Relaxation processes in glasses as shown by optical attenuation experiments

Some optical attenuation experiments on both bulk glasses and cladded glass fibres (fibre optics) are described. They reveal the presence of relaxation processes in the glass in its transformation range.     

Transmission measurements in optical glass with an improved twin-beam spectrophotometer

Improvements are described to a twin-beam spectrophotometer for measuring the bulk attenuation of optical quality glass over the wavelength range 0.4 to 1.1 m. Results are presented for a number of glasses and a comparison is shown between the attenuation of a multimode fibre with a core of F7 glass and various samples of F7 rods.     

An experimental study of ω neutral decays

The neutral branching ratios of the ω meson have been determined by measuring the c.m. momentum spectrum of single γ's from ω decay. The sample of 400 ω events after background subtraction yields an upper limit of (ω → ηγ)/(ω → neutrals) < 25% (90% confidence). The fit with ω → π⁰γ only cannot be excluded. However, the best fit is obtained with the ratios (ω →π⁰γ)/(ω → neutrals) = (78±7)% and (ω → π⁰π⁰γ)/(ω → neutrals) = (22 ± 7)%.     

Theory of dispersion in lossless multimode optical fibres

Using the ray propagation model generalized expressions for the impulse response of multimode fibres have been derived. The analysis has been applied to lossless fibres for pulses having both gaussian and lambertian spatial distributions as well as impulse and gaussian temporal distributions. Detailed results are given for output pulse shapes and fibre dispersions for various configurations.     

Harnuntersuchung

Ohne Zusammenfassung     

An optical fibre sensor for the measurement of pressure

This paper describes the design, construction and testing of a fibre optic pressure sensor based on a reflecting Fabry-Perot etalon. The etalon comprised one fixed mirror and a second mirror designed to flex under the action of the pressure being monitored. A single multimode fibre was used to connect the passive, remote sensor to the transmitter/receiver section, and dual wavelength referencing was used to eliminate the effects of bending-induced attenuation in the fibre.     

Particle ratios in inclusive electroproduction from hydrogen and deuterium

We present a high statistics study of particle ratios in electroproduction of forward hadrons. The π⁺/π^? ratios for a proton target rise monotonically to a value of 2.4 ± 0.2 at Q² of 3 (GeV/c)² and for a neutron target average 1.16 ± 0.04 from Q² of 0.35 to 3 (GeV/c)². We report the first data on electroproduction of $\text{p}$, and measure the cross sections of K^±, p, and $\text{p}$ relative to pions as a function of Q².     

A mild,chemoselective protocol for the removal of thioketals and thioacetals mediated by Dess-Martin periodinane

[reaction: see text] This paper describes the development of a useful procedure for the removal of thioacetals and thioketals using Dess-Martin periodinane (DMP) reagent. In contrast to existing methods, this protocol offers general reactivity, compatibility with a wide range of functional groups, and convenient reaction times. Also discussed are chemoselectivity experiments involving functionalities that may be subject to oxidation by DMP, qualitative effects of substrate on hydrolysis rate, and direct thioacetal to acetal conversions.