钨金属化与氧化铝陶瓷高温共烧

阐述了钨金属化与氧化铝陶瓷高温共烧工艺的特点,分析了烧结过程中温度曲线和露点等工艺参数对钨金属化与瓷件结合强度、密封气密性和收缩率的影响。通过反复的试验和烧结机理分析对比,给出了最佳的控制参数。     

An FBG impact location system based on broadband light source and improved TDoA algorithm

When a structure material is damaged by impact events, the reliability and lifetime of the material will be severely affected. So impact location is considered as the prime approach for structural health and damage monitoring. In this study, a novel fiber Bragg grating (FBG) impact location system based on broadband light source is designed, aiming at the shortcoming of existing location systems based on FBG. An improved localization algorithm based on the time difference of arrival (TDoA) is proposed for impact location. According to this algorithm, the impact position can be accurately predicted without wave velocity. Impact planar location experiments are carried out for verification of the FBG impact location system and algorithm on a400 mm×400 mm×3 mm aluminum alloy plate. The resulted locating error shows high precision and good stability of the proposed system. This work has been supported by the National Natural Science Foundation of China (Nos.61503218, 61403233, 61573226 and 61473176), the Excellent Young and Middle-Aged Scientist Award Grant of Shandong Province of China (No.BS2013DX018), and the Natural Science Foundation of Shandong Province for Outstanding Young Talents (No.ZR2015JL021). E-mail:pangdan@163.com      

基于单摄像机和神经网络的三维测量研究

为了实现更为简单的三维测量同时解决传统立体视觉方法中基线的限制问题,提出一种单摄像机微小角度旋转结合神经网络进行三维测量的方法.方法通过单摄像机小角度旋转采集二维图像数据;利用电动平台移动标定板构建三维空间坐标系;基于摄像机的线性成像模型思想,将代表图像坐标和三维坐标映射关系的投影矩阵替换为BP神经网络,得到二维坐标到...     

Eavesdropping the display image from conducted emission on network cable of a PC

The display image of a PC can be reconstructed by using the conducted emission on the PC＇s network cable. The relevant signals which be used to reconstruct the original image are coupling from the radiation of the switching of red, green, blue （RGB） signals in PC. These pertinent signals are partly contained in the frequency region higher than 30 MHz in the conducted emission. From these findings, the near-field coupling principle from PC to the network cable is analyzed firstly. And then, a multi-conductor transmission model for the RGB signals which transmit in the network cable is proposed. In addition, the maximum safe distance is estimated by using this model. In order to check the validity of the estimating distance, the eavesdropping experiment is carried out to reconstruct the original display image. The results demonstrate that the blurred display image can be retrieved at the place of 29.5 m.     

平面左手结构色散与传播特性分析

采用时域有限差分方法研究了一种新型平面结构阵列在左手频带内的后向波传播特性与负折射特性,提出分析二维平面左手结构的新方法:基于单元结构的四端口网络参数进行Bloch分析,得出色散关系和Bloch阻抗;根据色散关系和Bloch阻抗分析相位与能量传播方向的关系,以确定出左右手特性频带.相比于以往单元结构分析方法,本文方法利于单元结构的灵活设计,能较好地考虑分布参数元件色散特性,能简便准确地判断出左右手特性频带,且能用于分析各向异性和有损耗结构.仿真分析结果验证了方法的有效性.     

二维缩控生成器的构造与分析

论文基于三元伪随机序列,将钟控生成器和缩减生成器结合进行二维输出,构成一种新型伪随机序列生成器—二维缩控生成器,由其生成的二维缩控序列具有大周期和高线性复杂度,能够抵抗诸如B-M算法等综合算法攻击,且证明了序列游程长度为1或2,数据率为8/9,符号分布基本平衡等性质。因此,二维缩控生成器适合在流密码系统中应用。     

基于Proteus的气压报警系统设计

利用Proteus设计了一种数字气压报警系统。通过MPX4115气压传感器获得与大气压相对应的模拟电压值,经过V/F转换器将模拟电信号转换为数字脉冲信号输入到单片机,单片机接收脉冲信号,经计算处理得出实际的气压值,最后通过数码管显示电路显示出来,并在Proteus上成功完成了仿真调试。结果表明本系统具有携带方便,操作简单,精确度高,适合远距离传送,并可根据具体情况设置警戒值进行智能监测报警,可实现不同环境下的分布-集中监控的特点。     

综合利用稻壳制备木糖、电容炭与硅酸钙晶须

利用酸水解稻壳中的半纤维素制备木糖, 并将糖渣经过炭化后分离出碳和硅, 碳采用稀碱溶液活化改性制备电容炭, 硅采用水热法合成了硅酸钙晶须, 从而使稻壳所有组分得到充分利用. 采用循环伏安(CV)和恒流充放电(GCD)研究了电容炭的电化学性能. 通过X射线衍射(XRD)和扫描电子显微镜(SEM)对所得硅酸钙晶须的结构和形貌进行了表征. 实验结果表明, 稻壳酸水解的最优条件为硫酸浓度7%(质量分数)、 固液比(g/mL)为1:8、 反应时间为2.0 h, 在该条件下, 一次水解、 二次水解和三次水解的木糖收率(Y₁/Y₂/Y₃)和浓度(质量分数, C₁/C₂/C₃)都能达到最大值, Y₁=98.5%, C₁=3.6%; Y₂=85.4%, C₂=6.3%; Y₃=76.6%, C₃=9.0%. 采用15 mL 8%(质量分数) NaOH稀碱溶液活化改性制得的电容炭(AC/15)比电容值为77.32 F/g, 而且具有较好的倍率性和循环稳定性; 硅酸钙晶须为扫帚状针钠钙石晶须.     

两次液液萃取-气相色谱-质谱联用法测定动物肝脏中左旋咪唑残留

建立了液液萃取-气相色谱-质谱联用法测定动物组织中残留左旋咪唑的方法。在碱性溶液中将左旋咪唑盐酸盐转化为左旋咪唑,以乙酸乙酯进行提取;分别以HCl水溶液、氢氧化钾-二氯甲烷体系进行两次液液萃取净化,依次消除提取液中的脂溶性杂质和水溶性杂质,最后进入气相色谱-质谱系统,在选择离子监测模式下,以m/z 148、176、204为定性离子,m/z 204为定量离子进行结构确证和定量检测。结果表明: 左旋咪唑含量在0.25～3.0 mg/L范围内方法的线性关系良好(相关系数为0.999);定量限为5 μg/kg,低于当前国际最低限量标准;在鸡肝、鸭肝、兔肝和猪肝样品中的加标回收率在76%～106%范围内,相对标准偏差(RSD)小于9%。该法简便、稳定性好,无需对样品进行复杂的预处理即可实现对动物肝脏中左旋咪唑残留的快速准确测定。     

速效胃宁冲剂中铝含量分析

用分光光度法测定了五批速效胃宁冲剂中铝的含量。结果表明,用该法测定药物中的铝含量,线性范围0.008～0.200 mg*L-1。五批速效胃宁冲剂中铝含量较丰富,这为临床合理用药提供了有用数据。