• Journal of the Korean Arthroscopy Society
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• v.3 no.2
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• pp.127-131
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• 1999

Avulsion fractures of the intercondylar eminence of the tibia are not uncommon. In the displaced avulsion fracture, anatomical reduction and firm fixation of fracture fragments are needed but the most of the conventional operative techniques including arthroscopic technique are relatively complex and need. The results were not always satisfactory due to the risk of postoperative complications such as wound infection, premature epiphyseal closure and loss of fixation after early motion etc. So we describe a simple and safe modified method of arthroscopic reduction and fixation for avulsion fractures of the intercondylar eminence of the tibia. In our thirteen cases, we achieved anatomical reduction and secure fixation using cannulated screw through the three arthroscopic portals (anterolateral, medial mid-patellar and central). Postoperatively, immediate limited range of motion of the knee and partial weight bearing were possible. Additional use of the washer afforded safe fixation of comminuted avulsion fracture. The advantage of this technique includes its technical simplicity, easy removal of hardware, ability to treat comminuted type IV fracture with washer, no additional skin incision, no damage to growing plate in growth children and less morbidity.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.97-104
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• 2015

This study is a part of the high pressure injection system development on the Turbo GDI engine in order to reduce smoke emission in case of using the low volatile(high DI) fuel which is used as normal gasoline fuel in the US market. Firstly, theoretical approach was done regarding gasoline fuel property, performance, definition of particle matters and its creation as well as problems of the high DI fuel. In this experimental study, 2L Turbo GDI engine was selected and optimized system parameter was inspected by changing fuel, fuel injection mode (single/multiple), fuel pressure, distance between injector tip and combustion chamber, start of injection, intake valve timing in engine dyno at all engine speed range with full load. In case of normal gasoline fuel, opacity was contained within 2% in all conditions. On the other hands, in case of low volatile fuel (high DI fuel), it was confirmed that the opacity was rapidly increased above 5,000 rpm at 14.5 ~ 20 MPa of fuel pressure and there were almost no differences on the opacity(smoke) between 17 MPa and 20 MPa fuel pressure. According to the SOI retard, smoke decrease tendency was observed but intake valve close timing change has almost no impact on the smoke level in this area. Consequently, smoke decrease was observed and 16% at 6000rpm respectively with injector washer ring installed. By removing injector washer to make injector tip closer to the combustion chamber, smoke decrease was observed by 46% at 5,500 rpm, 42% at 6,000 rpm. It is assumed that the fuel injection interaction with cylinder head, piston head, intake and exhaust valve is reduced so that impingement is reduced in local area.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.2 s.161
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• pp.197-205
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• 2007

We investigated the effects of washing on the mechanical properties and hand values of spandex/cotton and cotton single jersey fabrics. These knitted fabrics were subjected to 30 laundering cycles with a drum-type washer and were followed by drying at $65^{\circ}C$ with a tumble dryer. The mechanical properties of the cotton knitted fabrics changed greatly during the first washing and then suffered no further change in their properties as the number of washing cycle increased. However, the properties of the spandex/cotton knitted fabrics changed continuously throughout all the washing cycles. The cotton/spandex knitted fabrics showed higher values in tensile and bending properties than did the cotton knitted fabrics, though both kinds of fabrics showed less difference in shearing, surface and compression properties. The spandex/cotton knitted fabrics which had proper density had a higher THV for winter underwear after 30 repeated washings than did the cotton knitted fabrics, and the THVs of both fabrics decreased with the increase in the number of washing cycles.

• Design & Manufacturing
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• v.6 no.2
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• pp.84-89
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• 2012

In recent years, technology of press plastic working having made remarkable progress. We can say this because it facilitates mass production and have superior performances in machining speed and equivalency of quality than other processing methods. In characteristics of press plastic working, mold manufacturing according to characteristics of each product should be preceded before processing and it has a great influence on machining speed and quality of products and etc according to manufacturing method. Therefore, mold design technology is a critical technology in press plastic working. There are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment.

• Design & Manufacturing
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• v.6 no.2
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• pp.90-95
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• 2012

The sheet metal forming proceccing is very important and indispensable in the automotive industry because the accuracy of prsee worked parts is directly related to the automotive quality. But when making mold it is difficult and expensive to modify mold. mold design technology is a critical technology in press plastic working. When design the mold there are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment and perform a comparative evaluation of difference of abrasion loss mold with the alloy tool steel (STD11) and Tungsten Carbide (WC).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.75-81
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• 2006

Recently, customers interest about noise of household electric appliance is growing. so, designer of product must study to reduce noise of product. Specially, in case of household electric appliance such as washing machine, there was consumers' complaint about noise that is radiated under dehydrating condition. But, in the case of washing machine, identification of noise source is not easy when washing machine is under dehydrating condition. Because various noise source influence each other, it is difficult to find out pure contribution degree about output noise. Multi-Dimensional Spectral Analysis(MDSA) is method that can remove correlation between inputs each other and express pure contribution degree about output of single input. So in this study, we analyzed contribution of each noise source on transfer pass of noise that is radiated at dehydration of washing machine using MDSA.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1056-1063
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• 2007

Recently, there has been a growing consumer interest in the amount of noise produced by household electrical appliances. The designer of the product must identify the source of the noise, in order to reduce the noise. In the case of a household electric appliance such as the washing machine, there is consumer's complaint about the noise that is generated during the dehydrating condition. Because of several noise sources combined each other. It is difficult to identify the noise sources that contribute to the noise output. Multi-Dimensional Spectral Analysis (MDSA) is a method that can remove the correlation between different noise sources, and it expresses the key contributing factor as a unique output. This study utilized MDSA to analyze the contribution of each input in the noise output during the dehydrating condition.

• Korean Journal of Materials Research
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• v.17 no.11
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• pp.580-586
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• 2007

To enhance the reliability of a newly designed reciprocating compressor applied in a domestic compressor, accelerated life tests were developed using new definitions of the sample size and the $B_1$ life index. In $1^{st}$ accelerated life testing, the compressor was locked due to the fracture of the suction reed valve. The failure modes and mechanisms of the suction reed valve in the accelerated tests were found to be similar to that of the failed product in the field. The root cause of the failure was the overlap between the suction reed valve and the valve plate in the suction port. The missing parameters in the design phase were modified by expanding the trespan size, introducing tumbling process, changing the material and thickness for the valve, introducing a ball peening and brushing process for the valve plate. In $2^{nd}$ accelerated life testing, the compressor was locked due to the interference between the crank shaft and thrust washer. The corrective plan was to heat treat the crank shaft. The $B_1$ life of the compressor improved from 1.5 to 12.9 years.

• Progress in Superconductivity
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• v.1 no.1
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• pp.20-25
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• 1999

We constructed a high-$T_c$ scanning SQUID microscope (SSM) operating in the liquid nitrogen. We used a washer-type YBCO SQUID with inner and outer dimensions of $12{\mu}m$ and $36{\mu}m$, respectively, which was grown on the $SrTiO^3$ bicrystal substrate. The sample, rather than SQUID, was scanned using two stepping motors. We also developed readout electronics, stepping motor controller, and the software for system control and data display. We took images of various samples using our SSM and found that the spatial resolution is about $40{\mu}m$ and noise level is lower than $10^{-7}T/{\surd}Hz$ at 100 Hz and higher at lower frequencies. The noise level was much higher than that of a typical SQUID due to the other coupling from the electric parts. We present a simple argument on the inductive coupling between the sample and the SQUID which should be under-stood for the proper interpretation of the obtained images. By comparing the measured data with the simulation results the gap between the SQUID and the sample is estimated to be $40{\mu}m$.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.7
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• pp.1196-1204
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• 1997

Cotton, rayon/cotton, and Tencel twill weave fabrics were used to investigate the effect of fiber types on the cellulase washing finish. And twill. basket, and derivative weave cotton fabrics were used to study the weave effect. Various fabrics were treated with neutral cellulase varying treatment times and with acid cellulase, stone, and stone-neutral cellulase respectively for two hours in a rotary washer. Weight loss decreased in the order of rayon/cotton> cotton> Tencel, and basket and derivative weave fabrics lost more weight than twill weave fabric. Color difference decreased in the order of cotton> Tencel> rayon/cotton, and twill weave fabric had larger color difference than derivative and basket weave fabrics. Back staining decreased in the order of cotton> rayon/cotton> Tencel, and twill weave fabric had larger back staining than derivative and basket weave fabrics. Tear strength retention decreased in the order of rayon/cotton> cotton> Tencet and twill weave fabric had larger tear strength retention than derivative and basket weave fabrics. Flex stiffness retention decreased in the order of cotton> Tencel> rayon/cotton, and in the order of derivative> twill> basket weave. In cotton fibers, damage of primary wall was observed. And the cellulase treatment on Tencel seemed to roughen the fabric surface slightly, and to fibril fibers along the fiber axis.