一种基于电话网的多功能密码锁的研制

文章介绍了一种采用无线通信、24C01A、ISD1420、单片机和电话网组成的多功能密码锁的电路设计。阐述了该系统的工作原理、硬件构成与程序设计思想。提供了系统框图和程序流程图。     

弹性细杆平衡的动态稳定性

从动力学观点讨论弹性细杆的平衡稳定性问题.建立了弹性杆的动力学方程，导出了杆的弯扭度与截面角速度之间的运动学关系式.对具有弧坐标s和时间t双重自变量的离散动力系统扩充了Lyapunov 稳定性定义.以具有初扭率的非圆截面直杆的平衡稳定性为例，应用一次近似方法证明了当静力学意义下的稳定性条件得到满足时，动力学意义下的稳定性条件必同时满足. 关键词： 弹性杆动力学方程 Kirchhoff理论 Lyapunov稳定性     

LD 泵浦腔内和频连续500. 8nm Nd∶YAG/ LBO 激光器

讨论和分析了Nd∶YAG激光器实现腔内和频及双波长运转的条件,利用激光二极管端 面泵浦Nd∶YAG 的方式,得到1064nm 和946nm 连续双波长运转,并利用Ⅰ类相位匹配晶体LBO ,实现了1064nm 和946nm 激光的腔内和频,获得了连续500. 8nm 的青色激光输出.     

视频编码服务器的热设计

主要阐述了视频编码服务器热设计的原则和实际工作方法,在满足系统性能稳定可靠的前提下,提出含有小型微处理器CPU的嵌入式系统的热设计方案优化目标方向。从热设计基本原理出发,对视频服务器进行了科学的、经济的、实用的热设计。即借助热分析软件,达到了产品设计的高效率。并对微处理器CPU与散热器、印制电子线路板与微处理器CPU的安装工艺方面作了简要的阐述。结果证明:这些措施明显地解决了当今流行的嵌入式系统工作环境受限于应用环境的矛盾,使视频编码服务器的应用范围场合得以进一步延伸和扩展。本身的系统运行也更加稳定可靠。     

LD-pumped passively Q-switched red laser at 660 nm

A laser diode (LD) pumped Nd:YAG red pulse laser at 660 nm was presented by V:YAG passively Qswitching and LBO intracavity frequency doubling. With 1.6-W incident pump power, average output power of 46-mW, pulse duration (FWHM) of 23.3 ns, pulse repetition rate of 21.6 kHz, peak power of 91.4 W, and single pulse energy of 2.13μJ were obtained. The beam quality factor M2 was less than 1.2. The fluctuations of pulse energy and repetition rate were less than 3% in 4 hours. The pulsed laser at 660 nm is expected to be used as the pump source of Cr3+:doped crystal to obtain the gain-switched tunable laser.     

MOOSE模型中的t Hooft反常相消条件

本文讨论了H.Georgi提出的"MOOSE"复合理论中的一个问题,证明了在R_i/j≈0区域的禁闭相理论分析中t Hooft反常相消条件的必要性.     

基于改进MASK R-CNN的舰船目标三维识别

针对二维图像无法表征舰船深度信息、舰船紧密排列识别出现误检等问题,改进了MASK R-CNN的模型方法。首先在目标区域方框和类别预测的基础上,合理重建出三维模型;其次在原始的RPN网络中选取级联的方法增加滑动窗口数量,改善感受野获取信息有限问题;同时增加掩膜分支,在描述舰船目标特征的同时,增加对其轮廓边缘的限制;最后结合非极大值抑制的方法对冗余框进行过滤去除,实现对三维舰船实景目标的识别。进行了仿真实验,对舰船目标识别任务上的性能进行了全面分析,实验结果表明改进后的MASK R-CNN算法相比原始方法,在目标识别准确率上提高了14.8%,证明该方法对三维实景模型目标识别的优越性与准确性。     

WB-KNN for emotion recognition from physiological signals

K-nearest neighbor (KNN) has yielded excellent performance in physiological signals based on emotion recognition. But there are still some issues:the majority vote only by the nearest neighbors is too simple to deal with complex (like skewed) class distribution; features with the same contribution to the similarity will degrade the classification accuracy; samples in boundaries between classes are easily misclassified when k is larger. Therefore, we propose an improved KNN algorithm called WB-KNN, which takes into account the weight (both features and classification) and boundaries between classes. Firstly, a novel weighting method based on the distance and farthest neighbors named WDF is proposed to weight the classification, which improves the voting accuracy by making the nearer neighbors contribute more to the classification and using the farthest neighbors to reduce the weight of non-target class. Secondly, feature weight is introduced into the distance formula, so that the significant features contribute more to the similarity than noisy or irrelevant features. Thirdly, a voting classifier is adopted in order to overcome the weakness of KNN in boundaries between classes by combining different classifiers. Results of WB-KNN algorithm are encouraging compared with the traditional KNN and other classification algorithms on the physiological dataset with a skewed class distribution. Classification accuracy for 29 participants achieves 94.219 2% for the recognition of four emotions.     

基于石墨烯的太赫兹透明吸波器设计

透明太赫兹吸波器既可在太赫兹波段实现吸波功能,又对可见光透明,隐蔽性高,因此其在电磁隐形等领域具有广泛应用。文中设计了一种基于石墨烯的太赫兹双频吸波器,它由方形加枝节的石墨烯上层宽带吸波结构和石墨烯-ITO 嵌套形下层窄带吸收结构构成,实现了独立可调的双频吸波功能。经仿真调试,该吸波器能够通过改变石墨烯费米能,分别在1.98~3.64 THz 范围内调节实现90%以上宽频带吸收率和在4.6~4.9 THz 范围内调节实现96%以上吸收率。经验证,该吸波器具有极化不敏感、宽入射范围等优点。