• 제목/요약/키워드: Phase explosion

검색결과 100건 처리시간 0.023초

액중 전기선폭발법으로 제조된 구리 나노콜로이드의 특성 평가 (Evaluation of Cu nano-colloid prepared by electrical wire explosion in liquid phase)

  • 윤재철;양상선;유지훈
    • 한국입자에어로졸학회지
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    • 제6권1호
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    • pp.37-46
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    • 2010
  • Cu nano-colloid was prepared by wire electric explosion process under de-mineralized water and anhydrous ethanol. To control the properties of Cu nano-colloid, experimental conditions such as diameter of Cu wire and applied voltage were changed. The optimal Cu nano-colloid was prepared when the 0.1mm diameter of Cu wire with the applied voltage of 2000 V was used. The shape of Cu particles in colloid was spherical and the XRD result revealed that the phase of Cu particles was cubic phase. About 20nm Cu nanoparticles with high crystallinity were successfully prepared using wire explosion process under anhydrous ethanol and they showed more than 100 hours dispersion stability.

Morphology, Phase Contents, and Chemical Composition of Nanopowders Produced by the Electrical Explosion of Tin-Lead Alloy Wires

  • Kwon, Young-Soon;P. Ilyin, Alexander;V. Tichonov, Dmitrii
    • 한국분말재료학회지
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    • 제10권3호
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    • pp.157-160
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    • 2003
  • Phase contents and elemental composition of ultradispersed powders obtained by the electrical explosion of tin-leadalloy powders are investigated. It is demonstrated that during the explosion and subsequent cooling, surface layers of powder particles are enriched in lead compared to the initial alloy. The thermal stability of powders oxidizing in air is also investigated.

액체의 상폭발 과정에 의한 펄스 레이저 용발률의 증진 (Enhancement of Pulsed-Laser Ablation by Phase Explosion of Liquid)

  • 김동식;이호
    • 대한기계학회논문집B
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    • 제25권11호
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    • pp.1483-1491
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    • 2001
  • Enhancement of pulsed-laser ablation by an artificially deposited liquid film is presented. Measurements of ablation rate, ablation threshold, and surface topography arc performed. Correlation between material ablation and photoacoustic effect is examined by the optical beam deflection method. The dependence of ablation rate on liquid-film thickness and chemical composition is also examined. The results indicate that photomechanical effect in the phase explosion of liquid is responsible for the enhanced ablation. The low critical temperature of liquid induces explosive vaporization with localized photoacoustic excitation in the superheat limit and increases the ablation efficiency. Experiments were carried out utilizing a Q-swiched Nd:YAG laser at near-threshold laser fluences with negligible plasma effect (up to ∼100 MW/cm$^2$).

고출력 레이저 어블레이션에 의한 실리콘 가공시 발생하는 상폭발 현상에 관한 연구 (Study on the phase explosion phenomena during high power laser ablation of silicon)

  • 정성호
    • 한국레이저가공학회지
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    • 제3권3호
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    • pp.39-45
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    • 2000
  • The volume and depth of the craters produced on silicon samples during high power laser ablation show a strong nonlinear change as the laser irradiance increases across a threshold value, approximately 2.2$\times$10$\^$10/ W/㎠. Time-resolved shadowgraph images of the ablation plume reveal the ejection of large particulates from the sample for laser irradiance above the threshold, with a time delay of about 300-400 ㎱. The numerically estimated thickness of the superheated liquid layer, considering the transformation of liquid metal into liquid dielectric near the critical state, agrees with the measured agrees with crater depths. It is suggested that a phase explosion of the deep superheated liquid layer near the critical state is responsible for the measured sudden increase of crater volume and the ejection of large particulates.

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풍량 및 운전시간 제어 방폭 배풍기 인버터 단자함 개발에 관한 연구 (A Study on the development of Explosion-proof type's the terminal box of the ventilator with the control of wind volume and operating time)

  • 유동주
    • 융합정보논문지
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    • 제8권6호
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    • pp.187-192
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    • 2018
  • 본 논문은 풍량 및 운전시간을 제어할 수 있는 방폭 타입 배풍기의 인버터 단자함 연구에 관한 것이다. 국내에서는 열악한 환경에서 작업 시에 풍량 및 운전 시간을 조정할 수 있는 배풍기가 없는 실정이다. 유해가스 및 폭발 위험성이 있는 환경에 적정한 방폭 배풍기의 운전 시간과 풍량을 제어할 수 있는 방폭 단자함을 제작하는 것이 목적이다. 2개의 방폭형 스위치를 사용하여 운전시간을 1 시간, 3 시간, 그리고 연속 시간으로 운전할 수 있도록 하였고, 유도전동기 회전 속도는 2000rpm, 2600rpm, 그리고 3000rpm으로 3 단계로 설정하여 풍량 제어하였다. 실험한 모터는 1/2 마력 3상 유도전동기 사용하였으며 풀 브리지 인버터를 제작하여 원하는 풍량과 운전시간 설정할 수 있도록 연구하였다.

전기선폭발법에 의한 Cu-Ni-P 합금 나노 분말 제조 (Cu-Ni-P Alloy Nano Powders Prepared by Electrical Wire Explosion)

  • 김원백;박제신;서창열;이재천;김정환;오용준
    • 한국분말재료학회지
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    • 제14권2호
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    • pp.108-115
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    • 2007
  • Cu-Ni-P alloy nano powders were fabricated by the electrical explosion of electroless Ni plated Cu wires. The effect of applied voltage on the explosion was examined by applying pulse voltage of 6 and 28 kV, The estimated overheating factor, K, were 1.3 for 6 kV and 2.2 for 28 kV. The powders produced with pulse voltage of 6 kV were composed of Cu-rich solid solution, Ni-rich solid solution, and $Ni_3P$ phase. While, those produced with 28 kV were complete Cu-Ni-P solid solution and small amount of $Ni_3P$ phase. The initial P content of 6.5 at.% was reduced to 2-3 at.% during explosion due to its high vapour pressure.

수중 폭발 시뮬레이션을 위한 경계 요소법 기반의 수치 해석 기법 연구 (A Study on BEM-Based Numerical Simulation Technique for Underwater Explosions)

  • 정준모;이재빈
    • 대한조선학회논문집
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    • 제57권5호
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    • pp.271-277
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    • 2020
  • Recoverability and vulnerability of navy ships under underwater explosion are critical verification factors in the acquisition phase of navy ships. This paper aims to establish numerical analysis techniques for the underwater explosion of navy ships. Doubly Asymptotic Approach (DAA) Equation of Motion (EOM) of primary shock wave and secondary bubble pulse proposed by Geers-Hunter was introduced. Assuming a non-compressive fluid, reference solution of the DAA EOM of Geers-Hunter using Runge-Kutta method was derived for the secondary bubble pulse phase with an assumed charge conditions. Convergence analyses to determine fluid element size were performed, suggesting that the minimum fluid element size for underwater explosion analysis was 0.1 m. The spherical and cylindrical fluid domains were found to be appropriate for the underwater explosion analyses from the fluid domain shape study. Because the element size of 0.1 m was too small to be applied to the actual navy ships, a very slender beam with the square solid section was selected for the study of fluid domain existence effect. The two underwater explosion models with/without fluid domain provided very similar results in terms of the displacement and stress processes.

폭발이 구조물에 미치는 영향 (Effects of Explosion on Structures)

  • 윤용균
    • 화약ㆍ발파
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    • 제37권4호
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    • pp.10-16
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    • 2019
  • 충격파나 압력파가 구조물에 미치는 영향을 평가하기 위해서는 과압, 양의 압력 지속시간, 충격량에 대한 정보가 필요하다. 본 연구에서는 증기운 폭발 해석에 효과적인 다중에너지법을 적용하여 과압 및 양의 압력 지속 시간을 결정하였다. 영국 Nypro 화학회사에서 발생한 싸이클로헥산 증기운 폭발 사고에서 추정된 총 폭발열을 기반으로 폭발원으로부터 40, 80, 120, 160, 200, 240, 280, 320, 360(m) 이격된 지점에서의 과압, 양의 압력 지속시간을 평가하였다. 거리에 따라 과압은 지수적으로 감소하는 것으로 나타났고, 양의 압력 지속시간은 거의 선형적으로 증가하는 것으로 나타났다. 상기의 각 거리에서 구한 과압 및 충격량을 이용하여 각 거리에서의 구조물의 손상 확률을 평가하기 위해서 프로빗 함수를 사용하였다. 손상 확률을 평가한 결과 120m 이내 지점에서는 붕괴의 가능성이 크고, 240m 이내에서는 심각한 구조물의 손상이, 구조물의 가벼운 손상과 유리창 파손은 전 범위에 걸쳐서 발생하는 것으로 나타났다.

상 변화와 인터페이스 이론을 이용한 고에너지물질의 반응연구 (Study of energetic materials using phase change and interface theory)

  • 김기홍;김학준;김형원;여재익
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년도 제31회 추계학술대회논문집
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    • pp.60-63
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    • 2008
  • 고에너지 물질의 상변화는 연소과정에서 발생하는 필연적으로 중요한 요소이다. 연소과정에서 발생한 고온, 고압의 가스는 주변의 물질과 상호작용을 통해 복잡한 현상을 일으키게 된다. 본 연구에서는 고에너지 물질의 상변화를 해석을 하기 위한 기초 연구로 상변화 변수를 이용하여, 증기 폭발을 해석하였다.

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방폭설비 성능유지 실태분석을 통한 관리방안 연구 (A Study on the Management Plan through Performance Maintenance Analysis of Explosion-proof Facilities)

  • 권용준;변정환
    • 한국안전학회지
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    • 제35권2호
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    • pp.8-16
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    • 2020
  • In Article 311 of the Regulation on Occupational Safety and Health Standards requires the use of Korean Industrial Standards Act in accordance with the Industrial Standardization Act. However, the classification, inspection, maintenance, design, selection, and installation of explosion hazard locations for explosion and explosion prevention and internalization of 'safety' in the performance maintenance phase of electrical machinery and equipment There is no technical and institutional management plan for remodeling and alteration. Analysis of actual conditions and problems related to the installation, use, and maintenance of explosion-proof equipment, comparative analysis of domestic and international technical standards and systems, technical, institutional and administrative systems and systems related to installation, use, and maintenance of explosion-proof equipment, technical personnel and qualifications, etc. It is to propose legislation, system improvement, and technical standard establishment related to the maintenance of explosion-proof facility performance through improvement of the necessity and feasibility study for establishment of the legal status of the management site and management plan. As technical measures, KS standard revision (draft), KOSHA guide (draft) and explosion-proof facility performance maintenance manual were presented. In addition, the institutional management plan proposed the revised rule on occupational safety and health standards, the revised rule on the restriction of employment of hazardous work, and the manpower training program related to the maintenance of explosion-proof facilities and the qualification plan. Enhance safety at the installation, use, and maintenance stage of explosion-proof structured electrical machinery. It is expected to be used to classify explosion hazards, select related equipment, and to update and standardize standards related to installation, use and maintenance.