Starting from a special nonlocal Lie Bäcklund symmetry of the KdV, mKdV. Potential mKdV and singularity manifold equation system, three sets of higher order nonlocal Olver symmetries are reobtained. The soliton solutions of these models can also be obtained from the finite Lie- Bäcklund transformations.

Thin permalloy film with uniaxial anisotropy have been prepared by ion-beam sputtering method. Magnetic field sensors of this type film are composed of four magnetoresistors in Wheastone bridge connection. One may obtain sensitivity more than 10mV/Oe with 10^-5 Oe resolution by suitable design of sensors parameters. A model based on single domain structure and resistance anisotropy effect explains the behavior of the sensors and a method has been developed to reduce the influence of offset voltage and hysteresis to minimum.

In this paper. we discuss the wormhole with the topology of R¹ ⊗ S³ ⊗ T^d in higher order gravitational theory with αR²+βR_μvR^μv term, and derive corresponding wormhole equations as well as their analytical solution.

The nuclear gluon distribution is predicted using the constituent quark model. We point out that the nuclear shadowing and antishadowing depress nuclear gluon field when x < 0.08 and enhance it when 0.08 < x < 0.2.

We observed the phenomena of fusion of fullerenes by laser desorption of chemical adduct R_nC₆₀ (R=C₆H₅CH₂) in negative ion channel. The unstable odd numbered C^-_n clusters (n>50) are readily produced under some experimental conditions, and this can be attributed to their structures possessing cross-section larger than that of the cage-like fullerenes.

The cylindrical plasma-loaded Cerenkov free-electron laser is studied by using fluid theory. It is shown that its working frequency and linear growth rate are higher than that of common Cerenkov free-electron laser, and for the same injection current, the linear growth rate of the system docs not decrease as the gap between the dielectric linear and the elcctron beam increases, but there is an optimum gap value corresponding to the maximum growth rate.

The nonlineat third order optical susceptibility of C₆₀ films on roughed glass plate has been studied by using a mode locked Nd : YAG laser emitting 8ps pulsed at 1.064μm of 0.3 J energy. The large | x ^{( 3 )} ( - 3ω . ω, ω, ω)I = 2 x10^-8 esu for C₆₀ films of 15 μm thickness has been observed, which is 10³ larger than the value in the bulk C₆₀. This is due to surface enhanced effect.

Vibrational densities of states for a diatomic Penrose lattice are calculated. They show apparently acoustic and optical branches. The acoustic branches appear smooth and continuous, while the optical branches are peakrich and have some small gaps. Detailed analysis shows that the density of states in the acoustic branches is attributed to the phonons and the fracton-like excitations and that in the optical branches clue to some localized vibrational model.

Positron annihilation measurements show that the radiation defects and secondary defects in neutron-transmutation-doped (NTD) Si irradiated by two neutron doses can be removed at 600-650°C. The concentration and annealing behavior of V-type and V₂ defects are related to the neutron doses. V₄ appears at 150°C and 450°C - 550°C in NTD Si irradiated by higher neutron dose.

The nanocrystalline titanium samples, having a grain size of about 10nm, are prepared by direct current magnetron sputtering and subsequent in situ compaction. Two new phases are observed by means of transmission electron microscopy, one is a body-centered cubic structure with a lattice parameter of a=0.323nm, the other one is an orthorhombic structure with lattice parameters of a =0.303nm, b=0.391 nm and c =0.488nm. The formation of the two phases is also tentatively discussed.

The self-consistent spin-polarized band-structure calculation of ferromagnetic compound MnBiAl in its low-temperature phase has been performed. In this paper the calculation results arc given. Comparison with the results of MnBi is performed in order to find the effect on electronic structure by doping with AI.

In this letter, we propose a modified attractive Hubbard model at half filling that can exhibit superconductivity through η-pairing mechanism in spin-density wave representation and derive a concise relationship between the energy disparity and the single-particle energy spectrum. This relationship, in the two limits of U, clearly shows that the system does not display superconductivity for very low doping concentration. but demonstrates superconductivity when the doping concentration exceeds a certain critical value. This conclusion is in qualitative agreement with the familiar experiments on high-T_c superconductivity.

Magnetization, Curie temperature and crystallization temperature measurements for amorphous (Fe_1-xNd_x)_100-yB_y alloys with y=6, 18.5 and 25 have been made. Spontaneous magnetization shows a monotonic decrease with x, and the noncollinear spin structures have been proposed to explain the observed results. The composition dependence of Curie temperature is explained by the average molecular-field model. The substitution of small Nd for Fe is found to have a strong enhancement of the thermal stability in amorphous Fe-Nd-B alloys.

The bias field dependence of the rotation direction of the dumbbells, contracted from multi-branched domains, was experimentally studied. Moreover, it was found that the rotation direction of these dumbbells can be reversed by increasing the amplitude of the testing bias pulses with quite narrow width.

Low-frequency phonon spectra in a- SiN_x : H/Si heterostructures have been observed by means of Brillouin light scattering. Measurement of the frequency shift on longitudinal and transverse acoustic phonons as well as on surface phonons enabled us to extract accurately two independent elastic moduli: c₁₁ and c₄₄ deduced from phase velocities of bulk acoustic modes and scattering wavevector, within effective medium approximation.

The a-Ge: H/a-SiN_x :H multiquantum-well structures were prepared by a computercontrolled plasma enhanced chemical vapor deposition method and then crystallized by Ar⁺ laser annealing technique. When the Ge well-layer thickness was reduced to 30Å, the crystallized sample showed a room temperature photoluminescence with a peak at about 2.26eV. Meanwhile some significant characteristics of such a novel Ge nanostructure were also revealed by x-ray diffraction. Possible mechanisms of this visible PL phenomenon have been discussed.

The linear electron-phonon interaction in polymethylmethacrylate (PMMA) doped with electron donor zinc-tetraphenylbenzoporphyrin (ZnTPBP) and acceptor phydroxybenzaldhyde (PHBA), or p-aminoacetophenone (PAAP) was investigated by photon-gated spectral hole-burning (PHB). The aim is to study the factors that affect the linear electron-phonon coupling and the thermal stability of spectral holes in the organic film samples.

This paper discusses the actual possibility of altering artificially certain optoelectronic properties of LiNbO₃ crystals by means of change in lattice site of a few Me³⁺ ions in the crystals. A new lattice site Cr³⁺ defect in Cr-doped LiNbO₃ vapour transport equilibration has been displayed as a practical example.