alumina is one of the most widely used ceramic materials as catalysts, catalyst supports and absorbents, and also wear resistant coating. this study focused on fabricating and characterizing of alumina ceramic nanoparticles fabricated using new and simple sol-gel method. aluminium oxide (al2o3) nanoparticles were synthesized by iron (iii) nitrate 9-hydrate as precursor. physicochemical properti...

A new light is thrown on the Portnoff [1] speech signal timescale modification algorithm. It is shown in particular that the Portnoff algorithm easily accommodates expansion factors bigger than 2 without causing reverberation nor chorusing. The modified Portnoff algorithm, which draws on spectral modification techniques due to Seneff [2], has been tested on several speech signals. The quality o...

according to the bronsted definition, any compound which has a hydrogen atom is an acid, since itmay be lost as a proton. a thermodynamical cycle is proposed to calculate absolute pka values forbronsted acids in aqueous solution. the equilibrium of dissociation of a bronsted acid depends onthe interaction of the acid and its conjugate base with solvent molecules. there fore the pka valuedepends...

The present paper describes the phase only pattern synthesis for the active phased array antenna using genetic algorithm. The phase only synthesis is required to broaden and shape the beam in transmit mode of operation where all elements are fed through the saturated power of transmit/receive modules (TRM). This technique is very useful in multifunctional radar application where broadened beam ...

Nanostructured films and coatings with controlled surface area, porosity, crystalline orientation, grain sizes, and crystal morphologies are desirable for many applications, including microelectronic devices, chemical and biological sensing and diagnosis, energy conversion and storage (photovoltaic cells, batteries and capacitors, and hydrogen-storage devices), lightemitting displays, catalysis...

As an incommensurate epitaxy, van der Waals epitaxy allows defect-free crystals to grow on substrates even with a large lattice mismatch. Furthermore, van der Waals epitaxy is proposed as a universal platform where heteroepitaxy can be achieved irrespective of the nature of the overlayer material and the method of crystallization. Here we demonstrate van der Waals epitaxy in solution phase synt...

The rapid growth of multiple parallel synthesis in our laboratories has created a demand for a robust, easily accessed automated system for solution-phase reaction work-up, since the manual work-up of large numbers of small-scale reactions is both time-consuming and tedious, and is a rate limiting step in the generation of large numbers of compounds for test. Work-up in chemical organic synthes...

in this research work the solid-solutions of (bi2o3)1-x (co2o3)x, [x= 0.05, 0.1] (1), (bi2o3)1-x (ho2o3) x, [x= 0.025, 0.05] (2), and (bi2o3)1-x-y (co2o3)x (ho2o3)y, [x=0.05] ; [y= 0.01, 0.02] (3) have been synthesized  using sol-gel method. the effects of transition metal oxides doping on the crystallization and phase transition of the bi2o3 were discussed by x-ray diffraction (xrd). the xrd p...

We report the synthesis and characterization of axial nanorod heterostructures composed of cadmium selenide (CdSe) and cadmium sulfide (CdS). The synthesis employs a solution-liquid-solid (SLS) mechanism with the assistance of bismuth nanocrystals adhered to a substrate (silicon or a III-V semiconductor). Transmission electron microscopy (TEM) and diffraction studies show that CdSe and CdS segm...