• Title/Summary/Keyword: 차폐막

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Stainless Steel Fiber 충전 PC/ABS 복합재료의 전자파 차폐용 재료로서의 특성

  • 박정민;정성훈;송석규
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.481-484
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    • 1998
  • 전자산업의 급속한 발전과 정보사회로 변화해 감에 따라 각종 전자장비의 사용이 증가하게 되었다. 그러나 전자장비에서 발생하는 전자파에 의한 기기 상호간의 장해현상과 인체에 대한 유해성 등이 새로운 문제로 대두되게 되었다. 이러한 전자파를 효과적으로 차폐하기 위한 하우징 재료를 만들기 위한 여러 가지 노력이 진행되고 있는데 가장 널리 쓰이는 방법은 기존의 재료에 코팅 또는 페인팅 등을 이용하여 전도성 막을 형성시키는 것이나 이는 부가공정에 의한 추가비용, 내구성 등의 문제가 있다. (중략)

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A study on Manufacture of EMI Composite Powder by the Electroless Ni Plating Method (무전해 니켈도금방법을 이용한 EMI 복합분말제조에 관한 연구)

  • Joung, I.;Yoon, S.R.;Han, S.N.;Na, J.H.;Kim, C.W.
    • Korean Journal of Materials Research
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    • v.8 no.5
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    • pp.444-449
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    • 1998
  • There are various shielding materials that have been considered; the use of a metallic plate or the layering of a conductive material on a plastic surface and the insertion of filler in plastics. All of these methods have shown their merits and weakness. Therefore, many studies have concentrated on developing materials that effectively cut down EMI without increase in weights of housing materials. In these respects, this study has focused on investigations of the shielding effect of materials that have electroless nickel plating on the lamella structured micro particles surface with low specific gravity. When a film of electroless nickel were plated on a micro particle surfaces and then mixed with paint, the electromagnetic shielding effects were measured as 63dB. Although these effects were less than that 90dB of the copper plate, trials in a series of 6 times increased the shielding effect by IOdB and is applicable to wide range of EMI shielding.

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Optimal Height of Shielding Plate of Radiation in Posteroanterior Chest Radiography for Pregnant Women on Korea (한국인 임산부의 흉부 후-전 방향 방사선검사 시 적절한 차폐막 높이)

  • Joo, Young-Cheol;Kim, Gyoo-Hyung
    • Journal of radiological science and technology
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    • v.41 no.2
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    • pp.97-102
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    • 2018
  • The purpose of this study is to provide the basic data for reducing unnecessary radiation dose to the abdomen and fetus of pregnant women by presenting proper height of shielding protector for efficient abdominal shielding in chest PA examination of Korean pregnant women. The subjects of this study were 288 persons who were eligible for this study among 798 pregnant women who had chest PA examination from January 1, 2015 to December 31, 2016 Retrospective study was performed. Measurements was performed from the apex of the right and left lungs to costophrenic angle of the right and left lungs and to the lowest costophrenic angle among the right and left lungs at the top of the image(this line called Joo's line in this study). The mean of the right and left lung height of pregnant women were 259.09 mm and 263.57 mm, respectively. Also, the average height of the Joo's line designed by the researcher for proper abdominal radiation protection was 322.15 mm. For proper and efficient abdominal radiation protection for pregnant women, it is necessary to adjust the shielding according to the height of the pregnant woman. It is appropriate that the height of the shielding protector should be adjusted so that the upper part of the shield is located at 342.30 mm below from upper part of the detector.

Treatment of retrograde peri-implantitis: seven-year follow-up study (역행성 임플란트 근단병소 주위염(Retrograde Peri-implantitis) 치료의 7년 관찰)

  • Lee, Ju-Youn
    • Journal of Dental Rehabilitation and Applied Science
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    • v.30 no.3
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    • pp.259-264
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    • 2014
  • Retrograde peri-implantitis (RPI) is defined as a clinically symptomatic periapical lesion. RPI is generally accompanied by symptoms of pain, tenderness, swelling and fistula. Several etiologic factors of RPI were possible, residual bacteria would be the main cause of RPI. Various treatment modalities have been introduced: debridement only or a combination of debridement with the grafting material accompanied by a detoxification of the infected implant surfaces, apicoectomy and so on. Although the definitive management methods remain undefined, many favorable clinical results of a treatment of RPI have been published. This case report introduces the 7-year long-term clinical result of the application the principle: implant surface detoxification using saline and chlorhexidine and guided bone regeneration with bone graft material and barrier membrane. If the implant was not mobile, it would be possible to treat RPI according to surgical approach and good results will be maintained over long term.

The Effect of Chlorhexidine on Early Healing Stage of Guided Tissue Regeneration (조직유도재생술의 초기치유에 있어서 클로르헥시딘의 영향)

  • Lee, Jung-Yeon;Han, Soo-Boo;Um, Heung-Sik
    • Journal of Periodontal and Implant Science
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    • v.27 no.4
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    • pp.723-737
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    • 1997
  • 본 연구의 목적은 조직유도재생술의 초기치유시에 구강양치액으로 사용되어지는 0.1% 클로르헥시딘과 0.2% 클로르헥시딘을 사용했을 경우, 양치액을 사용하지 않았을 경우의 세균감염 정도를 비교하는 것이다. 30명의 성인형 치주염에 이환되어진 사람을 대상으로 하였다. 초기치료(Scaling/Root planing/Oral hygiene instruction)를 시행한 후에 한 사람에 한 군데씩 선정하여 2급이나 3급의 치근이개부를 가지고 임상적으로 혹은 방사선학적으로 치간골내낭을 보이지 않는 치아에 통법에 따라 Gore-TexTM를 위치시켰다. 술후 5일간 항생제 (UnasynTM 375mg tablet p.o.tid)를 투여하고 차폐막을 제거할 때까지(4주 혹은 6주) 10명의 환자에게는 0.1% 클로르헥시딘을, 다른 10명의 환자에게는 0.2% 클로르헥시딘으로 구강양치를 하게 하고, 또 다른 10명의 환자에게는 구강양치액을 사용하지 않도록 하였다. 또 1주일에 한번씩 전문가구강위생술식을 실시하였다. 4주나 6주 후에 차폐막을 제거하고 주사전자현미경, 혐기성 세균배양을 이용하여 세균감염정도를 비교하였다. 1. 주사전자현미경으로 관찰시에 0.1% 클로르헥시딘을 사용했을 경우와 0.2% 클로르헥시딘을 사용했을 경우, 클로르헥시딘을 사용하지 않은 경우에 별 차이를 발견할 수 없었다. 2. 혐기성 세균배양시에 0.2% 클로르헥시딘을 사용했을 경우, 0.1%클로르헥시딘을 사용했을 경우보다 적은 수의 세균 수를 보였으나 통계적으로 유의할 만한 차이는 보이지 않았다. 클로르헥시딘을 사용하지 않은 경우에는 다른 두 경우에 비해 통계적으로 유의할 만한 차이를 보였다.(P<0.05) 3. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia를 인지한 경우에는 세 경우 모두 비슷한 비율로 발견되었다.

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Clinical study of guided bone regeneration of extracted socket with PLA/PGA membrane and silk fibroin membrane (PLA/PGA 차폐막과 실크 피브로인 차폐막을 이용한 발치와의 골유도재생술의 비교연구)

  • Hwang, Woo-Jin;Jeong, Seong-Nyum;Kim, Yun-Sang;Pi, Sung-Hee;You, Hyung-Keun;Chung, Chong-Pyoung;Shin, Hyung-Shik
    • Journal of Periodontal and Implant Science
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    • v.39 no.2
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    • pp.129-138
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    • 2009
  • Purpose: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S$^{(R)}$ ) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh$^{(R)}$ ) Methods: 44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. Results: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. Conclusions: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.

The design of blackout curtain for increasing electroplating uniformity of injection molding products (사출물 도금 균일도 증대를 위한 도금조 차폐막 설계)

  • Che, Woo-Seong;Lee, Jong-Keun;Jo, Hae-Yong;Woo, Chang-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.710-713
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    • 2005
  • Recently, in the area of shipbuilding, automobile and electronics, the products which electroplating was applied to are developed and put into practice in the field. The extension of the field of applications electroplated objects is to complex shape and thus the rate of faults in electroplating is being increased in the process of manufacture. On the subject of the plating process in this study, the geometric factor, which influenced electroplating, was extracted by doing a comparative analysis of the findings in the plating bath and the results of performing computer simulation of 3D. Considering these factors, the study on the optimization of designing was conducted to make the plating quantity of plated objects uniform in terms of 3D.

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Hydraulic Experiment on Roughness Coefficient of PE pipe (폴리에틸렌관의 조도계수에 관한 수리모형실험)

  • Dongwoo Ko;Byeong Wook Lee;Jae-Seon Yoon;Hyun-Gu Song
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.288-288
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    • 2023
  • 도로, 철도 등의 횡단통로, 오폐수관로, 지하배수관 등 연약지반에서 상재하중과 부등침하에 의한 파괴 위험을 줄이기 위해 구조적인 안전성과 내구성이 개선된 다양한 관로들이 활용되고 있다. 관은 매설특성에 따라 콘크리트관, 도관, 합성수지관, 덕타일 주철관, 파형강관, 유리섬유 강화 플라스틱과 폴리에스테르수지 콘크리트관 등의 종류로 구분된다(환경부, 2017). 수리설계 시 이러한 관의 단면 규모 결정 및 흐름 특성을 파악하기 위해 관수로 유량측정에 이용되는 Manning의 경험식을 이용하고 있으며, 관로의 주요 재질에 따른 다양한 조도계수가 제시되어 있다. 새로운 재질을 이용하여 제작된 관은 수리실험을 통해 조도계수를 결정하는 것이 바람직하지만, 조도계수 실험은 대규모의 실험시설과 유량공급이 요구되기 때문에 여러 한계가 있다. PE관의 경우, 미국의 ASTM 표준에 의해 저밀도 폴리에틸렌(LDPE), 선형 저밀도 폴리에틸렌(LLDPE), 고밀도 폴리에틸렌(HDPE) 등으로 분류되는데 본 연구에서는 HDPE 재질의 서로 직경이 다른 다중벽관 PE관을 대상으로 조도계수를 결정하기 위한 현장 실규모 수리실험을 수행하였다. 본 실험에서는 식생, 수로의 불규칙성, 수로노선, 침전과 세굴, 장애물, 계절적 변화, 부유물질과 소류사는 무시되며 표면조도, 관의 크기와 형상, 수위와 유량이 조도계수에 영향을 미치는 주요 인자라고 할 수 있다. 수리실험은 실물모형(Prototype)으로 한국농어촌공사 농어촌연구원의 대형수리모형실험장에서 수행되었으며. 길이 24 m, 직경 150 mm의 PE 관은 고정식 개수로, 직경 800 mm의 관은 대형유사순환수로에 각각 설치되었다. 관로의 전면에 차폐막을 설치하여 상류부 수위를 안정시킨 상태에서 실험을 수행하였고, 차폐막으로부터 하류방향으로 약 7 m(측정기준지점), 11 m, 13 m, 15 m, 17 m 떨어진 곳에서 각각 수위와 유속을 측정하였다. 실험 결과, φ150관은 직경대비 수심이 클수록 조도계수가 감소하는 경향이 나타났고, φ800관은 직경대비 수심의 변화에 따른 조도계수의 경향이 크게 드러나지 않았다. 결론적으로 PE관의 조도계수는 수심별로 변화하는 것으로 나타났으며, 특정 수심을 지나면 조도계수가 다시 감소할 것으로 판단된다.

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Effects of conditions for anodization and cyclic precalcification treatments on surface characteristics and bioactivity (양극산화와 석회화 순환처리 조건이 타이타늄 박판의 표면특성 및 생체활성에 미치는 영향)

  • Jang, Yong-Seok;Lee, Kang-Gyu;Jeon, Woo-Yong;Han, A-Lum;Lim, Chung-Ha;Lee, Min-Ho;Bae, Tae-Sung
    • Korean Journal of Dental Materials
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    • v.45 no.4
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    • pp.243-256
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    • 2018
  • The purpose of this study was to investigate the effects of the anodization and cyclic calcification treatment on the surface characteristic and bioactivity of the titanium thin sheet in order to obtain basic data for the production of bioactive titanium membrane. A $30{\times}20{\times}0.08mm$ titanium sheets were prepared, and then they were pickled for 10 seconds in the solution which was mixed with $HNO_3:HF:H_2O$ in a ratio of 12: 7: 81. The $TiO_2$ nanotube layer was formed to increase the specific surface area of the titanium, and then the cyclic calcification treatment was performed to induce precipitation of hydroxiapatite by improvement of the bioactivity. The corrosion resistance test, wettability test and immersion test in simulated body solution were conducted to investigate the effect of these surface treatments. The nanotubes formed by the anodization treatment have a dense structure in which small diameter tubes are formed between relatively large diameter tubes, and their inside was hollow and the outer walls were coupled to each other. The hydroxyapatite precipitates were well combined on the nanotubes by the penetration into the nanotube layer by successive cyclic calcification treatment, and the precipitation of hydroxyapatite tended to increase proportionally after immersion in simulated body solution as the number of cycles increased. In conclusion, it was confirmed that induction of precipitation of hydroxyapatite by cyclic calcification treatment after forming the nanotube $TiO_2$ nanotube layer on the surface of the titanium membrane can contribute to improvement of bioactivity.

Magnetic Shielding Effects of the Electrothermal Shield of a Superconducting Generator with Quick-Response Excitation (속응 여자식 초전도 발전기 열전자 차폐막의 전자 차폐 특성 해석)

  • Lee, H.B.;Bae, D.J.;Kim, S.Wh;Hahn, S.C.;Cha, G.S.;Hahn, S.Y.
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.49-52
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    • 1990
  • In this paper, we proposed a new electrothermal shield model with slits for the purpose of applying to the Superconducting Generator with Quick-Response Excitation. Via experimental and finite element analysis, we compared the magnetic shielding effects of the proposed electrothermal shield model with the conventional one. It is considered that he proposed models meet the needs for the electrothermal shields of the Superconducting Generator with Quick-Response Excitation.

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