[en] The oxidation behavior of γ-TiAl with Ta surface coating fabricated by double glow plasma surface alloying technology was investigated by thermogravimetric method. Oxidation experiments were carried out at 750 °C and 850 °C in air for 100 h. The modification layer was comprised of deposition layer and diffusion layer, which metallurgically adhered to the substrate. Tantalum element decreased with the case depth. The oxidation morphology was studied by a scanning electron microscope and X-ray diffraction. The results highlighted that in the oxidizing process of the oxidation, the phase containing Ta-richer may restrain diffusing outward of the element Al in the matrix. Ti diffused outward, and formed the TiO₂ scales, while the middle layer was rich in Al, and formed the continuous Al₂O₃ scales after oxidation, which was effective to prevent further infiltration of oxygen atoms, and as a result the oxidation resistance increased immensely. - Highlights: • A Ta modified coating was prepared on γ-TiAl using DGP surface alloying technology. • The modification layer metallurgically adhered to the substrate. • The bonding force is about 60 N, satisfying the demands of practical use. • The oxidation resistance increased immensely at 750 °C and 850 °C

[en] Monogamy relations characterize the distributions of entanglement in multipartite systems. We investigate monogamy relations for multiqubit generalized W-class states. We present new analytical monogamy inequalities for the concurrence of assistance, which are shown to be tighter than the existing ones. Furthermore, analytical monogamy inequalities are obtained for the negativity of assistance.

[en] We study the distribution of quantum correlations characterized by monogamy relations in multipartite systems. By using the Hamming weight of the binary vectors associated with the subsystems, we establish a class of monogamy inequalities for multiqubit entanglement based on the $\mathrm{\alpha <!--\; ??\; -->}$th ($\mathrm{\alpha <!--\; ??\; -->}\ge <!--\; ???\; -->2$) power of concurrence, and a class of polygamy inequalities for multiqubit entanglement in terms of the $\mathrm{\beta <!--\; ??\; -->}$th ($0\le <!--\; ???\; -->\mathrm{\beta <!--\; ??\; -->}\le <!--\; ???\; -->2$) power of concurrence and concurrence of assistance. Moveover, we give the monogamy and polygamy inequalities for general quantum correlations. Application of these results to quantum correlations like squared convex-roof extended negativity, entanglement of formation and Tsallis-q entanglement gives rise to either tighter inequalities than the existing ones for some classes of quantum states or less restrictions on the quantum states. Detailed examples are presented.

[en] We present a different kind of monogamy and polygamy relations based on concurrence and concurrence of assistance for multiqubit systems. By relabeling the subsystems associated with different weights, a smaller upper bound of the $\mathrm{\alpha <!--\; ??\; -->}$th ($0\le <!--\; ???\; -->\mathrm{\alpha <!--\; ??\; -->}\le <!--\; ???\; -->2$) power of concurrence for multiqubit states is obtained. We also present tighter monogamy relations satisfied by the $\mathrm{\alpha <!--\; ??\; -->}$th ($0\le <!--\; ???\; -->\mathrm{\alpha <!--\; ??\; -->}\le <!--\; ???\; -->2$) power of concurrence for N-qubit pure states under the partition AB and $C_1\cdots <!--\; ???\; -->C_{N-<!--\; ???\; -->2}$, as well as under the partition $AB{C}_1$ and $C_2\cdots <!--\; ???\; -->C_{N-<!--\; ???\; -->2}$. These inequalities give rise to the restrictions on entanglement distribution and the trade-off of entanglement among the subsystems. Similar results are also derived for negativity.

[en] This paper analyzes the distribution and correlation of electrical field and magnetic field located at the emission domain in the solenoid for the high power foil less diode using over-mode microwave device based the single electronic moving equations. It is confirmed that the electronic beam transmission efficiency is correlated with the reflux. The results from experimental research indicate that distinct power efficiency was explicated for the emission electronic beam from foil less diode with different radius cathode when the guiding magnetic field inside the magnetic solenoid was bigger. When the beam radius was 48 mm the electronic beam transmission efficiency was more than 95%, when the beam radius was more than 90 mm the efficiency was smaller than 75%. (authors)

[en] We investigate the polygamy relations related to the concurrence of assistance for any multipartite pure states. General polygamy inequalities given by the th power of concurrence of assistance is first presented for multipartite pure states in arbitrary-dimensional quantum systems. We further show that the general polygamy inequalities can even be improved to be tighter inequalities under certain conditions on the assisted entanglement of bipartite subsystems. Based on the improved polygamy relations, lower bound for distribution of bipartite entanglement is provided in a multipartite system. Moreover, the th () power of polygamy inequalities are obtained for the entanglement of assistance as a by-product, which are shown to be tighter than the existing ones. A detailed example is presented. (paper)

[en] In this work, a series of nanostructured molybdenum disulfide (MoS₂) with various morphologies, such as spherical, flower-like, coil and hollow were synthesized via a one-step hydrothermal method. The photocatalytic properties of as obtained MoS₂were evaluated by degrading methylene blue (MB) under visible light. Interestingly, the flower-like MoS₂ exhibited the best photocatalytic activities. It is ascribed that the suitable porous structures of flower-like MoS2 can increase the number of exposed active sites, which facilitate the efficient adsorption and transfer of MB to the active sites. Meanwhile, the special structure of flower-like MoS₂ can improve light absorption efficiency owing to the increasing of light paths. Furthermore, its 2D stacked petals possess abundant active sites, which will effectively affect the photocatalytic efficiency. This study indicates that the surface area of nanomaterials is not a dominated factor in photocatalytic performance. The surface morphology has a great influence on the photocatalytic performance, which provides a feasible guide for synthesizing efficient photocatalytic nanomaterials. (paper)

[en] The results on the curvature of a pseudocritical transition line for two-flavor QCD through lattice simulations are presented. The simulations are carried out with Symanzik-improved gauge action and Asqtad fermion action on a lattice ${12}^3\times <!--\; ??\; -->4$ at quark mass $am=0.010$. At the imaginary chemical potentials $a{\mathrm{\mu <!--\; ??\; -->}}_{\mathrm{I}}=0.050$, 0.150, 0.200, 0.225 and 0.250, we investigate the chiral condensate $\stackrel{¯<!--\; ??\; -->}{\mathrm{\psi <!--\; ??\; -->}}\mathrm{\psi <!--\; ??\; -->}$, plaquette variable P and imaginary part of Polyakov loop $\mathrm{I}\mathrm{m}(L)$ and their susceptibilities. Analytic continuation from an imaginary chemical potential to a real one is used to obtain the expression for transition temperature as a function of the chemical potential. The curvature is 0.0326(46). (paper)

[en] The modulation mechanism and RF extraction of an S-band relativistic klystron oscillator were studied via experiment. It is found that intense relativistic electron beams(IREBs) can generate intense current modulation when the IREBs drift through three pillboxes with high coupling. After bunching in the downstream the modulated IREBs can excite high power micro- wave in the triaxial cavity. The RKO has properties of short oscillating time, compact geometry and high beam-wave conversion efficiency. Using a 1 MV/13 kA/40 ns electron beam and leading magnetic field of 0.9 T, 3.5 GW radiated power was extracted in 20 ns FWHM pulses at 2.86 GHz. The beam-wave transition efficiency is 29%, and the instantaneous bandwidth is 2%. The radiated power is 3.4 GW with the efficiency of 26% when repetitive pulse frequency of IREBs is 20 Hz. The experimental results agree well with the simulation ones. (authors)

[en] Spatio-temporal evolutions of the sawteeth activities are measured simultaneously with a 16 channel high spatio-temporal resolution electron cyclotron emission (ECE) heterodyne radiometer on HT-7 and the evolutions of the sawteeth are found to be diffusive in character. By a perturbative analysis, the electron heat diffusivity χ_e inferred by time-to-peak method and Fourier transform shows a good agreement. The value of electron heat diffusivity shows radial asymmetry between the low magnetic field side (LFS) and the high magnetic field side (HFS). It is observed that with the increase in plasma density, the electron heat diffusivity decreases and the confinement of energy is improved. By comparing with χ^pb_e inferred by static power balance analysis, the result indicate that χ^hp_e is larger than χ^pb_e by a factor ranging from 2 to 10. (magnetically confined plasma)