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1.
The existence of a positive solution for nonlinear fractional differential equations with integral boundary value conditions 下载免费PDF全文
Alberto Cabada Sladjana Dimitrijevic Tatjana Tomovic Suzana Aleksic 《Mathematical Methods in the Applied Sciences》2017,40(6):1880-1891
In this paper, first, we consider the existence of a positive solution for the nonlinear fractional differential equation boundary value problem where 0≤λ < 1,CDα is the Caputo's differential operator of order α, and f:[0,1] × [0,∞)→[0,∞) is a continuous function. Using some cone theoretic techniques, we deduce a general existence theorem for this problem. Then, we consider two following more general problems for arbitrary α, 1≤n < α≤n + 1: Problem 1: where , 0≤λ < k + 1; Problem 2: where 0≤λ≤α and Dα is the Riemann–Liouville fractional derivative of order α. For these problems, we give existence results, which improve recent results in the literature. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
2.
John W.Grove 《数学物理学报(B辑英文版)》2010,30(2):563-594
This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described. 相似文献
3.
A rapid, relatively sensitive, and low-cost method for the determination of water-soluble urea content in dermatological therapy products and cosmetics is proposed using a new spectrophotometric assay with water as the only extraction solvent. Spectrophotometric methods involve addition of a known excess of bromate to urea in an acid medium, followed by the determination of residual bromine and chlorine reacting with methyl orange and measurement of absorbance at 505 nm. The absorbance increases linearly with urea concentration (r = 0.9998). The systems obey Beer's law for 6 - 90 microg ml(-1). The calculated apparent molar absorbance values are found to be 4.537 x 10(3) dm(3) mol(-1) cm(-1) and the Sandell's sensitivity is 0.013 microg cm(-2). The variables affecting the rate of the reaction were investigated. The relative standard deviation for five-replication determination of 60 microg ml(-1) urea was 2.1% and the detection limit of the method is 0.34 ng ml(-1). 相似文献
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5.
Photoinduced charge separation reactions of J-aggregates coated on silver nanoparticles 总被引:2,自引:0,他引:2
Hranisavljevic J Dimitrijevic NM Wurtz GA Wiederrecht GP 《Journal of the American Chemical Society》2002,124(17):4536-4537
The photochemistry of cyanine J-aggregates on the surface of colloidal Ag nanoparticles is reported. The photochemistry is initiated through ultrafast photoexcitation of the plasmon band in Ag nanoparticles, producing an enhanced near-field that interacts with the J-aggregate monolayer. Through transient absorption spectroscopy, we show that photoexcitation of the plasmon in Ag nanoparticles leads to exciton dynamics that differ strongly from J-aggregates alone or for J-aggregate monolayers on bulk metal surfaces. Specifically, charge-separated states with a lifetime of approximately 300 ps between the J-aggregate and Ag colloid are formed. The reduction of the Ag nanoparticles is shown to be a multielectron process. 相似文献
6.
de la Garza L Saponjic ZV Dimitrijevic NM Thurnauer MC Rajh T 《The journal of physical chemistry. B》2006,110(2):680-686
Control of surface states of titanium dioxide nanoparticles using 2-(3,4-dihydroxyphenyl)ethylamine (dopamine) and 3,4-dihydrophenylacetic acid, which act as ligands to the undercoordinated surface sites (carrier traps), is demonstrated by electrochemical techniques. The deepest traps were found to be most reactive and are selectively removed by the addition of the ligands which enhances the kinetics of electron accumulation in the film. Furthermore, a shift in the Fermi level to more positive potentials was detected for electrodes modified with the negatively charged ligand (3,4-dihydrophenylacetic acid) compared to that of electrodes modified with the positively charged ligand (dopamine). The presence of the negative charge on the ligand also contributed to the underpotential of hydrogen evolution on 3,4-dihydrophenylacetic acid-modified electrodes. 相似文献
7.
We present a coupled damage-plasticity model, whose regularization is achieved through gradient enhancement of the free energy function by introducing new variables. They serve to transport the values of the inelastic variables across the element boundaries, and their gradients play regularisation role in the model. Variational formulation results in a pure minimisation problem, leading to model non-local in nature and preserving C0 interpolation order of the variables. Numerical examples illustrating the performance of the proposed model are presented. It is shown that the pathological mesh dependence is efficiently removed, together with the difficulties of numerical calculations in the softening range. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
M.L. Dubernet V. Boudon M.S. Dimitrijevic C. Joblin G. Leto P.A. Loboda N.J. Mason G. Mulas L.A. Nuñez N. Piskunov G. Rixon E. Roueff A. Ryabtsev B. Schmitt J. Tennyson N.A. Walton C.J. Zeippen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(15):2151-2159
The Virtual Atomic and Molecular Data Centre (VAMDC, http://www.vamdc.eu) is a European Union funded collaboration between groups involved in the generation, evaluation, and use of atomic and molecular data. VAMDC aims to build a secure, documented, flexible and interoperable e-science environment-based interface to existing atomic and molecular data. The project will cover establishing the core consortium, the development and deployment of the infrastructure and the development of interfaces to the existing atomic and molecular databases. It will also provide a forum for training potential users and dissemination of expertise worldwide. This review describes the scope of the VAMDC project; it provides a survey of the atomic and molecular data sets that will be included plus a discussion of how they will be integrated. Some applications of these data are also discussed. 相似文献
9.
A Nag DS Chung DS Dolzhnikov NM Dimitrijevic S Chattopadhyay T Shibata DV Talapin 《Journal of the American Chemical Society》2012,134(33):13604-13615
Colloidal semiconductor nanocrystals (NCs) provide convenient "building blocks" for solution-processed solar cells, light-emitting devices, photocatalytic systems, etc. The use of inorganic ligands for colloidal NCs dramatically improved inter-NC charge transport, enabling fast progress in NC-based devices. Typical inorganic ligands (e.g., Sn(2)S(6)(4-), S(2-)) are represented by negatively charged ions that bind covalently to electrophilic metal surface sites. The binding of inorganic charged species to the NC surface provides electrostatic stabilization of NC colloids in polar solvents without introducing insulating barriers between NCs. In this work we show that cationic species needed for electrostatic balance of NC surface charges can also be employed for engineering almost every property of all-inorganic NCs and NC solids, including photoluminescence efficiency, electron mobility, doping, magnetic susceptibility, and electrocatalytic performance. We used a suite of experimental techniques to elucidate the impact of various metal ions on the characteristics of all-inorganic NCs and developed strategies for engineering and optimizing NC-based materials. 相似文献
10.
Using the semiclassical perturbation approach, Stark broadening parameters for Kr II 469.4 nm, Ar II 476.5 nm, and Ar II 480.6
nm spectral lines have been determined. The obtained results have been used for the investigation of the role of the Stark
broadening mechanism on the mode properties of hollow cathode excited noble gas mixture lasers. It has been found that for
the He-KrII 469.4 nm laser broadening by neutral atom collisions is large enough to explain the single-mode operation of this
laser, as opposed to the He-ArII 476.5 nm laser where Stark broadening also has to be taken into account to explain this property.
Published in Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 405–407, May–June, 2006. 相似文献