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Raman and Brillouin light-scattering spectroscopy have been used to study variety of materials including Ag3AsS3 (proustite), Ag3SbS3 (pyrargyrite), NaKC4H406.4H20 (Rochelle salt), CaC4H406.4H20 (Calcium tartrate), Li2B407 (lithium diborate), BaTiO3 (barium titanate), Pb5Ge3011 (lead germanate), C3N3H3 (s-triazine) and SrTi03 (strontium titanate). Most of these materials undergo structural phase transitions of one kind of another and the spectroscopic date have been used to help identify and characterise these transitions where they exist. The presence of order-disorder phenomena is shown to be important in several instances but not necessarily directly involved in the phase-transition mechanism. In a subsidiary study a molecular crystal dynamics computer simulation has been carried out, successfully modelling the anharmonic behaviour of the crystal naphthalene.

This report describes light scattering measurements from a variety of materials which undergo structural phase transitions. The materials studied include Pb5Ge3O11, SrTiO3, BaTiO3, RbCaF3, KMnF3, KH2PO4, KD2PO4, K2SeO4, BaMnF4, Ag3AsS3, AgI and Li2B4O7. Effects studied include: the influence of defects; the spectral response of 'soft modes'; the existence of dynamic precursor clusters; central peaks; incommensurate excitations; disorder effects in superionic and other crystals. (Author)

This report describes light scattering measurements from a variety of materials which undergo structural phase transitions. The materials studied include boracites, lead germanate and perovskites and the studies have found new transitions, determined the nature of the soft mode and detailed the changes in the spectra due to the presence or addition of impurities. In addition associated theoretical work has questioned the validity of the usual way of interpreting soft mode results obtained from light scattering techniques. An experiment was also performed to study the light scattering from magnons in a mixed antiferromagnet. (Author)

The Goldmann perimeter was used to study retinal sensitivity in different age groups with particular emphasis on the youngest (6-11 years). Results from the older subjects confirmed previous findings on the deterioration of sensitivity with age. It was also found that the younger the subject the lower the sensitivity at both fovea and periphery compared with the optimum level of performance of the 20 year old group, but by far the most dramatic difference occurred in peripheral sensitivity. These findings provide evidence of a developmental increase in peripheral sensitivity between 6 and 11 years. (Author)

It is the concern of this paper to examine not only the effectiveness of tests for detecting colour confusion but also their usefulness in assessing colour vision generally. In part 1, problems of administration and age and the question of the basic elements of such tests are discussed. The existing theory of colour vision and colour defect is outlined and the principle of objective colour specification, which is believed to be valuable for understanding these tests, is introduced. (Author)

Data for the study was obtained from test results of male applicants for posts as colour matchers in the laboratory of a plastics firm in Scotland. Their mean age was 28 years, and they were all highly motivated observers who had no previous experience of using the tintometer, although one of them had previously been colour matchers. (Author)