Boehmite Nanoparticles by the Two-Reverse Emulsion Technique

Boehmite (γ-AlOOH) nanoparticles were successfully synthesized by the two-reverse emulsion technique at 90°±1°C under constant agitation with varying Al³⁺ concentrations in the aqueous solution. A mixture of cyclohexane and the surfactant, sorbitan monooleate (Span 80), constituted the support solvent in the reverse emulsions. The synthesized particles were characterized by thermogravimetry, differential thermal analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size analysis, and transmission electron microscopy (TEM). XRD and FTIR results confirmed crystalline boehmite formation at 90°±1°C. The average particle size of boehmite was found to be 10 nm. The spherical morphology of the boehmite nanoparticles was confirmed by TEM.     

成人级“儿童片”？

最近好像流行转型，冯小刚拍起了战争片，而星爷则开始拍“儿童片”。相比冯导的《集结号》，星爷的这次转型并不太成功，当然，这只是就电影本身而言。在商场上，星爷早已大获成功，除了票房收入，Intel的广告费、电影周边的玩偶疯卖，早已让星爷赚得盆满钵满了。     

Distributions of electric and elastic fields at domain boundaries

In this paper we describe the application of the finite element method (FEM) in modelling spatial distributions of electric and elastic fields in a ferroelectric crystals with two domains separated by a 90° domain wall. The domain boundary is idealized as a two-dimensional defect in an electro-elastic continuum. It represents the source of inhomogenity and internal distortion in both elastic and electric fields. The main results are distributions of electric field, strain and mechanical force along the domain boundary.     

Polymer holography I – Method and experiment

Summary Processes of radical photopolymerization running during the holographic exposition in photopolymer recording materials are investigated. Special experimental setup, which makes recording and continuous measuring of the forming hologram possible, was built up. An acrylamide-based recording material was prepared and tested. Our experiments verified that addition of bis-acrylamide improves the stability of the hologram due to micronetwork formation.     

Removing as from converter dust by a hydrometallurgical method

Research has been conducted at the Faculty of Metallurgy, Technical University, Kosice, to develop a hydrometallurgical method for removing arsenic from copper converter dust. The process consists of a selective leaching of the flue dust in which arsenic is dissolved in sodium-sulfide solution and then removed by precipitation methods using various agents: copper sulfate, a mixture of phosphoric acid with calcium hydroxide, calcium oxide, and ferrous or ferric sulfate. In principle, arsenic can be removed as a marketable product (copper arsenate for wood preservation) or as stable precipitate compounds suitable for safe landfill disposal under existing U.S. Environmental Protection Agency regulations. For more information, eontact E. Vircikova, Technical University, Faculty of Metallurgy, Letna 9, 04000 Kosice Slovakia; telephone 421-95-602-2703; fax 421-95-633-7048; e-mail vircik@hfnov.tuke.sk.     

Web-based simulation tools for the allocation of cross-border transmission rights and implementation aspects in South-East Europe

In South-East Europe (SEE), system operators (SO) started with the gradual implementation of market-based methods for the transmission capacity allocation. In this paper, the special web-based simulating software, developed for the daily explicit auction and allocation of tie-lines transmission rights on the borders of TSO-EPCG (Transmission System Operator of Montenegro), is presented as well as the monthly results achieved with its implementation. Details on the aforementioned simulator are given. After that, a small, coordinated flow-based internet simulator is created for the testing purposes, using PHP/MySQL and MATLAB as the development tools. The main advantages of the coordinated flow-based auction over the explicit NTC-based method are clearly underlined. Therefore, the proposed method can be a successful substitution for the currently applied market-based methods, and a step towards the open electricity market in SEE.     

Microwave Performance of AlGaN/GaN High-Electron-Mobility Transistors on Si/SiO2/Poly-SiC Substrates

The radiofrequency (RF) performance of AlGaN/GaN high-electron-mobility transistors (HEMTs) grown by molecular beam epitaxy (MBE) on Si-on-poly-SiC (SopSiC) substrates formed by the Smart-Cut^TM process is reported. This provides a low-cost, high-thermal-conductivity substrate for power applications. HEMTs with a 0.5 μm gate length show cutoff frequencies (f _T) of 18 to 27 GHz for gate-to-drain distances of 3 to 32 μm and a maximum frequency of oscillation (f _max) of 43 to 47 GHz. The f _max values are slightly lower than comparable devices on sapphire, SiC or Si alone. This approach looks promising for applications requiring cheap large-area substrates and better thermal management than provided by pure Si substrates alone.     

A replication framework for program‐to‐program interaction across unreliable networks and its implementation in a servlet container

We propose a service replication framework for unreliable networks. The service exhibits the same consistency guarantees about the order of execution of operation requests as its non‐replicated implementation. Such guarantees are preserved in spite of server replica failure or network failure (either between server replicas or between a client and a server replica), and irrespective of when the failure occurs. Moreover, the service guarantees that in the case when a client sends an ‘update’ request multiple times, there is no risk that the request be executed multiple times. No hypotheses about the timing retransmission policy of clients are made, e.g. the very same request might even arrive at different server replicas simultaneously. All of these features make the proposed framework particularly suitable for interaction between remote programs, a scenario that is gaining increasing importance. We discuss a prototype implementation of our replication framework based on Tomcat, a very popular Java‐based Web server. The prototype comes into two flavors: replication of HTTP client session data and replication of a counter accessed as a Web service. Copyright © 2005 John Wiley & Sons, Ltd.