Objectives: The purpose of this study was to investigate the relationship between compression force and hardness values in ultrasound elastography. Methods: Ultrasound elastography was performed using an elastography phantom, comprising inclusions with different elasticities and echogenicities. The compression force was set to approximately 100 gw (light force) and approximately 500 gw (heavy force). The elasticity index (EI) of the inclusion was measured. The EI was a relative hardness value of a structure within an elastographic image. Similarly, the EI of the background was measured as a reference. The elasticity ratio (ER) was calculated as the EI of the inclusion divided by the EI of the reference. Results: The hardness of the phantom could be discerned with both the EI and ER, regardless of the compression force. The EI and ER with heavy force tended to be higher than those with light force, but the difference was not significant. A strong correlation was observed between the EI and ER of soft structures, whereas the correlation between the EI and ER of hard structures was weak, and the ER values varied widely.

Zeolites are usually synthesized by hydrothermal reactions using monomeric or polymeric Al- and Si-containing precursors, whereas simple and direct routes for the rational synthesis of zeolites remain elusive. In this...

The characteristics of fading of nylon, polyester and cellulose triacetate fabrics dyed with C I Disperse Blue 79:1 were investigated on a radiant energy basis by exposure to monochromatic light. Action spectra were compiled to show the strong effect of substrate on the fading with respect to radiant wavelength. Peaks were observed with maxima at 246 nm on cellulose triacetate, 310 nm on polyester and 262 nm on nylon in the fading. The nylon substrate caused the least light-fastness compared with the polyester and cellulose triacetate substrates, showing a wide wavelength range in the fading response. Moreover, it was estimated through color change examinations that the reduction of the nitro group to the amino group occurred on the nylon substrate, whereas the destruction of the azo group of the dye prevailed on the polyester and cellulose triacetate substrates under light irradiation.

In order to clarify the viscoelastic properties of four commercial resins for crown and bridge, the dynamic shear modulus (G'), Knoop hardness (KHN), filler content, quantity of unreacted substance and thermal expansion were measured. The results were as follows. The G' (37•Ž) of each material ranged from 2.61•`11.1GPa, and gradually decreased with increasing temperature. KHN (23•Ž) ranged from 29.4 to 120, and the most significant correlation (0.999) was found between G' and KHN. Of the relationship among G', filler content and unreacted substance, there was a highly significant correlation (0.980) between G' and filler content. The coefficient of linear-thermal expansion (ƒ¿) also ranged from 17.9•`65.0•~10-6/•Ž (25-60•Ž), and gether with an increase in temperature. Key words: Viscoelastic property, Resin for crown and bridge, Thermal expansion VISCOELASTIC PROPERTIES OF CROWN RESIN to those of resin composites because of the similar ingredients and composition. Furthermore, it is generally known that resins for crown and bridge are viscoelastic, and that viscoelastic properties are affected remarkably by experimental conditions such

Light fastness of CI Disperse Blue 165 dye on cellulose triacetate, polyester and nylon fabric substrates exposed to monochromatic light was examined on a radiant energy basis. The action spectra indicated a strong effect on the substrate‐fading characteristics: nylon exhibited poorer light fastness in the visible and ultraviolet light range than polyester and cellulose triacetate. Two specific fading peaks were found for the nylon substrate, which were different to those found for the polyester and cellulose substrates. It was shown that polyester exhibited the best light fastness properties overall. The colour changes in the fading process suggested that the fading products of the dye on nylon (where reduction occurred) were different from those on the polyester and cellulose triacetate substrates (where oxidation occurred).