排序方式: 共有179条查询结果,搜索用时 15 毫秒
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Shahnaz Rostamizadeh Nasrin Shadjou Ali M. Amani Reza Aryan 《Journal of heterocyclic chemistry》2008,45(6):1761-1764
5‐Aryl‐6H‐1,3,4‐thiadiazin‐2‐aminium and 5‐aryl‐N‐phenyl‐6H‐1,3,4‐thiadiazin‐2‐aminium salts have efficiently been synthesized from the reaction of thiosemicarbazide and α‐haloketones in acetonitrile at room temperature using i) silica supported sodium hydrogen sulfate and ii) silica sulfuric acid as reusable heterogeneous catalysts. The experimental procedure is simple and the products are obtained in high yields. 相似文献
173.
External magnetic field-dependent behavior of tricritical points of uniaxial–biaxial nematic phase transition in a mixture of prolate and oblate molecules has been studied using the Landau phenomenological theory. Topological classification of phase diagrams in the field-temperature coordinates is performed using a sixth-order term in order parameter tensor. For both prolate and oblate molecules, the tricritical order parameters corresponding to the uniaxial–biaxial increase with the intensity of the external magnetic field. Field-induced paranematic phase has only been reported for prolate molecules, but for oblate molecules, field-induced splitting of the order parameter has been reported. 相似文献
174.
Shahnaz Rostamizadeha Ali Mohammad Amania Gholam Hossein Mahdavinia Nasrin Shadjoua 《中国化学快报》2009,20(7):779-783
Silica supported ammonium dihydrogen phosphate (NH4H2PO4/SiO2) is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions. 相似文献
175.
In this paper we propose a novel square-lattice photonic crystal fiber (SPCF) for dispersion compensation in a wide range of wavelengths. Perfectly matched layer (PML) is considered for the boundary treatment and an efficient compact two dimensional finite-difference frequency-domain (2-D FDFD) method is employed to model square-lattice photonic crystal fibers (SPCF). It has been shown with selecting appropriate parameters for SPCF it is possible to obtain high negative dispersion coefficient, negative dispersion slope over E to L wavelengths, confinement losses less than 10?5?dB/m and splice losses less than 3.6 dB. The designed SPCF exhibits a relative dispersion slope (RDS) of 3.543 × 10?3 nm?1 which is closely matched to the RDS of conventional single mode fibers. 相似文献
176.
Ute Bergmann Sabine Apelt Nasrin B. Khojasteh René Heller 《Surface and interface analysis : SIA》2020,52(12):1111-1116
A novel Rutherford backscattering spectrometry (RBS) method is presented to investigate the interface between a solid surface and a surrounding liquid. The introduced measurement system allows to observe and quantify adsorption at the solid–liquid interface and the formation of the electrochemical double layer (EDL). BaCl2 as a bicomponent electrolyte and a Si3N4 membrane surface are chosen as a model system to prove the capabilities of the setup. The results of these RBS measurements are combined with electrochemical impedance spectroscopy (EIS) to validate the findings for the solid–liquid interface under study. Complementary results and discrepancies regarding the formation of the EDL are discussed. 相似文献
177.
Moazami Hamid Reza Hosseiny Davarani Saied Saeed Ghassemi Nasrin Hamed Sara 《Journal of Solid State Electrochemistry》2020,24(5):1231-1238
Journal of Solid State Electrochemistry - The present work describes a facile route for the synthesis of CdMn2O4 nanoplates. The nanoplates were synthesized by cathodic electrogeneration of base... 相似文献
178.
A new magnetic nanocatalyst (Fe3O4@KCC-1-npr-NH2) was synthesized directly through the reaction of Fe3O4@KCC-1 with (3-aminopropyl) triethoxysilane (APTES) using a hydrothermal protocol. Prepared nanocomposite was used as a magnetically reusable nanocatalyst for an efficient synthesis of a broad range of sulfonamide derivatives in water as a green solvent at room temperature and the products are collected by filtration with excellent yields (85–97%). The nanocatalyst could be remarkably recovered and reused after ten times without any significant decrease in activity. This mild and simple synthesis method offers some advantages including short reaction time, high yield and simple work-up procedure. 相似文献
179.
Nasrin Alishahi Mahboobeh Nasr-Esfahani Iraj Mohammadpoor-Baltork Shahram Tangestaninejad Valiollah Mirkhani Majid Moghadam 《应用有机金属化学》2020,34(8):e5681
In this study, an acidic nicotine-based ionic liquid supported on magnetic nanoparticles ([NicTC]HSO4@MNPs) was synthesized and characterized by different techniques. The activity of this catalyst was evaluated in a multi-component reaction of 2-aminobenzothiazole , aldehydes / dialdehydes and β-ketoesters/1,3-diketones to afford a series of novel mono- and bis-4H-pyrimido[2,1-b]benzothiazole derivatives. In addition, mild reaction conditions, high yields, excellent selectivity as well as easy recovery and reusability of the catalyst, make this method an economic and environmentally-benign process. 相似文献