驱动场作用下光子晶体中的光场-原子束缚态

光子晶体中光子带隙的存在导致光场 -原子束缚态的存在。该束缚态的性质与镶嵌在光子晶体中原子的个数、原子的能级结构、能级相对光子带隙边缘的位置以及有无驱动场有关。利用求束缚态本征波函数的方法 ,讨论了光子晶体中一个三能级原子在相干场驱动下 ,由于光和原子之间的相互作用产生束缚态的性质。分析了在各种束缚态下原子各能级的粒子数布居随驱动场拉比频率的变化。分析结果表明 ,系统中存在多重束缚态 ,而且与上能级相对光子带隙的位置有关 ,当上能级位于带隙外时 ,只有一个本征束缚态 ,且原子几乎不能停留在上能级 ;当上能级在带隙内时 ,有两个本征束缚态 ,且两个本征束缚态的性质截然不同 ,原子各能级的粒子数布居随驱动场参数变化很明显     

SIMSAFADIM: three-dimensional simulation of stratigraphic architecture and facies distribution modeling of carbonate sediments

We present a three-dimensional simulation model for production, transport and deposition of carbonate sediment. Carbonate production is calculated from population dynamics of carbonate producing organisms. The population dynamics are simulated using a predator–prey model, which includes various effects such as competition with other species, internal competition, effects of mud and suspended carbonate sediments on carbonate producing organisms and depth dependent growth functions. Fluid flow is simulated as a steady-state potential flow using a finite-element model. Transport of suspended sediment is calculated including diffusive, dispersive and advective components. Deposition of suspended carbonate matter is calculated as a function of flow velocity, water depth and settling velocity of suspended carbonate matter. Its flexibility in representing ecologic processes and boundary conditions for flow and sediment transport permits the computer model to be applied to a wide range of possible situations in carbonate systems. A sample experiment is presented to demonstrate the capabilities of the model.     

Characteristics of multistage column crystallizer for gas-liquid reactive crystallization of calcium carbonate

Crystallization of calcium carbonate using a gas (CO₂)-liquid (Ca(OH)₂) reaction was conducted using a three-stage column crystallizer. In this study, the staging effect of the multistage column crystallizer and the effect of the operating parameters on the particle size distribution were experimentally and theoretically investigated. From an economic viewpoint, the multistage column crystallizer has been developed to replace a cascade of MSMPR crystallizers, which requires a large installation area and high operating cost because some crystallizers are connected in a series. In the multistage column crystallizer, a narrower particle size distribution was obtained compared to that obtained in the standard column crystallizer. The theoretical approach to predict the particle size distribution is based on the population balance equation which takes account of the back flow into the crystallizer. The calculation results of particle size distribution fairly coincide with the experimental results, which indicates the particle size distribution in the multistage column crystallizer can be roughly predicted by this theoretical model.     

Annual variation of fresh water quality in the Gachang Dam reservoir

This paper investigated the relationship between the annual variation of the algae population and the physicochemical properties of the water reservoired in the Gachang Dam in the hopes of serving as a guideline in the production of a clean water supply to regions of the city of Taegu. Summer thermal stratification was formed in the freshwater reservoired in the Gachang Dam and thus dissolved oxygen (DO) decreased according to the depth of the water. The pH of epilimnion was much higher than that of hypolimnion in summer because of the difference in the photosynthesis rate of algae. In July, at the beginning of the rainy season, the amount of total nitrogen (T-N) in the freshwater reached a maximum of 1.92 mg/L without an increase in the amount of total phosphorus (T-P). In August, the concentration of T-P in the freshwater increased steeply and reached 0.12 mg/L.Aulacoseira spp. (diatoms) were predominantly distributed in the freshwater throughout the year andSynedra andAsterionella (diatoms) predominantly populated in the spring. However,Anabaena andMicrocystis (blue-green algae), which caused malodor and a bad taste, flourished predominantly in epilimnion in August when the temperature of the water at the surface region increased to the maximum and the concentration of T-P was sufficiently high.     

Population variation in genetic programming

A new population variation approach is proposed, whereby the size of the population is systematically varied during the execution of the genetic programming process with the aim of reducing the computational effort compared with standard genetic programming (SGP). Various schemes for altering population size under this proposal are investigated using a comprehensive range of standard problems to determine whether the nature of the “population variation”, i.e. the way the population is varied during the search, has any significant impact on GP performance. The initial population size is varied in relation to the initial population size of the SGP such that the worst case computational effort is never greater than that of the SGP. It is subsequently shown that the proposed population variation schemes do have the capacity to provide solutions at a lower computational cost compared with the SGP.     

Probabilistic GRASP-Tabu Search algorithms for the UBQP problem

This paper presents two algorithms combining GRASP and Tabu Search for solving the Unconstrained Binary Quadratic Programming (UBQP) problem. We first propose a simple GRASP-Tabu Search algorithm working with a single solution and then reinforce it by introducing a population management strategy. Both algorithms are based on a dedicated randomized greedy construction heuristic and a tabu search procedure. We show extensive computational results on two sets of 31 large random UBQP instances and one set of 54 structured instances derived from the MaxCut problem. Comparisons with state-of-the-art algorithms demonstrate the efficacy of our proposed algorithms in terms of both solution quality and computational efficiency. It is noteworthy that the reinforced GRASP-Tabu Search algorithm is able to improve the previous best known results for 19 MaxCut instances.     

无障碍的老年人人居环境的实现

从世界及中国的人口老龄化问题出发，通过对老年人的行为变化特点和我国养老的社会、经济、文化背景分析，提出了我国现阶段以社区和家庭养老为主、社会养老为辅的养老模式。针对这种养老模式，对适合我国老年人居住的、无障碍的人居环境规划提出了具有实践意义的对策，并阐述了所需要的社会支持体系。     

Assessment of the presence and dynamics of fungi in drinking water sources using cultural and molecular methods

A comparison of different isolation techniques and culture media for detection of filamentous fungi and yeasts in the aquatic environment revealed that the use of membrane filtration with the media dichloran rose bengal chloramphenicol (DRBC) optimized fungi detection in terms of abundance and variety in three untreated water sources with very different characteristics (surface water, spring water, and groundwater). The diversity of the fungi population captured by direct DNA extraction of fungi collected by membrane filtration was compared with the isolates obtained after selective growth using different culture media through amplification of the internal transcribed spacer gene and denaturing gradient gel electrophoresis (DGGE). The Czapek-Dox agar, Sabouraud dextrose agar, and DRBC media showed closer similarities to those obtained by the uncultured biomass for the different water sources. Based on these data and the best enumeration results, DRBC is recommended for the assessment of fungi in water sources using culture-based methods. DGGE was also used to monitor temporal variations in the fungal population structure and showed that each water matrix possessed a distinct population profile as well as that changes in the fungal community can be expected in the different matrices throughout the year.