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[en] We investigate the dynamics of entanglement, quantum correlation and classical correlation for the one-dimensional XY model in a transverse magnetic field. With the initial state polarized along the z axis, we find that the first maximum of the classical correlation between the nearest neighbor sites peaks around the critical point for large anisotropy parameter. It may indicate the quantum phase transition. For all kinds of correlation, we find that their behaviors between the nearest neighbor sites are significantly different from those of the next-nearest neighbor sites. (authors)

[en] In order to control effectively the nitrogen content of the zirconium alloy powder with strong activity, the research about the influencing factors during the process of the zirconium alloy preparation were carried out. Through analyzing the influencing factors during the process of the zirconium preparation, reducing the transient cracking temperature by adding alcohol medium when cracked the zirconium alloy, and removing the adsorbate under high temperature and black vacuum conditions, as well as protecting the zirconium hydride out of the furnace were studied. The combination nitrogen content of the powder and the total nitrogen content were measured by chemistry analysis technique, and high temperature and fusion method respectively; and the powder activity were analyzed. The results shown that adding alcohol medium is an effective method to reducing the nitrogen content of zirconium alloy; and removing the adsorbate under high temperature and black vacuum conditions can not realize the experimental purpose; moreover the method of protecting the zirconium hydride out of the furnace have some effective on reducing the nitrogen content of zirconium alloy, however, the result is not stable clearly. In this present study, it is found that a great deal physics-adsorption nitrogen among zirconium hydride have a direct influencing to the nitrogen content of zirconium alloy, and the transient cracking temperature is also an important influencing factor to it. (authors)

[en] It is shown that the decoherence-free subspace (DFS) of practical multiphoton polarization cannot avoid exponential decoherence even in the same extra environment if the photons are frequency anticorrelated. The reason lies in the fact that the condition of collective decoherence is not satisfied in this case. As an example, the evolution of a biphoton decoherence-free state is given. A possible solution for a feasible multiphoton DFS state is also given

[en] The effect of temperature on pickling rate of zirconium alloy and the heat release constant was studied in this paper by soaked method. The results show that temperature has exponential effect on pickling rate of zirconium alloy, the rate increases 2.0∼2.5 times 10 at 20∼60. The pickling frequency factor is about 1.18 × 10¹² and the activation energy is about 70 kJ/mol. The pickling reaction of zirconium alloy is exothermic. The reaction temperature increases with the pickling process in which the heat release constant is 760 kJ/mol. (authors)

[en] To understand the zirconium-4 alloy pickling-dynamic behavior, the effect of concentration on pickling rate of zirconium alloy was studied in this paper by socked method. The result shows that zirconium alloy has been strongly corroded in HF which concentration on pickling rate has an exponential relation and keeps to liquid reaction kinetics, and zirconium alloy has been hardly corroded in HNO₃ which concentration on pickling rate has restrained in solution and depresses the rate constant and order of reaction. When the balance is got between the corrosion of HF and the inhibit-corrosion of HNO₃, zirconium alloy surface becomes brightness and undefiled. The steady and reasonable concentration is 4.33 mol/L < HNO₃ < 7.22 mol/L and 0.68 mol/L < HF < 1.60 mol/L, and concentration of HF increase accordingly with concentration of HNO₃. (authors)

[en] The fabrication process for titanium sponge hydride powder was described in this paper. The titanium sponge was hydrided and then ground to 10 mm with crushing mill under high-purity argon atmosphere in the sealed glove box, and then ground to powder with quick-speed crushing mill. The powder should be sieved with mechanism classifier, and then the particle size and impurity (oxygen < 2500 μg/g, nitrogen < 50 μg/g) is analyzed. The H: Ti ratio can be increased from 1.8 to 2.1, and the powder size below 74 μm was about 98.9 %. The annual output of hydride powder product can reach 3 t. (authors)

[en] We present an experiment for preparing a Werner state via spontaneous parametric down-conversion and controlled decoherence of photons in this paper. In this experiment two independent β-barium borate crystals are used to produce down-conversion light beams, which are mixed to prepare the Werner state

[en] We obtain a four-photon polarization-entangled state with a visibility as high as (95.35±0.45)% directly from a single down-conversion source. A success probability of (81.54±1.38)% is observed by applying this entangled state to realize a four-party quantum communication complexity scenario, which comfortably surpasses the classical limit of 50%. As a comparison, two Einstein-Podolsky-Rosen pairs are shown to implement the scenario with a success probability of (73.89±1.33)%. This four-photon state can also be used to fulfill decoherence-free quantum information processing and other advanced quantum communication schemes

[en] To improve uranium homogenization of (U-Mo)-Al fuel, the effect of mixing method and compact end shape on uranium homogenization in fuel meat was studied. Mixing contrast experiment of U-Mo powder and Al-Si powder was made by rotating pan mixer and special tridimensional mixer. Three (U-Mo)-Al fuel compacts of different end shape were respectively pressed by using traditional forming mould for flat angle compact and special forming mould for cutting angle compact. Uranium content of mixing powder was determined by oxidation-reduction titration. Uranium homogenization of fuel plate was detected by γ ray absorption method. Microstructure of the fuel meat was observed by optical microscopy. Results were as follows: Compared with two-dimension mixing, mixing extent of powder was increased by tridimensional mixing, which improved uranium homogenization in homogenous zone of (U-Mo)-Al fuel plate greatly, but there was no positive effect for uranium homogenization in dog-bone zone. Fuel compact end shape has a great influence on uranium homogenization of fuel plate 'dog-bone' zone. Fuel plate made of flat angle compact has obvious 'dog-bone'; 'Dog-bone' extent was aggravated in fuel plate made of double-sided cutting angle compact; Meat thickness tended to small at the end of fuel plate meat made of single-side cutting angle compact, and fractured fuel and long trailing phenomenon was not found, the extent of 'log-bone 'was improved obviously. Verification test results showed that uranium homogenization of (U-Mo)-Al fuel plate was improved greatly by using the tridimensional mixing and single-side cutting angle compact; Uranium homogenization in homogenous zone could be controlled in the range of ±12%, and uranium homogenization in dog-bone zone could be controlled in the range of ±20%. (authors)