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991.
This paper describes synthesis, characterization and application of a series of Cu(II) complexes with a novel 3‐thioxo‐[1,2,4,5]tetrazocane‐6,8‐dione (N4) macrocyclic ligand. The complexes were characterized by physicochemical and spectroscopic techniques, such as UV–visible and IR spectroscopies, molar conductance, magnetic susceptibility measurements, and elemental analysis. The data suggest that the mononuclear Cu(II) complexes have a metal‐to‐ligand mole ratio of 1:1 and that the Cu(II) ions are coordinated with the four nitrogen atoms inside the N4 macrocyclic ring. The experimental anisotropic g‐values indicate that the chloro, nitrato, acetate, and perchlorato complexes have six‐coordinate distorted octahedral behavior, whereas the sulfato complex has five‐coordinate square‐pyramidal geometry. A simple and nontoxic method for preparation of CuO nanoparticles based upon the thermal decomposition of the synthesized Cu(II) complexes has been explored. Finally, the degradation of Rhodamine 6G dye by the catalytic performance of nano‐sized CuO material has been evaluated. 相似文献
992.
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
993.
Mojgan Ghabarpoor Majid Tavassoli Kajani Masoud Allame 《Mathematical Methods in the Applied Sciences》2019,42(5):1609-1621
This paper presents a new multistep collocation method for nth order differential equations. The interval of interest is first divided into N subintervals. By determining interval conditions in Taylor interpolation in each subinterval, Taylor polynomials are calculated with different step lengths. Then the obtained solutions in each subinterval are used as initial conditions in the next step. Optimal error is assessed using Peano lemma, which shows that the errors decay by decreasing the step length. In particular, for fixed step length h, the error is of O(m?m), where m is the number of collocation points in each subinterval. Meanwhile, for fixed m, the error is of O(hm). Numerical examples demonstrate the validity and high accuracy of the proposed method even for stiff problems. 相似文献
994.
Introduction: The flow of pedestrians through narrow doorways is one of the most common features of crowd motions and evacuations. It is particularly an important aspect of pedestrian simulations models since their accuracy depends highly on their ability to produce realistic exit flow rates. The problem has been extensively studied in the literature, but many aspects of it have remained controversial with mixed (and often contradictory) evidence emerging from different studies and different methods. Methods: We discuss the significance of parameter calibration for accurate simulation of pedestrian flow through narrow exits using social force model. Based on sensitivity analyses, we show how simulated exit throughput rate can vastly differ by changing the value of certain parameters. We identify the two parameters that are most critical, and then calibrate them based on a set of experimental observations (at macro level). Using these calibrated parameters, we then re-examine three fundamental questions related to pedestrian flow at bottlenecks, (1) the relation between desired velocity and simulated egress time; (2) the effect of barricade at exits; and (3) the effect of exit in the corner versus the middle. Results: Our numerical analyses showed that, with the calibrated parameters, increasing the desired velocity in the social-force model results in monotonically shorter egress times (at a marginal rate that rapidly diminishes as the desired velocity increases). We showed that placing a panel-like barricade at exit can facilitate the outflow and reduces the egress time, but its effect depends on the widths of exit, as well as the size of the barricade and its distance to exit. We show that the positioning the exit in the corner is also effective in terms of reducing egress time, but only for very narrow exits. The benefit diminishes quickly as the exit becomes wider. Applications: These outcomes demonstrated the significance of parameter calibration for accurate simulation of crowd flows. The findings may also help to identify simple modifications that can facilitate crowd flows at narrow bottlenecks. 相似文献
995.
Mohammadi Majid Sedighi Mehdi Ghasemi Mostafa 《Research on Chemical Intermediates》2021,47(4):1377-1395
Research on Chemical Intermediates - The primary purpose of this study is to create a method for removal of nitrate and phosphate utilizing adsorption-based technique. To this end, the adsorption... 相似文献
996.
Selective tetrahydropyranylation of alcohols and phenols using titanium(IV) salophen trifluoromethanesulfonate as an efficient catalyst
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Titanium(IV) salophen trifluoromethanesulfonate, [TiIV(salophen)(OSO2CF3)2], as a catalyst enables selective tetrahydropyranylation of alcohols and phenols with 3,4‐dihydro‐2H‐pyran. Using this catalytic system, primary, secondary and tertiary alcohols, as well as phenols, were converted to their corresponding tetrahydropyranyl ethers in high yields and short reaction times at room temperature. Investigation of the chemoselectivity of this method showed discrimination between the activity of primary alcohols in the presence of secondary and tertiary alcohols and phenols. This heterogenized catalyst could be reused several times without loss of its catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
997.
A. K. Arof N. E. A. Shuhaimi N. A. Alias M. Z. Kufian S. R. Majid 《Journal of Solid State Electrochemistry》2010,14(12):2145-2152
In this work, a chitosan/iota (ι)-carrageenan blended film doped with orthophosphoric acid (H3PO4) as ionic dopant and poly(ethylene glycol) (PEG) as plasticizer has been used as a separator and electrolyte in an electrical
double layer capacitor (EDLC). A set of samples were prepared by the solution cast technique to see the effect of the different
weight ratios of the proton donor and plasticizer on the conductivity. The highest conducting sample has composition 37.50 wt.%
chitosan–37.50 wt.% ι-carrageenan–18.75 wt.% H3PO4–6.25 wt.% PEG. The conductivity value is 6.29 × 10−4 S cm−1. The conductivity–temperature relationship is Arrhenian, and the activation energy for the highest conducting sample is 0.09 eV.
The specific discharge capacitance of the EDLC is 35 F g−1 at 0.11 mA cm−2 current drain and was constant for 30 cycles. 相似文献
998.
Al-Hashimi M Labram JG Watkins S Motevalli M Anthopoulos TD Heeney M 《Organic letters》2010,12(23):5478-5481
The synthesis of a novel electron-deficient fused pyrrolo[3,2-d:4,5-d']bisthiazole is reported from 2-bromothiazole. This was copolymerized with thiophene, selenophene, thienothiophene, and bithiophene by microwave-assisted Stille polycondensation. The resulting polymers exhibited small optical band gaps combined with low-lying HOMO energy levels and demonstrated semiconducting behavior in organic field effect transistors. 相似文献
999.
Majid Moghadam Shahram Tangestaninejad Valiollah Mirkhani Naghmeh Sadat Mirbagheri 《Journal of organometallic chemistry》2010,695(17):2014-1368
In the present work, highly efficient epoxidation of alkenes catalyzed by Mo(CO)6 supported on amines modified multi-wall carbon nanotubes, MWCNTs, is reported. The prepared catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV-Vis spectroscopic methods. These new heterogenized catalysts, [Mo(CO)6@amines-MWCNT], were used as highly efficient catalysts for epoxidation of alkenes with tert-BuOOH. These robust catalysts could be reused several times without loss of their catalytic activities. 相似文献
1000.