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[en] Pulse control rod drive mechanism in Xi'an Pulsed Reactor is the key equipment to implement the pulsing operation. It takes ball screws as drive machine. It use pressure cylinder to implement pulse launch of control rod. The feature are: the pulse time of whole journey is short, the configuration is simple, the maintain is convenient. The experiments shows: the largest load is more than 300 N, pulse launch time is less than 100 ms; frequency of pulse launch without stoppage is more than 400 times. And the life of pulse launch is more than 4000 times. The machine has been used for Xi'an Pulse Reactor Successfully
[en] Steady Control Rod Drive Mechanism (CRDM) in Xi'an Pulsed Reactor is the key equipment to implement start-up, shutdown reactor and adjust power of reactor. It takes ball screws as drive machine, engaged electromagnet to drive steady control rod up and down, disengaged electromagnet to drop the control rod rapidly. The structure characteristics, the parameter of design and the test results of CRDM are presented. The machine has been used for Xi'an Pulse Reactor successfully
[en] Highlights: • Ta coating was made on both plate and porous Ti alloy. • The quality of coating depends on H_2 gas flow and T_s. • The corrosion resistance is improved by Ta coating. - Abstract: In this study, high quality Ta coating was made on both plate and porous Ti6Al4V alloy substrates by atmospheric pressure chemical vapor deposition (APCVD) in order to further improve the corrosion resistance and biocompatibility of Ti alloys for medical application. XRD analyses showed that the coatings were mainly composed of Ta with the substrate temperature (T_s) of 1000 °C, 950 °C and 900 °C. The morphology, microstructure and elements composition were characterized by optical microscope, scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy-dispersive spectroscopy (EDS). It was found that the coating surface became much more smooth and uniform at low H_2 gas flow rate of 120 mL/min, and the root-mean-square (RMS) roughness was decreased with the increase of T_s. The wettability of Ta coating was investigated by measuring contact angel of water and α-bromonaphthalene (α-BrNp). The Ta coating with T_s of 950 °C showed the lowest of γ_s, γ_s"d and γ_s"d/γ_s"p, indicating a better hemocompatibility of the Ta coating than that of substrate. The corrosion behavior of the coating was studied by electrochemical test in 0.9% NaCl solution at 37 °C. The Ta coating exhibited higher corrosion potential (E_c_o_r_r) and lower corrosion current density (i_c_o_r_r), indicating an improved corrosion resistance compared with the Ti6Al4V substrate. Ta coating was fabricated not only on the plate substrate, but also on a porous Ti6Al4V substrate. The above results made it possible to develop a novel class of Ta-coated Ti alloy implants with wide clinical applications
[en] The effects of gasoline and ethanol addition on the spray and atomization characteristics of diesel spray from a common rail injection system, was investigated in a constant volume chamber at different ambient and injection pressures. The fuel spray evolution process was recorded with high spatial and time resolution and the corresponding spray tip penetration (STP), the cone angle were extracted. The results show that increased gasoline proportion in the test blends causes decreased STP and increased spray cone angle. Additionally, the microscopic spray characteristics such as the local average droplet diameter and statistical size distributions were measured by particle/droplet image analysis (PDIA) technique. As gasoline blending ratio increases, significantly smaller droplet size was observed which indicates that the spray breakup and atomization processes were promoted. Further adding ethanol slightly increased the droplet size, but it is still much smaller than the droplet size of neat diesel spray. Moreover, the local droplet size increases along the radial direction but the local droplet volume fraction and normalized droplet number density decreases, indicating a reduced fuel concentration along the radial direction. Along the axial direction, the droplet size, the local droplet volume fraction and the normalized droplet number density were almost constant. - Highlights: • The increased gasoline fraction in diesel/gasoline blends leads to decreased spray tip penetration. • Gasoline blending significantly reduces the average droplet size while further addition of ethanol slightly decreases the droplet size. • Along the radial direction the droplet size increases, but the number density decreases.
[en] Recently, Pani et al. explored a new theory of gravity by adding nondynamical fields, i.e., gravity with auxiliary fields (Phys Rev D 88:121502, 2013). In this gravity theory, higher-order derivatives of matter fields generically appear in the field equations. In this paper we extend this theory to any dimensions and discuss the thick braneworld model in five dimensions. Domain wall solutions are obtained numerically. The stability of the brane system under tensor perturbations is analyzed. We find that the system is stable under tensor perturbations and the gravity zero mode is localized on the brane. Therefore, the four-dimensional Newtonian potential can be realized on the brane. (orig.)
[en] A new theory of gravity called Eddington-inspired Born-Infeld (EiBI) gravity was recently proposed by Banados and Ferreira. This theory leads to some exciting new features, such as free of cosmological singularities. In this paper, we first obtain a charged EiBI black hole solution with a nonvanishing cosmological constant when the electromagnetic field is included in. Then based on it, we study the strong gravitational lensing by the asymptotic flat charged EiBI black hole. The strong deflection limit coefficients and observables are shown to closely depend on the additional coupling parameter κ in the EiBI gravity. It is found that, compared with the corresponding charged black hole in general relativity, the positive coupling parameter κ will shrink the black hole horizon and photon sphere. Moreover, the coupling parameter will decrease the angular position and relative magnitudes of the relativistic images, while increase the angular separation, which may shine new light on testing such gravity theory in near future by the astronomical instruments. (orig.)
[en] One of the main hurdles for nanometer focusing by a bending mirror lies in the theoretical surface errors by its approximations used for the traditional theory. The impacts of approximations and analytical corrections have been discussed, and the elliptically bent mirror theory has been described during exact mathematical analysis without any approximations. These approximations are harmful for the focusing system with bigger grazing angle, bigger mirror length, and bigger numerical aperture. The properties of equal-moment and single-moment bent mirrors have been described and discussed. Because of its obvious advantages, a single-moment bending mirror has high potential ability for nanometer focusing.
[en] Hydrogen storage materials have been used for the storage, purification, compress of tritium and the separation of hydrogen isotopes. The research progress in this field and the excellence of their applications in tritium technics as well as the characteristics of some typical hydrogen storage materials are introduced in brief. (authors)
[en] The author describes control rod drive mechanism (CRDM) principle sample air cooling and heat ejection test for Qinshan Phase II 600 MW nuclear power plants (NPP) . By simulating the real operating condition of reactor, the CRDM air flow pressure drop in cooling channel, allowed minimum air cooling speed and the relationship between heat ejection and air cooling speed are determined. Also, the requirements of CRDM operation are got by the test
[en] With the new physical interpretation of quasinormal modes proposed by Maggiore, the quantum area spectra of black holes have been investigated recently. Adopting the modified Hod's treatment, results show that the area spectra for black holes are equally spaced and the spacings are in a unified form, A=8π(ℎ/2π), in Einstein gravity. On the other hand, following Kunstatter's method, the studies show that the area spectrum for a nonrotating black hole with no charge is equidistant. And for a rotating (or charged) black hole, it is also equidistant and independent of the angular momentum J (or charge q) when the black hole is far from the extremal case. In this paper, we mainly deal with the area spectrum of the stringy charged Garfinkle-Horowitz-Strominger black hole, originating from the effective action that emerges in low-energy string theory. We find that both methods give the same results--that the area spectrum is equally spaced and does not depend on the charge q. Our study may provide new insights into understanding the area spectrum and entropy spectrum for stringy black holes.