Measurements of distribution of self-bias potential on an RF-plane electrode in plasma etching devices

The self-bias potential (V_dc) induced on an RF-powdered electrode (153 mm Ø) in a plasma is measured using electrical probes which are buried in, de-insulated from, and RF-connected to the electrode. The configuration of the probes allows to study the distribution of V_dc discretely on the electrode. The potential is homogeneous in the absence of external magnetic field. In the presence of a homogeneous magnetic field parallel to the electrode, it is reduced and a monotonous gradient takes place in its distribution due to the plasma shift induced by E × B drift. When the magnetic field is rotated along the axis of the RF-electrode at a frequency less than 50 Hz, the distribution, which is almost identical to the one in a static field, rotates with the magnetic field. On the coordinate system rotating with the magnetic field, the probes are regarded to be rotating. The potential distribution is obtained as a continuous function of the azimuthal angle. Thus the rotation of the field provides information for the experimental interpolation.     

Morphology of thin anatase coatings prepared from alkoxide solutions containing organic polymer,affecting the photocatalytic decomposition of aqueous acetic acid

Porous anatase coatings were prepared from alkoxide solutions containing organic polymer by a dip-coating technique. The morphology of the coatings, such as pore size, pore distribution and thickness, was controlled. The effects of the morphology of the porous anatase coatings on the photocatalytic activity for the photocatalytic decomposition of aqueous acetic acid were examined.     

Preparation and photoconduction of rapidly quenched films in the Bi2O31bM2O5 system (M=V,Nb and Ta)

The Bi₂O₃1bM₂O₅ films (M=V, Nb and Ta) were prepared by a rapid quenching technique using a twin-roller type equipment. Quenched film of pure Bi₂O₃ partially precipitated a tetragonal phase which differs from well-known β-Bi₂O₃ in structure. In every (Bi₂O₃)_0.975 (M₂O₅)_0.025 composition (2.5% M₂O₅), the tetragonal phase was obtained as single phase, and the tetragonality became greater than that of the pure Bi₂O₃. Beyond this composition, the tetragonality decreased to form δ-phase with a fcc structure with increasing the M₂O₅ content. The lowest V₂O₅ content forming a δ-phase was 5%, while a slight tetragonality still remained in the samples containing 10% Nb₂O₅ and 10% Ta₂O₅, respectively. From the measurement of the photoconductivities of the quenched films, it was proved that a photoconduction appeared in the tetragonal phase while no photoconductivity was observed in the cubic phase. The characteristic of the photoconduction was that a remarkable decrease in the resistivity was observed when a light of ca. 500 nm in wave length was irradiated on the films.     

Hydroliquefaction of low-sulfur coals using iron carbonyl complexes—Sulfur as catalysts

Hydroliquefaction of low-sulfur Australian coals (Wandoan and Yallourn) was studied using iron carbonyl complexes as catalyst. The addition of Fe(CO)₅ (2.8 wt% Fe of coal) increased coal conversion from 48.6 to 85.2% for Wandoan coal, and from 36.7 to 69.7% for Yallourn coal in 1-methylnaphthalene at 425°C under an initial hydrogen pressure of 50 kg cm^?2. When molecular sulfur was added to iron carbonyls (Fe(CO)₅, Fe₂(CO)₉ and Fe₃(CO)₁₂), higher coal converions ( > 92%) and higher oil yields (>46%) were obtained, along with an increase in the amount of hydrogen transferred to coal from the gas phase (0.2 to 2.8%, d.a.f. coal basis). In the liquefaction studies using a hydrogen donor solvent, tetralin, Fe(CO)₅S catalyst increased the amount of hydrogen absorbed from the gaseous phase and decreased the amount of naphthalene dehydrogenated from tetralin. The direct hydrogen transfer reaction from molecular hydrogen to coal fragment radicals seems to be a major reaction pathway. Organic sulfur compounds, dimethyldisulfide and benzothiophene, and inorganic FeS₂ and NiS were found to be good sulfur sources to Fe(CO)₅. From X-ray diffraction analyses of liquefaction residues, it is concluded that Fe(CO)₅ was converted into pyrrhotite (Fe_1?xS) when sulfur was present, but into Fe₃O₄ in the absence of sulfur.     

Precise rendering method for exact anti-aliasing and highlighting

This paper introduces the Precise Rendering Method, which generates accurately anti-aliased and highlighted images from tessellated polygons. The Precise Rendering Method first solves the aliasing problems of hidden surface removal by using the Cross Scanline Algorithm. This algorithm can exactly calculate polygon areas projected onto each pixel by using horizontal and vertical scanlines. Aliasing artifacts in shading are then prevented by the Reflection Intergration Method, which analytically integrates the intensity of reflection in the solid angle defined by surface normals at vertices of the projected area. Several synthesized images are created to show the efficiency of the Precise Rendering Method.     

A dynamic Houjin (square) and a symmetric Houjin

A Houjin is an n by n square lattice with each cell containing a symbol (such as a number or a letter). Further, these numbers or letters are designed to exhibit symmetry. For example, a magic square is a Houjin where the embedded symmetry is that the numbers in each row, column, and a center diagonal have an equal sum. This article reports a new Houjin: a dynamic Houjin. A dynamic Houjin changes its numbers at each time step while satisfying the symmetry as a Houjin (a magic square). The dynamic Houjin has a further symmetry in a time dimension, i.e., the sums of the numbers in each cell are identical.     

Preparation of zinc ferrite in the presence of carbon material and its application to hot-gas cleaning

In order to develop an efficient absorbent of H₂S in coal gasification, zinc ferrite (ZnFe₂O₄) was prepared in the presence of carbon materials such as activated carbon (AC), activated carbon fiber (ACF), and Yallourn coal (YL). The absorption behavior of absorbents for H₂S was examined using a fixed-bed flow type reactor equipped with a quadrupole mass spectrometer.Carbon material-supported ZnFe₂O₄ exhibited larger desulfurization capacity for H₂S than unsupported ferrites. They could efficiently remove H₂S from 4000 ppm levels in a simulated coal gasification gas to less than 1 ppm at 500 °C. The absorption capacity of H₂S with ZnFe₂O₄/AC, ZnFe₂O₄/ACF, and ZnFe₂O₄/YL exhibited nearly 100% of stoichiometric amount of loaded metal species. They could be regenerated by an air oxidation in O₂-Ar (50 vol%) at 450 °C for 30 min. The regenerated ferrite can be used for repeated absorption of H₂S with a very slight decrease in the absorption capacity.