• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.281-284
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• 2008

Inundation of substation and ground power equipment breaks out every summer season in low-lying downtown and low-lying shore by localized heavy rain, typhoon and tidal wave. In case inundation excluding the exchanging cost of equipment, it occurs a great economic and social loss owing to recovery time and events of electric shock occur by inundation electrical equipment(Pad-mounted Transformer and Switch). In case of installing the power equipment at flood danger territory, we are necessary to the product development, the product is that water does not come in the inside the power equipment. Product of pressure maintaining are established on the basic frame and sensor operates at the flooding occurrence and is maintained a shutting tightly structure and it is a method. The product which is produced the reliability of the product it confirmed a flooding yes or no from the condition which puts in the water tank and it verified. We estimate that loss cost which is caused by with flooding and the power failure will be diminished if it is addition to advances the reliability evaluation and a security of the flood protection product.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.857-864
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• 2016

Many plane, UAV and drone fly in the sky as development of aviation industry. Plane and UAV fly and drone's propellers rotate so fast. Impact between flying objects which have high velocity threats passengers. Also the impact damages people, building and various property. Plane's operating speed is near sound velocity(340m/s), and propeller's rotating speed is less than that. Until now, impact experiment uses gas gun to get speed and the gun needs large space to entirely air expansion. Electromagnetic launcher, especially railgun, needs smaller space than gas gun to get enough speed about 500m/s. This paper explains electromagnetic launcher's operating principle, shows making electromagnetic launcher design guide line and suggests that it is a better apparatus to get low-high velocity.

• Design & Manufacturing
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• v.12 no.2
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• pp.16-21
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• 2018

Recently, as the demand for high-precision parts increases due to industrial development, a machine tool system for ultra-precision machining and polishing has been actively developed. As a result, there is an increasing demand for ultra-precision surface roughness along with dimensional processing. However, due to the increase in processing time due to the demand for ultra-precise surfaces and enormous facility investment, it is difficult to secure competitiveness. The polishing process using the abrasive film in super precision machining has been applied to machines, electronic devices, aerospace, and medical fields. Super finishing using the abrasive film which is applied in the industrial field recently can achieve high surface roughness in a short time. Super finishing using the abrasive film which is applied in the industrial field recently can achieve high surface roughness in a short time. Also, application of industrial field is increasing due to advantages such as low noise and low dust. Recently, researches on stainless steel having strong resistance to corrosion, heat resistance, heat resistance, toughness and weldability have been actively conducted with respect to the nuclear energy industry or marine development. Therefore, in this study, surface roughness and residual stress were measured after SUS304 polishing using dynamic analysis of film polishing apparatus and polishing film.

• The Plant Pathology Journal
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• v.29 no.1
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• pp.17-30
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• 2013

Barley stripe mosaic virus (BSMV) induces massive actin filament thickening at the infection front of infected Nicotiana benthamiana leaves. To determine the mechanisms leading to actin remodeling, fluorescent protein fusions of the BSMV triple gene block (TGB) proteins were coexpressed in cells with the actin marker DsRed: Talin. TGB ectopic expression experiments revealed that TGB3 is a major elicitor of filament thickening, that TGB2 resulted in formation of intermediate DsRed:Talin filaments, and that TGB1 alone had no obvious effects on actin filament structure. Latrunculin B (LatB) treat-ments retarded BSMV cell-to-cell movement, disrupted actin filament organization, and dramatically decreased the proportion of paired TGB3 foci appearing at the cell wall (CW). BSMV infection of transgenic plants tagged with GFP-KDEL exhibited membrane proliferation and vesicle formation that were especially evident around the nucleus. Similar membrane proliferation occurred in plants expressing TGB2 and/or TGB3, and DsRed: Talin fluorescence in these plants colocalized with the ER vesicles. TGB3 also associated with the Golgi apparatus and overlapped with cortical vesicles appearing at the cell periphery. Brefeldin A treatments disrupted Golgi and also altered vesicles at the CW, but failed to interfere with TGB CW localization. Our results indicate that actin cytoskeleton interactions are important in BSMV cell-to-cell movement and for CW localization of TGB3.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.77-86
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• 1998

A combined technology of transvaginal ovum pick-up(OPU) system with in vitro-oocyte manipulation technique can be used for improving reproductive efficiency in the cattle. The objective of this study was to establish a newly-conceived breeding program using OPU in the pregnant cows. The OPU trial was performed in pregnant cows every 10 days from 40 through 90 days of artificial insemination (Al), and number of follicles in ovary, number of retrieved oocytes and embryo development following in vitro-fertilization, were evaluated. Reduced number of follicles in the ovaries of pregnant cows was firstly detected from 70 days after A' and a significant (P<0.05) decrease in the follicle number (5.4 follicles /donor) was found at 90 days than at 40, 50, 60 and 80 days after Al (8.0~9.2). A similar pattern was also observed in the number of oocytes retrieved by OPU apparatus during experimental period. When retrieved oocytes were matured and inseminated in vitro with frozen bull semen, development of the oocytes to the blastocyst stage was not significantly affected by the retrieval time. Four embryos (morula or blastocyst stage) derived from oocytes retrieved from pregnant cows were nonsurgically transferred to four recipient cows on day 7 of estrus cycle. For the first time in Korea, three of four transferred embryos developed to live calves with normal physiological parameters. In conclusion, an effective breeding program employing pregnant cow can be developed by use of OPU trial and in vitro culture techniques of oocytes ; OPU system could be repeated in pregnant cows with no risk of abortion and viable offsprings were borne after transfer to the recipients.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.257-265
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• 2000

Harderian glands are the unique organs in several mammals, which human and non-human primates do not have. We report the ultrastructural changes in the postnatal developmental periods of Harderian glands in Mongolian gerbil(Meriones unguiculatus). Male and female Mongolian gerbils were sacrificed on days 3, 10, 30 and 60 after birth and their Harderian glands were observed by transmission electron microscope. The obtained results were summarized as follows; 1. In 3-day-old Mongolian gerbils, Harderian gland was composed of one excretory duct and immature tubules which have two type cells, dark and light cells, identified electron-dense and electron-lucent respectively. 2. In 10-day-old Mongolian gerbils, small lipid vacuoles began to be found in the cytoplasm of the secretory cells of the Harderian gland. Mitochondria, Golgi apparatus, polysomes and slash were more abundant in the cytoplasm of dark cells than those of light cells. The arrangement of tubules in the gland was much more condensed than that of 3-day-old Mongolian gerbils. 3. In 30-day-old Mongolian gerbils, the secretory cells of the tubule were typically columnar in shape and there was one type cell in the tubule. Most of the columnar secretory cells contained various size vacuoles. 4. In 60-day-old Mongolian gerbils, the Harderian gland possessed the typical structural characteristics of adults. The mature glandular structures were more significant than those of 30-day-old animals.

• Journal of Korean Society on Water Environment
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• v.30 no.2
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• pp.166-174
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• 2014

Velocity gradient, G, a measure of the average velocity gradient in the fluid has been applied for complete mixing of chemicals in mechanical mixing devices. G values were calculated by the power input transferred to fluid in turbulent and transient range. Chemical reactions occur so fast that total mass transfer time required for even distribution of the chemicals determine the overall reaction time. The total mass transfer time is composed of the time for complete mixing through the reactor and for diffusion of the chemicals into the eddy. Complete mixing time was calculated by CFD (computer fluid dynamics) and evaluated by tracer tests in 2 liter jars at different rotating speeds. Turbulent range, Reynolds number above 10,000 in regular 2 liter jars occurred at revolution speed above 100 rpm (revolution per minute), while laminar range occurred at revolution speed below 10 rpm. A typical range of rotating speed used in jar tests for water and wastewater treatment was between 10 and 300 rpm, which covered both transient and turbulent range. G values supplied from a commercial jar test apparatus showed big difference from those calculated with power number specially in turbulent range. Diffusion time through eddy decreased 1.5 power-law of rotating speed. Complete mixing time determined by pumping number decreased increases in rotating speed. Total mass transfer time, finally, decreases as rotating speed increases, and it becomes 1 sec at rotating speed of 1,000 rpm. Complete mixing times evaluated from tracer tests showed higher than those calculated by power number at higher rotating speed. Complete mixing times, however, calculated by CFD showed similar to those of experimentally evaluated ones.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.550-551
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• 2013

Large-area RF-driven ion source is being developed at Germany for the heating and current drive of ITER plasmas. Negative hydrogen (deuterium) ion sources are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER and DEMO. RF ion sources for the production of positive hydrogen ions have been successfully developed at IPP (Max-Planck- Institute for Plasma Physics, Garching) for ASDEX-U and W7-AS neutral beam injection (NBI) systems. In recent, the first NBI system (NBI-1) has been developed successfully for the KSTAR. The first and second long-pulse ion sources (LPIS-1 and LPIS-2) of NBI-1 system consist of a magnetic bucket plasma generator with multi-pole cusp fields, filament heating structure, and a set of tetrode accelerators with circular apertures. There is a development plan of large-area RF ion source at KAERI to extract the positive ions, which can be used for the second NBI (NBI-2) system of KSTAR, and to extract the negative ions for future fusion devices such as ITER and K-DEMO. The large-area RF ion source consists of a driver region, including a helical antenna (6-turn copper tube with an outer diameter of 6 mm) and a discharge chamber (ceramic and/or quartz tubes with an inner diameter of 200 mm, a height of 150 mm, and a thickness of 8 mm), and an expansion region (magnetic bucket of prototype LPIS in the KAERI). RF power can be transferred up to 10 kW with a fixed frequency of 2 MHz through a matching circuit (auto- and manual-matching apparatus). Argon gas is commonly injected to the initial ignition of RF plasma discharge, and then hydrogen gas instead of argon gas is finally injected for the RF plasma sustainment. The uniformities of plasma density and electron temperature at the lowest area of expansion region (a distance of 300 mm from the driver region) are measured by using two electrostatic probes in the directions of short- and long-dimension of expansion region.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.119-126
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• 2015

The wall system has been also tending to shift from existing concrete wall to variable lightweight wall according to increasing use of column structure system in apartment construction. Therefore, wall needs certain amount of strength which also means the standard measurement of resistance against loading of wall attachments is needed. Nevertheless, there currently aren't enough researches of related standards for such measurement. For such reason, the research would be used as baseline data to development for test methods of load resistance about attachments on the lightweight wall, that presented improvements in the apparatus and maximum loads for domestic circumstances by researching current tests.

• Journal of Internet of Things and Convergence
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• v.8 no.6
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• pp.15-20
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• 2022

This study is about the development of a device that reduces bacterial diffusion and odor by improving the water quality of the toilet using ozone water. In public toilets used by an unspecified number of people, various pollutants and pathogens are present in the toilet. These substances that are harmful to the human are dispersed in the form of aerosols into the air through toilet flushing. Aerosols containing various contaminants may flow into the user's respiratory tract or spread to the skin and cover, serving as a medium for various diseases. In order to prevent this spread, it is essential to continuously maintain cleanliness inside the toilet. Therefore, in this study, ozone water that can improve the water quality of the toilet was used as a way to keep the toilet environment clean. A device that is mounted in a toilet tank and continuously generates ozone water to improve pollutants inside the toilet was designed and developed.