Reliable tool replacement policy for quality and cost

A tool management model is developed which determines the optimal initial tool setting and tool replacement time in consideration of balancing quality loss, replacement cost, and possible tool failure. A quadratic loss function is employed to characterize the costs resulting from the deviation of part dimension from its target value. The tool reliability function is used to represent the probability of possible tool failure. The model development does not attempt to explain the underlying physics of tool wear and tool failure and does not intend to apply to on-line tool replacement decision. Instead, the present study provides a decision model for management engineers in off-line tool management applications.     

Studies on NaXe Clusters

In this paper all NaCl crystal samples containing metallic sodium colloids used in experiments were cleaved to ~1mm thickness from a block of NaCl single crystal at room temperature1,2. Two parallel large surfaces of each crystal were polished. Then these NaCl crystal specimens were implanted at 10-6 Torr with xenon ions using an accelerating voltage of 36 keV. The xenon ion fluences were in the range from 1(1015/cm2 to 7(1017/cm2. The chemical shifts of 23Na in these NaCl crystal specime…     

Šilnikov manifolds in coupled nonlinear Schrödinger equations

We consider two coupled nonlinear Schrödinger equations with even, periodic boundary conditions, that are damped and quasiperiodically forced. We prove the existence of invariant manifolds with Šilnikov-type dynamics that are homoclinic to a spatially independent invariant torus. Such manifolds appear to induce complex behavior in numerical experiments.     

面向民航需求的通信工程专业建设综合改革

结合现代民航空管领域对通信工程专业人才需求的特点,设计了具有行业特色的专业综合改革建设方案,包括师资队伍建设、课程与教学资源建设、人才培养模式改革,教学方式与方法改革以及教学管理改革等方面,给出了主干课程体系图,为加强工程教育、突出专业特色,更好地为行业服务奠定了基础.     

插层化合物LixTiS2中Li离子-空位二维有序结构稳定性的第一性原理研究

根据局域密度近似下的密度泛函理论，用第一性原理方法对TiS₂，LiTiS₂和Li_xTiS₂(x=1/4, 1/3, 1/2, 2/3, 3/4)有序系统进行了几何优化和总能量计算.将计算结果与已有的实验和理论结果进行了对比，得到的归一化结构参量增量Δa₀和Δc₀随离子浓度单调地增加，与实验结果符合较好.Li_{关键词： x}TiS₂')" href="#">Li_xTiS₂ 有序结构 第一性原理计算 密度泛函理论     

Relations between compositional modulation and atomic ordering degree in thin films of ternary III—V semiconductor alloys

This paper derives the expressions for the ordering degree and the modulation factor of A and B atoms in A_xB_1-xC epilayers of ternary III--V semiconductor alloys. Using these expressions, it identifies quantitatively the alternating atom-enhanced planes, compositional modulations, atomic ordering degree on the group-III sublattices and the fine structure of NMR spectra.     

Buckling of imperfect functionally graded cylindrical shells under axial compression

Buckling behaviors of axially compressed functionally graded cylindrical shells with geometrical imperfections are investigated in this paper using Donnell shell theory and the nonlinear strain-displacement relations of large deformation. The analysis is based on the nonlinear prebuckling consistent theory. Both the prebuckling effects and the temperature-dependent material properties are taken into account. The buckling condition for imperfect functionally graded cylindrical shells is obtained by using the Galerkin method. Numerical results show various effects of imperfection, structural type, power law exponent, temperature and dimensional parameters on buckling. The present theoretical results are verified by those in literature.     

Embedded random matrix ensembles for complexity and chaos in finite interacting particle systems

Universal properties of simple quantum systems whose classical counter parts are chaotic, are modeled by the classical random matrix ensembles and their interpolations/deformations. However for finite interacting many-particle systems such as atoms, molecules, nuclei and mesoscopic systems (atomic clusters, helium droplets, quantum dots, etc.) for wider range of phenomena, it is essential to include information such as particle number, number of single-particle orbits, lower particle rank of the interaction, etc. These considerations led to resurgence of interest in investigating in detail the so-called embedded random matrix ensembles and their various deformed versions. Besides giving a overview of the basic results of embedded ensembles for the smoothed state densities and transition matrix elements, recent progress in investigating these ensembles with various deformations, for deriving a statistical mechanics (with relationships between quantum chaos, thermalization, phase transitions and Fock space localization, etc.) for isolated finite systems with few particles is briefly discussed. These results constitute new progress in deriving a basis for statistical spectroscopy (introduced and applied in nuclear structure physics and more recently in atomic physics) and its domains of applicability.