拜耳法赤泥沉降槽的技术改造

研究内循环自稀释技术在拜耳法普通赤泥分离沉降槽中的试验应用情况。实践证明普通赤泥分离沉降槽的产能可以提高15.2%,清液层增加84.6%,溢流浮游物降低38.9%。     

膜技术在含油废水处理中的应用及研究现状

膜技术是一种高效、低能耗和易操作的液体分离技术 ,在废水处理领域的应用范围和规模日益扩大。文章介绍了含油废水的来源与危害及其一般的处理方法 ,概述了膜技术在含油废水处理领域的应用研究现状 ,认为膜技术是 2 1世纪水处理领域的优选技术。     

RBAC模型中角色的继承与互斥问题的研究

RBAC (Role-Based Access Control)maps naturally to an organization's structure and facilitates safety administration by separating logically users and permissions via roles as well as constructing role hierarchies, and therefore RBAC offers a powerful means of specifying access control decisions and is attracting increasing attention. In role hierarchies of RBAC,superroles inherit all properties and permissions of subroles. This paper classifies role inheritance into two types : generalization inheritance and supervision inheritance . Furthermore, it outlines two problems in relation to role inheritance :one is how to maintain data integrity,another is how to reduce the effect of absent roles on the normal running of the system. At last ,this paper discusses solutions to them 。RBAC is attracting increasing attention as a security mechanism .Separation of duty is an important safety requirement which is implemented by means of mutual exclusion of roles in RBAC. This paper presents a basic RBAC model,then explores some properties of mutual exclusion of roles,which helps enforcing security policies efficiently. At last ,this paper describes how mutual exclusion of roles affects role hierarchies.     

基于角色的访问控制

信息安全技术领域一个非常重要的方面是访问控制。文章描述了近年提出的一种新的访问控制技术RBAC。详细介绍RBAC的基本要素及NIST的RBAC四层模型,讨论比较了RBAC模型与TCSEC中的MAC和DAC的区别,最后分析了NISTRBAC四层模型的一些不完善之处。     

实时控制传输中的数据"粘连"算法分析研究

工程项目中对实时控制的要求比较高，而TCP／IP对小数据包无法实时传输，且有数据粘连现象。本文对这种现象从原理上进行了分析，结合常用的解决方法提出了自己的解决思路。     

电极生物膜脱氮工艺中反硝化菌相分析

对电极生物膜反硝化脱氮反应器中存活的反硝化菌进行了初步的分离及菌相分析研究,实验共分离出40株菌株,通过对菌株的形态观察及生理生化特征的研究表明,这些菌株分别属于假单胞菌属(Pseudomonas), 不动杆菌属(Acinetobacter), 肠杆菌科(Enterobacteriaceae)3个属,肠杆菌科、假单胞菌属为主要优势菌,占总鉴定菌数的82.5%.在异养环境中分离的24个菌株中,肠杆菌科为优势菌,具有反硝化能力的有18株,占75%;反硝化能力强的有8株,占33.3%.在自养环境中分离的16个菌株中,假单胞菌属为优势菌,其中具有反硝化能力的有12株,占75%;反硝化能力强的有8株,占50%.     

含氟铍矿石冶炼过程中氟的分离工艺研究

对含氟铍矿石冶炼过程中的氟分离工艺进行了研究。当矿石F/BeO=20%～40%时,采用沉淀分离法可以控制氢氧化铍的F/BeO=10%～12%。氢氧化铍经二次除铝、碱洗,可使产品中杂质Al2O3达到低于0 7%的要求。与矿石预处理工艺相比,沉淀法可使每吨氧化铍总成本降低约5000元左右。     

减少机动车对居住小区环境干扰的几种方式

从道路规划上着手解决居住小区内日益增加的人车混杂问题,强调只要通过简单的方法就可以有效地规划居住小区内人车分流交通系统,或使居住小区内人车共存变得更加和谐.     

Treatment of High Nitrate-Containing Wastewaters by Sequential Heterotrophic and Autotrophic Denitrification

The treatment performance of sequential heterotrophic and autotrophic denitrification process was evaluated using synthetic wastewaters containing high nitrate concentrations. The effluents from two sequentially connected reactors, for heterotrophic denitrification and sulfur-based autotrophic denitrification, were analyzed for more than 200 days. Experimental results indicated that higher than 95% of the nitrate removal could be achieved with volumetric nitrate loading rates of 2.16, 3.24, and 4.32 kg/m3?d. The maximum denitrification rates, with 1,000 mgN/l influent nitrate concentrations, for the heterotrophic and sulfur-packed autotrophic reactors, were found to be 2.47 and 3.61 kg/m3?d, respectively. A sequential heterotrophic and autotrophic denitrification process is considered a good alternative for the sole autotrophic denitrification process, providing excellent nitrate removal, especially for nitrate-rich wastewaters with very low organic contents.     

PROFIBUS现场总线和软PLC在色谱分离中试装置中的应用

介绍了现场总线和软PLC的特点，根据一套色谱分离中试装置的特点和生产工艺要求，设计了一套基于PROFIBUS总线的控制系统，具体描述了控制系统的结构、任务分配及实现、软件设计思想。