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101.
Because of its unique optoelectronic properties,people have studied the characteristics of polarons in various quantum well(QW)models.Among them,the asymmetrical semiexponential QW(ASEQW)is a new model for studying the structure of QWs in recent years.It is of great significance to study the influences of the impurity and anisotropic parabolic confinement potential(APCP)on the crystal’s properties,because some of the impurities,usually regarded as Coulomb’s impurity potential(CIP),will exist in the crystal more or less,and the APCP has flexible adjustment parameters.However,the energy characteristics of the ASEQW under the combined actions of impurities and APCP have not been studied,which is the motivation of this paper.Using the linear combination operation and Lee-Low-Pines unitary transformation methods,we investigate the vibrational frequency and the ground state energy of the strong coupling polaron in an ASEQW with the influences of the CIP at the origin of coordinates and APCP,and make a comparison between our results and previous literature’s.Our numerical results about the energy properties in the ASEQW influenced by the CIP and APCP may have important significances for experimental design and device preparation. 相似文献
102.
The total amplitude reflection coefficient of EM wave in a nonuniform plasma slab coated on perfect conductor plane is newly derived by using the scattering matrix method (SMM), and the attenuation is calculated. Three types of plasma electron density profile, that is the hyperbolic, sinusoidal, and linear profiles, are used. The external magnetic field and plasma parameters such as the maximum electron density and collision frequencies are discussed to calculate the attenuation of EM wave. The calculation results show that the plasma electron density profile and maximum electron density exert a large effect to the attenuation of EM wave and the attenuation under the uniform external magnetic field is taken place by the electron cyclotron resonance absorption, the up hybrid resonance absorption and geometric resonances absorption. 相似文献
103.
Wu Shi Yu 《Transport in Porous Media》1987,2(2):103-127
This paper deals with the flow through a layered medium that has alternate sand and clay strata. The solutions of plane, axisymmetric and spatial cases are given. Research results in this paper can be applied to seepage calculations and hydraulic engineering designs in flood areas and reclaimed marsh land.List of Symbols
A
n
Upward leakage factor of the nth sand stratum
-
A
n
Downward leakage factor of the nth sand stratum
- [B]
Matrix of eigenvector
-
B
nm
Element of [B] corresponding to the nth sand stratum and the mth eigenvalue
-
C
m
, C
N+m
Arbitrary constants belonging to the terms contained the mth eigenvalue
- Cmj
Arbitrary constant belonging to the term contained the mth eigenvalue due to a line source in the jth sand stratum
- [D]
Inverse matrix of [B]
-
d
f0
sup+
Additional length of the seepage path for ditches in symmetric flow
-
F,
F
m
Area and dimensionless area corresponding to the mth eigenvalue (
F
m
=
fm
sup2
F)
-
f
0
Coefficient of additional resistance of partially penetrating well
-
H
Total water head; upstream water head
-
h, h
n
Water head and water head of the nth sand stratum
-
h
nj
Water head of the nth sand stratum due to a line source in the jth sand stratum
-
h
0
Surface water head
-
h/H × 100%
Potential
-
i, j
Number
-
k, k
Permeability coefficient of the sand stratum and clay stratum, respectively
-
k
n
, k
n
Permeability coefficient of the nth sand stratum and the nth clay stratum, respectively
-
L
Length
-
m
Number
-
N
Total number of sand or clay strata
-
n
Number
-
Q
j
Discharge of a line source distributed along a vertical line in the jth sand stratum
-
Q
ji
The partial discharge of the ith well (or line source), which flows through the screen pipe penetrating the jth sand stratum
-
qj
Discharge of a face source distributed on an area - unit breadth multiplied by the thickness of the jth sand stratum. The abbreviation is: unit discharge of a face source in the jth sand stratum
-
qji
Unit discharge of a face source on the ith surface element in the jth sand stratum
-
R
Constant radius
-
S
Distance; length of a curve
-
S
m
Dimensionless length of a curve corresponding to the mth eigenvalue (
S
m
=
m
S)
-
s
Number
-
T
n
, T
n
Thickness of the nth sand stratum and the nth clay stratum, respectively
-
t
Number; thickness
-
x, y, z
Cartesian coordinates
-
y
Polar coordinate; radius; distance
-
y
m
Dimensionless distance corresponding to the mth eigenvalue (
y
m
=
m
y)
-
y
0
Radius of well
-
y
0
Radius of equivalent completely penetrating well
-
Infinitesimal half breadth
-
Infinitesimal area
-
Angle
-
Eigenvalue 相似文献
104.
Wen‐Zuo Li Jian‐Bo Cheng Qing‐ Zhong Li Bao‐An Gong Jia‐Zhong Sun 《International journal of quantum chemistry》2010,110(10):1857-1862
The HBeN? and HNBe? anions have been investigated for the first time using the CASSCF, CASPT2, and DFT/B3LYP methods with the contracted atomic natural orbital (ANO) and cc‐pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized at the CASSCF/ANO and B3LYP/cc‐pVTZ levels. The ground and the first excited states of HBeN? are predicted to be X2Π and A2Σ+ states, respectively. It was predicted that the ground state of HNBe? is X2Σ+ state. The A2Π state of HNBe? has unique imaginary frequency. A bend local minimum M1 was found along the 12A″ potential energy surface and the A2Π state of HNBe? should be the transition state of the isomerization reactions for M1 ? M1. The CASPT2/ANO potential energy curves of isomerization reactions were calculated as a function of HBeN bond angle. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 相似文献
105.
本文讨论一类非线性Schrdinger方程-ε~2△v+V(z)v=K(x)v~p,x∈R~N,v∈W~(1,2)(R~N),v(x)>0,势函数V(x)有正下界和在无穷远处为零两种情形.通过强最大值原理我们证明方程的基态解关于充分小的ε>0一致集中. 相似文献
106.
107.
Sensitization in 5XXX aluminum alloys is an insidious problem characterized by the gradual formation and growth of beta phase (Mg2Al3) at grain boundaries, which increases the susceptibility of alloys to intergranular corrosion (IGC) and intergranular stress-corrosion cracking (IGSCC). The degree of sensitization (DoS) is currently quantified by the ASTM G67 Nitric Acid Mass Loss Test, which is destructive and time consuming. A fast, reliable, and non-destructive method for rapid detection and the assessment of the condition of DoS in AA5XXX aluminum alloys in the field is highly desirable. In this paper, we describe a non-destructive method for measurements of DoS in aluminum alloys with an electromagnetic acoustic transducer (EMAT). AA5083 aluminum alloy samples were sensitized at 100 °C with processing times varying from 7 days to 30 days. The DoS of sensitized samples was first quantified with the ASTM 67 test in the laboratory. Both ultrasonic velocity and attenuation in sensitized specimens were then measured using EMAT and the results were correlated with the DoS data. We found that the longitudinal wave velocity was almost a constant, independent of the sensitization, which suggests that the longitudinal wave can be used to determine the sample thickness. The shear wave velocity and especially the shear wave attenuation are sensitive to DoS. Relationships between DoS and the shear velocity, as well as the shear attenuation have been established. Finally, we performed the data mining to evaluate and improve the accuracy in the measurements of DoS in aluminum alloys with EMAT. 相似文献
108.
109.
HL-2Aװ����CXRS��ϵ�ϵͳ��� 总被引:2,自引:0,他引:2
为了获取HL-2A等离子体的离子温度、旋转速度及其分布等重要参数,首次在HL-2A装置上开展了CXRS诊断。通过利用能有效探测微弱光的EMCCD和特殊设计的光学采集系统,获得了具有足够信噪比的诊断信号。实验得到的测量信号分析表明,设计是切实可行的。 相似文献
110.
We investigate the effect of geometry on the ground-state ordering of artificially frustrated magnetic rectangular and triangular lattices by Monte Carlo method. By varying the vertical lattice spacing while keeping the horizontal one fixed, we show that when the ratio of vertical to horizontal lattice spacing, labeled by η, is less than 1.82, the ground state of the rectangular lattice presents long-range antiferromagnetic order and for η?1.82 the ground state changes to long-range mixed ferromagnetic and antiferromagnetic order. For the frustrated triangular lattice, the short-range ordered state as well as two long-range ordered ground states occurs transiently at η=0.87 and 2, where the energies of the two ground states with long-range order are approximately equal. In addition, the level of frustration of both frustrated lattices is found to be largely relevant to the ratio η. 相似文献