• 방사성폐기물학회지
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• 제9권1호
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• pp.41-48
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• 2011

한국원자력연구원 내 지하 처분 연구시설(KURT)에서 채취한 지하수에 존재하는 나노 콜로이드 입자의 크기 및 농도를 현상에서 조사하기 위해 이동식 레이저 유도 파열 검출 장치를 개발하였다. 제작한 장치는 CCD 카메라를 이용하여 레이저 유도 플라즈마가 발생한 위치를 2-차원 영상으로 기록함으로써 광학적으로 입자의 크기를 결정할 수 있다. 크기가 정확히 알려진 폴리스틸렌 표준 입자를 이용하여 입자 크기 측정용 검정 곡선 (calibration curve)을 구했고, 이를 이용하여 지하 처분 연구시설에서 채취한 지하수 내 콜로이드 입자의 크기를 측정하였다. 지하수 내 존재하는 콜로이드 입자의 평균 크기는 $108{\pm}26$ nm 임을 보였고, 농도는 50 ppb 이하인 것으로 추정하였다.

• 한국산학기술학회논문지
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• 제15권3호
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• pp.1259-1264
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• 2014

수소는 미래 에너지원 중 하나로서, 이미 여러 산업분야와 항공우주 분야에서 널리 사용되고 있다. 수소는 작은 분자크기로 인해 수송관이나 저장탱크의 작은 금으로부터 쉽게 가스 누설이 일어난다. 본 연구에서는 소량의 수소 누설을 측정하기 위한 탐지 기술을 개발하기 위하여 레이저 유도 플라스마 분광법을 이용하였다. Al, Cu, SUS등 세 가지의 금속을 가지고, 각 금속이 플라스마 발생 및 signal에 미치는 영향과 반복적인 레이저 조사로 인한 표면의 손상을 표면전자현미경(SEM)으로 관찰하고, 표면 손상이 signal에 미치는 영향을 조사하였다. 연구결과 Al을 이용한 경우 signal의 세기가 다른 두 금속에 비해 좋으며, 표면 손상으로 인한 signal의 영향 또한 다른 금속에 비해 Al을 사용 시 원자광의 변화가 약 $100W/m^2$ 적은 것으로 관찰되었다.

• 조명전기설비학회논문지
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• 제24권5호
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• pp.160-168
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• 2010

본 논문은 대기압 펄스 배리어 방전을 이용하여 NO 가스를 무해한 물질로 환원시키기 위하여 방전공간에서의 NO 분자의 생성 및 제거과정에 대하여 레이져 유기형광법을 이용하여 시 공간적인 밀도변화를 측정 및 분석하였다. 사용된 펄스 배리어 방전리액터는 진전속도가 $2.7{\times}10^6$[m/s] 인 1차 스트리머가 음극표면에 도착한 이후에 2차 스트리머가 양극 부근에 발생되었다. 그리고, 펄스 레이져에 의하여 NO 분자만을 효율적으로 상위준위로 여기시키기 위하여 Nd:Yag 및 염료 레이져를 복합하여 226[nm]의 자외광을 방전공간으로 도입하였으며, NO 분자만을 $A^2{\Sigma}^+{\leftarrow}X^2{\prod}$(0,0)으로 여기시키고, 여기된 분자들이 낮은 준위 $A^2{\Sigma}^+{\rightarrow}X^2{\prod}$(0,2), (0,3)로 복귀됨에 따라 방출되는 주요한 형광신호를 측정하였다. NO 분자의 시 공간적 변화 측정결과로부터 NO 가스를 효율적으로 제거하기 위해서는 산소농도를 가능한 2 [%]이하로 낮추고, 2차 스트리머 진전에 의해서 충분하게 방전공간에서 NO 환원반응을 유발할 수 있도록 제어하는 것이 필요하다고 판단된다.

• International journal of advanced smart convergence
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• 제6권4호
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• pp.88-95
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• 2017

The conventional scan methods are based on a laser scanner and a depth camera, which requires high cost and complicated post-processing. Whereas in photometric scanning method, the 3D modeling data is acquired through multi-view images. This is advantageous compared to the other methods. The quality of a photometric 3D model depends on the environmental conditions or the object characteristics, but the quality is lower as compared to other methods. Therefore, various methods for improving the quality of photometric scanning are being studied. In this paper, we aim to investigate the effect of illumination conditions on the quality of photometric scanning data. To do this, 'Moai' statue is 3D printed with a size of $600(H){\times}1,000(V){\times}600(D)$. The printed object is photographed under the hard light and soft light environments. We obtained the modeling data by photometric scanning method and compared it with the ground truth of 'Moai'. The 'Point-to-Point' method used to analyseanalyze the modeling data using open source tool 'CloudCompare'. As a result of comparison, it is confirmed that the standard deviation value of the 3D model generated under the soft light is 0.090686 and the standard deviation value of the 3D model generated under the hard light is 0.039954. This proves that the higher quality 3D modeling data can be obtained in a hard light environment. The results of this paper are expected to be applied for the acquisition of high-quality data.

• Journal of Pharmaceutical Investigation
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• 제28권3호
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• pp.171-175
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• 1998

KHPC-002 $[(trans-l-diaminocyclohexane-bis-l,2(diphenylphosphinoethane)platinum)\;{\cdot}2NO_3]$ and $KHPC-006[(cis-diaminocyclohexane-bis-1,2(diphenylphosphinoethane)platinum)\;{\cdot}2NO_3]$ were synthesized as candidates for third platinum antitumor agent. Before their pharmacokinetic study, we optimized the analytical condition with HPLC and identified the major metabolites in the rat plasma. HPLC analysis by $C_{18}$ reverse-phase column showed that standard peak of both compounds appeared rapidly at around 1 minutes, whereas metabolites of KHPC-002 and KHPC-006 which were extracted from plasma after single I.V. administration in rats or incubation for 24 hr at $37^{\circ}C$ showed retention time of $10{\sim}11$ minutes. These metabolites were identified as the major compound by Matrix Associated Laser Deposition/Ionization (MALDI), which only lose the 2 molecules of $NO_3$. Based on these results, we suggest that the major metabolites of KHPC-002 and KHPC-006 were [trans-l-diamino-cyclohexane-bis-l,2(diphenylphosphinoethane)platinum] and [cis-diaminocyclohexane-bis-l.2(diphenylphosphinoethane)platinum], respectively.

• The Journal of Advanced Prosthodontics
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• 제2권1호
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• pp.7-13
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• 2010

Although most researchers agree that platelet-rich plasma (PRP) is a good source of autogenous growth factors, its effect on bone regeneration is still controversial. The purpose of this study was to evaluate whether increasing angiogenic factors in the human PRP to enhance new bone formation through rapid angiogenesis. MATERIAL AND METHODS. In vitro, the human platelets were activated with application of shear stress, $20\;{\mu}g/ml$ collagen, 2 mM $CaCl_2$ and 10U thrombin/$1\;{\times}\;10^9$ platelets. Level of vascular endothelial growth factor (VEGF) and platelet microparticle (PMP) in the activated platelets were checked. In the animal study, human angiogenic factors-enriched PRP was tested in 28 athymic rat's cranial critical bone defects with $\beta$-TCP. Angiogenesis and osteogenesis were evaluated by laser Doppler perfusion imaging, histology, dual energy X-ray densinometry, and micro-computed tomography. RESULTS. In vitro, this human angiogenic factors-enriched PRP resulted in better cellular proliferation and osteogenic differentiation. In vivo, increasing angiogenic potential of the PRP showed significantly higher blood perfusion around the defect and enhanced new bone formation around acellular bone graft material. CONCLUSION. Angiogenic factor-enriched PRP leads to faster and more extensive new bone formation in the critical size bone defect. The results implicate that rapid angiogenesis in the initial healing period by PRP could be supposed as a way to overcome short term effect of the rapid angiogenesis.

• 한국표면공학회지
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• 제56권3호
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• pp.208-218
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• 2023

Photocatalysts are advanced materials which accelerate the photoreaction by providing ordinary reactions with other pathways. The catalysts have various advantages, such as low-cost, low operating temperature and pressure, and long-term use. They are applied to environmental and energy field, including the air and water purification, water splitting for hydrogen production, sterilization and self-cleaning surfaces. However, commercial photocatalysts only absorb ultraviolet light between 100 and 400 nm of wavelength which comprises only 5% in sunlight due to the wide band gap. In addition, rapid recombination of electron-hole pairs reduces the photocatalytic performance. Recently, studies on blackening photocatalysts by laser, thermal, and plasma treatments have been conducted to enhance the absorption of visible light and photocatalytic activity. The disordered structures could yield mid-gap states and vacancies could cause charge carrier trapping. Herein, liquid phase plasma (LPP) is adopted to synthesize Ag-doped black ZnO for the utilization of visible-light. The physical and chemical characteristics of the synthesized photocatalysts are analyzed by SEM/EDS, XRD, XPS and the optical properties of them are investigated using UV/Vis DRS and PL analyses. Lastly, the photocatalytic activity was evaluated using methylene blue as a pollutant.

• 한국발생생물학회지:발생과생식
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• 제14권2호
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• pp.99-105
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• 2010

정세관은 매우 복잡한 조직으로 마우스의 정자 발생 과정은 12단계로 구성되어 있다. Glutathione peroxidase(GPx)는 glutathione을 이용하여 과산화물(hydroperoxide)을 환원시키는 대표적인 항산화효소로서 포유류 정자 발생 과정에 관여하는 것으로 알려져 있다. 본 연구에서는 laser capture microdissection(LCM)을 이용하여 마우스 정소에서 발생 단계별로 정세관을 채취하여 real-time PCR로 cytosolic GPx(cGPx), gastrointestinal GPx(GI-GPx), plasma GPx(pGPx) 및 phospholipid hydroperoxide GPx(PHGPx)와 같은 GPx family 유전자의 발현 정도를 비교분석하였다. 동결절편(10 ${\mu}m$)은 정상 성숙 마우스의 정소를 사용하였다. LCM 방법으로 정세관의 단면을 I~V, VII~VIII, IX~XI 단계로 구별하여 채취하였다. PHGPx mRNA의 발현은 다른 GPx mRNA보다 정소에서 현저하게 높게 발현되었다. 정자 발생 단계에서 GI-GPx, pGPx 및 PHGPx의 mRNA는 VII~VIII 단계에서 가장 높았고 XI 단계 이후에 감소되었으며, I~V 단계에서 가장 낮은 발현을 보였다. 그러나, cGPx mRNA는 VII~VIII 단계에서 가장 높았고, XI~XI 단계에서 가장 낮은 발현을 보였다. 본 연구 결과, GPx family 유전자는 정자 발생 단계에서 서로 다르게 조절되며, LCM 방법은 정소세포의 정량 분석에서 유용하게 사용될 것으로 사료된다.

• Journal of Welding and Joining
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• 제24권6호
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• pp.33-38
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• 2006

Since the 1990's, European shipbuilding industries introduced hybrid welding process in order to decrease thermal distortion of welded joints in passenger shipbuilding. In this study, we investigated effects of hybrid welding parameters on the toughness of weld metal using DH36 steel in order to obtain more sound welds in passenger shipbuilding. Type of leading process, joint gap distance and chemical composition of consumables were considerably correlated with the toughness of weld metal. Especially, the toughness was considerably increased with high-Ti containing consumables. In addition, hybrid welding speed increased by using plasma cut edges, the oxides layer of which increased absorption efficiency of laser beam.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.18-21
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• 2000

A nonconstact technique for reducing the core loss of a grain oriented silicon steel has been developed by the use of mechanical scribing Q-switched laser plasma jet or electron beam irradiation. Among these methods electron beam irradiation has advantages of domain refining without any deformation or damage of insulating film on the surface of a grain criented Si-Fe. Over the past years this processing was performed in vaccum of 10-4 Torr or below causing the problem of high cost and difficulty of continuous works. In this paper a miniature electron permeable window through which electron beam energy 4-80keV and average current 0.1-2mA. were obtained for electron beam irradiating on air was designed and manufactured.