• Journal of Family Resource Management and Policy Review
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• v.5 no.1
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• pp.49-60
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• 2001

This research examined elderly’s quality of life(q/l). In order to explore the elderly’s q/l, it was conceptualized into 8 dimensions tapping macro and micro aspects of elderly’s life: physical & mental health, self-esteem, anxiety, social support, family solidarity, economic state, and physical environment. The primary purposes were to describe dimensions of q/l by the elderly’s sociodemographic variables. And the intercorrelations among q/l dimensions were examined and then the effects of q/l sub-dimensions on psychological well-being were analyzed by using multiple regression. Based on the data collected for 677 subjects residing in rural and urban areas, the basic issues hypothesized were explored. The findings appeared that the psychological well-being was a positive function of physical and mental health, self-esteem, social support, and economic state and a negative one of social anxiety, controlling for subjects’s sociodemographic variables.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.58-68
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• 1999

This study was carried out to verify the distribution patterns of Salix gracilistyla and Phragmites japonica communities known as obligatory riparian species according to physical factors such as micro-landforms, substrates, etc., at Soo-ip stream corridor. Firstly four vegetation types - Salix gracilistyla dominant type, Phragmites japonica dominant type, mixed type of two species, and mixed type of two species to other species, were classified by cluster analysis based on UPGMA-Euclidean distance. Also these vegetation types showed many different distribution patterns in response to the longitudinal and lateral view along the stream corridor and substrate composition. Salix gracilistyla was major component of dominant vegetation types developed at attack point of bending reach and on substrates composed of rock fragments, but contrastly Phragmites japonica was most important component of dominant vegetation types at point bar of bending reach and floodplain, and on substrates composed of soil materials. Secondly the species and environment biplot form CCA strongly supported the vegetation types divided by classification. Namely Salix gracilistyla was closely correlated with rock fragments and steep slope, which is resistant to physical action even though located near running water. But Phragmites japonica showed a high correlation with soil particles sedimented at floodplain by divergent flow.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.163-174
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• 1985

The requirements of orthodontic wire should include chemical stability, non-discoloration and non-corrosion in oral environment. Ability to be soldered, ease of fabrication and elasticity should be also considered. The purpose of this study was to compare and analyze the physical properties of Tru-chrome wire and manufactured E.S.S. (Experimental Stainless Steel) wire similar to Tru-chrome. The results were as follows: 1. Tru-chrome wire and E.S.S. wire were SUS 304 which was 18 Cr-8Ni austenite stainless steel. There was not significant difference in each composition between two wires. 2. There were not significant differences in ultimate tensile strength, yield strength, elongation and modulus of elasticity between Tru-chrome and E.S.S. wires. 3. There was not significant difference between flexuree modulus of elasticity of Tru-chrome and E.S.S. wires. 4. Micro-hardness value of E.S.S. wire was more than that of Tru-chrome wire and they were softened significantly by solution heat reatment. 5. Micro-structure of Tru-chrome and E.S.S. wires showed fibrous interlocking grains, and an austenite structure after solution heat treatment. 6. There was significant difference between corrosion rate of Tru-chrome and E.S.S. wires.

• Journal of Soil and Groundwater Environment
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• v.19 no.1
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• pp.34-45
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• 2014

A variety of physical, chemical, and microbiological techniques have been developed to deal with soil and groundwater contamination. However, in the presence of the large portion of soil micro-environments, contaminant rebound and/or tailing have been frequently reported. Case study of total petroleum hydrocarbons (TPH) removal by full-scale land farming showed that contaminant rebound and/or tailing occurred in 9 out of total 21 cases and subsequently resulted in problems of a long term operation to satisfy TPH guidelines of contaminated soil and groundwater. The main cause of contaminant rebound and tailing is considered to be the strong interactions between contaminants and micro-environments including micro-particles, micro-pores, and organic matter. Thus, this study reviewed the effects of soil micro-environments of soil and groundwater on the removal efficiency for both heavy metals and petroleum contaminants. In addition, the various methods of sampling, analysis, and assessment of soil micro-environments were evaluated. Thorough understanding of the effects of soil micro-environments on contaminant removal will be essential to achieve a cost-effective and efficient solution to contaminated sites.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.29-46
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• 1999

The performance based design obligates quantitative assessment of required performances by means of transparent and objective science. In this design scheme, simulation of both macro and micro-scale structural behaviors is thought to be a powerful tool. This paper proposes a way how to unify the structural safety and serviceability check method and durability assessment of RC structures. Though component chemical-physical processes are crudely assumed, system dynamics of micro-scale pore structure formation and macro-scale defects and deformation of structures was shown as possible and promising approach in future. The authors understand that the unification of structural and durability design has just started. For further progress and development, predictive tool of structural behaviors from birth to death of concrete under any specified environment and load serves as an essential technicality.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.207-210
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• 2005

Ubiquitous computing is one of the key technology areas in the "Project on Development of Ubiquitous computing and network technology" promoted by the Ministry of Science and Technology as a frontier business of the $21^{st}$ century in Korea, which is based on the new concept merging physical space and computer-based cyber space. With recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low-power consumption wireless micro sensor nodes have been available. Using these smart sensor nodes, there are many activities to monitor real world, for example, habitat monitoring, earthquake monitoring and so on. In this paper, we introduce web-based real environment monitoring system incorporating wireless sensor nodes. It collects sensing data produced by some wireless sensor nodes and stores them into a database system to analyze. Our environment monitoring system is composed of a networked camera and environmental sensor nodes, which are called Mica2 and developed by University of California at Berkeley. We have modified and ported network protocols over TinyOS and developed a monitoring application program using the MTS310 and MTS420 sensors that are able to observe temperature, relative humidity, light and accelerator. The sensed data can be accessed user-friendly because our environment monitoring system supports web-based user interface. Moreover, in this system, we can setup threshold values so the system supports a function to inform some anomalous events to administrators. Especially, the system shows two useful pre-processed data as a kind of practical uses: a discomfort index and a septicity index. To make both index values, the system restores related data from the database system and calculates them according to each equation relatively. We can do enormous works using wireless sensor technologies, but just environment monitoring. In this paper, we show just one of the plentiful applications using sensor technologies.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.892-901
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• 2018

Because of excellent electrical properties, epoxy resin is widely used in packaging and casting power equipment. Moisture and temperature in the environment are inclined to seriously affect the insulation tolerance of epoxy resin. This work focuses on the aging characteristics of epoxy resin in hygrothermal environment. Scanning electron microscopy images show that there are micro-crack, micro-slit and holes inside aged samples. The moisture absorption process undergoes three equilibrium stages and it does not follow the Fick's second law. Observing the change of hydrogen bonds in the infrared spectra of the dried samples, it is found that chemically moisture absorption immerges when the physical moisture absorption entered the third equilibrium stage. By Debye equation to fit the imaginary part of the dielectric constant, it is concluded that the uniformity of water molecule has a great influence on the electrical conductivity loss. Furthermore, the polarization loss can be more easily affected by water molecules than small free molecules. After the aged samples being dried, their real and imaginary part of the dielectric constant descend, but their original electrical properties cannot completely restored. After chemical moisture absorption appears inside the material, the residual space charges increase significantly and the charge dissipation rate slow down obviously.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.516-521
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• 2019

The top seeded solution growth (TSSG) method is an alternative technique to grow high-quality SiC crystals that has been actively studied for the last two decades. However, the TSSG method has different issues that need to be resolved when compared to the commercial SiC crystal growing method, i.e., physical vapor transport (PVT). A particular issue of the TSSG method of results from the presence of liquid droplets on the grown crystal that can remain even after crystal growth; this induces residual stress on the crystal surface. Hence, the residual droplet causes several unwanted effects on the crystal such as the initiation of micro-cracks, micro-pipes, and polytype inclusions. Therefore, this study investigated the formation of the residual droplet through multiphysics simulations and lead to the development of a liquid droplet removal method. As a result, we found that although residual liquid droplets significantly apply residual stress on the grown crystal, these could be vaporized by adopting thermal annealing processes after the relevant crystal growing steps.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.4
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• pp.93-101
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• 2010

The purpose of this study is to provide basic data for utilization in environment-friendly and economically outstanding CSG construction method by physical and mechanical properties of CSG materials including characteristics of uniaxial compressive strength, microscopic structure and freezing and thawing resistance in accordance with the cement content and curing time of the cement, and size of specimen. In this study, specimens with cement content of 4, 6, 8 and 10% of the total weight were, and, in order to examine the characteristics of the sizes of specimen, specimens with ${\Phi}50{\times}100mm$, ${\Phi}100{\times}200mm$ and ${\Phi}150{\times}300mm$ were manufactured to assess the features including compressive strength, microscopic structure, freezing and thawing, and degree of wet-dry. As results, it was found that with greater size specimen or contents of cement in the specimen, compressive strength, freezing and thawing resistance, and wet-dry resistance increase. Moreover, reactive products for each size of specimen were examined and it was possible to verify that some typical needle structured ettringite was generated due to blending of cement through microscopic structure analysis such as SEM and EDS analysis.

• KIEAE Journal
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• v.14 no.4
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• pp.133-138
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• 2014

The present study was carried out to assess the basic material properties and thermal behavior of light-weight foamed concrete panel mixed with PCM (Phase Changing Material). To do so, this study fabricated light-weight foamed concrete (1.0kg/m3) in pre-foaming method and mixed it with PCM micro capsule of 1-dodecanol and melamine to examine its physical and thermal properties. The results confirmed strength reinforcement effect by proper replacement ratio of fly-ash, which is an industrial by-product, and PCM. In addition, it found out that PCM-mixed light-weight foamed concrete had time delay and temperature reduction effect within the range of PCM phase transition according to the rise of outdoor temperature. It was also observed that the insulation performance of PCM-mixed light-weight foamed concrete was more dependent upon thickness than PCM replacement ratio.