. Lue (Institute of Chemical Engineering, Southern-China University of Science and Technology, Guangzhou,Guangdong, China) School of Energy and Power Engineering Xi’an Jiaotong University Xi’an China Institute of Chemical Engineering Southern-China University of Science and Technology Guangzhou China

The pressure drops of laminar developing and developed flow in Hnnular-sector ducts with small round corner have been investigated experimentally. Numerical simulation has been performed to study the effect of the small round corner on the friction factor in the developed region. It has been found that with the increase in corner radius, the value of fRe decreases. In the range of rc/ro from 0.031 to 0.12,the decrease in fRe varies from 0.048% to 0.1% for the five apex angle computed.

关键词： laminar flow friction factor.

Mechanical properties of cocoons constructed consecutively by a single silkworm caterpillar,Bombyx mori

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Acta Mechanica Sinica 2008年第2期24卷 151-160页

作者： S.q.Huang H.P.Zhao X.q.Feng w.Cui Z.Lin M.q.Xu Department of Engineering Mechanics FML Tsinghua University Beijing 100084 China Department of Sericulture Shandong Agriculture University Tai'an 271018 China Department of Landscape Architecture Human Environment-Biological Polytechnic College. Hengyang 421005 China

Most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm caterpillar to spin two, three or four thin cocoons by taking it out from the cocoon being constructed. The mechanical properties of these cocoons were studied by static tensile tests and dynamic mechanical thermal analysis. Though external disturbances may cause the decrease in the total weight of silk spun by the silkworm, a gradual enhancement was interestingly found in the mechanical properties of these thin cocoons. Scanning electron microscopy observations of the fractured specimens of the cocoons showed that there exist several different energy dissipation mechanisms occurred simultaneously at macro-, meso-, and micro-scales, yielding a superior capacity of cocoons to adsorb the energy of possible attacks from the outside and to protect efficiently its pupa against damage. Through evolution of millions of years, therefore, the silkworm Bombyx mori seems to have gained the ability to adapt external disturbances and to redesign a new cocoon with optimized protective function when its first cocoon has been damaged for some reasons.

关键词： Silk Silkworm cocoon Mechanical property Biomimetics

Extended Thermodynamic Approach for Non-Equilibrium Gas Flow

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Communications in Computational Physics 2013年第5期13卷 1330-1356页

作者： G.H.Tang G.X.Zhai w.q.tao X.J.Gu D.R.Emerson MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049P.R.China Computational Science and Engineering Department STFC Daresbury LaboratoryWarrington WA44ADUK

Gases in microfluidic structures or devices are often in a non-equilibrium *** conventional thermodynamic models for fluids and heat transfer break down and the Navier-Stokes-Fourier equations are no longer accurate or *** this paper,the extended thermodynamic approach is employed to study the rarefied gas flow in microstructures,including the heat transfer between a parallel channel and pressure-driven Poiseuille flows through a parallel microchannel and circular *** gas flow characteristics are studied and it is shown that the heat transfer in the non-equilibrium state no longer obeys the Fourier gradient transport *** addition,the bimodal distribution of streamwise and spanwise velocity and temperature through a long circular microtube is captured for the first time.

关键词： Non-equilibrium moment method microchannel friction coefficient

Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S R wu B q wang Z w Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de Sitter BH surrounded by quintessence(RN-dSq).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dSq under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dSq are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

Improving ionic conductivity of polymer-based solid electrolytes for lithium metal batteries

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Chinese Journal of Chemical Engineering 2022年第3期35卷 202-215页

作者： q.Yang A.wang J.Luo w.Tang Key Laboratory for Green Chemical Technology of Ministry of Education State Key Laboratory of Chemical EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Because of its superior safety and excellent processability,solid polymer electrolytes(SPEs)have attracted widespread *** lithium based batteries,SPEs have great prospects in replacing leaky and flammable liquid ***,the low ionic conductivity of SPEs cannot meet the requirements of high energy density systems,which is also an important obstacle to its practical *** this respect,escalating charge carriers(***^(+))and Li^(+)transport paths are two major aspects of improving the ionic conductivity of *** article reviews recent advances from the two perspectives,and the underlying mechanism of these proposed strategies is discussed,including increasing the Li^(+)number and optimizing the Li^(+)transport paths through increasing the types and shortening the distance of Li^(+)transport *** is hoped that this article can enlighten profound thinking and open up new ways to improve the ionic conductivity of SPEs.

关键词： Solid polymer electrolyte Ion conductivity Charge carriers Transport paths Lithium battery

上海高龄体弱老人家庭亲属照顾者的生活满意度:照顾资源的作用

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人口与发展 2012年第3期18卷 74-81页

作者：楼玮群桂世勋香港大学社会工作及社会行政学系和秀圃老年研究中心华东师范大学中国现代城市研究中心上海200062

对上海城区697对75岁及以上的体弱老人及其家庭亲属照顾者作了抽样调查和统计分析。家庭亲属照顾者的照顾资源是影响高龄体弱老人生活满意度的显著因素。经济资源充分、家庭和朋友支持充足、健康自评相对好、运用积极应对策略的照顾者... 详细信息

对上海城区697对75岁及以上的体弱老人及其家庭亲属照顾者作了抽样调查和统计分析。家庭亲属照顾者的照顾资源是影响高龄体弱老人生活满意度的显著因素。经济资源充分、家庭和朋友支持充足、健康自评相对好、运用积极应对策略的照顾者有较高的生活满意度。要提升家庭亲属照顾者的心理健康,首要的任务之一是增强照顾资源,包括经济的、健康的、心理的、社会的资源。

关键词：高龄体弱老人家庭亲属照顾者照顾资源生活满意度

A novel friction stir diffusion bonding process using convex-vortex pin tools

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Journal of Materials Science & Technology 2020年第13期47卷 23-30页

作者： S.D.Ji q.wen Z.w.Li College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China State Key Laboratory of Advanced welding and Joining Harbin Institute of TechnologyHarbin 150001China

In this work,a novel friction stir diffusion bonding(FSDB)method was proposed to eliminate hook when joining thin *** tools,with several convex-vortex pins were innovatively designed to improve the diffusion bonding effect of the lap *** showed that sound joints,excellently bonded at the lap interface and without hook,were *** lap interfaces on the joints welded using the T-tool and F-tool almost remained intact,thereby indicating that they were formed by diffusion *** material flow behavior was also simulated by FLUENT software and the results showed that the material flow along thickness was significantly enhanced by increasing the pin *** joint welded by the T-tool showed shear fracture *** bonding was formed at the lap interface when using the F-tool and thus the joint showed tensile fracture.

关键词： Friction stir diffusion bonding Convex-vortex pin Hook Material flow Failure

waste Transmutation and Nuclear Energy Generation Using a Tokamak Fusion-Fission Hybrid Reactor

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High Technology Letters 1995年第1期1卷 82-86页

作者： Yican, w. Lijian, q. Academia Sinica Hefei China

A tokamak fusion-fission hybrid reactor is proposed as one of candidates for disposal of the long-lived actinides and fission product wastes and supply of future energy. To assess the feasibility of transmutation of long-lived radiowastes using fusion-fission hybrid reactors, a fusion core design is presented and several possible conceptual blankets are studied, for, respectively, actinides transmutation and fission product transmutation. The results show that actinides and fission products may be effectively transmuted using the presented hybrid reactors.

关键词： Radioactive waste Transmutation Fusion-Fission hybrid reactor