固体发动机保险机构在高温高压下的实验研究

针对固体发动机部件保险机构所出现破现象,对其进行了激光散斑和电阻应变法联合测试。由于保险机构在高温和高压环境下工作,材料有蠕变现象,出现较大的热变形,传统的光我法实施,发展了一种叠合散斑技术,使之能够对大变形进行非接触式测量,在实验室测试的基础上,对保险机构进行了热容器试验,测量了点火后应变随时间的变化规律。实验结构发现,在保险机构机体上存在着一个接近破环应力的高危应力区,这是保险机破坏的主要因素     

解析拟协调平面四边形单元

基于弹性平面问题的多项式解析解，构造出一种新的拟协调平面四边形单元──ＡＱＣＥ单元。算例表明该单元具有计算量小、精度高、便于应用的优点。     

各向异性弹塑性中厚度板壳的有限元分析

本文在文献［２，３］的基础上，提出了一个解各向异性弹塑性中厚度板壳问题的有限元方法。考虑材料各向异性的特点，采用了Ｈｉｌｌ推广的Ｈｕｂｅｒ－Ｍｉｓｅｓ屈服准则；借用Ｏｗｅｎ的剪切修正系数，正确计及了叠层复合材料壳体的横向剪切效应；为了避免“自锁”现象，文中采用了９节点的Ｈｅｔｅｒｏｓｉｓ二次壳单元；特别是本文利用插值外推的思想，提出了一个带预测的弧长增量控制法，显著提高了确定变形路径的计算效率。几个数值算例表明本文给出的有限元方法对于各向异性中厚度板壳的弹塑性分析有较好的精度，尤其是对具有复杂变形路径的结构计算，收敛速度提高更快。     

Large Scale Production of Continuous Hydrogel Fibers with Anisotropic Swelling Behavior by Dynamic‐Crosslinking‐Spinning

Hydrogel microfibers have been considered as a potential biomaterial to spatiotemporally biomimic 1D native tissues such as nerves and muscles which are always assembled hierarchically and have anisotropic response to external stimuli. To produce facile hydrogel microfibers in a mathematical manner, a novel dynamic‐crosslinking‐spinning (DCS) method is demonstrated for direct fabrication of size‐controllable fibers from poly(ethylene glycol diacrylate) oligomer in large scale, without microfluidic template and in a biofriendly environment. The diameter of fibers can be precisely controlled by adjusting the spinning parameters. Anisotropic swelling property is also dependent on inhomogeneous structure generated in spinning process. Comparing with bulk hydrogels, the resulting fibers exhibit superior rapid water adsorption property, which can be attributed to the large surface area/volume ratio of fiber. This novel DCS method is one‐step technology suitable for large‐scale production of anisotropic hydrogel fibers which has a promising application in the area such as biomaterials.

     

Oriented Protein Nanoarrays on Block Copolymer Template

Here, a simple yet robust method is developed to fabricate oriented protein nanoarrays by employing a block copolymer (BCP) template, which presents nano‐scaled spot areas at high‐density arrays. Unlike the conventional BCP nanolithography, the BCP platform described here resists nonspecific protein adsorption and prevents the denaturation of immobilized proteins in aqueous solution. The orderly arranged array areas are functionalized by linking chemistry which allows for the precise control of protein orientation. This approach allows us to generate potentially oriented protein nanoarrays at high‐density array spots, which is useful for miniaturized nanoarrays within high‐throughput proteomic applications.

     

Synthesis,Thermal Properties,and Thermoresponsive Behaviors of Cyclic Poly(2‐(dimethylamino)ethyl Methacrylate)s

This study aims at physicochemical properties of thermo‐ and pH/CO₂‐responsive cyclic homopolymers. Three examples of cyclic poly(2‐(dimethylamino)ethyl methacrylate)s (PDMAs) are synthesized by combining the reversible addition–fragmentation chain transfer process and the Diels–Alder ring‐closure reaction. After cyclization, the glass transition temperature significantly increases (ΔT_g = 51.8–59.7 °C) due to the different configurational entropy and end groups, and the maximum decomposition temperature to lose the pendent groups is drastically decreased from 309 to 278 °C. Effects of polymerization degree, polymer concentration, additive of NaCl, and pH/CO₂ on lower critical solution temperature behaviors of PDMA aqueous solutions are investigated. The cloud points (T_c) of ring PDMAs are usually higher than their linear precursors, and the ΔT_c values obtained under a fixed condition can reach up to 20.7 °C, revealing the crucial role of the topology effect. This study paves the way for unique properties and applications of smart cyclic polymers and their derivatives.

     

Self‐Assembled Colloidal Particle Clusters from In Situ Pickering‐Like Emulsion Polymerization via Single Electron Transfer Mechanism

A simple route is reported to synthesize colloidal particle clusters (CPCs) from self‐assembly of in situ poly(vinylidene fluoride)/poly(styrene‐co‐tert‐butyl acrylate) [PVDF/P(St‐co‐tBA)] Janus particles through one‐pot seeded emulsion single electron transfer radical polymerization. In the in situ Pickering‐like emulsion polymerization, the tBA/St/PVDF feed ratio and polymerization temperature are important for the formation of well‐defined CPCs. When the tBA/St/PVDF feed ratio is 0.75 g/2.5 g/0.5 g and the reaction temperature is 35 °C, relatively uniform raspberry‐like CPCs are obtained. The hydrophobicity of the P(St‐co‐tBA) domains and the affinity of PVDF to the aqueous environment are considered to be the driving force for the self‐assembly of the in situ formed PVDF/P(St‐co‐tBA) Janus particles. The resultant raspberry‐like CPCs with PVDF particles protruding outward may be promising for superhydrophobic smart coatings.

     

New complexity analysis of a full-Newton step feasible interior-point algorithm for $$P_*(\kappa )$$-LCP

In this paper, we consider a full-Newton step feasible interior-point algorithm for \(P_*(\kappa )\)-linear complementarity problem. The perturbed complementarity equation \(xs=\mu e\) is transformed by using a strictly increasing function, i.e., replacing \(xs=\mu e\) by \(\psi (xs)=\psi (\mu e)\) with \(\psi (t)=\sqrt{t}\), and the proposed interior-point algorithm is based on that algebraic equivalent transformation. Furthermore, we establish the currently best known iteration bound for \(P_*(\kappa )\)-linear complementarity problem, namely, \(O((1+4\kappa )\sqrt{n}\log \frac{n}{\varepsilon })\), which almost coincides with the bound derived for linear optimization, except that the iteration bound in the \(P_{*}(\kappa )\)-linear complementarity problem case is multiplied with the factor \((1+4\kappa )\).     

近似周期时间序列分析（英文）

本文首先给出了近似周期时间序列概念,即:具有周期特征但是周期长度变化的时间序列.比如,太阳黑子序列具有11年左右的周期,但是其周期并不是11,而是在11左右变化,这就是一个近似周期序列.然后给出了提取近似周期趋势方法,并且提出了广义差分算子,这里提出的广义差分算子不仅可以消除时间序列的长期趋势和周期性,而且还可以消除近似周期性.最后,以太阳黑子序列为例说明了广义差分算子的应用.     

一类SEI传染病扩散模型及其移动边沿

该文研究一类SEI传染病模型,其中病毒在潜伏期和感染期具有感染性.首先研究固定区域上SEI偏微分方程组,考虑平衡解的局部稳定性和全局稳定性.然后重点研究相应的自由边界问题,其中自由边界表示病毒的移动边沿。给出了该问题解的全局存在性、唯一性,讨论了自由边界的性质,证明了病毒要么蔓延,要么消退.还给出了蔓延和消退的充分条件,结果表明:当有效接触率很小或平均潜伏期较短,且初始染病区域小时,疾病消退;而当有效接触率大或平均潜伏期较长,且初始染病区域大时,疾病蔓延.