• 천문학회보
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• 제39권2호
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• pp.98-98
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• 2014

Due to the simple vertical structure of magnetic field, pores can be exploited to study the transport of mechanical energy by waves along the magnetic field to the chromosphere and corona. For a better understanding of physics of pores, we have investigated chromospheric traveling features running across two merged pores from their centers at the speed about 55 km s-1, in the active region AR 11828. The pores were observed on 2013 August 24 by using high time, spatial, and spectral resolution data from the Fast Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope (NST). We infer a LOS velocity by applying the bisector method to the Ca II $8542{\AA}$ band and $H{\alpha}$ band, and investigate intensity and the line-of-sight velocity changes at different wavelengths and different positions at the pores. We find that they have 3 minutes oscillations, and the intensity oscillation from the line center is preceded by that from the core ($-0.3{\AA}$) of the bands. There is no phase difference between the intensity and the LOS velocity oscillations at a given wavelength. The amplitude of LOS velocity from near the core spectra is greater than that from the far core spectra. These results support the interpretation of the observed wave as a slow magnetoacoustic wave propagating along the magnetic field lines in the pores. The apparent horizontal motion and a sudden decrease of its speed beyond the pores can be explained by the projection effect caused by inclination of the magnetic field with a canopy.

• 한국전자파학회논문지
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• 제22권1호
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• pp.47-58
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• 2011

MTI 필터는 대부분의 레이더 신호 처리에서 클러터로부터 표적을 분리하는데 이용된다. CFAR 검파 전 클러터를 제거됨으로써 탐지 성능이 개선될 수 있다. 레이더 시스템을 설계할 때, 일반적으로 설계자는 평균 SNR과 CNR을 고려하고 MTI 필터의 주파수 응답에 의한 영향은 포함되지 않는다. 실제의 경우, 클러터를 포함한 신호들이 필터를 통과할 때, SNR은 표적 속도에 따라 크게 변화하고, CNR 역시 클러터 중심 속도와 스펙트럼 퍼짐에 따라 변화하게 된다. 본 논문에서는 MTI 필터의 주파수 응답과 표적의 속도와 클러터의 스펙트럼 특성 간의관계를 유도하였다. 필터 출력의 SNR과 CNR의 변화에 의한 CFAR 탐지 성능을 시뮬레이션을 통해 분석하였고, 성능에 미치는 영향을 확인하였다.

• 대한기계학회논문집
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• 제12권4호
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• pp.847-864
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• 1988

본 연구에서는 연료분출에 박리가 있는 경우와 없는 경우 각각에 대하여 화염 대 근처의 국부가속 현상이 박리에 의하여 어떻게 영향을 받는가를 실험적으로 규명하 고, 나아가서 종래에 행해져 왔던 관련 연구 결과를 재검토할려고 한다.

• Archives of Reconstructive Microsurgery
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• 제19권1호
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• pp.56-60
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• 2010

Purpose: Breast reconstruction with abdominal flap has many advantages. However, it might cause abdominal complications such as bulging or hernia. SIEA (Superficial inferior epigastric artery) flap is the most advanced form of abdominal flap which has no adverse effect on abdominal fascia. We report 2 cases of breast reconstruction with SIEA flap with reference review. Methods: From Jun 2006 to Jan 2009, 110 patients underwent breast reconstruction with free abdominal flap. We tried to find the SIEA in every cases and adopted SIEP flap if the diameter was larger than 1mm and it had visible pulsation. 2 patients underwent breast reconstruction with SIEA flap. After design of abdominal flap SIEA was investigated with portable Doppler. SIEA was usually found 4-5 cm lateral to the midline. Flap was elevated with SIEA and SIEV to their maximal length at hiatus. Results: There were no complications, such as infection, hematoma, and necrosis of flap. In both cases, flaps survived completely with excellent vascularity and breast reconstruction was successful. In one case, there was skin necrosis of mastectomy flap, and it was healed by conservative management. Conclusion: With the SIEA flap, donor site morbidity can be minimized along with reduction of operation time. If there is reliable SIEA, SIEA flap would be the preferred skills. However, the limitation of the SIEA flap is difficulty in identifying the SIEA. The reason for less availability of the flap in Korea might include high prevalence of the Caesarian section scar and relatively higher level of the lower margin of the flap.

• 대한본초학회지
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• 제23권4호
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• pp.71-79
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• 2008

Objectives: SimJeok-Hwan(CP, Cardiotonic Pills) was made to treat patients with coronary arteriosclerosis, angina pectoris and hyperlipidemia. This study was designed to investigate the effects of CP on Proliferation rates neuroglia cells and protective effect of CP against oxidative stress, and also investigate the effects on regional Cerebral Blood Flow(rCBF) in normal rats. Methods: In this experiment, effects of CP on proliferation rates of neuroglia cells were measured using modified MTT methods. Oxidative stress was induced by treatment with 200 mM of hydrogen peroxide for 2 hr. rCBF and MABP were measured using Laser doppler flowmeter. Results: Treatment with CP elevated proliferation rates in C6 cells. In addition, CP protected cell death of C6 cells induced by oxidative stress. In results, rCBF was elevated by treatment with CP in normal rats. But, Mean Arterial Blood Pressure(MABP) did not affected by CP. In addition, the elevation of rCBF was blacked by pre-treatment with 1 mg/kg of indomethacin effectively. On the other hand, pre-treatment with 0.01 mg/kg of methylene blue did not affect rCBF level in normal rats. Conclusions: In conclusion, these results suggest that CP can act as anti-oxidant to protect neuroglia cells and also suggest that CP can elevate rCBF, which are involved in cyclooxygenase pathway.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.821-832
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• 2011

Recently, the noise of vehicle is the one of the key factors for customers to purchase a vehicle and the most important part which is related to the noise is the exhaust system. Thus, car makers have their own ways to assess this exhaust noise not only to decrease the level of noise but to enhance the feeling of it. Typically, to do these things in the early stage of development, the tuning code of the exhaust system has to be made by CAE tool, which is very reliable but expensive, and the prototype parts of this code would be made for the validation test. Then this process can be iterated to meet the target of the performance. In this study, a new algorithm which adapts the '3 dimensional convective sound wave theory 'and 'Doppler effect' has been developed. With this new algorithm, a brand new system for the calculation of tail pipe noise has been developed and validated by acoustic wind tunnel test. As a result of this study, various comparisons and have been carried out, for example, the comparison with other CAE tool has been performed for the validity and the improvement of the new calculation code could be achieved.

• 동의생리병리학회지
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• 제17권2호
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• pp.416-422
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• 2003

Jaeumgenby-tang(JGT) have been used in oriental medicine for many centuries as a therapeutic agent of vertigo caused by deficiency of qi(氣) and blood(血). Effect of Aurantii Fructus(AF) take off the phlegm by promoting the circulation of qi, Gastrodae Rhizoma(GR) has effects treating for headache, vertigo by calming the liver and suppressing hyperactivity of the liver-yang(陽). And, We reported that JGT adding AFㆍGR extract(JGTAG) was significantly increased regional cerebral blood f1ow(rCBF) by dilating pial arterial diameter(PAD). Therefor we designed to investigate whether JGTAG is mediated by adrenergic β-receptor, cyclooxygenase or guanylate cyclase in normal rats. The changes of rCBF and mean arterial blood pressure(MABP) were determinated by laser-doppler flowmetry(LDF), and the change of PAD was determinated by video microscope and width analyzer. The results were as follows in normal rats; Pretreatment with propranolol(1mg/kg, i.v.) was significantly inhibited JGTAG induced increase of rCBF, PAD and MABP, and pretreatment with indomethacin(1 mg/kg, i.v.) was significantly inhibited too. But pretreatment with methylene blue(10μg/kg, i.v.) were accelerated JGTAG induced increase of rCBF and MABP, but pretreatment with methylene blue was inhibited JGTAG induced increase of PAD. This results suggest that the mechanism of JGTAG is mediated by adrenergic β-receptor and cyclooxygenase.

• 한국통신학회논문지
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• 제35권6C호
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• pp.530-538
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• 2010

본 논문에서는 선형 등간격 어레이를 갖는 이동 릴레이를 위한 셀 탐색 및 입사각 추정 기법을 제안한다. 제안된 기법은 이동 릴레이에 수신되는 각 기지국 신호간에 심볼 타이밍 옵셋이 존재하는 경우에 심볼 타이밍 옵셋의 영향을 제거하여 셀 탐색 및 입사각 추정 성능을 향상시킨다. 또한 제안된 기법은 이동 릴레이가 이동함에 따라 발생하는 도플러 주파수 천이가 존재하는 경우에 입사각 추정 성능을 크게 향상시킬 수 있다. Mobile WiMAX 환경 하에서 제안된 기법의 셀 탐색 및 입사각 추정 성능과 복잡도를 모의실험을 통해 검증한다.

• The Journal of the Acoustical Society of Korea
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• 제14권2E호
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• pp.57-64
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• 1995

본 연구에서는 천해환경에서 저주파 음향신호의 신경회로망에 기초한 식별시스템 적용 가능성을 살펴 본다. 220 Hz 주파수에서 도플러 변이와 주파수 확산 효과를 추정한 결과 시간에 따라서 2 Hz 이하의 변화를 보인다. 이러한 주파수의 작은 변화는 신경회로망에 기초한 식별시스템이 단지 토널 주파수 정보만으로도 신호의 식별을 가능하게 한다. 신경회로망은 모두 4개의 층으로 이뤄져 있으며, 입력과 출력 처리요소는 각각 60개와 4개로 구성되어 있다. 주파수 200-250 Hz 대역에서 실측한 토널 신호를 신경회로망에 기초한 식별시스템에 입력시킨 결과 순간적인 프레임의 경우에 대해서는 67% 이상, 그리고 연속되는 5개의 프레임을 평균한 경우에 대해서는 91% 이상의 신호를 식별할 수 있다.

• 한국전문물리치료학회지
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• 제9권2호
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• pp.107-113
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• 2002

This study was conducted to determine the effects of deep breathing exercise and ankle exercise on blood flow velocity in the femoral vein. Sixteen healthy male students were recruited from Yonsei University, at Wonju. The blood flow velocities in the femoral vein were measured under three different conditions: resting, deep breathing, and ankle exercise. All subjects were given a 5-minute relaxing time in supine position prior to the study. Using a doppler ultrasound with a 8 MHz probe, the peak blood flow velocities were collected in a twenty-second-period at each condition. The subjects took a rest in between trials for the blood flow to return to its resting levels. The result showed a significant difference in peak blood flow velocities under those three conditions (p<.001). The peak blood flow velocity was highest in ankle exercise condition. The peak blood velocity was significantly higher in deep breathing condition compared with the resting condition. As a result, it is revealed that not only the muscular contractions but also the deep breathing exercises induced facilitating effects of venous return. Either of the exercise methods can be recommended to prevent blood stasis in patients with risk of deep vein thrombosis after cardiac or lower extremity surgery.