نتایج جستجو برای: solvent method
تعداد نتایج: 1673148 فیلتر نتایج به سال:
Integral equation theory is used for extrapolating free energy data from molecular simulations of a reference state with respect to a modification of the interaction potential. The methodology is applied to the correction of artefacts arising from potential shifting and truncation. Corrective contributions for the hydration free energy with respect to the full potential are analysed for the cas...
Cadmium sulfide nanoparticles were grown using wet chemical method by dissolving the reactants of cadmium acetate and sodium sulfide in the presence of thioglycerol (TG) as capping agent in ethanol solvent. Different nanoparticle sizes and size distribution were obtained through varying the molarities of thioglycerol. At higher TG concentration, synthesis provides a nearly monodisperse nanopart...
A facile and efficient method for the preparation of 1,1-diacetates of aldehydes is improved. The acidified kaolin with sulfuric acid (2 % w/w) catalyzed 1,1-diacetates formation from aldehydes in solvent-free conditions. Both aromatic and aliphatic aldehydes gave high yields (85-95 %) of the corresponding 1, 1-diacetates. Advantages of this method are the use of inexpensive and selective catal...
Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-flame ionization detection (GC-FID) was applied for the determination of two tricyclic antidepressant drugs (TCAs), amitriptyline and nortriptyline, from water samples. This method is a very simple and rapid method for the extraction and preconcentration of these drugs from environmental sample solutions. In this m...
abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...
We have developed a high performance liquid chromatography (HPLC) method to separate lecithin from other phospholipid classes and to obtain lecithin from biologic materials. The separation was performed on a preparative 10-micron Spherisorb column with an optimized solvent system consisting of the following components: acetonitrile, isopropanol, methanol, water, and trifluoroacetic acid. The ad...
This work presented determination of some polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene and acenaphthene in biological samples by Dispersive Liquid-Liguid Microextraction (DLLME) and gas chromatography. In this method, the appropriate mixture of extraction solvent (dichloromethane) and disperser solvent (acetone) are injected rapidly into the aqueous sample by syringe. Ther...
Dispersive liquid-liquid microextraction (DLLME) coupled with high-performance liquid chromatography-variable wavelength detector (HPLC-VWD) was developed for extraction and determination of thiamphenicol (THA) in honey. A mixture of extraction solvent (30 microL 1,1,2,2-tetrachloroethane) and dispersive solvent (1.0 mL of acetonitrile) was rapidly injected into 5.00 mL sample solution for the ...
The classical Soxhlet method provides the fundamental basis for a modern-day solvent extraction system, the SoxtecTM. Using the Randall modification, sometimes called the submersion method, the Soxtec provides a faster approach to solvent extraction for the gravimetric quantitation of fat and oil. Typically, the Soxtec methods require only 20–25% of the time required for traditional Soxhlet ext...
This article attempts to increase the prediction accuracy of residue solvent accessibility and real-value backbone torsion angles of proteins through improved learning. Most methods developed for improving the backpropagation algorithm of artificial neural networks are limited to small neural networks. Here, we introduce a guided-learning method suitable for networks of any size. The method emp...
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