Masahiko MORINAGA
,
Yoshinori MURATA
,
Hiroshi YUKAWA
材料科学技术（英文）
A molecular orbital approach to materials design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approach is reviewed. In particular, it is stressed that New PHACOMP approach is useful for predicting the formation of topologically close-packed (TCP) phases (e.g., σ phase and μphase ) in nickel based superalloys. Compared to the current PHACOMP, New PHACOMP provides a better tool for designing those alloys which are free from such TCP precipitates at service temperatures. In addition, the d-electrons concept is shown for alloy design and development.
关键词:
High temperature materials
,
null
,
null
,
null
Physical Review E
The spatial structure of dusty plasma confined in a spherical microcavity has been investigated by use of the density functional theory for classical fluids, in which all particles undergo an isotropic harmonic potential and the interparticle interaction is described by the hard-core Yukawa potential. The fundamental measure theory of Rosenfeld and its modified versions have been used in the energy functional to incorporate hard-core interactions between particles. Based on the variational principle, the equilibrium density profile can be obtained by use of an iteration calculation with the average density of particles as an input. In terms of density profiles presented under various conditions, the roles of the trapped parameter, coupling parameter, screening parameter, and the average number density of particles are discussed, and significant influences of these factors on the structure of confined dusty plasma are found.
关键词:
fundamental-measure-theory;hard-sphere fluid;coulomb-crystal;shell;structure;yukawa balls;particles;clusters
Journal of Physics-Condensed Matter
We present a detailed study of both the topological and the chemical short-range orders for liquid Na-Cd alloys using interatomic potentials derived from a non-local model pseudopotential theory. First, the mixing entropy is predicted using a hard-sphere Yukawa reference system, with the parameters being measured from the pseudopotential-calculated mean interatomic interactions and the ordering potentials. It is found that the ordering contribution to the entropy reaches its largest magnitude at around 30 to 50 at.% (atomic per cent) of Na, while above 70 at.% Na, the contribution is small. Then, the atomic structures are calculated using molecular dynamics simulations combined with an energy mapping technique. From the careful examination of the calculated structural distribution functions, the chemical shea-range-order parameters and the pair analysis results, we found that with increasing Na concentration, the Na-Cd alloy system exhibits a chemical ordering tendency from compound forming to phase separation, and a topological ordering tendency from a Cd-like structure characterized by 1311- and 1422-type atomic bonded pairs to a Na-like one characterized by 1551-type atomic bonded pairs.
关键词:
thermodynamic properties;binary-alloys;ga
费飞
,
熊琰
,
栗晶
,
柳朝晖
,
郑楚光
工程热物理学报
本文利用布朗动力学和斯托克斯动力学方法对胶体在剪切流动下的重构和断裂过程进行了数值模拟,计算并分析了颗粒间作用势以及流体相互作用力对胶体断裂的临界剪切率的影响.模拟中胶体颗粒间作用势采用了L-J势和Yukawa排斥势的组合模型.模拟结果显示,作用势最大值与最小值的差决定了胶体断裂的临界剪切率,但由于胶体的几何构型(也是作用势的函数)的影响,两者的依存关系是非线性的.布朗动力学方法虽然不包含颗粒间的流体相互作用力,但是与斯托克斯动力学方法的结果比较发现,当颗粒间作用势较强,胶体满足刚性假设时,布朗动力学方法依然能够定性地给出胶体在剪切流动下的断裂规律.
关键词:
胶体重构
,
流体相互作用
,
斯托克斯动力学
