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941.
WuBing Yang FengGan Zhuang Qing Shen FaMing Guan Qiang Wang ShiHe Yi YuXin Zhao Lin He LiFeng Tian 《中国科学G辑(英文版)》2009,52(10):1624-1631
The parameters of instability wave of supersonic mixing layer(Mc=0.5,M1=3.5/M2=1.4) are measured by flow visualization and calculated by means of two-dimensional direct numerical simulaitons of the compressible Navier-Stokes equations.In both cases of the mixing layer with harmonic disturbance or not,the comparative results indicate that the wavelength of the two-dimensional wave is equal to the vortex spacing in the streamwise direction because the difference between them is less than 1%.However,the measur... 相似文献
942.
利用太赫兹时域光谱(THz-TDS)系统,在5—300 K温区下测量了在厚度约200 nm的金属Nb薄膜刻蚀的亚波长圆孔阵列的异常THz波透射情况.实验结果表明,在03—2 THz波段,具有亚波长孔阵结构的金属Nb薄膜的异常透射现象波谱的峰位置与CST(computer simulation technology)软件仿真模拟的结果一致,峰值随温度降低有逐渐增强的趋势.
关键词:
亚波长孔阵列
THz时域光谱技术
异常透射 相似文献
943.
基于最低未被占据分子轨道(LUMO)和最高被占据分子轨道(HOMO)的高斯态密度分布与载流子在允许量子态中的费米-狄拉克(Fermi-Dirac)分布,提出有机半导体中物理掺杂的理论模型;研究了掺杂浓度、温度和禁带宽度对载流子浓度的影响,并与一些报道的实验结果做了比较.研究发现无论是否掺杂,温度升高时,有机半导体中的载流子浓度都会增大,并且随温度倒数的线性减小而指数增大;对于本征有机半导体,载流子浓度随禁带宽度的增大而指数下降,随高斯分布宽度的平方指数增加;对杂质和主体不同能级关系的掺杂情形下掺杂浓度对载
关键词:
有机半导体
掺杂
高斯态密度
载流子浓度 相似文献
944.
4fN-15d energy levels of lanthanides: aquasi-angular-momentum approach and its application to Cs2NaYF6:Er3+ 下载免费PDF全文
<正>The spin-orbit interaction of the 5d electron needs to be taken into account to give the proper energy structure for the 4fN-15d configuration of heavy lanthanide ions occupying a site with ligands forming an octahedron.This paper derives theoretical results for the energy structure by treating the t2 orbitals as quasi p orbitals and then using angular-momentum coupling techniques.An analytic expression for the electric dipole absorption line strengths between 4fN multiplets and 4fN-15d states is given in terms of various angular-momentum quantum numbers and re-coupling coefficients.The result is then applied to interpret the excitation spectrum of Cs2NaYF6:Er3+.The high-spin and low-spin states of Cs2NaYF6:Er3+ are discussed in terms of the wavefunctions obtained by using the developed theoretical model. 相似文献
945.
Dragan Mašulović 《Order》2007,24(4):215-226
A structure is called homogeneous if every isomorphism between finite substructures of the structure extends to an automorphism
of the structure. Recently, P. J. Cameron and J. Nešetřil introduced a relaxed version of homogeneity: we say that a structure
is homomorphism-homogeneous if every homomorphism between finite substructures of the structure extends to an endomorphism
of the structure. In this paper we characterize homomorphism-homogeneous partially ordered sets (where a homomorphism between
partially ordered sets A and B is a mapping f : A →B satisfying ). We show that there are five types of homomorphism-homogeneous partially ordered sets: partially ordered sets whose connected
components are chains; trees; dual trees; partially ordered sets which split into a tree and a dual tree; and X
5-dense locally bounded partially ordered sets.
Supported by the Ministry od Science and Environmental Protection of the Republic of Serbia, Grant No. 144017. 相似文献
946.
Ji-pu Ma Tseng Yaun Rong Functional Analysis Research Center Harbin Normal University Harbin China 《中国科学A辑(英文版)》2007,50(9):1233-1239
Let E, F be two Banach spaces, and B(E, F), Φ(E, F), SΦ(E, F) and R(E,F) be the bounded linear, Fredholm, semi-Frdholm and finite rank operators from E into F, respectively. In this paper, using the continuity characteristics of generalized inverses of operators under small perturbations, we prove the following result Let ∑ be any one of the following sets {T ∈ Φ(E, F) IndexT =const, and dim N(T) = const.}, {T ∈ SΦ(E, F) either dim N(T) = const. < ∞ or codim R(T) = const.< ∞} and {T ∈ R(E, F) RankT =const.<∞}. Then ∑ is a smooth submanifold of B(E, F) with the tangent space TA∑ = {B ∈ B(E,F) BN(A) (∪) R(A)} for any A ∈ ∑. The result is available for the further application to Thom's famous results on the transversility and the study of the infinite dimensional geometry. 相似文献
947.
采用磁化等离子体的分段线性电流密度卷积时域有限差分(PLCDRC-FDTD)算法研究具有单一缺陷层的一维磁化等离子体光子晶体的缺陷模特性. 从频域角度分析得到微分高斯脉冲的透射率,并讨论该光子晶体的缺陷层厚度、位置、周期常数和等离子体参数对其缺陷模的影响. 结果表明,改变位置和周期常数不会影响缺陷模的频率,改变缺陷层的厚度可以增加缺陷模数,改变等离子体参数能同时影响缺陷模的频率和峰值.
关键词:
磁化等离子体光子晶体
光子晶体
缺陷模
时域有限差分法 相似文献
948.
Four-mode continuous-variables entangled state: generation from beam splitter, a parametric down-conversion and a polarizer 下载免费PDF全文
We introduce a new kind of four-mode continuous variable entangled
state in Fock space. The completeness relation and the partly
nonorthonormal property of such a state are proven. The scheme to
generate this state is presented by combining a symmetrical
beamsplitter, a parametric down-conversion and a polarizer. After
making a single-mode quadrature amplitude measurement, the remaining
three modes are kept in entanglement. And its applications are also
discussed. 相似文献
949.
Simulation study on terahertz vibrational absorption in liquid crystal compounds 总被引:1,自引:0,他引:1 下载免费PDF全文
The terahertz (THz) spectrum absorptions of nematic liquid crystal
(LC) material, i.e. N-(p-methoxybenzylidene)-p-butylaniline (MBBA),
and its relevant compounds are simulated in this paper by using the
density functional theory (DFT) method. A strong absorptive
frequency is located at 3.65 THz for the MBBA, which is in
agreement with experimental data found in the literature. The result
suggests that the DFT method is effective for dealing with the
anisotropic nematic LC compounds. 相似文献
950.
Robust stability analysis for Markovian jumping stochastic neural networks with mode-dependent time-varying interval delay and multiplicative noise 下载免费PDF全文
This paper is concerned with the problem of robust stability for a
class of Markovian jumping stochastic neural networks (MJSNNs)
subject to mode-dependent time-varying interval delay and
state-multiplicative noise. Based on the Lyapunov--Krasovskii functional
and a stochastic analysis approach, some new delay-dependent
sufficient conditions are obtained in the linear matrix inequality
(LMI) format such that delayed MJSNNs are globally asymptotically
stable in the mean-square sense for all admissible uncertainties. An
important feature of the results is that the stability criteria are
dependent on not only the lower bound and upper bound of delay for all
modes but also the covariance matrix consisting of the correlation
coefficient. Numerical examples are given to illustrate the
effectiveness. 相似文献