Molecular simulation for adsorption of chlorinated hydrocarbon in zeolites

Equilibrium and isosteric heat of adsorption for the system of chloroform and USY-type zeolite were studied. The USY-type zeolite (PQ Co., SiO₂/Al₂O₃=70) was used both as a pure crystalline powder and as granulated particles with binder. Chloroform was reagent grade. The adsorption equilibria were measured using a gravimetric method and were expressed as isotherms. A chromatographic method (i.e. pulse response of chloroform through the USY column with helium carrier) was used to get the initial slope of the isotherms. In the simulation, the GCMC method was used to calculate amounts adsorbed for various conditions. FF parameters were confidently applied. And modified structure model was effective for simulation. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.     

从大观园探曹雪芹的造园思想（一）

曹雪芹撰写《红楼梦》的时间是乾隆九年至二十四年之间。正是北京园林建设最为兴旺发达的时期。文学艺术是现实生活的反映,而大观园就是北京园林建设发展的真实写照。从建筑学的角度分析大观园,是由六个具有各自鲜明特色的景区所组成,充分体现了曹雪芹的九大造园思想。     

京杭运河杭州段水污染源特征与截污措施建议

京杭运河杭州段地势低洼,一直是杭州城市和沿线郊区的污水受纳场所。经调查,在城区运河干流沿线两岸的合流管线污染源共有521处,其中生活污染源占95.2％,排入运河主河道污水量21820 m3／d。采用等标污染负荷法评价污染源,得出主要污染源80个,主要污染物为COD、BOD和NH3-N。提出了截污的基本原则和设想。     

申遗背景下淮安运河文化遗产保护与利用研究

在京杭大运河两千多年的发展史上,淮安一直处于重要的转轴地位,淮安运河文化遗产具有密集性、典型性、系统性等特征。最近几年,随着运河＂申遗＂工作的展开,京杭大运河淮安段受到空前重视。淮安采取了开展专题研究、编制保护规划、修缮运河文物等措施,加强了对运河文化遗产的保护和研究。     

基于污染损失率模型的京杭大运河水体评价——以扬州段为例

以污染损失率模型作为理论模型,选取高锰酸盐指数、BOD5、NH3-N、挥发酚和石油类等污染因子对京杭大运河扬州段水体功能的受污染程度及其造成的使用功能价值损失进行了估计,得出了京杭大运河扬州段的年均污染损失率和综合污染损失率。基于实证分析结果,以综合污染损失率1%、20%、50%、80%作为分级标准点,对运河扬州段的水体功能污染损害程度进行了系统划分后,由综合污染损失率模型计算得出京杭大运河扬州段目前处于轻微损害级别,并提出扬州段相应的水污染治理方案及措施。     

线型旅游空间研究——以京杭大运河为例

在旅游地空间结构和相关线状空间研究的基础上,借鉴在世界遗产保护领域的先进理念文化线路,提出线型旅游空间概念,界定为基于遗产保护进行旅游开发的旅游地空间类型.以京杭大运河为例,将其空间特征总结为历史悠久、跨越区域、文化多元和产品趋同等4个主要方面,并在此基础上提出了对大运河旅游规划的启示,应树立保护为先的理念,在全局的视角下避免目前的旅游形象和旅游产品趋同的现象,进行多角度的差异性定位;同时,基于大运河的大尺度、跨区域性,提出建立相应机构加强协调管理,并进行流域联合营销和区域联合营销.     

Solving constrained combinatorial optimization problems via importance sampling in the grand canonical ensemble

Combinatorial optimization problems are usually NP-hard. These problems are generally tackled by heuristic or branch-and-bound methods. The aim of this paper is to tackle constrained combinatorial optimization problems by importance Monte Carlo sampling. For this, we show that every constrained combinatorial optimization problem can be represented by a thermodynamical system in a suitable grand canonical ensemble given by the quantities of temperature, volume, and chemical potential. In order to find optimum solutions of the optimization problem, the grand canonical Monte Carlo method can be applied to the corresponding thermodynamical system. This method will amount to importance sampling, i.e. good feasible solutions of the optimization problem will be preferably sampled, provided that the intensive quantities of temperature and chemical potential are appropriately chosen. Our approach extends the standard importance sampling approach in the canonical ensemble to tackle unconstrained combinatorial optimization problems. The knapsack problem is considered as a prototype example.