A method for transmitting multiple digital information signals by a single transmitted chaotic signal is presented. The information signals are encoded by modifying some tunable parameters of a chaotic system and decoded at the receiver by following the parameter modulation in the transmitter via synchronization. The Lorenz system is used to demonstrate the validity, robastness and security of the method.

The replica trick used in the renormalization group (RG) for the disordered spin systems is discussed. The recursion relations of RG are derived in a more general situation in which the coupling constants can have arbitrary symmetry to the replica indices. It is shown that the random fixed point found by Luther, Grinstein and Lubensky is unstable. This instability implies that the replica symmetry should be broken in the RG for the disordered systems.

The ratio of isotope yields integrated over a part of their energy spectrum is proposed to extract nuclear temperature of the excited emitter nucleus formed in heavy ion reactions. The nuclear temperature extracted from the isotope ratio is consistent with that extracted from the relative populations of the particle unstable states.

The computation of near zone fields is very important in many practical applications. Accurate analyses of the on-axis fields of a circular disk by transient and harmonic excitation show that there is an energy uprising zone on the axis rather than a non-decaying one, provided that the disk is excited by a rectangular pulse, the duration of which is less than the ratio of the radius to the light velocity. Similar results corresponding to the time-harmonic excitation are also given, which are quite different from the conclusions derived by Silver.

In this paper, the problem of free electron laser excitation by a relativistic electron beam passing through background plasma with ion acoustic wave as wiggler is studied. Under the case of Compton and Raman regime, both the linear dispersion relation and the growth are presented. The analysis makes no assumption on the relative relation of the beam density and the background plasma electron density, and the result is also fit to both ion ripple laser case and the large amplitude ion acoustic wave case.

Experimental studies of light amplification with dynamic multiwave gratings recorded in an acceptor-donor-substituted azobenzene-doped poly(methyl methacrylate) thin film by multi-wave mixing are reported. The amplification gain was measured to be as high as 6.7, and the operation at red light wavelength decreases the absorption losses.

Based on the double-injection effect, the dual-mode interference principle and the free-carrier plasma dispersion effect, a double-injection bifurcation optical active switch integrated on silicon-on-insulator has been proposed and fabricated. Its insertion loss and crosstalk are measured to be less than 5.32 and -14.4dB, respectively, at wavelength 1.3μm and the total switching current 90mA. Response time is about 180ns.

The increase of absorption loss in photosensitivity enhanced optical fiber via H₂ loading induced in the making process of fiber grating was measured. From the results it can be seen that hydroxyl induced by exposing the H₂ loaded GeO₂-doped optical fiber to 248nm light causes large absorption loss at 1.4μm. A reaction model is postulated to describe the process that leads to the loss increase and photosensitivity enhancement in GeO₂ -doped optical fiber.

X-ray nonspecular scattering method is used to study the structures of Mo thin films fabricated with magnetron sputtering under different Ar pressures. The results show that with the increase of Ar pressure, the density of amorphous Mo film decreased; the surface roughness of the films increased, while the surface coherent length decreased. The abnormal glow discharging in the sputtering processes interprets the observed results well.

In the properly designed Mo-Cu multilayered films by free energy concern, several new metallic glasses, were obtained by ion mixing in an immiscible Mo-Cu system. To elucidate the unexpected glass formation, a Gibbs free energy diagram was constructed on the basis of Miedema’s model, with a special consideration to include the interfacial free energy into the initial state of the multilayered films. It turned out that the interfacial free energy raised the multilayered films to an energetic state higher than that of the amorphous phase in a specific range depending on the fraction of interfacial atoms and that the ion-induced glass transition observed in this system was generated by the interfaces.

The melt spun Cu₈₈Co₁₂ has obvious giant magnetoresistance (GMR) after annealed at 450°C for 0.5h. By means of filed ion microscope with atom probe (FIM-AP), the spherical Co precipitates were clearly observed in this alloy for the first time. The average diameter of the particles is about 1.7nm in the specimen annealed at 450°C for 2h, which has the highest GMR of 30.7% at 1.5K. By using both persistence size method and direct measurement method on micrographs from FIM, the size distribution of the Co particles was determined. These results are very useful for testing the present theory on the relationship between GMR and microstructure.

In this paper, a derivation of the macroscopic mean field theory of the cellular automaton (CA) model of highway traffic flow starting from the microscopic dynamical point of view is presented. Starting from an equation describing the time evolution of the Boolean state variable at each site of the basic CA model, and using a two-site approximation for the multi-site correlation functions, a dynamical mapping between the macroscopic average speeds v(t + 1) and v ( t ) at different time can be derived. Mean field results consistent with the simulation data are obtained by considering the attractors of the mapping and their corresponding basins.

In this paper, the free energies of solid and liquid phase of two-dimensional Collins ternary system have been given, the equations of phase equilibrium between solid and liquid have been found. The “cigar” type of solid-liquid phase transition has been discussed. The phase diagrams obtained are similar to those of the three-dimensional true alloy system.

The damage removal and strain relaxation in the As⁺-implanted Si_0.57Ge_0.43 epilayers were studied by double-crystal x-ray diffractornetry and transmission electron microscopy. The results presented in this paper indicate that rapid thermal annealing at temperatures higher than 950°C results in complete removal of irradiation damage accompained by the formation of GeAs precipitates which enhance the removal process of dislocations.

A new effect, spin-polarized magnetovoltage (MV) effect, is observed in an 81NiFe/A1₂O₃/Fe junctions with cross-strip-electrode configuration. When one ferromagnetic electrode carries current, a voltage can be found between the ends of the other ferromagnetic electrode, and it varies with the magnetization process of the two ferromagnetic electrodes. The MV ratio, which is much larger than the magnetoresistance ratio for the same junction, has reached 53% at room temperature.

The static nonlinear magnetic response of randomly pinned flux-line lattice in a type-II super-conductor has been investigated using variational replica-symmetry-broken method. A peak in the curve of susceptibility as a function of external magnetic field is found. When the magnetic field is low, there is a softening in the susceptibility as an effect of pinning potential with nonzero correlation length. At some critical magnetic field, the softening changes into hardening. After reaching the maximum in hardening, the susceptibility decreases to its value of piire states with the increase of magnetic field.

The oxidation state of Cu in the homologous Tl₂Ba₂Ca_n-1Cu_nO_2n+4+δ(n = 1 - 4) series has been analyzed in terms of the bond valence sums. It is found that the totally mobile hole concentration n_H,t of the type-I CuO₂ planes at the optimal level increases with increasing number of CuO₂ layers per unit cell from 1 to 3, and the largest n_H,t is observed to be 0.474 when n = 3, which just corresponds to the highest T_c in the bilayer T1-based materials, and then it decreases with the increase of n. It is indicated that the correlation between the maximum value of T_c and n is similar to that between n_H,t and n.

Measurement and characterization were carried out on Cu-doped and undoped La₂CuO_4+δ samples prepared under the same conditions. The magnetization measurement on the Cu-doped La₂CuO_4+δ sample shows coexistence of long-range antiferromagnetic order and superconductivity. A stripe-like structure was observed at room temperature on the ab-plane of Cu-doped La₂CuO_4+δ sample by transmission electron microscope. While for the undoped La₂CuO_4+δ sample no such behavior or structure feature was found. In this letter, these phenomena were discussed in terms of phase separation.

The electric and magnetic properties in granular perovskite La_0.8Sr_0.2MnO₃ have been investigated. A giant magnetoresistance (GMR) has been observed at temperatures well below T_C, the Curie temperature, associated with crystal intrinsic magnetic properties. The granular GMR effect is also isotropic but shows some characteristics different from those in the films and crystals of similar perovskites. This suggests an effect of interfacial spin-dependent tunneling in the granular perovskite at temperatures much lower than T_C. In addition, with the reduction of grain size, an evident superparamagnetic behavior has been observed.

Superconducting quantum interference devices (SQUlDs) using YBa₂Cu₃O₇step-edge grain boundary junctions on LaAlO₃ substrates were fabricated. The I-V and V-Ф characteristics of these step-junction dc-SQUIDS were studied. A modulation voltage exceeding 16μV was attained with L_s = 60pH at 77K. At 77K, a square washer configuration with inductance L_s = 150pH yields flux noise of about 5.08 x 10^-5Ф₀/√Hz at frequencies above 100Hz, increasing to 1.1 x10^-4Ф₀/√Hz below 1 Hz. The corresponding magnetic field and energy resolution were 270 fT/√Hz and 3.68x10^-29J / Hz respectively, above 100 Hz, and increasing to 710 fT/√Hz and 1.8 x10^-28 J/Hz over a signal frequency range to below 1 Hz.

We elaborate the quantum Yang-Mills inflationary model. We find that a slow-rolling inflation occurs naturally in the presence of a thermal component produced by the decay of Yang-Mills condensate. The magnitude of cosmic perturbation is found to be closer to the observed value than that of scalar inflationary models.