几种管道补偿器的选择和安装

介绍了几种常用的管道补偿器，如自然补偿器、Ⅱ形补偿器、波纹补偿器和套管式补偿器及其优缺点和选用原则，并就补偿器的安装问题进行了探讨。     

Dynamic oxide voltage relaxation spectroscopy

A new method for trap characterization of oxidized silicon is described. The Dynamic Oxide Voltage Relaxation Spectroscopy (DOVRS) is an improved version of the formerly proposed Oxide Voltage Relaxation Spectroscopy (OVRS) technique which applies a periodic long duration constant current for tunneling injection. It has been demonstrated that the new technique can be used not only to separate and identify the oxide trap from interface trap, but also to separate and determine the centroid from the oxide trap density generated in the MOS system by the tunneling current stress. In the pulse constant current mode, the OVRS measurement can be completed instead of using the double current-voltage technique. Thus the new method results in more accurate and quicker measurements of the oxide trap centroid. Analytical expressions for computing the paramaters of the interface and oxide traps are derived. The effect of the channel carrier mobility on the spectroscopy is also considered. Two types of oxide and two types of interface traps were observed at a pulse constant Fowler-Nordheim current stress by the new method of DOVRS     

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煤层气采出有扩散和渗流两个过程，比常规天然气层中的渗流方程复杂。煤层气由煤层流入井筒的过程为：随着煤层中水的不断采出，地层压力下降，吸附在煤层中的煤层气被解吸出来，并扩散至割理，割理中的气体渗流到达井筒。采用非平衡态吸附模型，研究单相煤层气在煤体和割理中的流动规律。在拟稳态流和不稳态流的数学模型假设下，用气体标准压力代替Ｌａｎｇｍｕｉｒ吸附公式中的压力，得到气层中标准压力所满足的方程。如果考虑无限大地层或有界圆形封闭和定压地层，最终得到井底无量纲准压力及其导数的解。     

基于关键链优化的课程教学与实践教学契合OA绩效方法研究

作为高等教育体系中的两大主要模块,课程教学与实践教学在时间维度、逻辑维度和认知协同维度往往会存在矛盾,导致了教学质量的降低。本文从这三个维度出发,首先确定了具有普适性的教学绩效评估方法;随后根据多项目管理的关键链法提出了教学优化的具体步骤;最后以工商管理专业课程为实例根据上述教学绩效评估方法验证了教学优化的效果。     

负离子分解室内有机化合物的测试

低浓度、高毒性的挥发性有机化合物(VOC)污染大气,造成“病态建筑综合症(SBS)”,严重威胁着人们的身体健康。空气中的负离子除有利于人体生理健康以外,还能有效分解空气中的VOC。将一种负离子添加剂添加到墙体涂料中,可以得到一种能有效释放负离子的涂料。本文测试了涂刷负离子添加剂涂料的测试小室中负离子分解总挥发性有机化合物(TVOC)及甲醛的性能,结果证明:涂料释放的负离子能有效分解VOC,使室内VOC的浓度在较短时间内满足GB/T—18883—2002的要求。     

多相主动轮廓模型的眼底图像杯盘分割

目的 视盘及视杯的检测对于分析眼底图像和视网膜视神经疾病计算机辅助诊断来说十分重要,利用医学眼底图像中视盘和视杯呈现椭圆形状这一特征,提出了椭圆约束下的多相主动轮廓模型,实现视盘视杯的同时精确分割。方法 该算法根据视盘视杯在灰度图像中具有不同的区域亮度,建立多相主动轮廓模型,然后将椭圆形约束内嵌于该模型中。通过对该模型的能量泛函进行求解,得到椭圆参数的演化方程。分割时首先设定两条椭圆形初始曲线,根据演化方程,驱动曲线分别向视盘和视杯方向进行移动。当轮廓线到达视盘、视杯边缘时,曲线停止演化。结果 在不同医学眼底图像中对算法进行验证,对算法抗噪性、不同初始曲线选取等进行了实验,并与多种算法进行了对比。实验结果表明,本文模型能够同时分割出视盘及视杯,与其他模型的分割结果相比,本文算法的分割结果更加准确。结论 本文算法可以精确分割医学眼底图像中的视盘和视杯,该算法不需要预处理,具有较强的鲁棒性和抗噪性。     

瞬态瑞雷波法在建筑场地类型及类别勘察中的应用

瞬态瑞雷波法是一种较新的技术,在工程勘察中有着广泛的应用,在建筑场地勘察中,瞬态瑞雷波法能快速地提供地层的剪切波速度,评价建筑场地类型及类别。本文介绍了几个典型的应用实例,展示了瞬态瑞雷波法典型的原始记录,同时指出在瞬态瑞雷波法应用的优势和不足。     

激光一同轴电弧复合焊接热源焊接

在建立和研究空心钨极电弧的基础上，对激光一同轴电弧复合焊接热源焊接特性进行了深入研究。试验结果表明，激光与电弧相互作用增强的效果十分显著，采用同轴电弧作为辅助热源增大焊接熔深的效力优于激光一旁轴电弧复合焊接热源焊接效果。在试验的基础上，得到了激光一同轴电弧复合焊接热源焊接熔深的变化规律。     

Nonconvex plus quadratic penalized low-rank and sparse decomposition for noisy image alignment针对含噪图像对准问题的非凸加二次罚项约束的低秩和稀疏分解方法

This paper proposes a general method for dealing with the problem of recovering the low-rank structure, in which the data can be deformed by some unknown transformations and corrupted by sparse or nonsparse noises. Nonconvex penalization method is used to remedy the drawbacks of existing convex penalization method and a quadratic penalty is further used to better tackle the nonsparse noises in the data. We exploits the local linear approximation (LLA) method for turning the resulting nonconvex penalization problem into a series of weighted convex penalization problems and these subproblems are efficiently solved via the augmented Lagrange multiplier (ALM). Besides comparing with the method of robust alignment by sparse and low-rank decomposition for linearly correlated images (RASL), we also propose a nonconvex penalized lowrank and sparse decomposition (NLSD) model as comparison. Numerical experiments are conducted on both controlled and uncontrolled data to demonstrate the outperformance of the proposed method over RASL and NLSD.