The dynamical equation of diluted Hopfield neural networks with self-couplings is calculated by analytical approach. The presented results show that the self-coupling strongly influences the dynamical behavior of the network, making the critical loading value α_c smaller remarkably and the size of basin of attraction decrease.

The Compton profiles of Polycrystalline graphite and nanometeric graphite produced by mill grinding were measured and the Compton profile of polycrystalline graphite was calculated. The theoretical and the experimental Compton profiles of polycrystalline graphite, the experimental Compton profiles of nanometeric graphite were compared.

In the recent charts of the nuclides an accepted half-life of ⁷⁹Se is only an upper limit, < 6.5 x 10⁴ a. In this letter, A new half-life of ⁷⁹Se has been measured to be (1.13 ± 0.17) x 10⁶a. The number of ⁷⁹Se atoms was determined from measured ⁷⁹Se /Se ratios with the accelerator mass spectrometry technique and the decay rate of ⁷⁹Se was determined by counting the emitted β rays with a liquid scintillation spectrometer.

The high-spin states in ¹⁹⁷Bi have been studied with the ¹⁸⁷Re(¹⁶O,6n) reaction at ¹⁶O energies from 85 to 105MeV. In-beam measurements of γ-ray excitation functions, γ -γ -t coincidences and γ-ray angular distributions were carried out with six BGO(AC)HPGe detectors and one intrinsic Ge planar detector. Eleven new transitions and three new isomers were observed, and a level scheme for ¹⁹⁷Bi was established. Some differences between the present work and the previous results were found.

An exact two-soliton solution of cubic Schrödinger equation is derived by using the inverse scattering method, where the transmission coefficient has one pole of second order instead of two simple poles. This solution describes such a process that two infinitely separated solitons approach and then pass through each other and keep straight on infinitely.

By using the transfer matrix method, we present a general model for evaluating the ultrasonic scattering cross-section from a cylindrical multilayered medium. A numerical computation is given for an SCS-6/Ti fiber. This model can be conveniently used to estimate the ultrasonic scattering from a cylinder consisting of any number of layers.

The laser-generated transient Lamb wave in thin isotropic plates is studied theoretically by employing the method of eigenfunction expansion. The thermoelastic displacement field is expressed by symmetric and antisymmetric Lamb wave modes, so that it is convenient to investigate the transient excitation of the lowest and higher order Lamb wave modes. The characteristics of transient Lamb waves in thin materials
with different thicknesses are discussed in details.

A nonlinear fluid description for the parameter processes has been derived. The linear instability analyses about three wave mixing process ω₀ →ω_s1 + ω_s2 and four wave scattering process ω₀→ω_s + ω_P1 + ω_P2 have been made. Correspondent backward or side scattering light waves emitted from mentioned processes may provide valuable information for the diagnostic of plasma parameters.

A series of coupling equations for the relativistic coherent harmonic generation is derived taking account of the coupling effect among the harmonic contents and plasmas wave. Using these equations, the growth and saturation of amplitude of the third harmonic wave is investigated. Results show that the coupling effect induces the saturation of harmonics, which is identical with ones of the Lagrangian description.

We have studied the microstructure and photoluminescent properties of porous Si. High resolution observations revealed that the microstructure of porous Si consists with nano-crystallites Si embedded in the surrounding amorphous matrix. The structure of nano-crystallites of porous Si is not consistent with the usual diamond structure of bulk Si. The photoluminescence from porous Si is due to the quantum confinement of carriers in this structure.

In this paper, a new model of potential energy functions for atomic solids is given and applied to silicon and germanium crystals. Obtained potentials of Si and Ge crystals accurately reproduce experimental elastic constants and phonon dispersion curves.

We report a novel technique for growing high-quality GaAs on Si substrate. The process involves deposition of a thin amorphous Si film prior to the conventional two-step growth. The GaAs layers grown on Si by this technique using metalorganic chemical vapor deposition exhibit a better surface morphology and higher crystallinity as compared to the samples grown by conventional two-step method. The full width at half maximum (FWHM) of the x-ray (004) rocking curve for 2.2 μm thick GaAs/Si epilayer grown by using this new method is 160arcsec. The FWHM of the photo-Luminescence spectrum main peak for this sample is 2.1 meV. These are among the best results reported so far. In addition, the mechanism of this new growth method was studied using high-resolution transmission electron microscopy.

In this letter, we study the effects of the interlayer hopping and pairing of the layered high-T_c superconductors within the framework of BCS-van Hove singularity model. The obtained results are in qualitative agreement with the experiments.

We have presented the electronic free energy with respect to the magnetization and the model of the electronic density of states. The expression of the giant magnetoresistance has been obtained by considering the spin splitting of the electronic energy band. Our approach explained the temperature effect on the giant magnetoresistance in magnetic multilayers.

We report a study of the resonant Raman scattering (RRS) by optical phonons that is induced by excitons bound to isoelectronic nitrogen impurities in GaAs_1-xP_x:N alloys. Under resonant excitation into N_x band, strong Raman lines involving allowed LO and “forbidden” TO for backscattering configuration from (100) surface are observed. This is interpreted as the breakdown of normal selection rule in the RRS process. By following the temperature dependence of the N_x luminescence and its phonon sidebands, we also separate RRS from sharp line due to luminescence.

The internal vibrations of the ammonium ion in (ND₄)₂TeCl₆ have been studied by Raman scattering in the temperature range 4.2-300K. Splittings of A₁-, E-, and T₂-modes have been observed at T_c2 = 48 K and T_c3 = 28 K. These splittings were well interpreted by group theoretical correlation method. The reason for the transitions at T_c2 and T_c3 may be the decrease of the force constant in the deuterated ammoniumion.

Si aerogel, the porous silicon with ultra high porosity, has been prepared by the technique of anodization followed by supercritical drying. Its photoluminescence, photoluminescence excitation and morphological features exhibit novel characteristics from those of the conventionally anodized porous silicon. We observed the differences between the Si aerogels made from <100> and <111> crystalline Si.

Using photoemission spectroscopy, we have studied the adsorption of Sm on C₆₀ film. At the first stage of Sm adsorption, the C₆₀ valence band shifts to the high binding energy side. The maximum shift is about 0.4eV. In the meantime, there appears a new structure at the upper side of the highest occupied molecule orbit (HOMO) band, which comes from the hybrid of the Sm 4f ⁵ state and C₆₀ HOMO band. As Sm coverage increases the Sm electron is in a kind of Sm²⁺ state due to the forming of Sm cluster on the surface.

The carbon-nitride thin films were deposited on the (100) oriented single-crystal KCl wafers at ambient temperatures by using rf-plasma sputtering. The IR spectrum showed that the films contained carbon-nitride bonds. The transmission electron microscopy (TEM) and x.-ray diffraction (XRD) measurements indicated the existence of predicted polycrystalline β-C₃N₄ films on the KCl(I00) wafers. And the TEM and XRD measured lattice spacings well match the calculated data.

An improved sputtering method, which is named “in situ oxidizing sputtering”, was used to prepare periodic Ni/NiO multilayers. Samples studied in this letter contains 20 pairs of Ni/NiO with period about 100Å. In Raman scattering, the low frequency phonon modes are interpreted as LA phonon folding effect, which is usually measured in superlattices with a strict periodic structure. The ferromagnetic resonance spectra were also recorded at room temperature with microwave frequency 9.777GHz. The analysis of spin wave resonance indicates that Ni sublayers are coupled with each other, which is the mechanism that surely relates to the amorphous-like NiO spacers.

The velocity non-uniformity of the particle movement in the living cells is investigated. Introducing the concept of molecular fluctuation in the living cells, the phenomenon of the velocity non-uniformity is explained. A quantitative relation between molecular fluctuation and velocity non-uniformity of the particle movement is derived.