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排序方式: 共有108条查询结果,搜索用时 15 毫秒
71.
Abderrahmane Ararem Abdelkader Bouzidi Brahim Mohamedi Omar Bouras 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(3):881-887
A low-cost, non-toxic and effective adsorbent constituted by a montmorillonite coated by iron oxides (montmorillonite–iron oxide composite) was prepared to assess its effectiveness in the removal of Cs+ and Sr2+ from aqueous solution. Dynamic adsorption experiments were carried out at room temperature under the effect of various operating parameters such as bed depth Z (5–15 cm), initial cation concentration C 0 (2–50 mg L?1) and volumetric flow rate Q (0.5–8 mL min?1). Column performance has been modeled with constant-pattern wave approach combined to the Freundlich isotherm model and artificial neural network (ANN) models. The time, initial cation concentration, bed depth and volumetric flow rate were chosen as the input variables whereas, the outlet concentration C t was considered as the output variable. The developed network was found to be useful in predicting the breakthrough curves. Experimental data for the used system were well fitted with ANN than the combined constant–pattern wave approach. 相似文献
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A numerical study of a supersonic planar two-throat nozzle flow, using the Reynolds averaged Navier–Stokes equations, is presented. This nozzle flow can induce asymmetrical separation between the throats. The start-up processes are examined. Initial pressure ratio and increasing pressure time influence are investigated. The objective is to gain a better understanding of the mechanisms causing the asymmetry. 相似文献
75.
Tzu-Pin Lin Pauline Gualco Sonia Ladeira Abderrahmane Amgoune Didier Bourissou François P. Gabbaï 《Comptes Rendus Chimie》2010,13(8-9):1168-1172
Monophosphine and diphosphine-stannane compounds 1 and 2 are shown spectroscopically, structurally and theoretically to present rare intramolecular P→Sn interactions. 相似文献
76.
Syrine Daoudi Abderrahmane Semmeq Michael Badawi Xavier Assfeld Youssef Arfaoui Mariachiara Pastore 《Journal of computational chemistry》2019,40(29):2530-2538
Seven free base porphyrins employed in dye-sensitized photoelectrosynthetic cells are investigated with the aim of benchmarking the ability of different density functional theory (DFT) and time-dependent DFT approaches in reproducing their structure, vertical, and E0-0 excitation energies and the energy levels alignment (red-ox properties) at the interface with the TiO2. We find that both vertical and E0-0 excitation energies are accurately reproduced by range-separated functionals, among which the ω B97X-D delivers the lowest absolute deviations from experiments. When the dye/TiO2 interface is modeled, the physical interfacial energetics is only obtained when the B3LYP functional is employed; on the other hand, M06-2X (54% of exchange) and the two long-range corrected approaches tested (CAM-B3LYP and ω B97X-D) excessively destabilize the semiconductor conduction band levels with respect to the dye's lowest unoccupied molecular orbitals (LUMOs), predicting no pathway for electron injection. © 2019 Wiley Periodicals, Inc. 相似文献
77.
The hydrothermal reaction of 2-cyanopyrimidine and either CoCl2.6H2O or FeCl2.4H2O affords 2D isostructural coordination polymers [M2(micro-pymca)3]OH.H2O ((M = CoII (1) and FeII (2) pymca = pyrimidine-2-carboxylato). The bisdidentate ligand (pymca) that can be considered an intermediate between bipyrimidine and oxalato is generated in situ from the hydrolysis of 2-cyanopyrimidine. The structure of 1 and 2 consists of heterochiral (6,3) honeycomb layers, crystal water molecules, and OH- anions, the latter playing a template and balancing charge role in the structure. Both compounds exhibit antiferromagnetic interactions between metal ions through the pyrimidine-2-carboxylate bridging ligand. Compound 1 is a spin-canted antiferromagnet leading to weak ferromagnetism at Tc < 10 K with a coercitive field of 580 Oe, whereas compound 2 is an antiferromagnet with TN = 21 K. Fit of the variable-temperature magnetic susceptibility data of 2 to the empirical equation for a regular honeycomb with S = 1 derived from Monte Carlo simulations leads to the following parameters: J = -4.57(2) cm-1 and g = 2.300(4). Density functional calculations have been used to explain the magnetic coupling in 2. 相似文献
78.
利用大肠杆菌启动子探测质粒pKK232-8为载体,经HindⅢ-BamHⅠ完全消化后与HindⅢ-BamHⅠ部分消化的嗜麦芽假单胞菌染色休DNA进行体外连接,转化E.coliHB101感受态细胞,在含氨苄青霉素(Ap)和氯霉素(Cm)的选择平板上筛选转化子.从随机挑选的54株转化子中,获得一株抗氯霉素水平达1000mg/L的转化子E.coliPASI,所含重组质粒被命名为pASI.经限制性酶切分析和杂交分析表明,pASI质粒上插入了一段来源于嗜麦芽假单胞菌染色体的DNA片段,其大小为1.4kb.SDS-PAGE分析表明转化子E.coliPASI在含Cm的培养基上,额外表达了一条22×103的CAT蛋白质带.将重组质粒pWSY上的嗜麦芽假单胞菌mel基因亚克隆到pASI上1.4kb启动子功能片段下游,构建成E.coliAWS工程菌株,使黑色素产率提高了70.6%. 相似文献
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Journal of Thermal Analysis and Calorimetry - The present work deals with thermal regulation of a spherical electronic device used in naval navigation techniques. Cooling is achieved by means of... 相似文献