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.     

利用废旧泡沫塑料制备涂料

将废旧泡沫塑料加工改性后，使其由非极性物质转变为半极性物质，以其为原料来制备附着力较好，抗水、抗冻、抗酸、抗碱、抗盐等性能的不同颜色的涂料．对当今社会上越来越多的“白色污染”进行了综合利用，为净化环境起到了不可低估的作用．     

母差保护出现的问题及处理过程

本文介绍了220kV金砂变电站Ⅱ期扩建工程投运中220kV母差保护出现的问题及处理过程,指出了继电保护 设计、安装、调试、维护工作的重要性,对每个环节都需要认真处理。     

A simple atomic force microscopy method for the visualization of polar and non-polar parts in thin organic films

Here we present a scanning probe microscopy method that allows for the identification of regions of different polarity (i.e. hydrophilicity) in thin organic films. This technique is based on the analysis of the difference between phase images generated at different applied bias voltages in tapping-mode atomic force microscopy. We show that, without any chemical modification of the microscope tip, it is possible to investigate surface properties of complex macromolecular layers, yielding new insight into the functional properties of the photosynthetic electron transport macromolecular complex, Photosystem I.     

Ranked WordNet graph for Sentiment Polarity Classification in Twitter

This paper presents a novel approach to Sentiment Polarity Classification in Twitter posts, by extracting a vector of weighted nodes from the graph of WordNet. These weights are used in SentiWordNet to compute a final estimation of the polarity. Therefore, the method proposes a non-supervised solution that is domain-independent. The evaluation of a generated corpus of tweets shows that this technique is promising.     

油纸绝缘直流极性反转试验及局部放电测量

对油纸绝缘缺陷模型在极性反转过程中局部放电特征图谱以及空间电荷特性进行了研究,实现了对油纸绝缘极性反转过程中局部放电信号和空间电荷的测量。     

Electro-osmosis treatment techniques and their effect on dewatering of soils,sediments, and sludge: A review

Electro-osmosis is an established method of dewatering fine soils, sediments, and sludge (SSS). The efficiency of electro-osmotic treatment is controlled by the electrical resistance of the system. Due to an increase in SSS resistance during treatment, its cost efficiency is reduced, limiting the widespread use of this technique. The aim of this paper is to discuss the main reasons for the increase in SSS resistance during treatment and then to analyze the most recent and widely spread modifications to classical electro-osmotic treatment that attempt to combat these issues and improve the efficiency of the technique. These modifications to electro-osmotic treatment are polarity reversal, an intermittent current, the injection of chemical solutions at the electrodes, and the use of geo-synthetics. The paper discusses the relevant research on the above adaptations, and the advantages and disadvantages of each are evaluated and compared using the available laboratory and field tests in the literature on electro-osmotic dewatering research. All four methods of modification are shown to provide significant improvements and can be successfully translated to the field for greater use. However, the improvements they bring about may not be sufficient to warrant their general use in geotechnical applications.     

含水汽凝析气体系相态仿真模拟研究

凝析气藏中的水汽对凝析气体系相态变化有影响。在地层中等温降压时,含水汽的烃类体系会发生反凝析现象。在反凝析现象中会产生凝析水和凝析油。这些反凝析液的聚集效应会造成凝析气井的产能严重损失。这就使得控制反凝析液的析出成为提高凝折气藏采收率的关键。在研究中,总结了含水汽凝析气体系的相态特征。同时,在对某含水汽凝析气体系相态实验分析的基础上,对该体系分考虑水汽和不考虑水汽2种情况进行相态仿真模拟。模拟结果大致与实验观测值一致。     

关于耦合谐振滤波器中耦合极性的几点讨论

对改变带有交叉耦合的耦合谐振滤波器中的耦合系数的极性而不改变滤波器的性能 ,本文给出了一个充分条件及其两个推论。这为滤波器的设计和实现带来了一定的灵活性。结合这一充分条件 ,本文还详细解释了滤波器中的耦合极性的相对性问题。最后给出了在确定耦合系数矩阵后实现滤波器时设计耦合结构的一种通用方法。