• 방사선산업학회지
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• 제4권1호
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• pp.7-11
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• 2010

Clotrimazole [1-{(2-chlorophenyl)-diphenylmethyl}-1H-imidazole, CLT] has been reported to inhibit the proliferation of vascular endothelial and act as an in vitro anti-VEGF drug. It is also shown to inhibit angiogenesis in an animal model. The radioisotope labeled clotrimazole derivative can be utilized to monitor the physiologic processes of cancer. In this study, we synthesized [$^{18}F$]fluoride labeled clotrimazole derivatives as a new tumor imaging agent for PET. The references were prepared by a refluxing with clotrimazole and an excess of fluoroalkyltosylate in acetonitrile for 36 h and clotrimazole reacted with ditosylalkane to give precursors. [$^{18}F$]Fluoride labeled reaction was performed with precursor in Kryptofix[2.2.2]/$K_2CO_3$ for 10 min at $80^{\circ}C$. The radiolabeling mixture was passed through a silica Sep-Pak cartridge to remove $^{18}F^-$. The [$^{18}F$]F-clotrimazole derivatives were synthesized with a 20~25% yield. In the radiofluorination step, we used acetonitrile and DMSO as a solvent and observed a higher yield at the acetonitrile (25%) reaction compared with the DMSO reaction (5%).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.112-112
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• 2013

Well-defined surfaces of single-crystalline solid materials are starting points of self-organizationof nanostructures and chemical reactions controlled in nanoscale. Although highly ordered atomicarrangement can be obtained on semiconductor surfaces, they can be maintained only in vacuumand not in air or in aqueous environment. Since single-crystalline metal oxide surfaces arechemically stable and no further oxidation occurs, their atomic structures can be utilized fornanofabrication in liquid processes, nanoelectrochemistry and nanobiotechnology. Sapphire is oneof the most stable metal oxides and its crystalline quality is excellent, as can be applied to electronicdevices that require ultralow defect densities. We recently found that chemical phase separationoccurs on sapphire surfaces by annealing processes and the formed nanodomains exhibit specificproperties in air and in water [1,2]. In our experiments, highly selective and controllable adsorptionof various protein molecules is observed on the phase-separated surfaces though the materials andcrystallographic orientations are identical [3,4]. Planar lipid bilayers supported on thephase-separated sapphire surface also exhibit a specific formation site selectivity [5]. Chemicalnanodomains appear on other metal-oxide surfaces, such as well-ordered titania surfaces. Wedemonstrate that surface chemistry of the nanodomains can be characterized in aqueousenvironment using atomic force microscopy equipped with colloidal tips and then show adsorptionand desorption behaviors of various proteins on the phase-separated surfaces.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.395-400
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• 2005

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin damaged layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip. The damaged layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the novel fabrication processes of the micro cantilever and diamond tip as a tool for TNL using micro-patterning, wet chemical etching and CVD. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

• 한국정밀공학회지
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• 제23권8호
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• pp.39-46
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• 2006

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin mask layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip. The mask layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the novel fabrication processes of the micro cantilever and diamond tip as a tool for TNL using micro-patterning, wet chemical etching and CVD. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.849-858
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• 2015

This study set the pyroprocess facility at an engineering scale as a cost object, and presented the cost consumed during the unit processes of the pyroprocess. For the cost calculation, the activity based costing (ABC) method was used instead of the engineering cost estimation method, which calculates the cost based on the conceptual design of the pyroprocess facility. The calculation results demonstrate that the pyroprocess facility's unit process cost is $194/kgHM for pretreatment, $298/kgHM for electrochemical reduction, $226/kgHM for electrorefining, and $299/kgHM for electrowinning. An analysis demonstrated that the share of each unit process cost among the total pyroprocess cost is as follows: 19% for pretreatment, 29% for electrochemical reduction, 22% for electrorefining, and 30% for electrowinning. The total unit cost of the pyroprocess was calculated at $1,017/kgHM. In the end, electrochemical reduction and the electrowinning process took up most of the cost, and the individual costs for these two processes was found to be similar. This is because significant raw material cost is required for the electrochemical reduction process, which uses platinum as an anode electrode. In addition, significant raw material costs are required, such as for $Li_3PO_4$, which is used a lot during the salt purification process.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.401-406
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• 2018

We investigated the effect of ZnO seed layer thickness on the density of ZnO nanorod arrays. ZnO has been deposited using two distinct processes consisting of the seed layer deposition using ALD and subsequent hydrothermal ZnO growth. Due to the coexistence of the growth and dissociation during ZnO hydrothermal growth process on the seed layer, the thickness of seed layer plays a critical role in determining the nanorod growth and morphology. The optimized thickness resulted in the regular ZnO nanorod growth. Moreover, the introduction of ALD to form the seed layer facilitates the growth of the nanorods on ultrathin seed layer and enables the densification of nanorods with a narrow change in the seed layer thickness. This study demonstrates that ALD technique can produce densely packed, virtually defect-free, and highly uniform seed layers and two distinctive processes may form ZnO as the final product via the initial nucleation step consisting of the reaction between $Zn^{2+}$ ions from respective zinc precursors and $OH^-$ ions from $H_2O$.

• 터널과지하공간
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• 제31권4호
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• pp.221-242
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• 2021

기존의 한국형 기준 처분시스템의 처분 효율을 높인 향상된 한국형 기준 처분시스템(Improved Korean Reference Disposal System, KRS⁺)의 열-수리-역학적 복합거동 성능평가를 위해 TOUGH2-MP/FLAC3D를 이용한 수치모델링 연구가 수행되었다. 사용후핵연료 처분 이후 방사성 붕괴열에 의해 처분시스템의 온도가 상승하고, 방사성 붕괴열이 빠르게 감소함에 따라 온도가 감소하여 최대 온도가 설계기준 온도인 100℃를 넘지 않는 것으로 나타났다. 완충재의 초기 포화도는 온도 상승으로 인한 공극수의 증발로 인해 감소하였다가 주변 암반으로부터 지하수가 유입되어 처분 약 250년 후 포화 상태에 이르렀다. 암반에서는 완충재와 암반의 흡입력의 차이로 인해 암반에서 완충재로 지하수가 유입되어 처분 직후 포화도가 감소하다가 이후 원계 암반으로부터 지하수가 유입되어 포화 상태에 도달했다. 처분시스템 내 열응력과 팽윤압 발생에 의한 주변 암반의 파괴 가능성을 평가하고자 모어-쿨롱 파괴기준식과 스폴링 강도를 사용하였다. KRS⁺ 처분시스템의 처분공의 간격을 감소시키면서 처분시스템의 열적 거동 변화를 확인하였는데, 처분공 간격이 5.5 m 이하에서는 완충재의 설계 기준 온도를 초과하게 된다. 다만, 벤토나이트 완충재 부피의 56.1%의 온도는 90℃ 이하로 유지되었다. 본 연구에서 사용한 수치해석 기법은 향후 응력 모델, 지온 경사 및 입력 물성을 변화시킨 다양한 조건에서의 처분시스템의 THM 복합거동 성능평가에 활용할 수 있을 것으로 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1520-1524
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• 2004

This paper describes the development of a robotic maintenance system for use in a maintenance operation of the nozzle dam in a water chamber of a steam generator at the Kori nuclear power plant in Korea. The robotic maintenance system was designed to minimize the personnel exposure to a hazardous radioactive environment. This robotic maintenance system is operated by a teleoperated control which was designed to perform the nozzle dam maintenance tasks in a remote manner without endangering the human workers. Specific maintenance tasks involve the transportation, insertion, and removal of nozzle dams in a water chamber inside a steam generator via a narrow man-way entrance port. The developed robotic maintenance system has two major subsystems: a two degrees of freedom guiding device acting as the main guiding arm and a master-slave manipulator with a kinematic dissimilarity. The mechanical design considerations, control system, and capabilities of the robotic maintenance system are presented. Finally, a graphical representation of the nozzle dam maintenance processes in a simulated work environment are also demonstrated.

• Preventive Nutrition and Food Science
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• 제22권3호
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• pp.216-222
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• 2017

Antioxidant rich green leafy vegetables including garden spinach leaf, water spinach leaf, Indian spinach leaf, and green leaved amaranth were selected to evaluate the effects of water boiling and oil frying on their total phenolic content (TPC), total flavonoid content (TFC), reducing power (RP), and antioxidant capacity. The results revealed that there was a significant increase in TPC, TFC, and RP in all the selected vegetables indicating the effectiveness of the cooking process on the antioxidant potential of leafy vegetables. Both cooking processes enhanced significantly (P<0.05) the radical scavenging ability, especially the oil fried samples showed the highest values. There is a significant reduction in the vitamin C content in all the vegetables due to boiling and frying except in the Indian spinach leaf. However, the present findings suggest that boiling and frying can be used to enhance the antioxidant ability, by increasing the bioaccessibility of health-promoting constituents from the four vegetables investigated in this study.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.90-102
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• 2015

To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO₃ type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.