THE MULTIBAND MIXING AND THE i(ω)

The effect for the mixing of the three-band, the g, γ and β bands, on the i(ω) is discussed. The decreasing behavior for i(ω) after some value is interpreted, and it is shown that near the crossing point (ω_c) of the s and g bands, rotation-aligned angular momentum of the quasiparticle is only a part of the total i(ω).     

THE BACKGROUND FIELD STRENGTH OF THE VACUUM WITH THE ENERGY BAND STRUCTURE

The background field strength of the vacuum with the energy band structure in a 3 dimensional sphere with a finite radius R is calculated. In general, it is not equal to zero. It tends to zero as R→∞.     

ON THE MECHANISM OF BACKBENDING PHENOMENA OF SOME EVEN-EVEN NUCLEI

The energy levels, B(E2) values and gyromagnetic ratio g of some even-even nuclei have been calculated with a double band scheme of band-crossing. Based on these results, the mechanism of backbending phenomena is analyzed, and the possible criterion to distinguish the effects of shape transition, rotation-alignment and pairing collapse are also discussed.     

THE FINE STRUCTURE OF 208Pb 1+ STATES

The energy levels and transition probabilities B（M1） of the ²⁰⁸Pb 1⁺ states are calculated using the matrix diagonalized method in which the （1p 1h） configurations are coupled to collective octupole phonons. Calculated results show that the fine structure of the ²⁰⁸Pb giant magnectic resonance depends rather strongly on the phononparticle coupling constant.     

INTERACTING BOSON MODEL FOR ROTATIONAL STATES OF NEGATIVE PARITY

In this paper, rotation of the system consiting of N—1 (sd) bosons and one (pf)boson is discussed on the assumption that the SU(3) limit is just the rotational limit.Using group-theoretical methods, we have given rotational spectra of negative parity,and have derived the analytic expressions of the reduced matrix elements of the E3transition from the v₀-band (K^π=0^-) to the ground band. In terms of the inegualityof the intensities of (sd)-(sd). interaction and (sd)-(pf) interaction, the differencebetween the parmeters of positive-parity bands and those of negative-parity bands areexplained qualitatively.     

SOME ISOSCALAR FACTORS FOR THE GROUP CHAIN SO(6) SO(5)

Some isoscalar factors for the group chain SO(6) SO(5) are calculated by using the method of reduced matrix elements and the building-up principle.     

Effect of intersite coulomb interaction on the electronic structure of the emery model

The low-energy spectrum of Fermi excitations of the three-band Emergy model has been calculated taking into account the intersite interaction. It is shown that the Coulomb interaction between oxygen and copper holes significantly renormalizes the spectrum of lower band Fermi excitations and modifies the concentration dependence of the chemical potential on the doping level.     

Indirect exciton transitions in the two-photon absorption in semiconductors

The theory of indirect two-photon exciton transitions is developed from third-order time-dependent perturbation theory. The problem is treated by introducing three different band models; a four-band, a two-band and an intermediate (three-band) model. Selection rules and numerical estimates show that the three-band model is the most favourable for this type of process. An application for the case of GaP is performed.     

CANONICAL QUANTIZATION OF GAUGE FIELDS (I)——THE YANG-MILLS FIELD

The Yang-Mills field is quantized within the canonical formalism in covariant gauges. The interaction Lagrangian of X and X', i.e. the unphysical components of A_μ, is studied. In this Lagramgian there is only one term contributing to the S matrix elements between physical states. It is the source of the breaking of the unitarity of the physical S matrix. We get the gauge compensating term by solving a simple functional differential equation. If the gauge compensating term is added to the action, the S matrix in the physical state vector space can be expressed in a form which has no couplings of physical and unphysical particles, and so the physical S matrix is gauge independent and unitary.     

One Loop PGBs Effects on tt Production in High Energy e+e- Annihilation

The Technicolor(TC)O(αm_t²/m_w²)corrections to top pair production in high energy e⁺e^－ annihilation are calculated in the one generation TC model.The analytic expressions are given for the form factor, the renormalized matrix element and its square.Numerical examples are presented for the corrections to the total cross-section ,the forward-backward asymmetry A_FB and the left-right asymmetry A_LR.We found that the corrections can reach －12.3%, －3.3% and －11.7% to the observables,A_FB and A_LR respectively for the favorable parameter values.The level of these corrections might be achieved at the next-generation linear collider(NLC).It might open a window for testing TC theory.     

COLLECTIVE EXCITATION SPECTRA IN EVEN-EVEN DEFORMED NUCLEI Ⅲ.——VARIOUS EXPANSIONS OF EXCITATION ENERGY OF GROUND BAND

The expansions of the excitation energy of the ground band in even-even deformed nucleus are discussed in the framework of our expression deduced in the previous papers. The conventional I(I+1)-expansion which is applicable to the region of low angular momenta is obtained and its radius of convergence is estimated. It can be proved that the ω₁-expansion is always convergent and hence the empirical fact that the ω_I-expansion converges better than the I(I+1)-expansion is explained satisfactorily.     

THE IBM EXPRESSIONS OF B(E2) FOR INTER REPRESENTATION TRASITIONS IN DEFORMED NUCLEI

The general one body E2 operator is used to derive the analytic expressions of B(E2) from the first β and γ bands to the ground band under the SU(3) basis.     

Non-Local Density Functional Description of Poly-Para-Phenylene Vinylene

A fully non-local exchange-correlation formalism the weighted density approximation （WDA）, has within the framework of density functional theory, known as been applied to the conjugated polymer poly-para-phenylene vinylene （PPV） and is shown to lead to a marked improvement in the agreement of theory and experiment for the electronic band structure of the conjugated polymer. In particular, some new model WDA functions are developed, which substantially increase the electronic band gap of the polymer relative to those obtained with the local density approximation and generalized gradient approximation. The calculated band gap of PPV is quantitatively or atleast semiquantitatively in agreement with the experimental data.     

基于特征级融合的多波段舰船目标识别方法

针对复杂情况下海上舰船目标单波段特征识别能力不足的问题,研究可见光、中波红外和长波红外三波段特征图像融合技术,重点解决图像融合方法中存在的算法耗时和融合策略选择的问题,提出了一种新的基于区域协方差矩阵的多波段特征级融合方法,针对可见光图像和红外图像分别设计11维和5维特征向量,协方差矩阵可以将多个特征进行融合,既保证了不同目标之间的区别性,同时又减小计算量。该方法首先利用显著性检测,快速定位图像中的目标区域,然后,针对不同波段图像设计的特征向量定义协方差阵的距离计算公式并进行匹配,通过对图像的一次遍历操作获得积分图像,在协方差计算时达到快速计算的目的,最后利用k-阶最近邻算法对多种舰船目标进行分类识别。利用实拍的3 400余张三波段舰船目标图像作为测试数据。实验主要分为两部分,首先对比单波段和三波段融合识别的识别率,验证所提出的融合方法具有更广的应用范围;然后,在计算效率上对比多种传统的像素级方法,验证采用的特征级融合在计算时间上的优势。实验结果表明,该方法可达到95.1%的识别率,单帧计算耗时约为0.5 s,在实时性和检测率方面都有明显提高。     

NUCLEON-MESON VERTEX INTERACTIONS DUE TO ONE-GLUON EXCHANGE TRANSITION POTENTIAL Vq→qqq

In this paper, the matrix elements of the nucleon-meson vertices due to one gluon exchange transition potential V_q→qqq are calculated by using the generator coordinate method. We obtain that the interaction forms of the vertices are the same as the nonrelativistic forms coming from the interactions of the nucleon field and the meson field; and the coupling constants are roughly consistent with the experimental data.     

Prebreakdown excitation of crystals at double multiphoton resonance: III. Forbidden transitions

Within the three-band model of a crystal, we calculated the probabilities of forbidden-allowed four-photon transitions between the valence band and the conduction band under conditions of two-photon resonance on the adjacent transition between two conduction bands. We show that the transformation of the electronic band spectrum under the action of high-power light of a prebreakdown intensity leads to a nonmonotonic dependence of the rate of photogeneration electron-hole pairs on the radiation intensity. We determined conditions under which a small change in the intensity in the range 10¹¹–10¹³ W/cm² leads to an increase in the generation rate of electron-hole pairs by more than an order of magnitude, which can cause an increase in the number of nonequilibrium carriers to values sufficient to trigger processes of destruction of the material.     

Prebreakdown excitation of crystals at double multiphoton resonance: II. Analysis of the effects of transformation of electronic band spectrum

The probabilities of multiphoton transitions between the valence and conduction bands at two-photon resonance on the adjacent transition between two conduction bands are calculated within the three-band model of a crystal. It is shown that, due to the effects of transformation of electronic band spectrum in the field of a strong light wave, the dependence of the multiphoton generation rate of electron-hole pairs on the light intensity j contains ranges where a small change in j leads to an increase in the generation rate of electron-hole pairs by several orders of magnitude, which may increase the number of nonequilibrium carriers to the level sufficient for initiating destruction of the material.     

Influence of magnetic quantization on the effective electron mass in Kane-type semiconductors

Summary We study the effective electron mass at the Fermi level in Kane-type semiconductors on the basis of fourth order in effective mass theory and taking into account the interactions of the conduction electrons, heavy holes, light holes and split-off holes, respectively. The results obtained are then compared to those derived on the basis of the well-known three-band Kane model. It is found, takingn-Hg_1−x Cd _x Te as an example, that the effective electron mass at the Fermi level in accordance with fourth-order model depends on the Fermi energy, magnetic quantum number and the electron spin respectively due to the influence of band nonparabolicity only. The dependence of effective mass on electron spin is due to spin-orbit splitting parameter of the valence band in three-band Kane model and the Fermi energy due to band nonparabolicity in two-band Kane model. The same mass exhibits an oscillatory magnetic-field dependence for all the band models as expected since the origin of oscillations in the effective mass in nonparabolic compounds is the same as that of the Shubnikov-de Hass oscillations. In addition, the corresponding results for parabolic energy bands have been obtained from the generalized expressions under certain limiting conditions.     

Effect of a magnetic field on the phonon-assisted two-photon absorption in semiconductors

The theory of the phonon-assisted two-photon transitions in a magnetic field is developed by means of perturbation theory. Three different band models have been introduced. The electronic transitions are defined by (i) interband-interband indirect transitions in the four-band model, (ii) interband-intraband indirect transitions in the three-band model, and (iii) intraband-intraband indirect transitions in the two-band model. These models differ from each other by the number of bands, the type of the photon matrix elements and the Landau selection rules. The result shows that by increasing the value of the magnetic field, the absorption co-efficient adopting the two-band model is strongly increased, but for a fixed value of the field the four-band model gives the largest contribution.