• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.497-500
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• 2004

Recently, the use of structure compound waterproof agent (hereinafter referred to as 'SCWA') that is used when manufacturing concrete for concrete structures, increases in quantity. However, while it is expected that the SCWA that is mixed in the concrete inside can significantly affect the change of physical properties that lift the internal force of a structure. This study has been conducted through an experiment for the effects of cement hardener on the formation of microscopic texture, and newly generated hydrates from that result were not confirmed in the present experiment. It was found that at the hydrate reaction it has the property that can be hardened within the limit of pore diameterar a specific size rather than there is the internal gap filling capacity due to generating other hydrates.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.777-780
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• 2004

Recently, the use of structure compound waterproof agent (hereinafter referred to as 'SCWA') that is used when manufacturing concrete for concrete structures, increases in quantity. However, while it is expected that the SCWA that is mixed in the concrete inside can significantly affect the change of physical properties that lift the internal force of a structure. This study has been conducted through an experiment for the effects of cement hardener on the formation of microscopic texture, and newly generated hydrates from that result were not confirmed in the. present experiment. It was found that at the hydrate reaction it has the property that can be hardened within the limit of pore diameterar a specific size rather than there is the internal gap filling capacity due to generating other hydrates.

• Journal of computational fluids engineering
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• v.18 no.2
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• pp.85-92
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• 2013

In this study, we consider heat transfer enhancement in laminar channel flow by means of an infinite streamwise array of equispaced identical circular cylinders. This flow configuration can be regarded as a model representing a micro channel or an internal heat exchanger with cylindrical vortex generators. A numerical parametric study has been carried out by varying Reynolds number based on the bulk mean velocity and the cylinder diameter, and the gap between the cylinders and the channel wall. An immersed boundary method was employed to facilitate to implement the cylinders on a Cartesian grid system. No-slip condition is employed at all solid boundaries including the cylinders, and the flow is assumed to be periodic in the streamwise direction. Also, the Prandtl number is fixed as 0.7. For thermal boundary conditions on the solid surfaces, it is assumed that heat flux is constant on the channel walls, while the cylinder surfaces remain adiabatic. The presence of the circular cylinders arranged periodically in the streamwise direction causes a significant topological change of the flow, leading to heat transfer enhancement on the channel walls. The Nusselt number averaged on the channel wall is presented for the wide ranges of Reynolds number and the gap. A significant heat transfer enhancement is noticed when the gap is larger than 0.8, while the opposite is the case for smaller gaps. More quantitative results as well as qualitative physical explanations are presented to justify the effectiveness of varying the gap to enhance heat transfer from the channel walls.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.11
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• pp.1640-1649
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• 2001

The present study investigates the effects of various rib arrangements on heat/mass transfer in the cooling passage of gas turbine blades. A complex flow structure occurs in the cooling passage with rib turbulators which promote heat transfer on the wall. It is important to increase not only the heat transfer rates but also the uniformity of heat transfer in the cooling passage. A numerical computation is performed using a commercial code to calculate the flow structures and experiments are conducted to measure heat/mass transfer coefficients using a naphthalene sublimation technique. A square channel (50 mm $\times$ 50 mm) with rectangular ribs (4 mm $\times$ 5 mm) is used fur the stationary duct test. The experiments focus on the effects of rib arrangements and gap positions in the discrete ribs on the heat/mass transfer on the duct wall. The rib angle of attack is 60°and the rib-to-rib pitch is 32 mm, that is 8 times of the rib height. With the inclined rib angle of attack (60°), the parallel rib arrangements make a pair of counter rotating secondary flows in the cross section, but the cross rib arrangements make a single large secondary flow including a small secondary vortex. These secondary flow patterns affect significantly the heat/mass transfer on the ribbed wall. The heat/mass transfer in the parallel arrangements is 1.5 ∼2 times higher than that in the cross arrangements. However, the shifted rib arrangements change little the heat/mass transfer from the inline rib arrangements. The gap position in the discrete rib affects significantly the heat/mass transfer because a strong flow acceleration occurs locally through the gap.

• KIEAE Journal
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• v.11 no.2
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• pp.75-82
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• 2011

In Korea, the ratio of population in urban areas used to be only 50.1% in 1970, but with the value risen to 90.8% in 2009, urbanization is going on rapidly. Urbanization, which occurs by the rampantly planted buildings, has become major source of raising building density, changing wind direction and reducing wind amount, and such reductions are affecting even inside the building. In each year, among the total energy consumption in Korea, residential portion takes up significant ratio, and specifically the ratio of apartment house is shown to be highest. In order to solve such problem, many studies are being conducted for the improvement of natural ventilation performance. The natural ventilation performance of apartment house are significantly determined by the characteristics of external and internal structure, but in macroscopic perspective, the performance is established fundamentally by the layout characteristics of the main building of the apartment house in preparation for wind conditions. So far researches on raising the thermal comfort through elevation of ventilation performance have been conducted actively, but many of them propose only theoretical concepts deduced through wind path analysis, and do not include any indicator to measure ventilation performance simply only with area data from layout planning stage. Therefore, in this study, gap ratio a wind field measuring indicator was developed, and after the ventilation characteristics by layout types and main building uniformity were identified, the scope of gap ratio efficient for ventilation and that of uniformity were clarified, followed by verification through simulation.

• Journal of the Korean Institute of Gas
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• v.20 no.1
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• pp.29-39
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• 2016

Electrical apparatuses for use in the presence of explosive gas atmospheres have to be special designed to prevent them from igniting the explosive gas. Flameproof design implies that electrical components producing electrical sparks are contained in enclosures and withstand the maximum pressure of internal gas or vapours. In addition, any gaps in the enclosure wall have to designed in such a way that they will not transmit a gas explosion inside the enclosure to an explosive gas or vapours atmosphere outside it. In this study, we explained some of the most important physical mechanism of Maximum Experimental Safe Gap(MESG) that the jet of combustion products ejected through the flame gap to the external surroundings do not have an energy and temperature large enough to initiate an ignition of external gas or vapours. We measured the MESG and maximum explosion pressure of propane and acetylene by the test method and procedure of IEC 60079-20-1:2010.When the minimum MESG is measured, the concentration of propane, acetylene in the air is higher than the stoichiometric point and their explosion pressure is the highest value.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.75-89
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• 2021

In this paper, the results of analyzing the meaning of laughter in comedy movies of the late 1960s, focusing on comedians, Hee-Gap Kim, Bong-Seo Koo and Young-Chun Seo, are as follows. First, the narrative laughter of the comedians represents the generational conflict between the lower class and the upper class, the gender conflict between men and women, and the frustration of reality. Second the mechanism of creating laughter of the comedians shows ridicule of the conservative older generation, revelation of the immoral upper class, and caricature of the frustrated lower class. Third, the practical aspect of the comedians' laughter reveals cracks in tradition and modern, gaps in economic inequality, and expression of prohibited desires. Therefore, comedians Hee-Gap Kim, Bong-Seo Koo and Young-Chun Seo in comedy movies of the late 1960s show the semantic effect of laughter of internal/external boundaries and optimistic world views through the closed opening of informal culture and the conflict of characters/performers.

• Journal of Distribution Science
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• v.13 no.6
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• pp.87-96
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• 2015

Purpose - Several domestic telecommunication companies have made a considerable effort to continuously grow and survive, and they have strived to thrive in the midst of mature market competition. To overcome this challenging situation and to grow continuously, while still meeting customer needs that are becoming more diverse and complicated with the passage of time, extensive support for internal marketing is essential. Without such internal support, companies face serious limitations and market roadblocks. The communication industry is a high-level service industry and a basic communications industry characteristic is its significant dependence on the employees delivering the services. Therefore, entrepreneurs in the information/communications industry, as well as existing competitors, should look to satisfy external customers through critical investment in internal customers (employees). Therefore, it is important for research to examine how internal factors influence technology innovation and service quality, which are the key drivers for companies that are seeking leading market positions. Research design, data, and methodology - The purpose of this study is to analyze the relationship of technology innovation and perceived service quality with the internal marketing factors in the communication industry and to offer suitable and effective internal marketing suggestions. The independent variables of this study are internal communication, education and training, the support of the executives, reward systems, and empowerment. The dependent variables are technology innovation and perceived service quality. Utilizing these, this paper studies the influence of internal marketing factors on technology innovation and perceived service quality. Results - The study results revealed the following. First, the identified internal marketing factors have a positive effect on technology innovation. Among the five internal marketing factors, three had a significant effect on product innovation, empowerment, the support of executives, and education and training, in this order. Second, the internal marketing factors also had a positive effect on the process innovation of technology innovation. The marketing factors, the support of executives, empowerment, internal communication, and education and training, in this order, significantly affect process innovation. Third, technology innovation had a positive effect on perceived service quality. All of the five service quality factors, namely, tangibles, reliability, assurance, responsibility, and empathy, in this order, significantly affect product innovation. Additionally, tangibles, reliability, responsibility, empathy, and assurance, in this order, significantly affect process innovation. Fourth, product and process innovation significantly affect tangibles and reliability in technology innovation. To enhance tangibles and reliability, process innovation should first be enhanced. Fifth, product and process innovation significantly affect responsibility and empathy in technology innovation. To enhance the responsibility and empathy, process innovation should first be enhanced. Sixth, product and process innovation significantly affect assurance in technology innovation. To enhance the assurance, product innovation should first be enhanced. Conclusions - According to the results, a company's internal marketing factors have a positive and significant effect on technology innovation and, further, product and process innovation have a positive and significant effect on the perceived serviced quality.

• Restorative Dentistry and Endodontics
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• v.37 no.1
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• pp.41-49
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• 2012

Objectives: The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

• The Journal of Korean Medicine
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• v.34 no.3
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• pp.126-142
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• 2013

Objectives: Previous reports have shown that Bogijetong-Tang (BJT) is effective in peripheral neuropathy induced by taxol and crush injury. In this study, we researched the effects of BJT on diabetic neuropathy induced by STZ in the mouse. Methods: We performed both in vitro and in vivo experiments to verify the effects of BJT on diabetic neuropathy induced by STZ in mice. Changes in axonal recovery were observed with immunofluorescence staining using NF-200, Hoechst33258, $S100{\beta}$, caspase 3 and anti-cdc2. Proliferation and degeneration of Schwann cells were investigated by immunofluorescence staining and western blot analyses. Results: BJT showed considerable effects on neurite outgrowth and axonal regeneration in diabetic neuropathy. BJT contributed to the creation of NF-200, GAP-43, Cdc2, phospho-vimentin, ${\beta}1$, active ${\beta}1$, ${\beta}3$ integrin, phospho-Erk1/2 protein. Conclusions: Through this study, we found that BJT is effective for enhanced axonal regeneration via dynamic regulation of regeneration-associated proteins. Therefore, BJT had a pharmaceutical property enhancing recovery of peripheral nerves induced by diabetic neuropathy and could be a candidate for drug development after more research.