Measurements of velocity distributions with a laser doppler imaging system

A laser Doppler imaging system with a TV camera has been constructed and velocity distributions of fluid flow in cross sections of a rectangular channel have been measured. Consequently, it has been found that the system has some advantages in comparison with usual laser Doppler velocimeters, for example, the visualization of flow can be easily achieved.     

Rapid and highly sensitive method for determination of methamphetamine and amphetamine in urine by electron-capture gas chromatography

A rapid and sensitive method for determination of methamphetamine and amphetamine in urine was developed by using electron-capture gas chromatography. The extraction procedure, the experimental conditions for pentafluorobenzoyl derivative formation and the percentage recovery of the drugs from urine are described. The pentafluorobenzoyl derivative of methamphetamine showed a higher electron-capture sensitivity and was detected in at least 23-fold lower concentration than the heptafluorobutyryl derivative which is commonly used as a derivatizing agent for the amine. The detection limit of pentafluorobenzoyl derivatives of methamphetamine and amphetamine was ca. 10 pg. A concentration as low as 10 ng/ml of methamphetamine and amphetamine in urine was easily detected by this method.     

Neutrino mass and cosmological baryon excess in left-right symmetric grand unified theories

In left-right symmetric grand unified theories both the smallness of the neutrino mass and a sizable cosmological baryon excess can be ascribed to a superheavy Majorana lepton. We show, taking SO(10) as the simplest model of this kind, that the largest neutrino mass is constrained to lie between 10^?3 eV and 100 eV in order to give the observed magnitude of baryon excess.     

Glucosidation shifts of allylic and benzylic alcohols in 13C NMR spectroscopy

The ¹³C FT NMR spectra of β-D -glucopyranosides (including their tetraacetates) of several secondary allylic and benzylic alcohols were compared with those of methyl β-D -glucopyranoside and the corresponding parent alcohols. The characeristic glucosidation shifts observed for these alcohols may be applicable to the determination of the absolute configuration of the hydroxy group in these alcohols.     

Mössbauer effect of57Fe in spin frustration system,CsCoCl3

The Mössbauer spectra of 3%⁵⁷Fe doped CsCoCl₃ revealed marked relaxation in all phases. The relaxation was interpreted in terms of propagating domain walls along the magnetic chains together with the transition between the lowest doublet and the low excited singlet levels. The hyperfine field of 24.5T was observed at 4.5K.     

Quantum vacuum energy and singularity-free Kaluza-Klein cosmology

We present a class of cosmological models in which vacuum collapse to curvature singularity is prevented by the generalized gravitational Casimir energy. The mechanism works in higher dimensions, and gives rise to Kaluza-Klein cosmologies free from singularity.     

Pre-filtering Effect in an Iterative Deconvolution Method and Its Application to Signal Recovery in Fiber-Optic Distributed Temperature Sensors

The signal quality of a fiber-optic distributed temperature sensor based on optical time domain reflectometry (OTDR) is improved using a pre-filtering technique in the iterative deconvolution method. Investigation of the performance is proposed using iteration conditions in which recovery rate of the signal-component is equal to that of the unfiltering technique. The recovered signal in the pre-filtering technique gives a good signal-to-noise ratio (SNR), 3 times of the unfiltered signal. Consequently, improvements in the OTDR signal with SNR of from 10 to 100 are obtained under the iterations for both distance and temperature resolutions.