EFFECTIVE POTENTIAL OF λφ41+3 AT ZERO AND FINITE TEMPERATURES

The effective potential of λφ⁴₁₊₃ model with both signs of parameter m² is evaluated at T=0 by means of a simple but effective method for regularization and renormalization. Then at T≠0, the effective potential is evaluated in imaginary time Green function approach, using the Plana formula. A critical temperature for restoration of symmetry breaking in the standard model of particle physics is estimated to be T_c≌510 GeV.     

RESEARCH AND TECHNICAL NOTES ULTRASONIC ATTENUATION IN α-LiIO_3 SINGLE CRYSTAL AT LOW TEMPERATURES

Ultrasonic attenuation in an α-LiIO_3 single crystal has been measured in the [001],[010] and[100] directions at low temperatures by using the standard pulse echo method.It is clear thatultrasonic attenuation anisotropy exists in α-LiIO_3 above 273 K and disappears below 273 K.     

ANALYSIS TO THE EFFECTIVE DEPTH OF ACOUSTIC CAVITY OF COMBUSTION CHAMBER USING FINITE ELEMENT METHOD

The boundary problem of finite element method in solving the sound vibration of cavities with openinghas been studied.A theoretical formula for calculating the effective depth of acoustic cavities with differentshapes of entries was worked out and it is shown that the calculated depths agree well with those obtained bymeasurements.     

FREQUENCY AND EFFICIENCY OF SOUND COLUMN AT RESONANCE

In this paper,the resonant frequency of the sound column is investigated both theoretically andexperimentally,and the efficiency of the sound column at resonant frequency is also calculated.It isshown that the resonant frequency varies linearly with the number N of the loudspeakers in the soundcolumn,and the efficiency of the sound column at resonant frequency is directly proportional to thenumber N of the loudspeakers if N≤3,and it tends to increase more slowly if N>4. We have also proved that the radiation of the loudspeakers treated in accordance with theradiation of a plane piston on the terminal of the long tube in the sound column is in fairly goodagreement with the results of the experiment.     

SUPERCONDUCTING TRANSITION TEMPERATURES AND NORMAL-STATE ELECTRICAL RESISTIVITIES OF Tm1-xPrxBa2Cu3O7-δ

Superconducting transition temperature T_c and normal-state electrical resistivities ρ of the Tm_1-xPr_xBa₂Cu₃O_7-δ system have been measured. The results indicate that T_c remains constant for x = 0 to 0.08 before it drops steadily with higher x. Following the Abrikosov-Gor'kov model, a total suppression of superconductivity occurs at a critical Pr concentration x_cr≈0.56. It is found for the first time, as far as we know, that the logarithmic resistivity at 270 K increases linearly with increasing x, yielding ρ= ρ₀e^ax. Judging from the relation between dρ/dT and x, a metal to insulator transition occurs just beyond x_cr.     

SYNERGETIC MITIGATION OF THE RAYLEIGH—TAYLOR INSTABILITY BY SHEAR AXIAL FLOWS AND FINITE LARMOR RADIUS

1　IntroductionImplodingZ pinchesemployinggaspuffs,cy lindricalfoils,andwirearraysareverycompactandefficientdevicesforcouplingelectromagneticenergyfromapulseforminglineintoadenseplas macolumn.Morerecently,aluminumwirearrayimplosionshaveproducedthehighestX raypowerof40TWonthe20TWSaturnacceleratoratSandiaNationalLaboratory[1].Thesedeviceshavepoten tialapplicationstocontrolledfusionaswellastointensesourcesofkeVX raysfornuclearweaponseffects.Unfortunately,theimplosionsarehighlysusceptibletoR…     

STRUCTURES AND INTERNAL MOTION OF A Ne_3 CLUSTER

ＳＴＲＵＣＴＵＲＥＳＡＮＤＩＮＴＥＲＮＡＬＭＯＴＩＯＮＯＦＡＮｅ３ＣＬＵＳＴＥＲＸｉｅＷｅｎｆａｎｇＣｈｅｎＣｈｕａｎｙｕＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＧｕａｎｇｚｈｏｕＴｅａｃｈｅｒｓ′ｃｏｌｅｇｅＧｕａｎｇｚｈｏｕ５１０４００ＡＢＳＴ...     

APPLICATION OF CORRELATION—POLARIZA TION POTENTIAL TO THE LOW—ENERGY ELECTRON SCATTERING WITH ATOMS AND MOLECULES

Applicability of the correlation potential,which is currently used in the local density functional theory,to the low-energy electron-atom and molecule scattering is investigated with some examples of scattering processes.     

OBSERVATION OF PHOTOREFRACTIVE EFFECT OF KNbO3 CRYSTAL AT μW ILLUMINATION

The photorefractive effects of the as-grown and proton-implanted KNbO₃ crystals were studied by two-wave mixing at 62.2μW/cm² illumination. At this pump power level, the as-grown crystal showed little photorefractive effect, while the proton-implanted crystal showed an obvious effect. Furthermore, there seemed to exist two photorefractive gratings with response times of 22.54 and 1596.30s, at 62.2μW/cm² pump power level, in the proton-implanted sample. This phenomenon has been attributed to the influence of proton-implantation.     

THE QUARK CLUSTER MODEL OF NUCLEAR FORCE:(Ⅰ) EXPONENTIAL QUARK CONFINEMENT POTENTIAL AND NON-STRANGE BARYONIC SPECTRUM

In this paper it is assumed that the quark-quark two-particle interaction is the Coulomb-like plus exponentially rising confinement potential.The non-strange baryonic spectrum below 2 GeV has been studied consistently by the potential.The calculated position of the resonanees and the predicted mixing angles are in good agreement with experiments. It is shown that the potential can describe successfully the properties of all the low-lying non-strange baryon states.The contribution of the spin-orbit coupling force to the spectrum has also been discussed.     

THERMODYNAMICAL PROPERTIES OF GAUGE THEORIES AT FINITE TEMPERATURE AND CHEMICAL POTENTIAL

The plasma effects of gauge theories are investigated and the one-loop contributions to self-energy part of the photon at T≠0 and μ≠0 are calculated. It is shown that only electric fields give photon an effective mass, but magnetic fields don's contribute.     

FINITE TEMPERATURE EFFECTIVE POTENTIAL AND COSMOLOGICAL INFLATION IN WEINBERG-SALAM MODEL

The finite temperature effective potential in SUSY Weinberg-Salam model, proposed by Sohnius, is calculated. The temperature of the phase transition is found approximately. The scale of this temperature is of the order of hiqqs mass, it is the same as that in standard model. There is no influence on the phase transition from the Slavnov term. The cosmological inflationt SU(2)×U(1)epoch in such a model is estimated.     

PATH INTEGRAL IN CORRELATED EIGENSTATE BASIS OF COMPLEX SCALAR FIELDS φ(x) AND φ?(x)

Using the technique of integration within an ordered product of operators, we construct a new common eigenvector set of the complex scalar fields φ(x) and φ^?(x), which is a set of particle-antiparticle correlated states. On the basis of the new eigenstates we develop the path integral formuation. The new eigenvectors' properties are investigated, they are qualified to be a new representation.     

RESOLUTION OF PUZZLES IN PERTURBATION CALCULATION IN QUANTUM FIELD THEORY AT FINITE TEMPERATURES

It is shown that the difficulties met in the perturbation calculation of quantum field processes at finite temperatures are all due to improperness in the formulationaqd to certain ad hoc manipulations in previous versions of the theory. They disappear in the CTPGF (Closed Time Path Green's Function) formulation initiated by Schwinger, implying that the latter formulation brings about a more satisfactory theory.     

PATH INTEGRAL CALCULATION OF QUANTUM TUNNELING FOR CUBIC POTENTIAL AT FINITE TEMPERATURE

The periodic instanton method is used to study the decay rates of metastable ground state and excited states of the cubic potential. The imaginary part of the energy is calculated through the standard procedure in the path-integral scheme. A formula of the decay rate valid for the entire region of energy is obtained. This formula provides a linkage between classical thermal activation at high temperatures and purely quantum tunneling at zero temperature. It is shown that in the low energy limit this more general result reduces exactly to the vacuum result. The temperature dependence of the decay rate agrees with earlier works in the literature.     

极性晶体内表面电子的量子像势及其极化子的有效势

本文从与真空接触的存在二支声子的半无限极性晶体表面附近极化子的哈密顿算符入手，应用二支模型理论，分别对GaAs和ZnO两种材料计算了内表面电子的量子像势及其极化子的有效势。计算结果表明：当Z很小时，经典像势和半经典有效势分别与量子像势和量子有效势相差较大；当Z很大时，经典像势和半经典有效势分别是量子像势和量子有效势的一个很好的近似。     

硅、锗中氧的低温红外吸收

在6—300K下,利用红外傅里叶光谱仪研究了400—4000cm^-1间的硅、锗中氧的红外吸收。采用高分辨条件时,分辨率可达0.5cm^-1。研究了在低温下利用硅的1106cm^-1吸收峰和锗的855cm^-1吸收峰探测硅和锗氧含量的探测限和误差。若样品厚度为2cm,估计在20K下,硅中氧含量探测限～9.6×10¹⁴氧原子·cm^-3,锗中氧含量探测限～3.0×10¹⁴氧原子·cm^-3。同时,对不同生长条件下直拉锗单晶的氧含量进行了研究,并与用锂沉淀法所求得的锗中氧含量加以比较。对不同氧含量的硅样品的1106cm^-1吸收峰在6—300K的变化进行了观察和讨论。 关键词：     

有限温度场论单粒子不可约图形的零动量行为

本文利用闭路Green函数理论讨论了有限温度场论单粒子不可约(1PI)图形的零动量行为,并且证明在体现Kubo-Martin-Schwinser条件的“│P₀│方案”下,这种图形的推迟函数的零动量极限是完全确定的。 关键词：     

INFLUENCE OF C+-IMPLANTATION DOSE ON BLUE EMISSION AND MICROSTRUCTURES OF Si-BASED POROUS β-SIC

Crystal Si were implanted with different doses of C⁺ from 10¹¹ to 10¹⁷ cm^-2 at an energy of 50 keV. β-SiC precipitates were formed by thermal annealing at 1050 ℃ for 1 h and porous structures were prepared by electrochemical anodization. Under the excitation of ultraviolet, the samples, with C⁺ dose ≥10¹⁵ cm^-2 have intense blue emission which is stronger than the photoluminescence (PL) intensity of reference porous silicon (PS), and increases as C⁺ dose increases; the samples with C⁺ dose ≤10¹⁴ cm^-2 show similar PL spectra to those of PS. The blue peak intensity in PL spectra is correlated with the TO phonon absorption strength of β-SiC in infrared absorption spectra. The transmission electron microscopy study shows that the blue peak is also correlated with the microstructures. Because porous β-SiC is nanometer in size, it is suggested that the quantum confinement effect be responsible for the blue light emission.     

缔合流体在高温高压下的自扩散系数研究

在统计力学理论基础上,本文提出了一个考虑氢键对自扩散系数影响的方程．这个方程为非氢键贡献部分与氢键贡献部分之积,其中自扩散系数的非氢键部分由Ｌｅｎｎａｒｄ－Ｊｏｎｅｓ链模型求得,而一个分子中的平均氢键数随温度和密度的变化关系使用统计缔合流体理论得到。链节之间的相互作用能量参数由粘度的关联式获得,其它四个参数则由扩散系数的实验数据获得。对７个典型的缔合流体在相当宽的温度压力范围内计算的平均相对百分误差为５．９８％。