Solution for the general integral‐type nonlocal plasticity model with Tikhonov regularization

A new solution approach, based on Tikhonov regularization on the Fredholm integral equations of the first kind, is proposed to find the approximate solutions of the strain softening problems. In this approach, the consistency condition is regularized with the Tikhonov stabilizers along with a regularization parameter, and the internal variable increments are solved from the resulting Euler's equations. It is shown that, as the regularization parameter is increased, the solutions converge to a unique one. A nonlocal yield condition and a nonlocal return mapping algorithm are proposed to carry out the integration of constitutive equations in the time and spatial domains. A global plastic dissipation principle is proposed to relax the classical local plastic dissipation postulate. Numerical examples show that the proposed approach leads to objective, mesh‐independent solutions of the softening‐induced localization problems. A comparison of the results from the proposed approach with those from the gradient‐dependent plasticity model shows that the two models give close solutions.     

Ca对Mg-Gd-Y-Zn-Zr合金热变形行为及热加工性能的影响

利用Gleeble3500热模拟试验机研究了Ca对Mg-Gd-Y-Zn-Zr合金在变形温度573～723 K,应变速率0.001～1 s-1的热变形行为及热加工性能的影响。结果表明:Ca增大了合金的流变应力及变形激活能,扩宽了加工安全区及最佳加工区范围,但降低了最大功率耗散因子及动态再结晶程度。结合激光共聚焦显微镜分析了合金热压缩后组织,验证了热加工图的准确性,并制定了合理的热加工工艺,Mg-Gd-Y-Zn-Zr合金的最佳加工区域为:应变速率0.001～0.01 s~(-1),温度623～723 K。根据最佳加工工艺参数获得了表面质量良好,无变形缺陷的等温锻造合金。     

铸态Mg-8Y-6Gd-1Nd-0.17Zn稀土镁合金高温压缩本构行为及加工图

研究了铸态Mg-8Y-6Gd-1Nd-0.17Zn镁合金在应变量为50%、温度350℃~450℃、应变速率0.0001s-1~0.1s-1的范围内热压缩过程中的本构行为、组织演变和热加工性能。通过选用双曲正弦本构方程来描述合金的流变行为以及变形参数间的关系。实验结果表明，温度和应变速率对Mg-8Y-6Gd-1Nd-0.17Zn镁合金的流变应力行为有重要影响，其流变应力随温度的降低和应变速率的增加而增大，并且在温度高于400℃压缩时，合金的真应力应变曲线具有典型的动态再结晶特性。在本实验条件下，该合金变形期间的活化能（Q）和应力指数（n）分别为359.258 KJ / mol 和5.24，实验值与计算值之间的平均误差（ARE）为3.37％。最后基于动态材料模型加工理论，结合热加工图和压缩过程中的组织演变，确定了该合金的最佳热加工参数为：加热温度400~450℃，应变速率为0.0001s-1~0.001s-1。     

Analyzing dissipation effects on the non-classicality witnessing by a qubit via the entangled state representation

ABSTRACT

In this paper, we study detection of the state non-classicality for a quantum harmonic oscillator by a qubit in the presence of dissipation effects. We show that dissipation can enhance the effectiveness of the method in case of using the corrected form of the related nonclassicality witness. Such an improvement is attributed to the fact that dissipation leads to probing a surface, instead of a curve, of the complex plane for non-classicality condition on normally-ordered characteristic function.     

An image pixel based variational model for histogram equalization

In this paper, we develop an image pixel based histogram equalization model for image contrast enhancement. The approach is to propose a variational model containing an energy functional to adjust the pixel values of an input image directly so that the resulting histogram can be redistributed to be uniform. This idea is different from existing histogram equalization algorithms where a histogram based on the input image is constructed, a mapping is determined to output a uniform histogram and then the pixel values of the input image are adjusted based on the mapping. In the variational model, a mean brightness term is incorporated to preserve the brightness of the input image, and a geometry constraint can also be added to keep the geometry structure of the input image. Theoretically, the existence of the minimizer of the proposed model, and the convergence of the proposed algorithm are given. Experimental results are reported to demonstrate that the performance of the proposed model are competitive with the other testing histogram equalization methods for several testing images.     

New Upper and Lower Eigenvalue Bounds for the Solution of the Continuous Algebraic Riccati Equation

In this paper, applying majorization inequalities, new upper and lower bounds for summation of eigenvalues (including the trace) of the solution of the continuous algebraic Riccati equation are presented. Corresponding numerical examples illustrate that our new bounds extend some of the recent results.     

以南京某工程为例浅谈基坑设计中存在的若干问题

从南京某基坑位移超限出发,探讨了规范中桩身弯矩取值偏低,及坑上局部和锚固段抗弯刚度取值偏高两个问题,这是影响基坑安全和桩顶位移超限的两个重要原因。该文提出了圆截面钢筋混凝土桩抗弯刚度取值的一个方法,与工程实测位移吻合较好。     

基于非线性方程法的齿轮钢淬透性计算模型

采用非线性回归方程计算方法，结合实际生产的齿轮钢淬透性数据对数学模型进行修正。在此基础上，开发了齿轮钢淬透性的计算预报平台，实现根据成分和预设的晶粒度级别预报任意端淬距离的淬透性值。模型预测精度高于传统的多元线性回归方法。     

The influence of process-oriented organisational design on operational performance and innovation: a quantitative analysis in the financial services industry

Market competition requires that organisations excel at both operational performance and innovation. Though process orientation is intended to benefit operations in general, the impact of specific elements remains unclear. The purpose of this study is to identify the specific organisational design components of process orientation that simultaneously influence operational performance and innovation. We survey employees in the financial services sector (N = 1069) regarding the influence of six process-oriented organisation design components on operational performance and innovation using PLS-SEM. The results indicate that organisational structure and process improvement encourage both operational performance and innovation. Personal autonomy is partially beneficial, while the others have no joint influence on operational performance and innovation. This study is first in providing evidence regarding the influence of a broad variety of organisational design components of process orientation on operational performance and innovation. The study contributes to theory on how process orientation improves operational performance and innovation. The findings can serve as a guideline for managers and organisations as to which organisational design components should be implemented to improve operations.     

对弦的横振动方程的修正

以往对弦的横振动方程进行推导时,一般取其近似值,即很小。本文对角不是很小的情形推导出弦的横振动方程,从而更接近于实际。