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101.
This work introduces a version of filter technique to produce an adaptive radius and then adds it into trust-region algorithm. This method uses advantages of the functions norm’s necessary information in order to produce a smaller radius of trust-region close to the optimizer and also a larger radius of trust-region far away from the optimizer using advantages of the filter technique (Fatemi and Mahdavi-Amiri, Comput. Optim. Appl. 52(1), 239–266 2012). Under some ordinary conditions, the global convergence of the proposed approach is proved. Numerical results are also presented. 相似文献
102.
Construction of Modified Carbon Paste Electrode for Highly Sensitive Simultaneous Electrochemical Determination of Trace Amounts of Copper (II) and Cadmium (II)
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Abbas Afkhami Morteza Soltani‐Shahrivar Hamed Ghaedi Tayyebeh Madrakian 《Electroanalysis》2016,28(2):296-303
A chemically modified electrode was constructed for rapid, simple, accurate, selective and highly sensitive simultaneous determination of Cu(II) and Cd(II) using square wave anodic stripping voltammetry. The electrode was prepared by incorporation of SiO2 nanoparticles, coated with a newly synthesized Schiff base, in carbon paste electrode. The limit of detection was found to be 0.28 ng mL?1 and 0.54 ng mL?1 for Cu(II) and Cd(II), respectively. The proposed chemically modified electrode was used for the determination of copper and cadmium in several foodstuffs and water samples. 相似文献
103.
Abdol Reza Hajipour Morteza Karimzadeh Sirous Ghorbani Hossein Farrokhpour Alireza Najafi Chermahini 《Structural chemistry》2016,27(5):1345-1362
Electronic structures of allophanic acid were studied using MP2/6-311++G(d,p) level of theory. Five most stable tautomers were selected and stability of them was studied in detail. Obtained data showed that tautomer 1 having hydrogen atom in the central nitrogen N3 and also in a trans conformation of carbonyl and amino functional groups becomes the most stable one. Then, interconversion of these tautomers to each other was investigated step by step through internal rotation and proton transfer routes. Results indicated that movement of protons determines rate-determining step of all paths A–E. Effects of different solvents were carefully surveyed for each tautomer, and among investigated solvents, water made slight stabilization. Activation barrier for proton exchange assisted by one water molecule and one formic acid molecule was also studied, separately. Both molecules had a great influence on lowering barrier especially for proton transfer routes. Comparative MP2 study showed that the barrier will be lowered much more when acid-assisted proton exchange takes place. 相似文献
104.
Morteza?MoradiEmail author Ali?Aghakhani Mohammad?Javad?Eshraghi 《Structural chemistry》2016,27(2):535-542
Electrical sensitivity of a boron carbon nanotube (B2CNT) was examined toward carbon monoxide (CO) molecule by using dispersion-corrected density functional theory calculations. It was found that CO is weakly adsorbed on the tube, releasing energy of 3.5–4.1 kcal/mol, and electronic properties of the tube are not significantly changed. To overcome this problem, boron and carbon atoms of the tube were substituted by aluminum and silicon atoms, respectively. Although both Al and Si doping make the tube more reactive and sensitive to CO, Si doping seems to be a better strategy to manufacture CO chemical sensors due to the higher sensitivity without deformation of nanotube structure after adsorption procedure. Moreover, it was shown that some interference molecules such as H2O, H2S and NH3 cannot significantly change the electronic properties of B2CNT. Therefore, the Si-doped tube might convert the presence of CO molecules to electrical signal. 相似文献
105.
Kazem Barati William Clegg Mohammad Hossein Habibi Ross W. Harrington Arash Lalegani Morteza Montazerozohori 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(3):239-242
Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff base N,N′‐bis(trans‐2‐nitrocinnamaldehyde)ethylenediamine {Nca2en, systematic name: (1E,1′E,2E,2′E)‐N,N′‐(ethane‐1,2‐diyl)bis[3‐(2‐nitrophenyl)prop‐2‐en‐1‐imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ‐chlorido‐μ‐hydroxido‐bis(chlorido{(1E,1′E,2E,2′E)‐N,N′‐(ethane‐1,2‐diyl)bis[3‐(2‐nitrophenyl)prop‐2‐en‐1‐imine]‐κ2N,N′}copper(II)) dichloromethane sesquisolvate, [Cu2Cl3(OH)(C20H18N4O4)2]·1.5CH2Cl2. The dinuclear complex has a folded four‐membered ring in an unsymmetrical Cu2OCl3 core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two CuII atoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca2en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five‐coordinate complex, of the Nca2en Schiff base ligand. Molecules of the dimer are associated in pairs by ring‐stacking interactions supported by C—H…Cl interactions with solvent molecules; a further ring‐stacking interaction exists between the two Schiff base ligands of each molecule. 相似文献
106.
Morteza Hosseini Freshteh Khaki Ehsan Shokri Hossein Khabbaz Mehdi Dadmehr Mohammad Reza Ganjali Mina Feizabadi Davood Ajloo 《Journal of fluorescence》2017,27(6):2059-2068
A novel sensitive method for detection of DNA methylation was developed with thioglycollic acid (TGA)-capped CdTe quantum dots (QDs) as fluorescence probes. Recognition of methylated DNA sites would be useful strategy due to the important roles of methylation in disease occurrence and developmental processes. DNA methylation occurs most often at cytosine-guanine sites (CpG dinucleotides) of gene promoters. The QDs significantly interacted with hybridized unmethylated and methylated DNA. The interaction of CpG rich methylated and unmethylated DNA hybrid with quantum dots as an optical probe has been investigated by fluorescence spectroscopy and electrophoresis assay. The fluorescence intensity of QDs was highly dependent to unmethylated and methylated DNA. Specific site of CpG islands of Adenomatous polyposis coli (APC), a well-studied tumor suppressor gene, was used as the detection target. Under optimum conditions, upon the addition of unmethylated dsDNA, the fluorescence intensity increased in linear range from 1.0?×?10??10 to 1.0?×?10??6M with detection limit of 6.2?×?10??11 M and on the other hand, the intensity of QDs showed no changes with addition of methylated dsDNA. We also demonstrated that the unmethylated and methylated DNA and QDs complexes showed different mobility in electrophoresis assay. This easy and reliable method could distinguish between methylated and unmethylated DNA sequences. 相似文献
107.
Ali Ramazani Amir Tofangchi Mahyari Morteza Rouhani Aram Rezaei 《Tetrahedron letters》2009,50(40):5625-5627
Reaction of an isocyanide with an iminium ion intermediate, formed by reaction between an electron-poor 2-hydroxybenzaldehyde derivative and a secondary amine in the presence of silica gel proceeds smoothly at room temperature to afford benzo[b]furan derivatives in high yields. 相似文献
108.
Farough Nasiri Morteza Bidar Bahareh Atashkar 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):463-466
Abstract The reaction between dibenzoylacetylene and enol systems, such as acetylaceton or cyclohexane-1,3-dione in the presence of
triphenylphosphine in THF/H2O, leads to 4-acetyl-3-benzoyl-1-phenyl-1,5-hexanedione and 2-hydroxy-3-(2-oxo-2-phenylethyl)-2-phenyl-3,5,6,7-tetrahydro-1-benzofuran-4(2H)-one. Subsequently, these compounds undergo cyclization and elemination reactions in acidic dichloromethane at room temperature
to produce known highly functionalized furan derivatives.
Graphical abstract
相似文献
109.
A novel micellar selectivity triangle (MST) is developed and used to characterize and classify the chemical selectivities of pseudo-phases in electrokinetic chromatography (EKC). The MST scheme is, in concept, similar to the widely known solvent selectivity triangle (SST) originally developed by Snyder. However, the MST is based on linear solvation energy relationships. Thus it incorporates the solvation characteristics of both the pseudo-phase and the bulk solvent; while the SST is basically for classification of pure solvents. The similarities and differences of these pseudo-phases are determined by the relative scales of hydrogen bond donating ability (Xb), hydrogen bond accepting ability (Xa) and dipolarity (Xs). The MST scheme is used for characterization and classification of a wide range of pseudo-phases such as micelles, polymers, vesicles, liposomes, as well as mixed systems such as mixed micelles, mixed polymer–surfactants, organically modified pseudo-phases, etc. Over seventy pseudo-phases were examined and four clusters of pseudo-phases with different selectivity patterns are recognized that include pseudo-phases with strong hydrogen bond acidities (e.g. fluorinated micelles or micelles modified with fluorinated alcohols), strong hydrogen bond acceptor pseudo-phases (such as bile salts, liposomes, microemulsions, as well as biphasic octanol–water system), strong dipolar phase of a class of polymeric pseudo-phase, and pseudo-phases with intermediate hydrogen bonding and dipolarity [like sodium dodecyl sulfate (SDS) and its analogs as well as organically modified SDS]. The MST scheme is also useful in identifying pseudo-phases that closely resemble the selectivities of octanol–water for determination of octanol–water partition coefficients by EKC. 相似文献
110.
Babak Mokhtarani Ali Sharifi Hamid Reza Mortaheb Mojtaba Mirzaei Morteza Mafi Fatemeh Sadeghian 《The Journal of chemical thermodynamics》2009,41(12):1432-1438
Densities and viscosities of 1-butyl-3-methylimidazolium nitrate [Bmim][NO3], and its binaries with alcohol (ethanol, 1-propanol, or 1-butanol) were measured at different temperatures. The densities and viscosities of pure ionic liquid were correlated successfully by empirical equations. The Vogel–Fulcher–Tammann equations can fit the experimental data of viscosities for pure IL. Excess molar volume and viscosity deviations were calculated for the binaries. The excess molar volumes have negative deviations from the ideal solution. 相似文献