• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.415-419
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• 2018

This paper predicts and measures the C/N ratio of a beacon signal transmitted from geostationary orbit satellite KorSat 5A ($113^{\circ}E$) at a ground station located in Kimpo. Based on the ground stations, we compared the rain attenuation of the zone K of ITU-R and the rain attenuation which analyzed the domestic weather information. In ITU-R, the Korean rainfall characteristics are classified into zone K, but forecasting the rainfall intensity and attenuation of three adjacent cities based on the cumulative rainfall data per minute from 2013 to 2017. The calculation of rainfall path and attenuation is based on ITU-R recommendations. The change of the C/N according to the rainfall amount was confirmed through the 2 week satellite beacon signal C/N measurement. The predicted critical C/N was decreased to 12 dB at $A_{0.3}$. During the experiment, it was confirmed that it decreased up to 8 dB according to the concentrated rainfall.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.322-324
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• 2003

Leaf C:N ratio is a new factor in the field of biochemical inversion with hyperspectral data. Effects of common-used spectral transformations including log(R), log(1/R), 1/R, etc. from 400nm to 2490nm on its inversion are compared. Results show that their effects on statistical modeling are not apparent. Continuum removal is used on original reflectance in the range of 2030nm to 2220nm, in which exists an apparent absorption peak due to cellulose, lignin, protein, etc. The effect is distinctive and tends to improve the precision of C:N ratio inversion. Further, it is a robust and physically based transformation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.391-395
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• 2000

In this study, the temperature coefficient of resonant frequency(TC $F_{r}$), dielectric and piezoelectric properties of Pb[(S $b_{1}$2/N $b_{1}$2/)$_{0.0035}$-(M $n_{1}$3/N $b_{2}$3/)$_{0.0065}$-(Z $r_{x}$ $Ti_{1-x}$ )$_{0.90}$] $O_3$ceramics is investigated with Zr/Ti ratio. The dielectric constant and electromechanical coupling factor( $k_{p}$) showed the highest values of 1257, 0.562 respectively when the Zr/Ti ratio is 49.5/50.5. The mechanical quality factor( $Q_{m}$) is the lowest value of 713 when the Zr/Ti ratio is 49.5/50.5, and increased with the decrease of the Zr/Ti ratio. The temperature coefficient of resonant frequency(TC $F_{r}$) change abruptly at the morphotropic phase boundary(MPB), which is between the rhombohedral phase with highly negative TC $F_{r}$ of -106ppm/$^{\circ}C$ and the tetragonal phase with highly positive TC $F_{r}$ of +64pp $m^{\circ}C$ as Zr/Ti ratio changes from 50/50 to 49.5/50.5.50.5..5.50.5.5.

• Journal of Soil and Groundwater Environment
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• v.27 no.6
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• pp.47-57
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• 2022

A number of different methods have been used for modeling the sorption of volatile organic chlorinated compounds such as tetrachloroethylene/perchloroethylene (PCE). In this study, PCE was adsorbed in several natural sorbents, i.e., Pahokee peat, vermicompost, BionSoil^®, and natural soil, in the batch experiments. Several sorption models such as linear, Freundlich, solubility-normalized Freundlich model, and Polanyi-Manes model (PMM) were used to analyze sorption isotherms. The relationship between sorption model parameters, organic carbon content (f_oc), and elemental C/N ratio was studied. The organic carbon normalized partition coefficient values (log K_oc = 1.50-3.13) in four different sorbents were less than the logarithm of the octanol-water partition coefficient (log K_ow = 3.40) of PCE due to high organic carbon contents. The log K_oc decreased linearly with log f_oc and log C/N ratio, but increased linearly with log O/C, log H/C, and log (N+O)/C ratio. Both log K_F,oc or log K_F,oc decreased linearly with log f_oc (R² = 0.88-0.92) and log C/N ratio (R² = 0.57-0.76), but increased linearly with log (N+O)/C (R² = 0.93-0.95). The log q_max,oc decreased linearly as log f_oc and log C/N increased, whereas it increased with log O/C, log H/C and log (N+O)/C ratios. The log q_max,oc increased linearly with (N+O)/C indicating a strong dependence of q_max,oc on the polarity index. The results showed that PCE sorption behaviors were strongly correlated with the physicochemical properties of soil organic matter (SOM).

• The Korean Journal of Physiology
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• v.3 no.1
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• pp.19-28
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• 1969

Skin temperatures on 10 sites and rectal temperature at every 10 minutes, oxygen consumption at every 20 minutes were measured on 18 male subjects (ages between 14 and 47 years) after exposure to cold air at $15^{\circ}C$ for two hours in a climatic room. Total body fat measured by means of a skinfold method and ratio of body surface area (S) to body volume (V), S/V, were utilized as basis of observations. Surface area was calculated after DuBois equation and body volume was calculated by our original formula. In influencing on the heat loss from the body core to the cold environment, % fat showed inverse relations, whereas, S/V ratio showed direct relations. Thus these two factors acted antagonistically on the body heat loss. Local skin temperatures showed negative correlations with skinfold thickness on the same site, nemaly, on chest, r=-.567; on back, r=-.507; and on upper arm, r=-.353. The other 7 skin sites showed low correlations with % fat. Minimum mean weighted skin temperature (MWST) showed a negative correlation (r=-.443) with % fat, and showed no correlation with S/V ratio. Oxygen consumption in the cold air at $15^{\circ}C$ increased from the first measurement at 20 minutes after exposure and maintained the same increasing trend up to 120 minutes. ${\Delta}T_R$ was greater in tile lean subjects who showed a greater % change in oxygen consumption. The antagonistic actions of % fat and S/V ratio on the heat loss were manifested by observations as follows: minimum rectal temperature was higher In fat subjects (r=.600) and lower in subjects with a greater S/V ratio (=-.582), ${\Delta}T_R$ was smaller in fat subjects (r=-.738) and greater in subjects with a greater S/V ratio (r=.618). Temperature difference between body core and skin surface (minimum rectal temperature minus minimum MWST) showed a positive correlation with % fat (r=.600) and a negative correlation with S/V ratio (r=-.881). Decrease in the mean body temperature and heat debt, respectively, showed negative correlations with % fat and positive correlations with S/V ratio.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.415-423
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• 2018

The aim of this study was to evaluate the individual glucosinolate (GSL), total phenol, total flavonoid, and vitamin C content, and antioxidant activity under various light quality condition, mainly focusing on red (R) to far-red (FR) light ratios in three Brassica sprouts (radish, Chinese cabbage, and broccoli). Three R/FR ratio of 0.6, 1.3, and 2.0 were exposed to 5-day old sprouts for 48 h in a controlled environment, and the targeted phytochemical contents and antioxidant activities were compared with three separate control plot of dark, fluorescent, and red:blue 8:2 conditions. Total GSL content was highest in broccoli among the cultivars throughout the respective treatments, and increased with the increasing of R/FR ratio in the broccoli sprouts, while the content showed non-significant results in the Chinese cabbage sprouts. The progoitrin, a major GSL in Chinese Cabbage and broccoli, content decreased by upto 38% and 69%, respectively, with decreasing the R/FR ratio compared to the control plots (fluorescent, red:blue 8:2, and dark condition). The contents of phenol, flavonoid, and vitamin C were lowest in dark condition in all the three Brassica sprouts. The total phenol content and antioxidant activities increased with decreasing the R/FR ratio in all the Brassica sprouts, while total flavonoid and vitamin C content showed different patterns depending upon the Brassica sprouts. These results suggest that additional use of FR is expected to improve the functional quality of Brassica sprouts in different ways.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.2
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• pp.141-149
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• 2009

As the number of personal computers installed in vehicles increases, a touchpad often used in a labtop computer can be used for the control of an in-vehicle information system (IVIS). Using a touchpad to control the system allows the user to select among large amount of information with a single touch of dragging. For safety and convenience of a driver, the touchpad could be placed on a steering wheel. This research is designed to calculate the most efficient Control-Response Ratio (C/R ratio) for the menu interaction of a touchpad on a steering wheel. Since the menu pointer's rate of movement and proper C/R ratio is determined by the amount of selected information, the amount of displayed information and the movement of a menu pointer was chosen to be independent variables. The dependent variables are a user's preference and task completion time. Two factor full factorial within subject design was used 16 subjects. The investigation revealed that the amount of selected information increased with increasing C/R ratio. The movement of the pointer became slower as the amount of information increased. The best C/R ratio was calculated for each amount of information and preference regression of the user's preference was drawn accordingly. Through this research, the automobile interior designer can benefit from the guidelines suggested for the touchpad control.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.11a
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• pp.79-80
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• 2003

국내의 대부분 도시하천에 우점하여 나타나는 깔따구속(Chironomus)은 국내에 밝혀진 깔따구과(Chironomidae)중에서 가장 다양한 종다양성을 보이며 개체가 상대적으로 크고 사육이 용이하여 생태학, 독성학 및 분자유전학적 재료로 널리 쓰이고 있다. 그러나 깔따구속 각 종간의 성충 및 유충의 형태적 유사성으로 인하여 많은 분류학적 어려움을 안고 있다. 특히 국내에 분포하는 노랑털깔따구(C. flaviplumus)와 요시마쓰 깔따구(C. yoshimatsui)는 성충과 유충에 있어서 많은 변이가 나타나 여러 문헌에서 혼동되어 쓰이고 있는 실정이므로 그들의 분류가 시급한 실정이다. 본 연구에서는 전형적인 한국의 도시하천인 서울시 중랑천을 대상으로 그곳에 우점하는 장수깔따구(C. plumosus), 구슬등무늬깔따구(C. circumdatus), 등깔따구(C. dorsalis), 안개무늬깔따구(C. kiiensis), 요시마쯔깔따구의 형태적 유사성 및 차이점을 비교하였다. 채집된 요시마쯔깔따구는 배무늬 및 생식기 형태에서 다양한 변이를 보였으며, Wing length 2.77$\pm$0.17mm (2.53-2.94), Leg ratio(L.R.)가 1.60$\pm$0.05, Antenna ratio(A.R.) 2.84土0.10의 값을 나타냈다. 일부 개체는 A.R.이 3.35로 국내산 노랑털깔따구(A.R. 3.50$\pm$0.11, Ree & Kim, 1981)와 혼란될 수 있으나 이는 요시마쯔깔따구 군집내의 변이로 생각된다. 국내에 기록된 요시마쯔깔따구와 노랑털깔따구는 일본산 요시마쯔깔따구와 노랑털깔 따구가 A.R.값이 각각 3.1과 4.0(Sasa, 1978)으로 구별되는 것과 달리 A.R.에서 큰 차이가 나타나지 않고 배무늬 및 생식기 형태의 변이 폭이 크게 나타나므로 앞으로 전국적인 지역에 분포하는 상기 두 종의 개체군에 대한 비교 연구가 필요하다.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.318-323
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• 2014

In order to analyze the effect of maleic anhydride (MAH) content and styrene monomer (SM)/MAH mole ratio on reactive extrusion of maleic anhydride grafted random polypropylenes (MAH-g-rPP), MAH-g-rPPs were prepared by using a twin screw extruder. MAH contents were 0.5, 1.0, 3.0, and 5.0 phr and SM/initiator mole ratio was 0.0, 1.0, and 2.0. Dicumyl peroxide (DCP) was used as an initiator. The graft degree of MAH was confirmed by the existence of carbonyl group (C = O) stretching peak at $1700cm^{-1}$ from FT-IR spectrum. The degree of graft reaction increased up to 3.0 phr MAH and showed the optimum value at 1.0 SM/MAH mole ratio from the area ratio of C = O and C-H stretching peak. Thermal and crystallization properties of MAH-g-rPP and PP/MAH-g-rPP/pulp composites were investigated by DSC, TGA, XRD, and POM. There was a decrease in non-isothermal crystallization temperature of PP/MAH-g-PP/pulp composites. Based on tensile properties and SEM pictures for the fractured surface of PP/MAH-g-PP/pulp composites, MAH content of 1.0 wt% and SM/MAH mole ratio of 1.0 were the optimum formulation as the compatibilizer. The rheological properties of the composites were measured by dynamic Rheometer to compare the processability of the composites with and without compatibilizer. The power law index showed slightly low value at the composites with compatibilizer.

• Journal of Korea Foundry Society
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• v.25 no.1
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• pp.30-35
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• 2005

The structures and mechanical property of the unidirectionally solidified Al-Co eutectic alloy were investigated. Al-Co eutectic alloy was unidirectionally solidified with growth rates(R) between I cm/hr and 10 cm/hr in the induction furnace maintaining the thermal gradient (G) at solid-liquid interface, $32^{\circ}C$/cm. The eutectic microstructure was varied with the growth condition(G/R ratio). When the G/R ratio was larger than $8.5{\times}10^{3}^{\circ}C/cm^{2}/sec$, a lamellar structure was formed, But the G/R ratio was smaller than $8.5{\times}10^{3}^{\circ}C/cm^{2}/sec$, a colony structure was formed. It was found that the interlamellar spacing(${\lambda}$) was dependent on the growth rate(R) with the relationship, ${\lambda}^{2}{\cdot}R=constant$. The microhardness of this eutectic alloy increased with increase in the growth rate.