• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.755-761
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• 2017

This study was conducted to establish an analytical method using an HPLC system equipped with a photodiode array (PDA) detector for the quality control of raw materials and cosmeceuticals containing fucoxanthin as an active ingredient. The column was octadecyl-functionalized silica gel and the measurement wavelength of the PDA was set to 499 nm. To validate the analytical method, the linearity of the calibration curve, detection limit, reproducibility and recovery rate were investigated and good results were obtained. The correlation coefficient of the calibration curve was 1.000 and the linearity was good in the concentration range of 0.5 ~ 100 ppm. Moreover, the limit of detection (LOD) was 0.1 ppm and the limit of quantification (LOQ) was 0.5 ppm. The results of the peak reproducibility test used for evaluating the system suitability showed that the RSD (n = 5) of the peak area was 2.0% and that of the retention time was 0.09%. In the spiking test, the recovery rate was $101.6{\pm}0.77%$. The fucoxanthin contents of the two kinds of fucoxanthin-containing raw materials were $49.6{\pm}3.3%$ and $1.03{\pm}0.016%$, respectively. In addition, the fucoxanthin content in the test product, which was intended to be 150 ppm, was $156.7{\pm}4.7ppm$. From the above results, it was concluded that this method could be applied to the quantitative analysis of fucoxanthin in cosmeceuticals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.565-569
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• 2011

Validation of quercetin as a marker compound in the standardization of Changnyeong onion extract developed for functional health food was attempted by analytical method. The specificity was satisfied with retention time and photo diode array (PDA) spectrum by analysis of quercetin using HPLC and comparison with standard compound. It showed a high linearity in the calibration curve as coefficient of correlation ($R^2$) of 0.9986, and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.2 mg/L and 0.5 mg/L, respectively. Recovery rate test with quercetin concentration of 0.05, 0.075 and 0.1 mg/mL was revealed in the high range of 82.36~95.26%, 82.70~98.24% and 87.91~95.11%, respectively. The intra-day and inter-day precision in quercetin for Changnyeong onion extracts was 0.10~3.28% and 0.96~5.79%, respectively. Therefore, application of quercetin was validated in analytical method as a marker compound in Changnyeong onion extracts.

• Korean journal of applied entomology
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• v.27 no.2
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• pp.103-110
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• 1988

The behavior and circadian rhythm of emergence, copulation and oviposition in the Oriental tobacco budworm (Heliothis assulta Guenee) were studied to obtain the following results. More than three quarters of adults emerged within 3 hours after the light-off. It took about 33 min for an adult to expand and tan its wings after emergence. Adult male showed a sequential pattern of mating behavior, such as antennal movement, wing elevation and vibration, exten¬sion of hairpencils, and tapping of female ovipositor leading to a copulation. However, adult female revealed a rather simple behavior, such as protraction and retraction of her terminal abdomen and vibration of wings. All of the mating took place during the early part of the scotophase, with the peak from 1 hr to 2 hrs after the light-off. But the mating peak in virgin females tended to advance with age. Adult females showed the highest rate of mating among 24 hr-olds and the rate declined with age. The rate of first matings in males gave a very similar pattern to that of females. The duration of copulation was $77\pm$14min. Oviposition occurred throughout the entire scotophase, with the peak during the first 2 hrs. The most nu¬mber of eggs deposited daily was seen on the 3rd day after the mating. Mating rate, number of eggs laid and longevity we~e compared under different sex ratio. Unmated adults lived longer than mated adults.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.323-328
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• 2006

An experiment was conducted to investigate the effects of dietary betaine on egg production, estradiol, progesterone, and melatonin secretion in laying hens. Seventy two ISA-Brown laying hens were placed into individual cage and fed four different levels of betaine (0, 300, 600, 1,200 ppm) in diets for four weeks. Basal diets were mainly mixed with corn-soybean and contained 2,800 kcal/kg ME and 16% CP. Dietary supplementation of betaine showed significantly higher (p<0.05) egg weight and daily eggmass than controls, but did not have consistent influence on the egg production. The serum estradiol was statistically different in betaine treatments compared to that of control (p<0.05). No significant changes in serum progesterone concentrations were observed by the addition of betaine in diets. Serum melatonin concentrations also increased with betaine supplementation in diets (p<0.05). The results of this study indicate that the dietary betaine may contribute to increase daily eggmass, serum estradiol and melatonin concentration in laying hens.

• The Journal of the Acoustical Society of Korea
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• v.37 no.4
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• pp.181-187
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• 2018

In this paper, sound absorption of micro-perforated elastic plates installed in an impedance tube of a circular cross-section is discussed using an analytic method. Vibration of the plates and sound pressure fields inside the duct are expressed in terms of an infinite series of modal functions, where modal functions in the radial direction is given in terms of the Bessel functions. Under the plane wave assumption, a low frequency approximation is derived by including the first few plate modes, and the sound absorption coefficient is given in terms of an equivalent impedance of a single surface. The sound absorption coefficient using the proposed formula is in excellent agreement with the result by the FEM (Finite Element Method), and shows dips and peaks at the natural frequencies of the plate. When the perforation ratio is very small, the sound absorption coefficient is dominated by the vibration effect. However, when the perforation ratio reaches a certain value, the sound absorption is mainly governed by the rigid MPP (Micro-Perforated Plate), while the vibration effect becomes very small.

• Elastomers and Composites
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• v.35 no.2
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• pp.138-148
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• 2000

In order to investigate the possibility of EPDM micro cellular pad (MCP) as an impact sound insulation product, we studied static/dynamic properties and vibration transfer characteristics of EPDM MCP depending on shape, thickness, degrees of foaming by using material test system (MTS) and lab scale mock-up test apparatus. Static/dynamic rigidity is increased when shape is simple. thickness and degrees of foaming low. We could see that dynamic stiffness is proportional to the transmissibility of EPDM MCP. When dynamic stiffness is increased, characteristic peak at transmissibility curve moves high frequency range or snows increase of maximum value of transmissibility. For lab scale mock-up test and finite element method, EPDM MCP shows low vibration velocity and superior mode shape to just concrete plus slab structure. We could confirm that possibility of EPDM MCP as a impact sound insulation product is high.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.266-271
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• 2003

The reflectance spectrum of optical films thicker than a few microns shows an intensity oscillation due to interference. Since the spectral period of the oscillation is inversely related to film thickness, the thickness of an optical film can be determined from the spectral frequency of the oscillation. For rapid data processing, the spectral frequency is obtained by use of a Fast Fourier Transformation technique. The conventional method of applying a Fast Fourier Transformation to the reflectance spectrum versus photon energy is modified so as to clear the ambiguity in choosing the proper effective refractive index value and to prevent the broadening of the Fourier transformed peak due to the refractive index dispersion. This technique of modified Fast Fourier Transformation is suggested by the authors for the first time to their knowledge. From the analysis of the calculated reflectance spectrum of a 30-${\mu}{\textrm}{m}$-thick dielectric film. it is shown to improve the accuracy in determining film thickness by a great amount. The improved accuracy of the modified Fast Fourier Transformation is also confirmed from the analysis of the reflectance spectra of a sample with 80-${\mu}{\textrm}{m}$-thick cover layer and 13-${\mu}{\textrm}{m}$-thick spacer layer on a PC substrate.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.143-149
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• 2017

This study was carried out to collect basic data on the egg laying performance and disease occurrence on animal welfare-approved farms (AWAF) for laying hens with different housing types (windowless, open, and free-range house) and strains (Hy-line, Lohmann). Age at first egg laying was 151 d in the windowless house and 141 d in both the open and free-range houses, and the percentage peaks of each farm were 91.8%, 92.9%, and 86.3%. Average egg production according to housing types were 70.9%, 77.4%, and 65.6% at 18~38 wk old and 91.1%, 90.1%, and 76.2% at 32~36 wk. The average dirty and cracked egg ratio of the windowless, open, and free-range houses was 2.84%, 1.15%, and 0.23%, respectively. Mortality in the open house was lower than the other house types. Age of first egg laying for the Hy-line strain was 155 d and that for the Lohmann strain was 157 d, and the percentage peaks of the two strains were 92.9% (252 d) and 87.2% (237 d), respectively. Average egg production of the strains was 83.7% and 76.9%, respectively. The average dirty and cracked egg ratio of the Hy-Line and Lohmann strains was 3.85% and 2.97%, respectively. Mortality of the Hy-Line strain was lower than that of the Lohmann strain. There were significant differences (P<0.05) in the egg weight, HU, and egg yolk color of chickens raised in the open house compared with those of chickens raised in the other house types. In terms of antibody titer, that for Newcastle disease in open house chickens was lower than that of chickens raised in windowless and free-range houses. The antibody titer for low pathogenic avian influenza, avian infectious bronchitis, and avian pneumovirus was high at over 3.0 in all three farms. SG, Salmonella enteritidis, Salmonella pullorum, fowl adenovirus infection, and infectious laryngotrachitis were not detected in any of the three house types. The number of AWAF for laying hens has continuously increased in Korea, but there is currently little data on the housing types used on the AWAF for laying hens. Therefore, the results of the present study, in which analyzed the laying performance and disease occurrence on AWAF for laying hens, can use as basic data for the improvement of performance and prevention of disease on further AWFA for laying hens.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.612-618
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• 2016

The aim of this study is to investigate the effects of stray light originating from the blue-light blocking lens on the quality of the image. After designing the ideal spectacle lens, anti-reflection spectacle lens without internal reflection, anti-reflection spectacle lens with internal reflection, and blue-light blocking lens with internal reflection, the light intensity distribution and stray light distribution were derived. The designed spectacle lenses are meniscus lenses with a refractive power of 0.00 D, refractive index of 1.56, and a radius of 155.15 mm. The peaks of reflectance of the 4 types of blue-light blocking lenses are in the range between 430 nm and 440 nm, and their reflectances are 5%, 10%, 15%, and 20%, respectively. According to the analysis results, as the reflectance of the blue-light blocking lens increases, the light intensity in the center of the lens decreases and the intensity of the stray light in the center-periphery and periphery of the lens increases. This trend appeared to intensify with increasing reflectance of the blue-light blocking lenses. Because the increase in the reflectance of the blue-light blocking lens degrades the quality of the image by increasing the intensity of the stray light in the center-periphery and periphery of the lens, its reflectance needs to be adjusted by varying the blue-light blocking ratio and the luminous transmittance, in order to diminish the level of visual discomfort.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.311-321
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• 2019

Greenhouse farmers often use thermal screens to reduce greenhouse heating expenses during the winter, and for shade during hot, sunny days in the summer, as it is an inexpensive solution to temperature control relative to other available options. However, accurate measurements of their emitted and absorbed radiations are important for the selection of suitable screens that offer maximum performance. Material's ability to save energy is highly dependent on these properties. Limited studies have investigated the measurement of these properties under natural conditions, but they are only applicable to materials having partial porosities. In this work, we describe a new radiation balance method for determining emissive power and absorptive capacity, as well as reflectivity, transmissivity and emissivity of materials having complete and partial transparency by using pyrgeometer and net radiometer. In this study, four materials with zero porosity, were tested. The emissivity value of PE, LD-13, LD-15 and PH-20 was $0.439{\pm}0.020$, $0.460{\pm}0.010$, $0.454{\pm}0.004$, and $0.499{\pm}0.006$, respectively. All tested samples showed high emitted radiation as compared to absorbed radiation.