[en] During the Spacelab 2 mission the University of Iowa's Plasma Diagnostics Package (PDP) explored the plasma environment around the shuttle. Wideband spectrograms of plasma waves were obtained from the PDP at frequencies from 0 to 30 kHz up to 400 m from the shuttle. These spectrograms frequently showed interference patterns caused by waves with wavelengths short compared to the antenna length (3.89 meters). Two types of interference patterns were observed in the wideband data: associated with the ejection of an electron beam from the space shuttle; associated with lower hybrid waves generated by an interaction between the neutral gas cloud around shuttle and the ambient ionospheric plasma. Analysis of these antenna interference patterns permits a determination of the wavelength, the plasma rest frame frequency, the direction of propagation, the power spectrum and in some cases the location of the source. The electric field noise associated with the electron beam was observed in the wideband data for two periods during which an electron frequency range at low frequencies (below 10 kHz) and shows clear evidence of interference patterns. The broadband low frequency noise was the dominant type of noise produced by the electron beam. The waves have a linear dispersion relation very similar to ion acoustic waves. The returning to the shuttle in response to the ejected electron beam. The waves associated with the lower hybrid resonance have rest frame frequencies near the lower hybrid frequency and propagate perpendicular to the magnetic field. The occurrence of these waves depends strongly on the PDP's position relative to the shuttle and the magnetic field direction. The authors results confirm previous identifications of these waves as lower hybrid waves and suggest they are driven by pick-up ions (H₂O⁺) produced by a charge exchange interaction between a water cloud around the shuttle and the ambient ionosphere

[en] Current self-oscillation in doped n⁺nn⁺ wurtzite InN diodes driven by a dc electric field is theoretically investigated by solving the time-dependent drift-diffusion model. Current self-oscillation is associated with the negative differential mobility effect in the highly non-parabolic conduction band of InN. A detailed analysis of the dependence of current oscillations on the doping concentration and the applied electric field is presented. The current oscillation frequencies can reach up to the terahertz (THz) region. The n+nn+ InN self-oscillating diode may be a promising candidate for THz generation, and the calculation results may guide the design of the devices. (authors)

[en] Data centers must be cooled appropriately through indoor temperature control in order to improve information technology (IT) equipment reliability. Free cooling is a promising technology for energy conservation in data centers. A miniature pump-driven loop heat pipe (PLHP) unit for free cooling is developed for a small data center. The unit consumes low power and has a high energy efficiency ratio (EER) compared with air conditioners. The operating performance of the PLHP unit installed in the case data center in Beijing was tested and studied. The EERs under different outdoor temperatures were analyzed, and the fitting variation rules were obtained. Compared with air conditioners, the annual energy savings of the PLHP unit for both hours and days were tested and analyzed based on the fitting formula. Results show that indoor temperature is maintained at 18–25 °C, and that the test energy saving ratio is over 20.18%. Hence, the PLHP unit can replace air conditioners for cooling the case data center.

[en] The author introduces the Pulse Parameter Measurement System of Xi'an Pulsed Reactor. It is the only nuclear instrument, which measures the reactor power, and undertake protection task during pulsing operation condition. The device applies advanced and sophisticated microelectronics and computer technology, so that it can real-timely measure and display reactor power change, pulse waveform and a lot of parameters automatically during pulsing operation condition. Once the power goes up beyond threshold, it will send emergent trip and alarm signal to reactor protection system and alarm system. The work performance of the device is introduced. Application of the device is described as well

[en] The only reasonable mechanism by which radionuclide can be brought from a repository to biosphere is through migration in barrier materials under the movement of groundwater. Through great amount of experiments, it has been proved that the diffusion of radionuclides in geologic media obeys Fick Second Law. This paper gives the analytic solution of the radionuclide migration equation by the Laplace transformation. Thus we can predict the migration of radionuclides in certain medium conveniently

[en] The northeast margin of Qaidamu Basin is situated in the east of endogenied mineral zone. Based on characteristic of regional geology, structural evolution as well as uranium mineralization, uranium metallogenic condition of structure-magma evolution is analyzed. The uranium construct includes the Paleo Proterozoic Dakendaban group, Ordovician-Silurian Tanjianshan group and the upper Devonian Maoniushan group. The space distribution of stratum, magmatic rock and uranium mineralization is controlled by Magmatic activity of Caledonian, Variscan and Indo-Chinese epoch, NW fault belts. We consider that the uranium mineralization is a trinity including uranium containing structure, faulted belt and intermediate-acid magmatic activities. Moreover, the exploration prospect of uranium mineralization is also discussed in this study. (authors)

[en] The domestic DCS Simulation System of Fuqing Nuclear Power Plant's Second Full scope simulator applied several technologies which result in shorter project period, decreased workload as well as high precision. The paper introduces the implementation details of these technologies and compares the function and performance with the first Simulator to prove that domestic DCS Simulation system can replace the imported one and have its own advantages. The use of new technologies may Cause problems which are also considered in this paper for further improvement of Chinese nuclear power plant simulator. (authors)

[en] Hydrodynamic calculations of the chaotic behaviors in n⁺nn⁺ In_0.53Ga_0.47As devices biased in terahertz (THz) electric field have been carried out. Their different transport characteristics have been carefully investigated by tuning the n-region parameters and the applied ac radiation. The oscillatory mode is found to transit between synchronization and chaos, as verified by the first return map. The transitions result from the mixture of the dc induced oscillation and the one driven by the ac radiation. Our findings will give further and thorough understanding of electron transport in In_0.53Ga_0.47As terahertz oscillator, which is a promising solid-state THz source. (special topic)

[en] 7 series high strength aluminum alloy under high temperature and without protective easy to rust, now 7 series for high strength aluminum alloy work piece is dried after rinsing water way, compressed air after water hot air drying cutting surface, the drying after the work piece can meet the requirements of the assembly of the late, but also in the dry mass artifacts appear many instability, the main reason is that aluminium alloy work piece for a long time at high temperature, high oxygen environment. In order to solve the problem of high temperature and high oxygen, the vacuum drying process was developed for experimental verification. The vacuum drying process was optimized through the experiment, and the surface and inner cleanness of the blind hole of the work piece after vacuum drying and hot air drying were compared. The stability of the vacuum drying process was verified by batch test. (authors)

[en] Using Moessbauer spectroscopy, the authors have studied the structural characteristics of the alloy phases of three samples formed by the process of mechanical alloying. The starting compositions of these samples are Fe₇₀B₃₀, Fe₅₅B₄₅ and Fe₃₀B₇₀. The crystallization or transition of the amorphous phases under annealing has also been examined. It was found that a certain relation exist between the amorphous phases and corresponding Fe-B compounds