• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.224-227
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• 2013

본 연구에서는 S/D이 n+/n+로 구성된 CNT-MOSFETs, 금속으로 이루어진 SB-CNTFETs와 p+/n+로 구성된 CNT-TFETs에 대한 각각의 $I_d-V_g$ 특성과 포텐셜 프로파일을 확인하였다. 그리고 각 소자의 특성 및 특징을 연구하고, 이 중에서 BTB에 가장 큰 영향을 받는 CNT-TFETs의 특성을 $V_{DS}$, 분자 비대칭성과 $T_{ox}$에 따른 특성 변화를 연구하였다. 그 결과 예상과 다르게 오히려 작은 $V_{DS}$와 큰 $E_g$을 가질 때, 향상된 SS를 가진다는 것을 확인 할 수 있었다. 특히, (7,0) CNT-TFETs에서 비록 $I_d$는 작지만, SS를 57mV/dec까지 개선할 수 있었다. 또한, $T_{ox}$를 얇게 하면, 비록 60 mV/dec 이하의 결과는 보여주지 못했지만, SS와 Ion 모두 개선할 수 있음을 확인할 수 있었다.

• Tunnel and Underground Space
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• v.29 no.5
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• pp.318-331
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• 2019

A three-dimensional(3D) equivalent continuum modeling was performed to analyze hydraulic behavior of rock mass considering discontinuities by using DFN model and smeared fracture model. DFN model was generated by FLAC3D and smeared fracture model was applied by using FISH functions, which is built-in functions in FLAC3D, for equivalent continuum model of fractured rock mass. Comparative analysis with 3DEC, which is for discontinuum analysis, was conducted to verify reliability of equivalent continuum analysis by using FLAC3D. Similar results of hydraulic analysis under the same conditions could be achieved. Equivalent continuum analysis of fractured rock mass by using DFN model was implemented to compare with existing analytical methods for inflow into the tunnel.

• Journal of the Korea Convergence Society
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• v.11 no.4
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• pp.343-350
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• 2020

This study was intended to use the Inertia Sensor Units(IMU) for the national women's handball team to quantify movements for a total of 16 domestic or international practice games over five months and to identify the efficiency of training and differences in movements by position. A total of 15 players were participated excluding goalkeepers. The results are as follows. Player Load came in order of Wing>Back>Pivot and high in international games. Change of Direction(CoD) were found to have the most Pivot at low intensity, while middle and high intensity were the most in the Back. There have been a lot of low and middle intensity CoD in International games. Low-intensity acceleration(ACC) and deceleration(DEC) were found to have the most Pivot, while middle & high intensity ACC and DEC had the most Back. There have been many low and middle intensity ACC and low, middle and high intensity DEC in international games. There were many middle and high intensity jumps in Back and Wing, but there were no differences in the types of games.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.4
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• pp.238-244
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• 1995

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survial or regrowth yield. Forage rape(Brassica napus L.) was sown on Sep. 1, 1994. Experimental plots were divided into three replicates under 6 different cutting dates(l0 days interval from Oct. 15 to Dec. 4). Field-grown palnts were sampled on the each cutting date and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. On the before wintering, dry matter yields were 152, 274, 500, 718, 776 and 981 kg/lOa, respectively, from the cutting date on Oct. 15, Oct. 25, Nov. 4, Nov. 14, Nov. 24, and Dec. 4. Cmde protein yield significantly increased as cutting date was later until Nov. 14, thereafter a significant increase did not occured. Nitrogen and starch contents per plant significnatly increased as the cutting date was later. The increasing rate of starch was greatly higher than that of nitrogen. On the wintering period, nitrogen reserves in mts were 85.3, 68.8, 47.6, 28.3, 44.3, and 55.3 mglplant, and starch reserve were 11 1.3, 75.3, 39.3, 19.6, 26.4 and 34.6 mglplant, respectively, in the plots cut on Oct. 15, Oct. 25, Nov. 4, Nov. 14, Nov. 24, and Dec. 4. It showed that carbohydrate reserves were much highly utilized than nitrogen reserves during wintering period. The rates of winter survival were 91, 83, 46, 22, 35 and 43% and regrowth yields were 692, 545, 316, 84, 127 and 140 kgD.M/lOa, respectively, in each plots. The highly significant correlation (p<0.01) between the level of organic reserves and the rate of winter survival or regrowth yield were obtained.

• Tunnel and Underground Space
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• v.24 no.6
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• pp.440-448
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• 2014

Hydraulic fracturing technique has been applied in various fields in order to improve the recovery of energy resources such as gas, oil and geothermal energy and research about finding out hydraulic fracturing mechanism and application has been steadily proceeded. In this study, for effective hydraulic fracturing, a scale modeling was progressed to simulate similarly with the actual site. In order to analyze the development aspect of surface crack initiation pressure during hydraulic fracturing followed by different conditions, the number of guide holes hydraulic fracturing test was carried out by setting up a hydraulic fracturing test equipment. Also, through the result, we tried to derive reliable results by comparing and analyzing the value of numerical modeling which is obtained based on the physical properties and mechanical properties with 3DEC, a three-dimensional discrete element method program. As a result, it is considered possible to generate effective crack using the guide hole.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.473-478
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• 2017

In this study, the guanidine compound, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was impregnated to three kinds of silica to prepare $CO_2$ adsorbents, and the $CO_2$ adsorption and physicochemical properties of the resulting adsorbents were investigated. The TBD amount of impregnation was changed and its effect on adsorption capacity and characteristics were studied. The physicochemical properties of TBD-impregnated silica were evaluated with $N_2$ adsorption/desorption, FT-IR, elemental analysis, and thermogravimetric analysis. The TBD-impregnated silica lowered the surface area and pore volume, and the increased impregnation amount of TBD made them further decrease. When TBD was 6 mmol/g, the $CO_2$ adsorption capacity was the highest at 7.3 wt%, and the adsorption capacity decreased due to the blocking phenomenon when the TBD amount increased.

• Tunnel and Underground Space
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• v.26 no.5
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• pp.409-417
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• 2016

The shale gas is emerging as one of the oil and gas resources which can replace the traditional oil and gas resources. As the shale layer where the shale gas is deposited has low permeability, the hydrofracturing method is required to improve the productivity. This study is designed to conduct the laboratory hydrofracturing test on the samples which are modeled after the drilling hole having the general drilling hole and spiral groove. And compare the initial fracturing pressure and fluid contact between them in order to the result of the hydrofracturing depending on the shape of the drilling hole. In addition, the results were compared with the numerical modeling values from 3DEC and they were also compared with the data from the advance researches. It was found from the study that rather than the contact area of the high pressures water, the force concentration depending on the form of guide hole was more effective in the hydrofracturing.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.96-104
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• 2023

Synergistically increased oxygen evolution reaction (OER) of manganese oxide (MnO₂) catalyst is introduced with surface-modified halloysite nanotube (Fe₃O₄-HNTs) structure. The flake shaped MnO₂ catalyst is attached on the nanotube template (Fe₃O₄-HNTs) by series of wet chemical and hydrothermal method. The strong interaction between MnO₂ and Fe₃O₄-HNTs maximized active surface area and inter-connectivity for festinate charge transfer reaction for OER. The synergistical effect between Fe₃O₄ layer and MnO₂ catalyst enhance the Mn³⁺/Mn⁴⁺ ratio by partial replacement of Mn ions with Fe. The relatively increased Mn³⁺/Mn⁴⁺ ratio on MnO₂@FHNTs induced 𝜎^* orbital (e_g) occupation close to single electron, improving the OER performances. The MnO₂@FHNTs catalyst exhibited the reduced overpotential of 0.42 V (E vs. RHE) at 10 mA/cm² and Tafel slope of (99 mV/dec), compared with that of MnO₂ with unmodified HNTs (0.65 V, 219 mV/dec) and pristine MnO₂ (0.53 V, 205 mV/dec). The present study provides simple and innovative method to fabricate nano fiberized OER catalyst for a broad application of energy conversion and storage systems.

• Journal of Fisheries and Marine Sciences Education
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• v.9 no.2
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• pp.149-166
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• 1997

This thesis is studied by means of operation diary of the factory ship GAECHEOG in the Sea of Okhotsk and the Sea of Bering from Jul. 1993 to Dec. 1996, We summarize these results as follows : 1. The factory ship GAECHEOG equipped trawl winch able to haul raw fish 700M/T per day and cargo winch able to unload manufactured goods 900M/T. The crews consist of 290~330 persons. 2. Factory machineries equipped surimi making plant able to process about 150M/T per day and fish meal plant able to manufacture about 70M/T per day. 3. The fishing ground from June to Nov. was the western Bering sea lying in the eastern Kamchaka peninsula and from Dec. to May, the fishing period to gather roe of a Pollack, was the Sea of Ohotsk lying in the western Kamchaka peninsula. 4. The buying catch of fish per each voyage from Dec. to May, the fishing period gathering Pollack-roe, was about 17,000~33,000M/T and from Jul. to Oct., the fishing period gathering non Pollack-roe, was about 10,000~21,000 M/T. 5. Raw fish was the most about 33,000M/T of the 2nd voyage in 1994 and was the least about 8,300M/T of the 1st voyage in 1993. Other voyages were about 13,000~18,000M/T. 6. The Pollack buying from Jul. to Nov. in the Bering sea was 5~7 fishes for one row in pan and body length about 40~50cm, and from Dec. to May in the Sea of Ohotsk was 6~8 fishes for one row in pan and body length about 37~45cm. 7. Surimi production in the 2nd voyage in 1994 was the most about 7,300 M/T, in the 1st voyage in 1993 was the least 1,900M/T and in other voyages was about 2,500~3,800M/T. The extraction rate of surimi goods for raw fish was about 17.4~26.5%. 8. Fish meal production in the 2nd voyage in 1994 was the most about 2,300 M/T, in the 1st voyage in 1993 was the least about 780M/T and in other voyages was about 1,100~1,700M/T. The extraction rate of fish meal goods for raw fish was about 7.3~10.7%. 9. Pollack-roe production was very much from Jan. to Apr. and was about 380~700M/T per each voyage. The extraction rate of Pollack-roe for raw fish was about 1.2~4.9%.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.224-231
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• 2000

The exfoliation of graphite (layer) was progressed due to the irreversible insertion of PC molecules between graphene layers, when propylene carbonate (PC) solvent was used as the organic solvents. The problem could be mitigated by the replacement of PC by ethylene carbonate (EC). But, the freezing point of EC-based electrolyte increased due to the high freezing point of $EC(36.2^{\circ}C)$. Therefore, EC+PC mixed electrolyte is expected as a good organic electrolyte for lithium ion battery. The EC-based organic electrolyte containing PC within pertinent quantity can be expected to have high molar conductivity and reduced exfoliation of graphite layer. The dielectric constant and molar conductivity of $LiPF_6/PC+EC+DEC$ electrolyte was investigated with a variation in the PC content. The electrochemical properties of carbon electrode in the electrolyte were also investigated. Molar conductivity and dielectric constant increased linearly by increasing the PC volume fraction in the electrolyte. The results of charge-discharge test for carbon/electrolyte/Li cell indicated that the initial irreversible specific capacity(IIC) of MCMB-6-28s and MPCF3000 decreased by the addition of $0.83 vol\%$ of PC, but increased with PC content over than $0.83 vol\%$. In the case of MPCF3000 and PCG100 having less than $10 vol\%$ PC, IIC was lower than 50 mAh/g. The discharge specific capacities varied with carbon material, but did not vary with PC content in the electrolyte.