飞秒脉冲在光子晶体光纤中传输特性研究

光谱超连续展宽在光通信中有着重要的应用.文章用分步傅里叶法数值模拟了在不同色散区泵浦光子晶体光纤(PCF)中飞秒激光脉冲的传输特性和超连续谱的产生机理.研究发现:光纤色散和强非线性对飞秒脉冲在PCF中的传输、演化以及超连续谱的展宽都有很大影响.这些结论对于研究超连续谱的产生和应用具有参考意义.     

指数步降加寿试验分组数据的MLE与模拟分析

加速寿命试验在高可靠、长寿命的产品寿命估计中的应用愈来愈广泛,而步降应力试验方法能在较短的时间内获取足够统计精度的失效寿命数据,在很大程度上改善了加速寿命试验效率。对简单步降试验（即两步步降试验）所获得的分组数据进行统计分析,估计加速模型方程参数,给出了指数分布情形下的极大似然估计。模拟实例充分验证了该理论的可行性和有效性,为高可靠长寿命产品的评估提供了更为高效、低资的寿命试验解决方案,完善了加速寿命试验理论。     

用Prewitt算子细化边缘

传统的边缘检测算予一般都只能得到比较宽的边缘,这为以后的图像处理带来了一定的困难。本文通过对图像边缘特征的分析,提出了一种新的边缘细化方法——Prewitt算子细化边缘。实验表明,这种方法能在保持原有信息的前提下,给出令人满意的细化结果。     

CO2 miscible flooding in low permeability sandstone reservoirs and its influence on crude oil properties

Miscible CO₂ injection process has become widely used technique for the enhanced oil recovery in low permeability reservoirs. Core flooding experiments and field test of CO₂ miscible flooding in low permeability sandstone reservoirs and its influence on crude oil properties was studied. The results showed that CO₂ miscible flooding in low permeability sandstone reservoirs can enhance oil recovery both in laboratory study and field test. The permeability of sandstone reservoirs decreased during CO₂ miscible flooding due to the precipitation of asphaltene of crude oil. The precipitation of asphaltene lead to a reduction of asphaltene content and the apparent viscosity of crude oil. A further study on inhibitors and removers for asphaltene deposits from crude oil should be investigated to prevent and remove asphaltene deposits in low permeability sandstone reservoirs.     

整体异步的并行转换算法

针对Fukushima提出的求解无约束最优化问题的同步并行转换算法(PVT),提出一个整体异步并行算法,该算法去除了并行计算中同步与通信的开支。在一定的条件下,证明了该算法具有全局收敛性以及线性收敛速度。数值试验结果表明,异步PVT算法优于同步PVT算法。     

INTERWEAVING OF ABSENCES AND PRESENCES IN TONI MORRISON'S POSTMODERN PASTICHE TEXT BELOVED

<正>Beloved is one of Toni Morrison's most popular and influential novels.This text could be interpreted from various perspectives.In this paper,the author intends to explore this novel as a postmodern text,and tries to tackle the interweaving absences and presences of the characters and events in the novel.     

The influence of synthesis conditions on the crystal and aggregate properties of calcium salt azo pigment CI Pigment Red 48:2

The influence of pH and heating time at 80 °C on the final stage (conversion to the calcium salt) of the formation of the metal salt azo pigment, CI Pigment Red 48:2, has been investigated. A series of systematically prepared pigment samples were characterized by transmission electron microscopy, X-ray powder diffraction, surface area measurement and a detailed nitrogen adsorption–desorption isotherm investigation. Significant differences in the crystal sizes and morphologies and in the crystal growth patterns were observed. The colour and lightfastness properties in air-drying alkyd paints are correlated with the physical property data.     

The effect of slice thickness on potato crisp yield and composition

Potato tubers of cv. Record UK were used to produce crisps (chips) of different slice thickness (40–70 thousandths of an inch; 1-1·75 mm approximately) using an industrial slicer. The slices were examined to determine maxumum thickness variability of each slice and the range of values produced at each set thickness. Prepared crisps were analysed to determine the effect of slice thickness on the yield and composition of crisps. A series of regression equations were produced relating slice thickness and total surface area of slices to yield, moisture content and oil content of product. Oil uptake during frying was found to be related to the surface area of the potato slices.     

求解多组分化学相平衡的一种通用算法

基于Gibbs自由能最小原理,提出一种求解多组分化学相平衡的通用算法——混沌-蒙特卡罗混合算法。分别介绍了该算法的计算步骤和关键性能参数。多个计算实例表明,本文提出的方法可以不断拓展解的空间,避免假收敛,能以完全概率、高速并行搜索到全局最优解。