In this paper a suggestion of summation over steepest-descent contours in path integral approach to quantum cosmology is given, with which the wave function describing the evolution of the universe can be uniquely specified.

The wormhole solution of a finite temperature scalar ø⁴ field coupled to gravity is given. It is shown that Hubble constant and the size of the wormhole neck all increase with temperature. Temperature dependences for other physical properties of wormhole are also discussed.

The ¹⁴N(d, α )¹²C nuclear reaction has been used to measure the nitrogen content in iron meteorites. The analysis was made with 2.0MeV²H⁺ beam from Brookhaven 3.5MV research electrostatic accelerator. The detection limits of about 1 ppm were achieved.

It is possible to deflect a group of atoms with a certain velocity from an effusive atomic beam if we use a properly detuned laser beam with a small angle off orthogonal to the atomic beam. Theoretical and initial experimental results of this simple method for velocity selection are given.

The gauge problem of Keldysh-Faisal-Reiss theories is discussed. It is found that the E-gauge used by Keldysh is more reasonable than the A-gauge used by Reiss. The Keldysh theory is then developed further. Its differential ionization rate gives more hot electrons than Reiss's and therefore better agrees the experimental result. The another remarkable point is that the differential ionization rate as a function of energy is rapidly oscillatory.

We have introduced the electron cyclotron maser instability to tokamak plasma and proved that the maser instability can take place in runaway discharges. This instability amplifies the electron cyclotron emission in a rather lower frequency compared to gyrofrequency.

Using spatially averaged global model, we succeed in obtaining some plasma parameters for a low pressure inductively coupled plasma source of our laboratory. As far as the global balance is concerned, the models can give reasonable results of the parameters, such as the global electron temperature and the ion impacting energy, etc. It is found that the ion flow is hardly affected by the neutral gas pressure. Finally, the magnetic effects are calculated by means of the method. The magnetic field can play an important role to increase plasma density and ion current.

Depth profiles of fluorine in ¹⁹F⁺ implanted Ni_0.8Fe_0.2a alloy have been accurately measured by using ¹⁹F(p,α γ)¹⁶O resonance nuclear reaction at E_R = 872.lkeV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The range parameters, R_p and ΔR_p, were thereby obtained and compared with those simulated wit TRIM90 code. It shows that the experimental R_p values agree with the Monte Carlo simulation values very well, while the experimental Δ R_p values are systematically larger than the calculation values.

Influence of the position of the Fermi level on the infrared active defect, so-called higher order bands (HOB), has been investigated in neutron irradiated silicon by using infrared absorption and Hall-effect measurements at low temperatures. The optical excitation and the introduction of thermal donors (TD) effectively alter the position of the Fermi level. Similar optically active behaviors between the HOB and TD⁺ have been observed. It is suggested strongly that the mechanism of the Fermi level influencing on the HOB is the same as that of the TD⁺.

An improved XY model is adopted for the vortices in the superconductors. In the case of high density, the fugacity should be modified by the higher harmonics. By use of the variational effective potential, we analyze the discontinuous phase transition for the dense vortices below the Kosterlitz-Thouless transition temperature.

The specific heats and temperature dependence of the x-ray powder diffractions for the D-valine and the L-valine single crystal samples have been studied. It is found that there is a specific heat jump at 272.0K for the D-dine samples but no jump at the same temperature for the L-dine sample. The lambda like transition means that the co-operative effect is involved in this transition. There is no crystal structure transition in the temperature range of 123-293K for the D-dine sample. The transition of the D-valine sample might be the possible D-L transition which is proposed by Abdus Salam.

Reactive deposition-solid phase epitaxy has been developed for the epitaxial growth of thick β-FeSi₂film. Compared with the solid phase epitaxy, the crystal quality was improved. The orientation relationship mainly depends on the depositing condition. Observation by transmission electron microscope revealed the polycrystalline nature and the mean crystallite size was about 200nm.

A new type of light-emitting device with Al-MgF₂-Au(Cu) junction and the role of residual O₂ in fabrication of Al-MgF₂-Au(Cu) thin film devices were reported in our other papers. In this paper, we made a further careful investigation about its current-voltage (I - V), current-temperature (I - T) characteristics and the observed light emission spectra in detail. We find the presence of Schottky high field emission in an evaporated sandwich structure of Al-MgF₂-Au(Cu) junctions, and argue that the radiation process is mainly due to Schottky hot electrons, which excite surface plasmon-polariton (SPP), then SPP couples to external radiation through surface roughness.

The mechanical dissipation of (Bi_0.9Pb_0.1)₂ Sr₂ Ca₂Cu₃O_10+y and YBa₂Cu₃O_7-x ceramics were measured as a function of the angle θ between the orientation of the transverse magnetic field and the vibrating direction at fixed temperature and magnetic field with the vibrating reed technique. A relation between Q^-1 (or f) and The angle θ, i. e. Δ Q^-1 (or Δ f) ~ (H_a cosθ)^1.5 was found and this indicated that only the magnetic field component parallel to the vibrating direction H_a cosθ gives rise to the enhancement of internal friction and resonant frequency in ceramic sample. The anisotropic deformation of flux-line-lattice is used to explain the observed results.

The unpaired spin S = 1/2 states which occur at the ends of an S = 1 Heisenberg-like antiferromagnetic chain, have been observed recently in low-temperature electron spin-resonance measurements of Ni(C₂H₈N₂)₂ NO₂ ClO₄containing selected impurities. We present here a further study on this topic by far infrared transmission spectra under the magnetic field. The splitting of S = 1/2 modes was clearly observed and explained by the interaction of S = 1/2 modes at two nearby chains, which can be separated by vacancy-like defect.

The photoluminescence (PL) spectra of C₆₀ single crystals grown under double temperature gradient (DTG) and single temperature gradient (STG) techniques were investigated at room temperature. The results show that the PL emission intensity increases first and then decreases with increasing illuminated power density for the C₆₀single crystals grown by both DTG and STG techniques. Furthermore, one main peak with a shoulder peak can be clearly distinguished at low illumination, while only one main peak without the shoulder peak can be seen at high illumination. The main peak undergoes a continuous blue shift and broadening with the increase of illuminated power density. The difference of PL emission energy at the same illumination density of DTG and STG samples may correlated with the degree of both the orientational disorder of C₆₀ molecule and lattice perfectness. The Laue diffraction patterns show that the DTG sample has stronger strains and poorer crystalline quality than the STG sample.