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1.
Thermal reduction has been applied to the preparation of copper nanoparticles (Cu-NPs) using three kinds of nonionic surfactants (Triton X-100, Tween-80, and dodecylamine). The Cu-NPs were formed by decomposition of copper(II) oxalate in presence of triphenylphosphine. The effect of the surfactants on the formation of the Cu-NPs was studied via X-ray diffraction, scanning electron microscopy, energy dispersive analysis of X-rays, transmission electron microscopy, thermogravimetric differential thermal analyses, and Fourier transform infra-red spectroscopy. It is shown that the Cu-NPs have an fcc crystal structure. Depending on the surfactant used, Cu-NPs with diameters between 8 and 20 nm can be prepared. The smallest Cu-NPs (8 nm) were formed in the presence of micelles of dodecylamine (yield 49%), while the largest particles (20 nm) were obtained with Triton X-100 (yield 99%). The use of Triton X-100 results in the highest yield and most uniform Cu-NPs. 相似文献
2.
Minoo Kamrani 《Journal of Computational and Applied Mathematics》2010,234(5):1426-1434
In this paper for the approximate solution of stochastic partial differential equations (SPDEs) of Itô-type, the stability and application of a class of finite difference method with regard to the coefficients in the equations is analyzed. The finite difference methods discussed here will be either explicit or implicit and a comparison between them will be reported. We prove the consistency and stability of these methods and investigate the influence of the multiplier (particularly multiplier of the random noise) in mean square stability. From stochastic version of Lax-Richtmyer the convergence of these methods under some conditions are established. Numerical experiments are included to show the efficiency of the methods. 相似文献
3.
Ali Reza Shahidi Amin Anjomshoa Sayyed Hossein Shahidi Mehdi Kamrani 《Applied Mathematical Modelling》2013,37(10-11):7047-7061
In the present study, a nonlocal continuum model based on the Eringen’s theory is developed for vibration analysis of orthotropic nano-plates with arbitrary variation in thickness. Variational principle and Ritz functions are employed to calculate the size dependent natural frequencies of non-uniform nano-plates on the basis of nonlocal classical plate theory (NCLPT). The Ritz functions eliminate the need for mesh generation and thus large degrees of freedom arising in discretization methods such as finite element (FE). Effect of thickness variation on natural frequencies is examined for different nonlocal parameters, mode numbers, geometries and boundary conditions. It is found that thickness variation accompanying small scale effect has a noticeable effect on natural frequencies of non-uniform plates at nano scale. Also a comparison with finite element solution is performed to show the ability of the Ritz functions in fast converging to the exact results. It is anticipated that presented results can be used as a helpful source in vibration design and frequency optimization of non-uniform small scaled plates. 相似文献
4.
Salahaddin Kamrani Vahab Amiri Mosleh Kamrani Mohammed Baalousha 《Molecules (Basel, Switzerland)》2020,25(23)
Carbon dots (CDs) are a new type of nanomaterials of the carbon family with unique characteristics, such as their small size (e.g., <10 nm), high water solubility, low toxicity, and high metal affinity. Modification of CDs by Nitrogen functional groups (N-CDs) enhances their metal adsorption capacity. This study investigated the influences of pH (4, 6, and 9), ionic strength (1, 50, and 100 mM), and cation valency (Na+ and Ca2+) on the competitive adsorption of Pb to quartz and N-CD surfaces, the transport and retention of N-CDs in saturated porous media, and the capacity of N-CDs to mobilize pre-adsorbed Pb in quartz columns. Pb adsorption was higher on N-CDs than on quartz surfaces and decreased with increases in ionic strength (IS) and divalent cations (Ca2+) concentration. N-CD mobility in quartz columns was highest at pH of 9- and 1-mM monovalent cations (Na+) and decreased with decreases in pH and increases in ionic strength and ion valency. N-CDs mobilized pre-adsorbed Pb from quartz due to the higher adsorption affinity of Pb to N-CD than to quartz surfaces. These findings provide valuable insights into the transport, retention, and risk assessment of lead in the presence of carbon-based engineered nanoparticles. 相似文献
5.
A laser-based optical technique, the Interferometric Strain/Slope Rosette (ISSR) technique, was used to measure real-time deformations in welding heat-affected zones. This was accomplished by measuring simultaneously real-time in-plane strains, out-of-plane slopes and weld plate temperature from both carbon and stainless steel plates. All strain/slope results demonstrated a strong sensitivity to such welding parameters as temperature, weld length and heat input. Accuracy of the measurements was studied. The strain/slope responses were also proven to be predictable, with measured strains comparable to released strains measured by resistance strain rosette/hole-drilling and ISSR/ring-core cutting. 相似文献
6.
Saeedeh Kamrani Saeed Rasouli Heikalabad 《International Journal of Theoretical Physics》2018,57(11):3340-3358
In this paper, a unique gate is presented for the design of reversible flip-flops in quantum-dot cellular automata technology. The proposed gate is implemented with multiplexer, three-input Majority gate and XOR gate. The proposed gate has four input lines and four output lines. This gate is designed without garbage outputs. In other words, each output determines the function of each of flip-flops. The proposed structure is evaluated by the QCADesigner. The result of the simulation represents that the operations of the proposed structure is as expected and all functions are correct. Also, the evaluation results show that the proposed structure has significant improvement in area, cell numbers and delay compared to the previous structures. QCAPro tool is used to estimate energy consumption of the proposed structure. 相似文献
7.
Synthesis,characterization and application of graphene palladium porphyrin as a nanocatalyst for the coupling reactions such as: Suzuki‐Miyaura and Mizoroki‐Heck 下载免费PDF全文
The palladium(II)‐coordinated 5,10,15,20‐tetrakis‐(4‐hexyloxyphenyl)‐porphyrin as a macrocyclic palladium complex was covalently grafted to the surface of graphene oxide (denoted as GO‐CPTMS@Pd‐TKHPP). GO‐CPTMS@Pd‐TKHPP was characterized using microscopic and spectroscopic techniques for confirmation of functionalization. The synthesized catalyst was checked in the Suzuki‐Miyaura and the Mizoroki‐Heck coupling reactions. The catalyst is very easy to handle, environmentally safe and economical. Also, this catalytic system shows high catalytic activity and the yields of the products are excellent. Moreover, the suggested catalyst was reusable for five runs with no significant decrease in catalytic activity. 相似文献
8.
Sulfonic acid‐functionalized silica‐coated magnetic Fe3O4 nanoparticles were synthesized and applied as a green catalyst for an efficient and environmentally friendly ring opening of epoxides with aromatic amines in good to excellent yields with high chemoselectivity. Clean aminolysis of various aliphatic and aromatic epoxides in ethanol generates β‐hydroxyamines under mild reaction conditions. The synthesized acidic magnetic nanoparticles were recovered using a simple external magnet and successfully reused for five runs without any appreciable loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
Salahaddin Hajizadeh Khalil Farhadi Rahim Molaei Mehrdad Forough 《Journal of separation science》2020,43(13):2666-2674
A novel eco‐friendly and effective electromembrane extraction method combining high‐performance liquid chromatography with UV detection was developed for the enrichment and determination of capecitabine. Tragacanth‐silver nanoparticles conjugated gel was prepared by dissolving the tragacanth powder in synthesized silver nanoparticles solution and was used as a green membrane in electromembrane extraction. The porosity and presence of silver nanoparticles in the gel were characterized by field emission scanning electron microscopy. This new electromembrane extraction approach uses neither organic solvent nor carrier agents to extract the target analyte. The best electromembrane extraction efficiency was obtained by using 4.0 mm membrane gel thickness containing 2.5% w/v of tragacanth gum, donor phase pH = 5.0, acceptor phase pH = 3.0, applied voltage 50 V, extraction time 20 min, and agitation rate 500 rpm. During method validation under the optimized conditions, good linearity dynamic range between 1 and 500 ng/mL with the coefficient of determination (R2) = 0.998 was obtained. Limit of detection and Limit of quantitation were estimated to be 0.84 and 1.0 ng/mL, respectively. Finally, the applicability of this method in real samples was confirmed by an acceptable performance in extraction and determination of capecitabine in human plasma samples. 相似文献
10.
Convergence of a numerical scheme for SPDEs with correlated noise and global Lipschitz coefficients 下载免费PDF全文
Minoo Kamrani 《Mathematical Methods in the Applied Sciences》2016,39(11):2993-3004
The aim of this paper is to investigate the pathwise numerical solution of semilinear parabolic stochastic partial differential equations (SPDEs) with colored noise instead of the usual space–time white noise. We estimate the numerical solution in the L∞ topology by a method that takes advantages of the smoothing effect of the dominant linear operator. We consider the case the covariance operator of the forcing does not necessarily commute with the linear operator of the SPDE because of the fact that the Brownian motions are not necessarily independent. We show convergence of this method, and numerical examples give insight into the reliability of the theoretical study. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献