• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.135-140
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• 2017

In this paper, a novel measurement method of radial artery pulse waveform using robotic applanation tonometry (RAT) was present to reduce the errors by the pressing direction of the vessel. The RAT consisted of an array of pressure sensors and 2-axis tilt sensor, which was attached to the universal joint with a linear spring and five-DOF robotic manipulator with a one-axis force sensor. Using the RAT mechanism, the pulse sensor could be manipulated to perpendicularly pressurize the radial artery. A pilot experimental result showed that the proposed mechanism could find the optimal pressurization angles of the pulse sensor within ${\pm}3^{\circ}$standard deviations. Coefficient values of variation of maximum pulse peaks extracted from the pulse waveforms were 4.692, 6.994, and 11.039 % for three channels with the highest magnitudes. It is expected that the proposed method can be helpful to develop more precise tonometry system measuring the pulse waveform on the radial artery.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.1
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• pp.9-16
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• 2005

To evaluate parameters influencing on the dust removal of the High Temperature Filter(HTF) system, a computer simulation of fluid dynamics inside the system had been performed. The results showed that the optimum pulse jet periods were 50ms and 90ms for the 1000mm and 1500mm long filter elements respectively. Dust removal effect was very excellent under the pulse jet pressure of 3 bar. But the distance between the pulse jet nozzle and the venturi of a filter element had no meaningful effect on the performance with the variation from 5mm to 10mm. Compared to the dispersion mode of pulse jet, the collective mode of pulse jet flow was preferable in maintaining the pressure inside the system stable.

• Journal of KSNVE
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• v.11 no.2
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• pp.285-291
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• 2001

The impingement of a weak shock wane discharged from the open end of a shock tube upon a flat plate was investigated using shock tube experiments and numerical simulations. Harten-Yee Total Variation Diminishing method was used to solve axisymmetric, unsteady, compressible flow governing equations. Experiments were carried out to validate the present computations. The effects of the flat plate and baffle plate sizes on the impinging flow field over the flat plate were investigated. Shock Mach number was varied in the range from 1.05 to 1.20. The distance between the plate and shock tube was changed to investigate the effect on the peak pressure. From both the results of experiments and computations we obtained a good empirical equation to predict the peak pressure on the flat plate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.399-404
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• 2010

Test results including the variation of propellant-inlet pressure, pulsed thrust, and environment vacuum with the accompanying thermal responses are presented for the pulse-mode operation of a set of monopropellant hydrazine thrusters producing $0.95lb_f$ of nominal steady-state thrust at an inlet pressure of 350 psia. The test data are reduced into the impulse bit, specific impulse, and force centroid that are the factors typically characterizing pulse-mode performance of small rocket engines. With a scrutiny to the performance parameters, their comparison to the reference criteria of 1 lbf standard monopropellant rocket engine are successfully made.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1817-1819
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• 2004

From the plasma application point of view, electron temperature and density are one of the most important parameters for plasma process. But it is only available to control plasma by adjusting external factors like gas pressure and input power. In this paper, pulse-modulated plasma is generated by modulating 13.56GHz RF power with 1, 5, 10kHz pulse. And Langmuir probe technique is used to study the distribution of electron temperature and density. When modulated pulse is off, electron temperature decreases gradually in form of exponential decay. The value t of exponential decay slope is 33.619, 13.834, 10.803 in 1kHz. 5kHz. 10kHz. This implies that this method can be used to control electron temperature and density.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.4
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• pp.140-149
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• 2013

Purpose: The purpose of this study is to investigate the change and correlation of pulse energy in Left and Right Chon, Kwan, Cheok during menstruation, especially around menstruation start date. Methods: The subjects of this experiment were 8 healthy women whose menstruation periods are regular. We measured 3D Blood Pressure Pulse Analyzer (3D-MAC) tests before and after menstruation start date. Results: The results were as follows 1. The pulse energy of the Right Chon was significantly decreased and Left Kwan was comparatively increased during the next day of menstruation start date than previous day. 2. There was a negative correlation between Left Kwan and Left Cheok, Right Chon and Right Kwan pulse energy during the previous and menstruation start date. The negative correlation disappeared between Right Chon and Right Kwan at the next day of menstruation start date. Conclusions: The results suggest that Chon, Kwan, Cheok pulse energy changes are related to menstruation and reflect physiological mechanism of menstruating women. Further study will be needed.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.157-164
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• 2003

The pulse-echo method is one of the most widely used ultrasonic techniques for application of nondestructive evaluation. Particularly, quantitative nondestructive evaluation of defects has been considered more important to assure the reliability and the safety of structure. Frequency energy in adhesive joints is based on the ultrasonic wave analysis. The attenuation coefficient upon wave amplitude and the frequency energy that is expressed in the term of wave pressure amplitude were utilized for the primary wave experiment. By means of a control experiment, it was confirmed that the variation of the frequency energy in adhesive joints depends on transition by stress variation. In this paper, the ultrasonic characteristics were measured for single lap joint and Double Cantilever Beam specimen with different fracture modes that was subjected to stress. Consequently, the data that was obtained from the adhesive specimen was analytically compared to the fracture mechanics parameter

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.816-824
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• 2003

In this study, variations of cutting performance with pulse time, open circuit voltage, wire speed and dielectric fluid pressure were experimentally investigated in Wire Electrical Discharge Machining (WEDM) process. Brass wire with 0.25 mm diameter and AISI 4140 steel with 10 mm thickness were used as tool and work materials in the experiments. The cutting performance outputs considered in this study were surface roughness and cutting speed. It is found experimentally that increasing pulse time, open circuit voltage, wire speed and dielectric fluid pressure increase the surface roughness and cutting speed. The variation of cutting speed and surface roughness with cutting parameters is modeled by using a regression analysis method. Then, for WEDM with multi-cutting performance outputs, an optimization work is performed using this mathematical models. In addition, the importance of the cutting parameters on the cutting performance outputs is determined by using the variance analysis (ANOVA).

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.562-567
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• 2000

The Impingement of a weak shock wave discharged from the open end of a shock tube upon a flat plate was investigated using shock tube experiments and numerical simulations. Harten-Yee Total Variation Diminishing method was used to solve axisymmetric, unsteady, compressible flow governing equations. Experiments were carried out to validate the present computations. The effects of the flat plate and baffle plate sizes on the impinging flow field over the flat plate were investigated. Shock Mach number was vaned in the range from 1.05 to 1.20. The distance between the plate and shock tube was changed to investigate the effect on the peak pressure. From both the results of experiments and computations we obtained a good empirical equation to predict the peak pressure on the flat plate.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.25-30
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• 2001

This paper studies the effect of vibration characteristics of tube line conveying fluid with the power steering system of bus. We modelled fluid-filled tube line using I-DEAS software to investigate vibration characteristics of the power steering tube line. And we obtained the natural frequency of tube line through finite element analysis. Analytic solutions were compared with experimental solutions to verify finite element model. We tested the tube line to examine an effect of pressure pulse by vane pump and variation of geometry of tube. From both the experimental results and the modeling results for vibration characteristics of the tube line conveying fluid, we confirmed that vibration characteristics induced by pulse propagated along the power steering tube line and resonance occurred around the natural frequency with pulse excitation.