• Title/Summary/Keyword: Chang-Ki(張機)

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Precision Validation of GPS Precipitable Water Vapor via Comparison with MWR Measurements (MWR 관측치와 비교를 통한 GPS 가강수량 정밀도 검증)

  • Ha, Jihyun;Park, Kwan-Dong;Chang, Ki-Ho;Yang, Ha-Young
    • Atmosphere
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    • v.17 no.3
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    • pp.291-298
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    • 2007
  • The precipitable water vapors (PWVs) obtained from Global Positioning System (GPS) and Microwave Radiometer (MWR) measurements have been compared for validation of precision of the GPS PWV at Daegwallyoung station for 21 days from Sep. 30 to Oct. 20, 2006. The GPS PWV is estimated using the delay of GPS signals due to the water vapor in the atmosphere with a local mean temperature equation, called HP model, and the MWR PWV by the combinational radiance observation of two channels (23.8 and 31.4 GHz). During the co-observation period, the MWR and GPS PWV show a similar trend, and the bias between the PWVs is 1.7 mm on average. When the bias is removed, the PWV of GPS gives good agreement with that of MWR, having about 1 mm for both the standard deviation and RMS error between the GPS and MWR PWV.

A Study on AC Loss in the Two-parallel Solenoid Coil using Multi-stacked conductors (적층형 도체를 이용한 2병렬 솔레노이드 코일의 교류손실 연구)

  • Hwang, Young-Jin;Choi, Suk-Jin;Chang, Ki-Sung;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.820_821
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    • 2009
  • 전력기기는 일반적으로 상용주파수인 60 Hz의 교류 전원하에서 운용된다. 따라서 고온초전도체를 전력기기에 응용하는데 있어 교류전류나 교류자장에 의한 교류손실 발생 문제는 전력기기의 경제적 운용과 관련하여 중요하게 부각되어 왔다. 또한 고온초전도체에서 발생하는 교류손실은 에너지의 열적 변환으로 인한 냉동부하 문제와도 관련되어 있기 때문에 전력기기의 안정적인 운용을 위해서도 반드시 연구되어야 할 부분이다. 특히 변압기와 같이 유도형 권선이 필요한 전력기기의 경우에는 무유도 권선 형태가 적용되는 다른 전력기기에 비해 교류 손실의 크기가 매우 크기 때문에 이를 줄이기 위한 방안에 대한 연구가 다각도로 이루어지고 있다. 본 연구에서는 임계전류와 인덕턴스의 크기는 동일하지만 권선 형태를 다르게 할 수 있는 유도형 솔레노이드 코일을 제작하였다. 그리고 제작된 솔레노이드 코일의 병렬연결 구조를 달리하여 각각의 구조에 대한 교류손실의 차이를 측정하고 분석하였다. 그리하여 측정된 결과를 토대로 고온초전도 선재를 이용한 솔레노이드 코일에서 교류손실을 줄이기 위한 구조적 방안을 제시하고자 한다.

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Inorganic Components and Some Physical Properties of Sap from Sponge-gourd(Luffa cylindrica L.) as Affected by Collection Time (채취시기(採取時期)에 따른 수세미오이(Sponge-gourd; Luffa cylindrica L.) 수액(樹液)의 무기성분(無機成分) 및 물리적(物理的) 성질(性質)의 특성(特性))

  • Park, Jong-Sang;Lee, Jin-Il;Chang, Ki-Woon
    • Applied Biological Chemistry
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    • v.39 no.1
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    • pp.67-69
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    • 1996
  • Some physical properties and inorganic components of sap from sponge-gourd(Luffa cylindrica L.) were investigated for their changes affected as collection time. Huter valves, pH, turbidity and viscosity of the sap were not different. pH value was indicated at slightly alkalinity and decreased by culturing period. Potassium, calcium and magnesium were major inorganic components of the sap and podium, zinc and iron were minor components. Copper was not detected in open culturing and also manganes way not detected in all samples.

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The Effect of Higenamine upon the Interval-Strength Relationship in Isolated Rabbit Heart (적출 가토 심장에 있어서 수축빈도-수축력 상관관계에 대한 Higenamine의 강심 효과)

  • Chang, Ki-Churl
    • The Korean Journal of Pharmacology
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    • v.19 no.2
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    • pp.9-16
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    • 1983
  • The effect of higenamine upon the interval-strength relationship was kinetically analyzed, and compared them with epinephrine and calcium ion. The followings are result obtained : 1) Polyphasic patterns were seen by all agents applied on the interval-force curve of rabbit atrial muscle. 2) Higenamine, unlike calcium ion, increased the amount of PIEA produced per beat dose-dependently and scarcely affected the disappearance of NIEA. 3) Higenamine appeared to similar pattern with epinephrine in augmenting the PIEA, not affecting the NIEA. 4) Calcium ion slightly influenced the PIEA, rather hastened the disappearance of NIEA. From these result the positive inotropic action of higenamine was attributed solely to increment of PIEA.

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Extrapelvic Endometriosis (골반외 자궁내막증)

  • Chang, Ki-Hong;Yeon, Hye-Jeong;Park, Kyoung-Soo;Lee, Yoon-Ho;Hwang, Dong-Hun
    • Clinical and Experimental Reproductive Medicine
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    • v.20 no.2
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    • pp.177-181
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    • 1993
  • Endometriosis involving sites outside the pelvic cavity is a relatively uncommon occurrence and its frequency is cited as being less than one percent of all occurences of endometriosis. Sites previously reported in literature have described involvement of the extraperitoneal portion of the round ligament, the rectosigmoid, the appendix, and the ileum. Other more distal sites reported to have been found to have endometriosis lesions include the inguinal ligaments, the umbilicus, abdominal incisional wounds, thoracic lesions involving the pleura or diaphragm which may result in catamenial pneumothorax, the kidneys, and vulvar episiotomy wounds. Endometriosis have even been reported to occur in males. In this presentation, three cases of endometriosis, two involving the vulvar area and one involving a Pfannenstiel incision wound, is presented with a review of the pertinent literature in order to discuss its etiology, pathology, diagnosis and treatment.

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A Diagnostic Analysis on the Intensity Change of Typhoon NAKRI(0208) (태풍 나크리(0208)의 강도변화에 관한 진단적 분석)

  • Kim, Baek-Jo;Kim, Kyung-Sik;Chang, Ki-Ho;Park, Jong-Kil
    • Journal of Environmental Science International
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    • v.22 no.3
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    • pp.319-329
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    • 2013
  • In this study, the cause of rapid intensity change of typhoon Nakri(0208) in view of point of a trough-typhoon interaction using diagnostic methods was examined based on 6-hourly GDAPS data from 10 to 13 July, 2002. At 0000 UTC 13 July, high PV(Potential Vorticity) region moved southeastward, reaching to the western edge of the Korean peninsula and near typhoon center at surface and there shows an increasing value of EFC(Eddy Momentum Flux Convergence). Also, as the trough and typhoon approach one another at the same time, the vertical shear(850-200 hPa) increases to more than 15 m/s. Thus, it might be concluded that the trough-typhoon interaction made intensified significantly, providing the fact that typhoon Nakri(0208) underwent substantial weakening while moving northward to around Jeju island.

Design and Implementation of a ZigBee Nework-based Integrated AFCI (지그비 네트워크 기반 복합형 AFCI 설계 및 구현)

  • Chang, Ki-Heung;Kim, Kee-Min;Kim, Jae-O;Ahn, Hyun-Sik
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.4
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    • pp.41-48
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    • 2010
  • In this paper, a new type of integrated AFCI is designed and implemented by combining individual circuit breaker characteristics, which can effectively detect arc fault signals in real-time. The proposed integrated AFCI satisfies the UL1699, the USA certification standard, and the Korean circuit breaker standards such as KS C4613 and KS C8321. Data signals are transferred to the management server via ZigBee network to analyze dangerous factors and to prevent unwanted trip. It is also shown by experiments that arc fault signals are detected and analyzed by using the integrated AFCI with ZigBee networks.

Anesthetic Management of the Dental Treatment in a Child with Liver Failure Scheduled for Liver Transplantation - A case report - (간이식 예정인 간부전 환아의 치과치료 시 마취관리 -증례 보고-)

  • Park, Chang-Joo;Jang, Ki-Taeg;Yum, Kwang-Won;Kim, Hyun-Jeong
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.2 no.2 s.3
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    • pp.114-117
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    • 2002
  • Special anesthetic considerations were required for children with acute or chronic liver disease. We experienced a case of dental treatment to control infection under general anesthesia in the 2-year-old girl with liver failure. She was also scheduled for liver tansplantation. Her preanesthetic results of liver function test, electrolytes, and coagulation panel were unstable and out of normal ranges. Uneventful anesthetic induction using isoflurane and atracurium and nasotracheal intubation were carried out. General anesthesia was maintained with isoflurane for 2 hours. Oozing from multiple extraction sites was sustained, so the transfusion of platelet concentration 1 units, fresh frozen plasma 1 unit, and packed red blood cell 1 unit was done. She was recovered without complication but was transferred to pediatric intensive care unit for wound care with her endotracheal tube kept. She was transferred to a ward without noticeable complications next day. So we report this successful case of anesthetic management for dental treatment in a child with liver failure.

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A Study on the Physical Properties and Adhesion Characteristics of Polyurethane Resin (폴리우레탄 수지의 물성 및 접착특성에 관한 연구)

  • Kim, Young-Joon;Chang, Ki-Young;Kim, Gu-Ni;Chun, Yong-Chul;Yoo, Chong-Sun;Park, Sang-Wook
    • Elastomers and Composites
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    • v.31 no.2
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    • pp.104-110
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    • 1996
  • The polyurethane was synthesized by the reaction of polycaprolactone diol(Mw 2000), 4,4'-diphenylmethane diisocyanate and 1,4-butanediol as the chain extender. Also, the modified polyurethane polymers based on liquid polybutadiene as a part of soft segment and dimethylolpropionic acid as a chain extender, giving polyurethane with various polarity, were synthesized. The thermal, mechanical, adhesion properties and water contact angles of the polyurethanes were examined. From the result of the water contact angle, the polarity of the acid modified PU containing 6% acid content was unchanged but mechanical and adhesion properties were improved. The water contact angles on polybutadiene modified PU films were increased with increasing polybutadiene content. The mechanical properties of the polybutadiene modified PU were higher than that of acid modified PU. However, the mechanical properties were reduced as polybutadiene content increased. The result is presumably due to phase separation between hard segment and soft segment. The peel strength of the polyurethane introduced with 5wt% polybutadiene was improved about 150% than that of unmodified PU. The same as the mechanical properties, the more polybutadiene was introduced, the lower peel strength was obtained.

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Effect of Electromyographic Biofeedback Training on the Muscle Activities of Unilateral Facial Palsy (근전도 바이오피드백을 이용한 훈련이 안면신경마비 환자의 운동학습에 미치는 영향)

  • Kim, Won-Ho;Park, Eun-Young;Chang, Ki-Yeon;Lee, Young-Jung
    • Physical Therapy Korea
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    • v.9 no.3
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    • pp.101-111
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    • 2002
  • The purpose of this study was to determine EMG biofeedback training effect on the muscle activities in 3 unilateral facial palsy patients along with multiple baseline design across subjects. The auditory feedback about facial muscles (orbicularis oris, orbicularis oculi, frontalis) was provided with each patient during facial exercise training. Electromyographic (EMG) activity during maximal voluntary contraction and maximal compound muscle action potential (CMAP) amplitude elected by supramaximal electrical stimulation on facial nerve of facial muscles were measured pre- and post- EMG biofeedback training to evaluate motor learning. EMG activity during maximal voluntary contraction was increased after EMG biofeedback training and CMAP amplitude elected by supramaximal electrical stimulation was not changed in all subjects. The results indicate that EMG biofeedback training is useful method to improve motor learning of facial excercise training in unilateral facial palsy patients.

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