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排序方式: 共有355条查询结果,搜索用时 31 毫秒
61.
Khalili B Jajarmi P Eftekhari-Sis B Hashemi MM 《The Journal of organic chemistry》2008,73(6):2090-2095
New 2-alkyl-5-aryl-(1H)-pyrrole-4-ol derivatives were synthesized via three-component reaction of beta-dicarbonyl compounds with arylglyoxals in the presence of ammonium acetate in water at room temperature. 相似文献
62.
Primary and secondary benzylic alcohols were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant, H2O2 catalyzed by montmorillonite K-10 supported cobalt(Ⅱ) chloride. 相似文献
63.
Let R be a semiprime left Goldie ring with
a monomorphism and
an α-derivation, then
is semiprimitive left Goldie ring. 相似文献
64.
Seyfollah Toroghi Ahmad Khayat Jafari Ala Hashemi Golpayegani 《Optics & Laser Technology》2009,41(6):800-803
In this paper, the dependence of the absorbed power on the temperature in an end-pumped CW quasi-three-level Yb:YAG thin disk laser is calculated. Here, we have used the temperature-dependent form of the Boltzmann occupation factors, absorption cross-section and thermal conductivity of the Yb:YAG crystal. A Monte Carlo ray tracing code and a 2D finite element analysis (FEA) with the ANSYS package have been used to calculate the absorbed power and the temperature distribution inside the Yb:YAG thin disk laser, respectively. According to the model, the temperature-dependent absorbed power turns out to be 18% less than the temperature-independent absorbed power in the top center of the Yb:YAG thin disk laser for used parameters. 相似文献
65.
Najmedin Azizi Alireza Khajeh Amiri Roya Baghi Mohammad Bolourtchian Mohammad M. Hashemi 《Monatshefte für Chemie / Chemical Monthly》2009,3(2):1471-1473
Abstract
p-Toluenesulfonic acid (10 mol%) was found to be an effective and efficient catalyst for the synthesis of 2-substituted benzothiazoles from aromatic aldehydes and 2-aminothiophenol in moderate to excellent yields in water. This method provides a simple and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst, and simple workup procedure. 相似文献66.
M. Hashemi 《Ukrainian Mathematical Journal》2009,61(12):1995-2007
We study two classes of 2-generated nilpotent groups of nilpotency class 2 and compute the order of their automorphism groups. 相似文献
67.
In this work, we consider a vacuum solution of Kaluza–Klein theory with cylindrical symmetry. We investigate the physical properties of the solution as viewed in four dimensional spacetime, which turns out to be a stationary, cylindrical wormhole supported by a scalar field and a magnetic field oriented along the wormhole. We then apply a boost to the five dimensional solution along the extra dimension, and perform the Kaluza–Klein reduction. As a result, we show that the new solution is still a wormhole with a radial electric field and a magnetic field stretched along the wormhole throat. 相似文献
68.
Sousan Rasouli Amir-Masoud Arabi Alireza Naeimi Seyed-Masoud Hashemi 《Journal of fluorescence》2018,28(1):167-172
Nanoparticles of Europium oxide doped with Zinc oxide were synthesized via microwave-assisted combustion method. Citric acid as a simultaneous fuel and chelating agent and glycine as a fuel and mixture of these fuels were sleeted. X-Ray diffraction patterns (XRD) indicated the formation of ZnO structure with a few amount of Eu2O3 phase. Fourier transformation infra red (FTIR) spectra reveal the increase of ZnO4 bonds with glycine content of fuels mixture. Scanning electron microscope (SEM) images showed the conversion of nanosphere to spongy-like structure with respect to change of fuel mixtures from citric to glycine. From transmission electron microscopy (TEM) nanoparticles of a mean size 30 nm are observed Green fluorescence emission of different samples was due to activation of self activated center of ZnO structure through transition of electron from Eu3+ to Vzn sites. 相似文献
69.
Julio Garcia Michael Markl Susanne Schnell Bradley Allen Pegah Entezari Riti Mahadevia S. Chris Malaisrie Philippe Pibarot James Carr Alex J. Barker 《Magnetic resonance imaging》2014
Aims
The objective of this study was to evaluate the potential of 4D flow MRI to assess valve effective orifice area (EOA) in patients with aortic stenosis as determined by the jet shear layer detection (JSLD) method.Methods and Results
An in-vitro stenosis phantom was used for validation and in-vivo imaging was performed in 10 healthy controls and 40 patients with aortic stenosis. EOA was calculated by the JSLD method using standard 2D phase contrast MRI (PC-MRI) and 4D flow MRI measurements (EOAJSLD-2D and EOAJSLD-4D, respectively). As a reference standard, the continuity equation was used to calculate EOA (EOACE) with the 2D PC-MRI velocity field and compared to the EOAJSLD measurements. The in-vitro results exhibited excellent agreement between flow theory (EOA = 0.78 cm2) and experimental measurement (EOAJSLD-4D = 0.78 ± 0.01 cm2) for peak velocities ranging from 0.9 to 3.7 m/s. In-vivo results showed good correlation and agreement between EOAJSLD-2D and EOACE (r = 0.91, p < 0.001; bias: − 0.01 ± 0.38 cm2; agreement limits: 0.75 to − 0.77 cm2), and between EOAJSLD-4D and EOACE (r = 0.95, p < 0.001; bias: − 0.09 ± 0.26 cm2; limits: 0.43 to − 0.62 cm2).Conclusion
This study demonstrates the feasibility of measuring EOAJSLD using 4D flow MRI. The technique allows for optimization of the EOA measurement position by visualizing the 3D vena contracta, and avoids potential sources of EOACE measurement variability. 相似文献70.
Hashemi Zahra Ebrahimzadeh Mohammad Ali Biparva Pourya 《Journal of fluorescence》2022,32(5):1669-1678
Journal of Fluorescence - A wide variety of medical, biomedical, and industrial applications has been reported for quinoxalines derivatives. In this work, a novel quinoxaline derivative was... 相似文献