Adsorption equilibria between dye and surfactant in single and binary systems onto geological materials

Adsorption characteristics of cationic dyes and surfactants onto clay and sandstone from a single component system were studied using toluidine blue (TB) and cetyl trimethylammonium bromide (CTAB). Equilibrium data of TB and CTAB in the single solute systems fit well to the Langmuir and the Freundlich adsorption isotherms. Competitive adsorption was observed between dye and surfactant cations. The effect of sodium chloride on dye and surfactant adsorption was studied in TB–NaCl and CTAB–NaCl binary systems. Equilibrium adsorption for binary systems was analyzed by using the extended Langmuir and the extended Freundlich models. Adsorption results for the TB–CTAB system onto both adsorbents were also well described by the Sheindorf–Rebuhn–Sheintuch (SRS) model for multi-component systems. Free energy changes for adsorption systems were calculated using thermodynamic equilibrium constants evaluated from selectivity coefficients of the binary systems. The site distribution functions estimated using Freundlich model parameters gave valuable information about the ratio of the adsorption sites on adsorbent surface having different affinity for competing cations.     

New learning rules for the ASSOM network

The ASSOM is a self-organising neural network with the capability of adapting to linear subspaces. Here we propose two new methods to train the ASSOM network. A nonlinear system of equations is derived for network training. This system can be solved by a gradient-based approach or by the Levenberg–Marquardt method. Each of these two approaches gives a different learning rule. A comparison is carried out among the original Kohonens method and the proposed learning rules. Experimental results are reported, including a convergence speed experiment and a speech processing application, which show that the new learning rules have better performance than the original one.     

An On-Line Multi-CBR Agent Dispatching Algorithm

Case-based reasoning (CBR) is an effective and fast problem-solving methodology, which solves new problems by remembering and adaptation of past cases. With the increasing requests for useful references for all kinds of problems and from different locations, keeping a single CBR system seems to be outdated and not practical. Multi-CBR agents located in different places are of great support to fast meet these requests. In this paper, the architecture of a multi-CBR agent system is proposed, where each CBR agent locates at different places, and is assumed to have the same ability to deal with new problem independently. When requests in a request queue are coming one by one from different places, we propose a new policy of agent dispatching to satisfy the request queue. Throughout the paper, we assume that the system must solve the coming request by considering only past requests. In this context, the performance of traditional greedy algorithms is not satisfactory. We apply a new but simple approach – competitive algorithm for on-line problem (called ODAL) to determine the dispatching policy to keep comparative low cost. The corresponding on-line dispatching algorithm is proposed and the competitive ratio is given. Based on the competitive algorithm, the dispatching of multi-CBR agents is optimized.     

战略成本管理的利器--业务外包

本文从分析业务外包的内涵开始入手 ,阐述了其对战略成本管理的意义 ,以及实施业务外包降低成本以获取竞争优势的主要途径     

Online algorithms for searching and exploration in the plane

In this paper, we survey online algorithms in computational geometry that have been designed for mobile robots for searching a target and for exploring a region in the plane.     

延边区域竞争优势的源泉--全球化背景下的企业集群

企业出现以来，企业组织形式随着技术进步和市场需求的变化不断演进．21世纪，中小企业和企业集群逐渐成为主流，并成为全球化背景下延边区域竞争优势的源泉．本文立足延边现状，分析了延边企业集群的类型选择和发展问题，并提出了对策．     

基于电子商务环境下的中小企业核心竞争力构建探究

电子商务的出现为中小企业提供了快捷廉价的信息和服务,扩宽了中小企业的发展空间,为中小企业核心竞争力的提高创造了条件。本文分析了中小企业核心竞争力的现状,提出了我国中小企业在当前电子商务背景下存在的问题,并提出从开发核心技术、建立规范的企业制度、制定企业的战略目标以及创建企业特色的企业文化四个方面采取措施来提高核心竞争力。     

Transmission congestion and voltage profile management coordination in competitive electricity markets

This paper describes a generalized active/reactive iterative coordination process between GENCOs and the Independent System Operator (ISO) for active (transmission congestion) and reactive (voltage profile) management in the day-ahead market. GENCOs apply priced-based unit commitment without transmission and voltage security constraints, schedule their units and submit their initial bids to the ISO. The ISO executes congestion and voltage profile management for eliminating transmission and voltage profile violations. If violations are not eliminated, the ISO minimizes the transmission and voltage profile violations and sends a signal via the Internet to GENCOs. GENCOs reschedule their units taking into account the ISO signals and submit modified bids to the ISO. The voltage problem is addressed and a linear model is formulated and used in the proposed method. The voltage problem is formulated as a linear programming with a block-angular structure and Dantzig-Wolfe decomposition is applied to generate several smaller problems for a faster and easier solution of large-scale power systems. Two 36 unit GENCOs are used to demonstrate the performance of the proposed generalized active/reactive coordination algorithm.     

Competitive Separation of Lead,Cadmium, and Nickel from Aqueous Solutions Using Activated Carbon: Response Surface Modeling,Equilibrium, and Thermodynamic Studies

In this study, the competitive separation of lead, cadmium, and nickel ions from aqueous solutions using a commercial activated carbon (AC) has been investigated and optimized using response surface methodology (RSM). The optimal conditions to reach the highest adsorption capacity for these metals were found as follows: initial pH = 6.3, temperature = 56.8°C, and shaking speed = 308 rpm. Under these conditions, the sequence of adsorption capacity toward the metal ions was as follows: Pb (II): 9.44 mg g^?1 > Cd (II): 9.37 mg g^?1 > Ni (II): 4.52 mg g^?1. The effect of shaking speed on the adsorption capacity of AC was higher than the effects of the initial pH and temperature, indicating the more important role of physisorption than chemisorption in the adsorption of these metal ions. This was confirmed by the results of thermodynamic studies. The equilibrium adsorption data were fitted to the Freundlich, Langmuir adsorption isotherm models and the Dubinin–Radushkevich model parameters were evaluated. All the models were tested and all were shown to represent the experimental data satisfactorily. The thermodynamic parameters such as ΔH, ΔS, and ΔG were computed from the experimental data. These values show that the adsorption is endothermic and spontaneous. The positive value of ΔS° indicates increasing of randomness at the solid/liquid interface during the adsorption of metal ions on AC.     

总银杏酸对酪氨酸酶活性的影响及动力学研究

研究了总银杏酸(C13∶0,C15∶1,C17∶2,C15∶0,C17∶1)对酪氨酸酶单酚、二酚酶活力的影响及其抑制动力学。在28℃,p H=6.8的Na2HPO4-Na H2PO4缓冲体系中,测试总银杏酸对酪氨酸酶催化反应进程的影响、酶活性抑制率以及抑制动力学参数。实验表明,总银杏酸对酪氨酸酶单酚酶和二酚酶活性均有抑制作用,单酚酶和二酚酶活力下降50%的总银杏酸质量浓度(IC50)分别为0.03 g/L和0.20 g/L。总银杏酸能延长单酚酶反应的迟滞时间,对二酚酶的抑制作用表现为可逆效应。Lineweaver-Burk图显示总银杏酸对二酚酶的抑制作用表现为竞争性抑制,抑制常数KI=75.20 mg/L。