• Corrosion Science and Technology
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• 제16권6호
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• pp.273-277
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• 2017

Atmospheric corrosion is clearly the most noticeable of all corrosion processes. A tremendous amount of economic losses are caused by atmospheric corrosion. Thus, it is imperative to know the level of atmosphere's aggressiveness or in other words "corrosivity", before designing or planning any corrosion prevention strategy. In Singapore, corrosivity values were not recorded earlier though the process of measurement and recording was prevalent in other countries. With an aim of filling this gap, three test sites were setup at three locations in Singapore to represent marine, industrial and urban atmospheres or their mixtures. Subsequently, corrosivity readings were measured and recorded according to ISO 9223:2012 for the first time in Singapore. Salient atmospheric constituents or parameters like time of wetness (TOW), $Cl^-$, $SO_2$, $NO_2$, $O_3$, and $HNO_3$ were measured at all sites over a period of time to categorize corrosivity of particular atmosphere. The effect of the atmosphere on corrosion of steel, Cu, Al, and Zn has also been investigated and quantified. "Estimated" and "determined" corrosivities were quantified and compared according to ISO 9223 standard. The study data along with final corrosivity measurements will be presented and discussed in the present work.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.253-259
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• 2004

The Jeju Island in Korea is the clean area which the tradition culture is preserved locally well with the nature environment of Heaven's blessing. An air pollution is becoming recently serious problem as the industrial development is proceeded with the urbanization. This study investigates that the atmosphere environment at Jeju area influences on the metal corrosion. A study of the atmosphere corrosion for carbon steel, copper, zinc ana aluminium exposed on five test sites indoors and outdoors. Corrosion results are treated statistically and adjusted to a model previously proposed for carbon steel, copper, zinc and aluminium based on the influence of environmental parameters and main pollutants($SO_2$ and chlorides) on tire atmosphere corrosion of metals. Through this study, we try to set the standards atmosphere corrosion at Jeju Island.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.22-28
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• 2008

Friction stir welding(FSW) is an relatively new solid state joining process. A1606l-T6 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio and good corrosion resistance. This friction stir process(FSP) uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, etc., and tool pin profile playa major role in deciding FSP zone formation in A16061-T6 aluminium alloy. Tow different tool pin profiles have been used to fabricate the joints. The formation of friction stir processed zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the friction stir processed zone formation.

• 한국해양학회지
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• 제24권4호
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• pp.165-171
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• 1989

동물플랑크톤 시료의 변이 정도를 조사하기 위하여, 충남 연안역에서 서로 약 4km 떨어진 두 정점을 정하고, 각 정점에서 썰물에서 밀물까지의 주간 6시간 동안 NORPAC형 네트(직경 76cm, 망목 0.333mm)를 사용하여 매 시간마다 혹은 두 시간마다 동물플랑크톤을 채집하였으며, 매 채집시 3회씩의 반복 채집이 실시되었다. 동물플랑크톤의 주기적 수직이동에 의한 자료변이를 극소화하기 위하여 네트는 저층에서 표층까지 수직 인양되었다. 시료 채집일은 1989년 4월 5일과 6일이었다. 다섯 개 우점 분류군의 개체수 분포에 있어, 두 정점간 차이는 크게 두드러지지 않았으나, 각 정점에서 서로 다른 시간대에 얻어진 평균 개체수들은, 최대치가 최소치의 2.3-8.7배의 범위로 크게 변하였다. 그러나, 이들 서로 다른 시간대의 평균 개체수들은 통계적으로 95% 신뢰도에서 유의적 차이를 보이지 않았다. 이것은 매우 큰 분산 때문으로, patch의 영향이 해수의 이동 등과 관련, 시간에 따라 변하고 있음을 말해주는 것으로 여겨졌다. 반복 채집 시료간의 변이계수로 부터, 한번 채집에서 얻어진 개체수는 그 값의 50-200%에 있는 역시 한번 채집에서 얻어진 다른 수치와 통계적 유의성이 없을 것으로 판단되었다. 이러한 결과에서 시간별 채집 및 반복 채집의 필요성이 크게 인식되었다. 이로부터 서해 연안역에서의 적절한 채집 방법은, 연구목적, 해수 이동특성 등에 따라 결정되겠지만, 가능한 정점수를 줄이고 대신 각 정점에서 여러 차례, 반복 채집하는 것이 좋은 것으로 사료되었다.

• 한국안전학회지
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• 제31권5호
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• pp.28-34
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• 2016

When a electric power cable is installed in the air for newly or exchanged working, it is necessary at all time to hold a constant tension for an overhead power cable. And also a pendanted power cable is an extreme job to have work in a high sky. For this reason, the objective of this paper developments working robot for preventing disaster that tension of cable installed automatically power cable to hold a constant. So the working robot works at all the time two tasks for mobil and tension it come into a inference between two tasks, control is difficult. Control methode needs to suppress inference of two tasks. In this paper, for installation of overhead power cable, the scheme and control methode of working robot is presented. the robot work at a same time tow tasks that have hold a constant tension of the power cable and move a constant place while unfasten a winding cable at a drum on a chassis. Working robot consist of three parts with mobile system, tension system and control part. As it is applied the feedback/feedforward control, methode of hybrid control is established to suppress that interference come into between two tasks. The simulation programs is made out using models of mobil and tension system, and a proposed controllers. In accordance with simulation, the model of each systems is discussed to make out proper. And also parameters of controllers is selected a suitable value and the driving performance of robot is evaluated.

• 한국인쇄학회지
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• 제20권2호
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• pp.31-43
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• 2002

Screen printing is a stencil process whereby ink is transferred to the substrate through a stencil supported by a fine fabric mesh. Therefore screen had a tendency to distort and swell, as ink was deposited between the fibers, and were difficult to clean. The tow importance of stencil parameters that affect print quality are stencil thread diameter and the fabric thickness because of their influence on both ink deposit and print definition. Since screen printing inks can be formulated to adhere to almost any surface, and the printing process itself can be handled almost any substrate in a wide variety of shape, screen printing is a very versatile process. The small size pronting is reproduced image used screen printing because the surface of substrates is not suited at screen printing method. In screen printing, the need of high definition printing is gradually increasing according to developing special inks. A conventional haftone, so called AM screening, is simple and easy to implement, but the haftone dot patterns by using this method are not free for the moire fringe. This paper is used densitometry and image analysis to investigate relation with printing according to screen mesh, opening size and resolution of copy in image reproduction used FM screen. We had the good result of dot gain and tone reproduction on the screen printing of high definition using FM screen.

• 정신신체의학
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• 제3권2호
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• pp.147-158
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• 1995

This paper describes the development of Korean version of two widely used self-report measure of alexithymia-Schalling-Sifneos Personality Scale (SSPS) and Toronto Alexithymia Scale(TAS), and present the preliminary results of their reliability and validity tested to an Korean college student sample(N=206). TAS showed moderate to acceptable internal consistancy with 0.26 of mean item-total correlation and 0.754 of Cronbach's alpha coefficient, while those parameters for SSPS turned out inconsistent. However, results of test-retest reliability for both scale were excellent. Factor analysis revealed tow factors for TAS and three factors for SSPS ; the four-factor structure of TAS was quite congruent with previously known alexithymaia construct, while, again, SSPS showed intermixed factor structure. TAS scores correlated fairly well with somatization scores enough to get concurrent validity while SSPS scores did not. Overall, Korean version of TAS demonstrated well matched findings in terms of internal consistency and factorial validity with original and Spanish version of TAS. The results suggest that Korean version of TAS could be a useful and reliable tool for the measurement in Korean population.

• 한국토양비료학회지
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• 제14권4호
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• pp.179-184
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• 1982

담수(湛水)된 논 토양(土壤)에서 열전달(熱傳達)은 전도(傳導)에 의(依)한 과정(過程)과 물 이동(移動)에 의(依)한 과정(過程)이 복합(複合)되어 있다. 이 열전달(熱傳達) 과정(過程)을 방정식(方程式)으로 나타내고 그 분석해(分析解)를 구(求)하였다. 분석해(分析解)는 1) 온도(溫度)의 일교차(日較差)(또는 연교차(年較差))는 Sine 함수식(含數式)에 따르며 2) 무한(無限)한 깊이에서의 온도(溫度)는 변(變)하지 않고 3) 일정(一定) 깊이에서의 수온(水溫)과 지온(地溫)은 동일(同一)하다는 가정하(假定下)에서 이루어졌다. 토양(土壤)의 열보유능(熱保有能), 용적밀도(容積密度), 공극율(孔隙率)과 투수속도(透水速度) 및 두지점(地點)에서의 최고(最高) 최저온도(最低溫度)를 알면 본해(本解)를 이용(利用)하여 토양(土壤)의 열광산계수 D; Thermal Diffusity, $cm^2/hr$)를 계산(計算)할 수 있다. 본(本) 연구(硏究)에서 얻어진 열광산 계수(係數)는 투수계수(透水係數)가 0.88cm/day인 양토(壤土)에서 $9.5cm^2/hr$, 투수계수(透水係數)가 2.64cm/day인 사양토(砂壤土)에서 $13.9cm^2/hr$이었다.