نتایج جستجو برای: taft
تعداد نتایج: 465 فیلتر نتایج به سال:
Due to the dryness of the weather in most parts of Iran and the lack of sufficient rainfall in more than six months of the year in most places, resulting in the seasonality of rivers and the lack of access to water, various arrangements for fresh water supply in the dry seasons has been established. The construction of the AB ANBAR (water reservoir and cistern) is one of innovative ways to supp...
In this study, four arylazobenzylidene dyes (a-d) were synthesized with excellent yields in two steps using Knoevenagel condensation and azo-coupling reactions. Absorption spectra of these dyes with different substituents were investigated in organic solvents as a function of solvent polarity. The spectral features of synthesized arylazobenzylidene dyes were described according to azo-hydrazone...
The protonation constants of alanine and alanine methyl ester were determined in different aqueous solutions of 1,4-dioxane containing (0-50% v/v), using a potentiometric method at 25o C and constant ionic strength 0.1 mol.L-1 (NaCl). The protonation constants were analyzed in terms of Kamlet, Abboud and Taft (KAT) parameters. The results show that the effect of β is higher in comparison with t...
A series of five tetracyclic mono azo dyes based on the diazotization 1-amino-8-hydroxynaphthalene-3,6-disulphonic acid and subsequent coupling with substituted (un)sulphonated naphthalene derivatives have been synthesized. The chemical structures were established using UV–visible, IR, NMR as well mass spectrometry. Based number sulphonic other hydrophilic groups they contain, compounds showed ...
درمنه (artemisia)، از مهمترین گیاهان بوته ای در جوامع گیاهی طبیعی است. این گیاه به دلیل داشتن ترکیبات دارویی و اسانس های معطر دارای ارزش اقتصادی زیادی در جذب ارز کلان برای کشور می باشد. در این مطالعه، دو آزمایش انجام شد در آزمایش اول تنوع ژنتیکی تعداد 19 ژنوتیپ درمنه متعلق به 4 گونه artemisia با استفاده از 40 آغازگر 10 نوکلئوتیدی rapd مورد بررسی قرار گرفت. که فقط، 15 آغازگر چند شکلی را بین ژنوت...
These and other letters, including a letter from Dr L. I. Taft reporting on the first brain the Walter and Eliza Hall Institute (WEHI) received, are not included in the published Gajdusek correspondence of the early days. On 4th February, John Gunther sent another letter to Gray Anderson in which he wrote, ‘The Government Anthropologist has visited Fore and informs me the Administration is losi...
Linear free energy relationships (LFER) were applied to the IR, Hand C-NMR spectral data of N-(substituted phenyl)-2-cyanoacetamides. A variety of substituents were employed for phenyl substitution and fairly good correlations were obtained using the simple Hammett and the Hammett–Taft dual substituent parameter equations. The correlation results of the substituent induced C-NMR chemical shifts...
Deoxycytidine was reacted with four epoxides of varying alkylating rates: propylene oxide, glycidol, epichlorohydrin and trichloropropylene oxide. Deoxycytidine was chosen to compare the reactivities of these epoxides as all sites of possible alkylation, the oxygen and both nitrogens, are involved in base pairing in DNA. Reaction products were separated on HPLC. Products of the least and most r...
The polarities of a wide range of ionic liquids have been determined using the Kamlet-Taft empirical polarity scales α, β and π*, with the dye set Reichardt's Dye, N,N-diethyl-4-nitroaniline and 4-nitroaniline. These have been compared to measurements of these parameters with different dye sets and to different polarity scales. The results emphasise the importance of recognising the role that t...
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