• Journal of the Korean Institute of Gas
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• v.7 no.3 s.20
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• pp.32-43
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• 2003

As this paper is observed the phase equilibrium diagram of mono- (methane) and multi-component(natural gas) hydrates, and the hydrate growth behavior is analysed and compared by the experiments during the reaction. The difference of mono and multi-component hydrates is an induction delay time and a plateau region. And the concentration of component of gases is changed during the reaction in multi-component hydrates and the concentration of components is changed during the decomposition of hydrate according to each decomposing rates of gases. At 6 MPa, 276.65 K and 600 rpm, the induction delay time of multi-component hydrate formation is observed shorter than that of mono-component hydrate formation because the hydrate nuclei of gases except methane form faster than those of methane. And the plateau region of mono-component hydrate is observed distinctly at 0.055 mole of $CH_4$/mole of water and that of multi-component hydrate is observed at 0.04 mole of $CH_4$/mole of water.

• Microbiology and Biotechnology Letters
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• v.7 no.1
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• pp.37-46
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• 1979

In order to investigate the compositional change of the lauan and pine sawdust media during the coltivation of oyster mushroom (Pleurotus ostreatus) chemical components of the two media and mushroom were analized periodically from spawning to ending. The results are summerized as follows: 1) The total yield of mushroom from the lauan sawdust media was 6.39 kg/$m^2$, and from the Pine saw-dust media 6.31 kg/$m^2$, 94％ of which was produced from the first and second cropping period. 2) In both media ash content increased gradually, while organic matter content decreased as the cultivation progressed. Moisture content, which was about 79％ at the time of spawning, decreased a little during the priod of mycelial propagation, after which no change was observed. 3) Total nitrogen content of the two media decreased gradually as the cultivation progressed, and total loss of insoluble nitrogen was greater than that of soluble nitrogen. Amino nitrogen content tended to increase continually. 4) In both media pentosan, $\alpha$-cellulose, lignin and C/N ratio decreased gradually, while the content of reduced sugar, trehalose and mannitol continued to increase. 5) In both media phosphorus, potassium, manganese and zinc decreased, and magnecium, calcium, iron and copper showed irregular changes. 6) CMC-saccharifying and liquefying activity gradually increased from after mycelial propagation to the second cropping, after which it decreased in both media. Xylanase activity rapidly and greatly increased during the second cropping period rather than the first period. At the start of the third cropping period the activity decreased slowly. Protease activity was highest after mycelial propagati, after which it gradually decreased. The pH of the two media decreased as the cultivation progressed. 7) In both media little change was observed in the content of the components of mushroom cropped from the first to the third period, but slight decrease was noticed at the fourth cropping.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.29-35
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• 1992

Total lipids of Korean black soybean (Glycine man Merr) during soaking in water were extracted, purified and fractionated into three lipid classes, and then lipid contents and their fatty acid compositions were investigated. The lipids of the beans consisted of 89.1% neutral lipids, 1.5% glycolipids and 9.4% phospholipids, and these fractions did not change significantly during the soaking period. The neutral lipid fraction of the beans contained 92.1% triglyceride, 3.0% sterol esters and hydrocarbons, 2.8% diglyceride, 1.5% free fatty acids, 0.3% free sterols and 0.3% monoglyceride, and no significant changes were found in the composition of neutral lipid fraction from the soaked beans. Major components of the glycolipid fraction were esterified steryl glycosides (43.6%), steryl glycosides (26.6%) and digalactosyl diglycerides (14.5%), and these fractions did not change significantly during the soaking period. On the other hand, phosphatidyl choline (41.6%) and phosphatidyl ethanolamine (39.5%) were most abundant components found in the phospholipid fraction, and the contents of phospholipids changed a little during the soaking period. Linoleic acid, oleic acid and palmitic acid were the major fatty acids found in total lipids, neutral lipids, glycolipids and phospholipids. A few changes in the major fatty acid compositions of phospholipids were observed during the soaking period.

• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.77-85
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• 2001

This paper proposes a method of time-scale modification of polyphonic audio signals based on a sinusoidal model. The signals are modeled with sinusoidal component and noise component. A multiresolution filter bank is designed which splits the input signal into six octave-spaced subbands without aliasing and sinusoidal modeling is applied to each subband signal. To alleviate smearing of transients in time-scale modification a dynamic segmentation method is applied to subbands which determines the analysis-synthesis frame size adaptively to fit time-frequency characteristics of the subband signal. For extracting sinusoidal components and calculating their parameters matching pursuit algorithm is applied to each analysis frame of subband signal. In accordance with spectrum analysis a psychoacoustic model implementing the effect of frequency masking is incorporated with matching pursuit to provide a resonable stop condition of iteration and reduce the number of sinusoids. The noise component obtained by subtracting the synthesized signal with sinusoidal components from the original signal is modeled by line-segment model of short time spectrum envelope. For various polyphonic audio signals the result of simulation shows suggested sinusoidal modeling can synthesize original signal without loss of perceptual quality and do more robust and high quality time-scale modification for large scale factor because of representing transients without any perceptual loss.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.395-404
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• 2008

We explore the linkage between the long term variability of the Sun and earth's climate change by analysing periodicities of time series of solar proxies and global temperature anomalies. We apply the power spectral estimation method named as the periodgram to solar proxies and global temperature anomalies. We also decompose global temperature anomalies and reconstructed total solar irradiance into each local variability components by applying the EMD (Empirical Mode Decomposition) and MODWT MRA (Maximal Overlap Discrete Wavelet Multi Resolution Analysis). Powers for solar proxies at low frequencies are lower than those of high frequencies. On the other hand, powers for temperature anomalies show the other way. We fail to decompose components which having lager than 40 year variabilities from EMD, but both residuals are well decomposed respectively. We determine solar induced components from the time series of temperature anomalies and obtain 39% solar contribution on the recent global warming. We discuss the climate system can be approximated with the second order differential equation since the climate sensitivity can only determine the output amplitude of the signal.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.314-321
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• 1999

This study was performed to test application possibility of electronic nose with 32 conducting polymer sensor arrays for aroma analysis of persimmon vinegar. The 20, 30, 40, 50, 60, and $70^{\circ}Bx$ persimmon vinegar concentrates were prepared by vacuum concentration at $55^{\circ}C$. The recovery yield of water soluble solid to concentrates was 55.5% on $20^{\circ}Bx$ persimmon vinegar concentrate. As the concentration of persimmon vinegar concentrates increased, pH of concentrates increased and acidity as acetic acid decreased. From sensory evaluation for persimmon vinegar concentrates, as the concentration of persimmon vinegar concentrates increased, their cooking odor and umami taste increased, sour taste and acidic odor decreased, salty odor and astringency were not changed. Aroma analysis by electronic nose (AromaScan) showed no difference in normalized pattern and odor intensity among persimmon vinegar concentrates. All quality factors among concentrates also were less than 1.042. And so the electronic nose with conducting polymer sensor was not suitable for aroma analysis of persimmon vinegar concentrate.

• Journal of Ginseng Research
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• v.30 no.1
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• pp.15-21
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• 2006

This study was carried out to determine the antioxidative activities of tissue cells of mouse kidney isolated from mice fed with different formulation of drinks. The swimming ability of experimental groups without caffeine showed the same pattern, but caffeine group decreased slightly. Superoxide dismutase(SOD) and catalase(CAT) activities of caffeine-containing groups were decreased significantly, but the control and ginseng-containing groups were increased. Hydroperoxide contents did not increase significantly all experimental groups. Hydroperoxlde contents of the control and ginseng-containing groups were similar, but caffeine-containing groups increased. Compared to the control and ginseng-containing groups, lipid peroxidation level and protein contents in caffeine-containing groups were decreased significantly. In conclusion, the antioxidative activities of mouse kidney isolated from mice fed with ginseng-containing products was increased slightly.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.610-622
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• 2008

Moving object segmentation is an essential technique for various video surveillance applications. The result of moving object segmentation often contains shadow regions caused by the color difference of shadow pixels. Hence, moving object segmentation is usually followed by a shadow elimination process to remove the false detection results. The common assumption adopted in previous works is that, under the illumination variation, the value of chromaticity components are preserved while the value of intensity component is changed. Hence, color transforms which separates luminance component and chromaticity component are usually utilized to remove shadow pixels. In this paper, various color spaces (YCbCr, HSI, normalized rgb, Yxy, Lab, c1c2c3) are examined to find the most appropriate color space for shadow elimination. So far, there have been some research efforts to compare the influence of various color spaces for shadow elimination. However, previous efforts are somewhat insufficient to compare the color distortions under illumination change in diverse color spaces, since they used a specific shadow elimination scheme or different thresholds for different color spaces. In this paper, to relieve the limitations of previous works, (1) the amount of gradients in shadow boundaries drawn to uniform colored regions are examined only for chromaticity components to compare the color distortion under illumination change and (2) the accuracy of background subtraction are analyzed via RoC curves to compare different color spaces without the problem of threshold level selection. Through experiments on real video sequences, YCbCr and normalized rgb color spaces showed good results for shadow elimination among various color spaces used for the experiments.

• Food Science and Preservation
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• v.21 no.6
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• pp.784-789
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• 2014

This work aimed to investigate the changes in the nutrient contents and antioxidant activity of Peucedanum japonicum Thunb. by ripening stage, growing condition, and blanching. The crude protein content of the young leaves (3.6~4.3%) was higher than that of the mature leaves (3.1~3.9%). Higher calcium contents were observed in the greenhouse-cultivated samples (225.9~259.2 mg/100 g) compared to the field-cultivated samples (178.5~199.5 mg/100 g). The vitamin C and folate contents (18.1~83.8 and 175.8~220.2 mg/100 g, respectively) of the field-cultivated samples were significantly (p<0.05) higher than those of the greenhouse-cultivated samples (13.1~57.7 and 133.0~148.8 mg/100 g, respectively). The growing condition and blanching were significant factors affecting the changes in the vitamin and polyphenol contents. The ${\beta}$ carotene contents of the blanched samples increased 2.6-fold compared to those of the raw samples. The total polyphenol contents (10.2~17.1 mg/g extract) and DPPH radical scavenging activity ($IC_{50}=2.0{\sim}3.0mg/ml$) of the blanched samples were significantly (p<0.05) higher than those of the raw samples (1.8~4.3 and $IC_{50}=16.2{\sim}21.1mg/ml$, respectively).

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.1
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• pp.61-66
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• 1985

Cooked rice was prepared by the conventional cooking method being used among Korean families. The bottom layer (very slightly roasted and charred) and upper layer of the cooked rice in a cooking vessel were collected separately in order to determine the chemical changes and volatile carbonyl formation occurring in rice during the cooking process. Amino acids, especially free amino acid contents were reduced with the decrease of reducing sugar in rice after cooking. A little change was shown in the fatty acid composition of lipid fractions, however, decreased iodine values and increased fatty acid values were observed after cooking process. Volatile carbonyl compounds from cooked rice were isolated and 8 carbonyls of them were identified. A significant difference of relative composition of the identified carbonyls was found between the upper layer and bottom layer of cooked rice. Generally, the cooked rice obtained from the bottom layer had shown a little more changes in chemical composition and a stronger browning flavour than those of the upper layer of cooked rice.