排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
Rahman Hosseinzadeh Mahmood Tajbakhsh Maryam Mohadjerani Parizad Rezaei Mohammad Alikarami 《合成通讯》2013,43(17):3023-3031
An efficient synthesis of diaryl ethers by the copper-catalyzed arylation of phenols with a variety of aryl iodide susing KF/Al2O3 as a suitable base and CuI and 1,3 diphenyl-1,3 propandione as the catalyst is described. 相似文献
2.
S.E. KHADEMM. REZAEE 《Journal of sound and vibration》2002,254(4):677-691
In this paper, the non-linear free vibration of a string with large amplitude is considered. The initial tension, lateral vibration amplitude, cross-section diameter and the modulus of elasticity of the string have main effects on its natural frequencies. Increasing the lateral vibration amplitude makes the assumption of constant initial tension invalid. Therefore, it is impossible to use the classical equation of transverse motion assuming a small amplitude. On the other hand, by increasing the string cross-sectional diameter, the bending moment effect will increase dramatically, and it will act as an impressive restoring moment. Considering the effects of the bending moments, the non-linear equation governing the large amplitude transverse vibration of a string is derived. The time-dependent portion of the governing equation has the form of the Duffing equation. Due to the complexity and non-linearity of the derived equation and the fact that there is no established exact solution method, the equation is solved using the perturbation method. The results of the analysis are shown in appropriate graphs, and the natural frequencies of the string due to the non-linear factors are compared with the natural frequencies of the linear vibration of a string without bending moment effects. 相似文献
3.
FARSHID TABBAKH MOJTABA MOSTAJAB ALDAAVATI MAHDIEH SADAT HOSEYNI KHADIJEH REZAEE EBRAHIM SARAEE 《Pramana》2012,78(2):257-264
In this paper the photonuclear interaction induced by 10 MeV electron beam generating high-intensity neutrons is studied.
Since the results depend on the target material, the calculations are performed for Pb, Ta and W targets which have high Z, in a simple geometry. MCNPX code has been used to simulate the whole process. Also, the results of photon generation has
been compared with the experimental results to evaluate the reliability of the calculation. The results show that the obtained
neutron flux can reach up to 1012 n/cm2/s with average energies of 0.9 MeV, 0.4 MeV and 0.9 MeV for these three elements respectively with the maximum heat deposited
as 3000 W/c3, 4500 W/c3 and 6000 W/c3. 相似文献
4.
二氧化钛纳米粒子催化合成Hantzsch酯和多氢喹啉衍生物(英文) 总被引:2,自引:0,他引:2
Mahmood TAJBAKHSH Ehsan ALAEE Heshmatollah ALINEZHAD Mohammad KHANIAN Fatemeh JAHANI Samad KHAKSAR Parizad REZAEE Mahgol TAJBAKHSH 《催化学报》2012,(9):1517-1522
1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse. 相似文献
5.
Ghahremani Mahboubeh Davarpanah Jamal Rezaee Parizad Davoodi Ghazal 《Research on Chemical Intermediates》2020,46(5):2683-2704
Research on Chemical Intermediates - In this study, the nanoparticles of amorphous silica were easily extracted from low-cost rice husk ash. They were functionalized with 3-(chloropropyl)... 相似文献
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A heteropolyacid efficiently catalyzed the cyclocondensation reaction of 2-aminobenzamide and salicylamide with aldehydes and ketones to afford good yields of benzoxazine and quinazoline ring systems in an aqueous medium. The method gives clean reactions, has simple workup procedure, and uses environment friendly conditions. 相似文献
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Nanosilica-bonded N-(propylsulfonyl) piperazine-N-sulfamic acid was easily prepared by functionalizing silica nanoparticles and characterized by thermogravimetric analysis, scanning electron microscopy, infrared (IR) spectroscopy, elemental analyses, and ion-exchange pH analysis. The catalytic activity of the functionalized nanosilica for preparation of 1,1′-(arylmethylene) diureas from reaction of aldehydes with urea derivatives was examined. The efficient effect of this catalyst led to preparation of 1,1′-(arylmethylene) diureas in high yield. The reaction of aldehydes with thiourea under the same reaction conditions afforded high yield of 1,3,5-triazinane-2,4-dithiones. Catalyst reusability, simple workup procedure, and short reaction time are other advantages of this protocol. 相似文献
9.
Davarpanah Jamal Rezaee Parizad Ghahremani Mahboubeh Hajiabdolah Nafiseh 《Research on Chemical Intermediates》2022,48(10):4033-4047
Research on Chemical Intermediates - In this research, SBA-amino-amido-carboxylic acid (SBA-NH-NHCO-COOH) is synthesized by nucleophilic substitution of SBA propylchloride (SBA-Cl) with ethylene... 相似文献
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