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Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio of electronic temperature to heavy particles temperature. The method of computing the composition of air plasma is demonstrated. After calculating the electrical conductivity from electron temperature 1000 K to 15000 K, the present result is compared with Murphy's study [Plasma Chem. Plasma Process 15 (1994) 279] for equilibrium case. All the calculation is completed at atmospheric pressure. The present results may have potential applications in numerical calculation of non-equilibrium air plasma. [ABSTRACT FROM AUTHOR]

The hardness and ideal strength of P-carbon, i.e., a new carbon phase for the cold-compressed carbon with an orthogonal structure recently proposed and named as P-carbon, are investigated by means of first-principles calculations. The strength calculations reveal that the failure mode in P-carbon is dominated by the tensile type. The ideal tensile strength of P-carbon is calculated to be 76.7 GPa in the [001] direction, which is higher than that of the previously known most stable Z-carbon, of 71.4 GPa. Meanwhile, the theoretical Vickers hardness of P-carbon is estimated as 89 GPa, which is comparable with that of diamond. Especially, two types of bonds in P-carbon with hardness values of 114 GPa and 105 GPa are significantly stronger than those of diamond. The results provide insight into exploration of the ultra-hard P-carbon for potentially technological applications. [ABSTRACT FROM AUTHOR]

Based on the modified isospin-dependent quantum molecular dynamics model, the number of emitted nucleons in a photonuclear reaction is studied with different symmetry potentials and different isospin-dependent nucleon-nucleon (N—N) collision cross sections. It is found that the number of emitted nucleons is sensitive to the isospin-dependent nucleon-nucleon cross section when the photon's energy is higher than 150MeV, while it is insensitive to symmetry potential. The number of emitted neutrons is more sensitive to N—N collision cross sections than that of protons. It is realized that the number of emitted neutrons can be used as a sensitive probe to extract the information of the isospin-dependent N—N cross section at high energy photonuclear reactions. [ABSTRACT FROM AUTHOR]

Numerical method is applied to the investigation of the GAM damping rate with the unite k effects included. It is found that generally the damping rate given by the analytical method is smaller than that given by the numerical method, and the analytical damping rate has good approximation in the high q region (q > 4). The difference between the analytical and numerical damping rates increases with the increasing kri. However, for the short-wavelength case (kri = 0.2), the analytical methods are only good enough around q = 4 because of the slow convergence of Bessel function with the large variable. [ABSTRACT FROM AUTHOR]

Based on both very obvious isospin effect of the neutron-proton number ratio of nucleon emissions (n/p)nucl on symmetry potential and (n/p)nucl's sensitive dependence on symmetry potential in the nuclear reactions induced by halo-neutron projectiles, compared to the same mass stable projectile, probing symmetry potential is investigated within the isospin-dependent quantum molecular dynamics with isospin and momentum-dependent interactions for different symmetry potentials U1sym and U2sym. It is found that the neutron-halo projectile induces very obvious increase of (n/p)nucl and strengthens the dependence of (n/p)nucl on the symmetry potential for all the beam energies and impact parameters, compared to the same mass stable projectile under the same incident channel condition. Therefore (n/p)nucl induced by the neutron-halo projectile is a more favourable probe than the normal neutron-rich and neutron-poor projectiles for extracting the symmetry potential. [ABSTRACT FROM AUTHOR]

A self-similar mode locked fibre laser is studied based on a numerical model. By introducing a dimensionless factor k to characterize the pulse shape, the self-similar pulse evolution, formation and the temporal and spectral shape changes due to the elements in the cavity are investigated throughout the laser cavity. The results show that in the self-similar mode locked fibre laser, self-similar pulse is first formed in the single-mode fibre, which is then amplified in the gain fibre. Gain bandwidth has a small influence on pulse shape, so high energy self-similar pulse can be obtained after amplification. Because net cavity dispersion directly influences the pulse width as well as peak power after compression by a pair of gratings, which can determine the pulse self-similar evolution, it is very important to control the net cavity dispersion to a certain range to obtain self-similar pulses. [ABSTRACT FROM AUTHOR]

The effect of momentum-dependent interaction on the kinetic energy spectrum of the neutron-proton ratio [?](n/p)gas[?]b (Ek) for 64Zn + 64Zn is studied. It is found that [?](n/p)gas[?]b (Ek) sensitively depends on the momentum-dependent interaction and weakly on the in-medium nucleon-nucleon cross section and symmetry potential. Therefore [?](n/p)gas[?]b(Ek) is a possible probe for extracting information on the momentum-dependent interaction in heavy ion collisions. [ABSTRACT FROM AUTHOR]

We demonstrate a compact photonic device based on efficient and wavelength-tunable doubling of an all fibre-format source. Quasi-phase-matched second-harmonic generation in periodically poled lithium niobate is used to generate 90.6mW at 775.9nm with a single-pass conversion efficiency of 14.7%. A tuning bandwidth of 2.1nm and a tuning temperature range of 150.6 ± 1.7°C can be achieved. The Er-doped seed fibre source is amplified by a clad-pumped Er3+/Yb3+ -codoped fibre laser with a high output power up to 2.18 W over a tunable wavelength range from 1535 nm to 1570 nm. [ABSTRACT FROM AUTHOR]

The radio-over-fibre (ROF) uplink, which combines the merit of optical fibre with that of microwave technology, can supply the high capacity of communication. However, there are two major issues: nonlinear distortion of the optical link and the multipath dispersion of the wireless channel, affecting the performance of the system. We propose an equalizer based on hybrid neural networks. The compensation needs no estimation of the channel. The simulated result shows that the ROF uplink can be adequately compensated and the performance of the equalizer depends on the channel noise. [ABSTRACT FROM AUTHOR]

Highly stable frequency-controlled optical frequency combs are key elements of many applications in time-frequency and optical-metrology domains. In this work, we demonstrate a highly stable frequency-controlled erbium-fiber-based optical frequency comb system. Its repetition rate is phase-stabilized to a continuous-wave laser with both an intra-cavity electro-optic modulator and a piezo-transducer; while the carrier-envelope-offset frequency is phase-locked to a radio-frequency signal generator by controlling the pump power. In-loop relative frequency stabilities of the comb are below 1 × 10−16 at 1 s, and integrate down to low 10−20 level at 104 s. The corresponding timing uncertainties are 100–200 as over the full measurement range. [ABSTRACT FROM AUTHOR]

We report fabrication and characterization of organic heterojunction UV detectors based on N,N'-bis(naphthalenl-yl)-N,N'-bis (phenyl) benzidine (NPB)and fullerene C60. The effects of different thicknesses of NPB and C60 layers are studied and compared. Notably, the optimal thicknesses of electron acceptor C60 and electron donor NPB are 40 nm and 80 nm, respectively. The J–V characteristic curves of the device demonstrate a three-order-of-magnitude difference when illuminated under a 350 nm UV light and in the dark at −0.5 V. The device exhibits high sensitivity in the region of 320–380 nm with the peak located around 350 nm. Especially, it shows excellent photo-response characteristic with a responsivity as high as 315 mA/W under the illumination of 192 μW·cm−2 350 nm UV light at −5 V. These results indicate that the NPB/C60 heterojunction structure device might be used as low-cost low-voltage UV photodetectors. [ABSTRACT FROM AUTHOR]

The properties of the Z = 117 isotopic chain are studied within the framework of the axially deformed relativistic mean field theory (RMFT) in the blocked BCS approximation. The ground-state properties, such as binging energies, deformations as well as the possible a decay energies and lifetimes are calculated with the parameter set of NL-Z2 and compared with results from the finite range droplet model. The analysis by RMFT shows that the isotopes in the range of mass number A = 291 [?] 300 exhibit higher stability, which suggests that they may be promising nuclei to be hopefully synthesized in the lab among the nuclei Z = 117. [ABSTRACT FROM AUTHOR]