[en] H13 steel samples were implanted with tungsten and the improvement in surface mechanical properties was investigated. The tungsten ion implantation was done using a metal vapor vacuum arc (MEVVA) ion source, with an ion current density of 15 μA cm^-2. The implantation of tungsten showed a superior wear resistance surface. The relationship between surface mechanical property and microstructure for the tungsten-implanted samples was characterized by Rutherford backscattering spectroscopy (RBS), grazing-angle X-ray diffraction (GAXRD) and X-ray photoelectron spectroscopy (XPS). The tungsten carbides and tungsten oxides were observed in the doped region. The experimental results have shown that the formation of WC and WO₃ improved the wear resistance of H13 steel

[en] The tribological properties of Ta-implanted H13 steel was studied using a metal vapor vacuum arc (MEVVA) ion source. The doses of Ta and C ions implanted on H13 steel were 5x10¹⁷ and 2x10¹⁷ cm^-2, respectively. The extraction voltages were 48 kV for Ta implantation and 30 kV for C implantation. Rutherford backscattering spectrum (RBS) was used to measure the surface composition of the samples implanted. The observation of phase induced by Ta, C implantation was carried out by grazing-angle X-ray diffraction (GXRD). The wear test of the implanted surface revealed that Ta+C dual implantation reduced the wear of the implanted steel by nearly a factor of 2. This wear mechanism of the Ta-implanted steel was compared with that of Ti implantation

No abstract available

[en] The Si-TiO_2 based composites with a nanosized multi-sphere structure have been developed as novel anode for lithium ion cells. The Si spheres are highly embedded within the titanium dioxide nanoparticles via a hydrothermal synthesis route. The as-proposed sphere-stack like morphology achieves a superior cycling stability for lithium storage. The existence of TiO_2 is in favor for the mechanical stability of Si during charge-discharge and conversely reduces the obtained capacity of the composite. Furthermore, the Si/TiO_2 composite is coated by pyrolysized carbon. The reversible discharge capacity of the Si/TiO_2/C composite reaches to 976 mAh g"−"1after 50 cycles. Carbon coating is beneficial for the rate capability of the Si/TiO_2 based composite.

[en] The lower hybrid current drive experiment has been performed on the HT-7 tokamak. The wave power varied from 100 kW to 700 kW with a frequency of 2.45 GHz. The relation between the power of lower hybrid wave and the average effective charge number and electron temperature was studied. It is shown that the current drive efficiency is proportional to the electron temperature, and inversely proportional to the effective charge number. The dynamic control of the impurity of plasma is a key to improve the current drive efficiency. (authors)

[en] A new algorithm is introduced to reconstruct the parameters of plasma from line-integral data. This method is based on the Radon inversion theory. The series expansion and least-square methods are employed to get the Radon inversion of the plasma parameter on the minor cross-section of tokamak. Then the plasma parameter can be given by the Radon inversion formula. This algorithm is introduced to study the asymmetric phenomenon between the positive and negative current plasma of the X-ray emission in HT-7 tokamak. (authors)

[en] A compact hydrogen plasma gun system was designed and tested. There are two rings of graphite and two rings of Ti hydride between coaxial electrodes. Ti hydride is utilized as a reservoir of hydrogen. The surface flashover is taken advantage to produce plasma. The produced plasma density is 10¹⁰ cm^-3-10¹² cm^-3 in a volume of a column with radius 1-2 cm and length of 60-80 cm. The plasma existing time is over 400 μs

[en] We investigate a multi-frequency signal that cannot be decomposed by empirical mode decomposition directly. Moreover, this kind of signal in the noisy background cannot be decomposed successfully by the traditional stochastic resonance with bistable system yet. We propose a new method which using the empirical mode decomposition combined the adaptive stochastic resonance in a new periodical model to solve this problem. The results show that the proposed method decomposes the multi-frequency signal perfectly. Meanwhile, the general scale transformation and random particle swarm optimization algorithm are used to help obtain a better result in the process of optimization. Through using this new method, the simulation results are satisfactory. More importantly, this new method also shows good performance in the application of bearing fault diagnosis.

[en] With the continuous improvement of people’s living standard, the consumption of electricity also increased, which requires a larger capacity of the conductor for electricity transmission. Therefore, comprehensive selection of conductor type made higher requirements. Based on the analysis, this paper divides the basic indication of conductor selection into two types: cost type and efficiency type, then each category is divided into a number of specific indicators based on needs, finally, using the grey relational analysis method to compare and analyze the cost indication and efficiency indication of conductors, which draws the optimization scheme of conductor selection, and is used to guide the type selection of conductor type. (paper)

[en] Using external longitudinal magnetic-field to guide dual-beam out of the dual-shift tubes is a key step for the practicality of synchronizing dual-beam produced by a single accelerator. On the basis of the simulation of the confining magnetic-field for the solid dual-beam, the experiment of magnetic-field guiding annular dual-beam was presented. When the diode voltage was 380 kV, dual-beam currents of 5.10 kA and 4.92 kA were obtained. The experimental results indicate that the designed magnetic-field system could confine the annular dual-beam effectively, and the critical confining magnetic-field is about 0.5 T. (authors)