Satoshi Itoh

Experimental Observation of a Possible First-Order Phase Transition below the Superconducting Transition Temperature in the Multilayer Cuprate Superconductor HgBa2Ca4Cu5Oy

A hysteretic specific heat jump at approximately 41 K is found experimentally in the multilayer cuprate superconductor HgBa2Ca4Cu5Oy (Hg-1245), with a superconducting transition temperature of 108 ...

Self-Consistent Numerical-Basis-Set LCAO Method Based on the Norm-Conserving Pseudopotential

A new procedure is presented for the self-consistent calculation of the electronic structure of a large-sized cluster with a low-symmetry. This is based on the numerical-basis-set LCAO method and the norm-conserving pseudopotential, and contains no adjustable parameters. Owing to such contrivances, we can calculate the electronic structure of the large-sized cluster with a small number of basis functions per atom. The electronic structure of monoclinic selenium is calculated by using this method, and we obtain a good agreement between calculated and observed properties such as cohesive energy and equilibrium bond length, without a huge computational time.

Electronic Structure of Structural Defects in Sulfur

The electronic structure of the structural defects in sulfur is investigated on the self-consistent numerical-basis-set LCAO method. The ground states of the isolated one-fold and three-fold coordinated defects are shown to be always neutral, and it is also shown that the isolated one-fold coordinated defect is more stable than the three-fold coordinated one, in contrast to the customary qualitative model for these defects. Furthermore, the characteristic defect states are found to appear in the band gap. Based on these results, the electronic state of the complex defect is also discussed briefly.

Toroidal Theta Pinch Collapse by the Snowplow Model

Accurate equations for the cross section of the toroidal theta pinched plasma column are derived using the snowplow model, and then are solved numerically to study the shift of the column position and the deformation of the cross section during the collapse. The column shifts towards the outer wall and the shape of the cross section changes from the initial circle into a heart as the collapse proceeds. The shift and the deformation, however, are not serious, if the aspect ratio is larger than 10.

Modes of the Screw Instability in a Positive Column with Longitudinal Magnetic Field

The modes of screw instability in a positive column of a nitrogen gas discharge have been studied. Under a certain condition, the critical magnetic field for the m=2 mode has been found to be smaller than that for the m=1 mode. In addition, the regular oscillations have been observed at the magnetic field larger than the critical one. These phenomena can not be described by the results of Kadomtsev and Nedospasov which are calculated from the small‐amplitude theory. In this paper a theoretical explanation for these phenomena is proposed based on the conception that only the instability which has the maximum growth rate can grow while other instabilities are masked.

RADIAL DENSITY PROFILE IN A POSITIVE COLUMN WITH A LONGITUDINAL MAGNETIC FIELD.

The radial density profile is investigated experimentally and compared with the theoretical results of Holter and Johnson. The experimental results agree qualitatively with the theoretical ones under some experimental conditions.

Electronic Structure of VAP in Sulfur

The electronic structure of the valence alternation pair (VAP; one of the complex structural defects with a charge transfer) in sulfur has been investigated self-consistently by using the cluster with a simple structure. It is found that the one-fold coordinated atom in the VAP is positively charged and the three-fold coordinated one is negatively charged. Moreover, the VAP is expected to be more stable than the non-interacting pair of the isolated one-fold coordinated and three-fold coordinated defects. It is also shown that there is no half-filled defect level associated with the VAP. The present theoretical result is consistent with the experimental one.

Passage of a Small Sphere through a Cleft of Endothelia with Pivoted Glycocalyx

The motion of a small sphere in a viscous fluid toward a cleft of the endothelia covered with glycocalyx bush is analyzed on the basis of the Stokes equation. Endothelia are approximated by a packed hexagonal planar arrangement of beads of equal radius, from which one of the bead is removed form a cleft. The chains representing units of the glycocalyx bush are also approximated by columns of beads. In the present model, the glyco-chain is allowed to pivot on the “foot” of the chain, i.e., the bead attached to the endothelial bead, whose orientation is determined by the hydrodynamic forces and moments associated with the motion of the sphere and the chains. Dependences of the motion of the sphere on the length and easiness to pivot the glyco-chains, are analyzed. We have found that the more easiness to pivot the glyco-chain we put, the larger effect the magnitude of the spheres velocity experiences. Effect of the size of the sphere on the passage is also examined.

Plasma development of SR irradiated plasma polymerized resists

Synchrotron radiation (SR) vacuum lithography was carried out using plasma chemical processes. Plasma-polymerized and -copolymerized polymethyl methacrylate (PMMA) resists were irradiated by SR directly, and the film thickness was reduced due to the random decomposition of the polymer. Self-development was enhanced by incorporation of Sn, S, F and I as sensitizers into plasma-polymerized while it was restrained by incorporation of styrene. The thickness reduction was completely saturated at a high dose for all plasma-polymerized resists. Oxygen plasma etching enhanced the positive tone pattern on the resist following SR irradiation doses below the saturation level. Surface treatment of plasma-polymerized FBM using W(CO)/sub 6/ as a monomer gas was also found to enhance differential thickness.<<ETX>>

X Ray Mask Of Gold-Carbon Mixture Absorber On BCN Compound Substrate Fabricated By Plasma Processes

X-ray mask fabrication based on BCN compound membrane and gold containing polymeric carbon ( Au-C ) absorber by totally dry processes is proposed. The Au-C films were depo-sited by plasma polymerization of propylene or styrene monomers and co-evaporation of gold. These films have 2 to 5 times higher etching rate than that of pure gold for 09 RIE, depending on the Au content. The stress in the films could be reduced to 1.9 E 7 N/m2 by annealing. The BCN films were deposited on silicon wafers by rf (13.56 MHz) plasma CVD with diborane, methane and nitrogen as source gases at typical deposition rate of 30 nm/min. The optical (633nm) and X ray (Pd L∝) transparencies were nearly 80% for film thickness of 6 um. Patterning of Au-C was achieved by using tungsten as intermediate layer and PMMA electron beam resist. CF4 RIE was used to etch the tungsten layer which in turn acted as mask for the gold carbide 02 RIE. The process parameters and the characteristics of the Au-C and BCN films are presented.