• 수산해양기술연구
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• 제51권3호
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• pp.405-413
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• 2015

Acoustic target strength (TS) measurement and theoretical acoustic scattering models were applied to estimate the TS for assessing the fish biomass. TS measurement was made of ex situ sailfin sandfish Arctoscopus japonicus at 70 and 120 kHz, and then compared to backscatter model prediction. The live sandfish was tethered in seawater using monofilament lines. Measurements were made versus incidence angle, $-50^{\circ}$ to $50^{\circ}$ relative to dorsal aspect directions. Distorted wave Born approximation (DWBA) model was used to calculated TS pattern. The TS values of sandfish (body length: 16.2 cm) at 70 and 120 kHz were -66.94 dB and -64.45 dB, respectively, and were about 20 dB lower than TS of other fishes in Korea waters. These TS levels were distributed within the range of the theoretical TS. Ex situ measurement and theoretical TS may be applied to improve acoustical detection and biomass estimation of the sandfish, and is necessary to measure with various lengths.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.130-135
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• 2005

일체형 코드에서는 접촉 불량, 기계적 충격 등의 부주의한 사용에 의해 전기화재가 자주발생하고 있다. 본 논문에서는 비닐코드 및 고무코드 등의 일체형 코드의 화재확산 패턴을 조사하기 위해 벽면모델을 모의하였다. 화재진행과 확산패턴은 고속카메라를 이용하여 측정하였다. 실험결과로부터, 일체형 코드의 화재패턴은 섬광, 비산 그리고 완전이탈 순으로 진행하였다. 외부화염에 의해 비닐코드가 고무코드보다 단락이 쉽게 발생하였다. 일체형 코드가 완전 이탈이 된 경우, 비닐코드는 착화에너지가 감소함에 따라 더 이상의 화재 진전은 이루어지지 않았지만, 고무코드는 연속적으로 화재가 진행하는 것을 알 수 있었다.

• 비파괴검사학회지
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• 제17권1호
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• pp.11-22
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• 1997

원자력발전소 압력용기 및 배관은 많은 용접부를 포함하고 있으며 용접부내 결함은 크기, 위치 및 형태에 따라 압력용기 및 배관의 건전성에 커다란 영향을 미친다. 따라서 주요 압력용기와 배관의 용접부에 대해서는 가동 전 중 검사시 초음파 탐상시험을 실시하여 그 건전성을 확인하고 있다. 초음파 결함 신호로부터의 결함 분류는 비파괴 평가에 있어 매우 중요하며 초음파 형상 인식 방법이 적당하다. 본 논문에서는 탄소강 압력용기 용접부에 내재하는 결함으로부터 얻어진 초음파 결함 신호의 형상 인식을 위한 절차로써 데이터 수집, 특징 추출, 특징 선택 및 결함 분류를 하였으며, 결함 분류에 있어 결함의 종류를 크게 선형(linear)과 체적(volumetric)의 두 종류로 분류함에 있어 퍼지이론을 적용하여 퍼지이론을 적용한 초음파 형상 인식 기법의 가능성 및 효율성을 제시하였고 그 결과 기존의 분류기(classifier)들에 비해 보다 우수한 결과를 얻을 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.53-53
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• 2011

As the dimension of Cu interconnects has continued to reduce, its resistivity is expected to increase at the nanoscale due to increased surface and grain boundary scattering of electrons. To suppress increase of the resistivity in nanoscale interconnects, alloying Cu with other metal elements such as Al, Mn, and Ag is being considered to increase the mean free path of the drifting electrons. The formation of Al alloy with a slight amount of Cu broadly studied in the past. The study of Cu alloy including a very small Al fraction, by contrast, recently began. The formation of Cu-Al alloy is limited in wet chemical bath and was mainly conducted for fundamental studies by sputtering or evaporation system. However, these deposition methods have a limitation in production environment due to poor step coverage in nanoscale Cu metallization. In this work, gap-filling of Cu-Al alloy was conducted by cyclic MOCVD (metal organic chemical vapor deposition), followed by thermal annealing for alloying, which prevented an unwanted chemical reaction between Cu and Al precursors. To achieve filling the Cu-Al alloy into sub-100nm trench without overhang and void formation, furthermore, hydrogen plasma pretreatment of the trench pattern with Ru barrier layer was conducted in order to suppress of Cu nucleation and growth near the entrance area of the nano-scale trench by minimizing adsorption of metal precursors. As a result, superconformal gap-fill of Cu-Al alloy could be achieved successfully in the high aspect ration nanoscale trenches. Examined morphology, microstructure, chemical composition, and electrical properties of superfilled Cu-Al alloy will be discussed in detail.

• 정보관리연구
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• 제39권4호
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• pp.241-257
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• 2008

이 연구는 University of Mysore의 과학기술 분야 연구자들이 수행한 연구성과의 성장과 기여, 영향에 대해 분석하였다. 또한 이 대학 소속 과학자들의 커뮤니케이션 패턴을 분석하고 서로 다른 저널에 발표된 연구성과의 집중 및 분산 정도를 조사한다. 평균인용도의 측면에서 이 대학이 강점과 약점을 가지고 있는 연구영역, 성장률과 영향, 학과별 연구동향에 대해 분석하였으며, 전반적인 수준과 주제분야별, 국가별로 연구성과의 국제적 협력에 대해 조사한다. 인용빈도가 높은 논문과 생산성이 높은 저자의 특성에 대해서도 분석하였다.

• 한국전자파학회논문지
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• 제15권2호
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• pp.121-126
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• 2004

본 논문에서는 calibration된 scatterometer를 이용하여 SAR 데이터를 보정하는 연구 결과를 선보인다. 도체구를 이용하여 안테나 주빔에서의 polarimetric한 안테나 패턴(크기와 위상)을 측정하고, 이 데이터를 이용하여 차량 탑재형 네트워크 분석기형 scatterometer 시스템을 polarimetric하게 정확하게 보정하였다. 이 scatterometer를 이용하면 잔디밭, 논, 맨땅 등의 지표면에 대한 정확한 Mueller 행렬을 얻을 수 있으므로, 레이더 산란계수뿐만 아니라 위상변수들도 정확하게 측정하게 된다. 또한, 대부분의 SAR 시스템에는 위상변수 측정에 에러가 있게되고, polarimetric하게 보정된 scatterometer로 SAR가 측정하는 지역을 동시에 측정하여 SAR 데이터를 교정할 수 있다. 이러한 polarimetric한 보정 방법을 이용하면, 산란계수의 보정효과는 크지 않으나, hh-편파와 vv-편파간의 위상변수인 degree of correlation $\alpha$의 보정효과는 매우 큼을 알 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제40권6호
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• pp.353-356
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• 2010

Although liposomes have been applied as drug delivery systems in various fields, the usage was limited due to the low encapsulation efficiency compared to other carrier systems. Here, cationic liposomes were prepared by mixing 1,2-dioleoyl-3-trimethylammoniopropane (DOTAP) as a cationic lipid, 1,2-dioleoyl-sn-glycerol-phosphoethanolamine (DOPE) and cholesterol (CH), and the liposomes were hydrated by varying the aqueous phases such as phosphate-buffered saline (PBS), 5% dextrose, and 10% sucrose in order to improve the encapsulation efficiency of bovine serum albumin (BSA). The particle size and zeta potential were determined by dynamic light scattering method and in vitro release patterns were investigated by spectrophotometry. Particle size and zeta potential of liposomes were varied depending on the ratio of DOTAP/DOPE/CH in range of 270-350 nm and 0.8-9.7 mV, respectively. Moreover, the addition of polyethylene glycol (PEG) improved the encapsulation efficiency from 37% to 43% as well as reduced particle sizes of liposomes while the liposomes were hydrated in PBS. When the liposomes were hydrated with 10% sucrose, the encapsulation efficiency of BSA was higher than any other groups. Whereas PBS was used as hydration solution, lower encapsulation efficiency was obtained compared with other groups. More than 60% of BSA was released from the liposomes hydrated with 10% sucrose; thereafter another 20% of BSA was released. Therefore, release pattern of BSA from cationic liposomes was extended release in this study. From the results, cationic liposomes dispersed in 10% sucrose would be potential carrier with high encapsulation efficiency.

• Advances in materials Research
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• 제3권3호
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• pp.139-149
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• 2014

Surface enhanced Raman Scattering (SERS) has attracted attention because the technique enables detection of various chemicals, even down to single molecular scale. Among the diverse candidates for SERS substrates, Au nanoparticles are considered promising due to their fine optical properties, chemical stability and ease of surface modification. Therefore, the fabrication and optical characterization of gold particles on solid supports is highly desirable. Such structures have potential as SERS substrates because the localized surface plasmon resonance of gold nanoparticles is very sensitive to combined molecules and environments. In addition, it is well-known that the properties of Au nanoparticles are strongly dependent on their shape. In this work, arrays of shape-controlled Au nanoparticles were fabricated to exploit their enhanced and reproducible optical properties. First, shape-controlled Au nanoparticles were prepared via seed mediated solution-phase synthesis, including spheres, octahedra, and rhombic dodecahedra. Then, these shape-controlled Au nanoparticles were arranged on a PDMS substrate, which was nanopatterned using soft lithography of poly styrene particles. The Au nanoparticles were selectively located in a pattern of hexagonal spheres. In addition, the shape-controlled Au nanoparticles were arranged in various sizes of PDMS nanopatterns, which can be easily controlled by manipulating the size of polystyrene particles. Finally, the optical properties of the fabricated Au nanoparticle arrays were characterized by measuring surface enhanced Raman spectra with 4-nitrobenezenethiol.

• 한국재료학회지
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• 제29권2호
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• pp.116-120
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• 2019

We prepared $Y_3Al_5O_{12};Ce^{3+},Pr3^{+}$ transparent ceramic phosphor using a solid state reaction method. By XRD pattern analysis and SEM measurement, our phosphors reveal an Ia-3d(230) space group of cubic structure, and the transparent ceramic phosphor has a polycrystal state with some internal cracks and pores. In the Raman scattering measurement with an increasing temperature, lattice vibrations of the transparent ceramic phosphor decrease due to its more perfect crystal structure and symmetry. Thus, low phonon generation is possible at high temperature. Optical properties of the transparent ceramic phosphor have broader excitation spectra due to a large internal reflection. There is a wide emission band from the green to yellow region, and the red color emission between 610 nm and 640 nm is also observed. The red-yellow phosphor optical characteristics enable a high Color Rendering Index (CRI) in combination with blue emitting LED or LD. Due to its good thermal properties of low phonon generation at high temperature and a wide emission range for high CRI characteristics, the transparent ceramic phosphor is shown to be a good candidate for high power solid state white lighting.

• 환경영향평가
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• 제31권5호
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• pp.334-342
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• 2022

대기환경보전법이 강화되면서 야외저탄장을 옥내화 함으로써 외부로 날리는 비산먼지는 감소했지만, 저탄장에서 발생하는 석탄 비산먼지와 유해물질들을 단순히 격리함으로서 이러한 물질들이 내부에 축적되어 또 다른 문제를 야기할 수 있다. 본 연구는 이를 해결하기 위해 운영 중인 옥내 저탄장을 선정하여 내부 기류 흐름 양상과 환기량을 분석하였다. 옥내저탄장 내부 기류는 전반적으로 지형적으로 산 쪽에 접한 남서쪽으로 이동하는 경향을 보였다. 그리고 바다와 접한 북쪽 루버에서는 해풍에 의한 기류가 유입되고 있었다. 옥내저탄장 내부로 유입되는 총 유량은 918,691m³/h, 시간당 자연환기 횟수는 0.6회로 나타났다. 연구 결과를 바탕으로 내부 기류가 집중되는 위치에 강제 환기장치를 설치하는 것을 제안한다.