• Korean Journal of Acupuncture
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• v.27 no.1
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• pp.13-22
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• 2010

Objectives: The information on the depth where pulse wave appears is as important as pulse waveform. The aim of this study was to classify pulse pattern using pressure-height(P-H) volume-curve by 5 applied pressure levels to find out the information on the depth of pulse and interpret the floating & sinking pulse in oriental medical pulse diagnosis. Methods: We used 3 dimensional pulse imaging analyser (DMP-3000, DAEYOMEDI Co., Korea), which measures radial pulse waveforms noninvasively by way of tonometric method at 5 applied pressure levels, and shows P-H volume-curves by applied pressure. 448 subjects were enrolled, pulse waveforms were measured and the P-H volume-curves were gained on the three locations of Chon, Kwan, and Cheok. Results: Gained P-H volume curves were classified into 3 types ; increase type, decrease type, and increase-decrease type. Increase-decrease type appeared more often on Chon and Kwan, while increase type appeared more often on Cheok. In a few cases, decrease-type appeared on Chon and Kawn, however it never appeared on Cheok. Conclusions: Through the classification of pulse by P-H volume-curve, we gained the information on the depth of pulse. We speculate the decrease type as floating pulse, the increase-decrease type as middle pulse, and the increase type as sinking pulse in oriental medical pulse diagnosis. After more researches on P-H volume-curve by applied pressure, the P-H volume-curve may be used as an important factor for pulse diagnosis.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.3
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• pp.92-99
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• 1996

The effects of membrane fouling on the water permeability were examined using the hollow fiber microfiltration (HMF)membrane. A membrane module with a pore size of 0.1 micron was submerged in the permeation tank and water bath. The applied pressure was 12.4 kPa for direct solid-liquid separation of activated sludge. As the concentration of MLSS(880~2180mg/l) of the feed solution increased, the decreasing rates of the water flux increased and the membrane was clogged more rapidly. The water flux through the membrane did not increase effectively even with the increase in the applied pressure(40.0~93.3kPa). When the membrane was cleaned with water, the recovery rate of water flux were larger for lower applied pressure. The results indicated that the process of direct solid-liquid separation using HMF membrane was effective at lower pressure.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.232-233
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• 2002

Nanostructed high energy Nd-Fe-B based bulk magnet can be prepared by hot-working process (hot press and die-upset) from melt-spun amorphous or nanocrystalline powder.[1] Recently, we have investigated a modified method, current-applied pressure-assisted (CAPA) process, to produce nanocrystalline isotropic and anisotropic NdFeB magnets. The process consists of current-applied pressing the melt-spun powders to obtain isotropic precursor subsequent current-applied deforming the precursor to obtain textured magnet.[2-3] (omitted)

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.154-160
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• 2004

Hydraulic breaker of excavator has been used for the destruction and disassembling of buildings, crashing road pavement, breaking rocks at quaky and etc. The performance of breakers is evaluated their own destructive force and the number of impact by input hydraulic flow rate and pressure on the operating conditions. Because hydraulic breakers generate high impact energy, the accurate measurement of the impact force has been facing a technical challenge. In this study, the hydraulic pressure transducer system was developed based on the characteristics of pressure variation in closed vessel fur testing the impact energy. The hydraulic pressure transducer system is consisted with a hydraulic cylinder, main base, pressure & temperature sensors, LVDT, data acquisition system and etc. The developed hydraulic pressure transducer system was applied to measure the impact energy for hydraulic breaker. The measured impact force was 438.8 kgf.m within the designed impact force bounds. The developed hydraulic pressure transducer system as a simple tester could be applied to measure the impact force and the number of impact.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.272-280
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• 2003

A definite shut-in pressure in hydraulic fracturing techniques is needed for obtaining the correct information on the in-situ stress regimes in rock masses. The relation between the behaviour of hydraulically induced fractures and the condition of remote stress is considered to be major reasons of an ambiguous shut-in pressure in hydraulic fracturing pressure-time history curves. This paper describes the results of a series of numerical analyses carried out using UDEC(Universal Distinct Element Code, Itasca), which is based on the discrete element method, to compare several methods for determining the shut-in pressure during hydraulic fracturing. The fully coupling of hydraulic and mechanical analysis was applied, and the effects of four different discontinuity geometries in numerical modelling have been investigated for this purpose. The effects of different remote stress regimes and different physical properties on hydraulic fracture propagation have been also analyzed. Several methods for obtaining shut-in pressure from the ambiguous shut-in curves have been applied to all the numerical models. The graphical intersection methods, such as (P vs. t) method, (P vs. log(t)) method, (log(P) vs. log(t)) method, give smaller values of the shut-in pressure than the statistical method, (dP/dt vs. P). Care should be taken in selecting a method for shut-in pressure, because there can be existed a stress anomaly around the wellbore and fracturing from the wellbore by a constant flow rate may have a more complicate mechanism.

• Journal of Power System Engineering
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• v.9 no.3
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• pp.71-78
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• 2005

A high-pressure hose includes rebar layers of the synthetic fiber such as nylon or a steel wire to control internal pressure. The hose assembly is manufactured through the swaging process to clamp the hose into the metal fittings. Usually, the hose behavior is affected by the resultant of the longitudinal and circumferential forces produced by the internal pressure. The rebar layers can appear the most ideal rebar effect when they are arranged to the same direction as the resultant force. The braid angle applied in the rebar layers is an important factor in determining ultimate burst pressure and overall hose life. Failure can occur on the contacted parts of a hose with the metal fittings under severe operating conditions such as high pressure and temperature of the inner fluid. In this paper, the mechanical behavior between the hose and the metal fittings during the swaging process and the stress variation characteristics of a high-pressure hose under a constant applied pressure are analyzed with respect to the braid angle of steel wire using the finite element method.

• Journal of Information Display
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• v.10 no.1
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• pp.45-48
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• 2009

The ionization of a helium atom was investigated as a function of gas pressure, with the use of a tungsten tip. The tungsten tip, to which the external voltage was applied, was used to generate a constant electron current. The ionization current of helium gas was measured as a function of gas pressure. Effective ionization occurred in the pressure range of 0.5-20 torr when the distance between the field emission tip and the collector was 1 cm. The ionization current was linearly proportional to the voltage that was applied to the tungsten tip.

• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.235-242
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• 2016

A system for measuring the electrodermal activity (EDA) signal occurring at the sweat glands in the left palm and left finger of the human body was implemented in this study. The EDA measurement system (EDAMS) consisted of an algometer, a biopotential measurement system (BPMS), and a PC. Two experiments were performed to evaluate the function and clinical applicability of EDAMS. First, an experiment was carried out on the linearity of the voltage and the pressure that comprised the output signals of the algometer used for applying a pressure stimulus. Second, the amplitude of the EDA signal acquired from the electrode attached to the left palm or finger was measured while increasing the pressure stimulus of the algometer. When the pressure stimulus of the algometer applied to the left scapula was increased, the amplitude of the EDA signal increased. The amplitude of the EDA signal at the left palm was observed to be greater than that at the left finger. The amplitude of the EDA signal was observed to increase in a relatively linear relation with the intensity of the pressure stimuli. In addition, the latency of the EDA signal acquired from the electrode attached to the left palm or finger was measured while increasing the pressure stimulus of the algometer. When the pressure stimulus of the algometer applied to the left scapula was increased, the latency of the EDA signal decreased. The latency of the EDA signal at the palm was observed to be less than that at the finger. The latency of the EDA signal was observed to decrease nonlinearly with the pressure stimuli.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.299-312
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• 2015

Purpose: This paper analyzes the phenomenon on the degradation of the electrical performance by the pressure in the manufacturing process of sandwich type radomes. Methods: This paper consists of two steps to analyze the relation between the electrical performance and the pressure. First, the thickness of the core of the flat panels which were fabricated with different pressure was measured with the microscope, and then the electrical performance of the flat panels was analyzed with simulation and experiment. Based on the results of the electrical performance and the measured thickness with respect to the flat panels, the relation between the electrical performance and the applied pressure in the manufacturing process was analyzed. Results: The simulated and measured results with respect to the flat panel shows that the high pressure results in the nonuniform thickness of the core, which is applied to the radome fabrication. As a result, the degradation of the electrical performance occurs because the unintended scattered field is generated as the electromagnetic wave transmits (or impinges upon) the radome. Furthermore, we observed that the electrical performance of both the flat panel and the radome got worse as the high pressure was applied. Conclusion: Through simulation and experiment, therefore, it is demonstrated that for the high pressure in the manufacturing process the nonuniform thickness of the core increases and results in the degradation of the electrical performance of the radome.

• Journal of Korea Water Resources Association
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• v.46 no.11
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• pp.1103-1113
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• 2013

In this study, determination methods of the pressure monitoring location in water distribution system were introduced and applied to sample pipe network. The best determination method of the pressure monitoring location was suggested and applied to the real city pipe network. Three kinds of determination methods of pressure monitoring locations are categorized such as the sensitivity analysis according to changing roughness coefficient, pressure contribution analysis, and sensitivity analysis according to changing demand. Further-more, pressure contribution analysis and sensitivity analysis from the results of unsteady analysis were conducted and compared each other. From the results, the most accurate and simplest method was selected in this study. Therefore, the best method can be applied for the pressure management or leakage detection as a determination method of pressure monitoring location in water distribution system.