排序方式: 共有155条查询结果,搜索用时 15 毫秒
61.
Firouz Matloubi Moghaddam Seyedeh Maryam DokhtTaimoory Hossein Ismaili Ghasem Rezanejade Bardajee 《合成通讯》2013,43(23):3599-3607
KF/Al2O3 efficiently catalyzes N‐alkylation of heterocyclic, primary, and secondary amines and S‐alkylation of thiols with a variety of alkyl halides. The N‐alkylation and S‐alkylation adducts were produced in good to excellent yields and in short times. 相似文献
62.
Shapour Heidarkhani Ghasem A. Afrouzi Massimiliano Ferrara Shahin Moradi 《复变函数与椭圆型方程》2016,61(7):931-968
In this paper, we study the existence of multiple solutions for impulsive fourth-order differential equations of Kirchhoff type. Using a variational method and some critical points theorems, we obtain some new criteria for guaranteeing that impulsive fourth-order differential equations of Kirchhoff type have three and infinitely many solutions. Some recent results are extended and improved. Some examples are presented to demonstrate the applications of our main results. 相似文献
63.
Masoud Saffarzadeh Mohammad Heydari Ghasem Barid Loghmani 《Mathematical Methods in the Applied Sciences》2020,43(8):5212-5233
In this paper, an efficient and accurate numerical iterative algorithm based on the linear spline interpolation for solving the system of nonlinear stochastic Itô-Volterra integral equations is presented. The most important merit of this method is that it does not need to solve any system of nonlinear algebraic equations. An upper bound for the linear spline approximation of the stochastic function is provided. Using this upper bound and under the Lipschitz and linear growth conditions, the convergence analysis of the suggested method is studied. Finally, to verify the efficiency of the proposed scheme, some problems in the finance, physics, and biology are investigated, and the obtained results are compared with the stochastic -method. 相似文献
64.
Javad Zolgharnein Ghasem Shahmoradi Saeid Amani 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):163-167
The complexation reaction of phenylaza-15-crwon-5, 4- nitrobenzo- 15-crown-5, and benzo-15-crown-5 with Ag+, Tl+ and Pb2+ ions in methanol solution have been studied by a competitive potentiometric method. The Ag+/Ag electrode used both as an indicator and reference electrode in a concentration cell. The emf of cell monitored as the
crown ethers concentration varies through the titration. The stoichiometry and stability constants of resulting complexes
have been evaluated by MINIQUAD. The stoichiometry for all resulting complexes was 1:1. The stability of these metal ions
with derivatives of 15-crown-5 are in order phenylaza-15-crown-5 > Benzo-15-crown-5 > 4-nitrobenzo-15-crown-5, and for the
each used crown ethers are as Pb2+ > Ag+ > Tl+. The effect of the substituted group on the stability of resulting complexes was considered. The obtained results are novel
and interesting. 相似文献
65.
Gold nanoparticle (Au‐NPs)‐Titanium oxide nanotube (TiO2‐NTs) electrodes are prepared by using galvanic deposition of gold nanoparticles on TiO2‐NTs electrodes as support. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy results indicate that nanotubular TiO2 layers consist of individual tubes of about 60–90 nm diameters and gold nanoparticles are well‐dispersed on the surface of TiO2‐NTs support. The electrooxidation of hydroquinone of Au‐NPs/TiO2‐NTs electrodes is investigated by different electrochemical methods. Au‐NPs/TiO2‐NTs electrode can be used repeatedly and exhibits stable electrocatalytic activity for the hydroquinone oxidation. Also, determination of hydroquinone in skin cream using this electrode was evaluated. Results were found to be satisfactory and no matrix effects are observed during the determination of hydroquinone content of the “skin cream” samples. 相似文献
66.
Mingfeng Wang Ghasem Rezanejade BardajeeMark Nitz Gregory D. Scholes Mitchell A. Winnik 《Journal of chromatography. A》2009,1216(25):5011-5019
We explore the use of preparative size-exclusion chromatography (SEC) and high-performance liquid chromatography (HPLC) to purify quantum dots (QDs) after surface modification. In one example, in which Bio-Beads (S-X1) were used as the packing material for the preparative SEC column, CdSe QDs treated with a functional coumarin dye could be separated from the excess free dye by using tetrahydrofuran (THF) as the mobile phase. This column was unable to separate polymer-coated QDs from free polymer (M ∼ 8000) because of the relatively low cutoff mass of the column. Here a preparative HPLC column packed with TOYOPEARL gel allowed the effective separation of polymer-bound QDs from the excess free polymer by using N-methyl-2-pyrrolidinone (NMP) as the mobile phase. When other solvents such as absolute ethanol, acetonitrile, THF, and THF–triethylamine mixtures were used as the eluent, QDs stuck to the column. While NMP was an effective medium to remove excess free polymer from the QDs, it was difficult to transfer the purified QDs to more volatile solvents and maintain colloidal stability. 相似文献
67.
Malek Taher Maghsoodlou Nourallah Hazeri Sayyed Mostafa Habibi‐Khorassani Ghasem Marandi Lotfali Saghatforoush Danial Saravani Niloufar Akbarzadeh Torbati Faramarz Rostami‐Charati Khatereh Khandan‐Barani Brian W. Skelton Mohamed Makha 《Heteroatom Chemistry》2010,21(4):222-227
New phosphonate ester derivatives were obtained by in situ stereo‐specific reaction between triphenyl phosphite and dialkyl acetylenedicarboxylates in the presence of a series of halogenated anilines. Spectroscopic data and X‐ray crystallography analysis are in agreement with the gauche arrangement for the two vicinal protons in the structures. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:222–227, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20600 相似文献
68.
Malek Taher Maghsoodlou Sayyed Mostafa Habibi Khorassani Faramarz Rostami Charati Mojtaba Lashkari Ghasem Marandi Mohamed Makha 《Tetrahedron letters》2009,50(31):4439-4442
A one-pot triphenylarsine-catalyzed synthesis of trans-cyclopropane derivatives is achieved by means of the reaction between acetylenic esters and C-H acids in the presence of triphenylarsine. This procedure is simple and proceeds under mild reaction conditions. Its success depends on the choice of solvent, temperature and C-H acid used. 相似文献
69.
Employing variational methods and critical point theory, in an appropriate Orlicz-Sobolev setting, we establish the existence of infinitely many solutions for Steklov problems associated to non-homogeneous differential operators. We also provide some particular cases and a concrete example in order to illustrate the main results. 相似文献
70.
Malek T. Maghsoodlou Nourollah Hazeri Sayyed M. Habibi‐Khorasani Reza Heydari Ghasem Marandi Mahmoud Nassiri 《合成通讯》2013,43(19):2569-2574
The reactive 1∶1 intermediate generated by the addition of alkyl and aryl isocyanides to dialkyl acetylenedicarboxylate was trapped by 2,7‐dinitrofloren‐9‐one and floren‐9‐one to yield iminolactones in good yields. 相似文献