Preparation of thermoplastic elastomer from natural rubber grafted with polystyrene

Thermoplastic elastomer was prepared from deproteinized natural rubber (DPNR) by graft-copolymerization of styrene, which was performed onto rubber particles of about 1 μm in diameter in latex stage with tert-butyl hydroperoxide/tetraethylenepentamine as an initiator. Suitable initiator concentrations were determined to be 3.3 × 10⁻² and 20 × 10⁻² mol/kg-rubber for the graft-coplymerization of styrene of 1.5 and 5.5 mol/kg-rubber, respectively, in which conversion and grafting efficiency of styrene were more than 90 mol% and 80 mol%, respectively. The resulting polystyrene, grafted onto the rubber particles, was characterized by size exclusion chromatography after ozonolysis. Morphology of the DPNR grafted with polystyrene (DPNR-graft-PS) was observed by transmission electron microscopy (TEM). Change in morphology after processing the DPNR-graft-PS at 150 °C was associated with change in mechanical properties, i.e. stress at strain of 1 and stress at break. The outstanding mechanical properties, maintained even after processing, were assigned to the thermoplasticity of the DPNR-graft-PS, based on the high conversion and high grafting efficiency.     

Sharp photonic Crystal Defect Modes and Their Response to Ultrashort Optical Pulses

Single photonic crystal defects based on an air-bridge structure were fabricated. We obtained sharp defect modes with quality factors higher than 600 and observed their response to ultrashort optical pulses by utilizing two-photon absorption.     

Optical Storage Media with Dye-Doped Minute Spheres on Polymer Films

We have fabricated a new optical storage media using minute spheres arranged on a surface relief grating (SRG). Using minute spheres as recording bits, we can limit recordable regions by sphere size, and can realize high resolution reproduction in the plane direction. Surface relief structures were made on a polymer thin film on which we performed diffusion arrangement and adsorptive fixation of minute spheres. The stability of the arranged spheres was confirmed for heating and washing. Furthermore, we used a dipping method for a more simple arrangement of minute spheres on a large area of the substrate and made a monolayer sample of the spheres. We were able to realize a highly sensitive reconstruction of the medium using a confocal optical system as a record and readout system.     

Selection of spectral lines and transition probability data in plasma temperature measurements by photoelectric scanning spectrometry

A strict, comparative investigation of published transition probabilities for thermometric lines and an experimental study of determinations of plasma temperatures were made for improving the accuracy in temperature measurements by the well-known slope method. Four sets of FeI lines which satisfy the requirements for the thermometric lines were selected in the wavelength region of 200–400 nm. A statistical method was used to evaluate degrees of agreement among different sets of transition probabilities. In the experimental study, excitation temperatures of a stabilized arc plasma were determined from relative line-intensities recorded by photoelectric scanning spectrometry. In conclusion, two recommended combinations of lines and transition probability data are presented for the slope temperature measurement. Line pairs used in combination of selected transition probabilities suitable for the two-line method are also given.     

Molecular rotation and lattice dynamical properties for cyclodextrin-ferrocene and some its ring-substituted derivative clathrates

This paper reports the unusual relaxation effect in the⁵⁷Fe Mössbauer spectra of -cyclodextrin(-cyclopentadienyl)(-ethylcyclopentadienyl)iron(II) clathrate. At low temperatures it consists of a simple quadrupole doublet. However, the Mössbauer spectrum collapses to a broad peak at 320 K. This behavior is interpreted in terms of a model that a ferrocene molecule in the cavity of clathrate lattices rotates as temperature is raised. The relaxation reaches a critical rate, a lifetime of the excited nuclear state. The relaxation time for the reorientation of (-cyclopentadienyl)(-ethylcyclopentadienyl)iron(II) in a cavity was 1.2×10^–7 s at 320 K and a barrier to rotation of about 8.8 KJ/mol was estimated.     

A novel synthesis of alkyl phenylsulfinates

Alkyl phenylsulfinates (Ph-SO-OR) were prepared from thiophenol (or diphenyldisulfide) by electrolysis in acetic acid with alcohols and sodium acetate in satisfactory yields.     

Further studies on palytoxin. II. structure of palytoxin

The full structure of palytoxin, a potent coelenterate toxin, is reported.     

Remarks on “theory of scattering in a superconducting state”

Recently the author showed that in a superconductor the existence of scatterers like non-magnetic impurities or phonons in their long wavelength limit never limits the infinite ‘Ohmic’ conductivity which could be expected in the absence of those scatterers. In this paper we discuss the relation of such an infinite conductivity with the freely acceleratable current which is described by the second London equation. Then the results of the former paper are reproduced here by virtue of the canonical transformation technique. It is also suggested that due to the infinite ‘Ohmic’ conductivity giant voltage noises would occur as the temperature approached zero, since then the conductivity is determined by the vanishing density of current carriers (Bogolons) multiplied by an infinite (effective) momentum relaxation time.