• Title/Summary/Keyword: lead free

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MO Theoretical Studies on Organic Accelerators of Vulcanization (유기 가황촉진제에 관한 분자 궤도론적 연구)

  • Ikchoon Lee
    • Journal of the Korean Chemical Society
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    • v.15 no.6
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    • pp.359-366
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    • 1971
  • The extended Huckel calculations on five organic accelerators of vulcanization have been carried out. Various MO quantities e.g., electron populations and AO coefficients, are used to explain accelerator reactivity of the compounds. Results of these analyses lead us to support free radical mechanism of acceleration in vulcanization.

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Standardization of reliability specification for lead free solder paste (무연솔더페이스트의 신뢰성 규격 제정)

  • 강종태;박재현;김영섭;이중주
    • Proceedings of the KWS Conference
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    • 2004.05a
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    • pp.73-74
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    • 2004
  • Sn-Pb계 유연 솔더는 오랜 기간동안 전자기기의 가장 유효한 접합재료로 사용되어 왔다 그러나, 근년. 솔더를 사용한 전자기기의 폐기 시에 산성비에 의해 솔더중에 함유된 납(Pb) 성분이 용출되어 지하수를 오염시키고 이것이 인체에 흡수되면 지능저하, 생식기능저하 등 인체에 해를 미치는 환경오염 물질로 지적되고 있다. (중략)

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Development of polishing tool system for robot (로보트용 금형 연마 공구 시스템의 개발)

  • 박종오;이대엽
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.190-193
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    • 1990
  • Die finishing (polishing and lapping) after NC machining is characterized as one bottleneck process for reducing lead time. For automation of this typical manual work, a flexible polishing tool system using industrial robot has been developed. This tool system has three principal functions in order to achieve reduction of waviness, 3 D.O.F. compliance and constant pressure structure. This polishing tool shows that adaptability to free form surface is increased and programmability to various areas of die surface is also acquired.

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Introduction of Reliability Test Technology for Electronics Package (전자패키지 신뢰성 평가기술의 개요)

  • Tanaka, Hirokazu;Kim, Keun-Soo
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.1
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    • pp.1-7
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    • 2012
  • Reliability technology has been expected to grow rapidly for new types of electronic equipments. We have selected several reliability issues in electronic package to be reviewed. This paper will provide a view of the current state of technological progress in reliability of electronic package in Japan, and will discuss future prospects for the technology.

Effect of New Improved Technology of Silkworm Bombyx mori L. Rearing on the Egg Production Capacity

  • Greiss, H.;Tzenov, P.;Grekov, D.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.3 no.2
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    • pp.135-139
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    • 2001
  • Experiments were held in Egypt to test a new Package of practices for commercial cocoon production, including adding secondary macro and micronutrients to the mulberry garden, disease free rearing regime, low temperature rearing in young instars and natural mounting fur silkworms. This package for seed silkworm rearing lead to increase in fecundity by 67-121eggs (15.12-26.22%) and yield of standard boxes per 1 parent egg boxes by 57-58 egg boxes(48.33-51.66%) respectively in comparison th the traditional cocoon production technology.

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Preparation and characterization of electroplated lead-free solder alloy (전해 도금을 이용한 무연 솔더 합금 박막 제조)

  • Lee, Hui-Cheol;Jo, Jin-Gi
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.136-136
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    • 2012
  • 최근 전자제품의 크기가 소형화, 고성능화 되어감에 따라 전자제품을 구성하는 부품 크기도 작아지고, 배선의 피치 또한 미세화 되고 있다. 따라서 패키징 과정도 미세하고 정확한 제어를 필요로 하게 되었으며, 전해도금을 통한 정밀 패키징 공정이 도입되고 있다. 그러나 기존에는 패키징용 메인기판과 부품을 연결하는 솔더는 기존의 Sn-Pb 조성의 납을 포함하는 소재가 사용되었다. 하지만 납의 환경적 문제에 의해 사용을 금지하게 된 상태로 이를 대체하기 위한 무연 조성의 솔더가 연구되고 있다.

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Finite strain nonlinear longitudinal vibration of nanorods

  • Eren, Mehmet;Aydogdu, Metin
    • Advances in nano research
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    • v.6 no.4
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    • pp.323-337
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    • 2018
  • The nonlinear free vibration of a nanorod subjected to finite strain is investigated. The governing equation of motion in material configuration in terms of displacement is determined. By means of Galerkin method, the Fourier series solutions satisfying some typical boundary conditions are determined. The amplitude-frequency relationship and interaction between the modes are studied. The effects of nonlocal elasticity are shown for different length of nanotubes and nonlocal parameter. The results show that nonlocal effects lead to additional internal modal interaction for nanorod vibrations.