摘要：In this study, two full-size concrete wails were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel （CRE） coating in improving their mechanical behavior under blast loading： one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene （TNT） charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface sWain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests.

摘要：双馈电机变速恒频(VSCF)风力发电系统,是通过调节转子绕组励磁电流的频率、幅值、相位和相序来实现变速恒频控制的.本文在分析双馈电机运行原理和励磁控制方法的基础上,设计和构建了基于80C196MC单片机的VSCF双馈风力发电机的励磁控制试验系统,对变速恒频控制、恒压控制、并网控制以及亚同步速、同步速和超同步速三种不同运行状态之间的动态转换控制技术,进行了试验研究,为MW级变速恒频双馈风力发电机励磁控制系统的设计奠定了基础.

摘要：介绍了直流电机控制电源板的设计方法及具体电路，此电源板具有体积小、结构简单、易于控制等特点，特别是只用四条控制信号线即可实现对晶闸管电路的控制，大大简化了控制电路．实践证明其工作可靠、适用．

摘要：介绍了一种基于西门子S7-200 PLC的路灯节电控制器。该控制器以S7-200 PLC为控制核心,为使路灯可靠运行,实现了路灯节电控制器的自动工作,并根据电网电压、控制器和负载的运行情况,自动选择工作在轻度、中度、深度节电和旁路四种不同的模式。实践证明该节电装置设计合理、节电效果显著。

摘要：介绍一种基于GSM网络的数据传输业务和SMS短消息业务的油田无线防盗报警系统,对其系统结构、工作原理、硬件构成、软件设计等进行了论述。该系统实现了数据的远程通信和井场终端的实时监控。

摘要：直接转矩控制技术(DTC)已广泛应用于感应电动机的调速控制领域,并获得了良好的控制效果.感应电动机的直接转矩控制主要是在工频附近,双馈发电机的直接转矩控制主要工作在低频区域,而直接转距控制技术的低频特性是一个研究热点.对变速恒频双馈风力发电机的直接转矩控制技术进行了理论分析,阐述了它的工作原理和系统结构,推导出有关控制方程,给出了具体的控制框图,并在此基础上利用MATLAB/SIMUlinK进行了仿真研究.仿真结果证明,所设计的控制系统可以实现对输入机械功率曲线的有效跟踪,说明理论分析和提出的控制策略是可行的.

摘要：随着全球气候变化和城市化进程加剧,高密度城市面临洪涝灾害问题日益严重,为定量评估高密度城市洪涝灾害防御能力,提出城市洪涝灾害防御韧性内涵,系统梳理出领导能力、资金能力、抵抗能力、适应能力、管理能力、恢复能力和协同能力七大方面表征城市洪涝灾害防御韧性指标体系,构建基于韧性理论的洪涝灾害防御韧性多指标层次分析评估计算模型,构建7个二级指标和31个三级指标,并以深圳市为例,定量评估城市洪涝灾害防御韧性能力。结果表明:模型可分析出城市洪涝灾害防御韧性水平,准确反映城市应对洪涝灾害防御短板,指导城市提高洪涝防御韧性建设。

摘要：The paraventricular nucleus of the thalamus(PVT),which serves as a hub,receives dense projections from the medial prefrontal cortex(mPFC)and projects to the lateral division of central amygdala(CeL).The infralimbic(IL)cortex plays a crucial role in encoding and recalling fear extinction ***,we found that neurons in the PVT and IL were strongly activated during fear extinction *** PVT neurons inhibited extinction retrieval at recent time point(24 h after extinction),while activating them promoted extinction retrieval at remote time point(7 d after extinction),suggesting a critical role of the PVT in extinction *** the mPFC-PVT circuit,projections from IL rather than prelimbic cortex to the PVT were dominant,and disrupting the IL-PVT projection suppressed extinction ***,the axons of PVT neurons preferentially projected to the *** the PVT-CeL circuit also suppressed extinction ***,our findings reveal a new neural circuit for fear extinction retrieval outside the classical IL-amygdala circuit.

摘要：应用3-D建模软件UG和有限元分析软件ANSYS建立某大型船用减速器斜齿轮多齿啮合的三维有限元非线性接触分析模型。通过接触仿真分析轮齿的变形、综合应力、齿根弯曲应力和齿面接触应力等参数。仿真结果与赫兹理论计算结果相比,说明有限元接触法具有较高的计算精度以及处理复杂边界条件的特点,可为斜齿轮的设计提供可靠的分析手段。

摘要：介绍了Xilinx公司生产的复杂可编程逻辑器件CPLD9572在双馈电机调速装置中的应用及连续调速的控制方法,给出了CPLD(ComplexProgrammableLogicDevice)在此应用中的硬件框图和编程图形.实验结果表明,在系统中应用CPLD可使设计更加灵活、方便、紧凑.