• 제목/요약/키워드: safety properties

검색결과 2,752건 처리시간 0.032초

전자파 차폐성능 향성을 위한 건축용 블록의 형상 연구 (A Study of Block Structures for Improving the Electromagnetic Shielding Properties)

  • 임계재
    • 한국정보전자통신기술학회논문지
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    • 제5권4호
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    • pp.175-179
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    • 2012
  • 본 연구에서는 콘크리트로 제조된 블록이나 타일의 형상을 변형하여 이동통신 및 ETC 주파수 대역에서 우수한 전자파 차폐 성능을 최대화할 수 있는 방안을 제안하였다. 측정 결과, 최적 설계된 블록의 형상은 약 30 dB의 차폐 성능을 나타내어 전자파 인체 안전성이나 전자파 간섭 문제의 대책 제품으로 사용 가능할 것이다.

건식 열화처리가 FRP의 표면 열화와 유전특성에 미치는 영향 (The Influence of Dry Treatments on the Surface Degradation and Dielectric Properties in Fiber Reinforced Plastics)

  • 이백수;이덕출;정의남;유도현;김종택
    • 한국안전학회지
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    • 제13권3호
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    • pp.88-95
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    • 1998
  • In this paper, we investigated the change of wettability, surface potential decay and dielectric properties caused by ultraviolet-treated, thermal-treated and discharge-treated FRP(fiber reinforced plastics) respectively for finding out the influence of dry treatments effected to electrical characteristics on the surface of polymer composites. For the change of wettability, the contact angle of thermal-treated specimen with the high temperature of $200^{\circ}C$ increased. But that of UV-treated and discharge- treated specimen decreased. The characteristic of surface potential decay shows the tendency of the remarkable decrease on UV-treated and discharge-treated specimens, but no difference on thermal-treated specimen compared with untreated one. Also, for the dielectric properties, it shows the increase at large on the treated specimens and especially, the remarkable increase on thermal-treated one.

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볼트 결합부 풀림에 관한 마찰 특성 (제 I 보 : 나사 마찰 실험) (The Friction Properties on the Loosening of Bolted Joints (I: Thread Friction Experiments))

  • 박태원;신귀수
    • 한국안전학회지
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    • 제18권2호
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    • pp.1-5
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    • 2003
  • By using an approach developed to determine the torque-tension relationship for bolted joints, frictional properties of several typical bolted joints were studied experimentally. The specific property by bolted joints certify that the most significant influence of materials and bearing surface condition. Experiments on thread friction shows that prevailing torque nuts with distorted threads provide benefit for preventing self-loosening of the nut. Repeated tightening-loosening generally increases frictions in a bolted joint. It was noted that the data scatter of the experimental results of frictions in a belted joint may overshadow the influence of size. speed, and contact positions. The results from the experimental investigation will help to better design bolted joints.

폴리올레핀계 폐플라스틱/복합filler 성형체의 난연성 및 기계적 물성 연구 (Flame Retardancy and Mechanical Property of Recycled Polyolefinic Plastic Composites with Hybrid fillers)

  • 강영구;송종혁
    • 한국안전학회지
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    • 제18권2호
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    • pp.56-63
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    • 2003
  • Flame retardancy and mechanical properties of recycled polyolefinic plastics/inorganic filler composite systems were investigated by using several inorganic flame retardants such as magnesium hydroxide and slag powder generated electro arc furnace Compatibilizer user each maleic anhydride functionalized polyethylene (PE-g-MAH) and polypropylene(PP-g-MAH) or used mixture of these. The effect of polymeric compatibilizers on the properties of composites was studied by tensile and impact test, differential scanning calorimetry, in the changed fracture mechanism. The improved adhesion was particularly reflected in the mechanical properties. The flame retardancy of composites was examined by measuring limiting oxygen index(LOI, ASTM D2863), smoke density(ASTM D2843) and vertical burning test(UL94). Regarding the flame retardant effect, the EAF slag powder is behaving as synergists as they are only active in the presence of magnesium hydroxide.

목재산업 작업장의 부유분진에 관한 연구

  • 이내우;이병선
    • 한국산업안전학회:학술대회논문집
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    • 한국안전학회 1998년도 추계 학술논문발표회 논문집
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    • pp.89-92
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    • 1998
  • Tannins are complex polyphenolic substances present in plants. They may be classified as either hydrolysable or condensed tannins, and extracts of the latter type have displayed carcinogenic properties in animal studies (Hausen, 1981). The International Agency for Research on Cancer has determined that exposure to airborne wood dust, especially hardwood dust during furniture manufacture, is a cause of sino-nasal cancer, notably nasal adenocarcinoma. (omitted)

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Effect of Different Tumbling Marination Methods and Time on the Water Status and Protein Properties of Prepared Pork Chops

  • Gao, Tian;Li, Jiaolong;Zhang, Lin;Jiang, Yun;Yin, Maowen;Liu, Yang;Gao, Feng;Zhou, Guanghong
    • Asian-Australasian Journal of Animal Sciences
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    • 제28권7호
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    • pp.1020-1027
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    • 2015
  • The combined effect of tumbling marination methods (vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) and effective tumbling time (4, 6, 8, and 10 h) on the water status and protein properties of prepared pork chops was investigated. Results showed that regardless of tumbling time, CT method significantly decreased the muscle fiber diameter (MD) and significantly increased the total moisture content, product yield, salt soluble proteins (SSP) solubility, immobilized water component (p<0.05) compared with IT method. With the effective tumbling time increased from 4 h to 10 h, the fat content and the MD were significantly decreased (p<0.05), whereas the SSP solubility of prepared pork chops increased firstly and then decreased. Besides, an interactive effect between CT method and effective tumbling time was also observed for the chemical composition and proportion of immobilized water (p<0.05). These results demonstrated that CT method of 8 h was the most beneficial for improving the muscle structure and water distribution status, increasing the water-binding capacity and accelerating the marinade efficiency of pork chops; and thus, it should be chosen as the most optimal treatment method for the processing production of prepared pork chops.