[en] In the authors' theoretical approach, the relaxation mechanism of the quasi-positronium (qPs) in alkali halides has been studied. It can be shown that the electronic cloud polarization in the medium results in the screening effect on the Coulomb potential of electron-positron pairs, so as to lead to the relaxation phenomena. Because the mean distance between the electron and positron in qPs is of the order of the lattice constant in alkali halide crystal, the Toyozawa's Hamiltonian in which only long range interaction between a charged particle and the medium is considered, could not be fitted in with the case of the qPs. So the authors try to make 'the short range force correction' to the interactive Hamiltonian by using phemomenological method. Then the total Hamiltonian can be solved into the effective Hamiltonian of the qPs by means of the method which had been used to treat the exciton by Ku Shih-wei. It is shown that the result of variational treatment of the effective Hamiltonian is in good agreement with the experimental data, so the relaxation mechanicm of qPs can be interpreted quantitatively

[en] The (5p_1/2nd)₃ (n equal to 11 to 24) auto-ionizing levels of Sr have been measured by the laser melti-step excitation technique. Their effective quantum numbers have been determined. The interaction with the (5p_3/2nd)₃ series has been discussed

[en] By injecting a high power microwave into the CT-6B tokamak plasma, the experiments on the pre-ionization of the tokamak discharge at the fundamental and the second harmonic resonance of the electron cyclotron wave were performed. The experiments verified that the microwave pre-ionization is very effective for the reduction of the loop voltage and the magnetic flux in the early stage and suppression of the production of runaway electrons in the quasisteady stage. The effect of the microwave pre-ionization with the fundamental cyclotron resonance is better than that with the second one

[en] In this article the construction of measurement system on HT-6B Tokamak which is highly sensitive to soft X-ray fluctuation is described and the primary results presented. When the average electron temperature Tsub(e)-bar is less than 100 eV, the wave shapes of typical soft X-ray fluctuations, the disruptive instabilities, the MHD disturbances, and some other interesting phenomena have been observed

[en] The linear behavior of the double tearing mode driven by anomalous electron viscosity effects associated with magnetic braiding is investigated within the framework of MHD. A two-space-scale analysis is performed and the result is used to obtain an approximate dispersion relation for the mode. If the separation of the rational surfaces at x=+-xsub(s) is sufficiently small, xsub(s)/a<<(ksub(y)a)sup(-11/15)Rsup(-1/15), the growth rate is predicted to scale as Rsup(-1/5). With increasing separation the mode makes a transition to Rsup(-1/3) scaling, where R = tausub(ν)/tausub(H). The Rsup(-1/5) scaling is shown to be correlated with violation of the constant-psi approximation

[en] In the slab model the so-called universal modes are absolutely stable. How about the cylindrical plasma. The main difference is that instead of the out-going boundary condition in the slab mode, in the cylindrical plasma there is not any wave energy out-going at r = 0 and r = α. This may change the stabilities of the modes effectively. Assuming exponential plasma density and current profiles, the integral eigen-equation of drift wave has been derived. In the case of slow radial variation, it can be converted into a second order differential equation. The equation has been solved numerically. The results show that the unstable modes do exist. The comparison between the two models (cylindrical one and slab one) has been made

[en] This article investigates the influence of collective effects of plasma on bremsstrahlung. According to the theoretical results we obtained, the influences on the inverse bremsstrahlung absorption of laser light and the spectrum and total energy of spontaneous bremsstrahlung are studied numerically

[en] Inelastic neutron scattering spectra from C-15 phase superconducting alloys V₂Hf, V₂Ta, V₂Hfsub(0.8)Tasub(0.2), V₂Zrsub(0.5)Hfsub(0.5) and V₂Zrsub(0.5)Hfsub(0.33)Tasub(0.17) were measured by the neutron time-of-flight method, and their relative phonon densities of states were evaluated. The present results show that the phonon frequencies soften with the increase of the superconducting transition temperature Tc and harden with the decrease of the Tc, which is in agreement with our previous results of 'The effect of Nb on phonons of superconductors C-15 V₂Zr and V₂(Zrsub(0.5)Hfsub(0.5))'. This means that for these superconductors the elastic softening plays a role in enhancing Tc to some extent. It seems that between V₂Zr or V₂Hf and V₂(Zrsub(0.5)Hfsub(0.5)) there exists essential difference, which makes Tc increasing and the phonon frequencies softening for the formers while Tc decreasing and the phonon frequencies slightly hardening for the later after adding small amounts of Nb or Ta. It can be considered as the result of hybridization of conduction bands, which is studied by means of the LMTO (linear combination of muffin-tin orbitals) method

[en] We analyse the jet-charge-cross section of following three reactions: p + p → γ + Jet + X, γ + p → 2Jets + X, γ + p → h + Jet + X, and present the methods respectively for testing gluon distribution function in proton, extracting the information of gluon jets and determining the fragmentation function of gluon

[en] Soft X-ray diagnosis is an important method in the research of tokamak plasma instability. In this paper, we give the result of soft X-ray measurement in CT-6B tokamak by using Au(Si) surface barrier detector array, and present the spatial distributions of soft X-ray emission for various plasma instability in our device