• Journal of the Optical Society of Korea
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• 제11권3호
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• pp.118-123
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• 2007

The emitting structure of multi-channel-type flat fluorescent lamps (FFLs) combined by a lenticular-lens-patterned diffuser plate was optimized by the ray tracing technique. The optimal parameters such as the distance between the channels of the FFL and the distance between the FFL and the diffuser plate were suggested from the viewpoint of the luminance uniformity. The best luminance uniformity, which was higher than 90%, was obtained at the channel distance of 4 mm and the distance of 12.5 mm between the FFL and the patterned diffuser plate.

• 한국융합학회논문지
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• 제11권2호
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• pp.167-174
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• 2020

사회적, 문화적 배경이 유사한 한국과 일본에서 선호하는 유튜브 콘텐츠의 특징과 성향에 대한 기초 데이터를 제공하며, 인기 콘텐츠 제작을 위한 힌트를 얻고자 양국의 인기 상위 250개의 유튜브 채널 콘텐츠를 조사, 분류하고 사회통계학적 접근 방법을 활용하여 유튜브 채널 운영 주체의 유형, 콘텐츠 채널의 분야별 분포, 한일 양국의 개인 유튜브 가입경과일과의 연관성에 대해 알아보았다. 그 결과, 한국은 방송사와 연예 기획사 등이 K-pop, 드라마, 예능 등의 한류 콘텐츠의 확산을 위한 글로벌 마케팅을 목적으로 한 홍보 영상을 제작, 채널 개설, 운영하는데 반해, 일본은 도구나 물건, 행동과 관련된 실험, 토크쇼, 일상 등을 소재로 하는 개인 유튜브 채널의 운영이 많고 분야별 다양성 및 독창성이 인정된다. 이는 일본 개인 크리에이터들이 이른 시기부터 니코니코동화(ニコニコ動画)와 같은 콘텐츠 운영 활동을 통해 콘텐츠의 독창성과 다양성을 기르기 위한 시간 확보가 가능했기 때문이다. 향후, 유튜브 영향력의 증대를 고려하여 개인 크리에이터들은 콘텐츠 소비자의 특성을 파악하여 감정적, 지식적, 경제적 가치에 기반한 다양한 시도를 해야 하며, 사회적으로는 1인 미디어 제작과 운영의 활성화를 위한 교육과 홍보 그리고 경제적 지원책이 필요하다.

• The Korean Journal of Physiology and Pharmacology
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• 제8권4호
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• pp.227-235
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• 2004

The aim of the present study was to examine the effect of leptin on CA release from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. Leptin $(1{\sim}100\;ng/ml)$, when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced a dose-dependently the secretory responses of CA evoked by ACh $(5.32{\times}10^{-3}\;M)$, DMPP $(10^{-4}\;M)$ and McN-A-343 $(10^{-4}\;M)$, although it alone has weak effect on CA secretion. However, it did not affect the CA secretion evoked by excess $K^+\;(5.6{\times}10^{-2}\;M)$. Leptin alone produced a weak secretory response of the CA. Moreover, leptin (10 ng/ml) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$ ATPase. However, in the presence of U0126 $(1\;{\mu}M)$, an inhibitor of mitogen-activated protein kinase (MAPK), leptin no longer enhanced the CA secretion evoked by ACh and DMPP. Furthermore, in the presence of anti-leptin (10 ng/ml), an antagonist of Ob receptor, leptin (10 ng/ml) also no longer potentiated the CA secretory responses evoked by DMPP and Bay-K-8644. Collectively, these experimental results suggest that leptin enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors), but does not that by membrane depolarization. It seems that this enhanced effect of leptin may be mediated by activation of U0126-sensitive MAPK through the leptin receptors, which is probably relevant to the activation of the dihydropyridine L-type $Ca^{2+}$ channels located on the rat adrenomedullary chromaffin cells.

• ETRI Journal
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• 제36권1호
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• pp.42-50
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• 2014

Orthogonal frequency division multiplexing (OFDM) is a modulation technique that allows the transmission of high data rates over wideband radio channels subject to frequency selective fading by dividing the data into several narrowband and flat fading channels. OFDM has high spectral efficiency and channel robustness. However, a major drawback of OFDM is that the peak-to-average power ratio (PAPR) of the transmitted signals is high, which causes nonlinear distortion in the received data and reduces the efficiency of the high power amplifier in the transmitter. The most straightforward method to solve this problem is to use a nonlinear mapping algorithm to transform the signal into a new signal that has a smaller PAPR. One of the latest nonlinear methods proposed to reduce the PAPR is the $L_2$-by-3 algorithm, which is based on the discrete sliding norm transform. In this paper, a new algorithm based on the $L_2$-by-3 method is proposed. The proposed method is very simple and has a low complexity analysis. Simulation results show that the proposed method performs better, has better power spectral density, and is less sensitive to the modulation type and number of subcarriers than $L_2$-by-3.

• 전기전자학회논문지
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• 제7권1호
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• pp.16-21
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• 2003

유효 유전체 해석법에 기초한 정확한 모드 전송선로 이론이 세 채널 rib형 광 방향성 결합기의 편파된 빔 분리를 분석하기 위하여 소개되고 발전되었다. 또한, 본 논문에서 제안한 방법의 타당성을 보이기 위하여 상용 소프트웨어인 BeamPROP를 이용하여 그 결과들을 비교 검토하였다. 분석결과, 하나의 채널을 통하여 rib형 광 방향성 결합기에 입사된 혼성(hybrid) 모드들은 임의의 편파거리를 진행한 후에 상, 하 채널을 통하여 잘 분리됨을 알 수 있었다.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.36-36
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• 2002

In the present study, we investigated effects of extracellular zinc (Zn$\^$2＋/) on T-type Ca$\^$2＋/ channel isoforms (${\alpha}$lG, ${\alpha}$lH, and ${\alpha}$lI) stably expressed in HEK 293 cells. Ca$\^$2＋/ currents were measured using 10 mM Ca$\^$2＋/ as a charge carrier under whole cell-ruptured patch configuration. Zn$\^$2＋/ blocked the ${\alpha}$lH currents with a 100- and 200-fold higher potency (IC$\sub$50/ = 2.5 ${\mu}$M) when compared with those for blockade of the ${\alpha}$1G and ${\alpha}$1I currents, respectively.(omitted)

• 대한족부족관절학회지
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• 제3권1호
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• pp.40-48
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• 1999

The neck of the talus is its most vulnerable and fragile segment, because of narrow diameter, devoid of hyaline padding and honeycombed internally by vascular channels etc. Talar neck fractures comprise 50% of all major to the talus. The majority occurs as a result of high-energy injuries, such as motor vehicle accidents or fall from a height. Anatomically, talar surface is covered mainly with articular cartilage and blood supply to the talus is very poor. So, complications, such as non-union, avascular necrosis and post traumatic arthritis, are frequent. The authors reviewed fourteen cases of talar neck fractures treated in our clinics from Jan. 1992 to Mar. 1997, and average follow-up period was over 15 months. The results obtained were as follows; 1. Patients' average age was 31.2 years. 2. The most common cause was traffic accident(9/14, 64%), and hyperdorsiflexion injury of the ankle was common mechanism of the fractures. 3. According to the modified Hawkins classification, type I was four cases, type II was nine cases, type III was one case and type IV was no case. 4. Hawkins sign of subcortical radiolucency was found in 64% (9/14) of the fractures. 5. Avascular necrosis was occurred in 21% (3/14) of the fractures(in two cases of type II fractures, and in one of type III). 6. According to the Hawkins criteria, four cases in type I, five in type II were an excellent result. Two cases, one in type II and one in type III were good result, and two in type II were fair. One in type II was poor result.

• The Korean Journal of Physiology and Pharmacology
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• 제11권3호
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• pp.97-106
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• 2007

The present study was attempted to investigate the effect of nicorandil, which is an ATP-sensitive potassium ($K_{ATP}$) channel opener, on secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane depolarization from the isolated perfused rat adrenal glands. The perfusion of nicorandil ($0.3{\sim}3.0mM$) into an adrenal vein for 90 min produced relatively dose-and time-dependent inhibition in CA secretion evoked by ACh (5.32 mM), high $k^+$ (a direct membrane depolarizer, 56 mM), DMPP (a selective neuronal nicotinic receptor agonist, $100{\mu}M$ for 2 min), McN-A-343 (a selective muscarinic $M_1$ receptor agonist, $100{\mu}M$ for 4 min), Bay-K-8644 (an activator of L-type dihydropyridine $Ca^{2+}$ channels, $10{\mu}M$ for 4 min) and cyclopiazonic acid (an activator of cytoplasmic $Ca^{2+}$-ATPase, $10{\mu}M$ for 4 min). In adrenal glands simultaneously preloaded with nicorandil (1.0 mM) and glibenclamide (a nonspecific $K_{ATP}$-channel blocker, 1.0 mM), the CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were recovered to the considerable extent of the control release in comparison with that of nicorandil-treatment only. Taken together, the present study demonstrates that nicorandil inhibits the adrenal CA secretion in response to stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization from the isolated perfused rat adrenal glands. It seems that this inhibitory effect of nicorandil may be mediated by inhibiting both $Ca^{2+}$ influx and the $Ca^{2+}$ release from intracellular store through activation of $K_{ATP}$ channels in the rat adrenomedullary chromaffin cells. These results suggest that nicorandil-sensitive $K_{ATP}$ channels may play an inhibitory role in the regulation of the rat adrenomedullary CA secretion.

• 대한임상독성학회지
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• 제4권2호
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• pp.166-169
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• 2006

Poisonings caused by 'mad honey' are known to occur in response to grayanotoxins, which bind to sodium channels in the cell membrane, increasing membrane sodium permeability and preventing inactivation. Mild symptoms of mad honey intoxication are dizziness, weakness, hypersalivation, nausea, vomiting, and paresthesia. Severe intoxication, however, leads to serious cardiac manifestations such as atrioventricular block, dose-dependent hypotension, bradycardia, and respiratory depression. Atropine and vasoactive drugs improve symptoms of both bradycardia and respiratory rate depression. We report an unusual case of saliva-type hyperamylasemia in a mad honey poisoning patient who developed clinically significant bradycardia. She recovered fully within 3 days following atropine administration and medical treatment.

• 대한기계학회논문집B
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• 제39권12호
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• pp.953-963
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• 2015

산업적으로 얇은 사각유로에서의 임계열유속을 포함한 열수력 현상을 이해하고 이를 시스템 설계에 반영해야 될 필요성이 증대되고 있다. 포화비등조건에서 임계열유속이 발생하는 주요기구는 일반적으로 환상유동 영역에서 액막이 건조되는 것이다. 이러한 임계열유속을 예측하기 위하여 원형관에 대한 대표적인 액막건조모델을 고찰하고 환상유동 시작 경계조건을 상수로 가정하는 기존 모델의 한계를 살펴보았다. 균일한 열유속으로 가열되는 얇은 수직사각유로 상향유동에서의 임계열유속을 예측하기 위하여 환상유동을 단순 모델링하고, 새로운 액막건조모델을 적용하였다. 284 개 실험데이타에 대한 예측성능을 확인한 결과 MAE 18.1%, RMSE 22.9% 예측오차로 실험데이타를 잘 예측할 수 있음을 확인하였다.