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111.
Mohammad Z. Kassaee Foad Buazar Seyed M. Musavi Elaheh Motamedi 《Monatshefte für Chemie / Chemical Monthly》2007,138(9):833-848
Summary. Heavier atom containing X
2SiC2, and X
2GeC2 cyclopropenylidenes transform into new silylenes, germylenes, and carbenogermylenes at DFT and ab initio levels (X = H, CN, NH2, and OMe). The number of transformations or rearrangements appear roughly proportional to the covalent radii of the group 14 elements
(Ge > Si > C). 相似文献
112.
Ionic liquids such as 1,3-dialkylimidazolium bromides make excellent catalysts and solvents for N-alkylation of amino-9,10-anthraquinones in the presence of trialkyl phosphites. For triethyl phosphite, [bpim][Br] gave better results. The ionic liquids are successfully regenerated and reused. 相似文献
113.
Synthesis of ZnO nanostructures with controlled morphology and size in ionic liquids 总被引:1,自引:0,他引:1
Issa Yavari Ali R. Mahjoub Elaheh Kowsari Maryam Movahedi 《Journal of nanoparticle research》2009,11(4):861-868
Nanostructured ZnO has been synthesized by a hydrothermal route, using different ionic liquids (ILs) as the morphology templates.
The morphology of ZnO changes from rod-like to star-like and flower-like in different ILs. A 3D nano/micro structure ZnO with
unique flower-like morphology has been synthesized via the assembly of dicationic IL and [Zn(OH)4]2−. The flower-like pattern was obtained in the presence of IL 1. The flower-like ZnO structure has a hexagonal prism, with a hexagonal pyramid on the tip, and diameter of ~444 nm. While
the ZnO prepared in IL 2, shows uniform rod-like shape with a diameter of 91 nm, star-like morphology consisting of nanorods with diameter of ~109 nm
was formed in IL 3. The XRD, SEM, and PL spectra have been employed for characterization of the synthesized ZnO nano structures. 相似文献
114.
Zahra Dehghani Firouzabadi Ali Mohammad Haji Shabani Mohammad Hassan Ehrampoush Elaheh Nourbala Tafti 《International journal of environmental analytical chemistry》2018,98(6):555-569
A novel magnetic dispersive solid phase extraction method using magnetic multi-walled carbon nanotubes modified with 5-mercapto-3-phenyl-1,3,4-thiadiazole-2-thione potassium salt (bismuthiol II) (MMWCNTs@Bis) as the sorbent was developed for the separation and preconcentration of inorganic selenium (IV) prior to its determination by electrothermal atomic absorption spectrometry. The prepared MMWCNTs@Bis sorbent was characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and X-ray diffraction. Total selenium was determined after reduction of Se(VI) to Se(IV) by addition of hydrochloric acid and heating the mixture in a boiling water bath. Se(VI) concentration was determined from the difference between the amounts of total selenium and Se(IV). Under the optimised experimental conditions, an enhancement factor of 196 and a detection limit (based on 3Sb/m) of 0.003 µg L?1 was obtained for aqueous samples. The relative standard deviation at 0.1 µg L?1 concentration level of Se(IV) (n = 6) was found to be 5.2 and 7.7% for intra- and inter-day analysis, respectively. The method was successfully applied to the determination of inorganic selenium species in water and total selenium in food samples. 相似文献
115.
Elaheh Neshat Rahim Khoshbakhti Saray 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2019,25(2):167-194
The main purpose of the current study is mathematical modelling and validation of mass transfer phenomenon in homogeneous charge compression ignition engines. A validated multi-zone model coupled to a semi-detailed chemical kinetics is used to predict homogeneous charge compression ignition combustion and emissions. Heat and Mass transfer submodels are linked to the multi-zone model. Bulk flow and diffusion mass transfer between zones are considered. The results indicate that the diffusion mass transfer is negligible in homogeneous charge compression ignition engines. Bulk flow mass transfer plays a critical role in homogeneous charge compression ignition simulation and applying it in the multi-zone model leads to accurate prediction of the start of combustion, peak pressure and exhaust emissions. The results show that the maximum error changes from 90% to 5% in carbon monoxide prediction and from 98% to 14% in unburned hydrocarbons prediction, using the mass transfer submodel. 相似文献
116.
Elaheh Molaakbari Dariush Afzali 《International journal of environmental analytical chemistry》2013,93(4):365-376
A solid phase extraction method for simultaneous preconcentration and separation of trace amounts of copper, cobalt and silver in different samples, using a column packed with modified Amberlyst®15 resin is developed. Amberlyst®15 resin was modified with 5-(4-dimethylaminobenzylidene)rhodanine and then the modified resin was used as a support material for the solid phase extraction and preconcentration of Cu(II), Co(II) and Ag(I) ions from aqueous solution in the pH range 3.5–4.5. The adsorbed metal ions on the column were quantitatively eluted with a 7% thiourea solution prepared in 2?mol?L?1 HNO3, which were detected by flame atomic absorption spectrometry. The effects of analytical parameters including pH of the solution, eluent type, flow rate of samples, eluent and matrix ions were investigated for optimization of the presented procedure. The detection limits were 2.1, 0.9 and 0.9?ng?mL?1 for Cu(II), Co(II) and Ag(I) ions, respectively based on the three times the standard deviations of the blanks. The preconcentration factor was 112.5. The calibration graphs were obtained in the ranges of 0.05 to 10.0, 0.03 to 13.0 and 0.04 to 9.0?µg?mL?1 for Cu(II), Co(II) and Ag(I) ions concentrations, respectively. Relative standard deviations (n?=?7) for Cu(II), Co(II) and Ag(I) ions were found ±2.5 %, ±0.84% and ±3.8% respectively. The method was applied to the determination of mentioned ions in well water, waste water and lettuce sample. 相似文献
117.
Reza Ghiasi Elaheh Amini 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(10):1684-1691
The electronic structure and properties of the iridathiabenzene and iridaoxabenzene isomers have been investigated using the hybrid density functional mpw1pw91 theory. The energetic aspect shows that trans-ortho-isomer is the most stable isomer. This is compatible with principles of minimum energy and minimum polarizability. Molecular orbital analysis shows a linear correlation between hardness and anisotropic polarizability values for Iridathiabenzene and iridaoxabenzene isomers. The structural and natural bond analysis (NBO) results illustrate electronic delocalization in these rings. Also, the study of non linear optical properties of these molecules indicate a good correlation between βtot and E(HOMO) for iridathiabenzene. The results from natural bond orbital (NBO) analysis have provided insights into Ir—ligand, P—Hapical and P—Hbasal bonding. 相似文献
118.
N2O4 was easily impregnated on polyethyleneglycol to give a stable reagent. The polyethyleneglycol-N2O4 (PEG-N2O4) system was used as an effective nitrating agent for the nitration of phenols. Mono- and dinitrophenols can be obtained via direct nitration of phenols in the presence of PEG-N2O4 at room temperature in moderate to high yields. 相似文献
119.
Razieh Sanavi Khoshnood Elaheh Hatami 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(13):2294-2299
The complex formation between 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (Kryptofix-5) and Sn2+ ions was studied in pure acetonitrile (AN), dimethylformamide (DMF), 1,4-dioxane (DOX), and methanol (MeOH) and in acetonitrile-1,4-dioxane (AN-DOX), acetonitrile-dichloromethane (AN-DCM), acetonitrile-methanol (AN-MeOH), and acetonitrile-dimethylformamide (AN-DMF) binary mixed solvent solutions at different temperatures using conductometric method. 1: 1 [ML] complex is formed between the metal cation and ligand in most solvent systems but in the cases of AN-MeOH (MeOH = 90 mol %) binary mixture and in pure MeOH a 2: 1 [M2L] complex was observed, that is the stoichiometry of complexes may be changed by the nature of the medium. The stability order of the (Kryptofix-5·Sn)2+ complex in the studied binary mixed solvent solutions at 25°C was found to be AN-DOX > AN-DCM > AN-MeOH > AN-DMF and in the case of pure solvents at 25°C the sequence was the following: AN > DMF > DOX. A non-linear behavior was observed for changes of logK f of (Kryptofix-5·Sn)2+ complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent intractions and also by the preferential solvation of the f species involved in the complexation reaction. The values of standard enthalpy changes (ΔH c ○ ) for complexation reactions were obtained from the slope of the Van’t Hoff plots and the changes in standard entropy (ΔS c ○ ) were calculated from the relationship ΔG c, 298.15 ○ = ΔH c ○ ? 298.15ΔS c ○ . The results show that in most cases, the (Kryptofix-5·Sn)2+ complex is both enthalpy and entropy stabilized. 相似文献
120.
New regularities and an equation of state for liquids 总被引:1,自引:0,他引:1
Three regularities have been introduced for liquids (T < TC and ρ > ρC) based on average potential energy. The experimental data have been used to show the validity of the regularities. First, there exists near-linearity relation between and ρ for all isotherms of a liquid, where Pi and ρ are internal pressure and density, respectively. Second, changes linearly with ρ for each isotherm of any liquid, where Z and Vm are compressibility factor and molar volume, respectively. Third, a new regularity using the definition of bulk modulus and our new equation of state between reduced bulk modulus and density has been introduced, that is versus ρ must be linear for all isotherms of a liquid where Br is the reduced bulk modulus.
A new equation of state has been also derived. The density of some liquids in the extensive ranges of temperature and pressure has been calculated using the new equation of state. The densities calculated from this equation agree with experiment to better than 0.3%. The new equation of state can predict internal pressure, thermal expansion coefficient, and isothermal compressibility of liquids within experimental error. 相似文献