• 대한조선학회논문집
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• 제53권2호
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• pp.162-169
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• 2016

A new concept of membrane type LNG CCS was proposed. Also, its static behavior was numerically analyzed considering the interaction between primary and secondary barrier together with securing device. Hull deflection was taken into account as an external load, together with temperature distribution across the barriers. The suggested numerical model considers both sliding and contact between the two mating surfaces of both the primary and secondary barrier, and anisotropic material behavior of plywood, R-PUF was also taken into account. Furthermore, detailed local strength was evaluated for the securing device, which is arranged between two barriers to hold the primary barrier. It was confirmed through the numerical analysis that the new concept of membrane type CCS was structurally safe under static loading condition and securing concept was structurally reliable.

• 한국환경생태학회지
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• 제28권3호
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• pp.273-280
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• 2014

본 연구는 번식기 북방산개구리(Rana dybowskii)를 대상으로 고속도로 소음지역과 자연지역에서 울음소리 차이가 있는지 분석하였다. 연구대상지는 강원도 원주시 영동고속도로변 논 2개소와 소음 영향이 없는 자연지역 논 2개소를 선정하였다. 울음 녹음은 2014년 2월 24일, 2월 27일, 3월 14일, 18:30~20:00 사이에 진행하였다. 북방산개구리 번식기 울음은 자연지역에서 700Hz대에서 기음이 형성되었으며, 2~4개의 배음이 관측되었다. 반면 고속도로 소음지역 번식기 울음은 보다 높은 주파수대에서 기음이 형성되었을 뿐 아니라 배음도 2~7개까지 관측되었다. 분산분석 결과, 고속도로 소음에 직접 노출된 논에 서식하는 개구리 울음소리 제1배음의 주파수가 다른 지점에 서식하는 개구리 울음소리 주파수 보다 통계적으로 유의미하게 높은 것으로 나타났다. 하지만 고속도로와 인접한 지역이라 하더라도 지형의 단차가 있고 산림으로 막혀 있어 고속도로 소음에 의한 직접적인 영향을 받고 있지 않은 지점의 경우는 자연지역과 개구리 울음소리 차이가 없는 것으로 나타났다. 이는 북방산개구리가 고속도로 소음 환경에서 자연지역보다 고주파 영역에서 더 많은 배음을 만들어서 에너지 효율적으로 자동차 소음에 의한 음향 간섭을 피하기 때문으로 판단된다. 이 결과는 또한 인공적인 소음에 의한 개구리 번식을 방해하지 않기 위해서는 이 임계수준 이하로 서식처 소음 환경을 관리하는 것이 필요하다는 것을 시사해 준다.

• 한국정밀공학회지
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• 제23권10호
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• pp.74-79
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• 2006

In this study, the tempering effect on the wear characteristics of induction-hardened SPS5 steel was investigated. For this purpose, three tempering conditions were applied to control the hardness of heat-treated SPS5 steel. Ball-on-disk wear tests have been performed using zircornia balls on the tempered specimens to determine the variation of wear characteristics. The results showed that friction coefficient decreased with increasing hardness for induction hardening conditions. This seems to occur because real contact area between specimen and mating ball was affected by the specimen hardness.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2001년도 춘계심포지움 및 학술발표회
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• pp.131-131
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• 2001

내분비계장애물질에 대한 검색기법의 하나로 수컷 어류의 교배행위 및 생식력에 대한 in vivo 연구를 시도하였다. 수컷 송사리(Oryzias latipes)에 대표적 에스트로젠인 17$\beta$-estradiol를 2 및 20 $\mu\textrm{g}$/L의 농도로 각 노출군당 5마리씩 14일간 노출시킨 후 각 군당 임의로 2마리씩 선택하여 Prostaglandin F2$\alpha$를 주사한 3마리의 정상 암컷 송사리와의 교배행위를 비디오 카메라를 이용하여 1시간 동안 녹화하여 분석하였다. (중략)

• Tribology and Lubricants
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• 제8권1호
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• pp.63-69
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• 1992

In order to gain better understanding of wear behaviors of TiN-coated boron cast iron, tests and analyses were conducted with block-on disc type tribometer. TiN layer of thickness $2 \mu m$ and $4 \mu m$, coated by cathodic arc evaporation process, were experimentally investigated with the variation of applied load and sliding speed under dry sliding condition. Wear characteristics were expressed in terms of the three-dimentional wear map as well as the wear rate vs sliding speed and load. Comparisons of wear and friction characteristics between coated cast irons and uncoated cast irns were also made. Wear mechanism of TiN layer was explained in view of surface interaction between the mating surfaces. The thicker coating exhibited higher hardness and adhesion strength. the significance of stresses at the surface and in the subsurface was briefly discussed in relation to the wear behavior.

• 생태와환경
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• 제40권4호
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• pp.581-585
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• 2007

Swarm formation of Scapholeberis kingi Sars 1903 was observed in a shallow reservoir on 27 May 2007 (Dongpan Reservoir) for the first time. Dense swarms composed of asexual females, only occurred during daytime (13:00-17:00, local time) at the littoral zone. Correlation between density of S. kingi and environmental factors such as water temperature and density of juvenile fish were positively significant. Therefore, it is suggested that the swarming of S. kingi seems to be induced for predator avoidance than increase of mating chance, and water temperature may affect their swarming behavior.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.409-410
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• 2006

In this study, the tempering effect on the wear characteristics of induction-hardened SPS5 steel was investigated. For this purpose, three tempering conditions were applied to control the hardness of heat-treated SPS5 steel. Ball-on-disk wear tests have been performed using zircornia balls on the tempered specimens to determine the variation of wear characteristics. The results showed that friction coefficient decreased with increasing hardness for induction hardening conditions. This seems to occur because real contact area between specimen and mating ball was affected by the specimen hardness.

• 대한기계학회논문집
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• 제13권2호
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• pp.229-235
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• 1989

본 연구에서는 편면도금 강판과 복합조직 고장력 강판간의 이종 용접재의 피로거동을 연구하고져 한다. 즉 유한요소법으로 응력분포를 조사하고 그 결과와 피로균열발생 위치를 비교 검토해 보고자 한다.

• 한국발생생물학회지:발생과생식
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• 제18권1호
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• pp.25-31
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• 2014

This study was investigated spawning behavior, structure of egg masses and egg development in Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea. The mating and courtship behavior of A. kurodai occurred in the form of unilateral copulating with chain formation. In chain copulation, only the first animal acted as a female; the second and succeeding animals acted as males (sperm donors) to the animals in front and as females to the animals behind. The fertilized eggs were packaged in capsules that are embedded in jelly to form a cylindrical string called an egg masses. The number of capsule per cm of the egg masses was 55 to 60 capsules and each capsule within the egg masses held 15 to 25 eggs. After spawning, the egg masses were bright yellow or orange in color. This egg masses color not changed until embryos developed into trochophore stage. Thereafter, as embryo developed from trochophore stage to veliger stage the egg masses color became brownish. The fertilized eggs were spherical, with a diameter of approximately $80{\pm}1{\mu}m$ at spawning. At 5 to 6 days after spawning, the embryo developed into trochophore stage and began to rotate within the egg capsule. In the trochophore stage, the precursor of the velum, called the prototroch or prevelum, developed. At 10 days after spawning, the prevelum is transformed into the velum, and the trochophore developed into veliger stage. Between 10 to 15 days after spawning, the veligers broke out of the egg capsule, and hatched as free-swimming larvae.

• Tribology and Lubricants
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• 제37권1호
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• pp.25-30
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• 2021

The surface texture produced via surface texturing is an important approach for controlling the tribological behavior of friction behavior of mechanical devices. The purpose of this study is to investigate the effect of grooves generated via ultrasonic nanocrystal surface modification (UNSM) technology on the tribological performance of AISI 4150 steel against stainless steel 316L. In the study, tribological tests are performed under two different regimes, namely mixed and hydrodynamic lubrication, by varying the applied normal load and reciprocating speed during the tests. According to the test results, the friction coefficient decreases as static load (10 N, 30 N, and 50 N) of UNSM technology increases in the mixed lubrication regime. Conversely, the friction coefficient increases as the static load (10 N, 30 N, and 50 N) of UNSM technology increases in the hydrodynamic lubrication regime. Hence, the results indicate that micro-grooves generate hydrodynamic pressure in the outlet, which increases the oil film thickness between the two mating surfaces. This potentially leads to a reduction in friction in the mixed lubrication regime due to the prevention of contact of asperities and debris. However, the results indicate an adverse effect in the hydrodynamic lubrication regime. In this regard, additional experiments should be performed to investigate the effect of grooves generated by UNSM technology at varying conditions on the friction behavior of AISI 4150 steel, which in turn can be controlled by the generated pressure and oil film thickness at the contact interface.