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91.
A. Mobinikhaledi N. Foroughifar J. Alipour Safari T. Mosleh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2329-2335
3-Oxo-2-[(Z)-1-phenylmethylidene]-5H-[1,3]thiazolo[3,2-a] pyrimidine derivatives 2a–f were synthesized by the reaction of an appropriate 3,4-dihydro-2(H)-pyrimidone 1 , chloroacetic acid, sodium acetate and benzaldehyde. Reaction of 1 with acetic anhydride under heating afforded only 3-N-acetylated 3,4-dihydro-2(H)-pyrimidines 3a–f . The yields of the products after recrystallization from ethanol were of the order of 60–92 %. IR, 1 H NMR spectroscopy, and elemental analysis were used for the identification of these compounds. 相似文献
92.
Vocal Fold Elasticity in the Pig, Sheep, and Cow Larynges 总被引:1,自引:0,他引:1
93.
Zahra Mohammadzahery Maryam Jandaghi Samira Alipour Siamak Dadras Shahram Kazemi Jamshid Sabbaghzadeh 《Optics & Laser Technology》2012,44(4):1095-1100
This study deals with the thermal characterization of a continuous wave (CW-) and end-pumped passively Q-switched microchip Nd:YAG laser crystal by solving the rate and heat transfer equations in the laser cavity. In this approach, a parametric study has been performed to investigate the influence of the pumping parameters, cooling metal dimension and also the crystal dimension and doping concentration on the thermal behavior of the laser crystal. Obtained results reveal a closed correlation between the mentioned parameters and the thermal behavior of the crystal indicating that a proper selection of the laser parameters is essential to control the crystal's temperature and improve the performance of the laser accordingly. 相似文献
94.
Stephan Wulfinghoff Atefeh Alipour Shahed Rezaei Julian Kochmann Stefanie Reese 《PAMM》2016,16(1):411-412
Gradient plasticity can account for experimentally observed size effects. Here, a previously developed gradient plasticity model is extended to account for interface delamination processes. The crystal plasticity model is based on the gradient of an equivalent plastic strain measure. A modification of the related boundary conditions allows for the formulation of a generalized cohezive zone model which can take into account the effect of interface delamination on the gradient plasticity solution. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
95.
Mehdi Bakavoli Mohammad Rahimizadeh Esmaeel Rezaei-Seresht Majid Mokaber Esfahani Parisa Ziaee 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2152-2158
The synthesis of some novel crown and thiacrown ethers via the reaction of 2,3-bis(4-hydroxyphenyl) or 2,3-bis(4-mercaptophenyl)quinoxalines and pyridopyridazine with diethylene and triethylene glycol ditosylate is described. The complexing ability of compounds 5b and 5h, as the representatives of both groups of compounds, with alkali and alkali earth metal cations were measured by the solvent extraction method. The results showed that crown ether 5b comparatively had more affinity towards the Mg2+ cation, while thiacrown ether 5h had greater affinity towards the Ca2+ cation. 相似文献
96.
Fatahian Hossein Jouybari Nima Fallah Nimvari Majid Eshagh Fatahian Esmaeel Zhang Wennan 《Journal of Thermal Analysis and Calorimetry》2022,147(22):12919-12931
Journal of Thermal Analysis and Calorimetry - The present study deals with the numerical simulation of turbulent flow in a Z-type manifold in which the fluid is distributed via nine distribution... 相似文献
97.
Mohammad Zaman Kassaee Farnaz Alipour Shakib Mohammad Reza Momeni Mehdi Ghambarian Seyed Majid Musavi 《Monatshefte für Chemie / Chemical Monthly》2009,9(4):33-38
Abstract
Based on geometries and relative energies, three different mechanisms are proposed for the rearrangements of five isomers of silacyclohexadienylidenes to silabenzene at B3LYP and MP2 levels: (1) [1,2]-hydrogen migration through a planar transition state, (2) [1,4]-hydrogen migration through a boat transition state, and (3) zip-zap mechanism, comprised of three successive [1,2]-hydrogen migrations. The above results are compared and contrasted to rearrangements of the corresponding cyclohexadienylidenes to benzene. 相似文献98.
LiBF4 integrated into [BMIm]BF4: an ionic‐liquid metal composite and homogeneous catalyst for efficient synthesis of pyran‐annulated heterocycles 下载免费PDF全文
The ionic liquid [BMIm]BF4 doped with LiBF4 was found to efficiently catalyze the three‐component reaction between isocyanides, acetylenic esters and enols or phenols at room temperature, leading to rapid synthesis of 2‐aminopyran‐annulated systems in fairly high yields. Efficiency of this catalysis and its benefits in terms of improved yields and reaction times could be ascribed to involvement of relatively stable organolithium intermediates which make the reaction more feasible. The ionic solution tolerates a significant amount of dissolved LiBF4, while remaining fluid at room temperature to serve as solvent for the organic substrates. It retains its initial integrity after use and recovery, as it could be recycled several times without appreciable catalytic decrements. The catalytic activity of the ionic composite is completely lost in the absence of LiBF4. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
99.
Shannon information entropy of fractional occupation probability as an electron correlation measure in atoms and molecules 总被引:1,自引:0,他引:1
A new method to determine electron correlation energy is presented for atoms and molecules. This method is based on Shannon information entropy that is obtained by fractional occupation probabilities of natural atomic orbitals. It is indicated that the Shannon entropy increases as the number of electrons increases and thus can be considered as a possible measure for the electron correlation in atomic and molecular systems. For neutral atoms and singly charged positive ions we proposed an expression for correlation energy with explicit dependence on the Shannon entropy and atomic number. The obtained correlation energies have been used to compute the first ionization potentials of the ground state of the main group elements from hydrogen through krypton. The calculated ionization potentials are in reasonably good agreement with their corresponding experimental values.We also developed the additivity scheme to find a connection between Shannon entropy and molecular correlation energy. The estimated molecular correlation energies show an excellent agreement with those obtained by elaborate G3 method with R2 = 0.990. 相似文献
100.
Rubber compounds based on styrene-butadiene rubber/ethylene propylene diene monomer blends of different compositions (60/40, 70/30, 80/20, 90/10, 100/0) reinforced with 1 wt%, 3 wt%, 5 wt% and 7 wt% organoclay (Cloisite 20A) were prepared on a two roll mill via a vulcanization process and characterized by several techniques. Results of X-ray diffraction showed expansion of the inter-gallery distance, and transmission electron microscopy (TEM) micrographs confirmed that the prepared nanocomposite samples have intercalated and partially exfoliated structures. Cure characteristics showed that, organoclay not only accelerates the vulcanization reaction, but also gives rise to a marked increase of the torque, indicating crosslink density of the prepared compounds increases at the presence of organoclay. Mechanical properties of samples received markedly increase by clay loading due to the good interaction established between nanoclay particles and polymer matrix as it was evidenced by SEM photomicrographs. At the same time, rheological properties showed that addition of nanoclay could improve storage modulus as well as complex viscosity of SBR/EPDM samples. The results of ozone test revealed that the ozone resistance of samples significantly increases as nanoclay or EPDM content increases. 相似文献