• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.247-255
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• 2005

ice yield and plant growth response to nitrogen (N) fertilizer may vary within a field, probably due to spatially variable soil conditions. An experiment designed for studying the response of rice yield to different rates of N in combination with variable soil conditions was carried out at a field where spatial variation in soil properties, plant growth, and yield across the field was documented from our previous studies for two years. The field with area of 6,600 m2 was divided into six strips running east-west so that variable soil conditions could be included in each strip. Each strip was subjected to different N application level (six levels from 0 to 165kg/ha), and schematically divided into 12 grids $(10m \times10m\;for\;each\;grid)$ for sampling and measurement of plant growth and rice grain yield. Most of plant growth parameters and rice yield showed high variations even at the same N fertilizer level due to the spatially variable soil condition. However, the maximum plant growth and yield response to N fertilizer rate that was analyzed using boundary line analysis followed the Mitcherlich equation (negative exponential function), approaching a maximum value with increasing N fertilizer rate. Assuming the obtainable maximum rice yield is constrained by a limiting soil property, the following model to predict rice grain yield was obtained: $Y=10765{1-0.4704^*EXP(-0.0117^*FN)}^*MIN(I-{clay},\;I_{om},\;I_{cec},\;I_{TN},\; I_{Si})$ where FN is N fertilizer rate (kg/ha), I is index for subscripted soil properties, and MIN is an operator for selecting the minimum value. The observed and predicted yield was well fitted to 1:1 line (Y=X) with determination coefficient of 0.564. As this result was obtained in a very limited condition and did not explain the yield variability so high, this result may not be applied to practical N management. However, this approach has potential for quantifying the grain yield response to N fertilizer rate under variable soil conditions and formulating the site-specific N prescription for the management of spatial yield variability in a field if sufficient data set is acquired for boundary line analysis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.spc1
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• pp.1-9
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• 1996

The edible natural pigments extracted from plant organs become steadly popular to consumer because of those physiological functions desirable for food preservation and human health in recent years. There are a number of colored rice genotypes from light brown to blackish purple via reddish brown and purple. Some researchers reported their results on extraction recipes and identification of chemical structure of the pigments from the colored rice. The pigments extracted from colored rices can be largely divided into two types of anthocyanin and tannin pigments. Anthocyanin pigments are mainly contained in purple or blackish purple rice while tannin pigments are mainly contained in brown or reddish brown rice. Some brownish purple rices showed two peaks of tannin and anthocyanin pigments simultaneously. Purple rices showed better extraction of pigments in $0.1\%$ HCl-contained $80\%$ methanol or $0.5\%$ malic-acid-contained $80\%$ ethanol, while red rices revealed better extraction of pigments in $0.01\%$ citric-acid-contained $80\%$ ethanol. The anthocyanin pigments are generally unstable to heat, light and acidity of solution. The pigments extracted from colored rice can be preserved stably under the dark and cool(<$5^{\circ}C$) condition and at pH $2.0\~4.0$. The anthocyanin pigments of purple rice are mainly composed by cyanidin-3-glucoside (chrysanthemin). The other pigment fractions in purple rice were identified to peonidin-3-gluco-side, malvidin-3-galactoside(uliginosin) and cyanidin-3-ramnoglucoside(keracyanin). The pericarp coloration of purple rices is controlled by three complimentary genes C (anthocyanin), A(activator) and $Pl^{w}$(purple leaf) genes, while the red rices are expressed by complimentary interaction between Rc(basic substance of pigment) and Rd(distribution of pigment) genes or C and $Pl^{w}$ genes. Recently, the antioxidation and antimutagenic activity in main component of anthocyanin pigments extracted from colored rice were identified. The natural pigments from colored rice can be useful for beverages, cakes, ice scream, cosmetic and so on.

• Korean Journal of Community Nutrition
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• v.18 no.3
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• pp.257-268
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• 2013

The purpose of this study was to evaluate nutrient intake and meal variety with breakfast eating in Korean adolescents using data from the 2008-2009 National Health and Nutrition Examination Survey. The analysis included 1245 adolescents aged 12 to 18 years. The subjects were divided into two groups according to breakfast skipping (BS: breakfast skipping, n = 235, BE: breakfast eating, n = 1110). The BS group was significantly higher in its frequency of eating soda drinks, instant noodle, and ice cream than the BE group. The BS group consumed significantly lower quantities of plant calcium and plant protein per 1,000 kcal compared to the BE group. Also the intake of cereal and vegetables in the BS group was significantly lower than those in the BE group, however, the intake of beverage in the BS group was significantly higher than that in the BE group. The average number of foods of the BE and BS groups were 29.50 and 25.85, respectively and revealed a statistical significance (p < 0.0001). The snack intake and % energy from snack intake of the BS group were significantly higher than those of the BE group. Also, the fasting blood glucose concentrations were significantly higher in the BS group compared to the BE group. In conclusion, adolescents who skip breakfast may have lower meal variety and higher blood glucose concentrations. Therefore, in support of proper dietary management, it is necessary to promote and encourage breakfast eating.

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.875-884
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• 2009

We present three nuclear/hydrogen-related R&D activities being performed at KAIST: air-ingressed LOCA analysis code development, gas turbine analysis tool development, and hydrogen-production system analysis model development. The ICE numerical technique widely used for the safety analysis of water-reactors is successfully implemented into GAMMA, with which we solve the basic equations for continuity, momentum conservation, energy conservation of the gas mixture, and mass conservation of 6 species (He, N2, O2, CO, CO2, and H2O). GAMMA has been extensively validated using data from 14 test facilities. We developed a tool to predict the characteristics of HTGR helium turbines based on the throughflow calculation with a Newton-Raphson method that overcomes the weakness of the conventional method based on the successive iteration scheme. It is found that the current method reaches stable and quick convergence even under the off-normal condition with the same degree of accuracy. The dynamic equations for the distillation column of HI process are described with 4 material components involved in the HI process: H2O, HI, I2, H2. For the HI process we improved the Neumann model based on the NRTL (Non-Random Two-Liquid) model. The improved Neumann model predicted a total pressure with 8.6% maximum relative deviation from the data and 2.5% mean relative deviation, and liquid-liquid-separation with 9.52% maximum relative deviation from the data.

• Journal of Plant Biotechnology
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• v.5 no.2
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• pp.83-86
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• 2003

A reverse transcription polymerase chain reaction (RT-PCR) protocol was developed using two specific 22-mer primers located in coat protein gene of SPFMV. A 411 bp PCR-product was detected in virus infected plants as well as tissue culture raised sweet potato but not in healthy plants. For optimization of RT-PCR protocol, the optimum crude nucleic acid concentration, annealing temperature, primer concentration and numbers of PCR-cycle for maximum sensitivity and specificity were determined. The optimum condition for RT-PCR was as follows: RT-PCR reaction mixture was one-step mixture, containing 50 pmol of primer, 30 units of reverse transcriptase, 5 units of RNasin, and the crude nucleic acid extracts (200 ng). In RT-PCR, cDNA was synthesized at $42^{\circ}C$ for 45 min before a quick incubation on ice after pre-denaturation at $95^{\circ}C$ for 5 min. The PCR reaction was carried out for 40 cycles at $96^{\circ}C$ for 30 see, $63^{\circ}C$ for 30 sec, $72^{\circ}C$ for 1 min, and finally at $72^{\circ}C$ for 10 min. The viral origin of the amplified product was confirmed by sequencing, with the sequence obtained having $95-98\%$ homology with published sequence data for SPFMV. The benefits of this RT-PCR based detection of SPFMV would be simple, rapid and specific.

• The Korean Journal of Quaternary Research
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• v.19 no.2
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• pp.55-58
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• 2005

A 120-cm core recovered from Lake Hovsgol, the northern Mongolia provides evidence for climate variability since the Marine Isotope Stage 3, representing a sharp lithological change. The lowermost part of the core consists of diatom-barren calcareous silty clay without coarse sands, framboidal pyrite, and biogenic components deposited during the MIS 3. Following the last glacial maximum, in-situ moss is included in the sediments, as lake-level was retreated by cold and dry environment with low precipitation. The AMS radiocarbon ages of the plant fragments match a marked lithologic boundary between 14,060 and 14,325 $^{14}C$ yr BP. The contents of coarse sands abruptly increase, indicating probably wind-derived sandy dust or coarse grains contributed from floating icebergs. And abundant framboidal pyrite grains were deposited in an anoxic environment, as reflected by high accumulation of organic matters at a low lake stand. During the deglaciation, quantities of coarse sands, ostracod, shell fragments, framboidal pyrite, and diatom markedly varies by regional and global scale climate regimes. Some allochthonous coarse sands were probably ice-rafted debris derived from floating icebergs. A rapid increase in diatom productivity probably marked the onset of Bolling-Allerod warming. Subsequent high concentration of framboidal pyrite probably represents a dry and cold condition, such as Younger Drays events. Consistent warm period with high precipitation at Holocene is documented by diatomaceous clayey ooze without framboidal pyrite, coarse sands, and ostracod.

• Journal of the Korean Society of Food Culture
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• v.28 no.3
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• pp.213-233
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• 2013

During the late Chosun Dynasty, famine was the main cause of climate ecological background, such as frequent floods and droughts, the Little Ice Age (小氷期), and epidemic. In addition, it influenced the social and cultural background, such as failure toprovide Yiangbeop (移秧法), breakout of war and revolt, loss of farming cattle, grain consumption due to brewing, the concentration of wealth, and tenacity of shamanism. "Limwongyungjeji" "Injeji" of the last part had been written about the famine; wild plants to raw, dried, or dried powder, or processed pharmaceutical goods. Grain couldbe replaced in more than 330 types of famine relief food and recipes; 170 species of vegetables, 34 species of vegetation, and 33 kinds of fruit - the botanic foods were mainstream. Edible parts of these plant foods are those of 14 kinds: 175 species of leaves, 113 species of sprouts, 99 kinds of buds, and other fruits, roots, stems, flowers, etc. The recipe (poaching, salting, and oil-marinated) was written 186 times or forsoup, raw, and boiled.

• Proceedings of the Korean Quaternary Association Conference
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• 2005.10a
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• pp.34-39
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• 2005

A 120-cm core recovered from Lake Hovsgol, the northern Mongolia provides evidence for climate variability since the Marine Isotope Stage 3, representing a sharp lithological change. The lowermost part of the core consists of diatom-barren calcareous silty clay without coarse sands, framboidal pyrite, and biogenic components deposited during the MIS 3. Following the last glacial maximum, in-situ moss is included in the sediments, as lake-level was retreated by cold and dry environment with low precipitation. The AMS radiocarbon ages of the plant fragments match a marked lithologic boundary between 14,060 and 14,325 $^{14}C$ yr BP. The contents of coarse sands abruptly increase, indicating probably wind-derived sandy dust or coarse grains contributed from floating icebergs. And abundant framboidal pyrite grains were deposited in an anoxic environment, as reflected by high accumulation of organic matters at a low lake stand. During the deglaciation, quantities of coarse sands, ostracod, shell fragments, framboidal pyrite, and diatom markedly varies by regional and global scale climate regimes. Some allochthonous coarse sands were probably ice-rafted debris derived from floating icebergs. A rapid increase in diatom productivity probably marked the onset of Bolling-Allerodwarming. Subsequent high concentration of framboidal pyrite probably represents a dry and cold condition, such as Younger Drays events. Consistent warm period with high precipitation at Holocene is documented by diatomaceous clayey ooze without framboidal pyrite, coarse sands, and ostracod.

• YAKHAK HOEJI
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• v.1 no.1
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• pp.1-2
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• 1948

The finely powdered entire harbs of Polygala japonica Houttuyn, a drug known as Yong Shin-Cho in Korea, were boiled with methanol and from the filtered extract the methanol was distilled off under diminished pressure and the aqueous solution of the residue was evaporated to dryness after being mixed with ignited magnesia. The dried mass was boiled with absolute alcohol, the filtered clear liquid was evaporated to a small volume and the precipitate Saponin produced by mixing with ether was filtered off. When the filtrate was again evaporated to the thickness of a syrup and allowed to cool for a few days in an ice box, crystalls were separated out in about 5% yield, which formed colorless columns, M. P. 142.deg., from methanol and had the formula $C_{6}$ $H_{12}$ $O_{5}$. On heating it with acetic acid anhybride and sodium acetate, its tetraacetyl derivative $C_{6}$ $H_{8}$ $O_{5}$(C $H_{3}$CO)$_{4}$ was obtained and which formed colorless needles, M. P. 62-5.deg., from ethanol. Their melting points, results of elementar analysis and other characteristics agreed with that of Polygalitol and its derivative. Finally they were proved to be identical with Polygalitol and its derivative, respectively, through determination of mixed melting points with the samples. Polygalitol was isolated from several plants of genus polugala e. g. P. amara, P. vulgaris, P. teunifolia, P. senega etc. The authors added to them another instance of identifying Polygalitol from the plant of genus polygala.olygala.

• Journal of the Korean Solar Energy Society
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• v.40 no.4
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• pp.23-33
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• 2020

The loss in photovoltaic power due to hailstorms has been highlighted as a major issue in the sustained growth of the PV power plant industry. This study investigates the safety of a solar module by conducting a numerical analysis of a hail test according to the IEC 61215 standard. Our study aims to elucidate the detailed behavior between the ice and solar modules and the micro-cracks forming on solar modules during hailstorms. To analyze the impact of hail, we used the ANSYS AUTODYN software to evaluate the impact characteristics on a solar module with different front glass thicknesses. The simulations show that a solar module with a glass thickness of 4.0 mm results in excellent durability against hail. The results indicate the feasibility of using simulations to analyze and predict micro-cracks on solar modules tailored to various conditions, which can be used to develop new solar modules.