动力学破缺和真空自发破缺的手征SU(2)L×SU(2)R×U(1)σ模型

将SU(2)_L×SU(2)_R手征对称的σ模型推广到带电磁场情况下的手征σ模型,采用研究自恰性方程的方法研究了同时具有动力学破缺和真空自发破缺的手征SU(2)_L×SU(2)_R×U(1)σ模型,得到了考虑动力学自发破缺、真空自发破缺和电磁相互作用后,σ、π介子和核子都出现了不同的质量修正,并得到此模型中σ,π和核子以不同方式依赖于动力学破缺的具体表示.     

SU(23)大统一模型

本文构造了一个SU(23)大统一模型,并以中间统一标度M_A为输入计算了大统一标度M_G的一些可能的值.在本模型中,重子数B在规范场和Higgs部分均守恒,因此并无质子衰变发生.我们还对能量在M_A处的规范玻色子按规范群SU(3)_c×SU(3)_L×U(1)_Y进行了分类.     

SU(3)C×SU(2)I×U(1)Y复合轻子理论

假定HiggsYukawa耦合是宇称不守恒的唯一来源,通过取三代并引进超对称性,从而建立了一个SU(3)_C×SU(2)_I×U(1)_Y复合轻子理论.     

部分U(6) SU(3)的约化标量因子的代数表达式

利用不可约张量基方法和相互作用玻色子模型的解析波函数,计算得到了U(6) SU(3)简单的约化标量因子.通过应用递推关系,得到了U(6) SU(3)的[N_π×[N_p][N₁N₂]的部分约化标量因子的代数表达式.     

SU(3)L×U(1)X模型和暗物质的新的候选者

提出了一个基于SU(3)_L×U(1)_X群的弱电相互作用模型.在该模型中,每一代轻子均包含两个中性粒子.计算了新的中性轻子(N粒子)的寿命,并估计了它的质量上限,从而说明N粒子可以看作暗物质的候选者.     

IBM4中的强耦合SU(3)极限

将IBM推广应用于轻核时收IBM4.本文讨论了其中的下述群链.U(36)U₆(sd)×U₆(ST) SU₃(sd)×SU₃(S)×SU₃(T) SU₃(sdS)×SU₃(T)× O₃(J)× O₃(T)的约化、典型能说与E2跃迁,并用它对sd壳的核基态进行了分类.     

跷跷板模型中三阶中微子混合矩阵的幺正性破坏

对标准模型的一种简单扩充就是引入n个重的右手中微子且保持其SU(2)_L×U(1)_Y规范对称性. 通过对角化(3+n)×(3+n)阶中微子质量矩阵, 得到关于ν_e, ν_μ和ν_τ的有效 质量矩阵的精确的解析表达式. 结果表明, 在轻子带电弱流中出现的3×3中微子混合矩阵V必须不是严格幺正的. 如果通过跷跷板机制产生正确的轻的中微子的质量标度, 那么V的幺正性破坏的程度非常小, 几乎可以忽略. 类似的结论同样可以在第二类跷跷板模型中得到.     

能量大于10GeV的宇宙线中超硬正电子的起源

本文构造了一个SU(3)_L×U(1)模型,并把模型中的重轻子(N粒子)与黑暗物质粒子等同起来.通过引入适当的相互作用,N粒子可以发生微弱的衰变,从而解释了参量大于10GeV的宇宙线中超硬正电子的起源.     

SU3羣不可约表示直乘的分解

本文利用SU₃羣无穷小算子的对易关系,求出了SU₃羣的所有不可约U表示,并导出了SU₃羣的约化系数满足的方程。作为例子,我们计算了SU₃羣的(01)×(10),(11)×(10),(11)×(11),(30)×(11)的约化系数。     

超弦低能模型对称性的破缺

本文通过单圈辐射修正的方法,讨论了一个具有规范对称群SU(3)_C×SU(2)_L×SU(2)_R×SU(1)²的超弦低能模型在中间质量M₁处对称性的破缺.在唯象讨论的基础上,我们解决了一般超弦低能模型中存在的中微子质量问题,同时给出了软破缺参数A、m和M初值的取值范围.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.