杂交元本征应力模式和应力子空间的性质研究

详细讨论了有限元本征应力模式和应力子空间的性质，并着重讨论和进一步完善了与杂交应力有限元应力子空间有关的一些定理，为提出新方法提供了理论基础，主要包括：（1）证明了杂交元特征值不大于对应位移元的特征值；（2）证明了矩阵H非奇异的充分必要条件是假设应力模式线性无关；（3）证明了杂交元所对应位移元的本征应力模式形成的杂交元与该位移元相同；（4）证明了等价假设应力模式形成相同的杂交元；（5）证明了确定杂交元本征应力模式的充分必要条件是其范数平方等于所形成杂交元的变形模态特征值；（6）证明了杂交元假设应力模式与变形模态的能量一一对应的充分必要条件是假设应力模式彼此正交且与所对应位移元的本征应力模式除了一一对应者之外都正交。     

采用压电和粘弹性材料的杂交控制的研究进展

杂交阻尼控制技术是许多工程结构减振和改善性能的重要方法之一.本文主要从杂交阻尼结构的几个特征方面:阻尼结构形式、建模假设、黏弹性材料建模、响应分析方法、控制方法、参数研究和结构选择来研究杂交阻尼结构的研究进展和主要研究成果.研究发现绝大多数的文献只局限于研究梁板的问题.因此很有必要加强对壳体等复杂结构的研究.最后文中指出了有关杂交阻尼结构继续发展的有待深入研究的几个方面.图0参72     

Generalized Forchheimer Equation for Two-Phase Flow Based on Hybrid Mixture Theory

In this paper, we derive a Forchheimer-type equation for two-phase flow through an isotropic porous medium using hybrid mixture theory. Hybrid mixture theory consists of classical mixture theory applied to a multiphase system with volume averaged equations. It applies to media in which the characteristic length of each phase is small relative to the extent of the mixture. The derivation of a Forchheimer equation for single phase flow has been obtained elsewhere. These results are extended to include multiphase swelling materials which have nonnegligible interfacial thermodynamic properties.     

FV/MC混合算法求解轴对称钝体后湍流流场

介绍一种有限容积／Monte Carlo结合求解湍流流场的相容的混合算法．有限容积法求解Reynolds平均的动量方程和能量方程，Monte Carlo方法求解模化的脉动速度—频率—标量联合的PDF方程．将该算法发展到无结构网格，探讨了在无结构网格中实现两种方法的耦合，包括颗粒定位，颗粒场和平均场之间数据交换等问题．并以二维轴对称钝体后湍流流场作为算例，比较了计算结果与实验结果．     

超声速燃烧火焰稳定凹腔质量交换特性的数值研究

对超声速冷流条件下用于超燃冲压发动机的凹腔火焰稳定器的质量交换特性进行研 究. 采用混合RANS/LES方法对非定常流场进行数值模拟，考虑了凹腔的长深比和后缘角度两 个关键参数. 计算得到了凹腔剪切层拟序结构的演化过程. 对凹腔压力振荡历程进行幅频分 析，所得到的频率和理论分析结果及一些计算结果十分吻合. 结果表明，凹腔的长深比和后 缘倾角对凹腔质量交换过程都有较大的影响. 凹腔驻留时间随着长深比的增加而增加. 随着 后缘倾角减小，长深比较小的凹腔的驻留时间增加，长深比较大的凹腔则完全相反. 该计算 结果为凹腔设计提供了新认识.     

Hybrid Dispersion Dirac Semimetal and Hybrid Weyl Phases in Luttinger Semimetals: A Dynamical Approach

It is shown that hybrid Dirac and Weyl semimetals can be realized in a 3D Luttinger semimetal with quadratic band touching (QBT). This is illustrated using a periodic kicking scheme. In particular, the focus is on a momentum-dependent driving (nonuniform driving) and the realization of various hybrid Dirac and Weyl semimetals is demonstrated. A unique hybrid dispersion Dirac semimetal with two nodes is identified, where one of the nodes is linear while the other is dispersed quadratically. Next, it is shown that by tilting QBT via periodic driving and in the presence of an external magnetic field, one can realize various single/double hybrid Weyl semimetals depending on the strength of external field. Finally, it is noted that in principle, phases that are found in this work can also be realized by employing the appropriate electronic interactions.     

Similarity of hybrid numbers

The set of hybrid numbers $𝕂$ is a noncommutative number system that unified and generalized the complex, dual, and double (hyperbolic) numbers with the relation ih =− hi =ε+ i. Two hybrid numbers p and q are said to be similar if there exist a nonlightlike hybrid number x satisfying the equality x ⁻¹ qx = p . And, it is denoted by p ∼ q . In this paper, we study the concept of similarity for hybrid numbers by solving the linear equations px = xq and qx − xp = c for $\text{◂,▸}\mathbf{p},\mathbf{q},\mathbf{c}\in 𝕂\mathbf{.}$     

羟基对界面水分子的扰动与其对非离子型氢氟烃杂化表面活性剂聚集行为的改变

本文合成并比较了具有和不具有羟基的两种非离子型氢氟烃杂化表面活性剂，它们均表现出良好的热稳定性和优异的表面活性. 实验观察到羟基对改变其溶液的表面张力和所形成胶束的形态具有较大的影响. 该作用可归因于烷烃基团从空气/水表面上方到其下方的重排以及由羟基诱导的界面水结构的扰动. 本工作提供了一种通过修改界面处的取向结构来弱化碳氢链和碳氟链之间的不混溶性，从而利于设计具有不同界面性质表面活性剂的策略.     

A cost‐effective curvature calculation approach for interfacial flows on unstructured meshes

We present a simple and cost‐effective curvature calculation approach for simulations of interfacial flows on structured and unstructured grids. The interface is defined using volume fractions, and the interface curvature is obtained as a function of the gradients of volume fractions. The gradient computation is based on a recently proposed gradient recovery method that mimicks the least squares approach without the need to solve a system of equations and is quite easy to implement on arbitrary polygonal meshes. The resulting interface curvature is used in a continuum surface force formulation within the framework of a well‐balanced finite‐volume algorithm to simulate multiphase flows dominated by surface tension. We show that the proposed curvature calculation is at least as accurate as some of the existing approaches on unstructured meshes while being straightforward to implement on any mesh topology. Numerical investigations also show that spurious currents in stationary problems that are dependent on the curvature calculation methodology are also acceptably low using the proposed approach. Studies on capillary waves and rising bubbles in viscous flows lend credence to the ability of the proposed method as an inexpensive, robust, and reasonably accurate approach for curvature calculation and numerical simulation of multiphase flows.     

Effect of the End Groups and the Solvent on the Gelation of the Hybrid Materials from Poly (Vinyl Chloride) (PVC) and Oligo Phenylene Vinylene (OPV)

Abstract

The role of the end-groups of three oligophenylene vinylene (OPV) and the solvents on the hybrid materials from poly (vinyl chloride) (PVC) and the OPV are examined. The gelation of the three organogel OPVs and of the hybrid materials in bromobenzene and benzyl alcohol was characterized. The morphology, as well as the thermodynamic properties, of these OPV and hybrid materials showed that they depended mostly on the solvent and very little on the different end-groups located on the OPV backbones.