• 한국의학물리학회지:의학물리
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• 제28권3호
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• pp.83-91
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• 2017

In this work, we investigated the recently proposed phase-contrast x-ray imaging (PCXI) technique, the so-called single grid-based PCXI, which has great simplicity and minimal requirements on the setup alignment. It allows for imaging of smaller features and variations in the examined sample than conventional attenuation-based x-ray imaging with lower x-ray dose. We performed a systematic simulation using a simulation platform developed by us to investigate the image characteristics. We also performed a preliminary PCXI experiment using an established a table-top setup to demonstrate the performance of the simulation platform. The system consists of an x-ray tube ($50kV_p$, 5 mAs), a focused-linear grid (200-lines/inch), and a flat-panel detector ($48-{\mu}m$ pixel size). According to our results, the simulated contrast of phase images was much enhanced, compared to that of the absorption images. The scattering length scale estimated for a given simulation condition was about 117 nm. It was very similar, at least qualitatively, to the experimental contrast, which demonstrates the performance of the simulation platform. We also found that the level of the phase gradient of oriented structures strongly depended on the orientation of the structure relative to that of linear grids.

• 실천공학교육논문지
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• 제11권2호
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• pp.143-150
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• 2019

회로 이론은 전기 및 전자 공학 분야에서 가장 기본이 되는 다양한 회로의 해석과 설계를 체계화한 학문으로 회로 이론 교과목은 전기 및 전자 공학도라면 반드시 습득하도록 4년제 대학을 기준으로 학부 2학년에 한 학기 내지는 2 학기에 걸쳐 전공 교과목으로 편성되어 있다. 또한 학생들이 회로 이론에 대한 이해도를 높이고, 실제 회로를 구성한 실험을 통하여 회로 설계에 대한 기술 및 응용력을 습득할 수 있도록 하는 실험 교과목이 이론 교과목을 뒷받침하기 위해 동반 편성되고 있다. 본 논문에서는 회로 이론을 뒷받침하는 실험 교육에 대한 학습 효과를 높이기 위해 전기회로 설계 및 실험 교과목에서 시행하고 있는 수업 방법에 대한 사례 연구에 대해 기술한다. 이를 위해 이론 학습, 시뮬레이션, 실험 및 설계 프로젝트 등이 복합적으로 구성된 15주 수업 모형을 제안한다. 제시된 수업 모형에서는 이론을 보완하기 위한 시뮬레이션과 사전 실험 준비 과정이 강화되고, 공학 엔지니어로서의 실질적인 회로 설계 능력을 배양하기 위한 설계 프로젝트가 도입되어 운영된다. 5년 동안의 운영 결과는 제안된 모형이 효용성이 있음을 보여준다.

• 치과방사선
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• 제27권1호
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• pp.73-86
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• 1997

This study was performed to assess the analyzing methods developed to detect clinically and quantitatively longitudinal bone changes. Through preliminary experiment, accuracy of Cu-Eq value conversion to the mass of HA was examined. For main experiment, 15 intraoral radiograms taken at soon, 1st, 2nd, 4th, and 6th week after implantation of mixture in extracted sites of 3 cases were used. We took the radiograms with copper step wedge as test object and HA phantom X -ray taking was standardized by using Rinn XCP device customized directly to the individual dentition with resin bite block. The images inputted by Quick scanner into computer were digitized and analyzed by NIH image program. The stability of the copper equivalent transformation and the usefulness of two analyzing methods by ROI and Reslice were examined. Obtained results as follows: 1) On the Cu equivalent images, the coefficient of variation in the measurement of Cu-Eq. value of ROI ranged from 0.05 to 0.24 and showed high reproducibility. 2) All results obtained by resliced contiguous image were coincident with those obtained from the assessment by ROI and formation of plot profile. 3) On the stacked and resliced image at the line of interest, we could analyze directly and quantitatively the longitudinal changes at several portions by plot profile and qualitatively by surface plot. 4) Implant area showed marked resorption till 2 weeks after implantation and showed significant increase in Cu-Eq. value at 6th week(p<0.01) and periapical area showed increase in Cu-Eq. value at 6th week compared to after-operation's.

• Animal cells and systems
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• 제13권2호
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• pp.133-139
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• 2009

Green tea seed was extracted with absolute ethanol,and the green tea seed extract(GTSE)was subjected to assays for toxicity, antioxidant ability, angiogenesis inhibitory effects and cell adhesion, as well as western blotting, and an in vivo experiment against 4 high-ranking adult cancers in Korea. Our series of experimental data demonstrated that GTSE has an antioxidant ability superior to that of EGCG in the green tea leaf, and also exhibits a profound high tumor growth inhibitory activity on a variety of cancer cell lines, as well as nude mice infected with cancer cells. GTSE was identified as a natural anticancer compound showing excellent angiogenesis inhibition and cancer cell suppression abilities. Our preliminary observations also indicate that GTSE may be another potential source of natural dietary antioxidants and also may be applicable as a novel natural anticancer agent.

• 한국해양학회지:바다
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• 제4권3호
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• pp.161-169
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• 1999

해양음향 토모그래피에 의한 유속측정의 유효성을 검증하기 위하여 1997년 4월 거제도 남쪽해역에서 쌍방향 음파전파 토모그래피 실험을 실시하였다. 이 실험은 해양음향 토모그래피에 의한 실시간 유속관측 시스템을 구축하기 위한 현장 기초실험으로 시도되었다. 실험 당시의 해양물리 환경을 고려하면서 음파 전파시간 차이에 의한 유속측정 결과를 초음파 유속계(ADCP)에 의한 실측유속과 비교 분석하였다. 그 결과 두 실측치는 상관계수 0.943으로써 매우 양호한 상관관계를 보였으며, 해양음향 토모그래피에 의한 방법이 연안해역에서 유속측정 방법으로서 향후 크게 활용될 수 있으리라 판단된다.

• 한국강구조학회 논문집
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• 제13권1호
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• pp.1-8
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• 2001

본 연구는 콘크리트충전 각형강관을 이용한 기둥-H형 보 접합부에 있어서 시공성과 충전성을 고려하여 강관 기둥을 외부에서 보강한 충전 각형강관 기둥-H형강보접합부를 개발하고자 하며 이러한 접합방식 개발을 위한 기초적 연구로 보의 인장플랜지와 강관기둥 접합부의 인장거동을 실험적으로 관찰하여 제시한 접합부의 내력 및 변형 특성을 파악한다. 시험체의 변수는 각형강관 기둥의 보강 두께(T=9, 18, 27mm)와 높이(H=50, 80mm)로 계획하여 총 4개의 시험체를 제작하였다. 접합부의 항복내력의 평가로 항복선 이론을 적용한 기존의 연구를 수정하여 실험치와 비교한 결과 비교적 좋은 대응을 나타냈다. 본 연구의 접합방식은 외부에서 강관 기둥을 보강하는 간단한 방법으로 보붕괴형의 강접합을 얻을 수 있으며, 콘크리트 충전성을 확보할 수 있어 시공성에 있어서 장점으로 인정된다. 강관기둥의 두께가 8mm 인 것을 고려하면 실제 구조물의 설계에 적용할 수 있는 가능성이 있는 것으로 판단되며, 구체적인 설계방법을 위해서는 추치해석적인 방법에 의한 연구와 보완적인 실험이 필요한 것으로 생각된다.

• 한국해양환경ㆍ에너지학회지
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• 제9권3호
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• pp.141-147
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• 2006

해양의 활용범위를 확대시키기 위해서 방파제는 필수적인 요소이며 특히 친환경적인 부소파제의 활용은 증대될 것으로 기대된다. 본 연구에서는 친환경 소재인 폴리에틸렌 파이프와 시트를 활용하여 새로운 개념의 부소파제용 부체를 개발하며, 이에 대한 소파 성능평가를 위하여 기초적 실험연구를 수행한다. 입사되는 파랑은 연결된 파이프와 시트를 통과하면서 일부는 반사되고 일부는 투과되는데, 투과되는 파랑은 파이프를 지나면서 와류유기가 발생하여 파랑 에너지가 소멸된다. 따라서 입사파랑 에너지를 감소시킬 수 있다. 개발된 부체의 성능평가를 위하여 규칙파 및 붙규칙파에 대한 수리모형 실험을 수행한다. 입사파랑 주기가 6초 이하 조건에서는 소파 성능이 양호하였으나, 장주기의 입사파랑에 대해서는 부체 전체가 해수면과 같이 거동하면서 소파성능을 거의 나타내지 못하였다. 향후 소파성능 개선을 위한 추가적인 연구가 요구되어진다.

• 한국의류학회지
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• 제30권4호
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• pp.567-581
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• 2006

The purpose of this research is to provide the basic data for the development of make-up color application system, based of Korean's skin tone and the preference in make-up color to enhance the effectiveness of the education of beauty in universities. The research was conducted by the previous studies, the analyses of sale's rate of hue-cosmetics, the analytic experiment of color of cosmetics by using Spectrum Color Analyzer and other experimental researches. This research, based on the results of three preliminary researches, shows the result of evaluation from perceivers which has been come out from the experiment of having one model in her twenties being changed with twenty-two different conditions of make-up. Here follows the result of the research. Firstly, there was difference on perceiving images in terms of the gender of perceivers and especially male-group tend to have clearly perceived the gap between elegance-greyish purple, orange-natural, red-classic on monochrome make-up and contrast make-up. Secondly, in terms of lip-colors, salmon pink and pink was regarded positively to both female and male subjects and to male subjects, greyish purple was thought to be better on darker skin-tone and to female subjects, better on lighter skin-tone. Thirdly, on image make-up, romantic gives intelligent image regardless of skin-tone and gender, especially gives more positive looks to male subjects. Natural and classic elements were perceived more positively on darker skin-tone and had bigger perceiving gap in female subjects. Fourthly, in preference rate, male subjects normally preferred the look with make-up than female subjects did and salmon pink and pink lip color was preferred on the darker skin-tone.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1320-1322
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• 1994

Photoisomerization characteristics of 4-octyl-4'-(5-carboxy-pentamethyleneoxy) azobenzene molecules (8A5H) were attained by measurement of absorbtion spectra. 8A5H in chroloform($6.0{\times}10^{-5}[M/l]$) shows trans to cis and cis to trans isomerization by irradiation of lights of 360[nm] and 450[nm] wavelength. From LB monolayer films of 8A5H, also the cis/trans photoisomerization was obtained and it has reversibility and memory characteristics. We are now trying to detect these properties of 8A5H electrically. On this paper, we investigated the structural changes of monolayer on the water surface by measuring the displacement current as a preliminary experiment. The measuring system was constructed at home-made Kuhn type LB(Langmuir-Blodgett) deposition apparatus. 8A5H solution was spreaded at the air-water interface and the currents induced by the dynamic behavior of molecules were measured when the molecules were pressed by barrier. The reversibility of displacement currents by compression and expansion was obtained from 8A5H molecules, which shows the compressed molecules have a tendency to disperse after the compression. From this experiment, we conclude that the behavior of molecules on water surface can be monitored electrically by using this current measuring method, and this method can also be applied to detect the photoisomerization of monolayers on water surface.

• 유통과학연구
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• 제15권6호
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• pp.57-64
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• 2017

Purpose - The purpose of this study is to investigate the effect of brand message type on the object relevance between consumers and brands and to identify the mediation role of the object relevance in the effect of the message type on brand attitude. Research design, data, and methodology - Types of pride are classified into hubristic pride and authentic pride, and brand message types are divided into ability message and warmth message. Restaurant brand was selected by empirical study, and the experiment was performed with 2 (pride type: hubristic versus authentic) × 2 (message type: ability message versus warmth message) between-subjects design. The subjects of the experiment consisted of the undergraduates taking courses related to marketing. A preliminary step was taken to explore the difference in the perceived level of object relevance induced from each type of message between the consumer group that felt hubristic pride and the other group that felt authentic pride. This study analyzed the mediating role of the object relevance in the effects of the message type on brand attitude by means of Bootstrap method for each of the pride groups. Results - The results from the empirical analysis are summed up as follows. Regardless of pride types they felt in advance, consumers perceived their object relevance to be higher in the warmth information message than in the ability information message, and object relevance was analyzed to have a positive effect on brand attitude. It was analyzed that, regardless of pride types, object relevance played full mediation roles in the effect of warmth information versus ability information message on brand attitude. Conclusions - Based on the results, it may be suggested that marketers of a brand should endeavor to develop a warmth information message rather than a ability information message to prompt consumers to perceive the object relevance between their own brands and consumers, regardless of pride types, as long as a consumer feels pride in advance. In order to increase the consumers' attitude toward their brand, the brand marketers are solicited to check the object relevance between their brand and consumers, then, seek for the managerial ways to promote such object relevance.