For M×N spectral matrix, a kind of operation ʘ which satisfies combination law (aʘb)ʘc=aʘ(bʘc) is introduced. The discrete multi−component zero-curvature equation is deduced by using the new operation ʘ, and a simple method for constructing discrete multi-component integrable hierarchy is proposed. As its application, the multi-component Toda hierarchy and its two kinds of integrable couplings are worked out.

We study the effects of viscous dissipation on flow and heat transfer in a thin liquid film on an unsteady stretching sheet. A general surface temperature is taken into consideration. The velocity and temperature fields are solved using the homotopy analysis method. The results show that the increasing values of the Eckert number can increase temperature distribution and the heat transfer rate.

The Schrödinger equation with the Manning-Rosen potential is studied by working in a complete square integrable basis that carries a tridiagonal matrix representation of the wave operator. In this program, solving the Schrödinger equation is translated into finding solutions of the resulting three-term recursion relation for the expansion coefficients of the wavefunction. The discrete spectrum of the bound states is obtained by diagonalization of the recursion relation with special choice of the parameters and the wavefunctions is expressed in terms of the Jocobi polynomial.

We investigate how an initial thermo vacuum state, in the context of thermo field dynamics, evolves in a single-mode amplitude dissipative channel, and find that in this process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic.

A new implementation of high-dimensional quantum key distribution (QKD) protocol is discussed. Using three mutual unbiased bases, we present a d−level six-state QKD protocol that exploits the orbital angular momentum with the spatial mode of the light beam. The protocol shows that the feature of a high capacity since keys are encoded using photon modes in d-level Hilbert space. The devices for state preparation and measurement are also discussed. This protocol has high security and the alignment of shared reference frames is not needed between sender and receiver.

Bound and resonant states of the Hulthén potential are studied. The complex scaling method is used to achieve the energy spectrum. The oscillator basis is used to expand the radial wave function. Conforming to the standard feature of the complex scaling method, the bound energies do not change and the continuums change with the rotational angle. With tables and graphs, the interesting properties of the energy spectrum for various physical parameters are presented. The Gauss quadrature integral approximation is used to deal with the potential integral term.

We demonstrate that the projective synchronization can be observed in coupled fractional-order chaotic systems. A new systematic and powerful coupling scheme is developed to investigate the projective synchronization via the open-plus-closed-loop control, which allows us to arbitrarily manipulate the scaling factor of projective synchronization. The proposed scheme is proved analytically on the basis of the stability theorem of the fractional differential equations. Numerical simulations on the fraction-order chaotic Chen system are presented to justify the theoretical analysis.

Accelerator mass spectrometry (AMS) is one of the most promising methods to detect minute amounts of ¹⁸²Hf. However, the sensitivity of 5×10⁻¹¹ for ¹⁸²Hf/¹⁸⁰Hf obtained previously by the AMS method at China Institute of Atomic Energy (CIAE) cannot meet the requirement of some applications. We present some new improvements of measurement method for AMS measurement of ¹⁸²Hf at the CIAE HI−13 tandem accelerator system. As a result, a sensitivity of 1.0×10^-11 for ¹⁸²Hf/¹⁸⁰Hf is achieved.

Band interaction between the chiral doublet bands based on πh_11/2⊗νh⁻¹_11/2 configuration is investigated in the particle rotor model with different triaxial deformation γ. The variation of chiral partner states with γ values is understood qualitatively based on the basic picture of two interaction levels, which is confirmed further by the calculated overlap integral of wave functions at different γ values. It is found that the interaction strengths of chiral partner states are obviously different for odd spins and even ones.

Half-lives of proton radioactivity are investigated with a deformed density-dependent model. The single folding potential which is dependent on deformation and orientation is employed to calculate the proton decay width through the deformed potential barrier. In addition, the spectroscopic factor is taken into account in the calculation, which is obtained in the relativistic mean field theory with NL3. The calculated results of semi-spherical nuclei are found to be in good agreement with the experimental data, and the results of well-deformed nuclei are also satisfactory. Moreover, a formula for the spherical proton emission half-life based on the Gamow quantum tunneling theory is presented.

Within the framework of Skyrme energy density formalism, we investigate the role of surface corrections on the fusion of colliding nuclei. The coefficient of surface correction is varied between 1/36 and 4/36, and its impact is studied on about 180 reactions. The detailed investigations indicate a linear relationship between the fusion barrier heights and strength of the surface corrections. Our analysis of the fusion barriers advocate the strength of surface correction of 1/36.

By using a suitable set of the surface energy coefficient, nuclear radius, and universal function, the original proximity potential 1977 is modified. The overestimate of the data by 4% reported in the literature is significantly reduced. Our modified proximity potential reproduces the experimental data nicely compared to its older versions.

Beam dynamics and rf designs of a 104 MHz ladder type IH-RFQ (L-IH-RFQ) accelerator are finished at Peking University for the acceleration of ¹⁴C⁺ from 40 keV to 500 keV. As a specific feature, the output beam energy spread is as low as 0.6% achieved with the internal discrete bunching method, which makes potential applications of RFQ feasible, such as accelerator mass spectrometry and ion implantation. Tolerances of the beam dynamics design are studied by means of changing the input beam parameters, and the results are quite satisfying. On the other hand, the L-IH-RFQ structure is employed, taking advantage of its mechanical stability and the absence of inter-electrode voltage asymmetry. Radio-frequency properties are studied and optimized for reducing power loss with Microwave Studio (MWS). Tuning of the field flatness and frequency is investigated in principle.

We demonstrate an experimental observation of coherent population trapping-Ramsey interference in cold ⁸⁷Rb atoms by employing the time-domain separated oscillatory fields' method. The interference fringe with line width of 80 Hz is obtained. We propose a novel method to measure the cold atom number. The measurement is insensitive to the pump beam intensity, the single photon detuning and even the initial state population. We use this method to normalize the interference signal and to improve the signal-to-noise ratio significantly.

An experimental measurement of radiatively heated iron plasma transmission spectra was performed on Shenguang II laser facility. In the measurement, the self−emission spectrum, the backlighting spectrum, and the absorption spectrum were imaged with a flat filed grating and recorded on a gated micro channel plate detector to obtain the time-resolved transmission spectra in the range 10-20 Å (approximately 0.6-1.3 keV). Experimental results are compared with the calculation results of an unsolved transition array (UTA) code. The time-dependent relative shift in the positions of the 2p-3d transmission array is interpreted in terms of the plasma temperature variations.

The electron energy loss spectra for the valence-shell excitations of oxygen are measured at an incident electron energy of 2500 eV and at scattering angles from 4^° to 8.5^°. The dipole−forbidden and octupole-allowed transition of the A'³Δ_u ←X³Σ_g^- is observed from the measured spectra, and it is found that the peak profile of the A'³Δ_u ←X³Σ_g⁻ excitation can be well represented by a Gaussin function. The energy position of 6.007±0.008 eV and Franck−Condon linewidth of 1.312±0.020 eV of the A'³Δ_u ←X³Σ_g⁻, which are independent of the scattering condition, have been determined for the first time. The peak profiles of the A'³Δ_u ←X³Σ_g⁻ determined in this work provide a possibility to realize the spectral decomposition method of unfolding the Herzberg pseudocontinuum proposed by Campbell ıt et al. [Phys. Rev. A 61 (2000) 022706]

The differential and integral cross sections for electron impact excitation of lithium from the ground state 1s²2s to excited states 1s²2p, 1s²3l (l=s, p, d) and 1s²4l (l=s, p, d, f)at incident energies ranging from 5 eV to 25 eV are calculated by using a full relativistic distorted wave method. The target state wavefunctions are calculated by using the Grasp92 code. The continuum orbitals are computed in the distorted-wave approximation, in which the direct and exchange potentials among all the electrons are included. A part of the cross sections are compared with the available experimental data and with the previous theoretical values. It is found that, for the integral cross sections, the present calculations are in good agreement with the time-independent distorted wave method calculation, for differential cross sections, our results agree with the experimental data very well.

We study the elastic scattering of atomic argon by an electron in the presence of a bichromatic laser field in the second Born approximation. The target atom is approximated by a simple screening potential. We explore the dependences of the differential cross sections on the relative phase φ between the two components of the radiation field and discuss the influence of the number of photons exchanged on the phase-dependence effect. Moreover, for different scattering angles and incident electron energies, the differential cross sections are notably different.

Inelastic mean free paths (MFPs) of 0.05-10 MeV protons in a group of 10 organic compounds are systematically calculated. The calculations are based on the method newly derived from the Ashley optical-data model and from the higher-order correction terms in stopping power calculations. Especially, in this method the new and empirical Bloch correction for the inelastic MFP is given. An evaluation for the optical energy loss function is incorporated into the present calculations because of the lack of available experimental optical data for the considered organic compounds expect for kapton. The proton inelastic MFPs for these 10 organic compounds in the energy range from 0.05 to 10 MeV are presented here for the first time, and the combination of these inelastic MFP data and our previous data of stopping power calculation for these bioorganic compounds may form a useful database for Monte Carlo track-structure studies of various radiation effects on these materials.

By using the micro-channel plate position sensitive detector with the delay-line anode we measure the single electron detachment cross sections for some transition elements in collision with Ar in the energy region 10-30 keV. These single electron detachment cross sections perform as velocity and electron affinity dependences. The experiments are carried out using the growth rate method.

The dynamics of nonlinear magnetoinductive waves in a two-dimensional monoatomic lattice of Split ring resonators (SRRs) with Kerr nonlinear interaction between nearest neighbors is studied analytically. The soliton excitation genuine of the discreteness and nonlinearity in such a system based on an extended quasidiscreteness approach are obtained.

We fabricate 1.5 μm InGaAsP/InP tunnel injection multiple−quantum-well (TI-MQW) Fabry-Perot (F-P) ridge lasers. The laser heterostructures, including an inner cladding layer and an InP tunnel barrier layer, are grown by metal-organic chemical-vapor deposition (MOCVD). Characteristic temperature T₀ of 160 K at 20°C is obtained for 500−μm−long lasers. T₀ is measured as high as 88 K in the temperature range of 15−75°C. Cavity length dependence of T₀ is investigated.

We demonstrate a diode-pumped cw mode-locked Nd:YAG by an acousto-optic mode locker. A mode-locked pulse with duration of 345 ps and output power of 12 W is obtained. The resonator design shows three advantages: a larger mode volume, high stability against thermal lens fluctuations, and excellent beam quality with TE₀₀ mode. Different from previous active mode locking designs, we employ a frequency stabilizer and a phase-lock loop circuit to ensure the mode locking stable operation.

We report an LD side-pumped continuous-wave passive mode-locked Nd:YAG laser with a Z-type folded cavity based on a semiconductor saturable absorber mirror (SESAM). The average output power 2.95 W of mode-locked laser with electro-optical conversion efficiency of 1.3% and high beam quality (M_x²=1.25 and M_y²=1.22) is achieved. The repetition rate of mode-locked pulse of 88 MHz with pulse energy of 34 nJ is obtained.

We present an 880-nm laser-diode partially end-pumped Nd:YVO4 slab cw laser with output 126.7 W by using a hybrid resonator. The slop efficiency and optical-to-optical efficiency with respect to absorbed pumping power are 73.2% and 58.7%, respectively. At the output power of 100 W, the beam propagation M² factors are 1.1 in the unstable direction and 1.15 in the stable direction.

Ta₂O₅ films are deposited on fused silica substrates by conventional e−beam evaporation. Surface topography and chemical composition are examined by atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). The calculation of electron structures of Ta₂O₅ and Ta₂O_5−x is attempted using a first-principle pseudopotential method within the local density approximation. The laser-induced damage threshold (LIDT) is performed at 1064, 532 and 355 nm in 1-on-1 regime, respectively. The results show that the LIDT increases with the wavelength increasing, which is in agreement with the wavelength effect. However, the LIDT results are not consistent with the empirical equation (I(λ)=aλ^m), which may be attributed to the intrinsic absorption of Ta₂O₅ at the wavelengths of 532 or/and 355 nm. Moreover, different damage morphologies are observed when the films are irradiated at different wavelengths. It is concluded that the laser damage at 1064 nm is the defect dominant mechanism and at 355 nm it is the intrinsic absorption dominant mechanism, whereas at 532 nm it is the combined defect and intrinsic absorption dominant mechanism.

InAs infrared-sensitive solar cells are fabricated by using the films grown by the liquid phase epitaxy technique. The film microstructures are characterized by x-ray diffraction and scanning electronic microscopy. The current-voltage characteristics of the solar cells in the dark and under AM1.5 illumination at 300 K and 77 K are discussed. The conversion efficiency of p-InAs/n-sub InAs cells decreases when the thickness of the p-type film changes from 1.7 μm to 3.5 μm, which is caused by the reduced effective photons near p−n junction. The p-InAs/n-InAs/n-sub InAs solar cell with the conversion efficiency of 7.43% in 1-2.5 μm under AM1.5 at 77 K is obtained. The short circuit current density increases dramatically with decreasing temperature due to the weakened effect of phonon scattering.

A mobile molecular Doppler wind lidar (DWL) based on double-edge technique is presented for wind measurement at altitudes from 10 km to 40 km. A triple Fabry-Perot etalon is employed as a frequency discriminator to determine the Doppler shift proportional to the wind velocity. The lidar operates at 355 nm with a 45-cm aperture telescope and a matching azimuth-over-elevation scanner that can provide full hemispherical pointing. In order to guarantee the wind accuracy, different forms of calibration function of detectors in different count rates response range would be especially valuable. The accuracy of wind velocity iteration is improved greatly because of application of the calibration function of linearity at the ultra low light intensity especially at altitudes from 10 km to 40 km. The calibration functions of nonlinearity make the transmission of edge channel 1 and edge channel 2 increase 38.9% and 27.7% at about 1 M count rates, respectively. The dynamic range of wind field measurement may also be extended because of consideration of the response function of detectors in their all possible operating range.

For the purpose of improving conversion efficiency of solar cells by applying the effect of the wavelength conversion of rare earth ions, photo-luminescence and excitation spectrums of Ce³⁺−Tb³⁺ doped phosphate glass are investigated. Results show that incorporating Ce³⁺ ions to Tb³⁺−doped phosphate glass can greatly increase the absorption coefficient in the range 300-400 nm and then the energy transfer (ET) from Ce³⁺ to Tb³⁺ occurs. In addition, increasing Tb³⁺ concentration in Ce³⁺/Tb³⁺ co−doped phosphate glass can greatly enhance the ET efficiency and 545 nm emission intensity. This shows that Ce³⁺/Tb³⁺ co-doped phosphate glass would be a promising down-shifting material for enhancing the efficiency of solar cells.

Second harmonic generation (SHG) in one-dimensional nonlinear photonic crystals made from periodically alternating ferroelectric and dielectric layers is investigated by means of the transfer matrix method. When tuned at the photonic band gap (PBG) edges, the fundamental wave and second harmonic wave slow down, and the filed enhancement takes place within the nonlinear photonic crystal. The phase mismatching can be compensated for to some extent and the second harmonic process will be enhanced. Numerical results show that the enhancement of SHG in the PBG structure can be up to four orders of magnitude compared with the traditional quasi-phase-matching structure.

We present a novel cluster-seven-core photonic crystal fiber which possesses high nonlinearity and supports the high-power pumping. Its nonlinearity coefficient and effective mode area are calculated by the full vector multipole method. Compared with the single core PCF, the cluster-seven-core photonic crystal fiber can support high-power beam transmitting in the core, and simultaneously has high nonlinearity. This kind of photonic crystal fiber can be applied to the photoelectron-device field.

A broadband highly dispersive fiber based on a dual-concentric-core photonic quasicrystal fiber (PQF) is designed for chromatic dispersion compensation. The fiber is composed of pure silica background and air-holes without doping. The fundamental supermode has a large negative dispersion value of about −9600 ps⋅nm⁻¹⋅km⁻¹ over an optical communication band around 1550 nm and a full width at half maximum (FWHM) of 40 nm. By adjusting the structural parameters, a dispersion of −2250 ps⋅nm⁻¹⋅km⁻¹ around 1550 nm with the FWHM exceeding 280 nm is obtained and the dispersion-bandwidth product can reach 630 GHz⁻¹⋅km⁻¹, which is the highest value of dispersion-bandwidth product from pure silica fibers reported so far.

We report on the realization of optical true-time delay (TTD) by a two-dimensional photonic crystal waveguide (PCWG). Design and fabrication of the PCWG are investigated. The spectral dependence of the group delay is measured by detecting the phase shifts of a 10 GHz modulating signal, and a maximum delay of 25±2.5 ps is obtained.

A simple clock enhanced loop of cascaded electro-absorption modulators (EAMs) and 10 GHz clock recovery modules is presented. The intensity of harmonic of clock-frequency component is analyzed theoretically and verified experimentally in a 160 Gb/s OTDM 100 km transmission system. The 10 GHz clock component is enhanced obviously before launching into the clock recovery module and the recovered clock signal exhibits low rms jitter of <400 fs. Moreover, completely error−free (10^-12) transmission is observed for more than two hours without using forward error correction technology. The power penalty is about 3.6 dB. The proposed loop has merits of enhancing base clock component, simultaneously de-multiplexing and clock recovery, which make the performance of this loop more stable and high suppression of non-target channels.

We demonstrate surface emitting distributed feedback quantum cascade lasers emitting at wavelengths from 8.1 μm at 90 K to 8.4 μm at 210 K. The second−order metalized grating is carefully designed using a modified coupled-mode theory and fabricated by contact lithography. The devices show single mode behavior with a side mode suppression ratio above 18 dB at all working temperatures. At 90 K, the device emits an optical power of 101 mW from the surface and 199 mW from the edge. In addition, a double-lobe far-field pattern with a separation of 2.2^° is obtained in the direction along the waveguide.

Based on the Bragg scattering mechanism of phononic crystals (PCs), a periodic composite material pipe with fluid loading is designed and studied. The band structure of the flexural wave in the periodic pipe is calculated with the transfer matrix (TM) method. A periodic piping experimental system is designed, and the vibration experiment is performed to validate the attenuation ability of the periodic pipe structure. Finally, a finite-element pipe model is constructed using the MSC-Actran software, and the calculated results match well with the vibration experiment. The errors between the theoretical calculation results and the vibration experimental results are analyzed.

Three-dimensional mode coupling around a conical seamount in an ocean waveguide is studied. It is shown that strong mode coupling occurs at the edge of a conical seamount for the incident normal modes with significant amplitudes below the top of the seamount. Therefore, mode coupling is critical for the investigation of the acoustic field around a seamount. In addition, we suggest the use of random discretization for representing smoothly varying bathymetry. For the use of uniform discretization, when the horizontal step size is greater than half of the wavelength, artificial diffraction lobes appear due to coherent backscatter. However, by using the random discretization scheme instead, such artificial diffraction lobes are diffused, resulting in a faster convergence rate.

Location of an airborne source is estimated from signals measured by a horizontal line array (HLA), based on the fact that a signal transmitted by an airborne source will reach a underwater hydrophone in different ways: via a direct refracted path, via one or more bottom and surface reflections, via the so-called lateral wave. As a result, when an HLA near the airborne source is used for beamforming, several peaks at different bearing angles will appear. By matching the experimental beamforming outputs with the predicted outputs for all source locations, the most likely location is the one which gives minimum difference. An experiment is conducted for airborne source localization in the Yellow Sea in October 2008. An HLA was laid on the sea bottom at the depth of 30m. A high-power loudspeaker was hung on a research ship floating near the HLA and sent out LFM pulses. The estimated location of the loudspeaker is in agreement well with the GPS measurements.

We investigate a minute magneto hydro-dynamic mixer with relatively rapid mixing enhancement experimentally and analytically. The mixer is fabricated with brass and polymethyl methacrylate (PMMA) layers. A secondary flow is generated by using the Lorentz force in the fluids. The efficiency of mixing is greatly improved due to the large increase of the contact area between two mixing fluids. The micro particle image velocimetry technique is employed to measure the fluid flow characteristics in the micro-channel. Numerical simulation is performed based on the theoretical model of the computational fluid dynamics and the electromagnetic field theory. The experimental results are in good agreement with the numerical results, which indicates that the mixing area is enlarged by the driving of Lorentz force and the mixing can be enhanced.

The s-polarized surface plasmon polaritons (SPPs) at the interface between dielectric and metamaterial are studied, and the dispersion relations of SPPs are also presented. Using the prism coupling mechanism, we obtain the attenuated total reflection (ATR) spectra in the frequency regime based on the Otto configuration. It is found that the thickness of the dielectric in the configuration and the small damping of the metamaterial affect the coupling strength significantly without changing the coupling frequency. Furthermore, the optimized thickness of the dielectric decreases with a larger damping, and the coefficient F of the metamaterial also determines the coupling frequency and strength.

Structures and dynamics of two-dimensional dust lattices with and without Coulomb molecules in plasmas are investigated. The experimental results show that the lattices have the crystal-like hexagonal structures, i.e. most particles have six nearest-neighboring particles. However, the lattice points can be occupied by the individual particles or by a pair of particles called Coulomb molecules. The pair correlation function is used to compare the structures between the lattices with or without the Coulomb molecules. In the experiments, the Coulomb molecules can also decompose and recombine with another individual particle to form a new molecule.

We study the dynamic behavior of marginal metallic glass-forming liquids Al-Ni-M (M=La, Pr, Nd) in terms of liquid fragility in high and low temperature regions. The liquids are extremely fragile above the liquidus temperature T _liq, but become rather strong near the glass transition temperature T_g. The strength of the transition is inversely correlated with the fragility index at T_g. This relation is discussed in terms of potential energy landscape.

We investigate a peculiar phenomenon by processing ZnO nanobelts with an atomic force microscope (AFM). In the contact mode of AFM, peculiar bending occurs in meso-scale when the nanobelt is applied with force in lateral direction. We study the mechanical properties of ZnO nanobelts under the influence of small size effect, with finite element analysis and mathematical analysis by means of Matlab. Based on this abnormal effect, a novel measuring method is proposed, which allows the surface morphology and surface properties to be characterized at the same time.

Effects of dopant properties on microstructures and the electrical characteristics of poly (3-hexylthiophene) (P3HT) films are studied by doping 0.1 wt% 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F₄−TCNQ), 6,6-phenyl-C₆₁butyric acid methyl ester (PCBM) and N,N'−Diphenyl-N,N'-(m-tolyl)-benzidine (TPD) into P3HT, respectively. The introductions of various dopants in small quantities increase the field-effect mobility and the I _on/I_off ratio of P3HT thin-film transistors. However, each of dopants shows various effects on the crystalline order and the molecular orientation of P3HT films and the performance of P3HT thin-film transistors. These can be attributed to the various size, shape and energy-level properties of the dopants.

MgB₂ tape samples with simultaneous additions of acetone and La₂O₃ were prepared by an in−situ processed powder-in-tube method. Compared to the pure and single doped tapes, both transport J_c and fluxing pinning are greatly improved by acetone and La₂O₃ codoping. Acetone supplies carbon into the MgB₂ crystal lattice and increases the upper critical field, while the La₂O₃ reacts with B to form LaB₆ nanoparticles as effective flux pining centers. The improvement of the superconducting properties in codoped tapes can be attributed to the combined effects of improvement in H_c2 and flux pinning.

We prepare NiZnFe₂O₄ soft magnetic ferrites with different molar ratios with the layered precursor method and investigate their magnetic properties. In the layered precursor, metal ions are scattered on the layer plate in a certain way on account of the effect of lowest lattice energy and lattice orientation. After high temperature calcinations, spinel ferrites with uniform structural component and single magnetic domain can be obtained, and the magnetic property is improved greatly. NiZnFe₂O₄ ferrites prepared have the best specific saturation magnetization of 79.15 emu⋅g⁻¹, higher than that of 68 emu⋅g⁻¹ prepared by the chemical co-precipitation method and that of 59 emu⋅g⁻¹prepared by the emulsion-gel method. Meanwhile the coercivity of NiZnFe₂O₄ ferrites prepared by layered precursor method is 14 kA⋅m⁻¹, lower than that of 50 emu⋅g⁻¹ prepared by the co-precipitation method and that of 59 emu⋅g⁻¹ prepared by the emulsion-gel method.

Excellent magnetocaloric effect with a maximum entropy change and refrigeration capacity of 17.6 J⋅kg⁻¹⋅K⁻¹ and 546 J⋅kg⁻¹, respectively, has been discovered in the Er₆₀Al₁₈Co₂₂ bulk metallic glass under the field of 50 kOe in the temperature range of helium liquefaction. This MCE results from the second-order magnetic transition from the paramagnetic to the ferromagnetic state. Our analysis based on mean-field theory suggests that the excellent MCE is attributed to the strong exchange of magnetic moment in the glassy structure.

We investigate the effects of B₂O₃ addition on structural and magnetic properties of hard magnetic BaFe₁₂O₁₉ particles. The conventional solid state reaction method is used as the synthesis route. Single phase BaFe₁₂O₁₉ could be synthesized with very small amounts of B₂O₃ addition and with calcination at low temperatures (850^°C) in short times (1 h). B₂O₃ addition also improves the magnetic parameters significantly. Remanence magnetization and specific magnetization at 1.5 T increase by ∼40% in magnitude although no significant variations on coercivity is observed.

We fabricate an inverted bottom-emission organic light emitting diode (IBOLED) employing two n-doped layers, i.e., 5 nm lithium carbonate doped PTCDA (1:2 Li₂CO₃:PTCDA) with 5 nm Li₂CO₃ doped BCP (1:4 Li₂CO₃:BCP) on top, where PTCDA and BCP stand for 3, 4, 9, 10 perylenetetracarboxylic dianhydride and bathcuporine, respectively. Compared to the IBOED using a layer of 10 nm 1:4 Li₂CO₃:BCP, the one utilizing the two-layer combination of 5 nm 1:2 Li₂CO₃:PTCDA and 5 nm 1:4 Li₂CO₃:BCP shows decreasing operation voltage and thereby increasing power efficiency, mainly attributed to the higher electron conductivity of 1:2 Li₂CO₃:PTCDA than that of 1:4 Li₂CO₃:BCP. The mechanism of the electron transport through the interface of 1:2 Li₂CO₃:PTCDA and 1:4 Li₂CO₃:BCP is also discussed. We provide a simply and effective structure to enhance the current conduction for IBOLEDs.

We present the design of a planar metamaterial absorber based on lumped elements, which shows a wide-band polarization-insensitive and wide-angle strong absorption. This absorber consists of metal electric resonators, the dielectric substrate, the metal film and lumped elements. The simulated absorbances under two different loss conditions indicate that high absorbance in the absorption band is mainly due to lumped resistances. The simulated absorbances under three different load conditions indicate that the local resonance circuit (lumped resistance and capacitance) could boost up the resonance of the whole RLC circuit. The simulated voltage in lumped elements indicates that the transformation efficiency from electromagnetic energy to electric energy in the absorption band is high, and electric energy is subsequently consumed by lumped resistances. This absorber may have potential applications in many military fields.

The effect of In composition on two-dimensional electron gas in wurtzite AlGaN/InGaN heterostructures is theoretically investigated. The sheet carrier density is shown to increase nearly linearly with In mole fraction x, due to the increase in the polarization charge at the AlGaN/InGaN interface. The electron sheet density is enhanced with the doping in the AlGaN layer. The sheet carrier density is as high as 3.7×10¹³ cm⁻² at the donor density of 10×10¹⁸ cm⁻³ for the HEMT structure with x=0.3. The contribution of additional donor density on the electron sheet density is nearly independent of the In mole fraction.

A novel PMMA/PMGI/ZEP520 trilayer resist electron beam lithograph (EBL) technology is successfully developed and used to fabricate the 150 nm gate-length In_0.7Ga_0.3As/In_0.52Al_0.48As Pseudomorphic HEMT on an InP substrate, of which the material structure is successfully designed and optimized. A perfect profile of T−gate is successfully obtained. These fabricated devices demonstrate excellent dc and rf characteristics: the transconductance G_m, maximum saturation drain−to-source current I_DSS, threshold voltage V_T, maximum current gain frequency f_T derived from h₂₁, maximum frequency of oscillation derived from maximum available power gain/maximum stable gain and from unilateral power−gain of metamorphic InGaAs/InAlAs high electron mobility transistors (HEMTs) are 470 mS/mm, 560 mA/mm, -1.0 V, 76 GHz, 135 GHz and 436 GHz, respectively. The excellent high frequency performances promise the possibility of metamorphic HEMTs for millimeter-wave applications.

Different TiO_x thin films prepared by graded or sufficient oxidization of Ti are applied with Pt or Ag electrode in metal−insulator-metal (MIM) structures for studying the properties and mechanisms of resistive switching. The differences on the mobile oxygen vacancies in TiO_x films and different work functions of the electrode films result in different insulator-metal interface states, which are displayed as ohmic-like or non-ohmic contact. Based on the interface states, the electrical models for MIM devices are analyzed and extracted. The electrode-limited effect and the bulk-limited effect can be unified to explain the mechanisms for resistive switching behavior as the dominant effect respectively in various conditions. All the current-voltage curves of the four kinds of specimens measured in the experiments can be explained and proved in accordance with the theory.

Photon-measurement density function (PMDF), which is the kernel of fluorescence molecular tomography (FMT), largely determines the accuracy of reconstruction result of FMT. Based on the direct method, we propose an expression of PMDF in FMT, which is derived from the finite element method (FEM) solution of the diffusion equation. Compared with the traditional expression based on the perturbation method, the accuracy of expression based on the direct method is shown in theory. Lastly the reconstruction results of phantoms prove this accuracy in experiment.

We report a new ribonucleic acid (RNA) base discrete state model, which was first developed in our lab and designed to provide an efficient and accurate way of representing RNA structures toward RNA three-dimensional structure predictions. Since RNA free energy is largely determined by base pairs and base stackings instead of backbone trajectories, we directly model the RNA base configurations with respect to its previous one along the sequence. This is in sharp contrast with all previous works where the backbone trace was represented. To test how faithfully the discrete model can reproduce the chain trace in continuous space, we randomly select partial chains from the native structure of 23S ribosome RNA and re-grow them. The rms distance of the re-grown structures from the native ones is ∼1.7 Å for an optimized 16−state discrete model and gradually increases to ∼3.3 Å for long chains of length 50. The efficiency is also good, e.g. the program will finish within several tens of second for long loops of length 50. Our model may facilitate the RNA three-dimensional structure predictions in the near future when combined with appropriate free energy evaluation methods.

It is well known that there are only two low-frequency-peaked BL Lac objects (LBLs: BL Lacertae and S5 0716+714) and one flat spectrum radio quasar (FSRQ: 3C 279) among more than 30 active galactic nuclei (AGNs) with detected TeV emissions. We study the spectral energy distribution (SED) of a famous LBL OJ 287, whose light curve has a 12-y period. Using a homogeneous one-zone synchrotron + synchrotron-self Compton model, we model the quasi-simultaneous broad-band SED of OJ 287. With some reasonable assumptions, we extrapolate the model to the high state of OJ 287 and predict its γ−ray emissions. Taking into account the absorption of γ-ray by the extragalactic background light (EBL), we find that the TeV emission of OJ 287 in high state is slightly higher than the sensitivity of H.E.S.S. The study on SEDs of OJ 287 has implications to unveil the origin of jet activity during its 12-y period and the properties of EBL.

The Mars Global Surveyor Mars Orbiter Camera (MOC) took images of a series of strange horseshoe-shaped dunes at the North Martian pole in 2004. These dunes would be formed due to the strong Martian winds whose pattern is different from that on the Earth. We study the cause of the formation of these dunes and make a model for them. In this model, wind speed near the north Martian pole can be evaluated based on the shape of the dunes. We also estimate the surpassing speed of dunes of different sizes.

The neutron star motions are based on the undisturbed finitely thick galactic disk gravitational potential model. Two initial conditions, i.e. the locations and velocities, are considered. The Monte Carlo method is employed to separate rich diversities of the orbits of neutron stars into several sorts. The Poincaré section has the potential to play an important role in the diagnosis of the neutron star motion. It has been observed that the increasing ratio of the motion range vertical to the galactic plane to that parallel to the galactic plane results in the irregularity of neutron star motion.