排序方式: 共有142条查询结果,搜索用时 727 毫秒
41.
42.
Zohra N. Kayani Rabia Ishaque Bareera Zulfiqar Saira Riaz Shahzad Naseem 《Optical and Quantum Electronics》2017,49(6):223
The consequence of annealing on the micro-structural and electrochemical characteristics of Al doped CoZnO thin films deposited by sol–gel dip coating technique are studied. X-ray diffraction indicates that films have a hexagonal wurtzite structure oriented towards the (100). Optical properties of films are recorded by transmission curves utilising a UV–VIS spectrophotometer. The investigation of the optical transmission spectra indicates that the band gap of the films decrease from 3.99 eV to minimum 3.83 eV upon annealing. All films show room temperature ferromagnetism whose magnetization increases with annealing. Dip coated films possess polycrystalline nanosized grains with porous morphology. 相似文献
43.
Asad Ullah Saira Ahmad Milan Maric Syed Mujtaba Shah Hazrat Hussain 《Journal of polymer science. Part A, Polymer chemistry》2022,60(16):2488-2499
A low temperature ATRP of methacryloisobutyl POSS (POSS-MA) is carried out, using poly(propylene glycol) (PPG)-based macroinitiator, in toluene with CuCl/PMDETA as the catalyst system, generating well-defined P(POSS-MA)-b-PPG-b-P(POSS-MA) triblock copolymer with Ð ~ 1.1. The semilogarithmic kinetic plot reveals first-order kinetics and the dispersity is observed to decrease as the reaction progresses—an indication of the controlled behavior of the polymerization. To assess the chain-end fidelity of the produced block copolymer, chain extension is carried out with oligo(ethylene glycol methacrylate) (OEGMA) that afforded water-soluble P(OEGMA)-b-P(POSSMA)-b-PPG-b-P(POSSMA)-b-P(OEGMA) pentablock copolymers. The SEC profiles suggest a quantitative initiation by the macroinitiator. By varying the monomer to initiator molar ratio, block copolymers with various P(OEGMA) chain lengths, ranging from 19 to 58 units on each side have been achieved with relative lower dispersity (Ð < 1.4). Kinetic analysis of the ATRP of OEGMA, with P(POSSMA)-b-PPG-b-P(POSSMA) as the macroinitiator, suggests first-order kinetics and controlled nature of the polymerization. The PPG and P(OEGMA) segments impart a thermosensitive character to the obtained water-soluble amphiphilic hybrid block copolymers; hence they display temperature-dependent self-assembly behavior in aqueous medium. 相似文献
44.
El-Qahtani Zainab M. H. Abdel-Khalek Sayed Berrada Kamal 《Journal of Russian Laser Research》2022,43(2):139-147
Journal of Russian Laser Research - In this work, we study quantum coherence, the degree of mixedness, and total quantum correlation in two interacting superconducting charge qubits (SCQs) in both... 相似文献
45.
A synergistic catalysis combination of chiral‐at‐metal rhodium complex and amine catalyst was developed for enantioselective alkylation of aldehydes with α,β‐unsaturated 2‐acyl imidazoles. The corresponding adducts were obtained in good yields with excellent enantioselectivities (up to 99% ee). 相似文献
46.
Zainab R. Al‐Yasiri Klaus Gürlebeck 《Mathematical Methods in the Applied Sciences》2016,39(14):4056-4068
The p‐Laplace equation is a nonlinear generalization of the Laplace equation. This generalization is often used as a model problem for special types of nonlinearities. The p‐Laplace equation can be seen as a bridge between very general nonlinear equations and the linear Laplace equation. The aim of this paper is to solve the p‐Laplace equation for 1 < p < 2 and to find strong solutions. The idea is to apply a hypercomplex integral operator and spatial function theoretic methods to transform the p‐Laplace equation into the p‐Dirac equation. This equation will be solved iteratively by using a fixed‐point theorem. Applying operator‐theoretical methods for the p‐Dirac equation and p‐Laplace equation, the existence and uniqueness of solutions in certain Sobolev spaces will be proved. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
47.
Structural and Magnetic Properties of Chemically Synthesized Pd-Modified NiFe2O4 Nanoparticles 下载免费PDF全文
Magnetic nanoparticles of NiFe2O4-Pd composites have been synthesized using a simple, low cost, sol-gel auto-combustion method. As-prepared samples were sintered at 800 ℃ for 6 h in order to develop the crystalline phase. X-ray diffraction confirmed the spinel structure of the ferrite samples. Structural morphology and size of the nanoparticles were evaluated using a field emission scanning electron microscope. Magnetic hysteresis loops were obtained at 300 and 100 K using a physical properties measurement system. The value of saturation magnetization was observed to decrease at the temperatures with the increase of Pd contents up to 5% but then a sudden rise in saturation magnetization was observed for the addition of 10% Pd in NiFe2O4. 相似文献
48.
Islam Shumaila Bidin Noriah Saeed M. Alam Riaz Saira Bakar M. Aizat A. Naseem Shahzad Abbas Khaldoon Naji Sanagi Mohd Marsin 《Journal of Sol-Gel Science and Technology》2017,81(2):623-631
Journal of Sol-Gel Science and Technology - Using in-situ sol–gel processing, Sn-doped MgO2 nanofilm has been fabricated by spin-coating technique. Cracked and uneven distribution of... 相似文献
49.
Zainab Manzoor Memon Erkan Yilmaz Mustafa Soylak 《Journal of the Iranian Chemical Society》2017,14(12):2521-2528
In this method, quercetin as a flavonoid has been extracted, preconcentrated and determined by using ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction method in food samples. The quercetin concentration in extraction phase was determinated by UV–visible spectrophotometer which has microsampling cuvette. Multivariate statistical design approach was used to optimize the analytical variables including the pH, ratio of restricted access solvent components, volume of restricted access solvent, ultrasonication and centrifugation times. The analytical performance values of the developed method including limit of detection, limit of quantification, preconcentration factor and relative standard deviation (10 replicates of 10–5 M of quercetin solution) were found as 2.98, 9.93 μg L?1, 30 and 6.3%, respectively. The method provides important advantages such as use of minimum volume of organic solvents, simple and economical operation and easy optimization via multivariate statistical design approach. The developed procedure was validated with four food samples, and acceptable recoveries (87–104%) were achieved. 相似文献
50.
Pedram Fatehi Robin Singh Zainab Ziaee Huining Xiao Yonghao Ni 《European Polymer Journal》2011,(5):997-1004
The cationization of polymers has been regarded as an effective method to improve their performance for various applications. In this work, the cationization of poly vinyl alcohol (PVA) was investigated under different conditions, i.e., various glycidyl-trimethylammonium chloride (GTMAC) to PVA ratios, reaction temperatures, times, PVA and NaOH concentrations and solvent compositions. The results showed that the overall efficiency of the cationic modification was rather low, which was due to the hydrolysis of both GTMAC and cationic-modified PVA (CPVA) under the strong alkaline conditions employed. The results also showed that the optimum GTMAC/PVA ratio depended on the solvent composition. The cationization was confirmed by means of 1H NMR and FTIR analyses. The maximum efficiency in water was obtained under the conditions of 95 °C, 1 h, 0.5 (mol) GTMAC/PVA ratio, and 5% (mol) NaOH concentration, while that in the ethanol/DMSO mixture (1.25 v/v) was obtained under the conditions of 70 °C, 1 h, 0.5 (mol) GTMAC/PVA ratio, and 5% (mol) NaOH concentration. Additionally, the interaction of CPVAs with a silicon wafer (as a substrate) was determined by employing an atomic force microscope (AFM) in water and air. 相似文献