نتایج جستجو برای: chemical hardness
تعداد نتایج: 401656 فیلتر نتایج به سال:
We construct an internally-consistent density-functional theory valid for noninteger electron numbers N by precise definition of a density functional that is continuous in N. In this theory, charge transfer between the atoms of a heteronuclear diatomic molecule, which have been separated adiabatically to infinity, is avoided because the hardness for fractional occupation of a single HOMO spin-o...
It has previously been observed that nail hardness increases in malnutrition [ 1,2]. In protein-calorie malnutrition this hardness could be due either to an absolute increase in mineral or to a relative increase caused by disturbances in collagen me~bolism, Ieading to a reduction in the onychogen [ 3] . Direct chemical analysis of fingernails has demonstrated an increase in the sodium and calci...
in this study, the drug atenolol on c60 fullerene were the drug and its derivatives were optimized fullerene. nbo and nmr for complex computations required in the hf/6-31g (d) and b3lyp/6-31g (d) quantum chemistry method was used. mechanical quantum calculations in theory level of b3lyp/6-31g were performed on structure of atenolol and nano fullerene atenolol with different positions of linking...
in this work, the optimization calculations were carried out on quetiapine hemifumarat, 4, and its analogues, 1-5. these calculations were carried out using the b3lyp/6-31g(d) level of theory. the dft calculations clarified a boat structure for dibenzothiazepine moiety of the molecule which piperazine moiety has a chair conformation. thermal energies (e), enthalpies (h), and free energies (g) o...
This study investigated the contamination of abraded Ti surfaces. Using a polishing machine, specimens were abraded with waterproof SiC grit papers under water cooling. The abraded surfaces were examined using element analysis, X-ray diffraction, and hardness tests. Contaminant deposits with dimensions reaching about 30 microns were observed throughout the surface. In these deposits, Ti was app...
In this research at the first, xylometazoline hydrochloride drug (XY) and its fullerene connected form (FXY) were optimized. Natural Bond Orbital (NBO) calculations for these compounds were carried out at the B3LYP/6-31G* quantum chemistry level, in the gas phase and the liquid phase. These calculations can be performed at different accuracy levels depending on the aim of the theoretical study....
The effect of deposition conditions on characteristic mechanical properties – elastic modulus and hardness – of low-temperature PECVD silicon nitrides is investigated using nanoindentation. It is found that increase in substrate temperature, increase in plasma power and decrease in chamber gas pressure all result in increases in elastic modulus and hardness. Strong correlations between the mech...
using the computational methods, the interaction effect of glutamine amino acid on graphene was investigated. for this purpose, the density functional theory) dft (in the ground state of 6-31g was used, and the interaction effects of glutamine on graphene was investigated through attachment to two different base positions. different parameters such as energy levels, the amount of chemical shif...
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 hardness profile as a tool to detect spurious stationary points in the potential energy surface.
In the present work, we have computed the energy and hardness profiles for a series of inter and intramolecular conformational changes at several levels of calculation. All processes studied have in common the fact that the choice of a weak methodology or a poor basis set results in the presence of spurious stationary points in the energy profile. At variance with the energy profiles, the hardn...
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