• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.79-84
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• 2002

The main cause factor for effective the output, especially in small & irregular shaped field of electron beam therapy, are collimation system, insert block diameter and energy. In the absorption deose of treatment fields, we should consider the lateral build-up ratio (LBR), which the ratio of dose at a point at depth for a given circular field to the dose at the same point for a 'broad-field', for the same incident fluence and profile. The LBR data for a small circular field are used to extract radial spread of the pencil beam, ${\sigma}$, as a function of depth and energy. It's based on elementary pencil beam. We consider availability of the factor, ${\sigma}$, in the small & irregular fields electron beam treatment.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.4
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• pp.199-211
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• 1997

As a part of study on geological disposal of radioactive waste, hydrogeochemical characteristics of deep granitic groundwater in Korea were investigated through the construction of a large geochemical dataset of natural water, the examination on the behaviour of dissolved constituents, and the consideration of phase stability based on thermodynamic approach. In granitic region, the contents of total dissolved solids increase progressively from surface waters to deep groundwaters, which indicates the presence of more concentrated waters at depth due to water-rock interaction. The chemical composition of groundwater evolves from initial $Ca^{2＋}$－(C $l^{－}$＋S $O_4$$^{2-}$) or $Ca^{2＋}$-HC $O_3$$^{－}$ type to final N $a^{＋}$-HC $O_3$$^{－}$ or N $a^{＋}$－(C $l^{－}$＋S $O_4$$^{2-}$) type, via $Ca^{2＋}$-HC $O_3$$^{－}$ type. Three main mechanisms seem to control the chemical composition of groundwater in the granitic region; 1) congruent dissolution of calcite at shallower depth, 2) calcite precipitation and incongruent dissolution of plagioclase at deeper depth, and 3) kaolinite-smectite or/and kaolinite-illite reaction at equilibrium at deeper depth. The behaviour of dissolved major cations (C $a^{2＋}$, $K^{＋}$, $Mg^{2＋}$, M $a^{＋}$) and silica is likely to be controlled by these reactions.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.369-374
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• 2015

This study was conducted to compare the glucose, lactate, and nucleotide degradation products content of cooked beef steaks from Korean Hanwoo (quality grade: 1) and Australian cattle (Bos indicus, grain-fed for 100 d) by internal temperature. The loins (M. longissimus dorsi) and top rounds (M. semimembranosus) from two cattle breeds were cut into about 2 cm thickness and then cooked in a $180^{\circ}C$ electronic oven until internal temperature attained to 50, 70, or $90^{\circ}C$. Regardless of internal temperature, glucose content was higher (P<0.05) in cooked loin and top round steaks from Hanwoo compared to those from Australian cattle. Lactate content was shown to be lower (P<0.05) in cooked steaks from Hanwoo than in those from Australian cattle. Lower (P<0.05) hypoxanthine and higher (P<0.05) guanosine 5'-monophosphate, inosine 5'-monophosphate, inosine contents were observed in cooked steaks from Hanwoo. Furthermore, glucose content tended to be decreased by internal temperature but nucleotide degradation products content was not changed by internal temperature. Therefore, these findings suggest that cooked Hanwoo beef steaks had higher flavor precursors related to sweet and umami tastes than cooked Australian beef steaks

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.749-757
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• 2006

Many losses of life and extensive damage of social infrastructures have occurred due to moderate and strong earthquakes all over the world. In this research various design parameters have been evaluated to develop a rational seismic design code of rectangular reinforced concrete(RC) bridge piers. It was confirmed from this study that the axial force ratio and longitudinal steel ratio were most influencing design parameters on the seismic displacement ductility from experimental results of 54 rectangular RC bridge piers, which were tested at domestic and foregin countries. However, these important parameters are not considered in the confinement steel ratio of Korea Highway Bridge Design Specification(KHBDS). The objective of this study is to propose a rational design provision for the transverse reinforcement of rectangular RC bridge piers. New confinement steel ratio is proposed by reflecting the effect of the axial force and longitudinal steel into the current code of KHBDS. furthermore, minimum transverse confinement steel ratio is also proposed to avoid a probable buckling of longitudinal reinforcing steels of RC bridge piers with a relatively low axial force. New practical code can alleviate the rebar congestion in the plastic hinge region of RC bridge pier, which contributes to construct RC bridge piers in a simple and economic way.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.391-405
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• 2005

Chemical and isotopic analysis for stream water, shallow groundwater, intermediate groundwater and deep groundwater was carried out to grasp hydrogeochemical characteristics of groundwater in the Heunghae area, Pohang city. Water type of stream water and shallow groundwaters is typified as Ca-Cl type, intermediate groundwater is $Na-HCO_3$, and deep groundwater is prominent in Wa-Cl type. $HCO_3^-\;and\;SiO_2$ in shallow groundwater are originated from weathering of silicate minerals, whereas those of deep groundwaters are resulted from weathering of carbonate minerals. Ca and Mg ions in both shallow and deep groundwaters are resulted from weathering of calcite and dolomite. $SO_4^{2-}$ in shallow groundwater is originated mainly from pyrite oxidation. As well depth increases, pH and TDS increase, but Eh and DO decrease. Alkali metal contents(K, Na, Li) increases as well depth increases, but alkali earth metal(Mg, Ca) and hi concentrations increase as well depth decreases. Anions, halogen elements(F, Cl, Br), and $HCO_3$ contents increase as well depth increases. The average stable isotope value of the groundwater of each depth is as follows; deep groundwater: ${\delta}^{18}O=-10.1\%o,\;{\delta}D=-65.8\%_{\circ}$, intermediate groundwater: ${\delta}^{18}O=-8.9\%_{\circ},\;{\delta}D=-59.6\%_{\circ}$, shallow groungwater : ${\delta}^{18}O=-8.0\%_{\circ},\;{\delta}D=-53.6\%_{\circ}$, surface water : ${\delta}^{18}O=-7.9\%_{\circ},\;{\delta}D=-53.3\%_{\circ}$ respectively.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.233-242
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• 2018

To overcome the low mechanical strength and corrosion behavior of a carbon steel canister at high temperature condition of a deep borehole, SiC ceramics were studied as an alternative material for the disposal canister. In this paper, a design concept for a SiC canister, along with an outer stainless steel container, was proposed, and its manufacturing feasibility was tested by fabricating several 1/3 scale canisters. The proposed canister can contain one PWR assembly. The outer container was also prepared for the string formation of SiC canisters. Thermal conductivity was measured for the SiC canister. The canister had a good thermal conductivity of above $70W{\cdot}m^{-1}{\cdot}K^{-1}$ at $100^{\circ}C$. The structural stability was checked under KURT environment, and it was found that the SiC ceramics did not exhibit any change for the 3 year corrosion test at $70^{\circ}C$. Therefore, it was concluded that SiC ceramics could be a good alternative to carbon steel in application to deep borehole disposal canisters.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.435-450
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• 2022

In step-by-step site selection for geological disposal of high-level radioactive waste, parameters necessary for site selection will be acquired through deep drilling surveys from the basic survey stage. Unlike site investigations of rock mass structures such as tunnels and underground oil storage facilities, those related to the geological disposal of high-level radioactive waste are not only conducted in relatively deep depths, but also require a high level of quality control. In this report, based on the 750 m depth drilling experience conducted to acquire the parameters necessary for deep geological disposal, the methodology for deep drilling and the geology, geophysics, geochemistry, hydrogeology and rock mechanics obtained before, during, and after deep drilling are discussed. The procedures for multidisciplinary geoscientific investigations were briefly described. Regarding in-situ stress, one of the key evaluation parameter in the field of rock engineering, foreign and domestic cases related to the geological disposal of high-level radioactive waste were presented, and variations with depth were presented, and matters to be considered or agonized in acquiring evaluation parameters were mentioned.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.114-118
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• 1998

농촌지역인 공주시 유구읍 명곡리 지역의 천부지하수와 먹는 샘물 공장의 취수정 심부 지하수을 대상으로 지화학적 특성을 밝히고, 물-암석 상호반응과 오염물질 유입에 대해서 토의하였다. 천부 지하수의 화학적 유형은 Ca-HCO$_3$형에서 Ca-Cl(SO$_4$)형으로 전반적으로 약산성화 되어있고, $K^{＋}$, Cl$^{-}$, NO$_3$$^{-}$오염이 상당히 진행되어 70 %이상이 음용수로 불가능한 상태이다. 군집방법에 의하면 신선한 물과 오염된 물사이에 뚜렷한 경향의 차이를 보인다. 천부지하수의 주요 오염원은 각가정에 있는 재래식 화장식, 생활하수, 가축의 축사, 비료등으로 보인다. 심부지하수는 알카리성의 Na-HCO$_3$형에서 Na(Ca)-HCO$_3$형의 화학적 유형이며, 2 TU 이하의 삼중수소 함량으로 1950년대 이전에 함양된 비교적 오랜 물-암석 상호반을 거친 물로 판단된다. 반면 천부형 지하수는 1950년대 이후에 충전된 상당히 젊은 연령의 지하수로 보인다. $^{18}$ O/$^{16}$ O, D/H 환경동위원소 조성값으로 볼 때 심부지하수의 함양지역은 고도의 효과를 보인다. 이 연구결과는 농촌지역의 지하수 수질 오염에 대한 하나의 사례연구로 향후 전국을 대상으로 한 농어촌지역의 지하수 오염연구에 기본방향을 제시하는데 의의 가 있을 것이다.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2002.10a
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• pp.69-92
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• 2002

비금속 및 금속 광물자원의 탐사는 국가경영에 있어서 절대적으로 필요한 공공의 기반산업에 해당된다. 지금까지 수행되어 왔던 자원 탐사사업의 대부분은 비교적 개발이 용이한 천부 광상들에 집중되어 왔으며, 천부 광상들의 과도한 개발로 인하여 자원탐사의 범위가 점차 심부화 되고있는 실정이다. 지하 심부에 분포하는 광상들을 효율적으로 탐사해 내기 위해서는 분지 내 심부 퇴적층들에 대한 정밀한 대비와 평가가 요구된다. 그러나, 그 동안 천부 광상들의 평가에 적용되어 왔던 기재적 층서 원리들로는 심부에 분포하는 광상들을 도출해 내는데 한계가 있어 왔다. 따라서, 분지 내 퇴적층들에 대한 보다 명확한 이해를 위해 새로운 고해상도의 층서틀 수립이 시급하다. 본 연구에서는 태백산분지 오오도비스 중기 퇴적층들에 대한 통합 층서적 접근을 통하여 고해상도 층서틀 수립에 대한 예를 제시하고자 한다. 이러한 통합 층서적 접근은 퇴적 분지의 지체 구조적 진화에 따른 층서를 규명하는데 있어서 보다 나은 통찰을 제공하고 있으며, 아울러 분지 내 비금속 및 금속 광물자원 탐사 및 개발사업의 효율성을 증대시키는데 사용될 수 있을 것이다 따라서, 통합 층서적 접근을 통한 퇴적층들에 대한 고해상도 층서틀 수립은 분지 내에 부존 되어 있는 모든 형태의 자원 탐사 및 개발사업에 있어서 성공률을 극대화시킬 수 있는 새로운 층서적 규범으로 강조되어 져야 한다.

• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.308-311
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• 2013

Deep sylvian meningioma is a rare form of meningiomas. So far, only 4 cases including the present one have been reported in South Korea. A 43-year-old man without any previous medical history presented to our hospital with seizure. There was a rim enhancing mass in the right deep sylvian fissure without dural attachment on magnetic resonance images. Surgical resection of the mass revealed the lesion to be a meningioma in this patient.