• Geophysics and Geophysical Exploration
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• v.18 no.4
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• pp.223-231
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• 2015

Self-potential (SP) is sensitive to groundwater flow and there are many causes to generate SP. Among many mechanisms of SP, pore-fluid flow in porous media can generate potential without any external current source, which is referred to as electrokinetic potential or streaming potential. When calculating SP responses on the surface due to geothermal fluid within an engineered geothermal system (EGS) reservoir, SP anomaly is usually considered to be generated by fluid injection or production within the reservoir. However, SP anomaly can also result from geothermal water fluid within EGS reservoirs experiencing temperature changes between injection and production wells. For more precise simulation of SP responses, we developed an algorithm being able to take account of SP anomalies produced by not only water injection and production but also the fluid of geothermal water, based on three-dimensional finite-element-method employing tetrahedron elements; the developed algorithm can simulate electrical potential responses by both point source and volume source. After verifying the developed algorithm, we assumed a simple geothermal reservoir model and analyzed SP responses caused by geothermal water injection and production. We are going to further analyze SP responses for geothermal water in the presence of water production and injection, considering temperature distribution and geothermal water flow in the following research.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.67-67
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• 2006

• Progress in Medical Physics
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• v.22 no.2
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• pp.79-84
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• 2011

In this study, Geant4 based Monte Carlo simulations were carried out for medical linear accelerator. Modified Medical Linac2 toolkit was used for calculation. The energy spectrum, most probable energy and the photon mean energy compared with the published results using the EGS4 code. The results well agreed with published results. The calculated results of photon fluence, energy fluence and mean energy according to the radius from the centre of the beam were analyzed. Monte Carlo simulation using Medical Linac2 code is considered to be useful for analysis of medical linear accelerator. Because the calculated results varies depending on Physics List model for same head structure. It it important to choose the right model for research purpose. Monte Carlo simulation using GEANT4 Medical Linac2 is a valuable for any novice to adopt this code to the study related to 6 MV photon fluence from medical linear accelerator.

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.45-52
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• 2007

To evaluate the feed value of starfish, antimicrobial effects of its extract, nutrients contents, concentration of amino acids and its bioavailability were tested. Steaming and ether processes were applied to obtain the extract from starfish for antimicrobial effects examination. The starfish was dried at $60^{\circ}C$ for 3 days before grinding for processing and fermentation. Ground starfish(GS), extruded starfish(ES), fermented starfish(EFS) were added with enzyme and without enzyme(Non enzyme fermented starfish : NEFS). Then the nutrient composition and bioavailability of those were analyzed. The extract from starfish showed no inhibition of the growth of lactobacillus and pathogenic bacteria. Protein content showed significantly higher 62.86% and 52.82%, respectively in EFS and NEFS than GS and EGS(p<0.05). The Ca content of GS, EGS, EFS and NEFS was 17.26%, 18.26%, 5.37% and 8.55%, respectively. It was low in EFS and NEFS due to measure the Ca content after fermentation. Total amino acid was 17.17 mg/g, 20.28 mg/g, 36.30 mg/g and 29.96 mg/g in GS, EGS, EFS and NEFS, respectively. The ratio of total amino acid to protein tended to show the similar tendency as total amino acid. Both total amino acid and its ratio to protein were increased by the fermentation. Bioavailability of the protein and Ca showed more 80% in EFS and NEFS. The nutrients availability of EFS were significantly higher in laying hens than other treatments. The results of these experiments indicate that starfish would be applied as a feed ingredients if it was properly treated.

• Journal of Oral Medicine and Pain
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• v.9 no.1
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• pp.23-28
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• 1984

Author could get the result as below after EGS(an electrical nerve stimulator) treatment, one of the pain-reliaving methods, to 30 patients in whom author could confirm the objective improvement of symptoms among the patients who visited SNUH between July the first and December the 31th. 1984. because of TMJ pain. 1. The average number of treatment were 5.5 times/pt., and mean treatment duration was 20 minutes. 2. The severities of pain before the treatment were distressing (46.7%), discomforting (26.7%), mild (20.0%) and horrible (6.7%), but the percentages of them became changed to mild (50%), discomforting (33.3%), none (10%) and distressing (6.7%) after treatment. 3. The activities of mouth opening before the treatment were moderately restricted (53.3 %), serverely restricted (33.3%) and slightly restricted (13.3%), but the percentages of them became changed to slightly restricted (66.7%), normal (16.7%), modorately restricted (13.3%) and severely restricted (3.3%) after treatment. 4. The effects of the pain upon one's personality before treatment were severely upset (43.3%), moderately upset (36.7%), slightly upset(16.7%) and normal (3.3%), but the percentages of them became changed to slightly upset (50%), normal (33.3%), morderately upset (10%) and severely upset (6.7%) after treatment.

• Progress in Medical Physics
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• v.19 no.1
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• pp.21-34
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• 2008

The parallel Monte Carlo electron and photon transport (PMCEPT) code [Kum and Lee, J. Korean Phys. Soc. 47, 716 (2006)] for calculating electron and photon beam doses has been developed based on the three dimensional geometry defined by computed tomography (CT) images and implemented on the Beowulf PC cluster. Understanding the limitations of Monte Carlo codes is useful in order to avoid systematic errors in simulations and to suggest further improvement of the codes. We evaluated the PMCEPT code by comparing its normalized depth doses for electron and photon beams with those of MCNP5, EGS4, DPM, and GEANT4 codes, and with measurements. The PMCEPT results agreed well with others in homogeneous and heterogeneous media within an error of $1{\sim}3%$ of the dose maximum. The computing time benchmark has also been performed for two cases, showing that the PMCEPT code was approximately twenty times faster than the MCNP5 for 20-MeV electron beams irradiated on the water phantom. For the 18-MV photon beams irradiated on the water phantom, the PMCEPT was three times faster than the GEANT4. Thus, the results suggest that the PMCEPT code is indeed appropriate for both fast and accurate simulations.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.297-303
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• 2017

Leucine-responsive regulatory protein (LRP) is a regulatory protein of molecular weight 18.8 kDa and is widely known to regulate many metabolic and functional activities of operons in Escherichia coli. The gene for Lrp from Escherichia coli in pQE system of 6 ${\times}$ His-tagging was expressed and $^3H$-labeled protein, as well as the wild type Lrp, was purified. The crosslink experiments were performed to analyze the quaternary structure of Lrp at high of $5{\mu}M$ and at low concentrations below $0.3{\mu}M$ with cross linkers, such as glutaraldehyde, 1, 2, 3, 4-diepoxy-butane (DEB), and ethylene glycol bis (succinimidyl succinate) (EGS). In the experiments, we found that the Lrp protein can be formed higher conformation states of tetramer, hexamer, octamer, as well as dimeric state when incubated with the above cross linkers.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.271-273
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• 2001

In precise measurement of air kerma with cavity ionization chambers, the effect of wall attenuation and scatter are corrected by Kwall and that of nonuniformity by Knu. Using the EGS4 code, we calculated these two correction factors. Correction factors calculated for two different-sized cylindrical ionization chamber differ by up to 0.7% from those obtained by measurements.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.166-171
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• 2013

While high-dose ionizing radiation results in long term cellular cytotoxicity, chronic low-dose (<0.2 Gy) of X- or ${\gamma}$-ray irradiation can be beneficial to living organisms by inducing radiation hormesis, stimulating immune function, and adaptive responses. During chronic low-dose-rate radiation (LDR) exposure, whole body of mice is exposed to radiation, however, it remains unclear if LDR causes changes in gene expression of the whole brain. Therefore, we aim to investigate expressed genes (EGs) and signaling pathways specifically regulated by LDR-irradiation ($^{137}Cs$, a cumulative dose of 1.7 Gy for total 100 days) in the whole brain. Using microarray analysis of whole brain RNA extracts harvested from ICR and AKR/J mice after LDR-irradiation, we discovered that two mice strains displayed distinct gene regulation patterns upon LDR-irradiation. In ICR mice, genes involved in ion transport, transition metal ion transport, and developmental cell growth were turned on while, in AKR/J mice, genes involved in sensory perception, cognition, olfactory transduction, G-protein coupled receptor pathways, inflammatory response, proteolysis, and base excision repair were found to be affected by LDR. We validated LDR-sensitive EGs by qPCR and confirmed specific upregulation of S100a7a, Olfr624, and Gm4868 genes in AKR/J mice whole brain. Therefore, our data provide the first report of genetic changes regulated by LDR in the mouse whole brain, which may affect several aspects of brain function.

• Geophysics and Geophysical Exploration
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• v.18 no.4
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• pp.232-240
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• 2015

Magnetotelluric (MT) survey investigates electrical structure of subsurface by measuring natural electromagnetic fields on the earth surface. For the accurate interpretation of MT data, the precise three-dimensional (3-D) modeling algorithm is prerequisite. Since MT responses are affected by electrical anisotropy of medium, the modeling algorithm has to incorporate the electrical anisotropy especially when analyzing time-lapse MT data sets, for monitoring engineered geothermal system (EGS) reservoir, because changes in different-vintage MT-data sets are small. This study developed a MT modeling algorithm for the simulation MT responses in the presence of electrical anisotropy by improving a pre-existing staggered-grid finite-difference MT modeling algorithm. After verifying the developed algorithm, we analyzed the effect of vertical transversely isotropic (VTI) anisotropy on MT responses. In addition, we are planning to extend the applicability of the developed algorithm which can simulate not only the horizontal transversely isotropic (HTI) anisotropy, but also the tiled transversely isotropic (TTI) anisotropy.