Extracting Silhouette Curves of NURBS Surfaces by Tracing Silhouette Points

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Arsenic removal from water by iron-sulphide minerals

In bench-scaled experiments, iron-sulphide minerals, pyrite and pyrrhotite are used as adsorbents for arsenic removal from As-spiked water of As⁵⁺ and As³⁺ species. The adsorption rate, efficiency, As-adsorption stability and the associated pH conditions have been examined. Observations indicate that these iron-sulphide minerals are very efficient to adsorb arsenic from water for both As⁵⁺ and As³⁺ species. Similar to other studies, As³⁺-adsorption shows a slower rate than As³⁺. The stability of the adsorbed arsenic seems closety retated to the pH values of the solution. A lower pH levet commonly less than 4.0 is required to protect the adsorbed arsenic from serious oxidation and backward retease. Fining of the mineral powders and shaking of the solution during adsorption enhance the adsorption efficiency and adsorption rate. For practical use of the method presented in this study, the waste produced should be managed with great care to keep it from redistribution over water system. A further study of the protection for the waste from oxidation on real water systems will greatly enhance the application of the strong ability of arsenic adsorption by these minerals, which is observed from this study.     

基于水平集曲率的图像滤噪与增强

分析了用于图像滤噪与增强的滤波技术特点，并针对偏催分方程（PDE‘s）模型给出新的数值计算方案，特别，多局部水平集曲率计算为算法的精细化提供了保证，在使用PDE‘s模型处理前,Canny边缘检测和数学形态学方法被应用估测边缘，滤除部分虚假边缘点，为针对不同区域折中使用不同的滤波方法提供了前提条件，实例分析以较小的计算量取得了较好的视觉质量。     

申村水库枢纽存在的问题及加固措施

针对申村水库存在的问题，制定了除险加固措施，提出了具体实施方案。     

A Combined System for Biological Removal of Nitrogen and Carbon from Nylon-6 Production Wastewater

A combined system consisting of hydrolysisacidification, denitrification and nitrification reactors wasused to remove carbon and nitrogen from the nylon - 6production wastewater, which was characterized by goodbiodegradability and high nitrogen concentration. Theinfluences of Chemical Oxygen Demand(COD) in theinfluent, recirculation ratio, Hydraulic Residence Time(HRT) and Dissolved Oxygen(DO) concentration on thesystem performances were investigated. From results itcould be seen that good performances have been achievedduring the overall experiments periods, and COD, TotalNitrogen(TN), NH -N and Suspended Solids(SS) in theeffluent were 53, 16, 2 and 24 mg·L-1, respectively,which has satisfied the first standard of wastewaterdischarge established by Environmental Protection Agency(EPA) of China. Furthermore, results showed thatoperation factors, viz. COD in the influent, recirculationratio, HRT and DO concentration, all had importantinfluences on the system performances.     

模拟石灰颗粒干式除酸的分形Bethe孔网模型

石灰颗粒的内孔结构对石灰吸收ＨＣl气体的反应进程起着决定作用，用Ｂethe网络来代表石灰颗粒内孔隙之间的连接性，用分形概念为描述内孔形状和表面的不规则性，从而建立全面考虑内孔连接特征和孔壁形态的不规则性的内孔结构模型，并对反应过程进行模拟计算。通过在２００－３００℃范围内，石灰颗粒吸收ＨＣl气体的反应率随时间进展的试验数据与数据模型预测相对比，表明模型计算与实验结果有较好的一致性。     

次临界系统中α本征值与k本征值的关系

以Godiva临界模型为基础,建立了两种次临界模型,并计算了两种模型中不同易裂变核材料含量的k本征值和α本征值。结果表明,并非k越小,α就会越小。对于含氢介质较多的系统,即使k很小,由于瞬发中子寿命很大,α也会接近于0,因而α不能直观地表征系统的临界特性,而k比α更适合这样的系统。对瞬发中子寿命较小的次临界系统,α绝对值较大,能直观地显示系统中子随时而间的衰减行为,对这种系统,使用α是合适的。     

试论集体土地房屋拆迁管理立法

长期沿用城市房屋拆迁的规定，无法很好地解决农村集体所有土地上农民房屋拆迁中遇到的实际问题。为加强集体土地房屋拆迁管理，维护拆迁当事人的合法权益，保障建设项目顺利进行，制定《集体土地房屋拆迁管理条例》彰显必要。     

SO3烟气调质技术在电除尘器上的应用

介绍SO_3烟气调质技术的原理、国内外SO_3烟气调质的工艺和装置以及SO_3烟气调质技术存在的问题,展望国内SO_3烟气调质技术的应用前景。     

册田水库除险加固的必要性及其初步设计方案

简要介绍了册田水库的基本情况,针对目前水库管理中存在的问题,探讨了水库除险加固的必要性及其初步设计方案。