Polarity control of GaN epilayers grown on ZnO templates

We report the successful growth of Ga-polar GaN epilayers on O-polar ZnO templates pre-deposited on c-sapphire. Prior to GaN growth, NH₃ is exposed onto the ZnO template. The polarity of the GaN layers is confirmed by etching of the surface and by conversion beam electron diffraction (CBED), while the O-polar ZnO is confirmed by CBED. It is suggested that the NH₃ pre-exposure helps form a Zn₃N₂ layer, which possesses inversion symmetry and inverts the crystal from anion polar to cation polar.     

Pedestrian detection and tracking in infrared imagery using shape and appearance

In this paper, we present an approach toward pedestrian detection and tracking from infrared imagery using joint shape and appearance cues. A layered representation is first introduced and a generalized expectation-maximization (EM) algorithm is developed to separate infrared images into background (still) and foreground (moving) layers regardless of camera panning. In the two-pass scheme of detecting pedestrians from the foreground layer: shape cue is first used to eliminate non-pedestrian moving objects and then appearance cue helps to locate the exact position of pedestrians. Templates with varying sizes are sequentially applied to detect pedestrians at multiple scales to accommodate different camera distances. To facilitate the task of pedestrian tracking, we formulate the problem of shot segmentation and present a graph matching-based tracking algorithm that jointly exploits the shape, appearance and distance information. Experimental results with both OSU Infrared Image Database and WVU Infrared Video Database are reported to demonstrate the accuracy and robustness of our algorithm.     

可交联树脂19E的开发及应用

分析可交联树脂１９Ｅ的产品设计及操作设计，并就产品性能与国内餐同类产品进行了对比，进而指出，１９Ｅ适宜于生产３５ＫＶ以下可交联电缆料。     

典型平差方法的比较研究

通过对几种典型平差方法的计算过程、算法效率、算法精度进行对比研究,表明：条件平差方法是既简单又高效的平差方法;4种平差方法的区别主要在于所选未知数的多少,参数直接决定所采用的函数模型;4种平差方法所选择的参数不同,平差精度接近,均在±2.0 mm左右.     

JB/T 4730-2005与SY/T 4109-2005标准射线部分的主要区别

比较了JB／T 4730-2005《承压设备无损检测》和SY／T 4109-2005《石油天然气钢质管道无损检测》两个标准射线部分的不同之处，包括射线源和能量的选择、透照次数、底片质量和质量分级等方面，便于无损检测工作者更好地理解标准和准确地使用标准，从而保证无损检测工作质量和工程焊接质量。     

襄屯灌区泵站的建设与运行

泵站对襄屯灌区工程建设和提水运用至关重要,针对灌溉要求、地质条件、地域环境的不同,采取因地制宜,科学论证来选择泵站实施方案,是搞好泵站工程的关键。文中通过对襄屯灌区已建成4个万亩以上泵站从建设和运行实施上进行总结,从而为以后选取类似最佳泵站方案提供参考。     

基于数据挖掘的高职《C语言程序设计》课程能力培养分析

本文利用了数据挖掘技术对高职院校《C语言程序设计》这门课的考试成绩进行分类和预测,通过有效的挖掘,运用类比较方法．找出学生在学习这门课程中的隐含信息,为提高教学质量和深化教学改革,提供指导和辅助作用。     

黄土丘陵沟壑区退化生态系统恢复的研究

在对黄土丘陵沟壑区现有主要退化生态系统类型进行科学分类的基础上,以时间序列和空间序列相结合,进行植物群落动态变化及其演替规律的观察和研究,结果表明:退耕地植物群落演替趋势是退耕地→草本入侵→灌木入侵→乔木入侵→乔木群落.     

基于小波模极大值极性的行波信号识别

对于行波保护，暂态信号的识别方法是非常关键的，尤其要正确区别正常操作(合闸于空载线路)和线路发生故障等相似的暂态过程。根据行波在波阻抗变化处折反射的规律，利用小波变换模极大值的极性关系可以实现行波信号的快速正确识别。EMPT仿真试验证明了这种方法的有效性和正确性。     

一种新型的三相异步电动机保护电路设计介绍

文章介绍了三相异步电动机电源的相序接反,断相,三相电压不平衡的故障监测保护电路的电路结构及工作原理。