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Interface width effect on the spherical Rayleigh–Taylor instability in the weakly nonlinear regime is studied by numerical simulations. For Legendre perturbation mode Pn with wave number kn and interface half-width L, the commonly adopted empirical linear growth rate formula γ n em ( L ) = γ n / 1 + k n L is found to be sufficient in spherical geometry. At the weakly nonlinear stage, the interface width affects the mode coupling processes. The development of the mode P 2n is substantially influenced by the interface width. Moreover, the nonlinear saturation amplitude increases with the interface width.

The Rayleigh–Taylor instability at the weakly nonlinear (WN) stage in spherical geometry is studied by numerical simulation. The mode coupling processes are revealed. The results are consistent with the WN model based on parameter expansion, while higher order effects are found to be non-negligible. For Legendre mode perturbation Pn (cosθ), the nonlinear saturation amplitude (NSA) of the fundamental mode decreases with the mode number n. When n is large, the spherical NSA is lower than the corresponding planar one. However, for large n, the planar NSA can be recovered by applying Fourier transformation to the bubble/spike near the equator and calculating the NSA of the converted trigonometric harmonic.

The geometric structure, electronic structure, optical properties and the formation energy of Sb-doped ZnO with the wurtzite structure are investigated using the first-principles ultra-soft pseudo-potential approach of plane wave based upon the density functional theory. The calculated results indicate that the volume of ZnO doped with Sb becomes larger, and the doping system yields the lowest formation energy of Sb on the interstitial site and the oxygen site. Furthermore, Sb dopant first occupies the octahedral oxygen sites of the wurtzite structure. It is found that Sb substituting on oxygen site behaves as a deep acceptor and shows the p-type degenerate semiconductor character. After doping, the electron density difference demonstrates the considerable electron charge density redistribution, which induces the effect of Sb-doped ZnO to increase the charge overlap between atoms. The density of states move towards lower energy and the optical band gap is broadened. Our calculated results are in agreement with other experimental results and could make more precise monitoring and controlling possible during the growth of ZnO p-type materials.

Spin polarized injection into organic and inorganic semiconductors are studied theoretically from the spin diffusion theory and Ohm's law, and the emphases are placed on the effect of the carrier differences on the current spin polarization. The mobility and the spin-flip time of carriers in organic and inorganic semiconductors are different. From the calculation, it is found that current spin polarization at a ferromagnetic/organic interface is higher than that at a ferromagnetic/inorganic interface because of different carriers in them. Effects of the conductivity matching, the spin dependent interfacial resistances, and the bulk spin polarization of the ferromagnetic layer on the spin polarized injection are also discussed.

By orthogonal design theory, technological parameters of the (002)-oriented ZnO film prepared in sol-gel process are optimized. A set of technological parameters for growing highly (002)-oriented ZnO film is obtained. As a result, it is proven that the Zn2+ concentration is the most important factor to grow a highly (002)-oriented ZnO film. We take an appropriate Zn2+ concentration 0.35 mol/L for the aimed film, of which photoluminescence property is better than those of the films derived from other Zn2+ concentrations precursor solution. The Zn2+ concentration either larger or smaller than 0.35 mol/L leads to the (002)-oriented degree decrease of films. By employing an atom force microscope, a hexagonal atom arrangement, which indicates that the film site detected is a ZnO single crystal, is observed in the surface of the highly (002)-oriented film.

Considering the special carriers in organic semiconductors, the spin polarized current under electric field in a ferromagnetic/organic semiconductor system is theoretically studied. Based on the spin-diffusion theory, the current spin polarization under the electric field is obtained. It is found that electric field can enhance the current spin polarization.

By applying the dyadic Green function, the dispersion relation of two-dimensional photonic crystal can be expressed as the cylindrical wave expansions of eigenmodes. With the aid of Green's theorem, the plane-wave coefficients of eigenmodes are reconstructed and employed to formulate the scattering matrix of finite-height two-dimensional photonic crystal. These operations make the convergence rate very rapid, and reduce the dimension of the scattering matrix. As a demonstration, we present the transmission and electromagnetic field distributions for an InGaAsIn photonic crystal, and investigate their convergence.

The switching and threshold properties of quasi-one-dimensional charge-density-wave conductor rubidium blue bronze Rb0.3MoO3 single crystals are investigated in a comparative high and large temperature range. Beyond the limit temperature 50K of Littlewood's theory, even up to about 100K, typical sharp switching to negative or zero differential resistance is observed in E-I characteristic curves. Correspondingly, an obvious switching between two conducting states, from a lowly conducting state to a highly conducting state, is observed in the I-E characteristic curves in the same temperature range. Temperature dependence of the second threshold field E-T2 accompanied by this kind of high field switching behaviour is firstly obtained. These new observations are discussed in the mechanism of the current inhomogeneity and redistribution due to the existence of transverse energy barriers suggested by Zhang et al. [Solid State Commun. 85 (1993) 121].

The flow field of a plasma wake is studied by analysing the saturated ion current of multiple scanning probes with the method of chaos dynamics. The laminated structure of the near-wake is verified. It is observed at x > 250 mm (x is the axis along the flow field) that the far-wake flow field is similar to the free flow field, and turbulent structure exists in the near-wake, but there is no turbulence in the far-wake. The spatially intermittent character of the flow field can be discovered, which seems to produce some relationship between the spatially intermittent character and the turbulence. The results show that the analytic method of chaos dynamics is sensitive to a non-periodic signal.

A weakly nonlinear model is established for incompressible Rayleigh–Taylor instability with surface tension. The temporal evolution of a perturbed interface is explored analytically via the third-order solution. The dependence of the first three harmonics on the surface tension is discussed. The amplitudes of bubble and spike are greatly affected by surface tension. The saturation amplitude of the fundamental mode versus the Atwood number A is investigated with surface tension into consideration. The saturation amplitude decreases with increasing A. Surface tension exhibits a stabilizing phenomenon. It is shown that the asymmetrical development of the perturbed interface occurs much later for large surface tension effect.

The axis of the integrated superluminescent light source was tilted with respect to the output facet normal for lasing suppression. A new phenomenon (lasing suppression) was observed in the tilted integrated device. Three new schemes were proposed and demonstrated further to suppress the lasing by analysing the reason for lasing in the tilted structure. The lasing was suppressed successfully at high pumping levels, and high superluminescent powers (more than 300 mW) were obtained at a pulsed condition with the spectral full width at half maximum of 25-30 nm.

A novel type of integrated InGaAsP superluminescent light source was fabricated based on the tilted ridge-waveguide structure with selective-area quantum well (QW) intermixing. The bandgap structure along the length of the device was modified by impurity free vacancy diffusion QW intermixing. The spectral width was broadened from the 16 nm of the normal devices to 37 nm of the QW intermixing enhanced devices at the same output power level. High superluminescent power (210 mW) was obtained under pulsed conditions with a spectral width of 37 nm.

The azimuthal distributions at mid-rapidity for 40Ar-induced reactions are investigated by nuclear transport theory. The rotation-like behavior which is one of collective motions becomes stronger with the increasing of the impact parameter and weaker with the increasing of the projectile energy. At about 85 MeV/nucleon the rotation-like behavior almost vanishes for 40Ar +27Al system. While the rotation-like behavior becomes weaker and the out-of-plane enhancement of particle emission is revealed with the increasing of target mass. Some quantitative agreements with the experiment data are also obtained.

New calculations for the total reaction cross sections and production cross sections of the energetic particles are carried out via the nuclear transport theory. The experimental total reaction cross sections can be reproduced. In addition, the effects of some ingredients on the total reaction cross sections can be easily analyzed. It is found that the total reaction cross sections are sensitive to the nuclear equation of state below 100 MeV/u and the in-medium nucleon-nucleon cross section in the full energy range addressed. While the π-meson production cross sections can be also calculated.

We developed a simple model to calculate the interaction radii for light neutronrich nuclei based on Coulomb-modified Glauber model. Considering a relation of surface diffuseness of neutron distribution with the neutron separation energy of nucleus, the large increasing of nuclear interaction radii for exotic nuclei (such as 6He, 8He, 11Li, 11Be) on 12C target can be reasonably explained.

An improved microscopic model to calculate the initial exciton number has been developed on the basis of original microscopic model?so-called phase-space model. In our model the particle number p0 and hole number h0 are treated separately and the Vlasov or BUU dynamics is used during the nucleus-nucleus collision instead of simple dynamical process without friction. This model reproduces the experimental results rather well.

The experimental measurement of the total interaction cross sections of N, C, B, and Be isotopes on C-12 target at medium energies is described. A new formula that gives a good description of the energy-range relationship of energetic ions over a wide energy range is presented. The energy calibration of detectors is made by a Monte Carlo simulation method based on this new formula.

A microscopic semi-classical approach, i.e., the linearized Vlasov equation with a collision term treated by the relaxation time approximation, is simply described and is used to investigate the giant dipole resonance (GDR) from hot super heavy compound system. The possibility of such GDR γ rays emission is described also according to the fission delay. For Au+Au system (A = 392) and Xe+U system (A = 374), the temperature dependence of strength distribution of GDR γ rays and the deformation effect on GDR γ rays are discussed in framework of this approach.

We theoretically investigate the electronic structure and spin polarization properties of Na-doped meridianal tris(8-hydroxyquinoline) aluminum (Alq3) by first principles calculations. It is found that the spin density is distributed mainly in the Alq3 part in the Alq3:Na complex. Electron charge transfer takes place from the Na atom to the Alq3 molecule, which induces asymmetric changing of the molecule bond lengths, thus the spin density distribution becomes asymmetric. Spin polarization of the complex originates from the preferable filling of the spin-split nitrogen and carbon p-orbitals because of the different bond length changes of the Alq3 molecule upon Na doping.

We present a design of indirect-drive pulse shape for inertial confinement fusion ignition capsules using laser energy ~1.6 MJ with a moderate gain (~10) on the Shenguang IV laser facility. The trade-off fuel compression (pressure) for resistance to the hydrodynamic instability (HI) in the recent high-foot (HF) implosion campaign [Dittrich T R et al Phys. Rev. Lett. 112 (2014) 055002] is recovered. The proposed design modifies the "main" pulse shape, which features a decompression-recompression step for the fuel shell resulting in higher areal density than that of the "simple" HF design, and thereby approaches the conditions required for ignition avoiding at the expense of more laser energy while holding the HI under control.

Generation of the second harmonic initiated by Bell—Plesset effects in a cylindrical geometry is studied analytically. For an initial single-mode velocity perturbation, the second-order mode-coupling formula is obtained by expanding the perturbation displacement and velocity potential up to the second-order accuracy. It is found that the initially symmetric interface evolves into a significant bubble-spike asymmetric pattern. The second-order solutions clearly show that the amplitude of the spike grows faster than that of the bubble. The temporal evolutions of the amplitudes of the bubble and spike are dependent on the interface velocity V0. The larger interface velocity leads to the smaller amplitude of the perturbation at an arbitrary interface position in a cylindrically convergent geometry.

Effects of a continuous magnetic field in the direction of streaming on the incompressible Kelvin—Helmholtz instability (KHI) are investigated by solving the linear ideal magnetohydrodynamic equations. It is found that the frequency of the KHI is not influenced by the magnetic field. The magnetic field strength effect decreases the linear growth of the KHI, while the magnetic field gradient scale length effect increases its linear growth. The KHI can even be completely suppressed when the magnetic field is strong enough. The linear growth rate approaches a maximum when the magnetic field gradient scale length is large enough.

Magnetoresistance in the structure of ferromagnetic/nonmagnetic/ferromagnetic spin valves are studied theoretically from the spin diffusion theory and Ohm's law. The nonmagnetic layer could be an organic or inorganic semiconductor. Carrier mobility and the spin-flip time in organic semiconductors are different from those in inorganic semiconductors, and effects of these differences on the magnetoresistance in organic and inorganic spin valves are discussed. From the calculation, it is found that the magnetoresistance in inorganic spin valves is higher than that in organic spin valves. Effects of the conductivity matching and spin-dependent interfacial resistances between ferromagnetic and nonmagnetic layers, thickness of the nonmagnetic layer, and the bulk spin polarization of the ferromagnetic layer on the magnetoresistance are also discussed.

The noise suppression effect and its mechanism are investigated for a composite sheet and a composite film made of glass-covered amorphous CoFeSiBCr wires. Both samples show a significant noise suppression effect. The power loss ratio of the composite sheet is above 80% from 1.6 GHz to 8.5 GHz, and that of the composite film is above 70% from 3.2 GHz to 8.5 GHz even if its thickness is only 0.20 mm. The composite sheet demonstrates high real and imaginary permittivity above 30.7 and low real and imaginary permeability below 1.2. The surface resistivities of the two composite samples are as high as about 3×1012Ω/square. The power loss of the composite containing glass-covered wires should be mainly contributed by dielectric loss derived from electronic polarization and relaxation.

The stress-impedance (SI) effect has been observed in as-cast and high-current-density electropulsing annealed Fe73.5Cu1- Nb3Si13.5B9 ribbons. Large SI ratios of -35% and 25% have been obtained in high-current-density electropulsing annealed samples but not in as-cast samples. The SI effect changes drastically with the density of the annealing current and the longitudinally applied stress during the annealing process. The effective permeability has been shown to be responsible for the SI effect.