We study the crack propagation in layered solids and find that when there exists an easy-fractured layer, the fractal surface becomes more rough, which is characterized by larger fractal dimension.

The quantum fluctuations of the pump and signal waves are derived for degenerate parametric down conversion from a pump field initially in the squeezed state. It is found that, to the quadratic term, while the degree of squeezing of the pump wave decays gradually, that of the generated signal beam increases up to a maximum then decays.

Co-implantation of phosphorus was used to enhance the activation of the implanted magnesium in GaAs. Improved activations were observed in dually implanted samples by either furnace annealing or rapid thermal annealing. For dose of 5x10¹⁴ cm^-2 Mg⁺, an activation of 74% with a sheet resistance 216Ω/⊗ was obtained for dual implant compared to the activation of 33% and sheet resistance of 367Ω/⊗ for single implant after rapid thermal annealing. The results suggest that the high carrier concentration can be obtained by this technique.

Considering the space charge effect on gas multiplication a semi- empirical formula of the gas gain in limited proportional region is proposed. Two parameters of gas multiplication, the, threshold of limited proportional region Vs and the coefficient of space charge suppression B, are introduced. Analyzed the experimental data the values of these parameters under different experimental conditions are obtained.

Heating finite betas (relative to low beta) tokamak plasmas by Alfven waves is studied by means of a linearized kinetic model which takes into account ion sound and transit time magnetic pumping as well as the effect considered by preceding authors. In cylindrical geometry, a set of three second-order differential equations in r for the perturbed fields E_r, E_⊥, and E_|| is solved numerically. The results lead to a significant conclusion that Alfven wave heating may be an advanced way of heating plasmas in future tokamaks.

Microturbulence density fluctuations with drift-wave characteristics in KT-5B tokamak were investigated. The density fluctuation power spectrum S(k_⊥) can be fitted into S(k_⊥) ∝ k_⊥^-α, in which α is in inverse proportion to the toroidal magnetic field B_T. Both averaged frequency and width (FWHM) of the frequency spectrum are increasing functions of B_T. The phase velocity from the statistical dispersion is larger for k_⊥ < 20cm^-1 than that for k_⊥≥ 20cm^-1.

Shear Alfven waves have been successfully excited in KT-5B small tokamak by means of the one turn longitudinal loop antenna located in the shadow area. The measured antenna loadings show their rich structure, and the loadings are also found to be sensitive to the plasma current. Preliminary evidence of surface electrostatic wave was observed.

200keV Xe ions were implanted in potassium titanyl phosphate (KTP) at deferent angles: 0°, 45° and 60°. The lateral spread of Xe ions in KTP was studied by Rutherford backscattering of 2.1 MeV He ions. The result is compared with the theoretical prediction. The lateral spread is found in good agreement with calculated value within 17 %.

Optical microscopy, optical transmission spectra, sweep electron microscope, electron microprobe analysis etc. were used to study the appearance and machanism of formation of the defects caused by impurities which seriously affect the optical transparency of doped bismuth germanate. The methods of improving the optical transparency were also discussed.

The martensitic phase transformation which produces shape memory is connected with a hysteresis. Some of the applications of shape memory alloys require small hysteresis loops, other require large ones. It is therefore important to be able to control the size of the hysteresis. For that purpose three different methods were introduced in the present paper. Mechanical vibration narrowed the hysteresis loops in both NiTi and CuZnAl alloys up to 17%, while the width of the hysteresis loops in a NiTi alloy decreased 3~4 times by addition of the third element Cu. With help of a special heat treatment a nearly hysteresis-free phase transformation occured in a Ti-51Ni(at.%) alloy. The size of the hysteresis is determined by the interfacial energies of the phase boundaries and these will be big, if the E-modulus and the lattice distortion are big.

Cadmium telluride thin films were prepared by vacuum evaporation of CdTe powder in an attempt to fabricate all thin film solar cells of the type CdTe/CdS. Characterization of CdTe has shown it to have a band gap of 1.522eV and a resistivity of 22Ω-cm. As prepared, solar cells exhibited low values of output parameters. Given quantity of copper was then deposited on top of the CdTe/CdS solar cells and the whole system was annealed at 350°C. This copper doping changed the output parameters favorably with a maximum efficiency of 1.9%.

Besides the structure and oxygen content, the resistance-temperature relationship, Hall carrier concentration (nH) and midpoint temperature of superconducting transition (T_c) were measured for more than six 123-phase systems with elemental substitution. No correlation is found between the oxygen content and T_c, nor is between the orthorhombic structure and T_c. Instead, an unmonotonic relationship is jound between nH and T_c. The optimum nH for the highest T_c is about 3.8 x10²¹cm^-3. All this draws a conclusion that nH is a parameter to describe the high T_c superconductivity.

In this paper, a one-dimensional short-ranged spin-glass model in a random magnetic field is studied. Noticing convexity of the partition function, we use Jensen's inequality to obtain a lower bound to the averaged free energy density and the slope inequality for an upper bound. These bounds are derived under very general conditions and they can be used as tests for various approximate methods such as the replica method.

A series of R₂ Fe₁₇C_x compounds (R=Y, Pr, Nd, Sm, Gd, Dy, and Er; x=0, 0.5 and 1.0) were synthesized. X-ray diffraction analyses showed that the crystal structure is rhombohedral Th₂Zn₁₇ type for R=Pr, Nd, Sm, and Gd. For R=Y, Dy and Er, a structure transformation from hexagonal Th₂Ni₁₇ type (x=0.5) to rhombohedral Th₂Zn₁₇ type (x=1.0) was observed. The introduction of C into R₂Fe₁₇ leads to an expansion of the lattice. It strongly enhances Curie temperature. C atoms occupy interstitially the nearest neighbour sites to the R atoms in the lattice. The anisotropy of R sublattice was strengthened. A uniaxial anisotropy was observed in Sm₂Fe₁₇C_0.5 at room temperature.

A prospective new organic material: 3-methoxy-4-hydroxy-benzaldehyde (MHBA) with powder second harmonic generation efficiency 30 times as large as that of urea and the cutoff wavelength of 370nm is reported. MHBA belongs to monoclinic system space group P2₁, and the unit cell parameters are: a=14.057Å, b=7.875Å , c=15.037Å and β=115.45°, the general physicalchemical properties are also presented.