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311.
Anuja Datta Subhendu K. Panda Subhadra Chaudhuri 《Journal of solid state chemistry》2008,181(9):2332-2337
ZnS nanorods doped with 0-15 mol% of Cu have been prepared by simple solvothermal process. With gradual increase in the Cu concentration, phase transformation of the doped ZnS nanorods from wurtzite to cubic was observed. Twins and stacking faults were developed due to atomic rearrangement in the heavily doped ZnS nanorods during phase transformation. UV-vis-NIR absorbance spectroscopy ruled out the presence of any impure Cu-S phase. The doped ZnS nanorods showed luminescence over a wide range from UV to near IR with peaks at 370, 492-498, 565 and 730 nm. The UV region peak is due to the near-band-edge transition, whereas, the green peak can be related to emission from elementary sulfur species on the surfaces of the nanorods. The orange emission at 565 nm may be linked to the recombination of electrons at deep defect levels and the Cu(t2) states present near the valence band of ZnS. The near IR emission possibly originated from transitions due to deep-level defects. 相似文献
312.
Tapan Saha Charugopal Chakrabarti 《Journal of Mathematical Analysis and Applications》2009,358(2):389-1233
In this paper, a delayed Holling-Tanner predator-prey model with ratio-dependent functional response is considered. It is proved that the model system is permanent under certain conditions. The local asymptotic stability and the Hopf-bifurcation results are discussed. Qualitative behaviour of the singularity (0,0) is explored by using a blow up transformation. Global asymptotic stability analysis of the positive equilibrium is carried out. Numerical simulations are presented for the support of our analytical findings. 相似文献
313.
314.
M. V. Volkov 《Algebra Universalis》2001,46(1-2):97-103
No Abstract.
Received January 2, 2000; accepted in final form August 28, 2000. 相似文献
315.
A. Ya. Silenko 《Theoretical and Mathematical Physics》2008,156(3):1308-1318
We successively apply the generalized Case-Foldy-Feshbach-Villars (CFFV) and the Foldy-Wouthuysen (FW) transformation to derive
the Hamiltonian for relativistic scalar particles in an electromagnetic field. In contrast to the original transformation,
the generalized CFFV transformation contains an arbitrary parameter and can be performed for massless particles, which allows
solving the problem of massless particles in an electromagnetic field. We show that the form of the Hamiltonian in the FW
representation is independent of the arbitrarily chosen parameter. Compared with the classical Hamiltonian for point particles,
this Hamiltonian contains quantum terms characterizing the quadrupole coupling of moving particles to the electric field and
the electric and mixed polarizabilities. We obtain the quantum mechanical and semiclassical equations of motion of massive
and massless particles in an electromagnetic field.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 156, No. 3, pp. 398–411, September, 2008. 相似文献
316.
利用小波分析预测方法对金融数据—股票收盘价这一典型的非平稳时间序列进行预测.使用M a llat小波分解算法对数据进行分解,对分解后的数据进行平滑处理,然后再进行重构,而重构之后的数据就成为近似意义的平稳时间序列,这样就得到了原始数据的近似信号,再应用传统时间序列预测方法对重构后的数据进行预测,将预测结果与实际值,以及和传统预测方法预测结果比较,小波分析方法预测效果更为理想. 相似文献
317.
In this paper,let T be a bounded linear operator on a complex Hilbert H.We give and prove that every p-w-hyponormal operator has Bishop's property(β)and spectral properties;Quasi-similar p-w-hyponormal operators have equal spectra and equal essential spectra.Finally,for p-w-hyponormal operators,we give a kind of proof of its normality by use of properties of partial isometry. 相似文献
318.
X. R. Ma 《Proceedings of the American Mathematical Society》2005,133(11):3179-3189
We present a necessary and sufficient condition for two matrices given by two bivariate functions to be inverse to each other with certainty in the cases of Krattenthaler formula and Warnaar's elliptic matrix inversion. Immediate consequences of our result are some known functions and a constructive approach to derive new matrix inversions from known ones.
319.
M. Van Barel E. Van Camp N. Mastronardi 《Numerical Linear Algebra with Applications》2005,12(10):981-1000
Very recently, an algorithm, which reduces any symmetric matrix into a semiseparable one of semi‐ separability rank 1 by similar orthogonality transformations, has been proposed by Vandebril, Van Barel and Mastronardi. Partial execution of this algorithm computes a semiseparable matrix whose eigenvalues are the Ritz‐values obtained by the Lanczos' process applied to the original matrix. Also a kind of nested subspace iteration is performed at each step. In this paper, we generalize the above results and propose an algorithm to reduce any symmetric matrix into a similar block‐semiseparable one of semiseparability rank k, with k ∈ ?, by orthogonal similarity transformations. Also in this case partial execution of the algorithm computes a block‐semiseparable matrix whose eigenvalues are the Ritz‐values obtained by the block‐Lanczos' process with k starting vectors, applied to the original matrix. Subspace iteration is performed at each step as well. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
320.
Two-dimensional (2D) nano-objects, such as metallic nanofilms are the most fundamental building blocks for nanoelectronics devices. However, the fabrication of highly ordered nanofilms has been difficult because of well known Stranski-Krastanov growth, which results in rough growth front and high density grains. Here we report on the unusual high-quality film growth of Bi on a Si surface with atomic-level surface/interface smoothness and high film crystallinity. The formation of a newly discovered 2D allotrope was clarified to initiate its strong 2D growth. Above several-monolayer thickness, the 2D allotrope transforms into a single-crystalline film with bulk-like layered structure. Our study unveils the atomistic growth process of nano-sized Bi, and the obtained knowledge here will be generally applicable for the fabrication of various nano-devices using this intriguing material that shows rich thermal, magnetic, electronic properties in nanometer scale. 相似文献