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

• Transactions of Materials Processing
• /
• v.11 no.3
• /
• pp.246-254
• /
• 2002

A simple method to derive an optimal pressure curve, characterized by initial pressure, final pressure and pressure path, has been proposed. The initial pressure has been determined from the condition to prevent recoiling phenomenon in the early stage, while the final pressure is from the FE analysis and pressure path is from the punch penetration volume. In order to realize the pressure curve, an open loop control system based on a proportional relief valve has been developed for the renovated CNC hydroforming press. Through the comparison of experiment and analysis, the predicted pressure curve has been verified optimal curve since no defect has been observed.

• Journal of the Korean GEO-environmental Society
• /
• v.11 no.5
• /
• pp.53-60
• /
• 2010

The comprehensive tests on unsaturated weathered granite soils are carried out to obtain the soil-water characteristic curve that is the one of the essential requisites to study the unsaturated soil. The weathered granite soils were obtained at Palgong mountain in Daegu. The existing test results have been carried out without overburden pressures and volume changes. In this study, the volumetric pressure plate extractor is improved to consider two factors such as overburden pressure and volume change. The applied overburden pressures were 0, 25, 50, 75, 100kPa and volume changes were measured at each phase. he results of this study are summarized as follows: As the overburden pressure increases, the volumetric water content decreases at the same matric suction and the air entry value increases and gradient of curve at the transition zone and the size of the hysteresis loops decreases. As the overburden pressure increases, the degree of saturation increases at the same matric suction and degree of saturation of the wetting curve is higher than that of dry curve. The SWCC with volume changes are slightly larger than those without volume changes. The general equation proposed by Fredlund & Xing(1994) to fit the experimental result of the SWCC indicates good agreement. The empirical parameters a, n, m as overburden pressure show similar inclination as the existing results.

• The Korean Journal of Physiology
• /
• v.17 no.1
• /
• pp.23-28
• /
• 1983

In order to clarify the effect of steroid on the pulmonary pressure-volume curve in the pneumonectomized rabbit, the right side pneumonectomy was performed under general anesthesia with pentobarbital sodium and the remaining lung was excised on the fifth day after surgery. The intrapulmonic pressure in the excised left lung was measured at 20, 25, and 30 ml lung volume during inflation and deflation period. In the steroid treated group, the intrapulmonic pressure at 20, 25, and 30 ml lung volume during inflation was significantly decreased compared with intrapulmonic pressure of the control group. But in the pneumonectomy group the decreasing tendency of the pressure was observed. During deflation, the intrapulmonic pressure at 25 ml and 20 ml was not significantly different from the control group in pneumonectomy and steroid treated pneumonectomy group. And the lung weight was measured in each experimental group and also the lung weightbody weight ratio(L/B) was calculated. The lung weight was significantly increased in both pneumonectomy and steroid treated pneumonectomy group. Calculated L/B was increased significantly in both group. Above results suggest that steroid increases the secretion of pulmonary surfactant or affects the catabolic effect on protein metabolism of connective tissue in lung parenchyma.

• Journal of the korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.89-96
• /
• 1989

Engine analyzer is developed with the aids of personal computer, A/D converter, interfacing signal transducer and data processing computer programs. The objective of this development are that it should firstly be produced at the resonable low price compared with imported one taking advantage of using existing personal computer and printer, and it should also give good quality of performance. For the attainment of this objective, A/D converter should have been developed to meet the price limit of the equipment. The experiment is performed in a 4 cycle 4 cylinder gasoline engine by this analyzer, and all the information which are necessary for the combustion analysis can be obtained through the processing of the pressure data that are stored in the computer. These are pressure-volume curve, pressure-crank angle curve, the rate of pressure rise and heat release versus crank angle curve etc. With this developed experimental system of resonable price, it will be considered that more easy way of engine data pick-up and processing is possible.

• Journal of the Korean Society for Railway
• /
• v.8 no.1
• /
• pp.57-62
• /
• 2005

The frost heaving pressure can be a problem for weakening of the railway roadbed material. This study was initiated to investigate the soils frost heaving pressure and physical characteristics(Liquid limit, permeability, SEM analysis) resulting from freezing and freezing-thawing cycle process. Therefore, upon freezing a saturated soil in a closed-system from the top, a considerable pressure was developed. Weathered granite soils, sandy soil were used in the laboratory freezing test which sometimes subjected to thermal gradients under closed-systems. The frost heaving pressure arising within the soil samples and the temperature of the samples inside were monitored with elapsed time. The degree of saturation versus heaving pressure curve is also presented for weathered granite soil and the maximum pressure is closely related to this curve. Based on the laboratory test results, fine-grained soils with strong attractive forces between soil grains md water molecules, and additional water is attracted into the pores leading to further volume changes and ice segregation.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.8
• /
• pp.2431-2435
• /
• 1996

In order to determine the effects of hydrostatic pressure on the mechanical behavior of graphite fiber reinforced composites, the modulus, fracture stress(maximum stress), and fracture strain of graphite/epoxy composites have been determined as a function of pressure. Composite specimens used in this study were 90-deg unidirectional and had a 60% fiber volume fraction. Compressive tests under five different pressure levels were conducted. The result showed the modulus measured from as initial slope of stress-strain curve increased bilinearly with pressure with a break at 200 MPa. It was also found that fracture stress and fracture strain increased in a linear fashion with pressure.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.1
• /
• pp.55-58
• /
• 1999

Plant water status during growth is directly and indirectly associated with seed yield. The objective of the present study was to determine the genotypic differences in leaf water characteristics at an early growth stage of soybean [Glycine max (L.) Merrill] plants through the pressure-bomb technique. Measurements of water potential as well as relative water content (RWC) were made at the third leaf from the fully-expanded top leaf of eight different soybean genotypes grown for 31 to 35 days after field emergence. On the basis of the modified exponential model, pressure-volume (PV) curves were fitted well ($R^2$=0.92＊＊ to 0.99＊＊ for the curvi-linear region and R=0.67＊＊ to 0.96＊＊ for the linear region), indicating that a segmented model using PROC NLIN of SAS could be used effectively to estimate the leaf water characteristics. The regression analysis for the pressure-volume (PV) curve revealed genotypic variation in the solute potential at saturation (Ψ$_{s,sat}$ :-10.7 to -14.8 bar), solute potential at incipient plasmolysis (Ψ$_{s,ip}$ : -14.3 to -18.3 bar), RWC at incipient plasmolysis (RW $C_{ip}$ : 83.3 to 91.7%), high integrated turgor pressure from saturation to plasmolysis ( $_1$$^{b}$ : 0.39 to 0.81), and maximum volumetric modulus of elasticity ($\varepsilon$$_{max}$ : 150 to 445 bar).).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.4C
• /
• pp.185-191
• /
• 2010

Volumetric pressure plate extractor (VPPE) can be used for measurement of the soil-water characteristic curve in the laboratory using the axis-translation technique. The volume of extracted water from the soil specimen in VPPE can be measured continuously during the test without stoppage of air pressure for the measurements. However, the water volume measurement in VPPE using an air trap, a ballast tube, a burette, and a vacuum device so as to maintain a constant pore-water pressure in the soil specimen, is quite complicated and tedious. In order to improve the measuring problems of VPPE, a modified volumetric pressure plate extractor (MVPPE) was developed and tested on residual soil specimens. In addition, the modified apparatus can measure the volume of the extracted water using both Method A and Method B of ASTM D 6836-02 depending on the range of matric suction. Measuring principles and the improvements of MVPPE and typical results obtained from the tests are discussed in the paper.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.1
• /
• pp.26-34
• /
• 2008

This study presents an aerodynamic design and an experimental performance test of a turbo air compressor consisted of mixed-flow impeller and curved diffuser for the PEM fuel cell vehicle application. Many studies compare the efficiency, cost or noise level of high-pressure and low-pressure operation of PEM fuel cell systems. Pressure ratio 2.2:1 is considered as design target The goal of compressor design is to enlarge the flow margin of compressor from surge to choke mass flow rate to cover the operational envelope of FCV. Large-scale rig test is performed to evaluate the compressor performance and to compare the effects of compressor exit pipe volume to stall or surge characteristics. The results show that the mixed-flow compressor designed has large flow margin, and the flow margin of compressor configuration with small exit volume is larger than that with large exit volume.