UO2 dissolution in Boom Clay conditions

The solubility of uranium dioxide (UO₂) was measured in real and synthetic Boom Clay waters with varying concentrations of humic acids and carbonate under reducing conditions at 20 °C. Uranium concentrations in function of time suggest the reduction of U(VI) to U(IV) by the humic acids which is occurring faster in real clay water than in synthetic clay waters. Humic acids induce also a competition to complex U(VI) in carbonate-containing solution, but they are not able to control the uranium concentration at high bicarbonate concentration (0.02 mol dm⁻³). Nevertheless they may play a role at low carbonate concentration. In our experimental conditions, the geochemical calculations indicate that two uranium secondary phases (U₄O₉ and UO_2(c)) are susceptible to control the uranium concentration in solution. These calculations are in good agreement with results of the X-ray photoelectron spectroscopy. At the end of tests, uranium concentrations reach steady-state values between 3 × 10⁻⁸ and 5 × 10⁻⁸ mol dm⁻³ in the bicarbonate-rich solutions. Although these concentrations are considered as conservative, they are 10-100 times higher than in natural Boom Clay. The consequence is that spent fuel could slowly dissolve in the interstitial clay water undersaturated with respect to UO₂/UO_2+x of the fuel.     

论高职院校体育文化的结构与优化

当前，我国高职院校体育化结构还处于非平衡状态。要从强化研究、投入以及化协作等多角度全方位进行优化，以适应社会主义市场经济对全面发展高等人才的需要。     

试论教学艺术在体育课中的运用

本从体育教学内容安排、组织管理、语言的运用、对学生的评价等六个方面对教学艺术在高校体育教学中的运用作了探讨。教学艺术在高校体育课教学中合理运用有利于提高教学质量，能够更好地为大学生的基础教育、素质教育服务。高校体育教师通过不懈的学习和努力，能够在教学实践中逐步形成自己独特的教学艺术风格。     

Preparation and characterization of Ni/Co bimetallic nano-clusters

Ni/Co bimetallic nano-cluters have been prepared from the aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions including the type and concentration of protective agent, feeding order and the pH of the solution that influence the average particle size have been studied in detail. Transmission electron microscopy (TEM) indicates that the shape of those bimetallic nano-cluster particles is spheroid. The alloy structure has been shown by X-ray powder diffraction (XRD). The X-ray photoelectron spectroscopic (XPS) data have confirmed that the nickel and cobalt in the bimetallic nano-clusters are in the zero-valence state.     

Semi-solid slurry preparation and rolling of 1Cr18Ni9Ti stainless steel

The preparation and rolling of the semi-solid slurry 1Cr18Ni9Ti stainless steel were researched. The experimental results show that when stirred for 2-3 min under the given test condition, the semi-solid slurry with about 50%-60% (volume fraction) solid and the spherical primary austenitic grains in the size of 100-200μm can be obtained, and it is easy to be discharged from the bottom little hole of the stirring chamber. The semi-solid slurry of 1Cr18Ni9Ti stainless steel can be rolled into the given plate successfully. However, the solid phase and liquid phase are easily separated in the rolling process, so that the solid primary austenitic grains are concentrated in the center and the liquid phase is near the edge of the rolled plate. The strengths of the plate rolled in the semi-solid state are higher than that of the traditionally repeated hot-rolled plate of 1Cr18Ni9Ti stainless steel.     

Modeling of Temperature and Residual Stress Fields Resulting from Impacting Process of a Molten Ni Particle onto a Flat Substrate

1　IntroductionAmoltenmetalparticleimpactingontoasubstrateundergoesrapiddeformationasitspreadsintoathinfilm ,associatedwiththeheattransferandthegenerationofthermalresidualstress .Thisprocessisofbroadgeneralimportanceinthermalsprayoperations ,becausethefinalflatteningshape ,thetemperaturedistributionandthere sidualstressfieldsareallrelatedtothemicrostructureofthethermalsprayingcoatings ,thusfurtheraffectingthequalityofthecoatings .Thesephysicalphenomenaareverycomplexandoccuroveraveryshorttimesc…     

高精度测量F-P标准具间距的光谱方法

利用高分辨率光谱分析仪对空气隙F P标准具透射谐振峰频率进行测量 ,然后通过直线拟合获得自由谱域 ,从而计算得出F P标准具的间距。对F P标准具间距测量的精度进行分析 ,F P标准具间距测量的相对误差为2× 10 -3 。提出了一种新颖的入射光与F P标准具垂直的精确调节方法     

基于I2C总线的键盘显示模块设计

介绍了利用P87LPC76X系列单片机设计的一个键盘显示模块，通过12C总线与主控芯片相连，具有灵活、控制方便等特点。文中给出了部分硬件设计和软件流程。     

主动式网络安全防御系统模型设计

依据动态信息安全模型P~2DR并结合现有的网络安全技术,作者提出了一个主动式的网络安全防御系统模型。本文介绍了模型的体系结构和信息处理流程,最后给出了模型的特点。     

P2P网络移动Peer的JXME平台的研究和实现

首先简要介绍了P2P网络、JXTA平台和JXME平台。针对当前JXME平台存在的不足，设计并实现了支持XML数据格式解析的系统性的JXME平台，通过KXML解析器和七个类的实现为应用程序透明地提供了各种服务。