• Composites Research
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• v.18 no.4
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• pp.1-7
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• 2005

In-situ structural health monitoring of filament wound pressure tanks were conducted during water-pressurizing test using embedded fiber Bragg grating (FBG) sensors. We need to monitor inner strains during working in order to verify the health condition of pressure tanks more accurately because finite element analyses on filament wound pressure tanks usually show large differences between inner and outer strains. Fiber optic sensors, especially FBG sensors can be easily embedded into the composite structures contrary to conventional electric strain gages (ESGs). In addition, many FBG sensors can be multiplexed in single optical fiber using wavelength division multiplexing (WDM) techniques. We fabricated a standard testing and evaluation bottle (STEB) with embedded FBG sensors and performed a water-pressurizing test. In order to increase the survivability of embedded FBG sensors, we suggested a revised fabrication process for embedding FBG sensors into a filament wound pressure tank, which includes a new protecting technique of sensor heads, the grating parts. From the experimental results, it was demonstrated that FBG sensors can be successfully adapted to filament wound pressure tanks for their structural health monitoring by embedding.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.71-78
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• 2012

The habitat suitability is an important factor to estimate the distribution and size of the physical habitat in river. This suitability is also a key factor to decide the ecological flow discharge for the fish. For the ecological analysis in river, accurate values of habitat suitability index for various fishes are necessary. In general, fish habitat is affected by the physical factor of the flow depth and velocity as well as the chemical and biological factors of nutrient and attached algae. Thus, the condition of the fish habitat is expected to be changed with each watershed and tributary. In this study, the habitat suitability indices for fishes were proposed by using the field monitoring data in the rivers of the Han and Geum river watersheds. The proposed indices for three fishes are compared: Zacco platypus, Zacco temminckii, and Coreoleuciscus splendidus. The results show that Zacco platypus has a similar distribution of habitat suitability index in two watersheds. Zacco temminckii and Coreoleuciscus splendidus, however, have different distributions with watersheds. Also, for Zacco platypus, the developed indices at three tributaries of the Han river are compared: Cheng-mi stream, Dal stream, and Hong-cheon stream. The comparision shows that the index in the Cheng-mi stream is different with those in the other rivers. This is expected to be because of a high nutrient concentration at the Cheong-mi stream.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.55-67
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• 2012

For the development of gas hydrate as new future energy resources, the drilling was carried out at the five locations where have high potential as gas hydrate bearing sediments in Ulleung basin, offshore Korea in 2007. Well log data were obtained from all wells and core data were procured from 3 wells, UBGH1-04, UBGH1-09 and UBGH1-10. In this study, user-friendly software, "KMU GH Logs 2010", is developed and this software is based on the estimation methods developed in previous study for gas hydrate bearing sediments and the properties estimated from UBGH1-04, UBGH1-09 and UBGH1-10. Petrophysical properties in un-cored wells, UBGH1-01 and UBGH1-14, are also estimated by using well log data. Porosity is estimated by density log and gas hydrate saturation is calculated by sonic log and resistivity log. Sedimentary facies are estimated by applying the linear discriminant analysis using both well log and sedimentary facies data from core analysis. It is confirmed that DITM facies and MSS facies appeared signs of gas hydrate disassociation are able to be distinguished by the method.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.411-421
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• 2014

The purpose of this study is to analyze the key factors that contribute to landslide causes through swelling clay minerals and terrain analysis in landslide sites taken place of in Yongin city, Gyeonggi-do, 2011. The study was conducted based on field survey by XRD (X-ray Diffraction), XRF (X-ray fluorescence), spectroscopic analysis on soil samples obtained from landslide sites and ASTER satellite image. Illite shows absorption features; $Fe^{2+}$ and $Fe^{3+}$ at 0.9 and $1.0{\mu}m$, broad water absorption features near 1.4 and $1.9{\mu}m$, and additional Al-hydroxyl features at 2.2, 2.3 and $2.4{\mu}m$, respectively. These absorption features are consistent with the bands 5, 6, and 7 of ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite image. Illite image was extracted using band math of $SWIR_{Illite}$. From these results, we confirmed the applicability of ASTER satellite image using identification of swelling clay minerals to landslide study.

• Development and Reproduction
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• v.4 no.1
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• pp.125-131
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• 2000

This study has used differential display-PCR, to amplify genes transcribed during the ovarian maturation induced by human chorionic gonadotropin (hCG). The cDNA expressed at the times of acquisition of oocyte maturational competence in red seabream (Pagrus major) following treatment with hCG was amplified and cloned. A full-length of cDNA for p. major was isolated using differential display-PCR and 5'RACE. This cDNA clone contained 2,662 nucleotides including the open reading frame that encoded 434 amino acids. Homology analyses, using the GenBank and EMBL general database searches, indicated that the nucleotides sequence of the cDNA does not have high homology with any other genes. This cDNA was judged to be a gene, which induction of maturational competence coincides with increase of mRNA related ovarian maturation. Consensus sequences which were consistent with protein kinase C phosphorylation sites and casein kinase II phosphorylation sites were identified. in vitro, the transcription level of mRNA related ovarian maturation increased between 9hr and 24hr following treatment of ovarian follicles with hCG. It was also increased after GtH-II (300 ng/ml) stimulation. Furthermore, in vivo, mRNA related ovarian maturation was rarely expressed prior to the acquisition of oocyte maturational competence, but was strongly expressed after the acquisition of oocyte maturational competence, suggesting that the hCG induction of maturational competence is brought about by the de novo synthesis of the mRNA related ovarian maturation in p. major.

• Economic and Environmental Geology
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• v.36 no.3
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• pp.149-157
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• 2003

Deep sea core samples were taken in the southwestern part of the Ulleung Basin in order to characterize the properties of shallow gases in the sediment. Amount of shallow gases in the sediments were calculated by head space techniques, and chemical and isotopic compositions of hydrocarbon gases were analyzed. Geochemical analyses were carried out on the gas bearing sediments to find out relationship between natural gas contents and organic characteristics of the sediments. Seismic characteristics of shallow gases in the sediments were also examined in this study. The amount of the hydrocarbon gases in the sediments range from 0.01% to 11.25%. Calculation of volume of gas per volume of wet sediment varies from 0.1 to 82.0 ml HC/L wet sediment. Methane consists 98% of the total hydrocarbon gases except for two samples. Based on the methane content and isotopic composition$(\delta^{13}c)$: -94.31$\textperthousand$~-55.5$\textperthousand$), the hydrocarbon gases from the sediments are generated from bacterial activities of methanogenic microbes. Contents of hydrocarbon gases are variable from site to site. Volume of shallow gases in the sediments shows no apparent trends vs. either characteristics of organic matter or particle sizes of the sediments. Gas concentration is high in the area of seismic anomalies such as blanking zone or chimney structures in the section. Physicochemically the pore water and the formation water systems are saturated with gases in these areas. Concentration of hydrocarbon gases in the sediments in these area shows favorable condition for generation of gas hydrate, as far as the other conditions are satisfied.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.155-162
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• 2007

Water balance is the major factor in forest ecosystem, and is closely related to the vegetation and topographic characteristics within a watershed. The hydrologic response of a forest watershed was investigated with the hydrological model. The deterministic, lumped parameter model (BROOK90) was selected and used to evaluate the applicability of the model for simulating daily runoff on the steep, forested watershed. The model was calibrated and validated against the streamflow data measured at the Bukmoongol watershed. The deviation in runoff volume $(D_v)$ was -1.7% for the calibration period, and the $D_v$ value for the validation period was 4.6%. The correlation coefficient (r) and model efficiency (E) on monthly basis were 0.922,0.847, respectively, for the calibration period, while the r- and E-value for the validation period were 0.941, 0.871, respectively. Overall, the simulated streamflows were close to the observations with respect to total runoff volume, seasonal runoff volume, and baseflow index for the simulation period. BROOK90 model was able to reproduce the trend of runoff with higher correlation during the simulation period.

• Research in Plant Disease
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• v.16 no.3
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• pp.247-253
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• 2010

Apple scar skin viroid (ASSVd) is one of the smallest viral pathogens infecting fruits, especially apple, and causes a significant damage to fruit trees. ASSVd usually induced the skin-dapple ring symptoms, but in 'Fuji' varieties, corked spot were occurred on the fruit skin in 2009. This new symptom will be of great helpful to diagnosis ASSVd in sight. ASSVd was surveyed in apple and pear from 2009 to 2010 in Korea, and ASSVd was identified in 20 out of 1,193 trees. The infection rate was 1.7%. To screen the infectivity of ASSVd among apple cultivars, real-time RT-PCR was applied followed by designing of ASSVd specific primers based on highly conserved regions of several ASSVd isolates including Korean isolate. NADH dehydrogenase subunit 5 (nad 5) gene, which is mRNA of the mitochondrial gene, was used for internal control. In this study, ASSVd infected apples were classified into 12 groups depending on different symptoms and symptom severity (scaring, rusting or malformation). Taken together, this study suggested that real-time PCR analysis was more sensitive to detect the low copy of ASSVd on early viroid infected apple skins than regular RT-PCR method.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.545-554
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• 2013

Augustine is an active stratovolcano located in southwest of Cook Inlet, about 290 kilometers southwest of Anchorage, Alaska. Between January 11 and 28, 2006, the volcano erupted explosively 14 times. We collected twelve permanent GPS stations operating by Plate Boundary Observatory (PBO) from 2005 to 2011. All data processing was carried out using Bernese GPS Software V5.0 with IGS precise orbit. Static baseline processing by fixing AC59 station was applied for the volcano activity monitoring. AC59 is the nearest (about 24.5 km) station to Augustine volcano, and located on North America Plate including Augustine Island. The test results show inflation (9.7 cm/yr) and deflation (-9.2 cm/yr) of volcano before and after eruption around crater clearly. After volcano activity has reached a plateau, some of the GPS stations installed north of the volcano show ground subsidence phenomenon caused by compaction of pyroclastic flows. These results indicate the possibility of using surface deformation observed by GPS for monitoring and prediction of volcano activity.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.294-298
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• 1993

The relationship between pH and the activity of ferrous iron in the reduced soil under water-logging was investigated theoretically and experimentally. The results of this study revealed, contrary to hitherto assumed, that the $pH-Fe^{+{+}}$ relationship in the commonly occurring rice soils under reduced condition is close to that in $FeCO_3-CO_2-H_2O$ system, being remote from that in $Fe_3(OH)_8-H_2O$ system and $Fe(OH)_2-H_2O$ system. This indicates that the activity of ferrous iron in the reduced rice soils under water-logging is likely to be governed by $FeCO_3$, neither by $Fe_3(OH)_8$, nor by $Fe(OH)_2$.