• Title/Summary/Keyword: 기계적 체결부

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Characteristic Validation of High-damping Printed Circuit Board Using Viscoelastic Adhesive Tape (점탄성 테이프를 적용한 고댐핑 적층형 전자기판의 기본 특성 검증)

  • Shin, Seok-Jin;Jeon, Su-Hyeon;Kang, Soo-Jin;Park, Sung-Woo;Oh, Hyun-Ung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.5
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    • pp.383-390
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    • 2020
  • Wedge locks have been widely used for spaceborne electronics for mounting or removal of a printed circuit board (PCB) during integration, test and maintenance process. However, it can basically provide a mechanical constraint on the edge of the board. Thus, securing a fatigue life of solder joint for electronic package by limiting board deflection becomes difficult as the board size increases. Previously, additional stiffeners have been applied to reduce the board deflection, but the mass and volume increases of electronics are unavoidable. To overcome the aforementioned limitation, we proposed an application of multi-layered PCB sheet with viscoelastic adhesive tapes to implement high-damping capability on the board. Thus, it is more advantageous in securing the fatigue life of package under launch environment compared with the previous approach. The basic characteristics of the PCB with the multi-layered sheet was investigated through free-vibration tests at various temperatures. The effectiveness of the proposed design was validated through launch vibration test at qualification level and fatigue life prediction of electronic package based on the test results.

A Comparative Study on Power Tool Manufacturers' Products Spec. and Design Development Features - By the Case Study on BOSCH, BLACK&DECKER and KEYANG Electrics- (전동공구 회사의 제품사양별 디자인개발특성 비교연구 -보슈(BOSCH), 블랙앤데커(BLACK&DECKER), 계양전기 사례를 중심으로 -)

  • 채승진
    • Archives of design research
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    • v.17 no.1
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    • pp.383-392
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    • 2004
  • The power tools is the product using working power generated by electric motor. Many companies are manufacturing numerous devices. Main features of tools are included various assembled products, small, light and solid and durable enough to match several standards. Fundamental requirements for the product is excellent performance and convenience for use. The quality of them depends on the equipped motor'(s) capability, accuracy of gear and endurance against worn-out. By adapting the state-of-the-art parts, they could be used in the place from home to heavy industry broadly. They can be classified electronic drills, grinders, saws and sanders families for the household appliances. For industrial tools, bore drill, grinder, polisher, and driver drill are classified as special and high priced group. This study presents the strategy of power tool development of BOSCH, BLACK&DECKER and KEYANG. Their products were analyzed in terms of product line and product mix concept. Then they are examined by design elements, such as color, shape and material for housing. As an analysis method, the image scale parameter and criteria were applied to each company's product.

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A Suvey on Satisfaction Measurement of Automatic Milking System in Domestic Dairy Farm (자동착유시스템 설치농가의 설치 후 만족도에 관한 실태조사)

  • Ki, Kwang-Seok;Kim, Jong-Hyeong;Jeong, Young-Hun;Kim, Yun-Ho;Park, Sung-Jai;Kim, Sang-Bum;Lee, Wang-Shik;Lee, Hyun-June;Cho, Won-Mo;Baek, Kwang-Soo;Kim, Hyeon-Shup;Kwon, Eung-Gi;Kim, Wan-Young;Jeo, Joon-Mo
    • Journal of Animal Environmental Science
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    • v.17 no.1
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    • pp.39-48
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    • 2011
  • The present survey was conducted to provide basic information on automatic milking system (AMS) in relation to purchase motive, milk yield and quality, customer satisfaction, difficulties of operation and customer suggestions, etc. Purchase motives of AMS were insufficient labor (44%), planning of dairy experience farm (25%), better performance of high yield cows (19%) and others (6%), respectively. Average cow performance after using AMS was 30.9l/d for milk yield, 3.9% for milk fat, 9,100/ml for bacterial counts. Sixty-eight percentage of respondents were very positive in response to AMS use for their successors but 18% were negative. The AMS operators were owner (44%), successor (44%), wife (6%) and company worker (6%), respectively. The most difficulty (31%) in using AMS was operating the system and complicated program manual. The rate of response to system error and breakdown was 25%. The reasons for culling cow after using AMS were mastitis (28%), reproduction failure (19%), incorrect teat placement (12%), metabolic disease (7%) and others (14%), respectively. Fifty-six percentages of the respondents made AMS maintenance contract and 44% did not. Average annual cost of the maintenance contract was 6,580,000 won. Average score for AMS satisfaction measurement (1 to 5 range) was 3.2 with decrease of labor cost 3.7, company A/S 3.6, increase of milk yield 3.2 and decrease of somatic cell count 2.8, respectively. Suggestions for the higher efficiency in using AMS were selecting cows with correct udder shape and teat placement, proper environment, capital and land, and attitude for continuous observation. Systematic consulting was highly required for AMS companies followed by low cost for AMS setup and systematization of A/S.