• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.171-174
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• 1992

Development of a noninvasive intensive care system calls for the use of evoked potentials (EPs), as a means of diagnosing traumatic head-injured patients. The experiment entails surgically plating two subarachnoid bolts and a subdural balloon through the skull to simulate a subdural hematoma. Using various levels of intracranial pressure (ICP) and/or different sizes of balloons, auditory evoked potentials (AEPs) were recorded from a rabbit. Six positive peat latencies ($P_1-P_6$) and five negative peak latencies ($N_1-N_5$) were extracted from an averaged AEP waveform. Multiple regression analyses were performed for determining a relationship between the ICP and AEP peak latencies. The results indicate that a major correlation of changes on AEP peak latencies is due to mechanical forcer of a mass (inflated balloon simulating a hematoma) in the distortion of the brain matter rather than increased ICP.

• Physical Therapy Korea
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• v.13 no.4
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• pp.71-78
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• 2006

This study examined the effects of socket flexion angle in trans-tibial prosthesis on stump/socket interface pressure. Ten trans-tibial amputees voluntarily participated in this study. F-socket system was used to measure static and dynamic pressure in stump/socket interface. The pressure was measured at anterior area (proximal, middle, and distal) and posterior area (proximal, middle, and distal) in different socket flexion angles ($5^{\circ}$, $0^{\circ}$, and $10^{\circ}$). Paired t-test was used to compare pressure differences in conventional socket flexion angle of $5^{\circ}$ with pressures in socket flexion angles of $0^{\circ}$ and $10^{\circ}$ (${\alpha}$=.05). Mean pressure during standing in socket flexion angle of $10^{\circ}$ decreased significantly in anterior middle area (19.7%), posterior proximal area (10.4%), and posterior distal area (16.3%) compared with socket flexion angle of $5^{\circ}$. Mean pressure during stance phase in socket flexion angle of $0^{\circ}$ increased significantly in anterior proximal area (19.3%) and decreased significantly in anterior distal area (19.7%) compared with socket flexion angle of $5^{\circ}$. Mean pressure during stance phase in socket flexion angle of $10^{\circ}$ decreased significantly in anterior proximal area (19.6%) and increased significantly in anterior distal area (8.2%) compared with socket flexion angle of $5^{\circ}$. Peak pressure during gait in socket flexion angle of $0^{\circ}$ increased significantly in anterior proximal area (23.0%) compared with socket flexion angle of $5^{\circ}$ and peak pressure during gait in socket flexion angle of $10^{\circ}$ decreased significantly in anterior proximal area (22.7%) compared with socket flexion angle of $5^{\circ}$. Mean pressure over 80% of peak pressure ($MP_{80+}$) during gait in socket flexion angle of $0^{\circ}$ increased significantly in anterior proximal area (23.9%) and decreased significantly in anterior distal area (22.5%) compared with socket flexion angle of $5^{\circ}$. $MP_{80+}$ during gait in socket flexion angle of $10^{\circ}$ decreased significantly in anterior distal area (34.1%) compared with socket flexion angle of $5^{\circ}$. Asymmetrical pressure change patterns in socket flexion angle of $0^{\circ}$ and $10^{\circ}$ were revealed in anterior proximal and distal region compared with socket flexion angle of $5^{\circ}$. To provide comfortable and safe socket for trans-tibial amputee, socket flexion angle must be considered.

• Wind and Structures
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• v.19 no.6
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• pp.623-647
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• 2014

In this paper, a probability distribution which is consistent with the observed phenomenon at the roof corner and, also on other portions of the roof, of a low-rise building is proposed. The model is consistent with the choice of probability density function suggested by the statistical thermodynamics of open systems and turbulence modelling in fluid mechanics. After presenting the justification based on physical phenomenon and based on statistical arguments, the fit of alpha-stable distribution for prediction of extreme negative wind pressure coefficients is explored. The predictions are compared with those actually observed during wind tunnel experiments (using wind tunnel experimental data obtained from the aerodynamic database of Tokyo Polytechnic University), and those predicted by using Gumbel minimum and Hermite polynomial model. The predictions are also compared with those estimated using a recently proposed non-parametric model in regions where stability criterion (in skewness-kurtosis space) is satisfied. From the comparisons, it is noted that the proposed model can be used to estimate the extreme peak negative wind pressure coefficients. The model has an advantage that it is consistent with the physical processes proposed in the literature for explaining large fluctuations at the roof corners.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.11
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• pp.53-58
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• 2015

Systemic heating and cooling air conditioning systems are popular in various industrial fields and even home. Recently, the rate of supply of this kind of multi-heat pump has been increased under ESCO financing supporting system. Generally the heat pumping system has a structural simplicity and easy installation benefits. and has good running efficiency under normal designed condition. But under extreme climate condition (over $+30^{\circ}C$, under $-10^{\circ}C$), this system exposes abnormal power consumption. It causes high progressive electric power rates and resultant peak power capacity of power plant. In this paper, a novel system concept of buffering refrigerant accumulator and constant pressure control system to relieve peak power load is proposed and this system's utility is verified with an prototype experimental system.

• Korean Journal of Materials Research
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• v.21 no.12
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• pp.690-696
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• 2011

In this study, nano-sized tin oxide powder with an average particle size of below 50 nm is prepared by the spray pyrolysis process. The influence of air pressure on the properties of the generated powder is examined. Along with the rise of air pressure from $0.1kg/cm^2$ to $3kg/cm^2$, the average size of the droplet-shaped particles decreases, while the particle size distribution becomes more regular. When the air pressure increases from $0.1kg/cm^2$ to $1kg/cm^2$, the average size of the dropletshaped particles, which is around 30-50 nm, shows hardly any change. When the air pressure increases up to $3kg/cm^2$, the average size of the droplet-shaped particles decreases to 30 nm. For the independent generated particles, when the air pressure is at $0.1kg/cm^2$, the average particle size is approximately 100 nm; when the air pressure increases up to $0.5kg/m^2$, the average particle size becomes more than 100 nm, and the surface structure becomes more compact; when the air pressure increases up to $1kg/cm^2$, the surface structure is almost the same as in the case of $0.5kg/cm^2$, and the average particle size is around 80- 100 nm; when the air pressure increases up to $3kg/cm^2$, the surface structure becomes incompact compared to the cases of other air pressures, and the average particle size is around 80-100 nm. Along with the rise of air pressure from $0.1kg/cm^2$ to $0.5kg/cm^2$, the XRD peak intensity slightly decreases, and the specific surface area increases. When the air pressure increases up to $1kg/cm^2$ and $3kg/cm^2$, the XRD peak intensity increases, while the specific surface area also increases.

• Phonetics and Speech Sciences
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• v.14 no.3
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• pp.11-25
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• 2022

From simultaneous recordings of the external photoglottography, intra-oral air pressure (P_io), airflow and acoustic data from four native Seoul Korean speakers (2 male and 2 female), we have found that the two fricatives are not significantly different in glottal opening peak and airflow peak height either word-initially or word-medially and that the duration of aspiration is significantly reduced in word-medial /s/, compared to those in word-initial /s/, not in /s'/. We have also found that the duration of a high P_io plateau is significantly longer in /s/ than in /s'/ both word-initially and word-medially and that airflow resistance (R=P_io/U) at the onset and offset of a P_io plateau and at the time of airflow peak height is significantly higher in /s'/ than in /s/ across the contexts. However, the differences in P_io peak and F0 are not significant. In addition, the transition time to reach airflow peak height from the offset of a P_io plateau is found to be significantly longer in /s/ than /s'/ in both word-initial and word-medial positions. No significant differences in glottal opening peak and airflow peak height confirm that /s/ is specified as [-spread glottis] like /s'/. As for the other significant differences, we propose that /s/ is [-tense], and /s'/ [+tense].

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.153-161
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• 1998

The knock in a spark ignition engine has been investigated to avoid the damage to the engine and unpleasant feeling caused by the pressure waves propagating across the combustion chamber. Knock intensity and knock onset angle were used as physical parameters to quantify the knock characteristics. The knock intensity is defined as a peak to peak value of the bank pass filtered combustion pressure signal and the knock onset angle is determined as the crank angle at which this signal exceeded the threshold level on each cycle. The cyclic variation of knock in four valve single cylinder engine was investigated with these two parameters. The location of autoignition was also examined by ion probes in the cylinder head gasket and squish region in the combustion chamber. For this measurement, a single cylinder engine was modified to accept the pressure transducer, 18 ion probes in the squish region and 8 ion probes in the specially designed PCB (Printed \ulcornerCircuit Board) cylinder head gasket.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.447-452
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• 1996

Realistic containment analyses for large LOCA using a merged torsion of RELAP5/CONTEMPT4 are conducted. Analyzed are Generic LOCA with respect to the mass and energy releases from the RCS and containment pressure and temperature behaviors. The break locations considered are the double-ended guillotine breaks at the RCP discharge and hot legs for UCN 3&4 plants. For discharge leg break. the predicted containment pressure and temperature reach a peak during blowdown phase, thereafter the pressure and temperature decrease gradually without the second reflood peak. For the hot leg break it is found that the bypass break flow through the broken steam generator-during post-blowdown is negligibly small so that the containment atmosphere is not pressurized after the end of blowdown.

• International Journal of Ocean System Engineering
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• v.3 no.4
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• pp.225-230
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• 2013

This paper introduces the experimental results of sloshing model tests carried out at Seoul National University. Two 1/50-scale tanks, i.e., 2D and 3D models with the same shape, were manufactured for the comparative study. Particular interest was taken in the differences in impact pressures between the 2D and 3D models. Regular motion tests were conducted for different filling depths. For each filling depth, 500 cycles of regular excitation were imposed at each frequency. To observe the characteristics and severity of sloshing from the acquired pressure data, statistical analyses were performed, not only for the peak pressure, but also for the area-concept indices, which represented the amount of impulse.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.47-55
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• 1998

A new ignition system concept was developed to improve ignition performance, accuracy of control and the reliability of the ignition system. The new ignition system has ho호 frequency discharge characteristics with 1.5-2.0 ms discharge duration, in place of the usual solitary longer duration event. We applied the system to a commercial engine to study its influence on the maximum combustion pressure attained during the cycle, when this peak pressure occurred, imep, variation rate of the engine speed and the flammability limit of a lean mixture. In this study, we clarified that the new ignition system had a beneficial effect of the lean mixture flammability limit. Also for a given mixture strength we found that the mew ignition system gave a higher peak cylinder pressure than in the case of the conventional ignition system.