[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] Taking the preparation of zirconium hydride powder as an example, considering the potential factors that may reduce the product quality, the quality control scheme and tools are developed, in terms of methodology, human and equipment, which are implemented to gain 100% conformity. (authors)

[en] In this paper, the interaction behavior of U-Mo/Al was studied with the diffusion-couple method, and the couple was continuously jointed by hot-pressing with special device. Annealing experiments were accomplished in a vacuum hot-pressing furnace, and at 550∼570℃ for 5∼21 hours. The results show that the morphology and composition of interaction Layer depend on the interaction layer thickness. The content of U (Mo) and Al is mutational at the interface of U-Mo/interaction layer/Al. The layer close to U-Mo side is mainly composed of product (U, Mo)Al₃, while the Al side is composed of (U, Mo)Al₄ and UMO₂Al₂₀. Diffusion process of U-Mo/Al is Al immigrating over the Al/U-Mo original interface into U-Mo side and reacting with U-Mo, subsequently the interaction layer is growing into Al. (authors)

[en] As each solar cycle progresses, remnant magnetic flux from active regions (ARs) migrates poleward to cancel the old-cycle polar field. We describe this polarity reversal process during Cycle 24 using four years (2010.33-2014.33) of line-of-sight magnetic field measurements from the Helioseismic and Magnetic Imager. The total flux associated with ARs reached maximum in the north in 2011, more than two years earlier than the south; the maximum is significantly weaker than Cycle 23. The process of polar field reversal is relatively slow, north-south asymmetric, and episodic. We estimate that the global axial dipole changed sign in 2013 October; the northern and southern polar fields (mean above 60° latitude) reversed in 2012 November and 2014 March, respectively, about 16 months apart. Notably, the poleward surges of flux in each hemisphere alternated in polarity, giving rise to multiple reversals in the north. We show that the surges of the trailing sunspot polarity tend to correspond to normal mean AR tilt, higher total AR flux, or slower mid-latitude near-surface meridional flow, while exceptions occur during low magnetic activity. In particular, the AR flux and the mid-latitude poleward flow speed exhibit a clear anti-correlation. We discuss how these features can be explained in a surface flux transport process that includes a field-dependent converging flow toward the ARs, a characteristic that may contribute to solar cycle variability

[en] U-Mo alloy fuel is the research focus on new-type fuel for research and test reactor. The research status and progress of U-Mo alloy fuel in Nuclear Power Institute of China (NPIC) was introduced in this paper. U-Mo alloy dispersion-type fuel was started to study since 2006. In several years, much works have been done, including the smelting of U-Mo alloy, the preparation of γ-phase U-Mo alloy powder, the fabrication of (U-Mo)-(Al-Si) dispersion fuel plate, the compatibility between U-Mo alloy and cladding or matrix materials such as pure Al, Al-Si alloy, pure Nb, Zr alloy and pure Mg. In addition, the methods of elements analysis and non-destructive examination for U-Mo alloy fuel plate were studied. Based on these research works, the improved U-Mo dispersion fuel plates have been fabricated. The NPIC plans to master the fabrication technology of improved (U-Mo)-(Al-Si) dispersion fuel plates which satisfy the technical requirements by 2010. (authors)

[en] Full density Nb₂O₅-BaO-Na₂O-SiO₂ Glass-ceramics, which could be used as the dielectric energy-storage materials to fabricate high energy density devices, were prepared by means of rapid quenching and succeeding annealing under different temperature. DTA and X-ray diffraction analysis showed that NaBa₂Nb₅O₁₅ with tungsten bronze structure and NaNbO₃ with perovskite structure were formed as the dielectric phases from the glass matrix at above 750 deg. C. Dielectric constant of the crystallized glass-ceramics were measured at the frequency from 100 Hz to 100 kHz under the testing temperature from -40 to 150 deg. C. The results indicated that theoretical energy storage density of the material crystallized at 800 deg. C could reach up to 1.87x10⁶J/m³, which would be suitable to be used as the innoxious dielectric media for high-energy storage capacitors.

[en] Two extrapolation models of the solar coronal magnetic field are compared using magnetogram data from the Solar Dynamics Observatory /Helioseismic and Magnetic Imager instrument. The two models, a horizontal current–current sheet–source surface (HCCSSS) model and a potential field–source surface (PFSS) model, differ in their treatment of coronal currents. Each model has its own critical variable, respectively, the radius of a cusp surface and a source surface, and it is found that adjusting these heights over the period studied allows for a better fit between the models and the solar open flux at 1 au as calculated from the Interplanetary Magnetic Field (IMF). The HCCSSS model provides the better fit for the overall period from 2010 November to 2015 May as well as for two subsets of the period: the minimum/rising part of the solar cycle and the recently identified peak in the IMF from mid-2014 to mid-2015 just after solar maximum. It is found that an HCCSSS cusp surface height of 1.7 R _⊙ provides the best fit to the IMF for the overall period, while 1.7 and 1.9 R _⊙ give the best fits for the two subsets. The corresponding values for the PFSS source surface height are 2.1, 2.2, and 2.0 R _⊙ respectively. This means that the HCCSSS cusp surface rises as the solar cycle progresses while the PFSS source surface falls.

[en] An effective technique for making nonmagnetic Ni(W) solid solution using Ni and ammonium paratungstate (APT) as the starting materials was developed. It was found that powder particles using APT as the W source have larger contact area between W and Ni and higher activity, which is conducive to the mutual diffusion between Ni and W, leading to a faster solid phase reaction and higher content of W diffused into Ni. The value of magnetic saturation (Ms) of Ni(W) solid solution powders using APT as the tungsten source is nearly zero under the suitable diffusion condition (550 °C × 2 h +800 °C × 2 h in hydrogen), much lower than that when using W powder. (paper)

[en] An effective technique for making nonmagnetic WC based cemented carbide by using Ni(W) solid solution manufactured from ammonium paratungstate(APT) as the binder was developed. It was found that powder particles using APT as the W source had larger contact area between W and Ni and higher activity, which was conducive to the mutual diffusion between Ni and W, leading to a faster solid phase reaction and higher content of W diffused into Ni. And the mechanical and nonmagnetic properties of WC based cemented carbide derived from nonmagnetic Ni(W) solid solution as the binder are much better than those derived from pure Ni as the binder. (paper)

[en] The diffusion behavior between U-10Mo and Al-Si alloys was studied with diffusion-couple method. The couple was annealed in a high vacuum heat-pressure furnace at 555, 570, 580, 590 and 595 degree C, respectively for 5-10 h. Annealing conditions have a significant effect on interaction-layer thickness. When temperature is lower than 580 degree C with pressuring, the thickness suddenly decreases then slowly increases with the Si content increasing; however, when temperature is higher than 580 degree C the thickness increases with the Si content increasing. Interaction layer with higher Si content which thickness is lower than that with lower Si content is composed of three layers. Si-rich layer with the composition of (U, Mo)(Al, Si)_x(x ≤ 3) closes to U-10Mo side, Si-poor layer with the composition of (U, Mo)(Al, Si)_x(x>3) closes to Al-Si side. (authors)