• 제목/요약/키워드: low-precision

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사파이어의 초정밀 연삭 특성 연구 (A Study on the Characteristics of Ultra-Precision Grinding far Sapphires)

  • 김우순;김동현;난바의치
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.422-427
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    • 2003
  • Sapphire have been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing Process.

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이온주입용 정밀고압 발생장치 연구 (A Study of Precision High Voltage Generator for Ion Injection)

  • 유동욱;정창용;백주원;조정구;조기연;김학성;원충연
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 1998년도 전력전자학술대회 논문집
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    • pp.158-161
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    • 1998
  • A precision high voltage generator for ion injection is implemented on HFZVS-PSCI (High Frequency Zero-Voltage-Switching Phase-Shift-Controlled Inverter). Some practical aspects of implementing precision high voltage generator with HFZVS-PSCI, such as a HFHV transformer, multiflier, and precision CR divider are discussed. The results show that the generator under the Phase-Shift-Controller has a fast dynamic response, low ripple voltage, and high accuracy.

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온도 및 유량에 따른 흡입 마취제 전용 기화기와 Goldman 기화기의 isoflurane 농도 변화 (The Isoflurane Concentration of Precision Vaporizer Goldman Vaporizer According to Room Temperature and Carrier Gas Flow Rate)

  • 김성미;장화석;이정선;최치봉;임희란;최준철;김휘율
    • 한국임상수의학회지
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    • 제21권3호
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    • pp.270-275
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    • 2004
  • Anesthetic machines may be equipped with either a precision or nonprecision vaporizer. A precision vaporizer is designed to deliver an exact concentration of anesthetic agent. Goldman vaporizer is a low-flow, closed-circle circuit with a low resistance vaporizer, in circuit. Vaporizers used within circle system(VIC) are not usually temperature compensated and this is generally thought to be a disadvantage. As the volatile agent is vaporized, heat is extracted from the liquid and temperature decreases. This cooling of the liquid leads to a decrease in concentration of the anaesthetic agent delivered by the vaporizer. The purpose of this study is to examine the mechanical consistency of the delivery of isoflurane from Goldman vaporizer and precision vaporizer at various gas flow rates and temperatures. And we first studied isoflurane concentration according to room temperature changes delivered by a Goldman vaporizer and precision vaporizer using different gas flow. The room temperature of $15^{\circ}C,$ $20^{\circ}C,$ $28^{\circ}C$ and fresh gas flow rates of 0.5, 1.0, 1.5, 2.0, 3.0 l/min were used. The inspired agent concentration was measured using a Datex-Ohmeda multigas analyzer. As rose in room temperature, the isoflurane concentration of precision vaporizer approximated the dial setting. On the other hand, at a dial setting concentration of 5.0 percent the delivered isoflurane concentration of precision vaporizer was more than the dial setting in high temperature. The isoflurane concentration of precision vaporizer remained constant despite the increase in temperature. The isoflurane concentration of Goldman vaporizer was increased with rise in room temperature and decreased with rise in gas flow.

자동차용 시트백 커버의 저압사출성형에 관한 연구 (A Study on the Low Pressure Injection Molding of Automotive Seat-back Cover)

  • 고병두;함경춘;장동환
    • 한국정밀공학회지
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    • 제25권12호
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    • pp.100-106
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    • 2008
  • In this paper, the injection molding process of automotive seat-back cover is analyzed in terms of simulation and of experiment. FE analysis was used to obtain molding conditions such as injection pressure, filling pattern, packing, shrinkage. Vacuum system for low pressure injection molding is developed in the experiment. Low pressure injection molded parts have been compared with conventional molded parts in terms of molding quality and mechanical properties. Based on the results, good product and the productivity improvement can be obtained in low pressure injection molding for automotive seat-back cover.