Optical emission spectroscopic study for diagnostics in high gravity DC-plasma CVD diamond growth

The effect of gravity on materials processing is rather complicated, and a large number of considerably unexpected results due to high gravity or sometimes centrifugation have been reported. The authors have been conducting high gravity diamond thin film growth by the DC-plasma CVD method up to 100 G. The effects of high gravity appeared in the nucleation site density, growth rate, grain size, uniformity, film coverage and morphology. With the increase in gravity, the nucleation site density, growth rate, grain size were all found to be increased, the uniformity and film coverage were improved, and {100} facet became dominant rather than {111} facet. To understand the deposition mechanism in these effects observed in high gravity, a diagnostic apparatus for spectroscopic study of the optical emission from the DC-plasma was developed, and the OES (optical emission spectroscopy) apparatus has been employed in high gravity CVD experiments. The influence of gravity on the most active species in the plasma, such as H, CH, C₂ was discussed together with the results from the Raman spectroscopy and X-ray diffraction study.     

An e.s.r. study of the motion of peroxy radicals in isotactic and atactic polypropylenes

E.s.r. spectra of peroxy radicals trapped in isotactic and atactic polypropylenes have been observed at various temperatures. The spectrum observed at 77 K was shown to be composed of one component by comparing it with that at 4 K. The spectra observed at higher temperatures comprised of two spectra arising from the rigid peroxy radicals and the mobile peroxy radicals. All of the observed spectra have been reconstructed by means of computer simulation and the changes in anisotropic g-values with temperature were estimated. The motion of the mobile fraction was shown to be rotation or rotatory vibration of the radicals around the chain axis both in the isotactic polypropylene and in the atactic polypropylene as well as in polyethylene and poly(tetrafluoroethylene) although the structures of the polymers are different, that is helical (polypropylene) or planar zigzag (polyethylene, poly(tetrafluoroethylene)).     

Novel method for site-controlled surface nanodot fabrication by ion beam synthesis

By using a Ga FIB system to spatially control the implantation of Ga into SiO(2) followed by vacuum annealing, we have fabricated self-assembled surface Ga nanodots with a high degree of control of nucleation location. The morphology of the Ga nanodots is closely related to Ga dose, showing a critical dose needed for nucleation that results in Ga nanodot formation just below the surface, while at higher doses Ga nanodots form on the surface as metallic Ga droplets. Possible applications include defining nucleation sites for subsequent growth, use as Ga source for GaN or GaAs quantum dots, or as catalyst for nanowire growth.     

Modeling and feedback control of a flexible arm

When a flexible arm is rotated by a motor about an axis through the arm's fixed end, transverse vibration may occur. The motor torque should be controlled in such a way that the motor rotates by a specified angle, while simultaneously stabilizing vibration of the flexible arm so that it is arrested as soon as possible at the end of rotation. In this paper, we first derive a partial differential equation and a set of boundary conditions governing the vibration. Then, a feedback control system which incorporates a dynamic compensator is designed using sensor outputs. A set of experiments has been constructed to demonstrate control strategies for a flexible arm, where a strain gage was used as a vibration sensor and a microcomputer was equipped as a controller. Several satisfactory experimental results are shown.     

Suppressive effect of defatted rice bran on the oxidation of methyl linoleate

The bran collected at each of the five steps of milling yields (98–100%, 96–98%, 94–96%, 92–94% and 90–92%) was defatted. Defatted rice bran (DRB) was added to methyl linoleate (ML) under various conditions, and its suppressive effect on lipid oxidation was kinetically evaluated to investigate the effective use of surplus rice bran. The rate constant, k, empirically evaluated by the Weibull equation for the oxidation of ML with DRB, was lower than that without DRB and decreased with increasing the maximum milling yield of added DRB. The oxidation of ML strongly depended on the added amount of DRB, but the k value was almost constant for a specific amount of DBR added to ML. The dependency of the k value on relative humidity was weak, regardless of the addition of DRB. The difference between the k values for oxidation processes of ML, with and without DRB, increased with increasing temperature.     

MR perfusion imaging by alternate slab width inversion recovery arterial spin labeling (AIRASL): a technique with higher signal-to-noise ratio at 3.0?T

Object  

To propose a new arterial spin labeling (ASL) perfusion-imaging method (alternate slab width inversion recovery ASL: AIRASL) that takes advantage of the qualities of 3.0 T.     

Single-Step Per-O-Sulfonation of Sugar Oligomers with Concomitant 1,6-Anhydro Bridge Formation for Binding Fibroblast Growth Factors

Many circulating cancer-related proteins, such as fibroblast growth factors (FGFs), associate with glycosaminoglycans—particularly heparan sulfate—at the cell surface. Disaccharide analogues of heparan sulfate had previously been identified as the shortest components out of the sugars that bind to FGF-1 and FGF-2. Taking note of the typical pose of l -iduronic acid, we conceived of per-O-sulfonated analogues of such disaccharides, and devised a single-step procedure for per-O-sulfonation of unprotected sugars with concomitant 1,6-anhydro bridge formation to achieve such compounds through direct use of SO₃ ⋅ Et₃N as sulfonation reagent and dimethylformamide as solvent. The synthesized sugars based on the oligomaltose backbone bound FGF-1 and FGF-2 mostly at the sub-micromolar level, although the tetrasaccharide analogue achieved low-nanomolar binding with FGF-2.