• 제목/요약/키워드: K490

검색결과 1,195건 처리시간 0.028초

강관 및 PHC 매입말뚝의 최적화에 따른 교량기초의 공사비 비교 (Comparison of Construction Costs for Bridge Foundation with Optimization of Steel and PHC Embedded Piles)

  • 윤중만;여규권;김홍연;김동민;김수로
    • 한국지반신소재학회논문집
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    • 제15권4호
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    • pp.71-78
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    • 2016
  • 본 연구에서는 동일한 지층 및 하중조건에서 PHC말뚝을 강관말뚝으로 대체할 경우 말뚝 본수의 변화와 푸팅을 포함한 공사비를 비교하였다. 얕은 풍화암층에 강관말뚝을 지지할 경우 PHC말뚝과 비교하여 12.5%의 본수가 절감되었다. 실 사례로부터 가정된 1.7m 두께의 풍화암층을 통과하여 깊은기초를 연암층에 지지할 경우 일반 및 고강도 강관말뚝은 각각 풍화암층에 설치한 PHC 말뚝 대비 35.7% 및 46.4%, 강관말뚝 대비 26.5% 및 38.8%의 본수가 절감되는 효과가 있는 것으로 나타났다. 푸팅두께가 일정하다고 가정할 경우 풍화암층을 관통하여 연암층에 설치된 일반 및 고강도 강관말뚝은 풍화암층에 설치된 PHC말뚝 대비 각각 12.2% 및 45.4%까지 푸팅의 소요면적을 절감할 수 있는 것으로 나타났다. 이러한 결과를 가지고 말뚝시스템의 전체 공사비를 산정한 결과 풍화암에 지지된 PHC말뚝과 비교할 때 연암층에 설치된 일반 강관말뚝의 비용은 12% 높게 산정된 반면, 이를 고강도 강관말뚝으로 대체하였을 경우는 오히려 16% 절감효과가 있는 것으로 나타났다. 이는 고강도 강관말뚝의 재료비가 상대적으로 높으나 말뚝 본수 및 푸팅면적의 감소로 인한 비용 절감효과가 더 크기 때문이다. 풍화암층 두께를 변화시키며 해석하여 말뚝시스템의 공사비를 비교한 결과 풍화암층 두께가 5m 이하인 조건에서는 PHC말뚝을 풍화암층에 지지하는 것보다 이를 관통하여 연암층에 고강도 강관말뚝을 지지하는 것이 전체 공사비 측면에서 유리한 것으로 나타났다.

대용량 전력변환용 초고전압 NPT IGBT 최적화 설계에 관한 연구 (The Optimal Design of Super High Voltage Planar Gate NPT IGBT)

  • 강이구
    • 한국전기전자재료학회논문지
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    • 제28권8호
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    • pp.490-495
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    • 2015
  • This paper was proposed the theoretical research and optimal design 3,000 V IGBT for using electrical automotive, high speed train and first power conversion. To obtaining 3,000 V breakdown voltage, the design parameters was showed $160{\Omega}{\cdot}cm$ resistivity and $430{\mu}m$ drift length. And to maintain 5 V threshold voltage, we obtained $6.5{\times}10^{13}cm^{-2}$ p-base dose. We confirmed $24{\mu}m$ cell pitch for maintain optimal on state voltage drop and thermal characteristics. This 3,000 V IGBT was replaced to thyristor devices using first power conversion and high speed train, presently.

종아리 근육 마사지가 균형에 미치는 효과 (Effects of Calf Muscle Massage on the Balance)

  • 노효련
    • 한국임상보건과학회지
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    • 제3권4호
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    • pp.490-494
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    • 2015
  • Purpose. The purpose of this study was to evaluate the effects of calf muscle massage on the balance of low extremities and flexibility of both ankles. Methods. The subjects were 16 healthy adults(men 8, women 8). The group was applied effleurage, tapotement, pressure forms of massage on their calf muscles. The intervention was offered during 3 minutes per one leg, to a total of 6 minutes. We assessed their balance and flexibility of both ankles using Functional reaching test(FRT) and One leg standing test(OLST) with trampoline before and after applying massage. Results. In this study, the data shows the ability of FRT and the ability of OLST with trampoline is improved in massage group. Conclusions. These results suggest that massages help to improve the balance of low extremities and the flexibility of both ankles.

Design of Single-Phase Line-Start Permanent Magnet Motor Using Equivalent Circuit Method

  • Kwon, Sun-Hyo;Lee, Chul-Kyu;Kwon, Byung-Il
    • Journal of Electrical Engineering and Technology
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    • 제1권4호
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    • pp.490-495
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    • 2006
  • In this research, the design procedure and the design method of a single-phase line-start permanent magnet motor (LSPM) are proposed. In the design procedure, the permanent magnet is designed first and the windings and capacitors are designed later. As well, the points of design of each design parameter are explained. In the design of the single-phase LSPM, the equivalent circuit method is combined with the finite element method (FEM) because it has a shorter analysis time than FEM. The 400 watts single-phase LSPM is designed and manufactured. The characteristics of the manufactured single-phase LSPM are analyzed and experimented. From the analysis result and the experiment result, it is verified that the design procedure and the design method of the single-phase LSPM is valid.

알루미늄 분말 합금의 반응고 미세조직 특성 연구 (A Study on the Characteristics of Microstructures in the Semi-solid State of Aluminum Powder Alloys)

  • 이상용
    • 열처리공학회지
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    • 제21권4호
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    • pp.205-212
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    • 2008
  • Characteristics of microstructures, mechanical properties and formability of two Al-20Si-5Fe-2Ni alloys produced by gas atomizing (P/M) and spray forming (S/F) respectively were compared at temperatures up to $560^{\circ}C$. Room temperature hardness values and tensile strengths of both alloys were increased in accordance with temperature after heat treatment above $300^{\circ}C$. The highest values of hardness and tensile strength of both alloys were obtained at $490^{\circ}C$. It was interpreted that increase in hardness and tensile strength according to heating temperature between $300{\sim}490^{\circ}C$ was mainly related to increase in internal stress between Al matrix and reprecipitated particles. S/F alloys showed better formability and wear property than P/M alloys due to the homogenity of microstructures above $300^{\circ}C$.