• Design & Manufacturing
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• v.8 no.1
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• pp.27-30
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• 2014

Alloy tool steel such as SKD11 and SKD61 or high speed tool like SKH51 are used as materials for semiconductor dies. Cavities, curl blocks, pot blocks and housings are made from those materials. To make those parts from alloy tool steel or high speed tool, one utilizes discharge machining, and mechanical machining including machining center, milling, drilling, forming grinding and others. In the process of cutting machining and polishing, the die materials become unsuitable for machining owing to bubbles and foreign substances in them, which hinders production process. Therefore, this study focuses on die material selection criteria, and on analysis and comparison of material characteristics to help companies to solve their problems, make die manufacture less burdensome and extend die life.

• 전기의세계
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• v.28 no.1
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• pp.73-82
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• 1979

There are a great number of papers on the Townsend discharge in gases, and many of them are concerned with the effect of the cathode. It has been regarded that there are two kinds of effect of the electrodes, especially of the cathode; (a) the effect caused by the difference of the cathode material and (b) the effect by the change of the cathode surface state even in the same material. Both of them may change the secondary coefficient following after the change of the work function, and the atter may further change the primary ionization coefficient as foreign atoms on the surface may be dseorbed in sparks to decrease the purity of the gas. Thus the two effects must be investigated independently to study the roles of the cathode in gas discharges. In this report the effect of the cathode material on the sparking voltage is described. The experiment is also carried out under the condition that the desorption of impurities from the cathode be negligible. From these the new correlativity between the work function of the cathode and the sparking voltage is obtained. In addition, the interesting character of the minimum point of the Paschen's curve can be found.

• Journal of the Korean housing association
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• v.15 no.4
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• pp.75-86
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• 2004

This research is about the Korean private residence as the actual housing published in Kuchie, 'Chosun and Architecture'. Research about the Korean private residence during the Japanese colonial period is important to find out the influence of foreign culture on Korean housing during that period. This research is necessary to reveal the tendency of modernization of Korean housing and how the foreign cultural relationship transformed and applied to the Korean housing. This research was carried out mainly on the 16 Korean private residences published in 'Chosun and Architecture'. The main subject of this research is to analyze the architectural floor plan, building material and heating facilities etc. Other important themes of the research are the practical side of actual housing plan, interior furnitures and fittings, electrical fittings and the classification of life style.

• Journal of Trauma and Injury
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• v.30 no.2
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• pp.51-54
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• 2017

We here report a case of long-term fistula formation due to bullet retention for 30 years in the lumbar spine after a gunshot injury, and describe its treatment. A 62-year-old male visited our hospital due to pus-like discharge from his left flank. The discharge had been present for 30 years, since his recovery from an abdominal gunshot injury. A spine radiography showed radiopaque material in the body of the third lumbar vertebra. Foreign body was removed using an anterolateral retroperitoneal approach. The postoperative course was uneventful. The patient was discharged 7 days after the operation and was followed-up for 8 months, during which time, the fistula did not reoccur. A bullet retained long term in the vertebral body may cause obstinate osteomyelitis and fistula formation. A fistula caused by a foreign body in the spine can be effectively treated by surgical removal.

• Journal of the Korean Arthroscopy Society
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• v.3 no.1
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• pp.51-53
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• 1999

A four-year-old boy with knee pain who had an obscure history showed radiopaque material in the radiograph of the medial side of the knee joint. We successfully treated removal of a piece of glass by arthroscope followed by debridement of erosive cartilage and torn meniscus.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.9-14
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• 2008

This study was carried out environment-friendly factors in domestic and foreign domed stadium, and was derived environment-friendly factors of built domed stadium and these are divided into 3 parts; energy, indoor environment and material & resource. In addition, this study analyzed characteristics of application about environment-friendly fector related its space size and climate.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.121-134
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• 2002

Tunneling is a very dangerous and expansive work. Especially, the concrete lining works need many long hours and much cost. As an alternative, the unlined tunneling methods including NMT have been developed in various country. These methods have advantages in cost, time and quality. In Korea, many considerations have been conducted to apply the unlined tunneling method in comparatively good rock. Since primary reinforcements play the role of the final supporting system in unlined tunnels, the initial stiffness and long term durability of reinforcements are very important for tunnel safety. To establish the reinforcements standard suitable to Korea, we investigated the foreign standards and construction cases, comparing geological and construction conditions of foreign land and Korea. As the result, we have proposed the standard of primary supporting system for unlined tunnel in aspects of material, design, construction and quality control etc.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.247-258
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• 2008

Environmental standards for beneficial uses of dredged materials are proposed. Even though chemical analysis of ocean sediments are carried out frequently, their analyses results were not interrelated with the effects of biological lives due to a shortage of biological data. These facts have resulted in difficulty to develope Korean's standards of recycling dredged materials. This paper first searched existing current foreign standards, analyzed local contaminated ocean sediment data, identified their main chemical components of contaminants, and then compared with clean-up standards of sediments consisting of lower and higher levels. From these analysis, new environmental standards considering Korean domestic circumstances are proposed. It is judged that new standards are appropriate to both Korean national sedimental environments and economically recycling aspects because environmental standard levels proposed are higher than background levels of sediments in Korean and foreign standards.

• Journal of Korean Association for Spatial Structures
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• v.8 no.3
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• pp.37-44
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• 2008

The purpose of this study is to derive a basic data for environment-friendly factors and design methods which is applicable to domestic domed stadium. Thus this study carry out environment-friendly factors in domestic and foreign domed stadiums through the case studies. And these are divided into 3 parts; energy, indoor environment and material & resource. Also this study analyzed environment-friendly factor application characteristics which is related its space size and climate.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.844-846
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• 1999

Chronic irritation to arterial wall by foreign material may give rise to delayed vascular injury. A 50 years old male patient with kyphoscoliosis had undergone fixation of orthopedic Cotrel-Dubousset(CD) rods and screws. Fourteen months after that surgery, a false aneurysm of the descending thoracic aorta associated with pulsating hematoma in the muscular chest wall developed. The false aneurysm was managed by resecting the diseased aortic segment and replacing the vascular graft.