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11.
Salahudeen Nurudeen Ahmed Abdulkarim S. Al-Muhtaseb Ala’a H. Dauda Mohammed Jibril Baba Y. Viswanadham Nagabhatla Saxena Sandeep K. 《Research on Chemical Intermediates》2017,43(1):467-479
Research on Chemical Intermediates - This study presents the synthesis of rare earth-doped Y (RE Y) zeolite, its application in formulation of a fluid catalytic cracking (FCC) catalyst and the... 相似文献
12.
Ala Hasan 《Heat and Mass Transfer》2005,41(8):724-733
The thermal-hydraulic performance of five oval tubes is experimentally investigated and compared with that for a circular tube in a cross-flow of air. The range of Reynolds numbers ReD is approximately between 1,000 and 11,000. The nominal axis ratios R (major axis/minor axis) for three of the investigated oval tubes are 2, 3, and 4. Two other configurations of oval tubes are also tested, an oval tube R=3 with two wires soldered on its upper and lower top positions, and a cut-oval tube. The performance of the tubes is corrected for the effects of area blockage and turbulence intensity. The measurement results show that the mean Nusselt numbers NuD for the oval tubes are close to that for the circular tube for ReD<4,000. For a higher ReD, the NuD for the oval tubes is lower than that for the circular tube and it decreases with the increase in the axis ratio R. The drag coefficients Cd for the tubes are measured and the combined thermal-hydraulic performance is indicated by the ratio NuD/Cd, which shows a better combined performance for the oval tubes. 相似文献
13.
A meshless particle method based on an unconditionally stable time domain numerical scheme, oriented to electromagnetic transient simulations, is presented. The proposed scheme improves the smoothed particle electromagnetics method, already developed by the authors. The time stepping is approached by using the alternating directions implicit finite difference scheme, in a leapfrog way. The proposed formulation is used in order to efficiently overcome the stability relation constraint of explicit schemes. In fact, due to this constraint, large time steps cannot be used with small space steps and vice-versa. The same stability relation holds when the meshless formulation is applied together with an explicit finite difference scheme accounted for the time stepping. The computational tool is assessed and first simulation results are compared and discussed in order to validate the proposed approach. 相似文献
14.
The Zn(II) complex, dichloro[N-hydroxy-1,1-di(2-pyridinyl)methanimine]zinc(II), was synthesized from the reaction between ZnCl2 and di-2-pyridylketone oxime. The structural and spectral characterizations were performed by using single crystal X-ray diffraction, FT-IR, Laser-Raman, NMR and UV–Vis spectroscopic techniques. To support experimental evidences, computational results were obtained with the DFT/B3LYP method using the 6-311++G(d,p)+LanL2DZ mixed basis set. Theoretical analyses of some structural and spectroscopic results of effects of intermolecular Cl···H interactions in the crystal packing of the Zn(II) complex were investigated with the mentioned computational level. The non-bonding interactions in the experimental crystal packing of the complex were examined by Hirshfeld surface analysis. The HOMO and LUMO analyses were used for investigation of electronic transitions obtained with UV–Vis spectroscopy. NBO analyses were used to investigate the hyperconjugation interactions between donor and acceptor groups, coordination environment, electronic configuration and electron numbers of the Zn(II) metal ion and the natural atomic charges of the complex. The nucleophilic and electrophilic reactive sites of the complex were studied by MEP surface analysis. The static polarizabilities (α) and static hyperpolarizabilities (β) were analyzed theoretically to characterize NLO profile of the complex. The interaction with A-DNA (PDB ID: 1ZF6) of the Zn(II) complex was investigated with a molecular docking study. 相似文献
15.
16.
Ala Alnaser 《Journal of Number Theory》2008,128(9):2582-2590
Let p be an odd prime and γ(k,pn) be the smallest positive integer s such that every integer is a sum of s kth powers . We establish γ(k,pn)?[k/2]+2 and provided that k is not divisible by (p−1)/2. Next, let t=(p−1)/(p−1,k), and q be any positive integer. We show that if ?(t)?q then γ(k,pn)?c(q)k1/q for some constant c(q). These results generalize results known for the case of prime moduli.
Video abstract
For a video summary of this paper, please visit http://www.youtube.com/watch?v=zpHYhwL1kD0. 相似文献17.
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
18.
Mohammad Rahimizadeh Mehdi Pordel Mehdi Bakavoli Zahra Bakhtiarpoor Ala Orafaie 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):633-638
Abstract New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl3. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug.
Graphical abstract
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19.
Mohammad Rahimizadeh Mehdi Pordel Mehdi Bakavoli Zahra Bakhtiarpoor Ala Orafaie 《Monatshefte für Chemie / Chemical Monthly》2009,20(2):633-638
Abstract
New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl3. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug. 相似文献20.
A selective and sensitive room-temperature phosphorimetric method for the direct determination of 1-naphthoxylactic acid (NA) in biological fluids is described. It is based on obtaining a phosphorescence signal from NA using TlNO3 as a heavy atom perturber and Na2SO3 as a deoxygenator without a protective medium. This technique is named non-protected room-temperature phosphorescence (NP-RTP), which allows to determine analytes in complex matrices without the need for tedious prior separation. Optimization of the operational conditions resulted in a detection limit for NA of 9.6 ng/mL according to the error propagation theory. The repeatability and standard deviation were also determined. This method was successfully applied to the determination of NA in urine and human serum. 相似文献