复合流场上吸罩流场理论分析

提出在计算复合流场内存在两种不同流态的流动:势流和紊流。针对两种流动,分别建立了其数学模型,对于紊流流场,针对标准k-ε紊流模型的缺陷,采用了RNGk-ε紊流模型使紊流控制方程封闭。以及提出了边界条件的确定原则。为复合流场的数值计算提供了理论指导。     

Corrosion Inhibition Mechanism with Spilt Cell Technique of Rare Earth Metal on LC4 Al Alloy

A new method of studying the corrosion inhibition mechanism of rare earth metal(REM) on LC4 Al alloy with the spilt cell technique was studied. The principle and experimental method of the spilt cell technique were analyzed. By measuring the change of net-electric current between the two electrodes caused by the change of the amount of oxygen in the solution and the addition of CeCl₃, the influence of corrosive performance of CeCl₃ on LC4 super-power aluminum alloy in the 0.1 mol·L⁻¹ NaCl solution was investigated. Meanwhile, the conditional changes of pH values, CeCl₃ solution, additire and time of performance were also studied. Finally, the features of electrode surface were revealed by using SEM and X-ray energy-dispersive spectrometry (EDS). By combining these with other electric chemical techniques, such as potential-time curve, polarization curve et al.     

油显示分析仪测定有机碳的替代容量分析

本介绍油显示分析与容量分析中非水滴定测定的有机碳结果对比及替代建议。统计结果，两种方法分析结果是等效的，具有相同的精度。     

Diffusion Behaviour of Fe-Cu Interface of Copper Brazed Double-wall Steel Tubes

By means of electron probe(EPMA),scanning electron microscope(SEM),and optical microscope(QM),the diffusion behaviour on the Fe-Cu interface of copper brazed double-wall steel tubes andthe microstructure of the diffusion layer have been investigated.There are three kinds of metallurgicalbonds between copper plating layer and steel substrate: (1)the Cu diffusing into steel substratealong grain boundary of ferrite;(2)the Cu diffusion into grain bulk of ferrite: (3)the Fe diffusing intoCu layer.The copper brazed double-wall steel tubes are formed by the combination of the diffusionsmentioned above and this is the reason for excellent mechanical and technological properties of thecopper brazed double-wall steel tubes.     

Analytical modeling and experimental study of tensile strength of asphalt concrete composite at low temperatures

In this study, analytical modeling of the tensile strength of hot-mix asphalt (HMA) mixtures at low temperatures was developed. To do this, HMA mixtures were treated as a two-phase composite material with aggregates (coarse and fine) dispersed in an asphalt mastic matrix. A two-phase composite model, which was similar to Papanicolaou and Bakos's [J. Reinforced Plast. Compos. 11 (1992) 104] model with a particle embedded in an infinite matrix, was proposed. Unlike Papanicolaou and Bakos's model, an axial stress was introduced to the fiber end to consider the load transferred from the asphalt mastic the aggregate. Efforts were also made to consider the effect of aggregate gradation, asphalt mastic degradation, and interfacial damage between the aggregates and asphalt mastic matrix on the tensile strength of the HMA mixtures. Experimental investigations were conducted to validate the developed theoretical relations. A reasonable agreement was found between the predicted tensile strength and the experimental results at low temperatures. Parameters affecting the tensile strength of asphalt mixtures were discussed based on the calculated results.     

碱金属和锌对高炉用SiAlON结合刚玉砖的复合侵蚀

将高炉用SiAlON结合刚玉砖制成外部尺寸为50mm×50mm,内孔尺寸为25mm×25mm的坩埚,分别加入由Na2CO3、K2CO3、ZnO和宝钢高炉现场高炉灰配制的炉渣(其w(Na2O+K2O)=2.75%,w(ZnO)=5.1%)和用K2CO3、ZnO、石墨配制的炉渣(其w(Na2O+K2O)=25%,w(ZnO)=25%),然后分别在还原气氛下于1350℃16h和1100℃40h进行侵蚀试验。将侵蚀后的试样纵向对称剖开,观察渣对试样的侵蚀和渗透情况,进行SEM和EDAX分析。结果表明:碱金属和锌含量不同的两种炉渣对SiAlON结合刚玉砖的侵蚀速度都很小;碱金属侵蚀机理主要是SiAlON与碱蒸气反应生成钾霞石,与渣反应生成铁橄榄石,并参与硅酸盐玻璃相的生成;刚玉颗粒与渣中的FeO、Na2O和K2O反应生成铁铝尖晶石和少量针状β-Al2O3;锌对该砖没有产生明显的化学侵蚀。     

电除尘器绝缘子的设计与选择

根据电除尘器绝缘子的功能及工况条件，介绍了材质和结构形式的选择。对于电除尘器绝缘子材质的选择，首先要考虑承受运行电压的能力，其次是耐温性能和机械强度。对于结构形式的选择，应考虑有足够的厚度以耐电力冲击、足够大的爬电距离以防漏电或对地闪络、足够大的空间以防出现电晕或空间闪络。另外，介绍了高铝瓷绝缘子的成功应用及其优点。     

纳米棒状氧化铁红的制备及表征

以尿素为沉淀剂,采用缓慢滴加方式,用均匀沉淀法制备了纳米棒状氧化铁红。考察了Fe^2＋浓度、反应时间、反应温度、尿素与Fe^2＋物质的量比等因素对产品粒径、形貌及收率的影响,并用TG,XRD,IR,UV-VIS,TEM等对样品进行了表征。确定了制备纳米棒状氧化铁红的最佳工艺条件：Fe^2＋浓度为0.50 mol/L,反应时间为180 min,反应温度为80℃,尿素与Fe^2＋物质的量比为20∶1,在此条件下制得前驱体,将前驱体在350℃下煅烧2 h,即可得到纳米棒状氧化铁红。样品的XRD,TEM表征结果为六方晶系的纳米棒状α-Fe2O3,其长轴约为300-500 nm,短轴约为20-40 nm,产品收率为75.90%,颜色为鲜红色,含质量分数5%样品的清漆对紫外线具有很好的吸收性能,而对可见光具有良好的透明性,其透光率在85%以上,可作为透明氧化铁红颜料使用。     

钢包粘渣与包衬耐火材料

阐明了钢包粘渣与包衬耐火材料存在一定的关系 ,抗渣渗透性差、容易出现开裂的包衬耐火材料容易粘渣。为防止钢包粘渣 ,适于采用抗侵蚀性和抗渣渗透性优良的尖晶石砖、铝尖晶石 (或铝镁 )浇注料、低密度浇注料以及抗剥落性好的刚玉 -锆英石浇注料作包衬耐火材料     

碳离子注入纯锆后在1 mol/L硫酸溶液中的腐蚀行为

为了研究碳离子注入对纯锆耐蚀性的影响,用MEVVA源对纯锆样品进行了1×1016ions/cm2至1×1017ions/cm2的碳离子注入,注入加速电压为40 kV.用X射线光电子能谱(XPS)和俄歇电子谱(AES)分析了注入样品表层元素的价态和深度分布.透射电镜(TEM)用来观察碳离子注入样品的微观结构;碳离子注入样品后相结构的变化用掠角X射线衍射(GAXRD)来检测.纯锆注入样品随后浸入1 mol/L的硫酸溶液中,测其极化曲线以评价其耐蚀性.发现碳离子注入极大地提高了纯锆基体的耐蚀行为,剂量越高,耐蚀性越好.最后,对碳离子注入导致纯锆基体腐蚀行为发生改变的机理进行了讨论.