Yoshio Shindo

Measurement of surface roughness properties by using image speckle contrast

As a practical monitoring tool for measurements of surface roughness properties, a new instrument is actually constructed on the basis of using the average contrast of image speckle patterns. With this instrument an experimental investigation on the contrast variation of image speckle patterns is conducted systematically for various surface roughnesses of the objects under different conditions of an optical imaging system. It is found that the roughness and correlation length of the objects can be precisely determined from the experimental curve of the contrast variation versus the point spread of the imaging system. The present method using image speckle patterns is superior to the previous one which uses the contrast variation of speckle patterns in the diffraction field.

Phosphorescence from pyrimidine vapor

The phosphorescence from pyrimidine vapor has been observed by a method of time-resolved laser spectroscopy. The phosphorescence spectrum commences at 350.5 nm and consists mainly of three totally symmetric vibrations in the ground state, v6a, v12 and v9a as in the case of the zero-point vibrational level fluorescence of pyrimidine vapor. The phosphorescence quantum yield and lifetime are found to be about 1 × 10−4 and 50 μs.

Phosphorescence of s-triazine vapor

Abstract The phosphorescence of s-triazine vapor has been observed by means of time-resolved emission spectroscopy. The phosphorescence spectrum is diffuse with a faint vibronic structure in the shorter-wavelength region. The phosphorescence quantum yield is 3.0 × 10−5 for excitation at the 620 absorption band of the S0 → S1 transition, and the lifetime is 7.1 × 10−6 s.

Syntheses and reactions of diazaanthracenophanes. Part 8: Syntheses and photochromism of diazaanthracenoparacyclophanes having a substituent on a phenyl ring

Abstract Three diazaanthracenoparacyclophanes ( 1b, 1c and 1d ) having various R 2 substituents (chloro, methoxyl and cyano) on a phenyl ring were synthesized and their photochromic behaviour compared with those of the cyclophanes previously reported by us ( 1a and other derivatives) having various R 1 substituents on the bridged chains. Photoirradiation of the greenish-yellow cyclophanes 1b–1d gave colourless cycloadducts 2b–2d , which reverted to the initial coloured cyclophanes on heating. Compounds 1b–1d exhibited good reproducibilities after several irradiation-heating cycles, similarly to 1a . R 2 substituents accelerated both the photocycloaddition and thermal reversions in the order H 3 ≤ CN, in contrast to the effect of R 1 substituents with bulky substituents on the bridged chains, which accelerated the photocycloaddition and depressed the thermal reversion.

Hypoxic Reduction in Blood Flow Velocity in Pulmonary Arterioles and Capillaries

A small ring chamber (I.D. = 6 mm) was placed on the exposed lung of anaesthetized bullfrogs. A localized hypoxia was induced in the ring chamber by introducing nitrogen in it. Blood flow velocity in pulmonary microvessels was measured by means of a laser Doppler microscope. The mean blood flow velocity was 1.98 +/- 0.45 and 1.52 +/- 0.10 mm/sec during the control condition in arterioles and capillaries, respectively. It was then reduced by the localized hypoxia to 1.63 +/- 0.32 and 1.33 +/- 0.08 mm/sec in arterioles and capillaries, respectively. The reduction, when expressed in the percentage ratio to the control flow velocity in each blood vessel group, was significantly larger in arterioles than in capillaries. A phase delay in the pulsation of the flow velocity contour was detected only in arterioles. These differences between pulmonary arterioles and capillaries in response to the localized hypoxia may be attributed to the dense interconnection of capillary network extending beyond the localized hypoxic area to the normoxic area.