Al_2O_3／Al－4Wt％Cu复合材料凝固时溶质传输及其对界面的影响

根据金属凝固过程中的守恒定律和传输原理，建立了Ａｌ２Ｏ３／Ａｌ－Ｃｕ复合材料凝固对溶质传输的数学模型．利用所建立的模型，对Ａｌ２Ｏ３／Ａｌ－４Ｗｔ％Ｃｕ复合材料凝固过程中的温度和成分分布以及凝固进程进行了数值模拟．研究了复合材料凝固时的溶质传输以及对纤维／基体界面的影响，讨论了溶质在界面富集的原因．     

排水条件下饱和土中氮肥转化与运移模拟

在室内试验的基础上，对施于水层中的氮肥（碳铵：ＮＨ４ＨＣＯ３）在饱和土中的转化与运移过程进行了数值模拟，测定了ＮＨ４＾＋－Ｎ在饱和土中转化和运移的有关参数。结果表明，土壤溶液中ＮＨ４＾＋－Ｎ的计算值与实测值的吻合程度是满意的。     

原状土壤动态吸附的理论和试验研究

本文根据固体颗粒吸附的基本特性和质量守恒定律,从数学物理角度推导了原状土壤动态吸附公式,并提出了确定参数的实验方法。通过对几种土壤的试验,结果表明,本文推导的公式比较成功地描述了原状土壤的动态吸附过程。     

Experimental Study of Preferential Solute Transportation During Dump Leaching

1 Introduction Low-grade mineral resources can effectively be recovered by dump leaching techniques. It is useful to extract metals from secondary sources such as dump- ing and waste disposal sites, tailing piles and so on. At present, dump leaching has widely been applied in mining of copper, gold, silver and uranium, because of its many virtues, such as simple and environment friendly techniques, lower investment and higher utilization rates[1–5]. Considerable economic and so- cial benefits…     

Optimization of control parameters of CdZnTe ACRT-Bridgman single crystal growth

Cadmium zinc telluride is widely used as a substrate material for CdHgTe epitaxyand efficient γ-detectors. However, it is rather hard to get high quality single crystal ofthis material. One of the key difficulties is the solute content segregation. First, it is noteasy to control the chemical compositions of CdxZn1 Te right exactly due to high-partial ?xpressures of the components. Secondly, its heat conductivity is so low that …     

三元合金稳态平面前沿凝固的溶质再分配

本文对稳态平面前沿凝固的溶质再分配进行了理论分析。分析表明,合金元素间的相互作用将影响溶质再分配,但这种作用小到可以忽略时,三元台金的溶质再分配类似于二元合金。合金元素间的这种相互作用程度可由(Coi/ki)来评定。当(Com/km)>(Con/kn)时,m 组元强烈影响n组元的再分配,使其分布曲线变得平坦,即阻碍其扩散。而 n 组元对 m 组元几乎没什么影响。当(Com/km)≈(Con/kn)时,二者互相影响。作者认为(Coi/ki)判据可用于多元合金凝固过程。     

Al-Mg-Si合金的凝固过程

研究了Al Mg Si合金的凝固过程 ,用不同方法测量了合金成分与冷却速度对该合金系铸态组织的影响。通过形态分析确定了Al Mg Si合金的凝固顺序 ,用EPMA测定了非平衡过程的溶质分布 ,并发现FeSiAl4～ 5相成分在高冷速时为FeSiAl5,而在低冷速时为FeSiAl4。晶界附近发现了无溶质带 (NSZ) ,并从固态扩散和凝固溶质再分配两个方面分析了NSZ的形成原因。     

非饱和土壤中吸附性溶质运移的基本方程和参数结构

本文应用随机场的谱分析方法，研究了吸附性溶质在非饱和，非均匀土体中运动时平均浓度所遵循的基本方程。当非饱和水分运动以重务为主要作用力时，设经对数变换后的土壤饱和渗透系数，吸附系数和α参数为正态平稳随机场，求得了宏观弥散度的解析表达式。研究结果表明，宏观散度由三部分组成，分别来源于非饱和渗透系数的自相关函数，非饱和渗透系数吸附参数的互相关函数，以及吸附参数的自相关函数。     

Applications of the concept of river tracer data similarity

The response of a river to a pollution incident is heavily influenced by the river's flow rate. To capture the full range of this response, tracer experiments are often used. The paper discusses how the concept of similarity of temporal concentration profiles can be used to better exploit the information content of such experiments. Examples are given showing that poor quality tracer data that might be thought to be of little use may yet contain valuable information. Extracting this information has the potential of improving predictions of pollutant travel times, in particular, as well as offering the prospect of improving estimates of flow rates (via dilution gauging) and dispersion coefficients (via several methods).     

基于FEFLOW的油库污染物渗漏模拟研究

针对油库正常运行中可能出现的渗漏污染问题,以云南省某地下油库为研究对象,利用FE-FLOW软件,采用数值分析方法,对研究区内典型污染物在不同工况下的污染物迁移进行模拟.计算结果表明,在正常工况下,污染物的影响范围随时间增加而增大,但是影响范围未超出厂区,不会对周边环境造成污染;在油库防渗层失效的非正常工况下,污染物的扩...