نتایج جستجو برای: solvent system
تعداد نتایج: 2278530 فیلتر نتایج به سال:
The most important part of the membrane synthesis process so that it has desired pores is solidification membrane, begins with a change from one liquid phase into two phases (liquid-liquid demixing). At certain period during demixing, polymer-rich solidifies; thus, dense matrix formed. Parameters determine mechanism formation are based on thermodynamics including separation Solvent-Polymer-Non-...
a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...
TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reused several t...
In many M.D. simulations the simulated system consists of a single macromolecule in a solvent. Usually, one is not interested in the behaviour of the solvent, so, the CPU time may be minimized by minimizing the amount of solvent. For a given molecule and cut-off radius this may be done by constructing a computational box with near minimal volume. In this article a method is presented to constru...
A new microencapsulation technique that utilizes interfacial mass transfer between two mutually soluble liquids has been developed. The technique is based on formation of a solid polymer film at the interface of a solution of a water-insoluble polymer and an aqueous solution, resulting from the mutual mass transfer of solvents (i.e., solvent exchange). Reservoir-type microcapsules were prepared...
TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reused several t...
TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reuse...
a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...
The absorption spectra of aminocoumarin C151 in water and n-hexane solution are investigated by an explicit quantum chemical solvent model. We improved the efficiency of the frozen-density embedding scheme, as used in a former study on solvatochromism (J. Chem. Phys. 2005, 122, 094115) to describe very large solvent shells. The computer time used in this new implementation scales approximately ...
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