摘要：A concept of hierarchical stiffened shell is proposed in this study, aiming at reducing the imperfection sen- sitivity without adding additional weight. Hierarchical stiffened shell is composed of major stiffeners and minor stiff- eners, and the minor stiffeners are generally distributed between adjacent major stiffeners. For various types of geo- metric imperfections, e.g., eigenmode-shape imperfections, hierarchical stiffened shell shows significantly low imper- fection sensitivity compared to traditional stiffened shell. Furthermore, a surrogate-based optimization framework is proposed to search for the hierarchical optimum design. Then, two optimum designs based on two different opti- mization objectives （including the critical buckling load and the weighted sum of collapse loads of geometrically imperfect shells with small- and large-amplitude imperfections） are compared and discussed in detail. The illustrative example demonstrates the inherent superiority of hierarchical stiffened shells in resisting imperfections and the effectiveness of the proposed framework. Moreover, the decrease of imperfection sensitivity can finally be converted into a decrease of structural weight, which is particularly important in the development of large-diameter launch vehicles.

摘要：针对含酸性气体、粉尘等恶劣条件下的烟气余热资源回收系统存在的问题,提出了一种适用于恶劣烟气工况下以偏心径向热管为传热元件的余热锅炉,介绍了偏心径向热管技术及其换热器,并对偏心径向热管余热锅炉工艺关键点进行了设计分析,推导出了径向热管安全直径比,对偏心径向热管余热锅炉进行了实际应用研究.结果表明,这种锅炉具有较高的使用性能,余热回收效率达92.5?,使用过程中未发生低温腐蚀现象,系统运行3年未发生影响正常生产的事故,预计换热管使用寿命可达5年.

摘要：模拟训练是现代军事训练的重要且有效的手段，为了提高坦克射击模拟器的视觉真实度，在分析了坦克瞄准镜视场的特点及其变动规律后，建立相应的视景显示数学模型，并根据模型的特殊性，提出一个快速纹理生成算法，该算法在微机平台上可以实时生成地面环境，从而能逼真地模拟坦克行进间射击的动态场面．

摘要：针对复杂障碍环境下的动态目标围捕问题,本文提出一种基于分层强化学习的多无人机协同围捕方法.该方法包含两个层级的学习过程:底层的子策略学习和高层的子策略切换.具体而言,将协同围捕任务分解为导航避障和导航避碰两个子任务,独立学习相应的底层子策略,分别赋予无人机协同围捕目标时所需的避障与避碰技能.在此基础上,设计带有切换惩罚的稀疏回报函数训练高层的子策略切换模块,避免了对人工定义规则的依赖,实现了底层技能的自动组合.数值仿真与软件在环实验结果表明,所提方法能够显著降低围捕策略的学习难度,相较于基线方法具有最高的围捕成功率.

摘要：以江西省萍莲高速莲花隧道为研究对象,分析了全风化页岩地层隧道仰拱开裂的主要原因。针对仰拱开裂区域裂缝的分布情况设计并开展了原位注浆加固试验,通过预埋压力传感器实时监测注浆过程中仰拱受力变化。基于加固后车辆动静载试验过程中荷载的传递特性,提出了一种新的注浆加固效果评价方法。结果表明:隧道底部软弱风化页岩遇水崩解变形是导致仰拱开裂的主要原因;仰拱底部注浆加固时将浆液水灰比从1∶1降低至0.8∶1可提高仰拱基底围岩加固效果,减少浆液流失。注浆加固后开展车辆动静载试验,结果显示荷载传递能力显著提高,表明基底围岩强度、完整性和稳定性显著增强。研究成果可为类似围岩条件下隧道仰拱开裂分析和注浆参数优化提供理论依据和技术支撑。

摘要：本文根据国家、地方和中国海油最新出台的治理挥发性有机污染物(VOCs)排放的标准及要求,结合现有VOCs处理技术,对渤海油田某终端处理厂VOCs治理进行了分析,推荐采用燃烧法中的超低排放燃烧技术进行处理。根据流程设计的基础数据,推荐流程设置为收集装置、输送装置和处理装置,并对每个装置流程进行了介绍,设计处理后的效果能够满足环保排放需求,对我国海上油田陆上终端处理厂的VOCs治理有着重要的意义。

摘要：设计反馈控制器,对一类耦合的vanderPol振子的极限环幅值进行控制.用近似解析方法求出了控制系统的幅值的控制方程,得到了控制参数与极限环幅值的函数关系,使系统的振幅能按需求得到有效地调整.通过数值计算绘制了在不同控制参数下,系统响应的时间历程曲线和极限环.近似解析方法计算得到的结果与数值计算进行了比较,两者是符合的.这一方法也可以推广应用到其他耦合的vanderPol振子.

摘要：超材料因其结构可设计性和优异的物理性能成为近年来的研究热点。热学超材料因能针对性设计红外发射率和反射率等热性能而备受关注。近年来热学超材料朝着"智能化"和"多功能"的趋势发展,智能热调控超材料是实现高效热控的重要途径。以相变涂层为主的传统智能热控材料具有精度低、调控幅度小和可设计性差等局限性。超结构设计能使材料实现理想的电磁特性,并通过表面等离激元等不同的损耗机制实现特定波段的完美吸收。在此基础上,引入相变材料或可重构表面实现的智能热控超材料能够快速、精准地实现热性能的大幅调控。智能热控超材料可实现热场、电场、力场和其他外场等多方式调控。合理的超结构设计能够使材料在热场的被动调控下同时实现吸收率和吸收峰峰位稳定调谐。基于电场调控的材料具有更高的调制精度和快速响应能力。生物启迪的力学热控超材料因其设计简单和柔性的优势而有望大面积应用。此外,基于磁、光等其他外场实现热调控也有相关报道。本文归纳了智能热控超材料的研究现状,首先简单介绍了完美吸收和智能热控的相关概念,从结构设计和损耗机理的角度出发,分析了基于不同外场智能热控超材料的调控途径和研究进展,最后总结了智能热控超材料目前面临的挑战并展望其未来的发展方向。

摘要：对弹簧摆的振动幅值控制进行研究,设计了反馈控制器,对弱非线性系统用近似解析方法求出了控制系统的幅值控制方程,得到了控制参数与幅值的函数关系,使多自由度非线性系统的鞍结分岔得到控制.这项工作可以推广到其他多自由度非线性系统的分岔控制.

摘要：Background:It is not completely clear whether a very high pre-therapy viral load(≥500000 copies/ml)can impair the virological *** aim of this study was to examine the influence of very high baseline HIV-RNA levels on long-term virological responses under one type of ***:A retrospective study was performed based on data from two multicenter cohorts in China from January to November 2009,and from May 2013 to December *** HIV infected adults between 18 and 65 years old were recruited before receiving non-nucleoside reverse transcriptase inhibitor-based *** patients had baseline HIV-RNA levels over 500 copies/ml,good adherence,and were followed for at least 24 *** suppression was defined as the first HIV-RNA<50 copies/*** failure was defined as any of incomplete viral suppression(HIV-RNA≥200 copies/ml without virological suppression within 24 weeks of treatment)and viral rebound(confirmed HIV-RNA level≥50 copies/ml after virological suppression).Chi-square test,Kaplan–Meier analysis,Cox proportional hazards model and Logistic regression were used to compare virological response between each pretreated viral load ***:A total of 758 treatment-naïve HIV patients in China were *** follow-up time(IQR)was 144(108–276)*** week 48,rates of virological suppression in three groups(<100000,100000–500000 and≥500000 copies/ml)were 94.1,85.0,and 63.8%,respectively(P<0.001).Very high baseline HIV viremia over 500000 copies/ml were found to be associated with delayed virological suppression(≥500000 vs<100000,adjusted relative hazard=0.455,95%CI:0.32–0.65;P<0.001)as well as incomplete viral suppression(≥500000 vs<100000,adjusted odds ratio[aOR]=6.084,95%CI:2.761–13.407;P<0.001)and viral rebound(≥50000 vs<100000,aOR=3.671,95%CI:1.009–13.355,P=0.048).Conclusions:Very high levels of pre-treatment HIV-RNA were related with delayed efficacy of NNRTI-based ART and increased risk of treatment failure.