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71.
In this article, we propose a numerical scheme to solve the one‐dimensional undamped Sine‐Gordon equation using collocation points and approximating the solution using Thin Plate Splines (TPS) radial basis function (RBF). The scheme works in a similar fashion as finite difference methods. The results of numerical experiments are presented and are compared with analytical solutions to confirm the good accuracy of the presented scheme.© 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008 相似文献
72.
The iminium intermediate formed by the reaction of a secondary amine with acetaldehyde was reacted by (N‐isocyanimino) triphenylphosphorane in the presence of an electron‐poor (E)‐cinnamic acid derivative to give the corresponding iminophosphorane intermediate, whose intramolecular the aza‐Wittig reaction led to disubstituted 1,3,4‐oxadiazole derivatives. The reactions were completed under neutral conditions at room temperature, and the corresponding disubstituted 1,3,4‐oxadiazole derivatives were produced in excellent yields. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 22:79–84, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20660 相似文献
73.
In this research, we report on the characterization of La1?xTbxMn0.9Zn0.1O3+d (LTMZ) (0.0≤x≤0.32). Nanoparticles with high surface area were synthesized by the polymerized complex method based on the Pechini-type reaction. High-quality nanopowders with controlled stochiometry and microstructure were prepared in the temperature range of 700–800 °C for 6 h, with mean particle sizes of approximately 18.35 nm. The synthesized materials were characterized by X-ray powder diffraction, fourier transform infrared spectrometry and photoluminescence (PL). PL measurements showed the characteristic green emission of Tb3+ ions in crystalline LTMZ powders due to the 5D 4→7F J transitions of the 4f electrons of Tb3+ ions. The structure, homogeneity and particle size of the obtained compounds during different stages were investigated by scanning electron microscopy. 相似文献
74.
Abdouss Majid Shokri Aref Karimi Mohammad Mehdi Zargaran Mojdeh 《Russian Journal of Applied Chemistry》2022,95(3):366-378
Russian Journal of Applied Chemistry - In this project, the fibers were applied to increase the tensile strength of the concrete and produce fiber reinforced concrete (FRC). Polypropylene (PP) is... 相似文献
75.
JPC – Journal of Planar Chromatography – Modern TLC - A simple and highly sensitive method is developed for the determination of streptomycin in dosage forms and in biological fluids... 相似文献
76.
Kinetic,Equilibrium and Isotherm Studies of Cadmium Removal from Aqueous Solutions by Oxidized Multi‐Walled Carbon Nanotubes and the Functionalized Ones with Thiosemicarbazide and Their Toxicity Investigations: A Comparison 下载免费PDF全文
The multi‐walled carbon nanotubes (MWCNTs) were first oxidized by nitric acid to form a MWCNT‐COOH. Then, it was modified with thiosemicarbazide to produce MWCNT‐semi. Thus, these carbon materials, MWCNTs, MWCNT‐COOH and MWCNT‐semi, have been used as efficient adsorbents for the removal of cadmium from aqueous solutions. The influence of variables including pH, concentration of the cadmium, amount of adsorbents and contact time was investigated by the batch method. The kinetic studies carried out using different kinetic models such as pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion models. The sorption process with each adsorbent was well described by pseudo‐second‐order kinetics which it was agreed well with the experimental data. The values of regression coefficient of various adsorption isotherms like Langmuir, Freundlich and Tempkin to obtain the characteristic parameters of each model have been carried out. The results showed which the Langmuir isotherm for all adsorbents and Tempkin model for MWCNT‐COOH and MWCNT‐semi was found to best represent the measured sorption data. Toxicity of these samples was evaluated in human embryonic kidney HEK293 and human breast cancer SKBR3 cell lines after culturing cells for 24 h. Cellular investigations showed that the modified MWCNTs in particular MWCNT‐semi have considerably significant toxic impact on SKBR3 as compared to HEK293 at concentration 3 µg/mL. 相似文献
77.
Several new monocyclic β-lactam monomers bearing the NO2 group 2a–g were synthesized via a [2 + 2] ketene–imine cycloaddition reaction (Staudinger reaction). Calculation of coupling constant of H-3 and H-4, and the X-ray crystallography of β-lactam 2e confirmed the cis stereochemistry of these β-lactams. Then aminophenyl β-lactams were synthesized by the reduction of NO2 to NH2 group in the presence of Raney Ni and hydrazine hydrate. Treatment of these aminophenyl β-lactams with acryloyl chloride and sodium bicarbonate (NaHCO3), afforded the monomers bearing the NHCOCH=CH2 group. These acrylated β-lactam monomers were dissolved in a warm mixture of butyl acrylate and styrene and then were converted to the corresponding polyacrylate nano β-lactams by emulsion polymerization in water. A unique feature of this methodology is the ability to incorporate water-insoluble compounds directly into the nanoparticle framework. Structures of the synthesized compounds were confirmed by physical and spectral analyses. Dynamic light scattering analysis and transmission electron microscopy of the final emulsions show that the nanoparticles were about 50–70 nm in diameter. 相似文献
78.
Hassan Kaatuzian Hossein Shokri Kojori Ashkan Zandi Masoud Ataei 《Optical and Quantum Electronics》2013,45(9):947-959
In this paper we investigate the effects of quantum well size changes on slow light device properties. The principle properties such as center frequency and slow down factor of a slow light device are affected by changing the size of quantum well. In this way, the effects of quantum well size on Oscillator Strength and binding energy of exciton are considered separately. First, we investigate the variations in oscillator strength of exciton due to different quantum well size. Second, exciton binding energy level shift due to size of quantum well is investigated. According to this analysis, we have developed a new method for tuning slow light device bandwidth center frequency and slow down factor. Analysis and simulation of a basic GaAs/AlGaAs quantum wells optical slow light device based on excitonic population oscillation shows that size of quantum wells could tune both of the frequency properties and slow down factor of an optical slow light device. Simulation results show that slow down factor and oscillation strength of exciton are proportional to each other in direct manner. Moreover, decreasing the quantum well width, causes enhancement in binding energy of excitons. These achievements are useful in optical nonlinearity enhancements, all-optical signal processing applications and optical communications. 相似文献
79.
Maryam Ciyabi Hashjin Roghayeh Ciyabi Maryam Baharloui Nava Taherizadeh Ghaffar Hosseini 《Research on Chemical Intermediates》2014,40(8):2811-2822
In this work, two new aerobic routes are introduced for the oxidation of a variety of benzoins to benzils by using molecular oxygen in the presence of porphyrins as sensitizers, using white light or sunlight in acetonitrile under mild conditions. The methods have a wide range of applications, do not involve cumbersome work-up, exhibit chemoselectivity and proceed under mild reaction conditions. The resulting products are obtained in good yields in a reasonable time. 相似文献
80.
Recently, there has been an increasing interest in the study of initial boundary value problems for Korteweg–de Vries (KdV)
equations. In this paper, we propose a numerical scheme to solve the third-order nonlinear KdV equation using collocation
points and approximating the solution using multiquadric (MQ) radial basis function (RBF). The scheme works in a similar fashion
as finite-difference methods. Numerical examples are given to confirm the good accuracy of the presented scheme. 相似文献