Effect Of Spectral Distribution Research Articles

The relationship between internode elongation of soybean stems and spectral distribution of light in the canopy under different plant densities

ABSTRACT The present study carried out with a field plot experiment and light environment simulation experiment in 2017 to assess the effect of spectral distribution on internode elongation in soybean canopy. Henong 60 and Heinong 48 were used as the experimental materials. The spectral distribution in the soybean canopy was studied under four planting densities 200,000(D20), 300,000(D30), 400,000(D40) and 500,000(D50) plant ha−1. Meanwhile, a pot experiment of light environment simulation with light-emitting diode (LED) was carried out to further analyze the effects of light quantity and quality on the elongation of soybean seedlings. The results showed that the intensity of PAR, blue light, red light and far-red light in soybean canopy decreased by varying degrees with density and canopy depth increasing, and the decrease of PAR and R/FR led to significant elongation of internodes and plant height in high density. The spectral intensity in the middle and base of the canopy was strongly reduced, resulting in the strongest internode elongation in the middle of soybean stem. The increase in soybean plant height was also mainly due to the internode elongation in the middle at high density. In addition, the mono-light of far-red light could promote the internode elongation, while the red light and blue light acted as inhibitors and the inhibitory effect of blue light was even greater.

Effects of Spectral Distribution on Radiative Heating of Food

Effects of Spectral Distribution on Radiative Heating of Food

Characterization and calibration of broadband ultraviolet radiometers

The band responsivities of radiometers for measuring ultraviolet irradiance or dosage in the UVA, UVB and UVC spectral regions are source-dependent and require spectrally weighted measurements for calibration. Currently, however, many industrial users lack knowledge of this and may use a radiometer originally calibrated using one particular type of source to measure UV radiation from a source of a different type. Worse still, when this radiometer is later sent for recalibration, the calibration laboratory could use a source of a third type. This problem results in considerable discrepancies, as high as 20 % to 50 %, in the calibration of UV radiometers, and consequent errors in actual measurements. Efforts are being made by the International Commission on Illumination (CIE) to standardize the calibration method and industrial uses of UV radiometers. This paper reviews the measurement principles of broadband radiometers and examines, both theoretically and experimentally, the effects of spectral distribution on the responsivities of several commonly used UV sources. The analysis agrees well with the experimental results. The methods of characterization and calibration of these radiometers are also discussed in detail.

照明光の分光分布が白色感に及ぼす影響

照明光の分光分布が白色感に及ぼす影響

Effect of spectral distribution on isomerization of bilirubin in vivo

The purpose of our study was to compare the effects of narrow-spectrum blue light and broad-spectrum white light on the production of bilirubin photo-isomers in human infants with jaundice. Twelve preterm infants were studied under both white and blue light. Irradiance at 450 nm was controlled at 12 microW/cm2/nm for both light sources. Each light condition (white or blue) was administered for 12 hours. Bilirubin isomers (4Z,15E-bilirubin and lumirubin) were measured before therapy and after 12 hours of each sequential light condition. The percentage of 4Z,15E-bilirubin was greater under blue light than under white light (P less than 0.01) phototherapy. There was no significant difference in percentage lumirubin under white or blue light therapy. Our data indicate that blue light is more effective than white light in producing 4Z,15E-bilirubin in vivo. Our study demonstrates that when irradiance in the bilirubin absorbance spectrum is constant, the color of light (spectral distribution) will determine the relative concentrations of photo-isomers produced.

The effects of spectral distribution on x-ray image quality

Broad and monoenergetic x-ray spectra were analyzed with a computer to determine the photon signal-to-noise ratio, exposure modulation, and integral dose in a simulated caries detection task. Assuming an ideal exposure geometry, it was possible to compute relative values which permit meaningful comparison of spectra in terms of these parameters. The broad spectra were measured with a high-resolution spectrometer system. The data were corrected for spurious effects and analyzed with an idealized attenuation model. The results suggest that spectral changes brought about by even relatively small amounts of selective filtration in the region between 25 and 45 keV. measurably influence the potential for diagnostic quality.

Effects of spectral distribution of radiant energy on cutaneous burn production in man and the rat.

Effects of spectral distribution of radiant energy on cutaneous burn production in man and the rat.