排序方式: 共有139条查询结果,搜索用时 312 毫秒
91.
Seyed Ali HOSSEINI Mohammad Taghi SADEGHI-SORKHANI Leila KAFI-AHMADI Abdolali ALEMI Aligholi NIAEI Dariush SALARI 《催化学报》2011,32(9):1465-1468
Nanostructured LaFeO3 and substituted La1-xEuxFeO3 (x = 0.1, 0.15, and 0.2) perovskites were synthesized by sol-gel auto-combustion and their activities during the combustion of toluene were evaluated. The structure and physico-chemical properties of the perovskites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and BET surface area analyses. The compounds were crystallized as a perovskite phase with an orthorhombic structure. The mean particl... 相似文献
92.
M. M. Rahmati A. Abdipour A. Mohammadi G. Moradi 《Analog Integrated Circuits and Signal Processing》2011,66(3):349-361
In this paper, a novel method is introduced to predict the Code-Division Multiple-Access (CDMA) output spectrum of an RF power
amplifier linearized with feedforward technique based on transfer function. In this method, an RF power amplifier is modeled
mathematically by nonlinear complex envelope transfer function based on AM-AM and AM-PM distortion diagrams. Using this model,
analytic expressions of CDMA output spectrum of power amplifier is calculated. Having mathematical model of RF power amplifier
leads to derive analytic expressions for InterModulation (IM) products in feedforward amplifier. Based on these expressions,
IM products are related to nonlinear complex envelope transfer function of feedforward amplifier. Then, CDMA output spectrum
of feedforward linearization technique is predicted. The loops imbalances in feedforward technique are considered in analysis.
Finally, the results of derived expressions in MATLAB software are compared with ADS simulations results and good agreements
were achieved. Employing this method gives insight for feedforward analysis and loops imbalances effects in feedforward amplifier
for CDMA applications. 相似文献
93.
An efficient synthesis of 3-(3-methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one derivatives by the reaction of salicylaldehydes, 4-hydroxy-6-methyl-2H-pyran-2-one, and arylhydrazine in acetonitrile under reflux condition and in the presence of piperidine is reported. This three-component reaction has some advantages such as ease of handling, good yields, and easy purification. All structures were confirmed by infrared, mass, 1H NMR, and 13C NMR spectroscopy. 相似文献
94.
Abdolali Alizadeh Hamid Reza Esmaili zand Vahid Saberi Javad Mokhtari 《Helvetica chimica acta》2013,96(12):2240-2244
An efficient approach for the preparation of functionalized 5‐aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles 2 is described. This three‐component reaction between benzaldehydes 1 , NH2NH2?H2O, and 1,1‐bis(methylsulfanyl)‐2‐nitroethene proceeds in EtOH under reflux conditions in good‐to‐excellent yields. The structures of 2 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS). A plausible mechanism for this type of reaction is proposed (Scheme 2). 相似文献
95.
An unexpected approach to the preparation of quinoxaline and pyrido[2,3‐b]pyrazine derivatives 5 is described. The reaction between 1H‐indole‐2,3‐diones 1 , 1‐phenyl‐2‐(triphenylphosphoranylidene)ethanone ( 2 ), and benzene‐1,2‐ or pyridine‐2,3‐diamines 3 proceeds in MeOH under reflux in good to excellent yields (Scheme 1 and Table). No co‐catalyst or activator is required for this multi‐component reaction (MCR), and the reaction is, from an experimental point of view, simple to perform. The structures of 5, 5′ , and 6 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and were confirmed by comparison with reference compounds. A plausible mechanism for this type of reaction is proposed (Scheme 2). 相似文献
96.
Maryam Moosavifar Abdolali Alemi Mohammad Reza Marefat Nasrin Nouruzi Hossein Mahmoodi 《Journal of the Iranian Chemical Society》2014,11(6):1561-1567
In this study, we improved the catalytic performance of manganese porphyrin encapsulated HY zeolite for alkene epoxidation reaction. For this purpose, Manganese tetra pyridyl porphyrin encapsulated into modified dealuminated Y zeolite (MnTPP-MDAZY) was synthesized using zeolite template synthesis method. This heterogenized catalyst was characterized by FT-IR, UV–Vis, XRD and atomic absorption spectra (AAS) technique. Catalyst loading was 0.263 mmol/g support. In this way, high catalyst loading is probably related to the decrease of the size of metalloporphyrin and the post-synthesis treatment. The latter one causes the increase of the diameter of the mesoporous structure as a result of the dealumination of zeolite with EDTA treatment. High catalyst loading efficiently enhances the epoxidation of alkenes. 相似文献
97.
Issa Yavari Zinatossadat Hossaini Abdolali Alizadeh 《Monatshefte für Chemie / Chemical Monthly》2006,137(8):1083-1088
Summary. The reaction between trialkyl(aryl) phosphites and dibenzoylacetylene or dimethyl acetylenedicarboxylate in the presence of
4-nitrophenol leads to stable meso-bisphosphonate derivatives in good yields. 相似文献
98.
Issa Yavari Zinatossadat Hossaini Abdolali Alizadeh 《Monatshefte für Chemie / Chemical Monthly》2006,10(3):1083-1088
The reaction between trialkyl(aryl) phosphites and dibenzoylacetylene or dimethyl acetylenedicarboxylate in the presence of
4-nitrophenol leads to stable meso-bisphosphonate derivatives in good yields. 相似文献
99.
100.
Abdolali Alizadeh Sadegh Rostamnia Nasrin Zohreh Hamid Reza Bijanzadeh 《Monatshefte für Chemie / Chemical Monthly》2008,139(1):49-52
Summary. The three-component reaction of the zwitterions generated from dialkyl acetylenedicarboxylate and isocyanides with isocyanates
is described. The reaction afforded the corresponding special type of ethylenetetracarboxylic acid derivatives in good yields. 相似文献