The first observation of collisional narrowing by time-resolved degenerate four-wave mixing has been reported. The velocity-changing collision cross section of Na in Ar De obtained is 5.6 x 10^-15cm².

X-ray diffraction, SEM and XPS were used to detect the structure of sputtered a-Si_1-xSn_x:H alloys. It is verified that the types of Sn site in the alloys depend on substrate temperature T_s. Most of the Sn atoms are substituted for Si at T_s 220°C, whereas a larger fraction of β-Sn clusters are formed at T_s 220°C.

We present an SUSY GUT model, in which the strong CP violation can be eliminated via the invisible axion mechanism. We show that any b_1,1 = 0 model cannot use the entropy production mechanism, however, A2 ,A3 , A4 , A5, B2, B4,B5 and C2 in b_1,1 1 case can do. As an example, we present an A4 model in which axion are diluted efficiently by the entropy production and the fast proton decay is forbidden without requirement of discrete symmetry.

A simple, direct method of measuring vapor density by Faraday rotation technique, which in principle has no upper limit in vapor temperature, is reported. An experimental illustration with Rb vapor is also presented.

The focusing and scanning of the acoustic beam in solid have been carried out by using the Fresnel transducer array of ZnO thin film with a bandwidth of 200MHz. Some useful properties were observed experimentally by the acousto-optic method and analysed phenomenologically.

By introducing mass density waves, we have determined the positions and intensities of a quartet of spots around the (±1/2, ±1/2) positions on a clean Mo(100) surface at low temperature. lt is shown that the Mo (100)-C(2x2)* incomensurate surface structure is a stable one and can be described in terms of a C(2x2) superlattice modulated by square-like-domains. The domain size and the direction of the domain structure relative to Mo(100) lattice are also discussed.

Using a high pulsed magnetic field system up to 200kOe, we have investigated the magnetic properties of (Nd_1-xTb_x)_16.7Fe_75.5B_7.8 (x = 0,0.05,0.1,0.2,0.4) at a temperature range 77-450K. The results show that the spin reorientation temperature T_s decreases with the increase of x.

Powder neutron diffraction measurements have been carried out on the Al-Mn quasicrystal at room temperature. Nine diffraction peaks of the quasicrystal phase were observed, and indexed on the basis of six independent reciprocal vectors pointing to the vertices of an icosahedron.

The properties of LSW propagation under Periodic metal grating have been investigated by using a new method of field analysis that leads to a satisfactory solution fitting the electrical boundary conditions. The detailed dispersion relation and the curves of attenuation constant for LSW on 49°Y-X LiNbO₃ are presented. The discussion and comparison between the theory and experiment for the first stopband are also made.

We studied the pressure dependence of N and NN_i traps in GaP based on EPM band structure. In calculation of Green's function, we used an approximate method combining with the special points method and the effective mass description of the band valleys. The results are in good agreement with the experiments only when proper changes of the effective masses under pressure are taken into account.

The problem in the criterion often used to judge whether the Feynman scaling in fragmentation region is violated or not is discussed. Subtracting the contamination of central region particles from the large pseudo-rapidity region by Monte-Carlo simulation, the reasonable pseudo-rapidity distribution in fragmentation region is obtained and a possible signal on the scaling violation in fragmentation region is seen.

We calculated the q-th order information dimension D_q and the spectrum f ( α ) of singularities in the measure for t4e limiting sets of period-n-tupling sequences in the case of the logistic map.