The electrochemical behaviour of copper in sodium salicylate aqueous solutions

Cyclic voltammetry has been used to investigate the behaviour of copper surfaces in sodium salicylate aqueous solutions. The observed copper anodic passivation dependence on the presence of salicylate ion in solution is explained. The analysis of the experimental data supports the formation of a complex passivating film formed by a Cu₂O inner layer and a mixed cupric oxide/cupric salicylate outer layer; this film provides a partial passivation of the copper surface and can be completely removed upon excursion to negative potentials values; the composition of the passivating layer depends on the electrolyte nature, i.e. sodium salicylate ion and solution pH, and on the potential programme the copper electrode is subjected to.     

Design criteria for ideal foam nucleating agents

Design criteria for ideal foam nucleating agents, also called nucleants, are identified. Nucleants conforming to the criteria are expected to produce desirable foams with a large number density and narrow size distribution of bubbles. The criteria are based on an analysis of the thermodynamics and kinetics of coupled nucleation and growth. Based on this work, ideal nucleants have four characteristics. Nucleation on ideal nucleants is energetically and kinetically favorable relative to homogeneous nucleation. Ideal nucleants also have uniform geometry and surface properties, they are easily dispersed, and they are plentiful enough to overwhelm the contributions of homogeneous and unintentional heterogeneous nucleation.     

An evolutionary psychological perspective on gender similarities and differences.

Comments on the article by J. S. Hyde (see record 2005-11115-001), which reviewed the results of 46 meta-analyses of studies investigating gender differences and produced results that supported the gender similarities hypothesis that men and women are similar along most psychological traits. The current authors agree with the gender similarities hypothesis but argue here that Hyde's review has limitations that caused it to underestimate the true extent of gender differences. They also outline the benefits of adopting an evolutionary psychological perspective on gender differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

多孔介质中粘弹性液体广义流动分析

将分数阶导数引入渗流力学建立了多孔介质中具有松驰特性的非牛顿粘弹性液体的含有分数阶导数的不稳定渗流模型，利用离散逆Laplace变换技巧和广义Mittag-Eeffler函数研究了多孔介质中非牛顿松弛粘弹性液分数阶流动特征。对任意的分数阶导数得到了精确解，并先求出了长时和短时渐进解，然后用拉普拉斯数值反演Stehfest方法分析无限大地层粘弹性液的流动。结果表明粘弹性流体对分数导数的阶数具有极强的敏感性。     

视频点播技术与直播技术比较和在远程教学中的应用

文中简要的介绍和比较了4种视频点播和直播技术，并以Real技术为例讲述了如何在远程教学中使用视频点播和直播技术。     

单周期超短脉冲光束通过色散介质的传输

本文分析了单周期超短脉冲光束在色散介质中的传输特性，给出了相应的解析解。结果当脉冲宽度短至几个光学周期时，时空参量之间的耦全变得很重要，并将引起脉冲光束的非对称。     

基于IP的城域网流媒体服务系统设计

介绍了基于IP的城域网（MAN）流媒体服务系统的体系结构，指出未来的IP流媒体服务系统必然是集中和分布式相结合的服务平台；着重阐述了所涉及的几项关键技术及其可能的解决方案。     

二维叠偏剖面作构造图空校原理及方法

利用自激自收地震反射波原理在均匀介质条件下推导出地下反射点位置与射线路径、目的层视倾角、地震测线夹角及目的层埋深之间的复杂关系，并推广到层状介质条件下，计算反射点位置的偏移量及反射点到地面的垂直深度。用垂直深度作图，主测线联络测线可同时利用，精度高，形态逼真，断裂系统联接合理。此方法解决了目前二维叠加偏移剖面作图中存在的不闭合及数据为法线深度等问题。     

Two-dimensional flow towards a guarded downhole sampling probe: An experimental study

The guarded-probe concept for downhole fluid sampling is analogous to that of focused electrodes for borehole electrical measurements. The guard part of the probe surrounds the sample probe and draws fluid from the near-wellbore region of the rock formation where pore fluid is contaminated with drilling fluid filtrate (invasion fluid). Fluid entering the central sample probe comes from points deeper in the formation, where contamination is lower. We report experiments performed to study the guard probe concept in two dimensions. For these experiments, glass beads contained in a thin cell formed the porous medium. The original, uncontaminated pore fluid was an optical index-matching oil. The invasion fluid was the same oil with a dissolved dye. A camera recorded the displacement of the dyed fluid by the clear fluid and the dye concentration was measured in the flow lines through which fluid was withdrawn. The experiments verify that in 2 dimensions a guarded probe produces clean samples of original pore fluid faster than would a simple probe. The experiments were successfully modeled, without adjustable parameters, by means of a finite-difference numerical reservoir simulator and by computations based on an approximate velocity field given by a complex variable solution of the Laplace equation.     

色散媒质中采用Z变换的ADI-FDTD方法

基于Z变换方法将ADI-FDTD推广应用于色散媒质,得到了二维情况下色散媒质中的迭代差分公式,同时给出了一种采用ⅡR滤波器结构来减少存储量的方法.本文方法适合于任意M阶色散媒质,最后,给出了一个算例,数据仿真结果表明,本文的算法与传统色散媒质中的FDTD相比,在计算结果吻合的情况下,存储量相当,计算效率却更高,时间步长仅仅由计算精度来决定.