نتایج جستجو برای: aqueousorganic phase ratio
تعداد نتایج: 1068828 فیلتر نتایج به سال:
In this study, extraction of tannic acid using microchannel was investigated. Affective parameters were optimized. Different solvents including buthanol, ethylacetate and n-hexane as organic phase, methanol, propanol, ethanol and water as aqueous phase investigated. Microchannels with different confluence angles and diameters were examined. Microchannels with different confluence angles and dia...
In this research zinc oxide particles prepared by solution combustion synthesis using zinc nitrate as oxidant and citric acid as fuel. The effect of citric acid to oxidant ratio (0.5, 1, 2 and 3) on phase formation, microstructure, optical properties and photocatalytic performance of the powders were studied using XRD, SEM and DRS techniques. Single phase ZnO particles by wurtzite structure was...
the purpose of this study was to examine the english language needs of medical students at tehran university of medical sciences . analysis of the needs took place for three groups: 320 undergraduate students, 30 postgraduate students and 20 university instructors. a triangulation approach to collect data was used in which a combination of the quantitative (using the questionnaires) and qualita...
BACKGROUND There is a consensus that administration of progesterone to women after IVF for luteal phase support (LPS) is associated with a higher ongoing pregnancy rate. However there are few studies, including only one randomized study, which have examined the optimal duration of LPS. METHODS A questionnaire concerning details of LPS was returned from 21 leading IVF centres. We then randomiz...
Introduction It has been shown that the combined use of complex valued in-phase (ip) and opposed-phase (op) images can improve the signal to noise ratio (SNR) of dynamic MR mammography (MRM)[1] compared to conventional ip-subtraction (SIPCN). While improved SNR is certainly helpful, this study is comparing the overall image quality and especially the lesion sharpness of four different contrasts...
Objective(s): The aim of this work was to investigate the effect of the natural and the chemically modified form of cyclodextrins namely; β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) respectively on the solubility and dissolution rate of aripiprazole; an antipsychotic medication showing poor aqueous solubility. Materials and Methods: Phase solubility of ar...
the aim of this paper is to minimize output phase noise for the pure signal synthesis in the frequency synthesizers. for this purpose, first, an exact mathematical model of phase locked loop (pll) based frequency synthesizer is described and analyzed. then, an exact closed-form formula in terms of synthesizer bandwidth and total output phase noise is extracted. based on this formula, the phase ...
Using molecular dynamics simulation with an angle-dependent Lennard-Jones potential, we study orientational glass with quadrupolar symmetry in mixtures of elliptic particles and circular impurities in two dimensions. With a mild aspect ratio (= 1.23) and a mild size ratio (= 1.2), we realize a plastic crystal at relatively high temperature T. With further lowering T, we find a structural phase ...
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