Photocatalytic Property and Electronic Structure of Lanthanide-based Oxysulfides

Lanthanide-based oxysulfides and sulfide, LnTaO_3.5S_0.5, Ln₁₀OS₁₄ (Ln = La, Pr, Nd, Sm) and La₄In₅S₁₃, were successively synthesized by sulfurization in a flowing H₂S. The sulfurization decreased the band-gap energies from >4 eV to <3eV, because of the formation of occupied S3p orbitals on the top of valence band. In accordance with the small band gap, the H₂ evolution from a 0.01 M Na₂S and 0.01 M Na₂SO₃ solution system was observed under irradiation of light up to >500 nm. The rate of H₂ evolution under light irradiation of >500 nm increased in the order of Ni/LaTaO_3.5S_0.5 < Ru/La₁₀OS₁₄ < Pt/La₄In₅S₁₃.     

Development of 170 GHz/500 kW gyrotron

A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER. The oscillation mode is TE_31,8. In a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A. The efficiency was 22%. In the depressed collector operation, 500kW/36%/50ms was obtained. The maximum efficiency of 40% was obtained at P_RF=470kW whereas the power decrease by the electron trapping was observed. Pulse extension was done up to 10s at P_RF=170kW with the depressed collector operation. The power was limited by the temperature increase of the output window.     

Preparation and mesostructure control of highly ordered zirconia particles having crystalline walls

Mesostructured zirconia particles having monoclinic-type crystalline walls were prepared using a low-temperature crystallization technique. Crystalline zirconia particles with highly-ordered mesostructures were obtained through the sol–gel process of zirconium sulfate tetrahydrate at 333 K in the presence of molecular self-assemblies of cetyltrimethylammonium bromide (CTAB) or mixtures of CTAB and anionic molecules such as sodium dodecyl sulfate and sodium p-toluenesulfonate. Variations in the molar ratios of CTAB and the chemical species of anionic molecules led to the variations in the periods of highly-ordered zirconia having crystalline walls. Calcination of the mesostructured zirconia particles prepared using templates consisting solely of CTAB yielded crystalline mesoporous zirconia particles.     

Effect of Ultrasonication on the Microstructure and Tensile Elongation of Zirconia-Dispersed Alumina Ceramics Prepared by Colloidal Processing

To obtain dense, fine-grained ceramics, fine particles and advanced powder processing, such as colloidal processing, are needed. Al₂O₃ and ZrO₂ particles are dispersed in colloidal suspensions by electrosteric repulsion because of polyelectrolyte absorbed on their surfaces. However, additional redispersion treatment such as ultrasonication is required to obtain dispersed suspensions because fine particles tend to agglomerate. The results demonstrate that ultrasonication is effective in improving particle dispersion in suspensions and producing a homogeneous fine microstructure of sintered materials. Superplastic tensile ductility is improved by ultrasonication in preparing suspensions because of the dense and homogeneous fine microstructure.     

An Effective Cache Replacement Algorithm in Transcoding-Enabled Proxies

In this paper, we address the problem of cache replacement for transcoding proxy caching. Transcoding proxy is a proxy that has the functionality of transcoding a multimedia object into an appropriate format or resolution for each client. We first propose an effective cache replacement algorithm for transcoding proxy. In general, when a new object is to be cached, cache replacement algorithms evict some of the cached objects with the least profit to accommodate the new object. Our algorithm takes into account of the inter-relationships among different versions of the same multimedia object, and selects the versions to replace according to their aggregate profit which usually differs from simple summation of their individual profits as assumed in the existing algorithms. It also considers cache consistency, which is not considered in the existing algorithms. We then present a complexity analysis to show the efficiency of our algorithm. Finally, we give extensive simulation results to compare the performance of our algorithm with some existing algorithms. The results show that our algorithm outperforms others in terms of various performance metrics.     

Analog CMOS circuit design and characterization for optical coherence tomography signal processing

We have developed a custom analog CMOS circuit to perform the signal processing for an optical coherence tomography imaging system. The circuit is realized in a 1.5 /spl mu/m low-noise analog CMOS technology. The circuitry extracts the Doppler frequency from the signal and electrically mixes this with the original signal to provide a filtered A-scan. The circuitry was used to produce a two-dimensional image of an onion.     

Determination of standard gibbs energies of formation of Cr2N and CrN

The standard Gibbs energies of formation of Cr₂N and CrN have been measured by an equilibration technique and by using thermogravimetry and differential thermal analysis (TG-DTA) at temperatures ranging from 1232 to 1523 K. The results are expressed as follows:

ALIS method for high‐resolution color PDPs

This paper describes the Alternate Lighting of Surfaces (ALIS) method as a promising drive technology which can lead to high‐resolution plasma‐display panels (PDPs). This technology provides a resolution of more than 1000 scanning lines without lowering luminance, thus enabling the essential requirements of HDTV. Moreover, it allows the number of scanning electrodes to be halved in comparison with the conventional method, as well as the circuit scale to be minimized due to the use of the single scanning drive. The ALIS method is expected to be a key technology that will help PDPs penetrate the TV market.     

Measurement of RF Transmission Mode in ITER Relevant EC H&;CD Transmission Line

The preliminary results of mode measurement in the ITER relevant 40 m long transmission test line composed from 63.5 mm diameter corrugated waveguides and miter bends are presented. The field patterns were measured by taking temperature profiles on a paper screen placed in front of the waveguide end using an infrared imaging camera. The complex electric field at the waveguide end was retrieved from the measured temperature profiles. As a result, the transmission power includes 87% of HE₁₁ mode and 6% of LP₁₁ odd (HE₂₁+TE₀₁) mode and small ratios of other modes. The mode content had small dependence on length of the transmission line. This result indicated that the higher order mode content generated at the input of the transmission line is conserved and propagated through the transmission line. This suggests that the initial RF coupling to the waveguide is critical since it affects the launcher efficiency.