• Ocean and Polar Research
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• v.33 no.spc3
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• pp.349-358
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• 2011

In order to ascertain latitudinal variation of lipid contents and compositions in copepods, we collected warm water copepod species (Euchaeta sp. and Pleuromamma spp.) from four different regions from low (sub-tropical) to mid (temperate) latitudes in the Northwest Pacific Ocean. Total lipid contents of Pleuromamma spp. were about 11 $ug{\cdot}ind^{-1}$ with little latitudinal variation, whereas Euchaeta sp. showed slightly higher lipid content (20 $ug{\cdot}ind^{-1}$) than Pleuromamma spp. with latitudinal gradient (low at subtropic and high at temperate). Wax esters, known as the major storage lipid classes, were found to be the dominant lipid classes (accounting for more than 35% of total lipids) in Euchaeta sp., whereas in Pleuromamma spp., phospholipids, known as cellular membrane components, were the dominant lipid classes. However, the exception was specimens from warm pool region exhibiting dominance in storage of lipids as a form of triacylglycerols. Among fatty acids, polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA : 22:6(n-3)) (about 35% of total fatty acids), were most abundant in Euchaeta sp., while saturated fatty acids (SAFA), specially hexadecanoic acid (16:0) (about 30% of total fatty acids), were most abundant in Pleuromamma spp.. Among the neutral fraction of lipids, phytol, originated from the side chain of chlorophyll, was found in all samples which generally indicate active copepods feeding on algae. While only trace amounts of short-chain fatty alcohols were found in Pleuromamma spp., significant amounts of fatty alcohols were found in Euchaeta sp.. Particularly, significant amounts of long chain monounsaturated fatty alcohols (20:1 and 22:1), generally found in cold water species, were found in Euchaeta sp. from low latitudes. The latitudinal variation of trophic lipid markers in these copepods could be significantly related with in-situ food availability and species-specific diet preference. The result of this study suggests that the lipid contents and compositions in copepods may not only indicate their nutritional condition and feeding ecology but also provide insight into species-specific living strategies under different environmental conditions (i.e. water temperature, food availability).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.171-180
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• 2002

The temporal and spatial distributions of phosphorus have been investigated in the Gomso Bay, Korea. TP, PIP, TOP and DIP in sediment were found 548.8mg P kg$^{-1}$ , 426.1mg P kg$^{-1}$ , 122.6mg P kg$^{-1}$ , and 0.217mg P kg$^{-1}$ , respectively with a decreasing order of PIP>TOP>DIP. Any temporal or spatial trend has not been found on the distribution of TP in the sediment, except the high TP values near the mouth of Julpo-chun. We found seasonal patterns high TOP(28.90% of TP) and low TIP(71.10% of TP) in August, but low TOP(15.63% of TP) and high TIP(84.38% of TP) in November. There were three times higher DIP concentration in August than in November. Such case is probably not only due to the enhanced supply of DIP directly from the decomposition of organic matter from overlying water in summer, but also the released phosphate from the adsorbed particulate matter such as PIP under the low pH and Eh conditions at the subsurface layers of the sediment induced by the active microbial respiration of increased organic materials in summer. Primarily, the source of phosphorous from municipal sewage strongly influenced the early stage of the distribution of all the phosphorous in the Gomso tidal flat. Notwithstanding, through the processes of diagenesis in sediment, water temperature and organic contents probably functioned as the key parameters to control the temporal distributions of TOP, TIP and DIP in the Gomso tidal flat.

• Resources Recycling
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• v.19 no.6
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• pp.43-50
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• 2010

The crisis of energy gives rise to the growing concerns over continuing uncertainty in the energy market. Under these circumstances, there are also increasing interests on coals. In particular, Low Rank Coal (LRC) is receiving gradual attentions from green industry. But due to is high moisture content range from 30 - 60%, drying process has to be preceded before being utilized as power plant. In this study drying kinetics of LRC is induced by using a fixed-bed reactor. The drying kinetics was evaluated in from of the particle size, the inlet gas temperature, the drying time, the gas velocity, and the LID ratio. The consideration of the reynold's number was taken for correction of gas velocity, particle size and LID was taken for correction of reactor diameter, packing height of coal. As being seen as characteristic of drying coal, it can be found that fixed-bed reactor can contributed to active drying of free water. In this sense, it could be considered that phase boundary reaction is appropriate mechanism.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.2
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• pp.135-141
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• 2019

Internet of thing becomes more active, many sensor devices are increasing. Sensors can use network wired network or use mobile communication network. From the viewpoint of the transmission rate, the mobile communication network can be roughly divided into two types of high-speed communication and low-speed communication. In the case of hundreds of millions of sensors in the mobile communication network, resources are wasted to use high-speed communication. Communication is required to reduce the transmission rate and appropriately allocate resources without wasting such resources. As the Internet of Thing has been activated, Narrowband Internet of Thing(NB-IoT), which is one of the low-power technologies in recent mobile communications, is in the spotlight from various companies. Currently, it can be seen that only NB-IoT or other low power consumption communication has the potential to be able to connect to the Internet with rapidly increasing sensor devices. In this paper, we designed and implemented a heater controller using Huawei NB-IoT communication Module, a server that collects controller information, and an application that allows default settings for devices. The main function of this system is to collect temperature and heater status and give it to the server, control the heater from the server, and set parameters for the heater to operate automatically. The system can be applied to places where wired communication is not established, such as road information, smart agriculture, and small reservoirs as well as heaters.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1605-1613
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• 2023

The physical properties of the ocean interior are determined by temperature and salinity. To observe them, we rely on satellite observations for broad regions of oceans. However, the satellite for salinity measurement, Soil Moisture Active Passive (SMAP), has low temporal and spatial resolutions; thus, more is needed to resolve the fast-changing coastal environment. To overcome these limitations, the algorithm to use the Geostationary Ocean Color Imager-II (GOCI-II) of the Geo-Kompsat-2B (GK-2B) was developed as the inputs for a Multi-layer Perceptron Neural Network (MPNN). The result shows that coefficient of determination (R²), root mean square error (RMSE), and relative root mean square error (RRMSE) between GOCI-II based sea surface salinity (SSS) (GOCI-II SSS) and SMAP was 0.94, 0.58 psu, and 1.87%, respectively. Furthermore, the spatial variation of GOCI-II SSS was also very uniform, with over 0.8 of R² and less than 1 psu of RMSE. In addition, GOCI-II SSS was also compared with SSS of Ieodo Ocean Research Station (I-ORS), suggesting that the result was slightly low, which was further analyzed for the following reasons. We further illustrated the valuable information of high spatial and temporal variation of GOCI-II SSS to analyze SSS variation by the 11th typhoon, Hinnamnor, in 2022. We used the mean and standard deviation (STD) of one day of GOCI-II SSS, revealing the high spatial and temporal changes. Thus, this study will shed light on the research for monitoring the highly changing marine environment.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.265.2-265.2
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• 2016

Oxide thin film transistors (TFTs) have attracted considerable interest for gate diver and pixel switching devices of the active matrix (AM) liquid crystal display (LCD) and organic light emitting diode (OLED) display because of their high field effect mobility, transparency in visible light region, and low temperature processing below $300^{\circ}C$. Recently, oxide TFTs with polycrystalline In-Ga-O(IGO) channel layer reported by Ebata. et. al. showed a amazing field effect mobility of $39.1cm^2/Vs$. The reason having high field effect mobility of IGO TFTs is because $In_2O_3$ has a bixbyite structure in which linear chains of edge sharing InO6 octahedral are isotropic. In this work, we investigated the characteristics and the effects of oxygen partial pressure significantly changed the IGO thin-films and IGO TFTs transfer characteristics. IGO thin-film were fabricated by rf-magnetron sputtering with different oxygen partial pressure ($O_2/(Ar+O_2)$, $Po_2$)ratios. IGO thin film Varies depending on the oxygen partial pressure of 0.1%, 1%, 3%, 5%, 10% have been some significant changes in the electrical characteristics. Also the IGO TFTs VTH value conspicuously shifted in the positive direction, from -8 to 11V as the $Po_2$ increased from 1% to 10%. At $Po_2$ was 5%, IGO TFTs showed a high drain current on/off ratio of ${\sim}10^8$, a field-effect mobility of $84cm^2/Vs$, a threshold voltage of 1.5V, and a subthreshold slpe(SS) of 0.2V/decade from log(IDS) vs VGS.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.3-9
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• 2009

Although Active matrix organic light emitting diode (AMOLED) display has a better image quality in terms of viewing angle, contrast ratio, and response time than liquid crystal displays (LCDs), it still has some critical issues such as lifetime, residual images, and brightness non-uniformity due to non-uniformity in electrical characteristics of driving TFTs and IR drops on supplied power line. Among them, we improved irrecoverable residual images of AMOLED displays which is mainly related to the hysteresis characteristics of driving TFTs. We consider four kinds of surface treatment conditions before gate oxide deposition for improving hysteresis characteristics. We can reduce the hysteresis level of p-channel TFT to 0.23 V, interface trap states between the poly-Si layer and gate insulator to $3.11{\times}10^{11}cm^{-2}$, and output current variation of p-channel TFT to 3.65 % through the surface treatment using ultraviolet light and H2 plasma. Therefore, the recoverable residual image problem of AMOLED displays can be improved by surface treatment using ultraviolet light and $H_2$ plasma.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.208.2-208.2
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• 2015

최근 산화물 반도체에 대한 연구가 활발하게 이루어지고 있다. 비정질 산화물 반도체인 In-Ga-Zn-O(IGZO)는 기존의 비정질 실리콘에 비해 공정 단가가 낮으며 넓은 밴드 갭으로 인한 투명성을 가지고 있고, 저온 공정이 가능하여 다양한 기판에 적용이 가능하다. 반도체의 공정 과정에서 열처리는 소자의 특성 개선을 위해 필요하다. 일반적인 열처리 방법으로 furnace 열처리 방식이 주로 이용된다. 그러나 furnace 열처리는 시간이 오래 걸리며 일반적으로 고온에서 이루어지기 때문에 최근 연구되고 있는 유리나 플라스틱, 종이 기판을 이용한 소자의 경우 기판이 손상을 받는 단점이 있다. 이러한 단점들을 극복하기 위하여 저온 공정인 마이크로웨이브를 이용한 열처리 방식이 제안되었다. 마이크로웨이브 열처리 기술은 소자에 에너지를 직접적으로 전달하기 때문에 기존의 다른 열처리 방식들과 비교하여 에너지 전달 효율이 높다. 또한 짧은 공정 시간으로 공정 단가를 절감하고 대량생산이 가능한 장점을 가지고 있으며, 저온의 열처리로 기판의 손상이 없기 때문에 기판의 종류에 국한되지 않은 공정이 가능할 수 있을 것으로 기대된다. 따라서 본 연구에서는 마이크로웨이브 열처리가 소자의 전기적 특성 개선에 미치는 영향을 확인하였다. 제작된 IGZO 박막 트렌지스터는 p-type bulk silicon 위에 thermal SiO2 산화막이 100 nm 형성된 기판을 사용하였다. RCA 클리닝을 진행한 후 RF sputter를 사용하여 In-Ga-Zn-O (1:1:1) 을 70 nm 증착하였다. 이후에 Photo-lithography 공정을 통하여 active 영역을 형성하였고, 전기적 특성 평가가 용이한 junctionless 트랜지스터 구조로 제작하였다. 후속 열처리 방식으로 마이크로웨이브 열처리를 1000 W에서 2분간 실시하였다. 그리고 기존 열처리 방식과의 비교를 위해 furnace를 이용하여 N2 가스 분위기에서 $600^{\circ}C$의 온도로 30분 동안 열처리를 실시하였다. 그 결과, 마이크로웨이브 열처리를 한 소자의 경우 기존의 furnace 열처리 소자와 비교하여 우수한 전기적 특성을 나타내는 것을 확인하였다. 따라서 마이크로웨이브를 이용한 열처리 공정은 향후 저온 공정을 요구하는 소자 공정에 활용될 수 있을 것으로 기대된다.

• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.291-295
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• 2007

This study was conducted to investigate the optimum shading material of rain shelter in Panax ginseng C.A. Meyer. Results obtained from our experiment can be summarized as follows. From photosynthetically active radiation (PAR) as shade materials on sunny day, temperature under rain shelter was low in comparison with that under polyethylene net. It was ranged from 3 to $5^{\circ}C$ Survival rate of 3,4, and 5 year-old ginsengs under shade materials of rain shelter was lower than that under polyethylene net. Root fresh weight in ginseng grown under rain shelter was increased into about 5.0g in 3 year-old, 10g in 4 year-old and 8g in 5 year-old ginsengs. From investigating root grade of 3, 4, and 5 year-old ginsengs, we confirmed that rain shelter was more effective than the other as shading materials. Root size of 3, 4, 5 year-old ginsengs grown under rain shelter is distributed in bigger size than that grown under polyethylene net. Also, in the case of saponin contents, the ginseng grown under the shade material of rain shelter was higher than that under polyethylene net.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.233-238
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• 2014

In case of the slender mass concrete like attached wall, retaining wall and bridge tower, the low heat cement and the control joint are mainly used for thermal cracking control. However, even if these cracking control methods are considered, it is impossible to control thermal cracks perfectly, because the external restraint is largely in these mass concrete. Because these cracks occurring in slender mass concrete members almost penetrate concrete member, the special cracking control is demanded in these mass concretes. The vertical pipe cooling method improving existing pipe cooling method was developed for the active thermal cracking control of slender mass concrete, and applied at the field attached wall. In results, the maximum temperature dropped more than $10^{\circ}C$ by vertical pipe cooling method, and the cracks decreased about more than 50%.