In this paper we present the results of our preliminary study on the improvements of torsion pendulum in order to make it suitable for the viscosity measurement of melt at high temperature. The amplitude features of conventional torsion pendulum and our method have been compared at room temperature and at high temperature, respectively. The relationship between the damping factor and the kinematical viscosity is derived and discussed. The viscous properties of molten KNbO₃ and molten Li₂B₈O₁₃ at high temperatures in air are measured with this method.

In this letter, we try to analyze the effects on final pseudoscalar meson η,η' production rates of γ decay produced by pseudoscalar mixing angle, “mass effect” and L = 1 mesons production. If L = 1 mesons production is taken into account, the calculated production rates of η' and η and the ratio between them agree well with ARGUS data at certain mixing angles, otherwise, the data cannot be explained completely. Hence we come to the conclusion that L = 1 mesons production cannot be neglected.

By 22MeV proton inelastic scattering at the forward angle of 10°, the orbital character of new low-lying M1 excitation states in ¹⁶⁰Gd has been verified. At the same time, several new energy levels of ¹⁶⁰Gd are observed, and values of spin, parity and deformation length for two new energy levels with excitation energies of 2.558 and 2.607 MeV are given via collective distorted wave Born approximation calculations.

For the reaction systems with α < α_BG, the fissioning nucleus goes through saddle-point to fission with some memories of the entrance-channel plane. In these cases, by taking the relaxation process of K degree of freedom into account, the varience of K distribution, σ²_k is obtained. It is shown that σ²_k exponentially depends on the square of the angular momentum, J² for the reaction systems with α < α_BG.Therefore, we have put forward a new version of preequilibrium fission model, and shown the experimental evidence for this new fission mechanism.

Generalized Boltzmann approximation of the phase-space distribution function of quarks in the quark phase and of pions in the hadron phase, adopted by previous authors, to a complete expression, the dilepton production in Bjorken's (1+1) dimensional scaling expansion system is studied. We find that the dilepton production is heightened, and the shape of the characteristic dilepton dietribution for the quark matter formation in ultrarelativistic nucleus-nucleus collisions is significantly changed.

Excitation functions for projectile-like fragments from ¹⁹F+⁵¹V reaction have been measured at 102.25 to 109.50MeV in 250keV steps. A TOF+(Δ E - E) telescope at θ_L = 21.7° is used to identify atomic number Z and mass number A of ejectiles simultaneously. Fluctuations of the dissipative cross section for a series of isotopes are observed. Their coherence energy widths are extracted by generalized statistical fluctuation analysis and the dependence on mass number and on N/Z values are observed for the first time.

A dynamical scheme is employed to simulate the self-trapping of the exciton in C₆₀. During the self-trapping process, due to the bond distortion, two gap states A_1u and A_2u are separated from the highest occupied molecular orbital and the lowest unoccupied molecular orbital respectively. From the evolutions of the bond distortion and these two levels the relaxation time of the self-trapping exciton is about 90 fs. It is noticed that the relaxation of the exciton is much quicker than that of the charge transfer in C₆₀.

Based on the interference between one-photon and two-photon processes, we report polarization beats in a cascade three-level system (PBCTS). We performed PBCTS experiments in Na vapor, which showed a modulation of the four-wave mixing signal intensity with period 55fs, corresponding to the beating between the resonant frequencies of the transitions from 3S_1/2 to 3P_3/2 and from 3P_3/2 to 4D_3/2,5/2.

In this letter, we present the observation of phase conjugation at 9.27μm in a GaAs/AlGaAs multiple step quantum well structure. The response is caused by the nearly resonant intersubband transition. The magnitude of x⁽³⁾ determined by this phase conjugation method is about 8 x 10^-5 esu and the phase conjugate reflectivity η is about 6 x 10^-3 uncorrected for Fresnel reflections.

The chaotic behaviors of the time series of the breather (soliton) amplitude have been observed experimentally in the shallow water in the trough subjected to parametric exciting vertically. The results predict that the water solitary waves should be described by some chaotic equations in the higher order approximations as well as by the nonlinear Schördinger equation in the first order.

The biexciton in conjugated polymers is studied in the Su-Schrieffer-Heeger model appended by a long-range Coulomb interaction. The wave function of the biexciton is constructed in the Heitler-London approach and, for the first time, the binding energy and radius of the biexciton in conjugated polymers is calculated.

Intersubband transitions from L₁ to L₂ subbands in AISb/GaSb superlattices in the 8-18 μm wavelength range are observed by employing normal- and oblique-incident Fourier transform infrared (FTIR) spectroscopic techniques. Using AlSb rather than GaSb as the buffer layer, interference oscillations in normal-incident FTlR spectra are significantly reduced, which facilitates one to distinguish intersubband transition features. In the oblique-incident mode where a 45° thallium hexahedron is used for internal reflection, interference oscillations are eliminated, making it possible to observe weak intersubband transitions that cannot be distinguished in normal-incident absorption spectra.

Terahertz (THz) far infrared radiation with a subpicosecond pulse duration is generated from GaAs(100) surface illuminated by femtosecond laser pulses. By illuminating the sample with another pump pulse, we observe an enhancement of THz emission. A mechanism of photocarriers trapping by impurities and defects in the depletion layer is proposed.

Fullerenes (C₆₀/C₇₀) were encased in silica aerogel by sol-gel process followed by supercriticd drying technique. Visible light emission was observed from the composite under Ar⁺ laser (488nm) excitation at room temperature. The luminescent intensity was found to decrease whilst being red shift with the increase of the fullerene content in the composite (from 0.05 up to 2.5mol%). This can be interpreted with quantum confinement effect of fullerenes confined in networks of the nanoporous silica aerogel.

We report a detailed analysis of optical properties of single submonolayer InAs structures grown on GaAs (001) matrix. It is shown that the formation of InAs dots with 1 monolayer (ML) height leads to localization of exciton under certain submonolayer InAs coverage, which play a key role in the highly improved luminescence efficiency of the submonolayer InAs/GaAs structures.

When the relativistic electrons produced by in situ acceleration propagate through the plasma of jets, they will drive the fluid components to rotate around the cylindinal axis. The shear of rotation veiocity will amplify the magnetic fields through kinematic screw dynamo mechanism.