• Journal of Biomedical Engineering Research
• /
• v.32 no.2
• /
• pp.109-117
• /
• 2011

Assuming that photons absorbed by a vessel do not have acute variations, DC component reflect the basal blood volume (or diameter) before blood pulsation. Vascular stiffness and reflection is influenced by changes in basal blood volume (or diameter). This paper describes analysis of the characteristic variations of vascular stiffness, according to relative variations in DC components of the PPG signal (25-75%). For quantitative analysis, we have used parameters that were proposed previously, reflection and stiffness index, and the second derivative of PPG waveform, b/a and d/a. Significantly, the vascular stiffness and reflections were increased according to increase in DC component of the PPG signal for more than about 3% of baseline values. The systolic blood pressure were increased from $113.1{\times}13.18$ to $116.2{\times}13.319$ mmHg, about 2.76% (r = 0.991, P < 0.001) and the AC component of the PPG signal were decreased from $2.073{\times}2.287$ to $1.973{\times}2.2038$ arbitrary unit, about 5.09% (r = -0.993, P < 0.001). It is separated by DC median and correlation analysis was performed for analyzing vascular characteristics according to instantaneous DC variations. There are significant differences between two correlation coefficients in separated data.

• Bulletin of the Korean Space Science Society
• /
• 2010.04a
• /
• pp.40.3-40.3
• /
• 2010

The most frequently suggested source for Pi2 pulsations in the inner magnetosphere (L < 4) is standing fast-mode waves trapped in the plasmasphere (i.e., plasmaspheric resonances). They have been considered as the source of low-latitude Pi2 pulsations. The plasmaspheric resonance model suggests that compressional fast-mode waves can be detected at all local times inside the plasmasphere provided reflection of the wave energy is efficient. Until now, however, there are no reports about compressional Pi2s observed in the dayside inner magnetosphere. That is, there is longitudinal limit of inner magnetosphere. In February 2008, THEMIS probes were near dawn and/or dusk sides, which are the transition regions between the nightside and dayside, in the inner magnetosphere (L = 2-4) when low-altitude Pi2s were identified at Bohyun (L = 1.35) station in Korea. Using the THEMIS electric field data, we examined if Pi2s are excited by longitudinally localized disturbances. We found that compressional Pi2s having high coherence with a low-latitude Pi2 pulsation occur on dawnside. However, any compressional pulsations in the Pi2 frequency band were not detected on duskside. This indicates that compressional Pi2s disappear near the duskside. Our observations are discussed with spatial plasmaspheric structure and possible Pi2 mechanisms.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.2
• /
• pp.963-969
• /
• 2015

Bicycle is one of the most popular mode of transport due to the increase of interest in the well-being and environment pollution. Before fabricating a continuously variable transmission that is applied to the actual bicycle, for reducing the problems in the early stage, the reliable simulation program has been applied and the financial problem can be solved. In this paper, in order to confirm the design factor, the stress analysis has been applied. In all models, each link and the joint portion are assumed to be a major design factors, and impact of each link and joints received stress during the operation and it is confirmed by using the CAE. Also, for the analysis region, the special code has been developed to calculate pulsation phenomenon through appropriate mathematical modeling.

• Journal of Power Electronics
• /
• v.11 no.3
• /
• pp.294-303
• /
• 2011

In this paper an effective five-phase induction motor (IM) and its drive methods are proposed. Due to the additional degrees of freedom, the five-phase IM drive presents unique characteristics for enhancing the torque producing capability of the motor. Also the five-phase motor drives possess many other advantages when compared to traditional three-phase motor drives. Some of these advantages include, reducing the amplitude and increasing the frequency of the torque pulsation, reducing the amplitude of the current without increasing the voltage per phase and increasing the reliability. In order to maximize the torque per ampere, the proposed motor has concentrated winding, the produced back electromotive force (EMF) is almost trapezoidal, and the motor is supplied with the combined sinusoidal plus the third harmonic of the currents. For demonstrating the superior performance of the proposed five-phase IM, the motors are also analyzed on the synchronously rotating reference frame. To supply trapezoidal current waveform and to exclude the effect of the $3^{rd}$ harmonic current, a new control stratagem is proposed. The proposed control method is based on direct torque control (DTC) and rotor flux oriented control (RFOC) of the five-phase IM drives. It is able to reduce the acoustical noise, the torque, the flux, the current, and the speed pulsations during the steady state. The DTC transient merits are preserved, while a better quality steady-state performance is produced in the five phase motor drive for a wide speed range. Experimental results clearly demonstrated a more dynamic steady state performance with the proposed control system.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.9
• /
• pp.1103-1108
• /
• 2012

A main steam pipe system is a branch pipe that connects a boiler with a turbine. Water hammering analysis is very important for limiting the damage caused to pipe systems by operation conditions. Water hammering created by an unsteady flow in pipeline systems can cause excessive change in pressure, vibration, and noise. The main steam pipe structure should be designed to safely maintain the pressure pulsation and several vibrations under operation environments. This study evaluated the structural integrity of a main steam pipe during suspended and normal operation by using the ASME fatigue life methodology and finite element analysis. In the analysis, water hammering was used for transient analysis. The calculated alternating stress and fatigue stress were compared with the applicable limits of ASME fatigue life. All the evaluation results satisfied the requirements of the ASME fatigue life.

• The Journal of Internal Korean Medicine
• /
• v.3 no.1
• /
• pp.23-32
• /
• 1986

As a result of administration of Coptidis Rhizoma extract and Zingiberis Rhizoma extract to Rat and Rabbit, its effect to the Gastric Juice Volume, Acidity, Pepsin out put of Rat and the movement of Intestine, Pulse Rate of Rabbit was as follows; 1. In the secretion of Gastric Juice, the Juice Volume in Coptidis Rhizoma administered group in contrast to Control Group, has increased in 30mg the increasing rate 21.4%, and has decreased in 300mg the decreasing rate 113.9%. But the Juice Volume in Zingiberis Rhizoma administered group has all decreased in 12, 30, 60, 120mg, and has remarkably decreased in 60mg the decreasing rate 62.9%. 2. The Gastric Acidity in Coptidis Rhizome administered group, in contrast to Control Group, has increased in 30, and 75mg, but no significant value, and has decreased in 300mg the decreasing rate 104.7%. But the Gastric Acidity in Zingiberis Rhizoma administered group has all decreased in 12, 30, 60 120mg, and has remarkably decreased in 60mg the decreasing rate 105.6%. 3. The Pepsin out-put in Coptids Rhizoma administered group, in contrast to Control group, has increased in 30mg the increasing rate 30.3%, and has decreased in 150, 300mg, no significant value. But the Pepsin out-put in Zingiberis Rhizoma administered group has all decreased in 12, 30, 60, 120mg, and has remarkably decreased in 60mg the decreasing rate 86.4%. 4. In the movement of Intestine, the contraction Coptidis Rhizoma administered group, in contrast before the administration, has increased in 12mg, but has begun to decrease in 30mg, and has remarkably decreased in 70mg. The contraction in Zingiberis Rhizoma administered group, in contrast before the administration, has all increased in 30, 60, 120mg. 5. In Pulse Rate, the pulsation, in contrast to Control group after 60, 120 180, 240min. has decreased in Coptidis Rhizoma administered group, and has increased in Zingiberis Rhizoma administered group, but no significant value.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.13 no.2
• /
• pp.1-8
• /
• 2009

Present studies of these experiments was conducted to using water, over a range of cross-flow velocities from 42 to 136 m/s, with injection frequencies from 35.7 to 166.2 Hz. In cross-flow field, main parameters of liquid jet for secondary breakup were cross-flow drag rather than pressure pulse frequency. As oscillation of the periodic pressure, liquid jet was moved up and down. Also, a bulk of liquid jet puff was detected at upper field of liquid surface. Because of pressure pulsation frequency, an inclination of SMD for the structured layer was evanescent. Cross-sectional characteristics of SMD at downstream area were non-structured distributions. The tendency of volume flux value for various frequency of pressure pulse was same distribution. And volume flux was decreased when the frequency of pressure pulse increasing.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.84.2-84.2
• /
• 2019

We present the absolute properties of the double-lined eclipsing binary KIC 6206751 exhibiting multiperiodic pulsations. The Kepler light curve of this system was simultaneously solved with the previously published radial-velocity data. The results indicate that the binary star is a short-period semi-detached system with fundamental parameters of $M_1=1.66{\pm}0.04M_{\odot}$, $M_2=0.215{\pm}0.006M_{\odot}$, $R_1=1.53{\pm}0.02R_{\odot}$, $R_2=1.33{\pm}0.02R_{\odot}$, $L_1=5.0{\pm}0.6L_{\odot}$, and $L_2=0.96{\pm}0.09L_{\odot}$. We applied multiple frequency analyses to the eclipse-subtracted light residuals and detected the 42 frequencies below $2.5days^{-1}$. Among these, three independent frequencies of $f_2$, $f_3$, and $f_4$ can be identified as high-order ($38{\leq}n{\leq}40$) low-degree (l=2) gravity-mode oscillations, whereas the other frequencies may be orbital harmonics and combination terms. The ratios between the orbital frequency and the pulsation frequencies are $f_{orb}:f_{2-4}{\simeq}2:3$, which implies that the ${\gamma}$ Dor pulsations of the detached primary star may be excited by the tidal interaction of the secondary companion. The short orbital period, and the low mass ratio and $M_2$ demonstrate that KIC 6206751 is an R CMa-type star, which is most likely evolving into an EL CVn star. Of seven well-studied R CMa-type stars, our program target is the only eclipsing binary with a ${\gamma}$ Dor pulsating component.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.86-86
• /
• 2019

We present BV photometric observations and high-resolution spectra of AO Ser, which were obtained at the Mt. Lemmon Optical Astronomy Observatory (LOAO) and the Bohyunsan Optical Astronomy Observatory (BOAO), respectively, in 2017. The radial velocities (RVs) for both components were measured, and the effective temperature of the primary star was found to be $T_{eff,1}=8,820{\pm}62K$ by a comparison of the observed spectra and the Kurucz models. A unique set of fundamental parameters of AO Ser were derived for the first time by a simultaneous analysis of the light and RV curves. The results indicate that our program target is a semi-detached eclipsing system with values of $M_1=2.06{\pm}0.11M_{\odot}$ and $M_2=0.41{\pm}0.03M_{\odot}$, $R_1=1.54{\pm}0.03R_{\odot}$ and $R_2=1.30{\pm}0.02R_{\odot}$, and $L_1=12.9{\pm}0.2L_{\odot}$ and $L_2=0.9{\pm}0.3L_{\odot}$. We applied multiple frequency analyses to the eclipse-subtracted light residuals. As a result, two frequencies of $f_1=21.85151days^{-1}$ and $f_2=23.48405days^{-1}$ were detected and their pulsation constants were calculated to $Q_1=0.0344days$ and $Q_2=0.0320days$. The pulsational characteristics and the position in the HR diagram demonstrate that the primary star is a ${\delta}$ Sct pulsator.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.34 no.4
• /
• pp.97-110
• /
• 2021

Objectives: This study was performed to review the research trends in the relationship between primary dysmenorrhea and doppler indicies of uterine artery. Methods: The search for related papers used 'Pubmed', a reserch engine in the America National Library of Medicine and Korean studies Information Service System (KISS). Used searching terms were 'primary dysmenorrhea', 'menstrual pain' in all cases. And among these studies, we searched by using key word 'uterine artery', 'doppler indices', 'doppler parameters', 'pulsatile index', 'resistance index'. Results: Overall 49 studies, 8 studies were finally selected to this study. There were 6 controlled studies and 2 randomised-controlled studies. In all 8 studies, transvaginal ultrasound was used to measure the resistance of uterine blood vessels. All of these studies reported that in patients with primary dysmenorrhea, hemodynamic values of uterine arteries measured by Doppler ultrasound were significantly higher than in normal subjects. Conclusions: According to the results, it was found that there was a positive correlation between the pain level of primary dysmenorrhea and the pulsation index and resistance index of the uterine artery. Based on these results, it can be seen that the doppler indicies of uterine artery have the potential to be used as an evaluation scale for Korean traditional medicine for primary dysmenorrhea.