• 한국방사선학회논문지
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• 제17권5호
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• pp.685-691
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• 2023

본 연구는 흉부 후·전방향 검사 시 보조관심영역의 변화가 노출지수와 선량에 미치는 영향에 대한 연구를 통해, 임상에서 적절한 보조관심영역 적용에 대한 인식을 제고하고자 한다. 본 연구는 흉부 모형 팬텀을 대상으로 하였고, 조사조건은 120 kVp, 200 mA, 2 mAs로 설정하였으며, 조사야 크기는 영상수용체 전체를 포함하는 크기(17 X 17")를 적용했다. Sub-ROI는 장비 제조사에서 제공하는 다섯 가지 방식(AEC, VR, HR, LS, SS)를 이용하였다. Sub-ROI 변화에 따른 EI의 평균값은 AEC의 경우 135.58 ± 0.89, VR은 100.80 ± 0.80, HR은 143.43 ± 0.76, LS는 103.22 ± 0.68, SS는 102.79 ± 0.84로 나타났으며, ESD의 평균값은 AEC의 경우 30.28 ± 0.50 µGy, VR은 30.16 ± 0.44 µGy, HR은 30.30 ± 0.46 µGy, LS는 30.23 ± 0.46 µGy, SS는 30.28 ± 0.51 µGy으로 측정되었다. 본 연구 결과, EI는 제조사에서 권고하는 AEC 모드를 기준으로 VR (25.7%)과 LS (23.9%), SS (24.2%)모드는 감소하였으며, HR 모드는 5.7% 증가하였다. 하지만, ESD는 Sub-ROI 변화에 영향을 받지 않았다. 그러므로 임상에서 Chest PA 검사 시 Sub-ROI에 따라서 EI가 변경될 수 있으니, 임상에서는 이점을 유의하여 검사조건 설정 시 Sub-ROI를 적절하게 사용해야 한다고 사료된다.

• 대한수의학회지
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• 제36권2호
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• pp.395-403
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• 1996

Monoclonal antibodies(MAbs) against field isolates of the bovine rotavirus A strain(G6), V strain(G10) and reference I-801 strain(G8) were produced and characterized. Six MAbs(4C2, 4D9, 5E1, 5E7, 5D5, 3E4) against A strain had neutralizing activity and reacted only with the G6 bovine rotaviruses determined by fluorescence focus neutralization (FFN) test. Otherwise, five neutralizing MAbs(1G2, 2G6, 5E2, 5E12, 5H7) against I-801 strain neutralized the G6 and G8 bovine rotaviruses. Five non-neutralizing MAbs(5F12, 7F12, 5E11, 2A11, 2B12) were VP6-specific and cross-reacted with all bovine and porcine rotaviruses examined by fluorescence antibody(FA) test. None of the MAbs reacted with bovie viral diarrhea virus(BVDV) and bovine coronavirus(BCV) determined by FA and FFN test.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3459-3469
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• 2022

Matrix composites of n-WO₃/n-Bi₂O₃/PVA with different loadings of n-WO₃/n-Bi₂O₃ mixtures (0-15 wt%) and starch (0 and 3 wt%) were fabricated by using melt-mixing method. The X-ray attenuation capability were evaluated based on mass attenuation coefficient (μ/⍴) using a general diagnostic X-ray machine at 40-100 kVp. The effect of starch addition on the dispersion of the fillers in the PVA matrix were observed by using FESEM through morphological analysis. The fabricated samples have shrunken and caused their thickness to be decreased (0.35 mm-0.55 mm) after the drying process even though fixed thickness (2.0 mm) was set initially. The density and HVL values of the samples with 3 wt% starch was seen lower than samples without starch (0 wt%), however the former have provided improvement in filler dispersion and better X-ray attenuation capability compared to the latter. As conclusion, the matrix composite of n-WO₃/n-Bi₂O₃/PVA with 15 wt% of n-Bi₂O₃, 8 wt% of n-WO₃ and 3 wt% starch can be selected as the best promising candidate for X-ray shielding materials.

• 한국의학물리학회지:의학물리
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• 제27권1호
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• pp.31-36
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• 2016

본 연구에서는 이중에너지 영상을 획득하는 방법으로, 구리판을 이용한 에너지 변조 필터를 사용하였을 때의 선량을 계산 및 측정하였고, 기존의 다른 방법들과 선량을 비교하였다. 몬테칼로 전산모사를 이용하여 에너지 변조 필터에 의한 선량 변화를 평가하기 위하여 MCNPX를 사용하였다. 두경부, 흉부, 복부 촬영에 주로 사용되는 관전압인 80, 120 kVp에 대한 스펙트럼을 SPEC78 프로그램으로 생성하여 선원을 모사하였고, 구리 물질로 이루어진 에너지 변조 필터(밀도: $8.96g/cm^3$)는 두께를 0.5 mm부터 2.0 mm까지 0.5 mm 간격으로 변화시켜가면서 선원으로부터 20.0 cm 거리에 X-선 창을 절반만 가리도록 모델링 하였다. 몬테칼로 전산모사 값과 실제 선량 값을 비교하기 위해서는 교정 상수가 필요하므로, Gafchromic EBT3 필름에 알고 있는 선량을 조사한 후 판독하여 선량 교정 곡선을 획득하였다. 실험과 동일한 조건으로 MCNPX의 f6 tally로 획득한 결과값과 측정값 간의 선량 환산 인자는 $7.2*10^4cGy/output$으로 구해졌으며, 관전압 80 kVp과 관전류 6 mA의 조건으로 콘빔 CT 촬영 시, 평균 10.1 cGy (표준편차 2.7 cGy) 조사됨을 알 수 있었다. 에너지 변조 필터에 기반한 이중 에너지 영상 획득 기술을 적용한 본 연구에서는 이중 에너지 콘빔 CT 시스템의 선량이 단일 에너지 CT 시스템의 선량보다 33~40% 감소함을 알 수 있다. 또한, 에너지 변조 필터에서 발생한 산란선에 의한 선량 증가 효과는 거의 없었다. 따라서, 인체 내 물질 분별력이 우수하여 임상에 널리 응용되었던 기존 이중 에너지 CT 시스템의 상대적으로 피폭선량이 높다는 단점을 효과적으로 개선할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.222-223
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• 2011

본 논문은 인천지역 345kV 계통고장전류 저감을 위한 한류리액터 설치에 따른 362kV 50kA 차단기의 과도회복 전압 정격 초과 여부를 EMTP을 활용하여 검토하였다. 과도회복전압(TRV : Transient Recovery Voltage)은 크게 두가지, 최대전압(Vp)과 초기과도회복전압상승율(RRRV:Rate of Rise of Recovery Voltage)로 구분하며, 리액턴스 성분이 증가하며 RRRV가 상승하여 차단기가 고장전류을 차단시 절연파괴(열파괴)로 이어질 수 있다. IEC 62271-100 규정에는 RRRV를 정격차단전류의 100% 크기(T100%) 차단시 2kV/us이내로 규정하고 있으며 이 보다 작은 전류의 T90, T75 차단시의 규정치는 계산식에 의해 정해진다.

• 한국경영과학회지
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• 제24권2호
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• pp.81-94
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• 1999

ATM network design procedure is different from the current circuit or packet networks design procedure because of the variety of the offered services and the variability of requested bandwidth for each connection of ATM network. A number of optimization models for the link dimensioning of ATM network design have been proposed in the literature. However, most of the literature did not consider the modularity of resources allocated to a transmission path and the non-bifurcation of a VP link over the more than one TP, which are standardized in recent ITU-T Recommendations. In thIs paper, we propose a mathematical model for link dimensioning of ATM networks, based on the network synthesis method and a generalized bin-packing problem. The suggested model satisfies the constraints mentioned in the ITU-T Recommendations. We also propose efficient and practical algorithms for the suggested model. Computational experiment shows that the suggested algorithm gives efficient solutions even for moderate and large-sized networks within reasonable time.

• 한국의류학회지
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• 제26권6호
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• pp.865-876
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• 2002

The purpose of the study is to clarify yellow image and formative properties in modern fashion. For the study of formative properties 230 kinds of costume samples being visual power in yellow have been selected from photographs in fashion magazines and divided into tones: vivid(S, B, Dp), vague(L, Lgr, D), bright(Vp, P, B). For the study of image 30 kinds of costume samples is used. The Study was measured by using Semantic Differential method. The subjects were 50 students majoring in clothing and textile. The data were analyzed by factor analysis, ANOVA, MDS and regression analysis. The results of analysis are as follow: 1. Factor analysis has extracted 4 factors of yellow image in the fashion. These factor are Attractiveness, Cheerfulness, Hardness and Softness, Gorgeousness. 2. There were significant difference in visual evaluation of yellow tones. 3. Evaluative dimensions of yellow was classified as Soft-Hard, Gorgeous-Unpretentious. 4. The mage effect on Preference, Buying needs, Pleasant and Riches was consist of complicated sensibility.

• 대한방사선기술학회지:방사선기술과학
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• 제21권2호
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• pp.57-63
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• 1998

AEC was designed to assist in the production of radiographs of equal density and to aid in the production f consistently high quality radiographs. Many improvements have been made in the AEC and these have helped to increase it's acceptance. Newer system (Falling load) control kVp and mA as well as exposure time. Authors have had experiments about the characteristics of AEC by Zone System. Zone System is the method to detection of photographic image qualify by control the photo print from Fred Archer and Ansel Adams. With the Zone System theory the experiments of density control, characteristics of phantom thickness and reproducibility of occupation rate of contrast media could make quality control of X-ray photography effectively in falling load system.

• 대한방사선기술학회지:방사선기술과학
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• 제21권2호
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• pp.11-18
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• 1998

Single phase, narrow beam X-ray attenuation data were obtained using various construction materials concrete, white block, red block, 3 hole block, gypsum board, artificial marble, cement, plate glass, wood, and lead. Tube voltages of 60, 80, 100, 120 kVp were employed and the resulting curves were compared to transmission data found in this report. The shielding methodology and the derivation of equations used for determination of barrier requirements were presented in NCRP 49. We could calculate the X-ray exposed dose after attenuation and thickness of protection barrier in the clinic facilities accordingly. For the purpose of maximizing the benefit/cost ratio to diagnostic shielding, various construction materials must be installed carefully and attnuation rate considered thoroughly.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.198-198
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• 2006

We have identified sodium benzanilide (Na-BA), sodium diphenyl amine (Na-DPA) and sodium deoxibenzoin (Na-DB) as very efficient initiators for the living anionic polymerization of HIC. It has a slow propagation rate with the additive function of chain end protection, offering in the process a perfect control over MW and MWD. The well-defined amphiphilic coil-rod, coil-rod-coil, and rod-coil-rod block-copolymers of PHIC and P2VP with controlled architecture have been synthesized for the first time with ${\sim}100\;%$ yields. The resulting block copolymers showed lamellar film, donuts, solid and hollow micelles, by simply varying the solvents and the block compositions.