• Journal of the Korean Geotechnical Society
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• v.20 no.6
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• pp.127-136
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• 2004

The soil arching in the backfill, which affects the magnitude and distribution of active earth pressure on a retaining wall, has also an effect on the stability and cross-sectional area of the retaining wall. In this study, results obtained from Paik's equation that includes arching effect on active earth pressure are compared with those from Coulomb theory to investigate the influence of the soil arching on active earth pressure, overturning moment, stability and cross-sectional area of translating rigid retaining walls. The comparisons show that the active forces including arching effects are always higher than those from Coulomb theory, irrespective of $\phi$ and $\delta$ values. The overturning moments, shear force and moment on the rigid wall are also higher when considering arching effects than when not considering arching effects. The deviation of shear forces and moments by including and excluding arching effects becomes maximum at the height of 0.02-0.08 times wall height from the base of the wall. Therefore, if a translating rigid retaining walls is designed based on Coulomb theory, the wall may reach sliding and overturning failures due to arching effect in the backfill and the cross-sectional area of the wall, especially at lower part of the wall, may not be sufficient to resist to shear force and moment.

• Geotechnical Engineering
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• v.13 no.5
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• pp.19-34
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• 1997

Classical earth pressure theories normally assume that ground condition remains uniform for considerable distance from the wall, and that the movement of the wall is enough to result in the development of an active pressure distribution. In the case of many low gravity walls in cut, constructed, for example, by using gabions or cribs, this is not commonly the case. In strong ground a steep temporary face will be excavated for reasons of economy, and a thin wedge of backfill will be placed behind the wall following its construetion. A designer then has the difficulty of selecting appropriate soil parameters and a reasonable method of calculating the earth pressure on the w리1. This paper starts by reviewing the existing solutions applicable to such geometry. A new silo and a wedge methods are developed for static and dynamic cases, and the results obtained from these are compared with two experimental results which more correctly mod el the geometry and strength of the wall, the fill, and the soil condition. Conclusions are drawn concerning both the magnitute and distribution of earth pressures to be supported by such walls.

• Journal of Powder Materials
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• v.17 no.5
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• pp.379-384
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• 2010

In the present work, bismuth nanopowders with various particle size distributions were synthesized by controlling argon (Ar) gas flow rate and chamber pressure of a gas condensation (GC) apparatus. From the analyses of transmission electron microscopy (TEM) images and nitrogen gas adsorption results, it was found that as Ar gas flow rate increased, the specific surface area of bismuth increased and the average particles size decreased. On the other hand, as the chamber pressure increased, the specific surface area of bismuth decreased and the average particles size increased. The optimum gas flow rate and chamber pressure for the maximized electrochemical active surface area were determined to be 8 L/min and 50 torr, respectively. The bismuth nanopowders synthesized at the above condition exhibit 13.47 $m^2g^{-1}$ of specific surface area and 45.6 nm of average particles diameter.

• Korean Journal of Medicinal Crop Science
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• v.22 no.5
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• pp.378-383
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• 2014

Curcuma longa L. leaf was extracted by water at $60^{\circ}C$ for 12 hours after being treatment of Ultra High Pressure under 500 MPa for 5-15 minute. The high pressure extraction for 15 minute (HPE15) was measured the highest extraction yield of 25.48% (w/w), compared to those from conventional extraction methods. The HPE15 showed the lowest cytotoxicity as 11.97% in adding $1.0mg/m{\ell}$ of concentration. Also, HPE15 was measured the highest inhibition of hyaluronidase as 44.48% in adding $1.0mg/m{\ell}$. In addition, The production of NO from macrophages was measured as $7.06{\mu}M$ in adding $1.0mg/m{\ell}$ of HPE15, which was lower than the those from others processes. Finally, HPE15 significantly reduced up to $649.44pg/m{\ell}$ of $ProstaglandinE_2$ production from UV-irradiation. These results suggest that the Curcuma longa Linne leaf extract from high pressure process might enhance the skin immune activities possibly by high elution of active components than other processes.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.609-614
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• 2015

Implanted telemetry systems provide the ability to monitor different species of animals while they move within their cages. Species monitored include mice, rats, rabbits, dogs, pigs, primates, sheep, horses, cattle, and others. A miniature transmitter implanted in each animal measures one or more parameters. Parameters measured include arterial pressure, intra-pleural pressure, left ventricular pressure, intra-ocular pressure, bladder pressure, ECG, EMG, EEG, EOG, temperature, activity, and other parameters and transmits the data via radio frequency signals to a nearby receiver. Every conventional dedicated transmitter contains one or more sensors, cpu and battery. Due to the expected life of the battery, the measuring time is limited. To overcome these problems, electromagnetic inductive coupling based wireless power transmission technology using multiple transmit coils were proposed, with each coil having a different active area driven by the coil driver. In this research, a parallel resonance based coil driver and serial resonance based coil driver are proposed. From the experiments we see that the parallel coil driver shows better performance under a low impedance and multiple coils configuration. However, the serial coil driver is more efficient for high impedance transmit coils.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.261-268
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• 1990

It has long been suggested that the cardiac atrium is a low pressure volume receptor controlling body fluid volume and blood pressure. Recently, the cardiac atrium has been found to contain a family of powerful peptides. To clarify the relationship between high blood pressure and the biologically active atrial peptides, experiments were done to define the characteristics of atrial natriuretic peptide secretion in the isolated perfused atria of renal hypertensive rats. Higher concentrations of plasma atrial natriuretic peptide and renin activity were observed in the two-kidney, one clip hypertensive rat compared to the normotensive rat. Atrial volume changes in response to pressure elevations were attenuated in hypertensive rats compared to normotensive rats. Incremental response to atrial volume changes in ANP secretion was accentuated in hypertensive rats. These date suggest that the accentuated atrial natriuretic peptide response to volume changes of hypertensive rats may be a physiological or pathphysiological adaptation to the high blood pressure and may be, at least in part, responsible for the elevated levels of plasma atrial natriuretic peptide observed in hypertensive rats.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.67-76
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• 2017

In this study, the effect of caisson heel on the active earth pressure is investigated. Using limit analysis method, inclinations of slip surface developed above the heel with different lengths are analyzed. The shorter the heel length, the larger those of inside slip surface, however those of outside slip surface are not changed. According to the relative heel length, relationships of internal friction angle of backfill material - wall friction angle between caisson structure and backfill - friction angle acting on virtual section at the end of heel are presented. Earth pressures acting against caisson structure with relatively short heel are smaller than Rankine earth pressure but always greater than Coulomb earth pressure which does not consider the heel length.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.149-157
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• 2014

In this paper, we investigated the sensitivity of aerostatic force coefficients of multi-layer radom in the various wind speeds. The test was conducted in KOCED Wind Tunnel Center in Chonbuk National University, and wind speeds were in the range from 5 m/s to 26 m/s in order to determine the Reynolds number independence. The test results of present multi-layer radom were not affected by the Reynolds number, The maximum positive pressure coefficient was found to be 1.08 at the center of the front of the plane in angle of attack of 0 degree, the maximum negative pressure coefficient was -2.03 at the upper right corner in angle of attack of 120 degree, while maximum drag coefficient was 1.11 in angle of attack of 180 degree.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.196-199
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• 2005

Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the loading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.28.2-28.2
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• 2021

We investigate the impact of ram pressure stripping due to the intracluster medium (ICM) on star-forming disk galaxies with a multiphase interstellar medium maintained by strong stellar feedback. We carry out radiation-hydrodynamic simulations of an isolated disk galaxy embedded in a 1011 M⦿ dark matter halo with various ICM winds mimicking the cluster outskirts (moderate) and the central environment (strong). We find that both star formation quenching and triggering occur in ram pressure-stripped galaxies, depending on the strength of the winds. HI and H2 in the outer galactic disk are significantly stripped in the presence of moderate winds, whereas turbulent pressure provides support against ram pressure in the central region, where star formation is active. Moderate ICM winds facilitate gas collapse, increasing the total star formation rates by ~40% when the wind is oriented face-on or by ~80% when it is edge-on. In contrast, strong winds rapidly blow away neutral and molecular hydrogen gas from the galaxy, suppressing star formation by a factor of 2 within ~200 Myr. Dense gas clumps with nH≳10 M⦿ pc-2 are easily identified in extraplanar regions, but no significant young stellar populations are found in such clumps. In our attempts to enhance radiative cooling by adopting a colder ICM of T=106K only a few additional stars are formed in the tail region, even if the amount of newly cooled gas increases by an order of magnitude.