• 대한조선학회논문집
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• 제44권2호
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• pp.148-153
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• 2007

Two typical impact loadings, shock wave and gas bubble pulse, due to UNDEX(UNDerwater EXplosion), should be considered together for the closest response analysis of structure subjected to UNDEX to a reality. Since these two impact loadings have different response time bands, however, their response characteristics of structure are different from each other. It is impossible to consider these effectively under the current computational environment and the mathematical model has not yet been developed. Whereas Hicks model approximates the fluid-structure interaction due to gas bubble pulse as virtual mass effect, treating the flow by the response of gas bubble after shock wave as incompressible ideal fluid contrary to the compressible flow due to shock wave, Geers-Hunter model could make the closest response analysis of structure under UNDEX to a real one as a mathematical model considering the fluid-structure interaction due to shock wave and gas bubble pulse together using acoustic wave theory and DAA(Doubly Asymptotic Approximation). In this study, the application and effectiveness of integrated dynamic response analysis of submerged structure was examined with the analysis of the shock wave and gas bubble pulse together.

• 대한약침학회지
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• 제12권1호
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• pp.35-42
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• 2009

1. Objectives To evaluate effects of bee venom acupuncture on cardiovascular system and differences according to each constitution. 2. Methods Heart rate variability, pulse wave and the velocity of cerebral blood flow were measured before bee venom acupuncture(BVA), right after and after 30 minuets, had been applied to 20 subjects. 3. Results 1. BVA did not have effects on measurement variables of heart rate variability. 2. BVA had effects on pulse wave, showing total time, radial augmentation index up and height of percussion wave, time to percussion wave, sum of pulse pressure down. 3. BVA did not have effects on the cerebral blood flow velocity when considering not Sasang Constitution. 4. Considering Sasang Constitution, BVA demonstrates different responses in time to preincisura wave, mean blood flow velocity, peak systolic velocity and end diastolic velocity. 4.Conclusion From those results, the following conclusions are obtained. Cause BVA alters pulse wave and makes differences in the cerebral blood flow velocity according to Sasang Constitution. Various methods of BVA treatment are needed considering Sasang Constitution.

• 전자공학회논문지
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• 제51권10호
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• pp.204-209
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• 2014

본 논문은 맥파전달현상을 유지하며 맥압을 조절할 수 있는 시뮬레이터를 제작하는 것이 목적이다. 이를 위해 탄성튜브와 컴플라이언스 챔버를 융합하였다. 본 시뮬레이터는 슬라이더-크랭크로 구성된 압력발생부, 저항조절부를 포함한 혈관부, 수조 그리고 측정부로 구성되어있다. 챔버의 위치선정을 위해 챔버의 위치에 따른 맥파의 변화를 실험하였다. 또한 챔버가 맥압에 미치는 영향을 보기 위해 챔버의 유무에 따른 맥압의 변화를 비교하였다. 챔버의 유무가 맥파전달현상에 미치는 영향을 조사하였다. 실험결과, 튜브의 상류지점에 챔버를 설치할 때가 하류지점에 설치할 때 보다 인체와 더 유사한 압력파형을 나타냈다. 챔버를 설치하였을 때가 설치하지 않았을 때보다 인체와 유사한 맥압을 생성하였다. 챔버의 설치여부에 따른 맥파 전달 속도는 큰 변화가 없었다.

• Advances in aircraft and spacecraft science
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• 제7권3호
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• pp.187-202
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• 2020

The exhaust nozzle serves back pressure of Pulse detonation combustor, so combustion chamber gets sufficient pressure for propulsion. In this context recent researches are focused on influence of nozzle effect on single cycle detonation wave propagation and propulsion performance of PDE. The effects of various nozzles like convergent-divergent nozzle, convergent nozzle, divergent nozzle and without nozzle at exit section of detonation tubes were computationally investigated to seek the desired propulsion performance. Further the effect of divergent nozzle length and half angle on detonation wave structure was analyzed. The simulations have been done using Ansys 14 Fluent platform. The LES turbulence model was used to simulate the combustion wave reacting flows in combustor with standard wall function. From these numerical simulations among four acquaint nozzles the highest thrust augmentation could be attained in divergent nozzle geometry and detonation wave propagation velocity eventually reaches to 1830 m/s, which is near about C-J velocity. Smaller the divergent nozzle half angle has a significant effect on faster detonation wave propagation.

• 대한한의학회지
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• 제32권4호
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• pp.139-148
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• 2011

Objective: The purpose of this study was to investigate the effect of food intake on the Fourier components of radial pulse wave. Methods: Thirty-one healthy male subjects participated in this study. Radial pulse was measured using 3 dimensional pulse imaging system (DMP-3000) before, right after, 40 minutes after, 80 minutes after and 120 minutes after food intake. Fourier transform was performed and the frequency and amplitude of Fourier components were analyzed. Results: 1. The frequency and the amplitude of Fourier components of radial pulse wave increased significantly after food intake. 2. The frequency of Fourier components increased right after food intake and then gradually decreased as time passed, however the amplitude of Fourier components increased and maintained certain levels and patterns throughout the experimental period of 120 minutes. 3. The change ratios of the frequency and the amplitude of Fourier components after food intake varied with the pulse measuring locations. Conclusions: Food intake exerts an influence on radial pulse wave, resulting in increase of frequency and amplitude of Fourier components. The change ratios of the frequency and the amplitude of Fourier components after food intake varied with the pulse measuring locations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2255-2258
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• 1998

Method of diagnosis in oriental medicine, the unbalance of the physiological function of the five viscers and six bowels of the human body is determined from time immemorial with the condition of blood circulation which is performed through blood vessels by the vitality of the heart. In oriental medicine, treatment is largely attempted by adjusting this unbalance. The analysis of pulse wave, which mainly measures the changes in blood flows, is to evaluate the shapes of a pulse wave rather than the quantitative changes like rates and strength of the pulse. This paper presents the development of Hardware System and Pulse Diagnosis Algorithm for automatic diagnosis of the pulse wave. This system makes the precise diagnosis and the objective recording possible.

• 한국광학회지
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• 제5권1호
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• pp.37-44
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• 1994

유도 브릴루앙 반사광을 고출력 레이저에 응용할 때 요구되는 반사광 특성이 실험적으로 조사되었다. 집속 렌즈의 초점거리에 따른 유도 브릴루앙 반사광의 peak power 반사율과 위상공액도가 측정되었다. 또한 반사광 가운데 펄스압축된 부분만의 위상공액도가 측정되었다. 초점거리가 긴 경우(f=100cm) 반사광의 peak power가 입사광의 약 2배에 이르렀다. 이때 반사광 중에서 압축된 선두펄스만의 위상공액도는 약 90%로 다른 시간의 펄스보다 위상공액도가 우수했다. 공간적으로는 유도 브릴루앙 이득이 가장 큰 광축부분의 바사관이 최대의 펄스압축, peak power 반사율, 위상공액도를 보여서 유도 브릴루앙 산란을 응용할 때 가장 유용한 부분으로 확인되었다.

• 설비공학논문집
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• 제13권11호
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• pp.1059-1064
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• 2001

This study Investigates the effect of the wave form of pulse energization on the collection characteristics of a wide plate spacing electrostatic precipitator. For the semi-pulse energization, the peak current and voltage of the energization increases with increase of the pulse period, and the corona current increases, as pulse ratio decreases. For the micro-pulse energization, the corona current increases with increase of the pulse voltage. The collection efficiency of semi-pulse and micro-pulse energization is larger than that of DC charge.

• Earthquakes and Structures
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• 제18권3호
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• pp.297-312
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• 2020

The KiK-net by NIED is a vertical array measurement system. In the database of KiK-net, singular pulse waves were observed in the seismic record at the borehole of TTRH02 during the mainshock (the magnitude of Japan Meteorological Agency (M_J) 7.3, M_W 6.8) and aftershock (M_j 4.2) of Tottori-ken Seibu earthquake in 2000. Singular pulse waves were also detected in the seismic records at the borehole of IWTH25 during the Iwate-Miyagi Nairiku earthquake in 2008 (M_J 7.2, M_W 6.9). These pulse waves are investigated by using the wave shape analysis methods, e.g., the non-stationary Fourier spectra and the double integrated displacement profiles. Two types of vibration modes are discriminated as the occurrence mechanism of the singular pulse waves. One corresponds to the reversal points in the displacement profile with the amplitude from 10^-4 m to 10^-1 m, which is mainly related to the fault activity and the amplification pass including the mechanical amplification (collision) of the seismograph in the casing pipe. The other is the cyclic pulse waves in the interval of reversal points, which is estimated as the backlash of the seismograph itself with the amplitude from 10^-5 m to 10^-4 m.

• 한국자기학회지
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• 제22권1호
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• pp.27-31
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• 2012

영구자석과 홀소자로 구비된 두 대의 집게형 맥진기 시제품을 이용하여 비가압 상태에서 양손 요골동맥의 맥진파형을 동시측정한 신호들을 비교 분석하였다. 20대 남성 피실험자 22명을 대상으로 측정된 오른손잡이와 왼손잡이의 두 맥진파형들은 위상차를 갖고 뚜렷하게 구별되었다. 서로 다른 빠름과 늦음으로 인해 두 개의 맥진파형들의 위상차 부호는 맥파전달속도가 오른손과 왼손 혈관의 총길이 보다는 자주 사용하는 팔의 근육 특성에 의존한다는 분석이 가능하였다.