نتایج جستجو برای: and 29si chemical shift
تعداد نتایج: 16882937 فیلتر نتایج به سال:
influence of aluminum, gallium, indium- doping on the boron-nitride nanotubes (bnnts) investigated with density functional theory (dft) and hartreefock (hf) methods. for this purpose, the chemical shift of difference atomic nucleus was studied using the gauge included atomic orbital (giao) approch. in the following, structural parameter values, electrostatic potential, thermodynamic parameters,...
abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...
there is no doubt that human being needs to become integrated with industry and industry needs to be progressed, daily. on the other hand, serious events in industrial units specially in oil industries has been shown that such damages and events are industry related ones. the consequence of such events and damages which resulted in chemical and poisoned explosions and loss of life and property ...
Disproportionation reactions of chlorosilane compounds in the presence boron trichloride yield compound H[B(SiCl3)4]. Spectroscopic analyses yellow-whitish solid with IR-, Raman-, and NMR-spectroscopy (29Si, 11B) show a highly symmetric anion containing boron, which is fourfold coordinated silicon. Due to high symmetry 1J(11B,29Si) even 1J (10B, 29Si) couplings can be observed NMR spectra disso...
~3C and 295i nuclear magnetic resonance spectroscopy with magic-angle spinning bas been used to study the short-range ordering and bonding in the structures of intercalates of kaolinite with formamide, hydrazine, dimethyl sulfoxide (DMSO), and pyridine-N-oxide (PNO). The 29Si chemical shift indicated decreasing levels of bonding interaction between the silicate layer and the intercalate in the ...
in this research at the first metoprolol drug and its fullerene derivative were optimized. natural bond orbital (nbo), nuclear indepndent chemical shift (nics) and finally ir calculations, for these compounds were carried out at the b3lyp/6-31g* quantum chemistry level. different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of homo/lumo, chemical...
the n-(2-benzoyl-phenyl) oxalyl derivatives are important models for studying of three-centered intramolecular hydrogen bonding in organic molecules. the quantum theoretical calculations for two crystal structures of n-(2-benzoyl-phenyl) oxalyl (compounds i and ii) were performed by density functional theory (b3lyp method and 6-311+g* basis set). from the optimized structures, geometric paramet...
Sulforaphane, an isothiocyanate found in broccoli and other cruciferous vegetables. it is an antioxidantand anti-cancer agent, and reduces blood pressure, and also has anti-allergic Effects.In this article, six theoretical methods have been used for calculation of physical parameters insolforaphane and several similar compounds. We calculated physical parameters like atomic charges.energy (AE) ...
abstract the influence of cation?? and anion?? interactions on the strength and nature of n…h hydrogen bond has been investigated by quantum chemical calculations in s-triazine…3hf complex. ab initio calculations were performed at mp2/6-311++g(d,p) level of theory. the natural bond orbital (nbo) analysis and the bader’s quantum theory of atoms in molecules (aim) were also used to elucidate t...
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