[en] Several techniques such as stereopair diffraction, topo-tomography have been used previously to determine the direction of three-dimensional defects in crystals using monochromic radiation. A new method is proposed here to calculate the orientation of dislocations using white synchrotron radiation, simple and convenient to utilize

[en] We have investigated the fabrication and computational modelling of three-dimensional phononic crystals for the observation of full band gaps for thermal phonons at sub-kelvin temperatures. Self-assembled arrays of monodisperse polystyrene nano-spheres have been fabricated using a vertical deposition technique. Optimal conditions for increasing crystal domain size and crystalline quality have been studied. In addition, the phononic band structure has been computed using the finite element method for the simple cubic lattice. The dependence of band structure on contact area between spheres has also been studied. For small enough contact area a large band gap is observed, predicting a strong influence on sub-Kelvin thermal transport.

[en] Carbon nanotubes (CNs) have a wide variety of important properties and many potential applications. There are mainly two methods to prepare CNs, one of them is the arc-discharge evaporation, the other is the catalytic decomposition of hydrocarbon. Here we report the preparation of CNs by nickel catalyzed decomposition of methane at 873 K. The CNs formed have the length of several micron, their outer diameters are 30-12 nm, and the inner ones 10-8 nm. The reduction temperature of the nickel catalyst used has significant effect on the amount of CNs formed. It is possible to prepare CNs on a large scale under the relatively mild conditions by the catalytic method.

[en] In order to match directly the beams from the gas-filled recoil separator, a RFQ cooler and buncher RFQ1L has been designed to have a large radius (r₀=60 mm), thus the RF power supply becomes not a trivial problem. We have successfully solved this problem by two different methods, and the RF power supplies specific to the RFQ1L have been developed and tested. Technical descriptions and test results are presented in this paper. It shows that the power supply with series resonance circuits should be used for the operation of the RFQ1L.

[en] The SHANS spectrometer is under construction in the Institute of Modern Physics, Chinese Academy of Science. The RFQ cooler and buncher RFQ1L is one of the key devices in the SHANS. To perform direct mass measurement, the Lanzhou Penning Trap LPT is also under construction. In this symposium, the principle of the SHANS, the status of RFQ1L and LPT and some primary test results will be reported.

[en] This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges

[en] Ultra-fast high-temperature microwave annealing at temperatures as high as 2050 deg. C for 30 s has been performed on phosphorus ion-implanted 4H-SiC for phosphorus doping concentrations in the range 5x10¹⁹ cm^-3-8x10²⁰ cm^-3. For comparison, inductive heating furnace anneals were performed at 1800 deg. C-1950 deg. C for 5 min. Electrical resistivity of the P⁺-implanted samples decreased with increasing annealing temperature reaching a minimum value of 6.8x10^-4 Ωcm for 2050 deg. C/30 s microwave annealing and a slightly higher value for 1950 deg. C/5 min inductive heating furnace annealing. X-ray rocking curve measurements showed that the microwave annealing not only removed the lattice damage introduced by the ion-implantation process, but also the defects present in the original virgin sample as well.

[en] The fabrication of a fully ion-implanted vertical p–i–n diode using high-purity semi-insulating 4H–SiC substrate has been demonstrated for the first time. The intrinsic region is the wafer itself with a thickness of 350 µm. The anode and cathode are obtained by doping the front and back wafer surfaces with implanted Al⁺ and P⁺ ions, respectively, with concentrations of about 10²⁰ cm⁻³. The electrical activation of the implanted dopants is obtained by microwave heating the samples up to 2100 °C for 30 s. At ±100 V the on and off state current ratio is in the order of 10⁴. Forward saturation current is five orders larger than it would be if controlled by the series resistance of the thick HPSI 4H–SiC intrinsic region. (paper)