• Title/Summary/Keyword: Reasonance

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A Study on the Electronic Development for Fluorescent Lamp (형광등용 전자식 점등기 개발에 관한 연구)

  • Park, Jin-Hyung;Sea, Jin-Yun;Jang, Yong-Hae;Sin, Sea-Yun;Baek, Hyung-Lae;Go, Geum-Bea
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.300-302
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    • 2003
  • Fluorescent lamp converts electrical energy Into light energy. Generally we use both electronic ballast and glow starter method in the house. We developed 40W electronic starter and its characteristic is verified by experiments. The efficiency of ballast is improved by using the LC Parallel reasonance circuit at input stage and LC series reasonance circuit at out-put stage.

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생체적합성 유ㆍ무기 나노 입자를 이용한 조영제의 최근 개발 동향

  • 조선행;김문석;강길선;김정안;이해방
    • Polymer Science and Technology
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    • v.15 no.4
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    • pp.438-448
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    • 2004
  • 최근 노인 인구가 증가함에 따라 뇌혈관질환, 암 질환이 증가하고 있으며, 생활환경의 변화에 따른 성인병 발병 연령이 점차 낮아져 건강에 대한 관심이 증가하고 있다. 이에 따른 병의 조기 발견을 위한 여러 진단방법이 발전되고 있으며 최첨단 진단방법인 핵 자기공명 단층촬영술 (MRI, magnetic reasonance image)의 사용이 증가되고 있다.(중략)

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New HVDC Interaction between AC networks and HVDC Shunt Reactors on Jeju Converter Stations

  • Kim, Chan-Ki;Kwon, Young-Hun;Jang, Gil-Soo
    • Journal of Power Electronics
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    • v.7 no.3
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    • pp.233-237
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    • 2007
  • This paper deals with the new HVDC interaction which was observed in the Jeju-Haenam HVDC system. The interaction is not from a system malfunction or controller loop problem but from the change of AC network scheme and the network operating condition. We have found that the interaction is caused by the voltage oscillation between synchronous compensator and HVDC shunt reactor. We analyzed the cause of the interaction and suggested a solution.

A study on an Electronic Ballast Using LC Reasonance Circuit for Fluorescent Lamps (LC공진회로를 이용한 형광등용 전자안정기에 관한 연구)

  • 최수현;조성권;정봉만;한수빈
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.2 no.3
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    • pp.39-46
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    • 1988
  • 고효율을 갖는 고주파점등용 전자식 안정기 개발에 대한 연구이다. 안정기 입력단에 LC병렬공진회로를 연결하고 출력단에서 LC직렬공진회로를 이용함으로써 효율을 향상시켰다. 안정기에 대한 회로상의 주요 착상을 중심으로 동작을 설명하였으며 실용회로를 구성하여 성능을 실험하였다. 그 결과 개발된 전자식안정기의 40W 형광램프에 적용시 형광등과 안정기의 총 소비전력은 35W였으며 이는 기존 국내의 전자식 안정기의 적용시 소비전력에 대해 10%가 향상된 것이다. 고조파특성 또한 기존 자기식안정기 수준으로 향상되었다.

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Spinal Epidural Hematoma Occuring after Bloody Tap during Epidural Catheter for Cancer Pain Control -A case report- (암성통증치료를 위한 경막외카테테르 거치술중 혈성천자로 발생한 경막외혈종 -증례 보고-)

  • Woo, Sung-Chang;Cha, Dong-Suk;Kang, Keon;Kim, Young-Ki
    • The Korean Journal of Pain
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    • v.11 no.1
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    • pp.160-164
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    • 1998
  • We report a case of epidural hematoma occuring after bloody tap during epi-dural catheter for cancer pain control in thrombocytopenic patient. Two hours after epidurl puncture, patient experienced severe back pain and numbness of both legs. Following day, patient complained of motor paralysis and urinary difficulty. Diagnosis utilizing magnetic reasonance imaging, showed epidural hematoma extending from $T_{11}$ to $T_{12}$. Thrombocytopenia prevented surgical intervention. Therefore we restored conservative therapy with packed red cell, platelet concentration, steroid and hemostatic, which provided complete neurologic recovery, spontaneously over several days without surgical intervention.

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Immobilization of Lum,brokinase on the Surface of Polyurethane by using the Photoreactive Poly(acrylic acid) (광반응성 poly(acrylic acid)를 이용한 Lumbrokinase 의 polyurethane 표면 고정화 방법에 관한 연구)

  • 김현정;류은숙;김종원;민병구
    • Journal of Biomedical Engineering Research
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    • v.20 no.6
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    • pp.547-553
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    • 1999
  • 생체재료로 사용되는 polyurethane(PU) 표면에 항혈전성 lumbrokinase(LK)를 고정함으로써 생체적합성을 향상시키고자하였다. 먼저 LK를 PU 표면에 고정하기 위한 가교제로서 4-azidoaniline hydrochloride와 poly(acrylic acid)를 이용하여 4-azidophenyl 작용기가 amido 결합으로 치환된 수용성, 광반응성 poly(acrylic acid)(PPa-II)를 합성하였다. H-nuclear magnetic reasonance spectrum(500MHz H-NMR)의 6-7 peak와 infrared spectrum (FT-IR) 의 2125.48 cm peak으로부터 PPA-II의 합성을 지원하였다. EH한 4-azidophenyl 작용기가 poly(acrylid acid) 잔기에 치환된 정도는 UV/VIS adpectrophotometric spectrum을 확인한 결과 11~14%임을 알 수있었다. 0.5 1및 5% PPA-II를 각각 광반응하여 얻은 PU는 39.5, 161.8 및 181.5 nmole/$\textrm{cm}^2$의 농도로 표면에 carvoxyl 작용기가 유도되었음을 알 수있었다. 0.05M KH2PO4 (pH 4.5) 용액에서 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide(EDC)를 촉매로 사용하여 LK를 PU표면에 amido 공유결합으로 고정하였으며, 이것은 지속적인 fibrinolytic 활성도를 보였다. PPA-II를 이용한 표면 개질 방법은 수용성 반응조건에서 이루어진다는 점과 광반응을 이용함으로써 특정부위에서의 표면개질이 가능하다는 점에서 그 응용가치가 크며 아울러 PU의 생체적합성을 향상시킬 수 있는 방법으로서 판단된다.

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Estimation of Mechanical Properties of Concrete in Early Age by Resonance Frequency Test (공명주기식 동탄성계수를 이용한 초기재령 콘크리트의 역학적 성질 예측)

  • Kim, Jin-Keun;Kiim, Hoon;Noh, Jae-Ho
    • Magazine of the Korea Concrete Institute
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    • v.7 no.5
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    • pp.164-171
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    • 1995
  • Drying shrinkage and hydration heat are important factors on the initiation of the crack in con crete at early age. Therefore, the stress caused by hydration heat and drying shrinkage should be .analyzed to predict whether the crack occurrs or not. And, mechanical properties of early age concrete is also required for the predicting crack formation In this study, non-destructive test method of resonance frequency was used to find the relation between dynamic modulus and mechanical properties of concrete in early age. Test results were compared with existing equations, and a new equation based on test. results in this study and other data was also proposed

The Effect of Solvents on the Formation of Complexes of Benzene with Iodine and with Iodine Monochloride (벤젠과 요오드 또는 일염화요오드 사이의 錯物에 대한 용매의 영향)

  • Choi, Sang-Up;Lee, Bu-Yong
    • Journal of the Korean Chemical Society
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    • v.9 no.4
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    • pp.161-168
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    • 1965
  • The effect of solvents on the stabilities of the $C_6H_6{\cdot}I_2$ complex and the $C_6H_6{\cdot}ICl$ complex has been investigated through ultraviolet spectrophotometric measurements. The equilibrium constants obtained at room temperature for the formation of $C_6H_6{\cdot}I_2$ complex are 0.090, 0.216 and 0.328$ lmole^{-1}$ in chloroform, cyclohexane and n-hexane, respectively. The corresponding equilibrium constants at room temperature for $C_6H_6{\cdot}ICl$ complex are 0.125, 0.676 and 0.689 $lmole^{-1}.$ These results indicate that the stabilities of the two complexes increase with decreasing dielectric constants of the solvents used, the increase in stability being more rapid in the $C_6H_6{\cdot}ICl$ complex than in the $C_6H_6{\cdot}I_2$ complex. This may support the conclusion that the dative ionic structures, $C_6H_6^+{\cdots}I_2^-$ and/or ($C_6H_6I)^+{\cdots}Cl^-,$ play important roles on the reasonance stabilization of both the $C_6H_6{\cdot}I_2$ complex and the $C_6H_6{\cdot}ICl$ complex, the roles being more important in the latter complex than in the former complex.

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