摘要：With the increasing attention received by lightweight metals,numerous essential fields have increased requirements for mag-nesium(Mg)alloys with good room-temperature and high-temperature mechanical ***,the high-temperature mechanic-al properties of commonly used commercial Mg alloys,such as AZ91D,deteriorate considerably with increasing *** the past several decades,extensive efforts have been devoted to developing heat-resistant Mg *** approaches either inhibit the gen-eration of thermally unstable phases or promote the formation of thermally stable precipitates/phases in matrices through solid solution or precipitation *** this review,numerous studies are systematically introduced and *** alloy systems,includ-ing those based on Mg–Al,Mg–Zn,and Mg–rare earth,are carefully classified and compared to reveal their mechanical properties and strengthening *** emphasis,limitations,and future prospects of these heat-resistant Mg alloys are also pointed out and dis-cussed to develop heat-resistant Mg alloys and broaden their potential application areas in the future.

摘要：The experimental and numerical investigations on electromagnetic control of cylinder wake have been performed in this paper. Experiments were conducted in a rotating annular tank filled with a low-conducting electrolyte. A cylinder with an electromagnetic actuator mounted on the surface was placed into the electrolyte. Force measurements have been carried out by strain gages attached to a fixed beam to which the hydrofoil is suspended and flow fields are visualized by dye markers. Based on the Navier-Stokes equations considering the electromagnetic body force, i.e. Lorentz force, in the ex- ponential-polar coordinates, the numerical investigations were carried out by means of an Alterna- tive-Direction Implicit algorithm and a Fast Fourier Transform algorithm. Experimental results have shown the same tendency with the numerical results. For the constant Lorentz forces, called open-loop control, the vortex shedding was fully suppressed. Meanwhile, the weak street disappeared and the drag force was reduced. Based on the Navier-Stokes equations, an adjoint-based ensemble optimiza- tion of control algorithms was developed and adjoint equations in the exponential-polar coordinates were derived. The equations were solved by numerical algorithm as mentioned above. The evolutions of the flow field in the control process were discussed according to the calculated variable optimal interaction parameters.

摘要：目的 分析不稳定型心绞痛(UAP)患者经皮冠状动脉介入治疗(PCI)后发生冠脉微循环损伤的现状及其影响因素。方法 选取2018年7月至2021年11月商丘市第一人民医院心血管三病区收治的105例UAP患者,均接受PCI治疗。统计患者术后1 d冠脉微循环损伤发生状况,并将其分为发生组与未发生组,由研究者设计临床资料调查表,统计两组临床资料并进行比较,将可能的影响因素纳入,分析导致UAP患者PCI后发生冠脉微循环损伤的相关因素。结果 经PCI治疗后,105例UAP患者中有51例发生冠脉微循环损伤,发生率为48.57%;发生组合并糖尿病占比高于未发生组,预扩张时间长于未发生组,同型半胱氨酸(Hcy)、超敏C反应蛋白(hs-CRP)水平均高于未发生组(P1,P<0.05)。结论 UAP患者PCI后冠脉微循环损伤的发生与合并糖尿病、预计扩张时间长、Hcy水平高、hs-CRP水平高有关。

摘要：为了综合提高正交异性钢桥面板的抗疲劳性能和经济性,以顶板厚度、U肋厚度、横隔板厚度为设计参数,以U肋角焊缝最大拉应力、弧形开孔最大压应力、U肋嵌补段最大拉应力、单位长度用钢量为目标响应,开展了正交异性钢桥面板优化设计研究。基于有限元仿真,确定了不同疲劳易损部位的最不利荷载位置,通过Box-Behnken试验设计方法开展了多参数仿真分析,通过F检验法分析了设计参数对目标响应的影响显著性水平,提出了目标响应简化非线性响应面拟合方程。最后构造了多目标优化期望函数,对目标响应进行了组合优化。结果表明:优化结果相比于原设计值,结构最大应力指标下降27.2%,单位长度用钢量下降18.4%,抗疲劳性能与经济性显著提升。

摘要：针对煤矿井下无GNSS信号、主流激光SLAM算法易出现特征约束不足而导致退化问题,提出了一种面向煤矿井下环境的激光雷达、IMU紧耦合SLAM算法。首先,设计一种动态提取特征点方法,通过检测煤矿井下环境是否发生退化,动态调整特征点提取数量,构建丰富且良好的特征信息约束矩阵,提高位姿估计准确性;然后,利用因子图优化实现煤矿井下稳健精确的SLAM;最后,通过煤矿井下实测数据进行了广泛的试验分析。结果表明:提出的激光SLAM算法表现较好,位姿估计误差在平面方向较LIO_SAM降低了50.93%,在高程方向降低了42.13%,可为煤矿机器人智能感知、安全巡检提供了技术参考。

摘要：C2与试验领域的互联基础设施TENA间的异构性阻碍了两类系统的互操作。报文传输服务包括端-端和跨网部署模式,相应地设计了与TENA系统的两种互联架构。网关的设计方案有单线程和多线程模式;从互操作视角来看,网关实现了通信协议、对象模型和支撑服务间的互操作。针对TENA的"拉"模式通信机制,设计了与C2系统通信时的协调机制;利用OWL建立报文的元模型,通过模型转换实现异构对象模型的互操作;利用自定义的消息代表支撑服务,解决了异构系统间服务的不匹配问题。通过原型试验得到交互实体个数、线程个数与信息交换实时性之间的规律。

摘要：卷到卷(roll-to-roll,R2R)制程普遍应用于柔性材料的量化生产中,其套色精度是产品质量的关键因素。R2R制程是一个多输入多输出、强耦合的复杂生产过程,实现高速高精度套色控制是其基本要求。首先,根据R2R印刷系统的状态空间模型,设计了基于降维观测器的状态反馈控制方法,同时通过粒子群优化算法对状态反馈的极点进行优化,实现了套色误差的高精度控制。将提出的套色控制方法与最新发表的全解耦比例微分(fully decoupled proportional-derivative,FDPD)套色控制方法进行对比,所提方法在套色精度上获得了50%~80%的提升,调节时间缩短了50%~65%,控制量绝对值之和仅为FDPD控制方法的46%~57%,这不仅减少了对执行机构的冲击,也节约了能量。对比结果证实了降维观测器的估值准确性,也表明所提方法能够明显提高控制性能。

摘要：为解决西藏地区配电网防雷困难的问题,开展了重雷区配电网综合防雷的研究。首先分析了当前防雷技术措施存在的问题以及整治方法,设计了一套综合防雷的技术方案。通过选取合适的避雷器、加装雷击计数器以及并联接地体的一系列手段进行防雷,降低配电网雷击故障率。其次,开展试点防雷工作,验证所提方案的有效性,并根据现场应用过程中存在的问题进行了防雷方案的改进,研发了接地开关与跌落式避雷器二合一装置,有效提升了西藏地区配电网防雷性能。

摘要：分析了火箭橇动态试验时振动频率宽、振动强度大的振动特性,建立了基础激励下双层减振模型,通过参数优化设计,设计了火箭橇双层减振系统。通过仿真计算和试验验证,双层减振系统可有效抑制火箭橇动态试验的高频振动,使橇车振动满足常见被试品工作环境要求。

摘要：为实现工程目标与不同背景融合要求,开展针对环境变化的吸波材料定制化设计方法及涂层配方研究。根据传输线理论,通过设置多变量参数,编制了基于衰减量可调的改进遗传算法设计程序,对比实测与模拟值结果,验证了该方法的可行性;在分析电磁参数对吸收峰影响规律基础上,研究提出了采用磁改性填料对反射率曲线定向调节的方法。结果表明,优化的涂层配方实现了在Ka波段的宽频吸收,亦降低了目标与背景的辐射温差对比,满足了涂覆目标在主被、动探测下兼容的要求,可用于工程目标的防雷达伪装。