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331.
S.X. Lu Y.H. Tong C.S. Xu J.Y. Zhang X.W. Fan 《Journal of Physics and Chemistry of Solids》2005,66(10):1609-1613
AlN nanocrystals were prepared in organic solvent at atmospheric pressure and low temperature by the Schlenk technique. Both hexagonal and cubic AlN nanocrystals were obtained. The hexagonal nano-AlN powder possessed a wurtzite structure with a=3.124 Å, c=5.024 Å, the average grain size was about 2 nm. The lattice constant of the cubic nano-AlN was a=9.171 Å, the average grain size was about 4 nm. The structural and optical properties of the obtained AlN were analyzed. The emission related to deep-level defects was investigated by using temperature-dependent photoluminescence. 相似文献
332.
Jye -Chyl Lu Gouri K. Bhattacharyya 《Annals of the Institute of Statistical Mathematics》1990,42(3):543-559
In this article, several approaches are advanced towards the construction of bivariate Weibull models from the consideration of failure behaviors of the components of a two-component system. First, a general method of construction of bivariate life models is developed in the setting of random environmental effects. Some new bivariate Weibull models are derived as special cases and added insights are provided for some of the existing ones. In the course of model formulation in terms of the dependence structure, a new bivariate family of life distributions is constructed so as to incorporate both positive and negative quadrant dependence in the same parametric setting, and a bivariate Weibull model is obtained as a special case. Finally, some distributional properties are presented for a bivariate Weibull model derived from the consideration of random hazards. 相似文献
333.
Composite materials of YSZ (yttria-stabilized zirconia) with various Ni–Fe alloys were synthesized and evaluated as the solid oxide fuel cell (SOFC) anode using a 200-µm thick YSZ electrolyte as support and YSZ +La0.8Sr0.2MnO3 (LSM) as cathode. The single cell with the YSZ + Ni0.75Fe0.25 anode exhibited the highest performance among all the investigated cells, e.g. a peak power density of 403, 337, 218 and 112 mW/cm2 was achieved with H2 fuel at 900, 850, 800 and 750 °C, respectively. The composite anode with the Ni0.75Fe0.25 alloy also had the lowest polarization resistance of 0.55 Ω·cm2 at 800 °C among all the alloy compositions, indicating that this specific alloy offered a better anode composition than pure Ni. The possible mechanism for the improved performance of Ni with the Fe alloying addition towards H2 oxidation was discussed. 相似文献
334.
Qikeng Lu 《中国科学A辑(英文版)》1998,41(12):1248-1254
In the complex Grassmann manifold ℱ(m,n), the space of complexn-planes passes through the origin of Cm+n; the local coordinate of the space can be arranged into anm ×n matrixZ. It is proved that
is a U(m)-connection of ℱ(m,n) and its curvature form
satisfies the Yang-Mills equation. Moreover,
is an (Sum)-connection and its curvature form
satisfies the Yang-Mills equation.
Project partially supported by the National Natural Science Foundation of China (Grant No. 19631010) and Fundamental Research
Bureau of CAS. 相似文献
335.
José Luiz Boldrini Luís H. de Miranda Gabriela Planas 《Journal of Evolution Equations》2013,13(3):535-560
This article considers the issues of existence and regularity of solutions to the following doubly nonlinear differential inclusion $$\omega_t+\alpha (\omega_t)-\Delta \omega-\Delta_p{\omega} \ni f$$ where α is a maximal monotone operator in ${\mathbb{R}^2}$ and Δ p denotes the p-Laplacian with p > 2. The investigation on fractional regularity is based on the Galerkin method combined with a suitable basis for W 1,p , which we exhibit as a preliminary result. This approach also allows the obtaining of estimates in the so-called Nikolskii spaces, since it balances the interplay between the maximal monotone operator with the appearing higher order nonlinear terms. 相似文献
336.
This paper presents the experimental progress of laser-focused Cr atomic deposition and the experimental condition.The result is an accurate array of lines with a periodicity of 212.8±0.2 nm and mean full-width at half maximum as approximately 95 nm.Surface growth in laser-focused Cr atomic deposition is modeled and studied by kinetic Monte Carlo simulation including two events:the one is that atom trajectories in laser standing wave are simulated with the semiclassical equations of motion to obtain the deposition position;the other is that adatom diffuses by considering two major diffusion processes,namely,terrace diffusion and step-edge descending.Comparing with experimental results(Anderson W R,Bradley C C,McClelland J J and Celotta R J 1999 Phys.Rev.A 59 2476),it finds that the simulated trend of dependence on feature width is in agreement with the power of standing wave,the other two simulated trends are the same in the initial stage.These results demonstrate that some surface diffusion processes play important role in feature width broadening.Numerical result also shows that high incoming beam flux of atoms deposited redounds to decrease the distance between adatoms which can diffuse to minimize the feature width and enhance the contrast. 相似文献
337.
Well-ordered TiO2 nanotube arrays were prepared by electrochemical anodization of titanium in aqueous electrolyte solution of H3PO4 + NH4F at a constant voltage of 20 V for 3 h, followed by calcined at various temperatures. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and Photoluminescence (PL) were used to characterize the samples. The results showed that the as-prepared nanotube arrays before being calcined were amorphous and could transform to anatase phase at a heat treatment temperature higher than 400 °C. As the calcination temperatures increased, crystallization of anatase phase enhanced and rutile phase appeared at 600 °C. However, further increasing the calcination temperature would cause the collapse of nanotube arrays. PL intensity of the nanotube arrays annealed at 500 °C was the lowest, which was probably ascribed to better crystallization together with fewer surface defects of the nanotube arrays. 相似文献
338.
Shy-Der Lin Shuoh-Jung Liu Han-Chun Lu Hari Mohan Srivastava 《Czechoslovak Mathematical Journal》2013,63(4):969-987
The main object of this paper is to investigate several general families of hyper-geometric polynomials and their associated multiple integral representations. By suitably specializing our main results, the corresponding integral representations are deduced for such familiar classes of hypergeometric polynomials as (for example) the generalized Bedient polynomials of the first and second kinds. Each of the integral representations, which are derived in this paper, may be viewed also as a linearization relationship for the product of two different members of the associated family of hypergeometric polynomials. 相似文献
339.
W. L. Lu B. Liu T. Chen 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,77(2):257-264
In this paper, we study cluster synchronization in general
bi-directed networks of nonidentical clusters, where all nodes in
the same cluster share an identical map. Based on the transverse
stability analysis, we present sufficient conditions for local
cluster synchronization of networks. The conditions are
composed of two factors: the common inter-cluster coupling, which
ensures the existence of an invariant cluster synchronization
manifold, and communication between each pair of nodes in the same
cluster, which is necessary for chaos synchronization. Consequently, we propose a
quantity to measure the cluster synchronizability for a network with
respect to the given clusters via a function of the eigenvalues
of the Laplacian corresponding to the generalized eigenspace
transverse to the cluster synchronization manifold. Then, we discuss
the clustering synchronous dynamics and cluster synchronizability
for four artificial network models: (i) p-nearest-neighborhood graph; (ii)
random clustering graph; (iii) bipartite random graph; (iv)
degree-preferred growing clustering network. From these network models, we are to
reveal how the intra-cluster and inter-cluster links affect the cluster
synchronizability. By numerical examples, we find that for the first
model, the cluster synchronizability regularly enhances with the
increase of p, yet for the other three models, when the ratio of
intra-cluster links and the inter-cluster links reaches certain
quantity, the clustering synchronizability reaches maximal. 相似文献
340.
A systematic investigation concerned with phase stability, elastic properties, hardness and relevant electronic structure of Ni–P compounds (Ni3P, Ni12P5, Ni2P, Ni5P4, NiP, NiP2 and NiP3) was carried out using first principles calculations. The calculated results show that the Ni–P compounds have strong hardness, ranging from 7.80–14.54 GPa. Also, the hardness values gradually increase with the P content. Electronic structure analysis shows that the strong Ni–P and part of P–P hybrid orbitals play important roles in the hardness of these compounds. The calculated elastic constants indicated that the Ni3P, Ni12P5 and NiP2 phases are significantly anisotropic, the NiP and Ni2P exhibit some anisotropy, while the Ni5P4 and NiP3 show a relatively isotropic character. At last, the properties of these Ni–P compounds including lattice constants, thermodynamic stability, elastic constants Cij, bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio ν have been calculated. 相似文献