摘要：混合式有载分接开关的切换时序设计对其运行损耗、器件寿命与动作可靠性具有显著影响。本文以非对称星型混合式有载分接开关为研究对象,分析了该分接开关的工作状态与动作过程,构建分接开关切换过程数值仿真模型,进一步研究了非对称拓扑结构与初始相位差对正向与反向切换时序过程中损耗的影响。结果表明反向切换产生的过渡损耗小于正向切换。通过分析机械开关与半导体组件的动作误差及误差对切换过程的影响,合理设置切换动作缓冲区,提升切换可靠性。为了缩短切换过程持续时间、减小过渡电阻损耗,通过建立开关动作容限模型,对动作容错范围进行归一化整合处理,去除冗余开关裕量,对混合式有载分接开关的动作时序进行整体优化,提出具有高容错能力且切换时间更短的动作时序。上述研究对提升混合式有载分接开关动作可靠性与快速切换能力、减小电路损耗提供理论指导。

摘要：针对锚碇基础施工环境及填芯的施工工况进行对比分析,对隔仓模板支撑采用内拉固定和外撑固定两种施工方式进行比选。填芯隔仓高度为7.0 m,内拉固定方式拉杆数量较多,焊接工作量大,需要单独设置隔仓作业平台;采用外撑固定方式,脚手架单层钢管数量多,钢管之间连接扣件数量多、安装拆除工作量大,但既能满足模板支撑需求,又可作为临时施工平台。经有限元软件计算,采用外撑固定工艺模板构件强度、刚度和稳定性满足施工要求,可为类似工程建设提供一定的借鉴。

摘要：Dipole coupled nanomagnets controlled by the static Zeeman field can form various magnetic logic ***, the corner wire interconnect is often unreliable and error-prone at room temperature. In this study, we address this problem by making it into a reliable type with trapezoid-shaped nanomagnets, the shape anisotropy of which helps to offer the robustness. The building method of the proposed corner wire interconnect is discussed,and both its static and dynamic magnetization properties are investigated. Static micromagnetic simulation demonstrates that it can work correctly and reliably. Dynamic response results are reached by imposing an ac microwave field on the proposed corner wire. It is found that strong ferromagnetic resonance absorption appears at a low frequency. With the help of a very small ac field with the peak resonance frequency, the required static Zeeman field to switch the corner wire is significantly decreased by ~21 m T. This novel interconnect would pave the way for the realization of reliable and low power nanomagnetic logic circuits.

摘要：Electron cyclotron resonance heating (ECRH) system is one of the most important Tokamak auxiliary heating methods. However, there are growing demands for ECRH system as the physical experiments progress which meanwhile adds the difficulty of designing and building the control system of its power source. In this paper, the method of designing a control system based on Single Chip Microcomputer (SCM) and Field Programmable Gate Array (FPGA) is introduced according to its main requirements. The experimental results show that the control system in this paper achieves the conversion of different working modes, gets exact timing, and realizes the failure protection in 10us thus can be used in the ECRH system.

摘要：针对调频系统中频率变化快、信号环境高度动态化等挑战,本文提出了一种适用于FPGA(现场可编程门阵列)实现的改进型对角加载SMI(采样矩阵求逆)算法,以增强系统在复杂环境下的抗干扰能力。改进型对角加载SMI算法相较于传统的SMI算法,能够更有效地应对低快拍数和复杂干扰环境下的信号处理需求,且对角加载因子的计算复杂度较低。本文简要介绍了改进型对角加载SMI算法的基本原理以及对角加载因子的计算方法,详细阐述了其在FPGA实现上的改进和性能分析。首先,利用高层综合(Vivado HLS)技术完成了低复杂度的对角加载因子的估计,实现了最优权矢量计算并简化了设计流程。随后,将HLS生成的IP核打包并集成至工程中实现波束合成。仿真结果表明:对角加载SMI算法在FPGA平台上可以达到70 dB以上的信干比改善,表现出显著的干扰抑制效果算法还可在4734个时钟周期内完成抗干扰权值计算与波束合成更新,速度快,能够满足10000跳每秒以上跳频信号抗干扰的实时处理需求。

摘要：液晶光学相控阵被广泛应用于激光雷达、激光通信以及激光武器,进行激光光束的扫描控制。为了实现液晶相控阵的最优设计和激光光束高精度控制,本文重点研究了工作波长、像素数、像素尺寸及有效灰度数对光束指向精度的影响规律。首先,根据液晶相位调制原理,仿真分析了周期光栅法和变周期光栅法的有效扫描角度和衍射效率;然后,基于驱动电压灰度等分相位调制量,仿真分析了指向误差随工作波长、像素数、像素尺寸以及有效灰度数的变化规律,推导出多变量普适公式;接着,仿真分析了驱动电压灰度非等分相位调制量时的指向精度,并和等分相位调制量的结果进行对比分析;最后,实验验证了有效灰度数、像素数和指向误差的关系,初步证实了经验公式的有效性。本文的研究结果可为液晶相控阵的设计提供理论依据。

摘要：在试验验证单电池生热模型准确性的基础上,提出了一种耦合相变材料(PCM)的液冷系统热管理电池模组,采用数值模拟方法定量研究了冷道数量、流速、冷道布置、冷板厚度对电池组最高温度和温度均匀性的影响。结果表明,在4 C放电倍率、35℃时,3条冷道时改变冷却液的流速对电池模组的最高温度和最大温差影响最大,冷却液流速超过0.2 m/s,电池模组散热性能提升不再显著;在冷道数量相同的条件下,冷却液进出口交错分布的电池组间温度和轴向温度均匀性最好;在冷却流速和冷道数量相同的条件下,冷板厚度增大能同时降低电池模组的最高温度和最低温度,在冷道数量为3时,厚度到达8 mm之后对温度的影响不再显著。

摘要：针对苹果采摘机器人的视觉识别算法进行优化,以YOLOv8检测算法为基础进行改进。针对YOLOv8识别算法容易存在漏检错检,同时模型较为复杂,计算参数量较高等问题,设计出一种名为YOLOv8-SNC的目标检测算法。算法引入GSConv替换算法中Neck部分的传统卷积来提升算法整体的轻量化程度,同时在每个检测头前加入CBAM注意力机制提升网络的特征提取能力,使网络更符合苹果采摘机器人的实际需求。实验结果表明,YOLOv8-SNC目标检测算法与YOLOv8相比,精度P提升2.3%,平均精度均值mAP提升1%,浮点运算次数FLOPs减小了9.88%。在面对重果、枝叶遮挡、多目标等复杂环境时,YOLOv8-SNC拥有更好的鲁棒性。YOLOv8-SNC在提升模型检测精度的同时完成模型轻量化,为苹果采摘机器人提供一种高效可行的识别算法。

摘要：为研究钢-超高性能混凝土(UHPC)-普通混凝土(NC)组合梁受弯性能,开展了2根采用不同UHPC-NC界面处理方式的钢-UHPC-NC组合梁和1根对比钢-NC组合梁的受弯试验,研究了试验梁破坏模式、界面滑移、承载能力、变形及应变发展规律。利用有限元程序考虑UHPC-NC界面粘聚力接触关系建立了钢-UHPC-NC组合梁精细化数值模型,分析了UHPC-NC界面配筋率和界面粘结参数对受弯性能的影响。依据试验梁受弯性能与破坏特征,提出了钢-UHPC-NC组合梁UHPC-NC界面抗剪计算分析方法。研究结果表明:弯曲荷载作用下钢-UHPC-NC组合梁各部分协同工作性能良好,最终破坏时展现出显著的塑性弯曲破坏特征,相同截面尺寸下因顶面UHPC层的超高强力学性能,钢-UHPC-NC组合梁的抗弯承载力较钢-NC组合梁更高;UHPC-NC界面采用凿毛糙化和配置充足抗剪钢筋的处理方式能够可靠保证钢-UHPC-NC组合梁的UHPC-NC组合翼板始终协同受力,实现完全组合作用;数值模型计算抗弯性能与试验吻合良好,可用于钢-UHPC-NC组合梁受弯全过程计算分析;采用AASHTO LRFD规范界面参数应用所提UHPC-NC界面抗剪计算方法评估的UHPC-NC界面抗剪结果与试验梁表现基本一致,较为适用于钢-UHPC-NC组合梁UHPC-NC界面抗剪分析。

摘要：The cooling control of the melt during the casting process is of great significance. A comprehensive closed-loop cooling control of castings by adopting a skeletal sand mold design was proposed. The skeletal sand mold consisting of an adaptive shell, functional cavities and a support was designed and created based on the finite difference meshes of a casting. It was applied to a round wall test casting. Two kinds of skeletal sand molds, one with lattice support and the other with enforcing ribs for this casting were designed and printed out by the 3 D printing(3 DP) method. Aluminum alloy A356 was cast by using these two sand molds. The first mold was cooled by natural convection, the other one by water spray cooling. Two sound castings were obtained. The sand mold temperature, cooling curves, microstructures, mechanical properties, residual stress and deformation were measured, compared and discussed. Water spray cooling hastened the cooling rate by 62%, increased the content of Mg and Cu in the α-Al matrix, improved the mechanical properties, and altered the surface residual stress state.