• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.2
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• pp.160-164
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• 1999

Subsurface environments, including the intermediate vadose zone and aquifers, may be contributing to increased atmospheric concentrations of $N_2$O. Denitrification appears to be the major source of $N_2$O in the subsurface environment. In the intermediate vadose zone, the level of denitrifying activity is dependent on the soil morphology, particularly stratified layers within the soil profile, which impede water and solute movement and create conditions favorable for denitrification. Movement of organic C from the soil surface appears to support denitrifying activity by providing an energy source and increasing the consumption of $O_2$. Denitrirication and $N_2$O production have been observed in aquifers but appear to be of greatest significance in shallow unconfined aquifers. The lack of organic C, N $O_2$, or anaerobiosis is often a limiting factor for activity but seems to be site specific. The presence of denitrifying bacteria does not appear to be a major limitation, based on published results, but the ubiquity of denitrifiers in subsurface environments needs to be confirmed. The fate of the $N_2$O produced in subsurface environments is unknown. Transport of $N_2$O by up ward diffusion, by outgassing at contacts with surface waters, and by ground water use need to be quantified to determine the contribution to atmospheric $N_2$O. Contamination of subsurface environment with N $O_3$$^{ }$ and organics has the potential for increasing the contribution to atmospheric $N_2$O by enhancing denitrification .

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.949-958
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• 2008

This study was carried out to examine the association of age, nutrient intake, alcohol drinking and smoking on serum lipid and apolipoprotein levels in 100 healthy adults (54 males and 46 females). The serum total cholesterol, low density lipoprotein cholesterol (LDL-C) (p<0.05), apolipoprotein B (Apo B) levels, LDL-C:high density lipoprotein cholesterol (HDL-C) ratio, Apo B:apolipoprotein(Apo A-I) ratio and atherogenic index (AI) (p<0.001) were significantly higher in males than females, but HDL-cholesterol level was significantly lower (p<0.01) in males than females. The plasma ascorbic acid concentration had no difference in both genders. Most of nutrient intakes except Ca, vitamin A and vitamin $B_2$ were higher than RI (Recommended intake) in both males and females. The meal frequency per day was significantly higher (p<0.01) in males than females, while meal speed, the heaviest meal, meal quantity and meal regularity had no significant differences. The rates of drinking and smoking were significantly higher (p<0.01) in males (59.3%, 37.2%) than females (17.3%, 6.9%). The age was positively correlated with triglyceride level in males (p<0.05), and with total cholesterol (p<0.001), LDL-cholesterol (p<0.001), Apo B (p<0.01), LDL-C:HDL-C ratio (p<0.01), Apo B:Apo A-I ratio (p<0.05) and AI (p<0.01) in females. The levels of serum lipid and apolipoprotein were more correlated with protein intake than other macronutrient intakes in males, while those in females were more correlated energy, carbohydrate and lipid intakes than protein intake. The effect of drinking on serum lipid and apolipoprotein levels was bigger in males than females, while the effect of smoking on those was bigger in females than males. The plasma ascorbic acid concentration was positively correlated with HDL-cholesterol (p<0.05), Apo A-I levels (p<0.001), whereas negatively correlated with Apo B:Apo A-I ratio (p<0.05) in males. And that was positively correlated with HDL-cholesterol (p<0.05) in females. These results suggest that moderate macronutrient intake, less alcohol consumption and non-smoking were necessary to maintain healthy lipid profile with aging in adults.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.704-711
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• 2011

Traditionally, mistletoes have been used as immunostimulant for the management of certain diseases such as cancer with high profile immune depleting potentials. In order to examine the safety of the 20 kGy irradiated cold water extract powder of mistletoes, we performed a 90-day repeated-dose toxicity study with ICR mice. The mice were treated with daily doses of the 20 kGy irradiated cold water extract powder of mistletoes by gavage at 0, 20, 100, and 500 mg/kg/day for 90 consecutive days. We recorded clinical signs of toxicity, body weight, organ weights, histological changes in target organs, hematology, and clinical blood chemistry analysis data for all mice. There were no significant changes in body and organ weights during the experimental period. The hematological analysis and clinical blood chemistry data revealed no toxic effects from the 20 kGy irradiated cold water extract powder of mistletoes. Pathologically, neither gross abnormalities nor histopathological changes were observed between the control and treated mice of both sexes. Collectively, these data suggest that the 20 kGy irradiated cold water extract powder of mistletoes have a high margin of safety.

• Progress in Medical Physics
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• v.23 no.4
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• pp.234-238
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• 2012

A tumor on the eyelid is often treated using a high-energy electron beam, with a metallic eye shield inserted between the eyelid and the eyeball to preserve the patient's sight. Pretreatment quality assurance of the inner eyelid dose on the metallic shield requires a very small dosimetry tool. For enhanced accuracy, a flexible device fitting the curved interface between the eyelid and the shield is also required. The radiochromic film is the best candidate for this device. To measure the doses along the curved interface and small area, a 3-mm-wide strip of EBT2 film was inserted between the phantom eyelid and the shield. After irradiation with 6 MeV electron beams, the film was evaluated for the dose profile. An acrylic eye shield of the same size as the real eye shield was machined, and CT images free from metal artifacts were obtained. Monte Carlo simulation was performed on the CT images, taking into account eye shield material, such as tungsten, aluminum, and steel. The film-based interface dose distribution agreed with the MC calculation within 2.1%. In the small (millimeter scale) and curved region, radiochromic film dosimetry promises a satisfactory result with easy handling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.417-427
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• 2016

This paper is the first investigation of the steady flow characteristics of an SI engine with a semi-wedge combustion chamber as a function of the port shape. For this purpose, the planar velocity profiles were measured at the 1.75B position by particle image velocimetry. The flow patterns were examined with both a straight and a helical port. Two swirls were observed up to 4 mm valve lift with the straight port and up to 2 mm with the helical one; however, only one swirl was present after these lifts. The flow characteristics changed suddenly between 4 and 5 mm lift in the straight port; on the other hand, the change with lift was gradual with the helical port - the transition points between flow regimes were different with the port shapes. In addition, the centers of the swirls were relatively far from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B, regardless the shape. The eccentricity values with the straight port were especially high - over 0.5 for all lifts. Finally, real velocities were found to be much lower than those predicted by the assumption of ISM evaluation, with the profiles differing qualitatively as well.

• Journal of the Korean Electrochemical Society
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• v.2 no.4
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• pp.213-217
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• 1999

The electrochemical characteristics of two distinct adsorption sites of H at the polycrystalline Pt/0.2 M LiOH aqueous electrolyte interface have been studied using the phase-shift method. At the forward and backward scans, the under-potentially deposited H (WD H) peak occurs on the cyclic voltammogram. The transition region on the phase-shift profile or the Langmuir adsorption isotherm occurs at ca. -0.66 to -0.96 V vs. SCE. At the transition region (ca. -0.66 to -0.96 V vs. SCE), the equilibrium constant (K) for H adsorption transits from 18.5 to $4.0\times10^{-5}$ and vice versa. Similarly, the standard free energy $({\Delta}G_{ads})$ of H adsorption transits from -7.2 to 25.1kJ/mol and vice versa. The under and over-potentially deposited H (UPD H and OPD H) on the poly-Pt surface act as two distinguishable electroadsorbed H species. An exothermic reaction occurs at the UPD H range. Both the UPD H peak and the transition region are attributed to the two distinct adsorption sites of the UPD H and OPD H on the poly-Pt surface.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6A
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• pp.585-593
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• 2010

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure local location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of sinks. Most existing geographic routing protocols merely assume that source nodes are aware of the locations of sinks. How can source nodes get the locations of sinks was not addressed in detail. In this paper, we propose a sink location service via circle path for geographic routing in wireless sensor networks. In this scheme, a sink sends a Sink Location Announcement (SLA) message along a circle path, and a source node sends a Sink Location Query (SLQ) message along a straight path that certainly passes through the circle path. By this way we can guarantee the SLQ path and SLA path have at least one crossing point. The node located on the crossing point of the two paths informs the source node the sink location. This procedure can correctly work in any irregular profile sensor networks such as network that has holes or irregular shape by some rules. Simulation results show that our protocol is superior to other protocols in terms of energy consumption and control overhead.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.151-158
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• 2010

Camelina sativa L., known as popular names "gold-of-pleasure" or "false flax" is an alternative oilseed crop that can be grown under different climatic and soil conditions. Up to date, however, the genomic information of Camelina has not been studied in detail. Therefore, a cDNA library was constructed and characterized from young leaves. The constructed cDNA library incorporated of 1334 cDNA clones and the size of the insertion fragments average was 736 base pair. We generated a total of 1269 high-quality expressed sequence tags (ESTs) sequences. The result of cluster analysis of EST sequences showed that the number of unigene was 851. According to subsequent analysis, the 476 (55.9%) unigenes were highly homologous to known function genes and the other 375 (44.1%) unigenes were unknown. Remaining 63 (7.4%) unigenes had no homology with any other peptide in NCBI database, indicating that these seemed to be novel genes expressed in leaves of Camelina. The database-matched ESTs were further classified into 17 categories according to their functional annotation. The most abundant of categories were "protein with binding function or cofactor requirement (27%)", "metabolism (11%)", "subcellular localization (11%)", "cellular transport, transport facilities and transport routes (7%)", "energy (6%)", "regulation of metabolism and protein function (6%)". Our result in this study provides an overview of mRNA expression profile and a basal genetic information of Camelina as an oilseed crop.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.220-220
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• 2013

Surface-normal transmission electro-absorption modulator (EAM) are attractive for high-definition (HD) three-dimensional (3D) imaging application due to its features such as small system volume and simple epitaxial structure [1,2]. However, EAM in order to be used for HD 3D imaging system requires uniform modulation performance over large area. To achieve highly uniform modulation performance of EAM at the operating wavelength of 850 nm, it is extremely important to remove the GaAs substrate over large area since GaAs material has high absorption coefficient below 870 nm which corresponds to band-edge energy of GaAs (1.424 eV). In this study, we propose and experimentally demonstrate a transmission EAM in which highly selective backside etching methods which include lapping, dry etching and wet etching is carried out to remove the GaAs substrate for achieving highly uniform modulation performance. First, lapping process on GaAs substrate was carried out for different lapping speeds (5 rpm, 7 rpm, 10 rpm) and the thickness was measured over different areas of surface. For a lapping speed of 5 rpm, a highly uniform surface over a large area ($2{\times}1\;mm^2$) was obtained. Second, optimization of inductive coupled plasma-reactive ion etching (ICP-RIE) was carried out to achieve anisotropy and high etch rate. The dry etching carried out using a gas mixture of SiCl4 and Ar, each having a flow rate of 10 sccm and 40 sccm, respectively with an RF power of 50 W, ICP power of 400 W and chamber pressure of 2 mTorr was the optimum etching condition. Last, the rest of GaAs substrate was successfully removed by highly selective backside wet etching with pH adjusted solution of citric acid and hydrogen peroxide. Citric acid/hydrogen peroxide etching solution having a volume ratio of 5:1 was the best etching condition which provides not only high selectivity of 235:1 between GaAs and AlAs but also good etching profile [3]. The fabricated transmission EAM array have an amplitude modulation of more than 50% at the bias voltage of -9 V and maintains high uniformity of >90% over large area ($2{\times}1\;mm^2$). These results show that the fabricated transmission EAM with substrate removed is an excellent candidate to be used as an optical shutter for HD 3D imaging application.

• Journal of the Korean Society of Radiology
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• v.4 no.2
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• pp.21-25
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• 2010

Recently, various semiconductor compounds as radiation detection material have been researched for a diagnostic x-ray detector application. In this paper, we have fabricated the CdS detecton sensor that has good photosensitivity and high x-ray absorption efficiency among other semiconductor compounds, and evaluated the application feasibility by investigating the detection properties about energy range of diagnostic x-ray generator. We have fabricated the line voltage selector(LCV) for a signal acquisition and quantities of CdS sensor, and designed the voltage detection circuit and rectifying circuit. Also, we have used a relative relation algorithm according to x-ray exposure condition, and fabricated the interface board with DAC controller. Performance evaluation was investigated by data processing using ANOVA program from voltage profile characteristics according to resistive change obtained by a tube voltage, tube current, and exposure time that is a exposure condition of x-ray generator. From experimental results, an error rates were reduced according to increasing of a tube voltage and tube current, and a good properties of 6%(at 90 kVp) and 0.4%(at 320 mA) ere showed. and coefficient of determination was 0.98 with relative relation of 1:1. The error rate according to x-ray exposure time showed exponential reduction because of delayed response velocity of CdS material, and the error rate has 2.3% at 320 msec. Finally, the error rate according to x-ray dose is below 10%, and a high relative relation was showed with coefficient of determination of 0.9898.