一种新的无线电高度表原位检测的高度模拟方法

针对目前对高度表进行原位检测的需求,设计了一种新的高度模拟方法;该方法的实现以ARM为核心,通过高度模拟电路产生各种需要的高度电压信号,从而达到高度模拟的目的,并且无需对机载高度表进行拆装,操作简单、快捷、可靠性较高;实验结果表明,这种方法的高度模拟精度较高,具有一定的实用价值和经济效益.     

Human motion retrieval from hand-drawn sketch

The rapid growth of motion capture data increases the importance of motion retrieval. The majority of the existing motion retrieval approaches are based on a labor-intensive step in which the user browses and selects a desired query motion clip from the large motion clip database. In this work, a novel sketching interface for defining the query is presented. This simple approach allows users to define the required motion by sketching several motion strokes over a drawn character, which requires less effort and extends the users’ expressiveness. To support the real-time interface, a specialized encoding of the motions and the hand-drawn query is required. Here, we introduce a novel hierarchical encoding scheme based on a set of orthonormal spherical harmonic (SH) basis functions, which provides a compact representation, and avoids the CPU/processing intensive stage of temporal alignment used by previous solutions. Experimental results show that the proposed approach can well retrieve the motions, and is capable of retrieve logically and numerically similar motions, which is superior to previous approaches. The user study shows that the proposed system can be a useful tool to input motion query if the users are familiar with it. Finally, an application of generating a 3D animation from a hand-drawn comics strip is demonstrated.     

Effect of an increase in the nitrogen content of the working gas on the microstructure of reactive sputtered TiN thin films

TiN films were deposited on (100)-Si substrates by RF-reactive sputtering. The effects of processing parameters and substrate orientation on the stoichiometry, resistivity and microstructure of reactively sputtered TiN thin films were investigated. The RF-power was fixed at 50 W, and the nitrogen content in the working gas was adjusted so that target nitridation occurred at a relatively low nitrogen content, 2.6% N₂, in a fixed total flow rate of gases of 46.25 standard cubic centimetres (sccm). The N₂ percentage was varied from 2.6% to 15.4%. The films were continuous and 200 nm thick. Films deposited with the substrate facing the target exhibited 111-texturing, while films on substrates lying in the same plane of the target surface had 100-texturing. Both X-rays photoelectron spectroscopy and high-resolution detailed scans of the Auger electron energy spectrum were used for the stoichiometry determination. On the 100-textured TiN films, the N/Ti ratio was 1.0 at low N₂ flow rates; the N/Ti ratio rapidly increased with N₂ flow rate, and then levelled off. The films had resistivities ranging from 85 to 1340 µ cm, and the functional dependence of both N/Ti and the resistivity values behaved similarly with increasing N₂. X-ray single-line profile analysis of the 200-reflection indicated that the average crystallite size decreased and the average strain increased with increasing nitrogen content in the working gas. The Si/TiN structures were heat treated in the temperature range from 300 to 600°C in a quartz tube under 1 atm (10⁵Pa) of flowing high purity Ar gas. Heat treatment at 300°C did not affect the TiN film integrity, while treatment at 400–600°C resulted in void-type defects.     

火炮磁流变后坐系统仿真

将磁流变技术应用于火炮反后坐装置是目前正在发展的一种降低火炮后坐力的新技术,优化火炮反后坐装置控制,达到实时调节阻力。针对某型号火炮,在建立动力学模型和电磁模型的基础上设计了磁流变反后坐系统。为实现理想的后坐控制规律,提出了PID和模糊控制算法。利用ADAMS和MATLAB进行联合仿真,仿真结果表明,在后坐行程范围内,最大后坐阻力分别为3.71×105N,3.53×105N,相比传统火炮减小了13%和17%,并且模糊控制的后坐阻力曲线具有良好的"平台效应",实现了控制目标,表明磁流变阻尼器良好的可控性和应用于火炮后坐系统中的可行性。     

有限遥测速率下卫星遥测数据设计方法研究

针对国内小卫星常用的统一遥测模式,讨论了在遥测速率受限的条件下,分包遥测格式设计应满足的基本条件;定义了分包遥测数据格式设计过程中的包编码损失率,并以此作为包数据格式编码效率的评价函数;分析了分包遥测数据格式设计过程中包长度、包采样周期等参数变化对评价函数的影响,进而给出了分包遥测数据格式设计中的应满足的条件和遵循的原则。     

基于柔直换流阀的交流电压定量调节方法

柔性直流无功分量可选择定交流电压控制和定无功控制,换流站现场常采用定无功功率控制.调度可下令通过柔直发出或吸收无功来调节交流电压到目标值,但调度指令一般是交流电压目标值,需要由换流站通过多次无功遥调指令来实现调压,这不仅增加现场操作风险,也给系统引入多次无功和电压小扰动.本文提出一种"两步调压法",第1步测试当前系统短路容量水平,第2步根据当前系统容量水平精确计算无功量,从而能够实现柔性直流换流阀无功控制对交流电压的定量调节.该方法通过两步调压,即可满足精确调压需求,无需对电网系统容量进行实时计算,简便实用.通过PSCAD/EMTDC离线仿真和基于RTDS的控制保护设备硬件在环仿真测试,验证了本方法的有效性.     

基于9种无约束优化算法的岩爆预测BP模型优选

为研究不同训练样本数量和无约束优化算法对岩爆BP(Back Propagation)神经网络模型预测准确率的影响,选取围岩最大切向应力与岩石单轴抗压强度比σθ/σc、岩石单轴抗压强度与单轴抗拉强度比σc/σt和弹性能量指数Wet作为预测指标,广泛搜集整理100组典型岩爆实例建立了训练样本数据库.在样本数量分别为40、70和100时,基于标准算法和9种无约束优化算法建立了10个岩爆BP神经网络预测模型,并提出了考虑不同样本规模影响的岩爆烈度等级预测指数——综合准确值N.比较研究结果表明:BP模型的预测准确率随样本数量增加而提高,3种样本数量下的模型平均预测准确率分别为62.5％、76.4％和87.5％;基于9种优化算法建立的BP网络模型的N值均高于标准BP模型;基于Ploak-Ribiere共轭梯度法优化的BP模型的N值(195)和预测准确率(99.0％)均最高,且在5个工程实例中的预测结果完全符合现场实际,优于标准BP模型、支持向量机模型和其他优化模型,为岩爆烈度等级预测的最佳模型.     

预应力中空棒构件设计与力学特性

为满足装配式建筑节点接缝混凝土抗震性能的需要,以一种自平衡预应力中空棒为研究对象,研究接缝位置短杆件施加预应力的效果。根据力的平衡机理,对结构内部钢棒施加压力使结构外部钢管协调受力拉伸,达到设计预应力后由螺母锁定,将杆件埋入到装配式节点接缝混凝土,浇筑早强灌浆料,待固结达到预定强度释放反力棒,依靠外螺纹结构与混凝土的粘结力自锚实现接缝混凝土施加预应力。力学性能分析方面,研究杆件张拉阶段、静置松弛阶段应力变化及损失情况,验证了杆件张拉完成至放张前应力存储的有效性,通过分析杆件放张后应力分布、预应力损失等参数,验证了杆件应用到节点混凝土后传递应力的机理及有效性,并采用有限元方法分析预应力混凝土构件应力分布规律。研究结果表明预应力中空棒技术作用于装配式节点接缝混凝土具有较高的抗震和耗能能力,对装配式建筑节点混凝土高抗震性能的实现提供了一种新的技术手段。     

图像背景修正对电缆终端状态监测效果研究

为了实现智能电网管理信息化、智能化的目标,对不同类型的电缆终端工作状态监测方式进行比较与分析.基于可见光、红外热成像、声波检测系统,设计一种基于红外热成像系统为主的电力电缆终端状态检测装置.该装置可由设备本体进行供电,也可外接电源,实现24 h不间断对异常电力电缆进行实时状态检测.实时检测的数据存储于本地系统,利用专业开发的电力电缆终端状态检测软件进行数据查询、数据分析、报表导出,形成闭环系统.采集的数据亦可后台进行二次分析,可提取采集的红外热图中的所有温度点信息,为后期维护提供有效的数据支撑,实现电力电缆终端状态监测的目的.     

光纤传感技术在电力设备监测领域的研究进展

光纤传感技术具有抗电磁干扰、体积小、多路复用等优点,用其进行电力设备智能化在线监测已成为电网发展的新趋势.本文综述了几种光纤传感技术在电力设备监测领域的研究进展,包含光纤光栅传感技术、散射型分布式光纤传感技术、荧光光纤传感技术和干涉型光纤传感技术.从温度监测、应变监测、局部放电监测、光纤电流传感器、污秽监测和氢气监测等几方面阐述了不同传感技术在不同电力设备中的应用情况及优缺点,并展望了光纤传感在线监测技术工程化、组网化应用的发展方向.