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| 1 | Analysis and Numerical Simulation of Rolling Contact between Sphere and Cone显示文摘In non-conforming rolling contact, the contact stress is highly concentrated in the contact area. However, there are some limitations of the special contact model and stress model used for the theoretical study of the phenomenon, and this has prevented in-depth analysis of the associated friction, wear, and failure. This paper is particularly aimed at investigating the area of rolling contact between a sphere and a cone, for which purpose the boundary is determined by the Hertz theory and the geometries of the non-conforming surfaces. The phenomenon of stick-slip contact is observed to occur in the contact area under the condition of no-full-slip(Q < μ·P). Using the two-dimensional rolling contact theory developed by CARTER, the relative positions of the stick and slip regions and the distribution of the tangential force over the contact area are analyzed. Furthermore, each stress component is calculated based on the Mc Ewen theory and the idea of narrow band. The stress equations for the three-dimensional rolling contact between the sphere and the cone are obtained by the principle of superposition, and are used to perform some numerical simulations. The results show that the stress components have a large gradient along the boundary between the stick and slip regions, and that the maximum stress is inversely proportional to the contact coefficient and proportional to the friction coefficient. A new method for investigating the stress during non-classical three-dimensional rolling contact is proposed as a theoretical foundation for the analysis of the associated friction, wear, and failure. | ZHAO Yanling XIA Chengtao WANG Hongbo XUAN Jiaping XIANG Jingzhong LIU Xianli SU Xiangguo | 2015 | Chinese Journal of Mechanical Engineering2015，28，3： | 18 |
| 2 | Grain boundary engineering with nano-scale InSb producing high performance In_(x)Ce_(y)Co_(4)Sb_(12+z)skutterudite thermoelectrics显示文摘Thermoelectric semiconductors based on CoSb_(3)hold the best promise for recovering industrial or automotive waste heat because of their high efficiency and relatively abundant,lead-free constituent elements.However,higher efficiency is needed before thermoelectrics reach economic viability for widespread use.In this study,n-type In_(x)Ce_(y)Co_(4)Sb_(12+z)skutterudites with high thermoelectric performance are produced by combining several phonon scattering mechanisms in a panoscopic synthesis.Using melt spinning followed by spark plasma sintering(MS-SPS),bulk In_(x)Ce_(y)Co_(4)Sb_(12+z)alloys are formed with grain boundaries decorated with nano-phase of InSb.The skutterudite matrix has grains on a scale of 100-200 nm and the InSb nano-phase with a typical size of 5e15 nm is evenly dispersed at the grain boundaries of the skutterudite matrix.Coupled with the presence of defects on the Sb sublattice,this multi-scale nanometer structure is exceptionally effective in scattering phonons and,therefore,InxCey-Co_(4)Sb_(12)/InSb nano-composites have very low lattice thermal conductivity and high zT values reaching in excess of 1.5 at 800 K. | Han Li Xianli Su Xinfeng Tang Qingjie Zhang Ctirad Uher G.Jeffrey Snyder Umut Aydemir | 2017 | Journal of Materiomics2017，3，4： | 7 |
| 3 | Realization of non-equilibrium process for high thermoelectric performance Sb-doped Ge Te显示文摘Pristine GeTe shows inferior thermoelectric performance around unit due to the large carrier concentration induced by the presence of intrinsic high concentration of Ge vacancy. In this study, we report a thermoelectric figure of merit ZT of 1.56 at 700 K, realized in Sb-doped GeTe based thermoelectric(TE)materials via combined effect of suppression of intrinsic Ge vacancy and Sb doping. The nonequilibrium nature during melt spinning process plays very important role. For one thing, it promotes the homogeneity in Ge_(1-x)Sb_xTe samples and refines the grain size of the product. Moreover the persistent Ge precipitated as impurity phase in the traditional synthesis process is found to be dissolved back into the GeTe sublattice, accompanying with a drastic suppression of Ge vacancies concentration which in combination with Sb electron doping significantly reduced the inherent carrier concentration in GeTe.Low carrier concentration, approaching the optimum carrier concentration ~3.74 × 10^(-20) cm^(-3) and a high power factor of 4.01 × 10^(-3) W m^(-1)K^(-2) at 750 K are achieved for Ge_(0.98)Sb_(0.02) Te sample. In addition,the enhanced grain boundary phonon scattering by refining the grain size through melt spinning(MS)process, coupled with the intensified alloying phonon scattering via Sb doping leads to low thermal conductivity of 1.53 W m^(-1) K^(-1) at 700 K for Ge_(0.94) Sb_(0.06) Te sample. All those contribute to a high ZT value,representing over 50% improvement in the ZT value compared to the Sb free samples, which provides an alternative way for ultrafast synthesis of high performance GeTe based thermoelectric material. | Evariste Nshimyimana Xianli Su Hongyao Xie Wei Liu Rigui Deng Tingting Luo Yonggao Yan Xinfeng Tang | 2018 | Science Bulletin2018，63，11： | 6 |
| 4 | Nonequilibrium effects of reactive fiow based on gas kinetic theory显示文摘How to accurately probe chemically reactive fiows with essential thermodynamic nonequilibrium effects is an open issue.Via the Chapman–Enskog analysis,the local nonequilibrium particle velocity distribution function is derived from the gas kinetic theory.It is demonstrated theoretically and numerically that the distribution function depends on the physical quantities and derivatives,and is independent of the chemical reactions directly as the chemical time scale is longer than the molecular relaxation time.Based on the simulation results of the discrete Boltzmann model,the departure between equilibrium and nonequilibrium distribution functions is obtained and analyzed around the detonation wave.In addition,it has been verified for the first time that the kinetic moments calculated by summations of the discrete distribution functions are close to those calculated by integrals of their original forms. | Xianli Su Chuandong Lin | 2022 | Communications in Theoretical Physics2022，74，3： | 1 |
| 5 | 显示文摘 | Li Han Tang Xinfeng Su Xianli | 2009 | Appl Phys Lett2009，92，20： | 1 |
| 6 | Unsteady detonation with thermodynamic nonequilibrium effect based on the kinetic theory显示文摘In this paper,unsteady detonation is simulated and investigated from the viewpoint of kinetic theory.The deviations of the velocity distribution function from the equilibrium state are studied in the evolution of detonation.It has been discovered that the characteristics of the deviation around the detonation wave are significantly different from those in the post-wave region.Besides,the kinetic moments of the reaction term have been simulated,verified and analyzed in detail.In addition,the reaction manifestation is defined to describe the global effects of kinetic moments due to chemical reactions.It is interesting to find that there are three types of periodic oscillations of the reaction manifestation during the evolution of the unsteady detonation.Via the fast Fourier transform,it can be seen that the reaction manifestation is mainly composed of several signal frequencies.Moreover,the impact of rate constants of the two-step reaction scheme on the reaction manifestation is studied,and the influence of chemical heat is investigated as well. | Xianli Su Chuandong Lin | 2023 | Communications in Theoretical Physics2023，75，7： | 0 |
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