• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.892-895
• /
• 2005

This study investigated changes of mechanical characteristics in the trabecular and cortical bone of the lumbar vertebrae of the ovariectomised(OVX) rat. In previous researches, there were many studies for morphology of osteoporotic bones based on Micro-CT (Micro - Computed Tomography). However, there were few studies for detecting and tracking changes of mechanical characteristics in the trabecular bone and cortical bone of the lumbar vertebrae for the OVX rat. For this study, one female Sprague-Dawley rat was used: an OVX rat. The 4th lumbar of the OVX rat was utilized as a specimen. Detecting and tracking changes of mechanical characteristics could be investigated in the trabecular and cortical bone of the lumbar vertebrae for an OVX rat using In-vivo Micro-CT. An OVX rat was scanned at week 0 (just before surgery), at week 4, and week 8 after surgery. Micro finite element(${\mu}\;FE$) analysis was used to investigate mechanical characteristics in the trabecular and cortical bone of the lumbar vertebrae for an OVX rat.

• Korean journal of food and cookery science
• /
• v.19 no.1
• /
• pp.46-59
• /
• 2003

Backsulgi were prepared with the addition of nutriprotein powder at 0%, 2%, 4%, 6%, 8%, and their sensory quality and mechanical characteristics were compared. In addition, the changes in the sensory and textural characteristics of Backsulgi were determined while storing them at the temperatures of 4$^{\circ}C$ and 20$^{\circ}C$ for 0, 1, 2, and 3 days. In the sensory evaluation, Backsulgi with 4% nutriprotein powder showed the highest score in overall quality. In the measurement of color changes, L value (lightness) was decreased, but a value (redness) and b value (yellowness) increased as the addition of nutriprotein powder increased. In textural characteristics, the hardness, gumminess and cohesiveness of Backsulgi were decreased by the increase of nutriprotein powder. The hardness and gumminess were increased as the storage time increased.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.27 no.2
• /
• pp.41-50
• /
• 1999

The purpose of this study is to find out the changes in geomorphic characteristics of a small watershed when a golf course is constructed. The research site is a set of seven small watersheds including an 18-hole golf course that were randomly selected. The size, shape, and drainage network of watersheds were measured by using planimeter, watershed eccentricity, and stream order, respectively. In addition, a 25m$\times$25m mesh was used on topographic maps and grading plans in order to obtain the slope, elevation, and aspect of the watersheds. The major results of this research, while investigating of the changes in geomorphic characteristics of watersheds when a golf course is constructed, are as follows: 1. The size of watersheds is increased in accordance to the difference in elevation between the golf course site and the small watershed. 2. The watershed eccentricities are in general similar except for a few low-valued cases. 3. The changes in the average altitude and the gradient are more drastic with their bigger original values. 4. The aspects are changed more with decreasing elevation. 5. The stream order decreases in the case of a low watershed eccentricity. 6. The surface modification has a closer relationship to the slope rather than the size of effective use area. 7. With a steeper gradient and an excessively low gradient, the height of cutting/filling is increased.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.46 no.3
• /
• pp.390-406
• /
• 2022

This study aims to establish the optimal environmental conditions for storing textile products. Four textile products (cotton, wool, nylon, cotton/polyurethane) were used to produce experimental fabrics according to artificial contamination and washing conditions. Each fabric was subjected to three environmental conditions (A: 20-25℃/20% RH, B: 20-25℃/50% RH, C: 30-35℃/65% RH) for 4-12 weeks. Changes in textile characteristics include tensile strength, wrinkle recovery rate, and odor intensity. Results show that the change in tensile strength for the four test fabrics slightly decreased with a storage time of 4 to 12 weeks. The wrinkle recovery rate of the fabrics was the lowest under the C condition. UV exposure causes a substantial decrease in the tensile strength of the textiles. The change in odor characteristics was the highest for the odor intensity in the C condition. For storing textile products for sustainable management, it is desirable to maintain a temperature of 20 to 25℃ with a relative humidity of 50% RH or less and to provide ventilation in an enclosed storage space that can also block UV rays.

• The Research Journal of the Costume Culture
• /
• v.12 no.5
• /
• pp.832-844
• /
• 2004

The purpose of this study is to explain innovative changes of men's fashion in 'a cyber society', which has come with the advent of internet revolution and where we have witnessed social changes in view of sex, race and class. As for the research methodology, literary research was under taken to study characteristics of cyber society. And demonstrative studies on men's fashion were undertaken through the analysis of photos. 'Cyber space' is defined as 'a communication network of informations and opinions' or 'pseudo world created by computer technology'. Our current world, which has continuous interaction with cyber space, can be understand as cyber society. In a cyber society, transcendental structure is not accepted, feminine characteristics appear more frequently, and western-biased territorial features lose its ground. These characteristics are rooted in ideological characteristics of cyber society, such as opposition and composition. Considering the characteristics of cyber society, the aesthetic images of men's fashion in cyber society can be explained with de-authoritarianism, 　metrosexualism and multi-culturalism.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.06a
• /
• pp.191-197
• /
• 2001

Performance requirements for automatic transmission fluids have been changing to reflect the design changes of automatic transmission. The major purpose for these design changes is to improve fuel economy and drivability. The use of special base oils like API Group III and IV base oils has increased in order to formulate high performance ATF. In this study. the effect of base oils characteristics on ATF performance is investigated, mainly regarding differences in frictional characteristics with deterioration. Moreover, low-temperature fluidity. oxidation stability. and seal compatibility are also compared for four different ATFs. From the investigation, it was found that the use of Group III and IV base oils in ATF has several benefits in low temperature viscosity. oxidation stability and SAE No.2 friction characteristics.

• Korean Journal of Applied Biomechanics
• /
• v.34 no.2
• /
• pp.63-70
• /
• 2024

Objective: This study aims to compare the basic aerodynamic characteristics of the official Qatar World Cup soccer ball with those of the official Korean soccer balls. Method: In this study, wind tunnel experiments were conducted to compare the fundamental aerodynamic properties of two commonly used domestic soccer balls, the Star and Nassau, with the Al Rihla, the official ball of the 2022 Qatar World Cup. Results: The findings revealed that the Nassau soccer ball exhibited changes in aerodynamic characteristics depending on its orientation, particularly at low speeds (below 15 m/s), while the Al Rihla showed variations in aerodynamic characteristics at medium to high speeds (15 m/s to 35 m/s) based on its orientation. Furthermore, the results of lift and side force variations indicated that the Star soccer ball exhibited larger changes compared to other soccer balls, suggesting that it may exhibit the most irregular flight path during strong shots (around 30 m/s or approximately 100 km/h). However, there were no differences in aerodynamics observed among the soccer balls in the medium-speed range (20~25 m/s). Conclusion: The comparison of aerodynamics between the Korean soccer balls and the most recently used World Cup official ball showed that, while the Korean balls exhibited slightly greater changes in lift and side forces compared to the World Cup ball, there were no significant differences in most of the aerodynamic characteristics.

• Tribology and Lubricants
• /
• v.31 no.5
• /
• pp.213-220
• /
• 2015

This study evaluates the effect of grooves on the stem part of a plunger on the lubrication characteristics of a fuel injection pump (FIP) by using hydrodynamic lubrication analysis. The current study uses the two-dimensional Reynolds equation to evaluate the changes in lubrication characteristics with variations in clearance, viscosity, and grooves for a laminar, incompressible, and unsteady state flow. This study investigates the lubrication characteristics by comparing the dimensionless minimum film thickness or the film parameter, which is the ratio of the minimum film thickness to surface roughness. The analysis method for the groove section differs depending on the depth of the groove. For instance, in the case of a shallow groove, the film thickness equation considers the depth of the groove, while in the case of a deep grove, it considers the flow continuity. The lubrication characteristics of the FIP are more sensitive to changes in the groove width than to changes in other design variables. Moreover, the application of a groove is more effective under low viscosity conditions. The smaller the distance from the edge of the stem part to the first groove in the case of shallow grooves, the better are the lubrication characteristics of the FIP. In contrast, in the case of deep grooves, the lubrication characteristics of the FIP improve as the distance increases. The application of shallow grooves is more effective for improving the lubrication characteristics than the application of deep grooves.

• KSTLE International Journal
• /
• v.2 no.2
• /
• pp.120-126
• /
• 2001

Performance requirements for automatic transmission fluids have been changed reflecting the design changes of automatic transmissions. The major purpose of these design changes is concentrated upon improvements of both fuel economy and drivability. In order to formulate such high performance ATFs as satisfy those requirements, it is necessary to use high quality base oils like VHVI base oils and PAOs. In this study, the effect of base oils characteristics on ATF performance is investigated, mainly regarding differences in frictional characteristics with deterioration. Frictional characteristics are determined using the SAE No. 2 machine and ATFs are deteriorated under various controlled conditions. Moreover low-temperature fluidity, oxidation stability, and seal compatibility are also compared for four different ATFs. From the investigation, it was found that the use of Group III and IV base oils in ATFs gives several benefits with respect to low temperature viscosity, oxidation stability and SAE No.2 friction characteristics.

• Journal of Families and Better Life
• /
• v.31 no.3
• /
• pp.27-47
• /
• 2013

The purpose of this study was to investigate whether parent education programs conducted in South Korea were effective in changing in parents' behaviors, parents' internal characteristics, and children's characteristics. We retrieved journal articles published in Korea between 2006 and 2011 using keyword searches of electronic databases. A total of 41 studies were included in our meta-analyses. The results showed that parent education programs had large positive effects on parents' behavioral changes and children's changes along with medium to large effects on parents' internal changes. The strengths of effect sizes varied depending upon program characteristics including children's age, the number of participants, participants' gender, the number of sessions, and group characteristics. This study provided powerful scientific evidence for public policies and services that aim to support and empower parents by providing parent education programs.