• Title/Summary/Keyword: foreign material

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Psophometeric Noise Voltage of Telecommunication Lines and Test methods (통신회선의 잡음전압 기준 및 측정법)

  • 황종선;김영민;이경욱;김재준
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.617-620
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    • 2001
  • The protection of communication lines against harmful effects from electricity lines is very important with the rapid development of communications network. This paper is introduced the reference of noise voltage and the test methods of foreign coutnreis. Further we will also present study measurement equipment for telecommunications noise voltage and circuit noise phenomenon.

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Tribological Characteristics for High Perfomance Metallic Friction Materials (고성능 금속마찰재의 트라이볼로지적 특성)

  • 김석삼;김재호;안효준
    • Tribology and Lubricants
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    • v.14 no.1
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    • pp.45-53
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    • 1998
  • Friction and wear test for two kinds of Cu-based sintered metallic friction material against cast iron disk was carried out by plate-on-disk type friction and wear tester to investigate the friction and wear characteristics of brake system in severe condition. In this experimental study, the counter specimen was cast iron which is being used generally in brakes of heavy duty equipments. Test friction materials were A type which was manufactured by foreign company and B type by domestic company. Friction coefficient and wear volume were measured and compared with each other. The experiment was performed under room temperature. The worn surface of cast iron disk and friction material were observed by scanning electron microscope. The temperature of surface of disk was measured continuously by the non-contacting thermometer. It was found that A type friction material had stable friction coefficient over the wide range of sliding condition, but B type friction material had unstable friction coefficient and lower value of 0.2 under the severe sliding condition.

Machinability Evaluation of Endmill Tool through Development of Ultra-fine Grain Grade Cemented Tungsten Carbide Material (초미립 초경소재 개발을 통한 엔드밀 공구의 성능 평가)

  • 김홍규;서정태;권동현;김정석;강명창
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.865-869
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    • 1997
  • In recent years, there has been increasing demand of ultra-fine grain graded cemented tungsten carbide material with high hardness and toughness which is used as high speed cutting tool for development in semiconductor, electronics and die/mold industry, which bring into limelight high-precision, high-efficient machining of sculptured surfaces. This paper deals with the performance of variation in the ultra-fine grain graded cemented tungsten carbide material such as grain size, hardness and density varied according to the volume of added elements, Co or TaC, and he changing of mixing, sintering process. Also, the performance of developing material with uniformed grain size of 0.5${\mu}{\textrm}{m}$ is compared with other domestics' & foreign companies' with analyzing and cutting performance testing.

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Prevention and management of foreign body ingestion and aspiration during the dental treatment (치과 치료에서 발생하는 이물질의 삼킴과 흡인의 예방과 대처)

  • Jeon, Han-Sol;Lee, Jin-Han
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.2
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    • pp.63-71
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    • 2018
  • Prosthetic restorations through implants were popularized, and they became routine treatments. Small accessories used in the implant prosthodontic procedure are more likely to slip or fall off the dentist's hands. If the dental appliance or material passes into the upper gastrointestinal tract, there is a high possibility of excretion to the outside of the body without complications, but serious complications may occur depending on the type of foreign body. If the foreign body is passed to the airway, it is an emergency situation, and if it is not done properly, it can be fatal. The purpose of this review report is to investigate the process of foreign body ingestion or aspiration during dental treatment, and the method of prevention and treatment.

A Surgical Treatment of the Esophageal Foreign Body (10 cases report) (수술적 처치가 필요했던 식도이물에 관한 임상적 고찰)

  • 황의두;황경환
    • Journal of Chest Surgery
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    • v.30 no.11
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    • pp.1117-1120
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    • 1997
  • Ten cases with esophageal foreign body were treated surgically from July 1980 to October 1995 at the Departme t of Thoracic and Cardiovascular Surgery, Chungnam National University Hospital. The mean age was 45.3 years, with a range from 25 to 71. Out of ten cases, 6 were female and four were male. Common symptoms were dysphagia, fever, foreign body sensation and neck pain. Three cases of foreign bodies were of fish bones, two of bubble paclcage of drugs, one case of a Eeer bottle cap, one of a piece glass, one of a bathtub plug, one of chicken and one of a bean. The diagnosis was established by esophagography using a water soluble contrast material and esophagoscopy. Among of ten cases, two had esophageal stricture due to the ingestion of Aye at a young age. One case had experienced psychological problems. All foreign bodies were removed by surgical procedures. Five cases were treated by cervical esophagostomy, one case by right thoracotomy, one case by retrograde bougienation through gastrostomy and two cases by cervical incision and drainage for cervical abscess. Three cases developed pos operative esophageal leaks which healed spontaneously and transient hoarseness developed in one case. One case developed traumatic pneumothorax and subcutaneous emphysema which was treated by closed thoracostomy. There were no operative deaths. C(ocean J Thorac Cardiovasc Surg 1997;30:1117-20)

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Surgical Removal of the Lung Lobe Metal Foreign Body in a Dog

  • Hwang, Yawon;Kang, Jihoun;Chang, Dongwoo;Kim, Gonhyung
    • Journal of Veterinary Clinics
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    • v.34 no.2
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    • pp.108-111
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    • 2017
  • A 4-year-old, weighing 7.6 kg, castrated male, Pug presented with ingestion of gastric cavity foreign body. Physical examination revealed panting, retching and hyper-salivation. Blood chemistry and complete blood cell count were normal, but hypophosphatemia was observed. An abdominal radiograph revealed the foreign body (FB), round shape and 2 cm length, at the pyloric region of stomach. A thoracic radiograph revealed an incidental metal FB, 3.5 cm length, at the cranial portion of the diaphragm. An upper gastrointestinal endoscopy was performed to remove the FB in the stomach and then a peach-pit was removed. However the metal FB was not found in the esophagus therefore a lateral thoracotomy was performed. A right lateral thoracotomy through the $7^{th}$ intercostal space was accomplished to expose the right caudal lung lobe. After open the thoracic cavity, foreign body was not observed by gross evaluation and caudal lung lobe was attached to the diaphragm. The FB was identified inside the lung lobe and surrounded by granulation tissue. The metal FB (sewing needle) was removed with blunt dissection and incised lung lobe was sutured using absorbable suture material PDS 4-0 with interrupted suture. A thoracotomy tube was inserted into the thoracic cavity during surgery. Patient's respiration became stable after surgery. A chest tube was removed 3 days after surgery. No complications were noted and the dog was discharged 4 days after surgery. In small animal, foreign body ingestion is a common reason for emergency. After ingestion of the FB, perforation through the esophagus and migration to inside the lung lobe is not common in small animals. In this case, thoracic metal FB was identified incidentally and removal of a thoracic FB with thoracotomy was performed successfully.

An Analysis of the Service Quality and Satisfaction Perceived by Users and Librarians on the Foreign Research Information Center (이용자와 상호대차담당자가 인식하는 외국학술지지원센터(FRIC)의 서비스품질과 고객만족도 분석)

  • Oh, Dong-Geun;Hwang, Jae-Young;Yeo, Ji-Suk
    • Journal of Information Management
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    • v.43 no.2
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    • pp.23-42
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    • 2012
  • This study is to investigate and analyze the service quality and satisfaction perceived by users and librarians of the Foreign Research Information Center (FRIC). The survey results reveal that three groups of in-campus (internal) user group, external user group and interlibrary loan librarian group has highly perceived the service quality and satisfaction of the FRIC. Two user groups have statistically significant different perceptions on the service quality, loyalty, and satisfaction. Internal user group perceived more highly than external user group, in 6 items of satisfaction, 1 item of loyalty, and 7 items of service quality. Structural equation models of satisfaction and loyalty on two user groups were proved to be appropriate. Material factor including success rate of copied text and general physical status of the copy influences significantly on the user satisfaction in both groups.

The Value of Film as Material for Learning a Foreign Language: Using Posh Discourse (영상자료가 지니는 외국어 학습 자료로서의 가치 : 공손한 언어를 중심으로)

  • Kim, Hye-Jeong
    • The Journal of the Korea Contents Association
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    • v.16 no.2
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    • pp.643-651
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    • 2016
  • This study considers the value of English-language films as material for learning a foreign tongue using posh discourse. In daily life, when we decline an invitation or convey unpleasant information to a listener, we use polite expressions; we are careful with our words. English language learners need to learn polite expressions in order to interact peacefully with others; doing so can minimize conflict, which is inherent in social relationships. This study uses the British drama Downton Abbey, which is about aristocracy. This study analyzes the posh discourse used in Downton Abbey and insists that students need to learn it explicitly. It is important to learn the polite expressions of this authentic drama in a real classroom. This study suggests that students work in groups to create a short video, and to try to understand the characters' personalities. Movies, TV dramas, and sitcoms provide great content that shows the various functions of the language that students want to learn. As a source of learning material, film can help improve students' motivation and interest in learning a foreign language.

A Study on Incombustibility of Building Service System Insulation Material (설비용 단열재 난연성 평가 현황과 개선 방안)

  • Park, Jong-Il;Kim, Suk-Hyun;Hong, Jin-Kwan;Lee, Min-Woo
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.999-1005
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    • 2006
  • The aim of this paper is to evaluation survey and improvement method of building service system insulation material incombustibility. In Korea, various insulation materials are being used to prevent energy losses. Performance of insulation materials is gradually advanced, and new insulation materials are developed and being used. We don't have prefer test standard of insulation material incombustibility. In this paper we investigate domestic and foreign standard about incombustibility Through the authors will show how we can improve incombustibility test standard in Korea.

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A study on the mass production performance evaluation of servomotors for manufacturing robots (제조 로봇용 서보모터의 양산성능 평가 연구)

  • Ryu, K.H.;Lee, T.H.;Park, J.W.;Kwon, H.S.;Kang, B.S.
    • Journal of Drive and Control
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    • v.19 no.4
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    • pp.91-96
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    • 2022
  • The performance and reliability of foreign servomotors and domestic servomotors for manufacturing robots were compared and verified. The mass productivity was confirmed by satisfying the requirements of the demanding companies. The servomotor was designed in consideration of mass productivity while satisfying the requirements of the demanding company. It was mounted on a real robot to check its performance and reliability. To secure mass-production performance, we designed and manufactured easy-to-manufacture parts and jigs to manufacture servomotors and achieved the goal of the mass-production evaluation of servomotors through individual performance evaluation, robot mounting test evaluation, and supplementation.