• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.87-92
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• 2005

Experiments at the Japan Microgravity Center(JAMIC) have investigated the interaction between diffusion flames and solid surfaces placed near flames. The fuel for the flames was $C_2H_4$. The surrounding oxygen concentration was 35% with temperatures of $T_a$=300. Especially, the effect of wall temperature on soot deposition from a diffusion flame placed near the wall has been studied by utilizing microgravity environment, which can attain very stable flame along the wall. Cylindrical burner with fuel injection was adopted to obtain two dimensional soot distributions by laser extinction method. In the experiment two different wall temperatures, $T_w$=300,800K, were selected as test conditions. The results showed that the soot distribution between flame and burner wall was strongly affected by the wall temperature and soot deposition increases with decrease in wall temperature. The comparison among the values for two different wall temperatures suggested that the change in thermophoretic effect is the most dominant factor to give the change in soot deposition characteristics.

• Journal of Gastric Cancer
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• 제11권4호
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• pp.230-233
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• 2011

Regarding the removal of a gastric bezoar, laparoscopic surgery was performed and it was shown that the laparoscopic approach is safe and feasible. However, the laparoscopic method has the risk of intraabdominal contamination, when the gastric bezoar is retrieved from the gastric lumen in the peritoneal cavity. We developed and applied a new procedure for the removal of the gastric bezoar using one surgical glove and two wound retractors as a fashion of intragastric single port surgery. Herein we present this new minimal invasive procedure, so named "hybrid access surgery" which involves the use of existing devices and overcomes the weakness of laparoscopic removal of the gastric bezoar. Our new procedure, combining the concept of intragastric and single port access, is acceptable and feasible to retrieve the gastric bezoar. In the future, this procedure may be one of the alternative procedures for retrieving gastric bezoar even when it is incarcerated in the pylorus.

• 대한조선학회논문집
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• 제35권4호
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• pp.55-64
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• 1998

본 연구에서는 구멍뚫기 기법을 사용하여 여러 입열량과 두께대 직경을 가진 원통에서 원주용접에 의해 발생되는 잔류응력과 용접변형을 측정하였다. 그 결과, 입열량과 원통 두께대 직경이 커짐에 따라 축 및 원주 잔류응력은 커지게 됨을 확인하였으며 이것은 Fujita 등의 결과와 잘 일치하였다. 원통 원주용접 시의 지배 파라메터인 입열량과 두께 대 직경비는 축 및 원주방향의 잔류응력과 용접변형의 분포 및 크기에 영향을 미치고 있음을 확인하였으며, 다중회귀분석법을 적용하여 실험결과의 범위내에 있는 원주용접된 원통에 대한 잔류응력과 용접변형을 예측할 수 있는 근사식을 도출하였다.

• 대한방사선기술학회지:방사선기술과학
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• 제43권4호
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• pp.251-257
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• 2020

This study was purpose to quantitative evaluation of edge method of modulation transfer function(MTF) and physical image characteristics of by obtain the optimal edge image by using magnetic resonance imaging(MRI). The MRI equipment was used (MAGNETOM Vida 3.0T MRI, Siemense healthcare system, Germany) and the head/neck matrix shim MR coil were 20 channels(elements) receive coil. The MTF results of showed the best value of 0.294 based on the T2 Nyquist frequency of 1.0 mm^-1. The MTF results of showed that the T1 image is 0.160, the T1 CE image is 0.250, T1 Conca2 image is 0.043, and the T1 CE (Concatenation) Conca2 image is 0.190. The T2 image highest quantitatively value for MTF. The physical image characteristics of this study were to that can be used efficiently of the MRI and to present the quantitative evaluation method and physical image characteristics of 3.0T MRI.

• 대한방사선기술학회지:방사선기술과학
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• 제45권1호
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• pp.11-17
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• 2022

This study was purpose to quantitative assessment of the resolution characteristics by using American college of radiology(ACR) phantom for magnetic resonance imaging (MRI). The MRI equipment was used (Achiva 3.0T MRI, Philips system, Netherlands) and the head/neck matrix shim SENSE head coil were 32 channels(elements) receive MR coil. And the MRI equipment was used (Discovery MR 750, 3.0T MRI, GE medical system, America) and the head/neck matrix shim MC 3003G-32R 32-CH head coil were receive MR coil. As for the modulation transfer function(MTF) comparison result by using ACR magnetic resonance imaging phantom, the MTF value of the ACR standard T2 image in GE equipment is 0.199 when the frequency is 1.0 mm^-1 and the MTF value of the hospital T2 image in Philips equipment is 0.528. It was used efficiently by using a general sequence more than the standard sequence method using the ACR phantom. In addition it is significant that the quantitative quality assurance evaluation method for resolution characteristics was applied mutatis mutandis, and the result values of the physical image characteristics of the 3.0T MRI device were presented.

• Journal of Photoscience
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• 제9권2호
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• pp.451-453
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• 2002

A new concept of "photo" -antisense method has been evaluated, where the inhibition of gene expression by the conventional antisense method is enhanced by photochemical binding between antisense oligonucleotides conjugated with photo-reactive compound and target mRNA or DNA. Fluorescein labeled oligodeoxyribonucleotides (F-DNA) was delivered to cell nuclei in the encapsulated form in multilamellar lecithin liposomes with neutral charge. F-DNA was previously shown to photo-bind to the complementary stranded DNA, and the delivery system using neutral liposome to be effective in normal human keratinocytes. In the present study, we used human kidney cancer G401.2/6TG.1 cell line to be advantageous in reproducible experiments. p53 was adopted as a target gene since antisense sequence information has been accumulated. The nuclear localization ofF-DNA was identified by comparing the fluorescence ofF-DNA with that of Hoechst 33258 under fluorescence microscope. After 7hr incubation to accumulate p53 protein induced by UV -B, p53 protein was quantified by Western blot. After 2hrs from F-DNA application, about 30% of cell population incorporated F-DNA in their nuclei with some morphological change possibly due to liposomal toxicity. Irradiation of visible light longer than 400nm from solar simulator at this time enhanced the inhibitory action of antisense F-DNA. The present results suggest that photo-antisense method is promising to control gene expression in time and space dependent manner. Further improvement of F-DNA delivery to cancer cells in the stability and toxicity is in progress. progress.

• 대한방사선기술학회지:방사선기술과학
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• 제29권3호
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• pp.133-139
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• 2006

디지털 X선영상으로 출력한 화상데이터를 Personal Computer로 가져와서 디지털 특성곡선, MTF, 위너스펙트럼을 계산할 수가 있다. 여기서는 디지털화상의 선예도를 후지타(藤田) 등의 이론에 의한 프리샘플링(presampling) Modualtion Transfer Function(MTF)을 산출하고 보정하는 방법에 대하여 검토하였다. 사용한 프로그램은 엑셀이며 슬릿의 촬영, 디지털 특성곡선, 합성 LSF법, 이산 퓨리어 변환, 고속 퓨리어 변환 등의 순서로 기술하였다. 이 방법의 커다란 장점은 퓨리어트랜스폼의 공식과 MTF 산출과정을 완전히 이해할 수 있다는 점과, 별도로 값비싼 프로그램이나 컴퓨터언어를 배우지 않았어도 MTF 결과를 산출할 수가 있다는 것이다. 그리고 워크시트 표시되는 엑셀의 장점을 그대로 살려 X선 영상계의 오류나 산출결과의 부적합성을 발견하기 쉽다는 점이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1761-1763
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• 1997

Because of internal voids in insulators give rise to partial discharge (PD), which cause local breakdown and even entire insulation breakdown. Treeing due to PD is one of the main causes of breakdown of the insulating materials and reduction of the insulation life. Therefore the necessity for establishing a method to diagnose the aging of insulation materials and to predict the breakdown of insulation has become important. From this viewpoint, our studies diagnose insulation degradation using the method of computer sensing system, which has the advantages of PD and acoustic emission (AE) sensing system. To use advantages of these two methods can be used effectively to search for treeing location and PD in some materials. In analysis method of degradation, We analyzed the PD pulse and AE pulses by regression analysis, compared to these obtained the correlation coefficient and determination coefficient by T-distribution and saw that PD and AE pulses show a similar pattern on the whole. This is in agreement with the results of the research by Yoshimura and Fujita.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.60-60
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• 2015

Nanosheets of graphene and related 2D materials have attracted much attention due to excellent physical, chemical and mechanical properties. Single-layer graphene (SLG) was first synthesized by Blakely et al in 1974 [1]. Following his achievements, we initiated the growth and characterization of graphene and h-BN on metal substrates using surface segregation and precipitation in 1980s [2,3]. There are three important steps for nanosheet growth; surface segregation of dopants, surface reaction for monolayer phase, and subsequent 3-D growth (surface precipitation). Surface phase transition was clearly demonstrated on C-doped Ni(111) by in situ XPS at elevated temperatures [4]. The growth mode was clarified by inelastic background analysis [5]. The surface segregation approach has been applied to C-doped Pt(111) and Pd(111), and controllable growth of SLG has been demonstrated successfully [6]. Recently we proposed a promising method for producing SLG fully covering an entire substrate using Ni films deposited on graphite substrates [7]. A universal method for layer counting has been proposed [8]. In this paper, we will focus on the effect of competitive surface-site occupation between carbon and other surface-active impurities on the graphene growth. It is known that S is a typical impurity of metals and the most surface-active element. The surface sites shall be occupied by S through surface segregation. In the case of Ni(110), it is confirmed by AES and STM that the available surface sites is nearly occupied by S with a centered $2{\times}2$ arrangement. When Ni(110) is doped with C, surface segregation of C may be interfered by surface active elements like S. In this case, nanoscopic characterization has discovered a preferred directional growth of SLG, exhibiting a square-like shape (Fig. 1). Also the detailed characterization methodologies for graphene and h-BN nanosheets, including AFM, STM, KPFM, AES, HIM and XPS shall be discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.561-565
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• 1994

An automatic measuring system of three dimensional shape by a projection method with grating pattern from in optical spatial modulator has been developed. The characteristics of the system were studied. This system is composed of a projector, an optical spatial modulator, a CCD camera, and computer. A liquid crystal is used as the optical spatial modulator. The grating patterns that ire projected on the surface of the object are controlled by the computer connected with the optical spatial modulator. The projector patterns are measured by the CCD camera. The data are transferred to the computer. After a transformation into line data, the data are analyzed to obtain the coordinate of the surface of the object. This system has advantages as follows. (1) It is possible to capture the surface topography without any contact. (2) The time required for the measurements is shorter than the light-section method. (3) An optical spatial modulator using a liquid crystal is possible to control the grating patterns accurately by a computer. Surfaces of a plate and a cylinder were measured. The threshold level had an influence on the measurement. It was shown that this system has adequae accuracy in the measurements.