轻小型无人机锂电池在冲击载荷下机械/电化学耦合失效特性试验

为研究轻小型无人机锂电池在受到冲击载荷下的动响应特性及其可能产生的内短路、热失稳以及起火爆炸的规律,开展了轻小型无人机锂电池在落锤冲击下的测试试验,研究了不同落锤跌落能量下撞击载荷、响应模式、电压和温度变化,结合电池的机械响应及其电化学参数变化综合分析了轻小型无人机电池的安全性。研究结果表明：电池单体在受到不同能量落锤撞击后分为三种响应模式：低能量冲击模式、中能量冲击模式、高能量冲击模式;电池冲击载荷以及电池自身的电压变化与冲击能量的变化具有明显的相关性,电池电压和冲击载荷互为影响,具有强关联的耦合特性;电池电量与电池撞击过程中的压降规律、趋势和幅度等电化学性能之间并未有明显的耦合关系,但是对电池受撞击后的着火、爆炸等安全性后果具有重要影响。     

A new method for uniform local heating deep in body using ultrasound phased-array system

A new method for targeted heating of deep tissue was developed by using an ultrasound phased-array system which can generate various multiple foci patterns by electronically changing its amplitude or phase pattern. This method involves using a technique of combining switching and rotating of multiple foci patterns to create a uniform temperature over tissue volumes in various size. Using this method, the target tissue deep in the body can be heated to a specified temperature, which gives conditions for thermo-sensitive liposomes release. A simulation study for a 108-element, spherically sectioned array was performed to determine an optimal heating scheme from a set of multiple focus fields which were produced by inputting different combinations of phases and amplitudes. Comparisons of a static multiple foci field, the switched fields and the switched-rotated fields indicated that the technique of combining switching and rotating of multiple foci patterns has advantages of both lowering the peak temperature and evening the temperature distribution. The simulation results also show that the therapeutic heating zones in various size employing the combined method. These results offer significant data for designing thermotherapy equipment for tumor-specific drug release with thermo-sensitive liposomes.     

含水率对非饱和砂土似黏聚力影响试验研究

目前工程上对待砂土地基时,都是将其作为完全无粘性土来对待,也就是将其粘聚力笼统的作为零。这种方式在理论研究中,简化了很多问题;但是在工程应用中,忽视似粘聚力的存在,有时候会带来诸多的不便,甚至是工程造价的翻番。为了研究非饱和砂土的似粘聚力,本文以工程实例“西咸能源金融大厦的基坑支护项目”为依托,选取了西咸新区,沣河以东,渭河以南交汇区域的砂土,进行了多组不同含水率、相同干密度的砂土的三轴、直剪以及基质吸力试验。试验结果表明：砂土的似粘聚力随着含水率的变化,呈现出由零先急速增长、然后增速放缓、再增速变大增长至峰值,并可以短暂维持峰值阶段,最后逐渐降低为零的结果。同时验证了砂土的直剪试验在工程上的可用性及安全性。其结论可以为非饱和土的研究提供参考。     

Temporal and spatial distribution of tropospheric CO<Subscript>2</Subscript> over China based on satellite observations

Mid-troposphere CO₂ data retrieved by the AIRS (atmospheric infrared sounder) were validated with five ground-based stations and aircraft measurements in the Northern Hemisphere. AIRS CO₂ products show good agreement with ground and aircraft observations. The data had a monthly average accuracy better than 3 ppmv. In this study, the spatial and temporal distribution of mid-troposphere CO₂ from January 2003 to December 2008 was analyzed based on this satellite product. The average concentration of atmospheric CO₂ was higher in the Northern Hemisphere than in the Southern Hemisphere. The yearly average results show a gradual increase from 2003 to 2008. In China, the annual growth rate was about 2 ppmv/a, similar to the United States, Europe, Australia and India, but was slightly lower than Canada and Russia. Mid-troposphere CO₂ concentrations were higher over northern China than over southern areas, due to differences in natural conditions and industrial layout. There were four centers of high CO₂ concentration between 35° and 45°N over China, with low concentrations over Yunnan Province. There was a significant seasonal CO₂ variation with peak concentration in spring and the lowest concentration in autumn.     

以科学发展观统领经济发展方式转变

加快经济发展方式转变,充分反映了科学发展观的内在要求,充分体现了破解经济发展深层次矛盾的迫切需要。这是一场经济社会领域和思想领域的深刻变革,是对党员干部队伍的现实考验。作为老工业基地的太原市要实现科学发展,必须紧紧抓住加快经济发展方式转变的重大战略机遇,进一步凝聚思想共识、突出战略重点、明确重要任务,真正从根本上解决经济社会发展不平衡、不协调、不可持续等深层次问题,推动经济社会又好又快发展。     

弹性时程分析时地震波选用的一种方法

高层建筑用时程分析法分析地震动时,采用不同的地震记录,得到的内力、位移等结果差别很大,与底部剪力法或振型分解反应谱法的结果也有很大出入.地震波的选择又是时程分析法的重要环节,直接影响计算结果的正确与否和结构的安全.由于满足《建筑抗震设计规范》GB 50011-2001(2008)要求的地震波不止一种组合,对于这种情况,提出一种方法来进行最佳组合地震波的选择.     

负电荷磷脂DSPG双层保护的金纳米粒子的合成与表征

采用一步法制备了负电荷磷脂DSPG双层保护的金纳米粒子,并用透射电镜、紫外-可见光谱、X-射线光电子能谱和红外光谱进行了表征.结果表明,所制备的金纳米粒子直径为3～5 nm,具有良好的水溶性和稳定性.     

多元回归分析方法应用实证分析与比较

利用多元统计分析的线性回归分析理论,首先对糖尿病临床采集数据进行相关分析,了解因素之间的相关关系,其次分别采用线性回归的前进法、后退法、逐步回归分析方法,探讨糖尿病病人胰岛素每日注射初始剂量与其影响因素之间的线性关系.根据回归方程调整相关系数、AIC准则等,对比选择最优应用回归模型,确定胰岛素用量及其主要影响因素血糖、尿蛋白的回归模型,对医生临床治疗提供参考.     

基于时变ARVX模型的结构参数识别

详述了线性多自由度结构的ARVX模型实现,通过一个输入输出完整情况下的实例分析,验证了时变ARVX模型用于结构时变参数识别的可行性,并对识别结果进行了分析.     

基于卷积神经网络的移动机器人声源定位方法综述

听觉系统是机器人感知周围环境信息的重要途径之一,精准有效地进行声源定位,可极大提高移动机器人的感知与决策能力。将声源定位应用于危险环境救援与巡检具有重要工程意义。随着深度学习的广泛应用,引入卷积神经网络(convolutional neural networks, CNNs)的声源定位效果显著改善。将移动机器人声源定位研究从网络架构与改进、声音特征类型、数据仿真与增强,以及多模态信息融合四个角度进行综合对比及分析,并对技术的应用提出思考与展望。