关键词：
Structure of nanocrystals and nanoparticles;Vacuum deposition;Impact phenomena;Molecular dynamics;Nanoparticle growth mechanism;Modeling and simulation
摘要：
The use of energetic particles can change the growth mode and provide control of nanoalloy morphology and properties. The impact deposition of Ni (or Al) on the truncated octahedral nanoparticle of Al (or Ni) is studied. The embedded atom method is used for the description of the interatomic interactions in combination with molecular dynamics method for the growth simulation. Three configurations of Ni–Al nanoparticle are obtained depending on incident energy and deposition sequence. A perfect core–shell nanoparticle with Ni-core/Al-shell is obtained as Al atoms are deposited over Ni nanoparticle. For the deposition of Ni atoms on Al nanoparticle, an onion-like nanoparticle at smaller incident energy, and a configuration with Al-shell and alloyed Ni–Al core at larger incident energy are observed, respectively. The formation energies show that the latter is energetically favorable.
摘要：
The combined pretreatment of rice straw using NaOH and ozone followed by enzymatic hydrolysis was investigated in comparison with NaOH pretreatment. In order to measure the composition variance, the surface morphology of rice straw was investigated by the scanning electron microscopy. The combined pretreatment of rice straw increased the specific surface area and total pore volume, which could degrade the lignin polymer, solubilize hemicellulose and neutral detergent solubles. During the combined pretreatment of rice straw using NaOH and ozone, no measurable quantity of furfural and hydroxymethyl furfural has been detected. These chemical and morphological changes of rice straw lead to the increased access of cellulase to rice straw surface and the enhanced susceptibility to enzymatic hydrolysis. The conversed percentage of cellulose and hemicelluloses presented in combined pretreated rice straw is 92.6 %, while those of NaOH pretreated and untreated rice straw are 73.8 % and 52.5 %, respectively.
作者：
Wang, Yong;Tang, Jianfeng;Ouyang, Xicheng;Liu, Buqiong*;Lin, Rong Han
期刊：
Materials Research Bulletin,2013年48(6):2123-2127 ISSN：0025-5408
通讯作者：
Liu, Buqiong
作者机构：
[Ouyang, Xicheng; Tang, Jianfeng; Wang, Yong] Hunan Agr Univ, Dept Appl Phys, Changsha 410128, Hunan, Peoples R China.;[Liu, Buqiong] Hunan Agr Univ, Dept Grad Studies, Changsha 410128, Hunan, Peoples R China.;[Lin, Rong Han] Northwestern Univ, Dept Chem, Evanston, IL 60208 USA.
通讯机构：
[Liu, Buqiong] H;Hunan Agr Univ, Dept Grad Studies, Changsha 410128, Hunan, Peoples R China.
关键词：
A. Optical materials;D. Luminescence;D. Optical properties
摘要：
The AlN-doped BaMgAl10O17:Eu2+ phosphors were synthesized by conventional solid-state reaction. Powder X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectrum (PL) were used for characterization. The growth mechanism was carried out by computer simulation with CASTEP application, and revealed that an ideal hexagonal shape, particle size in 5 μm and 2.5–3 μm in thickness, could be obtained by AlN doping. Additionally, due to the low electronegativity of N3−, the AlN-doped sample showed 35% increase in PL intensity and improvement of thermal stability. These fine particle size and better photoluminescence properties are expected to be applicable to industrial production of BaMgAl10O17:Eu2+ phosphors.
关键词：
This paper focuses on the multidirectional associative memory (MAM) neural networks with m fields which is more advanced to realize associative memory. Based on the Brouwer fixed point theorem and Dini upper right derivative;it is confirmed that the multidirectional associative memory neural network can have 3l equilibria and 2l equilibria of them are stable;where l is a parameter associated with the number of neurons. Furthermore;an example is given to illustrate the effectiveness of the results. Published: 2013 First available in Project Euclid: 14 March 2014 zbMATH: 06950768 MathSciNet: MR3138931 Digital Object Identifier: 10.1155/2013/592056
摘要：
This paper focuses on the multidirectional associative memory (MAM) neural networks with m fields which is more advanced to realize associative memory. Based on the Brouwer fixed point theorem and Dini upper right derivative, it is confirmed that the multidirectional associative memory neural network can have 3(l). equilibria and 2(l). equilibria of them are stable, where l is a parameter associated with the number of neurons. Furthermore, an example is given to illustrate the effectiveness of the results.
摘要：
In this paper, three dimensional (3D) Cu2SnS3 architectures were successfully synthesized via a simple solvothermal route. The structure, morphology and optical properties of the as-prepared samples were characterized by using an X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–vis diffuse reflectance spectra (UV–vis DRS). The SEM and TEM image indicated that the flower Cu2SnS3 architectures consist of large number of uniform nanosheets. The band gap is about 2.42 eV, which have been confirmed by UV–vis DRS. Photocatalytic activities by photodegradation reaction of methylene blue (MB) were investigated under visible-light irradiation. The results indicate the potential applications of the Cu2SnS3 architectures in visible-light-driven photocatalysts.
关键词：
Meromorphic functions;shared value;normal family;Meromorphic functions;shared value;normal family
摘要：
In this paper we study the problem of normal families of meromorphic functions concerning shared values. Let F be a family of meromorphic functions in the plane domain D subset of C and it be a positive integer. Let a, b be two finite complex constants such that a not equal 0. If n >= 3 and f + a(f')(n) and g + a(g')(n) share b in D for every pair of functions f, g is an element of F, then F is normal in D. And some examples are provided to show the result is sharp.
关键词：
continued fractions;Laurent series;partial quotient;Hausdorff dimension
摘要：
Let $\mathbb{F}_q$ be a finite field with q elements and $\mathbb{F}_q((X^{-1}))$ be the field of all formal Laurent series with coefficients lying in $\mathbb{F}_q$. This paper concerns with the size of the set of points $x{\in}\mathbb{F}_q((X^{-1}))$ with their partial quotients $A_n(x)$ both lying in a given subset $\mathbb{B}$ of polynomials in $\mathbb{F}_q[X]$ ($\mathbb{F}_q[X]$ denotes the ring of polynomials with coefficients in $\mathbb{F}_q$) and deg $A_n(x)$ tends to infinity at least with some given speed. Write $E_{\mathbb{B}}=\{x:A_n(x){\in}\mathbb{B},\;deg\;A_n(x){\rightarrow}{\infty}\;as\;n{\rightarrow}{\infty}\}$. It was shown in [8] that the Hausdorff dimension of $E_{\mathbb{B}}$ is inf{$s:{\sum}_{b{\in}\mathbb{B}}(q^{-2\;deg\;b})^s$ < ${\infty}$}. In this note, we will show that the above result is sharp. Moreover, we also attempt to give conditions under which the above dimensional formula still valid if we require the given speed of deg $A_n(x)$ tends to infinity.
关键词：
Titanium dioxide;mesoporous material;dye-sensitized solar cells
摘要：
Pure anatase TiO2 spheres with mesoporous structure were prepared by a simple urea assisted hydrothermal process at low temperature. X-ray Diffractometer, Scanning Electron Microscope, Transmission Electron Microscope, and N2 adsorption-desorption were used to characterize TiO2. The dye-sensitized solar cells results show that an overall light conversion efficiency of 6.96% which is 36.7% higher than that of the overall efficiency (5.09%) obtained from the P25 photoanode owing to the superior light scattering effect and the high level of dye loading capacity of microspheres.
摘要：
In this paper, we consider the compressible Navier-Stokes-Korteweg system that models the motions of the compressible isothermal viscous capillary fluids. We prove the global existence of a strong solution to the compressible Navier-Stokes-Korteweg system when the initial perturbation lips parallel to rho(0) - (rho) over cap parallel to(H2) + parallel to u(0)parallel to(H1) is small. Furthermore, if the L-1 norm of the initial perturbation is finite, we can obtain the optimal L-2 decay rates. (C) 2012 Elsevier Inc. All rights reserved.
摘要：
A delayed ratio-dependent predator-prey discrete-time model with nonmonotone functional response is investigated in this paper. By using the continuation theorem of Mawhins coincidence degree theory, some new sufficient conditions are obtained for the existence of multiple positive periodic solutions of the discrete model. An example is given to illustrate the feasibility of the obtained result.
关键词：
Braneworld black hole;Exact solution;Geodesic equation;Precession angle
摘要：
The exact solution to geodesic equation in the braneworld black hole spacetime is found by method of Jacobian elliptic function, and the angle of perihelion precession is obtained by the zero point of Jacobian elliptic function for Mercury. Comparing numerical result with observation data, we give the value range of tidal charge.
摘要：
The paper proposes several mathematical models of the multidirectional associative memory (MAM) neural network by analyzing its structure. A model of MAM with distributed delays is studied. Under some new assumptions on activation functions, $${2^{n_0[m/2]}}$$ invariant subsets of MAM are constructed. Then the existence and the exponential stability of $${2^{n_0[m/2]}}$$ periodic solutions located on invariant subsets are obtained by constructing a suitable Liapunov function and a Poincaré mapping. An estimating method of the exponential convergence rate is given. The obtained results are new to MAM neural networks. An example is given to illustrate the effectiveness of the results. The paper proposes several mathematical models of the multidirectional associative memory (MAM) neural network by analyzing its structure. A model of MAM with distributed delays is studied. Under some new assumptions on activation functions, $${2^{n_0[m/2]}}$$ invariant subsets of MAM are constructed. Then the existence and the exponential stability of $${2^{n_0[m/2]}}$$ periodic solutions located on invariant subsets are obtained by constructing a suitable Liapunov function and a Poincaré mapping. An estimating method of the exponential convergence rate is given. The obtained results are new to MAM neural networks. An example is given to illustrate the effectiveness of the results.
关键词：
Yeast lipid;Lignocellulosic biomass;Detoxification of hydrolyzate;Inhibition;Biodiesel
摘要：
Microbial lipid produced using yeast fermentation with inexpensive carbon sources such as lignocellulosic hydrolyzate can be an alternative feedstock for biodiesel production. Several inhibitors that can be generated during acid hydrolysis of lignocellulose were added solely or together into the culture medium to study their individual inhibitory actions and their synergistic effects on the growth and lipid accumulation of oleaginous yeast Rhodosporidium toruloides. When the inhibitors were present in isolation in the medium, to obtain a high cell biomass accumulation, the concentrations of formic acid, acetic acid, furfural and vanillin should be lower than 2, 5, 0.5 and 1.5 g/L, respectively. However, the synergistic effects of these compounds could dramatically decrease the minimum critical inhibitory concentrations leading to significant growth and lipid production inhibitions. Unlike the above-cited inhibitors, sodium lignosulphonate had no negative influence on biomass accumulation when its concentration was in the range of 0.5-2.0 g/L; in effect, it was found to facilitate cell growth and sugar-to-lipid conversion. The fatty acid compositional profile of the yeast lipid was in the compositional range of various plant oils and animal tallow. Finally, the crude yeast lipid from bagasse hydrolyzate could be well converted into fatty acid methyl ester (FAME, biodiesel) by enzymatic transesterification in a tert-butanol system with biodiesel yield of 67.2% and lipid-to-biodiesel conversion of 88.4%.
