• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.189-194
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• 2005

The evaporation heat transfer and pressure drop of $CO_2$ in a small diameter tube was investigated experimentally. The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator(test section). The test section was made of a horizontal stainless steel tube with the inner diameter of 4.57 mm, and length of 4 m. The experiments were conducted at mass flux of 200 to 700 $kg/m^2s$, saturation temperature of $0^{\circ}C$ to $20^{\circ}C$, and heat flux of 10 to 20 $kW/m^2$ . The test results showed the evaporation heat transfer of $CO_2$ has great effect on more nucleate boiling than convective boiling. The evaporation heat transfer coefficients of $CO_2$ are highly dependent on the vapor quality, heat flux and saturation temperature. The evaporation pressure drop of C02 are highly dependent on the mass flux. In comparison with test results and existing correlations, correlations failed to predict the evaporation heat transfer coefficient and pressure drop of $CO_2$, therefore, it is necessary to develop reliable and accurate predictions determining the evaporation heat transfer coefficient and friction pressure drop of $CO_2$ in a horizontal tube.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.262-267
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• 2005

The evaporation heat transfer coefficient of $CO_2$ in a horizontal round tube was investigated experimentally. The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator(test section). The test section was made of a horizontal stainless steel tube with the inner diameter of 7.75 mm, and length of 5 m. The experiments were conducted at mass flux of 200 to 500 $kg/m^2s$, saturation temperature of $-5^{\circ}C$ to $5^{\circ}C$, and heat flux of 10 to 40 $kW/m^2$. The test results showed the evaporation heat transfer of $CO_2$ has great effect on more nucleate boiling than convective boiling. The evaporation heat transfer coefficients of $CO_2$ are highly dependent on the vapor quality, heat flux and saturation temperature. In comparison with teat results and existing correlations, correlations failed to predict the evaporation heat transfer coefficient of $CO_2$, therefore, it is necessary to develop reliable and accurate predictions determining the evaporation heat transfer coefficient of $CO_2$ in a horizontal tube.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.835-843
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• 2008

We have fabricated the source-drain electrodes for OTFTs by screen printing method and manufactured Ag pastes as conductive paste. To obtain excellent conductivity and screen-printability of Ag pastes, the dispersion characteristics of Ag pastes prepared from two types of acryl resins with different molecular structures and Ag powder treated with caprylic acid, triethanol amine and dodecane thiol as surfactant respectively were investigated. The Ag pastes containing Ag powder treated with dodecane thiol having thiol as anchor group or AA4123 with carboxyl group(COOH) of hydrophilic group as binder resin exhibited excellent dispersity. But, Ag pastes(CA-41, TA-41, DT-41) prepared from AA4123 fabricated the insulating layer since the strong interaction between surface of Ag powder and carboxyl group(COOH) of AA4123 interfered with the formation of conduction path among Ag powders. The viscosity behavior of Ag pastes exhibited shear-thinning flow in the high shear rate range and the pastes with bad dispersion characteristic demonstrated higher shear-thinning index than those with good dispersity due to the weak flocculated network structure. The output curve of OTFT device with a channel length of 107 ${\mu}m$ using screen-printed S-D electrodes from DT-30 showed good saturation behavior and no significant contact resistance. And this device exhibited a saturation mobility of $4.0{\times}10^{-3}$ $cm^2/Vs$, on/off current ratio of about $10^5$ and a threshold voltage of about 0.7 V.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.657-662
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• 2006

The present paper dealt with an experimental study of condensation heat transfer coefficients with refrigerant R-22, R-407C and R-410A, and was focused on pressure gradient and heat transfer coefficient in horizontal tube-in-tube heat exchangers using inner diameter of 4 mm, 3 mm and 2 mm in a 16.91 mm tube and length of 3,000 mm. Experiments were performed at inlet saturation temperature of 35 to $45^{\circ}C$ and mass flux ranges from 200 to $600 kg/m^2s$. The pressure gradient with inner tube diameter of 4.0 mm is higher 2.5 times than that of 8.0 mm. In tube-in-tube HEX, the pressure gradient of R-410A were lower than those of R-22 and R-407C. The condensation heat transfer coefficients increased with mass flux increase, but they decreased with saturation temperature increased. Condensation heat transfer coefficients of R-410A were a little higher than those of R-22 and R-407C. The condensation heat transfer coefficients of tube-in-tube HEX were about 40% higher than those of double tube HEX.

• 한국수산과학회지
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• 제27권1호
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• pp.69-82
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• 1994

해조류를 첨가한 사료가 조피볼락의 어린 시기에 미치는 생리적 효과를 알아보기 위하여, 전장 $2.99{\pm}0.23\;cm$, 체중 $1.03{\pm}0.18\;g$의 인공종묘에게 미역분말을 각각 $3\%,\;5\%,\;7\%$ 첨가한 사료와 비첨가 사료를 주면서 140일간 사육하여 전장$18.52{\pm}1.07\;cm$, 체중 $120.64{\pm}19.32\;g$이 될 때까지의 어체 성장, 생존율, 체조성, 혈액조성을 서로 비교하고, 저산소 및 기아 내성에 관한 생리활성을 연구하였다. 1. 전장과 체중의 성장은 $5\%$의 미역 첨가시 가장 좋았으며, $3\%,\;7\%$, 대조구인 $0\%$ 순이었다. 2. 실험구별 사료효율은 $3\%,\;5\%,\;7\%,\;0\%$구의 순으로 높았으며, 생존율은 $7\%,\;5\%,\;3\%,\;0\%$구 순이었다. 3. 사육종료시의 체조성에 있어 등 근육의 수분, 조단백질, 조지방 및 조회분은 실험구별로 큰 차이를 보이지 않았으나, 전내장의 조지방 함량은 미역 첨가구가 대조구에 비해 많았다. 4. 미역 첨가구는 $0\%$구 보다 헤마토크릿트값이 크고, 평균적혈구수도 많았다. 5. 실험종료시 사료별 어체의 저산소내성은 미역 첨가구가 대조구에 비해 강했다. 6. 사육실험 종료후 31일간의 기아 실험에서 미역 첨가구의 어체중은 대조구에 비해 적게 감소하였다. 7. 조피볼락 양식에서 사료에 미역을 첨가해 줄 경우, 그 비율은 $5\%$가 가장 적합하며 어체의 생리조건에 좋은 영향을 줄 수 있는 것으로 판단되었다.

• Journal of Ginseng Research
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• 제26권2호
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• pp.85-88
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• 2002

고려인삼을 순계분리 육성하여 품종 등록한 인삼 신품종의 광도, 온도별 광합성 능력과 광합성 관련 형질인 기공, 엽록소, 비엽중 및 지상하부 형질들을 조사한 결과를 요약하면 다음과 같다. 신품종 및 자경종의 광포화점은 15,000 lux내외였고, 광합성 최적온도는 2$0^{\circ}C$였다. 광합성 능은 연풍>천풍>고풍>자경종 순으로 연풍이 가장 높았다. 호흡속도는 모든 품종이 온도가 높아짐에 따라 빨라지는 경향이었으며, 타품종에 비해 호흡량이 높았다. 비엽중은 천풍>고풍>연풍>자경종 순서로 높았고, 엽록소 함량은 품종간 차이가 근소하였다. 단위면적당 기공수는 연풍이 69.2개로 타계통의 40~47개보다 많았고, 기공의 크기는 연풍이 26.5 $\mu\textrm{m}$ 타품종 37.5~38.8 $\mu\textrm{m}$보다 적었다. 연풍은 경수가 1.8개, 장염수가 7.7개, 소염수가 41.0개, 엽면적이 12.3 dm$_2$로 타 품종보다 지상부의 생육이 양호하였다. 근중은 연풍>천풍>고풍>자경종 순으로 무거웠고, 동장은 천풍과 고풍이 각각 6.5, 6.8 cm로 자경종 5.6 cm보다 길어서 체형이 양호하였으나 연풍은 동장이 4.4 cm로 짧았다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.847-853
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• 2016

Applications of Si have been increasingly exploited and extended to More-Moore, More-than-Moore, and beyond-CMOS approaches. Ge is regarded as one of the supplements for Si owing to its higher carrier mobilities and peculiar band structure, facilitating both advanced and optical applications. As an emerging metal-oxide device, the junctionless field-effect transistor (JLFET) has drawn considerable attention because of its simple process, less performance fluctuation, and stronger immunity against short-channel effects due to the absence of anisotype junctions. In this study, we investigated lateral field scalability, which is equivalent to channel-length scaling, in Si and Ge JLFETs. Through this, we can determine the usability of Si CMOS and hypothesize its replacement by Ge. For simulations with high accuracy, we performed rigorous modeling for ${\mu}_n$ and ${\mu}_p$ of Ge, which has seldom been reported. Although Ge has much higher ${\mu}_n$ and ${\mu}_p$ than Si, its saturation velocity ($v_{sat}$) is a more determining factor for maximum $I_{on}$. Thus, there is still room for pushing More-Moore technology because Si and Ge have a slight difference in $v_{sat}$. We compared both p- and n-type JLFETs in terms of $I_{on}$, $I_{off}$, $I_{on}/I_{off}$, and swing with the same channel doping and channel length/thickness. $I_{on}/I_{off}$ is inherently low for Ge but is invariant with $V_{DS}$. It is estimated that More-Moore approach can be further driven if Si is mounted on a JLFET until Ge has a strong possibility to replace Si for both p- and n-type devices for ultra-low-power applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.121-122
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• 2006

Recently, poly-Si TFT-LCD starts to be mass produced using excimer laser annealing (ELA) poly-Si. The main reason for this is the good quality poly-Si and large area uniformity. We report the influence of channel length and width on poly-Si TITs performance. Transfer characteristics of n-channel poly-Si thin film transistors fabricated on polycrystalline silicon (poly-Si) thin film transistors (TFTs) with various channel lengths and widths of $2-30{\mu}m$ has been investigated. In this paper, we analyzed the data of n-type TFTs. We studied threshold voltage ($V_{TH}$), on/off current ratio ($I_{ON}/I_{OFF}$), saturation current (I_{DSAT}$), and transconductance ($g_m$) of n-channel poly-Si thin film transistors with various channel lengths and widths.

• 한국ITS학회 논문지
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• 제10권6호
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• pp.108-117
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• 2011

서울시는 2001년부터 실시간 신호제어시스템(COSMOS)를 운영하고 있으며, 도시부 신호교차로의 신호운영 자료인 포화도 및 대기길이의 산출을 위하여 검지기를 설치해 차량으로부터 기초자료를 습득하고 있다. 현재 가장 보편적으로 사용하는 것은 유도성 루프검지기로 도로의 노면에 매설하는 방식이라 유지 보수가 용이하지 않고 비용이 많이 드는 단점이 있다. 또한 대기길이의 산정시 검지기를 통과하는 차량의 속도만으로 계산해야하기 때문에 속도측정 오차 발생시에 대기길이의 값에 영향을 미치게 된다. 제안하는 알고리즘은 카메라, 센서 및 이미지처리 장치와 같은 추가적인 장치 없이, VANETs(Vehicular Ad-hoc Networks)의 차량 간의 통신을 이용하고 각 방향별 그룹을 설정하여 교차로에서 원활한 교통 흐름을 가능케 하는 실시간 교통신호 제어 시스템을 제안한다. 본 연구에서 제안한 알고리즘은 GLD(Green Light District) Simulator를 기반으로 단일교차로 모델에서 AJWT(Average Junction Waiting Time)와 TQL(Total Queue Length) 에 대해서 확인하였으며 그 결과를 무작위(Random) 제어방식 및 최상우선(Best first) 제어방식과 비교하여 더 나은 결과를 보였다. 향후 VANETs를 활용한 실시간 제어방법이 보편화 될 경우 무선 통신기술을 이용한 교차로의 교통제어기술을 제안한 본 연구는 그 활용가치가 높을 것으로 판단된다.

• 한국농공학회논문집
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• 제56권4호
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• pp.77-82
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• 2014

In Korea, length of irrigation and drain canal is about 98,638 km. In the case of 2011, dredging on the irrigation and drain canal was 7,288 km about 3,290,483 $m^3$, cost of dredging was about 5.6 billion won and cost of dredging increases every year. (Korea Rural Community Corporation, 2013). In the case of land reclamation, the problem of cross-contamination due to leachate after landfill is expected, causing saturation of the landfill site, or complaints of landfill local residents, a number of problems. The ocean landfill is possible if the items of 14 types as defined in the Sea Pollution Prevention Law contained in sediment soil, such as chromium. In terms of cost and labor, it is need to develop a technology utilizing a processing method reasonable sediments for irrigation and drainage canal. The objective of this study was to analyze the characteristics of the sediment deposited on the irrigation and drain canal. it is to provide basic data for the scheme that can be efficiently recycled sediment deposited on the irrigation and drain canal.