• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.3
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• pp.121-128
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• 2024

There are growing concerns that the recently implemented Earthquake Early Warning service is overestimating the rapidly provided earthquake magnitudes (M). As a result, the predicted damages unnecessarily activate earthquake protection systems for critical facilities and lifeline infrastructures that are far away. This study is conducted to improve the estimation accuracy of M by incorporating the observed S-wave seismograms in the near source region after removing the site effects of the seismograms in real time by filtering in the time domain. The ensemble of horizontal S-wave spectra from at least five seismograms without site effects is calculated and normalized to a hypocentric target distance (21.54 km) by using the distance attenuation model of Q(f)=348f^0.52 and a cross-over distance of 50 km. The natural logarithmic mean of the S-wave ensemble spectra is then fitted to Brune's source spectrum to obtain the best estimates for M and stress drop (SD) with the fitting weight of 1/standard deviation. The proposed methodology was tested on the 18 recent inland earthquakes in South Korea, and the condition of at least five records for the near-source region is sufficiently fulfilled at an epicentral distance of 30 km. The natural logarithmic standard deviation of the observed S-wave spectra of the ensemble was calculated to be 0.53 using records near the source for 1~10 Hz, compared to 0.42 using whole records. The result shows that the root-mean-square error of M and ln(SD) is approximately 0.17 and 0.6, respectively. This accuracy can provide a confidence interval of 0.4~2.3 of Peak Ground Acceleration values in the distant range.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2828-2834
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• 2024

This research intends to recycle bone and incorporate it into concrete for radiation shielding application using Phy-X/PSD software. Cement, sand and granite were mixed in proportion of 0.5 kg:1 kg:1 kg to obtain sample A. Other concretes composing of cement, sand, granite and bone ash was in proportion 0.45 kg:1 kg:1 kg:0.05 kg, 0.1 kg:1 kg:1 kg:0.4 kg and 0.35 kg:1 kg:1 kg:0.15 kg to obtain samples B, C and D respectively. 0.5 water-to-cement (W/C) ratio was adopted throughout the mixes because the control mix contain the normal water quantity for normal hydration of cement. Replacing the bone ash for the cement in the fabricated concretes enhances their densities where the fabricated concretes' density decreased from 2.33 g/cm³ to 2.22 g/cm³ by raising the reinforcing bones fly ash concentration from 0 to 0.15 kg. Additionally, increasing the bones fly ash concentration within the fabricated concretes increases their linear attenuation coefficient (LAC) where the fabricated concretes' μ values at 0.662 MeV reach 0.181 cm^-1, 0.178 cm^-1, 0.174 cm^-1, and 0.171 cm^-1, respectively for concretes A, B, C, and D. The use of other local materials is recommended, as it improves waste management being the major aim of the sustainable development goal.

• Journal of Soil and Groundwater Environment
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• v.8 no.4
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• pp.27-35
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• 2003

The study site located in an industrial complex has a Precambrian age gneiss as a bedrock. The poorly-developed, disturbed soils in the study site have loamy-textured surface soil (1 to 2 m) and gravelly sand alluvium subsurface (2 to 6 m) on the top of weathered gneiss bedrock. The depth of the groundwater table was about 3.5 m below ground surface and increased toward down-gradient of the site. The hydraulic conductivity of transmitted zone (gravelly coarse sand) was in the range of 5.0${\times}$10$\^$-2/∼1.85${\times}$10$\^$-1/ cm/sec. The fine sand layer was in the range of 1.5${\times}$10$\^$-3/ to 7.6${\times}$10$\^$-3/ cm/sec. and the reclaimed upper soil layer was less than 10$\^$-4/ cm/sec. Toluene, ethylbenzene, and xylene (TEX) was the major contaminant in the soil and groundwater. The average depth of the soil contamination was about 1.5 m in the gravelly sand alluvium layer. At the depth interval 2.4∼4.8 m, the highest contamination in the soil is located approximately 50 to 70 m from the suspected source areas. The concentration of TEX in the groundwater was highest in the suspected source area and a lesser concentration in the center and southwest parts of the site. The TEX distribution in the groundwater is associated with their distribution in the soil. Microbial isolation showed that Pseudomonas flurescence, Burkholderia cepacia, and Acinetobactor lwoffi were the dominant aerobic bacteria in the contaminated soils. The analytical results of the groundwater indicated that the concentrations of dissolved oxygen (DO), nitrate, and sulfate in the contaminated area were significantly lower than their concentrations in the none-contaminated control area. The results also indicated that groundwater at the contaminated area is under anaerobic condition and sulfate reduction is the predominant terminal electron accepting process. The total attenuation rate was 0.0017 day$\^$-1/ and the estimated first-order degradation rate constant (λ) was 0.0008 day$\^$-1/.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.732-737
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• 2008

This study developed a natural ingredient as a functional food possessing properties of attenuation of hypertension and cardiovascular hypertrophy. In a previous study hydrolysates obtained from chicken leg bone protein using Alcalase strongly inhibited angiotensin I converting enzyme (ACE) in vitro. In particular, hydrolysate (A4H) from four hours of incubation exhibited the highest ACE inhibitory activity (IC50 = 0.545 mg/ml). A4H was selected as a potent ACE inhibitor and orally administrated to spontaneously hypertensive rats (SHR) for eight weeks to investigate attenuating effects on age-related development of hypertension and cardiovascular hypertrophy. Results showed that treatment with A4H of SHRs attenuated the development of hypertension as effectively as the clinical antihypertensive drug captopril. Moreover, a significantly lower heart to body weight ratio and thinness of coronary arterial wall was observed in SHRs that had been treated with A4H or captopril. The results suggest that A4H can be utilized in developing an ACE inhibitor as a potential ingredient of functional foods to alleviate hypertension and cardiovascular hypertrophy.

• Economic and Environmental Geology
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• v.9 no.4
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• pp.213-223
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• 1976

Proceeding from general elementary principles to more specific abstract problems, we have attempted the rearrangement of the research results as they are known at present concerning the propagation and attennation of the elastic wave in submarine layers. We have derived the elementary equations of the elastic wave. In addition, the relationship of the propagation of the elastic waves in the sea water mass and the reflection of the waves from the water-sediment interface are treated and presented in different sections.

• The Korea Journal of Herbology
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• v.31 no.1
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• pp.1-5
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• 2016

Objectives : The purpose of this study was to investigate inhibitory effects of steamed Polygonatum odoratum extract (POE) on insulin resistance in rat skeletal muscle cells, L6 cells.Methods : Polygonatum odoratum (P. odoratum) extract was extracted with ethyl acetate. Activity of α-glucosidase in POE was measured for blood glucose regulation. MTT assay was examined for cell toxicity. Western blot analysis for measurement of adiponectine, peroxisome proliferator-activated receptorγ (PPARγ), insulin receptor substrate (IRS), glucose transporter 4 (Glut-4) and phosphorylation of serine/threonine-specific protein kinase (Akt) expressions were performed. Akt signaling pathway were analyzed with LY294002, which is a specific PI3K/Akt inhibitor.Results : The results revealed that POE inhibited α-glucosidase activity. Treatment of POE in L6 cells inhibited the differentiation of L6 cells compared to those of vehicl control. Additionally, protein expressions of adiponectine, PPARγ, IRS and Glut-4 were significantly regulated compared to those of vehicle control (p < 0.05), respectively. Futhermore, phosphorylation of Akt was increased in L6 cells treated with POE compared to that of vehicle control (p < 0.05). pAkt expression was significantly accentuated with Akt inhibitor (LY294002).Conclusions : These results suggest that POE may have potential as a natural agent for prevention/improvement of diabetes, especially, regulation of blood glucose. Therefore, further additional study should be conducted to elucidate in depth the pharmaceutical efficacy of these.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.561-564
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• 2008

Concrete is considered to be one of the excellent and versatile shielding material and is widely used for the radiation shielding material. Specially, heavyweight(or high density) concrete is used in counter weights of bascule and lift bridges, but it is generally used in radiation shielding structures and differ from normal weight concrete by having a higher density and special compositions to improve its attenuation properties. Thorough examination and evaluation of heavyweight aggregate sources are necessary to obtain material suitable for the type of shielding required. Therefore, this paper aims to study mechanical properties of heavyweight concrete by using normal cement, natural and heavyweight aggregate.

• Advances in Traditional Medicine
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• v.7 no.1
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• pp.94-99
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• 2007

The present study is aimed at finding the effect of B-20 drops, a homoeopathic formulation, in streptozotocin (STZ) induced diabetic rats. B-20 drops comprises of the constituents derived from plants and other natural sources, and are generally prescribed by the homoeopathic physician, in cases of hyperglycemia and diabetes. The elevated levels of fasting blood glucose and pancreatic lipid peroxides observed in rats treated with STZ were significantly reduced by the treatment of B-20 drops. The reduced liver glycogen contents were also brought back to near normal level by B-20 drops treatment in STZ diabetic rats. STZ induced histopathological changes in pancreas and liver was also partially reversed by B-20 drops. The findings indicate that B-20 drops help in improving the glycogen stores in the liver and prevents STZ induced damage through free radicals by decreasing the pancreatic lipid peroxides levels.

• Journal of Soil and Groundwater Environment
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• v.21 no.3
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• pp.88-94
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• 2016

The simultaneous biodegradation between MTBE (Gasoline additives) and BTEX (Benzene, Toluene, Ethyl-benzene, o-Xylene, m-Xylene, p-Xylene) was achieved within a competitive inter-relationship, with not only electron accepters such as nitrate, sulfate, and iron(III) without oxygen, but also with electron donors such as MTBE and BTEX. Preexisting indigenous microorganisms from a domestic sample of gasoline contaminated soil was used for a lab-scale batch test. The result of the test showed that the biodegradation rate of MTBE decreased when there was co-existing MTBE and BTEX, compared to having just MTBE present. The growth of indigenous microorganisms was not affected in the case of the MTBE treatment, whereas the growth of the microorganisms was decreased in combined MTBE and BTEX sample. This may indicate that an inhibitor related to biodegradation when BTEX and MTBE are mixed will be found. This inhibitor may be found to retard the anaerobic conditions needed for efficient breakdown of these complex carbon chain molecules in-situ. Moreover, it is also possible that an unknown competitive reaction is being imposed on the interactions between MTBE and BTEX dependent on conditions, ratios of mixture, etc.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.5
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• pp.37-42
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• 1983

The elliptic functions have transmission zeros on the imaginary axis and exhibit equal ripples in the stopband as well as in the passband. As a consequence they can be made optimal in the sense that the transition band is minimal. However the time domain behaviors turned out to be inferior to those of Chebyshev and Butterworth responses. This paper investigates the unit step responses and impulse responses in order to analyze the effects of various parameters such as passband attenuation, stopband frequencies M. etc., The following are the prominent features. Step responses of elliptic filters rise faster and produce larger overshoots and undershoots with higher natural frequencies. In the case of even functions, the initial values are non-zero which decreases as $\omega$s increases. Unlike Butter-worth or Chebyshev cases the impulse responses start with nonzero valses which also decrease as $\omega$s or order of the function increases. Eight figures are included to illustrate above analysis.