• 한국생산제조학회지
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• 제20권6호
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• pp.745-750
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• 2011

A jig vise is a device to clamp workpiece precisely, which is widely used for various machine tools and manufacturing purpose. A new elastic structured jaw-wedge of jig vise is developed, in this paper, so as to satisfy the clamping requirement and the suppression effect of upright movement of workpiece. The advanced design parameters of jaw-wedge are derived step by step considering the stress distribution and the displacement profiles of ANSYS analysis, and it could find the optimum model which shows the uniform displacement profiles and exhibits the non-concentrated stress distribution of jaw neck. As a result, it is ascertained that an jaw-wedge developed in this study is the simple elastic structure which is effective for automatic multiple clamping purpose without the danger of shear crack or bucking of jaw.

• 한국기계가공학회지
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• 제16권6호
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• pp.69-74
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• 2017

In the current machining industry, machining precision is necessary and machining is being carried out. In this ultra-precision machining industry, the fixation of the workpiece is very important and the degree of machining depends on the degree of fixation of the workpiece. In ultra-precision machining, various methods, such as using a vise chuck or the like and using bolt nut coupling, are used for fixing a workpiece to an existing machine tool. In particular, when the precision gripping force of the jig is insufficient during machining of the ultra-precision mold parts, the machining material shakes due to the vibration or friction, and the machining precision is lowered. In the ultra-precision machining of power transmission parts, such as gears, the accuracy of the product is then determined. In addition, the amount of heat generated during machining has a significant effect on the machining accuracy. This is because the vibration value changes according to the grasp force of the jig that fixes the workpiece, and the change in the calorific value due to the change in the main shaft rotation speed of the ultra-precision machining. The increase in the spindle rotation speed during machining decreased the heat generation during machining, and the machining accuracy was also good, and it was confirmed that the machining heat changed according to the fixed state of the workpiece and the machining accuracy also changed. In this study, we try to optimize the driving part of the power vise by using structural analysis, rather than the power vise, using the basic mechanical-type power unit.

• Ocean and Polar Research
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• 제37권4호
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• pp.327-332
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• 2015

Isotopic compositions of ice and meltwater play a very crucial role in paleoclimate studies based on ice cores and water resources research conducted in alpine hydrogeology. Better understanding of variations in the stable isotopic compositions of water is required since changes from ice to liquid water are gaining more attention due to recent climate change. In this work, a melting experiment was designed and conducted to investigate how the isotopic compositions of ice vary with time by heat sources, such as solar radiation. We conducted the melting experiment for 22 hours. The discharge rate rose to a maximum value after 258 minutes and gradually declined because we fixed the heat source. The isotopic compositions of meltwater increased linearly or to a second degree polynomial. The linear relationship between oxygen and hydrogen has a slope of 6.8, which is less than that of the Global Meteoric Water Line (8) and higher than a theoretical value (6.3). The deuterium excess decreased when ${\delta}D$ or ${\delta}^{18}O$ increases or vise versa since the slope of the relationship for ice-liquid exchange is less than 8. These findings and the apparatus of the melting experiments will make a helpful contribution to the studies of stable isotopes and the melting process in temperate and polar regions.

• 한국가족복지학
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• 제55호
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• pp.31-58
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• 2017

본 연구는 가족갈등과 가구주 우울수준의 종단적 상호관계를 탐색하는 연구이다. 한국복지패널자료(2006-2009년)를 활용하여 가족갈등과 가구주 우울수준을 측정하였고, 다중회귀분석(multiple regression analysis)과 자기회귀교차지연모형분석(autoregressive cross-lagged model)을 통해상호영향력을 검증하였다. 본 연구의 주요 결과는 다음과 같다. 첫째, 가족갈등수준이 가구주의 우울수준에, 가구주의 우울수준이 가족갈등수준에 미치는 단일방향의 회귀계수는 관련 변수들을 통제한 상태에서도 각각 유의한 것으로 나타났다. 둘째, 가족갈등수준과 가구주 우울수준은 4년 동안 자기회귀계수와 교차지연회귀계수가 모두 유의한 것으로 나타났다. 이는 가족체계이론에서 제시하는 가족문제의 상호 순환론적 인과관계가 가족갈등과 가구주 우울수준의 관계에도 적용이 가능함을 시사한다. 이러한 결과를 바탕으로 가족갈등과 가구주 우울수준의 부정적 상호 순환 관계를 차단하기 위해 개인과 가족에 대한 동시적 접근의 필요성이 강조되었다. 본 연구의 이론적, 실천적, 정책적 함의가 논의되었다.