• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.6
• /
• pp.745-750
• /
• 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.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.6
• /
• pp.69-74
• /
• 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
• /
• v.37 no.4
• /
• pp.327-332
• /
• 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.

• Korean Journal of Family Social Work
• /
• no.55
• /
• pp.31-58
• /
• 2017

This study aims to explore the longitudinal reciprocal relationship between family conflict and depression level of household head. Using the Korean Welfare Panel study (KOWEPS) of 2006-2009, the study applied multiple regression analysis and autoregressive cross-lagged model to test the hypothesis. Results of multiple regression analysis indicate that single direction of the impact of family conflict on a head of household's levels of depression and the vise versa were statistically significant. That is, higher level of family conflict in 2006 caused an increased levels of depression of household head in 2009, controlling gender, age and depression level in 2006. Also, the higher level of depression of household head in 2006 increased the level of family conflict in 2009 fixed with same control variables. The autoregressive and cross-lagged coefficients of family conflict and a head of household's levels of depression were statistically significant during the 4 years. The findings support the family system theory, indicating that there are reciprocal causal relationships between the whole family conflict and individual depression level. The strategies of social welfare practice and policy should thus aim to decrease individual's levels of depression and improve positive family function simultaneously to break the vicious circle.