• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.383-389
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• 2003

Clay minerals show a distinct induced-polarization phenomenon, which is one of the most important factors for predicting groundwater flow and contaminant transport. This paper presents a step-by-step process to estimate Cole-Cole parameters from spectral induced-polarization (IP) data measured on the surface of three-dimensional earth. First, the inversion of low-frequency resistivity survey data is made to identify the dc resistivity ${\rho}_dc$ of a volume having IP effects. The other parameters, chargeability m, time constant $\tau$, and frequency dependence c, are sought for the polarizable volume. Next, using multi-frequency data, c can be obtained as high or low asymptotes of the slope of log phase vs. log frequency. Further, for low m, intrinsic $\tau$ is approximated by apparent one, ${\tau}_a$, which is derived from the relation ${{\omega}{\tau}}_a$=1 at an angular frequency $\omega$, where the imaginary component of spectral IP data has an extreme value. Finally, to obtain intrinsic m a two-step linearized procedure has been derived. For a body of given $\tau$ and c, forward modeling with a progression of m values yields a plot of observed vs. intrinsic imaginary components for a frequency. Since this plot is essentially linear, to extract the intrinsic imaginary component is quite simple with an observed value. Using the plot of intrinsic imaginary component vs. m, intrinsic m is determined. We present a synthetic example to illustrate that the Cole-Cole parameters can be recovered from spectral IP data.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.470-478
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• 2013

There have been a number of observed precursors of volcanic activities- such as volcanic earthquake, surface inflation, specific volcanic gas emission, temperature of hot spring- at Mt. Baekdusan since 2002. We identified the increase of the volume of magma chamber beneath Mt. Baekdusan as we observed an inflation trend of vertical and horizontal surface displacement around Cheonji caldera lake by using precise leveling data from 2002 to 2009. The surface displacement trend changed to deflation in 2010, and the trend changed to inflation again after a while. Utilizing the data of inflated surface (46.33 mm) on the northern slope of Mt. Baekdusan from 2002 to 2003, we calculated the volume change of magma chamber beneath the Mt. Baekdusan. The volume change was about 0.008 $km^3$ ($7.7-8.0{\times}10^6m^3$) from 2002 to 2003. It indicated that a new magma (0.008 $km^3$) injected to the magma chamber 5 km below Mt. Baekdusan.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.233-233
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• 2015

Vu Gia - Thu Bon basin is located in central Vietnam between Truong Son mountain range on the border with Lao in the west and the East Sea in the east. The basin occupies about 10,350 km2 or roughly 90% of the Quang Nam Province and includes Da Nang, a very large city with about 876,000 inhabitants. Total annual rainfall ranges from about 2,000 mm in central and downstream areas to more than 4,000 mm in southern mountainous areas. Rainfall during the monsoon season accounts for 65 to 80% of total annual rainfall. The highest amount of rainfall occurs in October and November which accounts for 40 to 50% of the annual rainfall. Rainfall in the dry season represents about 20 to 35% of the total annual rainfall. The low rainfall season usually occurs from February to April, accounting for only 3 to 5% of the total annual rainfall. The mean annual flow volume in the basin is $19.1{\times}109m 3$. Similar to the distribution of rainfall, annual flows are distinguished by two distinct seasons (the flood season and the low-flow season). The flood season commonly starts in the mid-September and ends in early January. Flows during the flood season account for 62 to 69% of the total annual water volume, while flows in the dry season comprise 22 to 38% of total annual run-off. The water volume gauged in November, the highest flow month, accounts for 26 to 31% of the total annual run-off while the driest period is April with flows of 2 to 3% of the total annual run-off. There are some hydropower projects in the Vu Gia - Thu Bon basin as the cascade of Song Bung 2, Song Bung 4, and Song Bung 5, the A Vuong project currently under construction, the Dak Mi 1 and Dak Mi 4 projects on the Khai tributary, and the Song Con project on the Con River. Both the Khai tributary and the Song Con join the Bung River downstream of SB5, although the Dak Mi 4 project involves an inter-basin diversion to Thu Bon. Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, data from the Vu Gia - Thu Bon River Basin in the central of Viet Nam were analyzed to investigate changes in annual runoff during the period of 1977-2010. The nonparametric Mann-Kendall test and the Mann-Kendall-Sneyers test were used to identify trend and step change point in the annual runoff. It was found that the basin had a significant increasing trend in annual runoff. The hydrologic sensitivity analysis method was employed to evaluate the effects of climate variability and human activities on mean annual runoff for the human-induced period based on precipitation and potential evapotranspiration. This study quantitatively distinguishes the effects between climate variability and human activities on runoff, which can do duty for a reference for regional water resources assessment and management.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.998-1003
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• 2008

It has been recognized unsaturated soil behaviour playing an important role in geomechanics. Up to now, only a few experimental data are available for the technical difficulties related to both volume changes and suction measurements. In this study, the volume changes of unsaturated compacted silty soil were monitored with proximeter (i.e. non-contactable transducer) during various triaxial compression tests, which gave a realistic estimation in the volume changes of unsaturated soil sample. Various triaxial compression tests for unsaturated soil under different drainage conditions are carried out. The behaviour of the pore pressure, namely, the pore-air pressure and the pore-water pressure, and matric suction during the shearing tests are investigated. The experimental results have revealed that the mechanical behaviour of unsaturated soil can be significantly affected by the matric suction.

• Journal of Environmental Science International
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• v.21 no.9
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• pp.1149-1162
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• 2012

The impact of a considerable increase in traffic volume on the emission and concentrations of air pollutants was investigated at three beaches (Haeundae (HB), Gwanganri (GB), and Songjeong (SB)) in Busan during beach opening period (BOP) in 2011. During the BOP, passenger car was the major vehicle type, followed by taxi, and van. CO was the major contributor of total air pollutant emissions followed by NOx, VOC, and $PM_{10}$. For the temporal variation of the emission of air pollutants during the BOP, it was generally the highest in the afternoon followed by the evening and morning, except for SB. For the spatial variation of their emission, it was the highest at GB followed by SB and HB. The emissions of air pollutants during the BOP were generally higher than those during the Non-BOP, except for HB. In contrast, the significant impact of the traffic volume increase on the concentrations of air pollutants at monitoring sites near the three beaches during the BOP were not found compared to the Non-BOP due to the significant distances between monitoring sites of air pollutants and monitoring sites of traffic volume at the beaches.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.509-512
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• 2009

Powder diffraction patterns of the zeolite mesolite ($Na_{5.33}Ca_{5.33}Al_{16}Si_{24}O_{80}{\cdot}21.33H_2O$), with a natrolite framework topology were measured as a function of pressure up to 5.0 GPa using a diamond-anvil cell and a $200{\mu}m$-focused monochromatic synchrotron X-ray. Under the hydrostatic conditions mediated by pore-penetrating alcohol and water mixture, the elastic behavior of mesolite is characterized by continuous volume expansion between ca. 0.5 and 1.5 GPa, which results from expansion in the ab-plane and contraction along the c-axis. Subsequent to this anomalous behavior, changes in the powder diffraction patterns suggest possible reentrant order-disorder transition. The ordered layers of sodium- and calcium-containing channels in a 1:2 ratio along the b-axis attribute to the $3b_{natrolite}$ cell below 1.5 GPa. When the volume expansion is completed above 1.5 GPa, such characteristic ordering reflections disappear and the $b_{natrolite}$ cell persists with marginal volume contraction up to ca. 2.5 GPa. Further increase in pressure leads to progressive volume contraction and appears to generate another set of superlattice reflections in the $3c_{natrolite}$ cell. This suggests that mesolite in the pressure-induced hydration state experiences order-disorder-order transition involving the motions of sodium and calcium cations either through cross-channel diffusion or within the respective channels.

• Journal of the Mineralogical Society of Korea
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• v.30 no.3
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• pp.83-91
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• 2017

In-situ high-pressure and ex-situ high temperature-pressure experiments of natural beryl ($Be_3Al_2Si_6O_{18}$, P6/mcc) from two different localities (beryl-A and beryl-B) were studied using pure water as pressure transmitting medium. Compared to the previous study using a mixture of methanol:ethanol medium in 4 : 1 by volume, pressure- and temperature-induced chemical and structural changes under water medium are expected to be different. The derived bulk moduli are 111(7) GPa, $K{_0}^{\prime}=73(7)$; 110(9) GPa, $K{_0}^{\prime}=65(8)$ for beryl-A and beryl-B, respectively. We observe densifications in volume compression, which appear to be attributed to the phase transitions of water to ICE VI and ICE VII around 1.0 GPa and 2.5 GPa, respectively.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.159-169
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• 2004

This is a proposal to probe local part of the interplanetary dust (IPD) cloud complex and retrieve mean volume emissivity of the local IPDs at mid-infrared wavelengths. This will be done by monitoring, with Infrared Camera (IRC) aboard the ASTRO-F, the annual modulation of the zodiacal emission. In pointing mode of the ASTRO-F mission the spacecraft can make attitude maneuvering over approximately ${\pm}1^{\circ}$ range centered at solar elongation $90^{\circ}$ in the ecliptic plane. The attitude maneuvering combined with high sensitivity of the IRC will provide us with a unique opportunity observationally to take derivatives of the zodiacal emission brightness with respect to the solar elongation. From the resulting differential of the brightness over the ${\pm}1^{\circ}$ range, one can directly determine the mean volume emissivity of the local IPDs with a sufficient accuracy to de-modulate the annual emissivity variations due to the Earth's elliptical motion and the dis-alignment of the maximum IPD density plane with respect to the ecliptic. The non-zero eccentricity ($e_{\oplus}$= 0.0167) of the Earth's orbit combined with the sensitive temperature dependence of the Planck function would bring modulations of amplitude at least $3.34\%$ to the zodiacal emission brightness at mid-infrared wavelengths, with which one may determine the IPD temperature T(r) and mean number density n(r) as functions of heliocentric distance r. This will in turn fix the power-law exponent $\delta$ in the relation $T(r) = T_o(r/r_o)^{-\delta}$ for the dust temperature and v in $n(r) = n_o(r/r_o)^-v$ for the density. We discuss how one may de-couple the notorious degeneracy of cross-section, density, reference temperature $T_o$ and exponent $\delta$.

• Textile Coloration and Finishing
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• v.33 no.4
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• pp.317-326
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• 2021

In this study, we investigated for Bio-EPDM foam with oyster shell surface modified earth coupling agent. Experiments were carried out to confirm the bio-EPDM/Oyster shell foam applying content of earth coupling agent. The cure characterization were evaluated by measuring the mooney viscosity and oscillating disc rheometer (ODR). Mechanical properties such as hardness, tensile strength, elogation at break and tear strength were measured, and changes of mechanical properties were also evaluated after immersion in NaCl solution. In addition degree of volume change was measured after immersing the Bio-EPDM foam in NaCl solution and the low-temperature permanent compression set was evaluated at 4℃. To evaluate the low-temperature characteristics of Bio-EPDM/Oyster shell, the glass transition temperature was measured using Differential Scanning Calorimeter (DSC). As a result as the content of the earth coupling agent increased up to 3phr, the crosslinking density and mooney viscosity increased, and the mechanical properties and low-temperature permanent compression set improved, but from 4phr, it was rather decreased. The change in the glass transition temperature was insignificant, and the foam cell appeared to be uniform when the earth coupling agent was applied.

• Journal of Environmental Science International
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• v.23 no.1
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• pp.69-79
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• 2014

The seasonal variation of pH and ion components in precipitation were investigated from January to December 2009 at Busan, Korea. The precipitation was acidic with a volume-weighted mean pH concentration of 5.32, which ranged from 3.79 to 8.66. The volume-weighted mean conductivity showed 86.77 ${\mu}S/cm$ and indicated higher concentration about 96.69 ${\mu}S/cm$ in summer. The volume-weighted mean equivalent concentration of components followed the order: $K^+$ > $Ca^{2+}$ > $nss-Ca^{2+}$ > $NH_4^+$ > $Mg^{2+}$ > $Na^+$ > $Li^+$ in cations and $Cl^-$ > $SO_4^{2-}$ > $nss-SO_4^{2-}$ > $NO_3^-$ > $NO^{2-}$ > $F^-$ > $Br^-$ in anions. Particularly, concentration of $K^+$ and $Cl^-$ showed 56 and 78 % in cations and anions. The higher concentration in $K^+$, $Na^+$, $Mg^{2+}$ and $Cl^-$ were shown in Busan city as compared to the other cities. The neutralization factors have been found to have higher value for potassium ion in winter compared with different seasons, indicating significant neutralization of acidic components over the region by potassium. Therefore, the precipitation characteristics at Busan had both continental and coastal as consequence of pH, conductivity and ionic analyses.