A laboratory experiment and two field experiments were conducted to investigate the effects of lamp spectral power distribution on perceived scene brightness in nighttime lit streets and reveal the mechanisms of the perception of scene brightness. The experimental results confirmed the Purkinje effect in which a scene appears brighter when it is illuminated by lamps with enriched short-wavelength radiation. The results also suggest that perceived scene brightness corresponds to mesopic luminances within the range of the experimental conditions and short-wavelength cones contribute to the perception of scene brightness to a limited degree at mesopic light levels.
This paper describes an original method for measuring pesticide residue. Recently, the demand for measurement of pesticide residue has increased because the concern of safety of the consumer's food has risen. Furthermore, the dispersion of the pesticide (drift) has become an urgent problem. However, existing methods involve destructive inspection, and a lot of time and proficiency is necessary for the analysis. In this study, to solve those problems, we propose the application of infrared spectroscopy, which is a nondestructive measurement technique. This is a measuring method that assumes the adhesion density of agricultural chemicals using the IR spectrum and SIMCA.
We focus on improvement of office lighting and created a color lighting system that can adjust chroma of a given hue, using full-color LEDs. Here, we developed an algorithm that calculates the optimal ratio by adjusting the intensity of the target color while retaining the target illuminance. For many colors, we investigated whether the intensity of color is acceptable for office workers by experiments using the proposed system, and we applied the color intensity obtained to uv chromaticity diagram. As a result of the experiments, the acceptable region on the chromaticity diagram showed significantly individual different and is classified into three patterns. These results indicate the acceptable region on a chromaticity diagram for office lighting.
In this experiment, observers estimated the perceived brightness of a central and surrounding area under varying luminances, luminance ratios, and central area sizes by using a 13-step scale in a lighting condition with two different luminance areas. 1. Perceived brightness in the surrounding area was darker than usual in the high central luminance condition. 2. Perceived brightness in the surrounding area was different from that in the central area and changed independently. 3. Perceived brightness had a linear relation to the luminance logarithm in two areas, consistent with Weber & Fechner's logarithmic law. In addition, the linear regressions' coefficients changed depending on the contrasts (luminance ratio) and central area sizes.
Hot-filament chemical vapor deposition (CVD) of diamond was used to obtain polycrystalline diamond thin film electrodes on silicon substrates. Deposition was carried out by using a mixture of CH4/H2 gases through a heated reactor in which a hot tungsten filament was held near the substrates. The films were evaluated by using a scanning electron microscope (SEM), Raman spectroscopy, and a photoacoustic method. The breakdown voltages for the electrodes of the CVD diamond thin films were measured under various Ne pressures by using a V-Q Lissajous method. The secondary electron emission coefficient of the diamond thin film electrodes increased as Raman spectra intensity at 1333 cm-1 and optical penetration depth increased.