• Korean Journal of Human Ecology
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• v.7 no.2
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• pp.113-119
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• 1998

The purpose of this study was to investigate the effect of geometrical structure on the heat transfer of insulating nonwovens. Commercially available single and double layered polyester nonwovens have used. Thermal conductivity, k and thermal conductance, h were measured by using a constant temperature sandwich type device at dry and wet state. The results obtained were as follows: 1. Double layered nonwovens showed slightly lower thermal conductance and higher warmability than single layered nonwovens. 2. As moisture regain increased, double layered nonwovens showed higher increasing rate of thermal conductivity than single layered nonwovens.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.2
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• pp.80-87
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• 2011

Low temperature hole transport characteristics of gate-all-around p-channel metal oxide semiconductor (PMOS) type silicon nanowire field-effect-transistors with the radius of 5 nm and lengths of 44-46 nm are presented. They show coexisting two single hole states randomly switching between each other. Analysis of Coulomb diamonds of these two switching states reveals a variety of electrostatic effects which is originated by the potential of a single hole captured in the trap near the nanowire.

• Solar Energy
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• v.19 no.1
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• pp.77-86
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• 1999

The optimal thermal design of a single heat source on one wall of a vertical open top cavity was studied experimentally. The temperature and flow fields in the cavity were visualized. The objectives of this study is to obtain the best location of the single heat source and to examine the effects of heat source protrusion, substrate thermal conductivity and cavity aspect ratio on the natural convection cooling due to a single heat source. As the results, the cooling effect for the copper substrate is superior to that of the epoxy-resin substrate and is improved with increasing cavity width. For the epoxy-resin substrate of lower conductivity, the protrusion of the heaters plays a role in decreasing the cooling effect. The best location was the mid-height of the substrate.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.736-737
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• 2007

The single point bonding in underground transmission system can induce high voltage on the sheath when ground fault, lightning serge and switching serge occurs, at that time underground cable systems cannot offer a return path of fault current. Accordingly if fault current, which cannot return to ground, flows at the single point bonding, high voltage can be induced in SVL and that voltage can cause aging and breakdown of SVL. Therefore this paper study on the effect of parallel ground conductor at the single point bonding when ground fault and lightning serge occurs by using ATPDraw.

• Journal of Korean Association for Spatial Structures
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• v.19 no.1
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• pp.53-64
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• 2019

The objective of this study is to investigate the earthquake response for the design of 100m spanned single-layer lattice dome. The plastic hinge analysis and eigenvalue buckling analysis are performed to estimate the ultimate load of single-layered lattice domes under vertical loads. In order to ensure the stability of lattice domes, it is investigated for the plastic hinge progressive status by the pushover increment analysis considering the elasto-plastic connection. One of the most effective methods to reduce the earthquake response of large span domes is to install the LRB isolation system of a dome. The authors discuss the reducing effect for the earthquake dynamic response of 100m spanned single-layered lattice domes. The LRB seismic isolation system can greatly reduce the dynamic response of lattice domes for the horizontal and vertical earthquake ground motion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.465-475
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• 2018

The purpose of this study was to explore predictors of positive changes in children with divorced parents and to demonstrate the structural path among the perceived experience of social discrimination, parenting difficulties, parent-child communication, and internet use of children that related to positive changes based on family incomes. The subjects for this study were 1,114 single parents from divorced families sourced from a study on the status of single-parent families in 2015. The results of this study by using the structural equation model of the moderating effect verification with family incomes and multi group analysis are as follows. First, single-parent's perceived experience of social discrimination turned had a significant positive effect on parenting difficulties( =.354) and children's internet use ( =.234). Single-parent's perceived parenting difficulties also had a significant positive effect on children's internet use ( =.440) but a significant negative effect on both parent-child communication( =.192) and positive changes of children( =.218). Interestingly, internet use of children demonstrated a significant negative effect on their positive changes. Second, parent-child communication, parenting difficulties, and children's internet use had a negative mediating effect with the relationship where single-parent's perceived experience of social discrimination had an effect on positive changes of children( =.167). Second, between the family groups based on family incomes, there was no statistically significant difference in the structural relationship. Based on these results, this study presented a practical proposal to help single parents not experience social discrimination and to help decrease the internet use of children to improve positive changes.

• Journal of Ocean Engineering and Technology
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• v.6 no.1
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• pp.96-104
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• 1992

Aircraft structures and engineering structures are always subject to variable amplitude loads. Variable amplitude loads include some kind of loading history; for example, constant amplitude load, single peak overload and block overload etc. Crack growth under variable amplitude loading exhibits retardation effect. In this study, the 4 point bending fatigue test was performed by hydrolic servo fatigue testing machine on 7075-T6 Al-alloy. The retardation effect of overload ratio and numbers of overload cycle was quantitatively studied. 1) Change of retardation effect against increment of overload ratio is more evident when the multiple overload is applied than single overload is done. 2) The number of overload cycle is very important factor about the crack growth retardation effect when the overload ratio is more than 1.75; that is not when the overload ratio is less than 1.75. 3) Overload affected zone size increased gradually by increment of crack growth retardation effect. 4) Crack driving force is more greatly reduced when the crack tip branched off two direction than it sloped to one direction.

• Journal of Environmental Science International
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• v.27 no.6
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• pp.359-369
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• 2018

A model has been developed to predict natural ventilation in a single zone building with large openings. This study first presents pressure-based equations on natural ventilation, that include the combined effect of wind and thermal buoyancy. Moreover, the concept of neutral pressure level(NPL) is introduced to consider the two-way flow through a large opening. The total pressure differences across the opening and the NPL are calculated, and nonlinear equations are solved to find the zonal pressure to satisfy mass conservation. For this analysis, an iterative technique of successively approximating the zonal pressure is used. The results of applying this study model to several simple cases are as follows. When there is no wind and only the stack effect is caused, a one-way flow occurs in both the top and bottom openings in the case of two openings of equal-area, and a one-way flow occurs in the top opening; however, a two-way flow occurs in the bottom opening in the case of two openings of unequal-area. When there is a wind effect, regardless of whether the outside air temperature is lower or higher than the indoor air temperature, air flows into the room through the bottom opening and out of the room through the top opening. As the wind velocity increases, the wind effect appears to be more influential than the stack effect owing to the temperature difference.

• Toxicological Research
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• v.11 no.2
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• pp.267-271
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• 1995

A single large dose of ethanol as well as chronic ethanol consumption produces alcoholic fatty liver in human and experimental animals. We examined the effects of YH439, a potential hepatoprotective agent, on alcoholic fatty liver generation in adult female rats. In rats treated with YH439 (250 mg/kg, po) 4 hr prior to a single dose of ethanol (6 g/kg, po), a significant decrease in hepatic triglyceride accumulation was observed. YH439 also has an inhibitory effect on hepatic triglyceride and cholesterol accumulation induced by repeated ethanol treatments for one week. Because it has been known that induction of alcoholic fatty liver is associated with lipid peroxidation and/or hepatic glutathione depression, the effect of YH439 on these parameters was determined in the livers of rats treated with ethanol. Coadministration with YH439 inhibited MDA formation and gIutathione depression induced by acute or repeated ethanol administration. In order to determine the effect of YH439 on ethanol metabolism in vivo, disappearance of ethanol from blood was measured. In rats treated with a single dose of ethanol (6 g/kg, po), the ethanol concentration in blood reached a peak approximately 120 min following the treatment which declined linearly for 18 hrs. YH439 had no effect on the decline of blood ethanol concentration regardless of the dose of ethanol given to rats. These results in this study suggest that YH439 has an inhibitory effect on fatty liver generation induced by acute or repeated ethanol consumption through a mechanism not directly related to the rate of ethanol metabolism in vivo.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.201-207
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• 2019

An anchorage system is essential for most reinforced concrete structures to connect building components. Therefore, the prediction of strength of the anchor is very important issue for safety of the structures themselves as well as structural components. The prediction models in existing design codes are, however, not applicable for large anchors because they are based on the small size anchors with diameters under 50 mm. In this paper, new prediction models for strength of a single anchor, especially the tensile strength of a single anchor, is developed from the experimental results with consideration of size effect. Size effect in the existing models such as ACI or CCD method is based on the linear fracture mechanics which is very conservative way to consider the size effect. Therefore, new models are developed based on the nonlinear fracture mechanics rather than the linear fracture mechanics for more reasonable prediction. New models are proposed by the regression analysis of the experimental results and it can predict the tensile strength of both small and large anchors.