• Journal of Electrochemical Science and Technology
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• 제1권2호
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• pp.121-126
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• 2010

An amperometric ascorbic acid selective sensor utilizing the transfer reaction of proton liberated from the dissociation of ascorbic acid in aqueous solution across an elliptic micro-hole water/organic gel interface is demonstrated. This redox inactive sensing platform offers an alternative way for the detection of ascorbic acid to avoid a fouling effect which is one of the major concerns in redox based sensing systems. The detection principle is simply measuring the current change with respect to the assisted transfer of protons by a proton selective ionophore (e.g., ETH 1778) across the micro-hole interface between the water and the polyvinylchloride-2-nitrophenyloctylether gel phase. The assisted transfer reaction of protons generated from ascorbic acid across the polarized micro-hole interface was first characterized using cyclic voltammetry. An improved sensitivity for the quantitative analysis of ascorbic acid was achieved using differential pulse stripping voltammetry with a linear response ranging from 1 to $100\;{\mu}M$ concentrations of ascorbic acid. As a demonstration, the developed sensor was applied for analyzing the content of vitamin-C in different types of commercial pharmaceutical tablets and syrups, and a satisfactory recovery from these samples were also obtained.

• 한국분무공학회지
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• 제17권1호
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• pp.14-19
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• 2012

The present study conducts experimental investigation on spreading and deposition characteristics of a $4.3{\mu}l$ de-ionized (DI) water droplet impacting upon aluminum (Al 6061) flat and textured surfaces. The micro-textured surface consisted the micro-hole arrays (hole diameter: $125{\mu}m$, hole depth: $125{\mu}m$) fabricated by the conventional micro-computer numerical control (${\mu}$-CNC) milling machine process. We examined the surface effect of texture area fraction ${\varphi}_s$ ranging from 0 to 0.57 and impact velocity of droplet ranging from 0.40 m/s to 1.45 m/s on spreading and deposition characteristics from captured images. We used a high-speed camera to capture sequential images for investigate spreading characteristics and the image sensor to capture image of final equilibrium deposition droplet for analyze spreading diameter and contact angle. We found that the deposition droplet on textured surfaces have different wetting states. When the impact velocity is low, the non-wetting state partially exists, whereas over 0.64 m/s of impact velocity, totally wetting state is more prominent due to the increase kinetic energy of impinging droplet.

• 한국자동차공학회논문집
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• 제1권1호
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• pp.32-40
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• 1993

Flow fields in model engine cooling passages are studied numerically by using TURBO-3D program, a finite volume based 3-D turbulent flow program adopting a general body fitted coordinate system. The effects of exit position on mass flow rate at each gasket hole are examined for a model cooling passage in order to understand the flow distribution inside the water jacket. The results of the present study can be applied to the design of high performance, high reliability engine.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기설비전문위원
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• pp.85-87
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• 2008

In this paper, we manufactured waterproof outlet that use silicon packing know-how. Developed outlet is waterproof packing on pins of the plug insertion hole and electric wire insertion hole. Therefore, outlet body internal furnace water can prevent that is flowed in. Temperature anomaly can use in back large outer wall, restaurant exposed easily to moisture, bathroom, laundry, a laboratory and science room, auditorium, etc. That is estimate that contribute on courtesy call of electricity calamity.

• 대한기계학회논문집A
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• 제40권4호
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• pp.337-342
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• 2016

스퍼드캔(spudcan)은 잭업리그(jack-up rig)의 다리 하단에 장착되며, 해저면에 구조물을 안정적으로 지지하여 구조물의 전복사고를 방지하기 위한 장치이다. 표층이 모래 층일 때는 침투(penetration) 시에 스퍼드캔을 안정적으로 삽입하기 위해서, 그리고 점토 층일 때는 회수(extraction) 시에 원활하게 뽑아 올리기 위해서 스퍼드캔에는 물 분사장치가 장착되어 있다. 본 연구에서는 물 분사장치를 위한 배관라인용 홀의 형상을 최적화하기 위해 크게 타원형과 원형 두 가지 형상을 설정하였다. 해석을 위해 대상 Site 는 멕시코만(Gulf of Mexico)로 선정하였고 대상 플랫폼은 해상풍력발전기설치선(WTIV)을 선택하였다. 상용프로그램인 ANSYS Workbench 를 사용하여 최적설계를 진행하였다. 본 연구결과는 다양한 해양구조물의 홀 형상설계에 적용될 수 있다.

• 대한토목학회논문집
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• 제3권3호
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• pp.87-94
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• 1983

지하유류비축공동(地下油類備蓄空洞)의 성패(成敗)는 공동상부(空洞上部)에 충분(充分)한 수두(水頭)를 유지(維持)하여 공동주위(空洞周圍)의 수밀성(水密性)을 보장(保障)하는 데 있다. 공동상부(空洞上部)에 충분(充分)한 수두(水頭)가 유지(維持)되면 저장(貯藏)된 유류(油類)의 Gas가 누출(漏出)되지 않으며, 인접공동(隣接空洞)이 비어있을 때에도 이곳으로 유류(油類)는 이동(移動)되지 않는다. 본(本) 연구(硏究)에서는 전기상사모형실험(電氣相似模型實驗)을 통(通)하여 수평(水平) 및 수직(垂直) Water Curtain을 설치(設置)하여 Gas 누출(漏出)과 유류이동(油類移動)을 방지(防止)하려 할 때 효과적(効果的)인 Water Curtain의 위치(位置), 인접공동간격(隣接空洞間隔) Water Curtain 수두(水頭), Bore-hole 간격 등이 검토(檢討)되었다. 연구결과(硏究結果) 공동(空洞)의 간격(間隔)이 좁으면 수직(垂直) Water Curtain은 꼭 설치(設置)되어야 하며, 공동간격(空洞間隔)이 공동(空洞) 높이의 2배 이상 커지면 수직(垂直) Water Curtain은 필요(必要)없다는 것이 입증(立證)되었고 유류이동(油類移動)을 방지(防止)하는데 필요(必要)한 수평(水平) 및 수직(垂直) Water Curtain의 위치(位置), Water Curtain 수두(水頭), Bore hole 간격 등이 도표(圖表)로 주어졌다.

• 대한토목학회논문집
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• 제42권2호
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• pp.197-208
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• 2022

암반층이 얕은 깊이에서 출현하는 국내 지층 조건과 지하 공간의 활용도 증가로 인해서, 발파에 의한 굴착은 여전히 이용되고 있다. 발파 천공 이후에 존재하는 물이 있는 조건에서 실시되는 표준 발파는 폭굉압력 감소, 일정 장약량 사용, 디커플링과 같은 기술적인 어려움이 있다. 하지만, 기존의 표준 발파 공법을 대체할 만한 공법이 없는 실정이다. 본 논문에서는 건공화 펌프 시스템을 이용하여, 천공 내부에 존재하는 물을 제거하는 건공화 ANFO (Ammonium Nitrate Fuel Oil) 발파와 발파 성능의 비교를 위해서 추가적으로 표준 발파를 수행하였다. 각각의 발파 공법에서 계측된 진동 속도 데이터들과 환산거리의 함수로 이루어진 경험적인 발파진동 추정식을 이용하여, 최소제곱법에 의한 선형회귀분석을 실시하고, 궁극적으로 발파 성능을 정량적으로 분석하였다. 그 결과, 건공화 ANFO 발파에서 진동 감쇠가 더 크게 발생하고, 암반 파쇄에 더 많은 에너지를 소비하여, 더 가까운 거리에서 진동 허용 기준을 만족하는 진동 속도를 보였다. 또한, 표준 발파의 발파 진동 영향권이 건공화 ANFO 발파보다 더 멀리 있고, 발파 패턴의 범위가 더 넓은 것으로 나타났다. 본 연구에서 수행된 현장 발파 실험 결과로부터, 건공화 ANFO 발파 공법의 발파 성능이 효율적임을 확인하였다.

• 상하수도학회지
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• 제12권1호
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• pp.88-95
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• 1998

The Electron/Hole Pair is generated when the Activation Energy produces by Ultraviolet Ray illumination to the Semiconductor. And $OH^-$ ion produces by Water Photo-Cleavage reacts with Positive Hole. As a result, OH Radical acting as strong oxidant is generated and then Photocatalytic Oxidation Reaction occurs. The Photocatalytic Oxidation can oxidize the chlorophenol to Chloride and Carbon Dioxide easier, safer and shorter than conventional Water Treatment Process With the same degree of chlorination, the $Cl^-$ ion at para (C4) position is most easily replaced by the OH radical. And then, the blocking effect of $OH^-$ ion between the $Cl^-$ ions and $Cl^-$ ions at symmetrical location is easily replaced by the OH radical. For mono-, di-, tri-chlorophenols, there is no obvious difference in decomposition rate, decomposition efficiency and completeness of the decomposition reaction except for 2,3-dichloropheno, 2,4,5-, 2,3,4-trichlorophenol. The decomposition efficiency is higher than 75% and completeness of the decomposition reaction is higher than 70%. Therefore, continuous flow photocatalytic reactor is promising process to remove the chlorinated aromatic compounds which is more toxic than non-chlorinated aromatic compound.

• 설비공학논문집
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• 제18권4호
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• pp.370-376
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• 2006

The paper concerns an experimental study of fully developed laminar flow of a Newtonian and non-Newtonian liquid in concentric annuli with combined bulk axial flow and inner cylinder rotation. Pressure losses and skin friction coefficients have been measured for Newtonian fluid, water and non-Newtonian fluids, 0.2% aqueous of sodium carboxymethyl cellulose (CMC) and 5% bentonite solutions, when the inner cylinder rotates at the speed of $0{\sim}500$ rpm. The influences of rotation, radius ratio and working fluid on the annular flow field are investigated. And the new correlations among the skin friction coefficient, the Reynolds number and the Rossby number are presented with reasonable limits of accuracy in laminar flow regime.

• Current Optics and Photonics
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• 제5권3호
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• pp.238-242
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• 2021

In this paper, we present an in line plastic-optical-fiber (POF) temperature sensor based on intensity modulation. The in line POF temperature sensor is composed of a POF, including an in-fiber micro hole filled with reversible thermochromic material, the transmittance of which depends on temperature. The reversible thermochromic material was cobalt chloride/polyvinyl butyral gel. A cobalt chloride solution of concentration 30.8 mM was formulated using 10% water/90% ethanol (v/v) solution, and gelled by dissolving polyvinyl butyral in this solution. Four types of in line POF sensors, with in line micro holes of four different diameters, were fabricated to measure temperature in the range of 25 to 75 ℃. The output optical power of all of these in line POF temperature sensors was inversely proportional to the temperature; the relation between output power and temperature was approximately linear, and the sensitivity was proportional to the diameter of the in-fiber micro hole. The experimental results indicate that an in line POF sensor can be used effectively for measuring moderate temperatures.