• 지구물리와물리탐사
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• 제12권1호
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• pp.8-16
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• 2009

주파수 영역 항공 전자탐사 자료의 holistic 역산은 사전정보가 충분한 경우에 측정 자료의 보정, 처리 및 역산을 동시에 진행하는 역산법으로 개발되었다. 이 연구에서는 사전정보가 없는 경우에도 적응 가능하도록 holistic 역산을 발전시킨다. 이 역산에서는 수직방향으로 전기적 물성이 부드럽게 변화하는 다층 구조를 가정하고, 시스템 오차로 인한 편향 매개변수를 단순화하며. 고도에 따른 수평 방향의 평활화 조건을 적용하고, 클러스터를 이용하여 병렬 계산을 수행한다. 사전정보를 전혀 이용하지 않고 holistic 역산법으로 800만 개의 자료를 340만 개의 매개댄수에 대해 역산한 결과, 이와는 별개로 계산된 보정 계수, 다운홀 로깅 자료 및 지하수위 자료와 잘 일치하는 결과를 굴을 수 있었다. 이로부터 holistic 역산의 성공 여부가 정교하게 작성된 초기 모형이나 탐사 지역의 특별한 사전정보와는 무관함을 알 수 있었다. 또한. holistic 역산은 높은 고도에서의 원점 측정을 필요로 하지 않으므로 자료 획득에 필요한 비용을 상당히 절감할 수 있을 것이다.

• 복식문화연구
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• 제18권2호
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• pp.337-347
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• 2010

The purpose of this study was to figure out consumer's recognition on brand's peculiar style on Korean contemporary women's apparel brand. The contemporary women's apparel brands show advanced and stylish merchandise at better price points. This segment of the Korean ready-to-wear market has been growing fast in last decades. Four contemporary women's apparel brands(I, K, M, and T) were participated in this study. The data(n=216) were collected with questionnaire survey at 24 apparel retail shops in metro Seoul area. The questionnaire measured the consumers' recognition on each brand's peculiar style. The subjects evaluated each brand's typical silhouette, materials, and style image. The results of the survey showed that the style image factors were 'stylish', 'simple', 'casual', 'feminine', and 'classic'. The style image of each brand was differentiated from others. The brand T had classic image, the brand K had simple and casual image, brand M had stylistic image, and the brand I had feminine image. The features of materials that used at the four brands were not very different by the brands. They used the high valued materials. The common features of the materials were 'smooth', 'thin' and 'light weight.'

• 대기
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• 제20권2호
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• pp.73-89
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• 2010

An updateable model output statistics (UMOS) system for daily maximum and minimum temperature ($T_M$ and $T_m$) over South Korea based on the Canadian UMOS system were developed and validated. RDAPS (regional data assimilation and prediction system) and KWRF (Korea WRF) which have quite different physics and dynamics were used for the development of UMOS system. The 20 most frequently selected potential predictors for each season, station, and forecast projection time from the 68 potential predictors of the MOS system, were used as potential predictors of the UMOS system. The UMOS equations were developed through the weighted blending of the new and old model data, with weights chosen to emphasize the new model data while including enough old model data to ensure stable equations and a smooth transition of dependency from the old model to the new model. The UMOS equations are being updated by every 7 days. The validation results of $T_M$ and $T_m$ showed that seasonal mean bias, RMSE, and correlation coefficients for the total forecast projection times are -0.41-0.17 K, 1.80-2.46 K, and 0.80-0.97, respectively. The performance is slightly better in autumn and winter than in spring and summer. Also the performance of UMOS system are clearly dependent on location, better at the coastal region than inland area. As in the MOS system, the performance of UMOS system is degraded as the forecast day increases.

• 한국수산과학회지
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• 제44권6호
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• pp.635-643
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• 2011

Agar was prepared from Gelidium amansii collected from Jeju Island, South Korea. This agar preparation has high gel strength and low sulfate content compared with G. amansii agar from Morocco. Accordingly, agarose was made from the Jeju agar through the consecutive refining processes of dimethyl sulfoxide (DMSO) extraction and ethylene diamine tetra acetic acid (EDTA) washing. The physicochemical properties of the resulting agarose were compared with those from agarose prepared using only DMSO extraction. Consecutive DMSO extraction and EDTA washing more strongly affected the physicochemical properties of the agarose (purified agarose) compared with the use of DMSO extraction alone. These properties were similar to those of commercial agarose used for electrophoresis. In DNA electrophoresis, the separation and movement speed of the purified agarose were similar to those of the commercial agarose. In a $^{13}C$ NMR analysis, the purified agarose exhibited the same carbon peak as the commercial agarose. When observed under scanning electron microscopy, the agar had an even and smooth surface without irregularities or pores, and the purified agarose had a wide surface area with a large number of pores; the commercial agarose had an irregular surface that would allow the solvent to easily permeate. These results illustrate that the physicochemical properties of agarose prepared from DMSO extraction and EDTA washing were more effective than those observed after DMSO extraction alone; thus, these processes used in succession will be useful in agarose industries.

• Wind and Structures
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• 제20권1호
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• pp.15-36
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• 2015

Characterization of wind flows over a complex terrain, especially mountain-gorge terrain (referred to as the very complex terrain with rolling mountains and deep narrow gorges), is an important issue for design and operation of long-span bridges constructed in this area. In both wind tunnel testing and numerical simulation, a transition section is often used to connect the wind tunnel floor or computational domain bottom and the boundary top of the terrain model in order to generate a smooth flow transition over the edge of the terrain model. Although the transition section plays an important role in simulation of wind field over complex terrain, an appropriate shape needs investigation. In this study, two principles for selecting an appropriate shape of boundary transition section were proposed, and a theoretical curve serving for the mountain-gorge terrain model was derived based on potential flow theory around a circular cylinder. Then a two-dimensional (2-D) simulation was used to compare the flow transition performance between the proposed curved transition section and the traditional ramp transition section in a wind tunnel. Furthermore, the wind velocity field induced by the curved transition section with an equivalent slope of $30^{\circ}$ was investigated in detail, and a parameter called the 'velocity stability factor' was defined; an analytical model for predicting the velocity stability factor was also proposed. The results show that the proposed curved transition section has a better flow transition performance compared with the traditional ramp transition section. The proposed analytical model can also adequately predict the velocity stability factor of the wind field.

• 해양환경안전학회지
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• 제23권1호
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• pp.104-111
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• 2017

본 연구는 원심펌프 내부 유동장 특성에 대한 시뮬레이션 및 시각화에 중점을 둔다. 3D 수치해석은 Reynolds Average Navier-stock 코드를 k-${\varepsilon}$ 표준 2차방정식 난류 모델로 처리하여 수행하였다. 시뮬레이션은 흡입측, 임펠러, 토출측 영역에서 조도로 인한 마찰 손실과 임펠러 웨어링에서 체적 손실을 포함한다. 해석과 실험사이의 성능곡선 비교결과 최대 5 %의 작은 차이를 보이며 동일한 추세를 나타냈다. 최고 효율점에서 속도 벡터는 고르게 나타났지만 비 설계점에서는 현저한 변화가 나타났고, 텅 부근의 임펠러 유로토출부에서 강력한 재순환 영역이 나타났다. 비교적 일정한 압력분포가 텅 부근임에도 불구하고 임펠러 주위에 관찰되었다. 볼류트 내에서 기하학적으로 인해 형성된 나선형 와류가 이 영역에서 유동장이 상대적으로 난류이고 불안정하다는 것을 증명하였다.

• Journal of Yeungnam Medical Science
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• 제2권1호
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• pp.293-297
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• 1985

저자들은 최근 50세 남자 환자에서 병리조직학적으로 증명된 정상피종과 태아성 암으로 구성된 결합종양 1예를 경험하였기에 문헌 고찰과 아울러 보고하는 바이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.967-972
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• 2004

The role of transfer films formed during sliding of polymer composites against steel counterfaces was studied in terms of the tribological behaviors of composites. Four kinds of composites were included in this study: (1) unfilled PPS, (2) PPS+2%CuO, (3) PPS+2%CuO+5% carbon fiber (CF), and (4) PPS+2%CuO+15%Kevlar. The filler material CuO was in nanoscale particulate form and the reinforcing material was in the form of short fibers. The composites were prepared by compression molding at $310^{\circ}C$ and sliding tests were run in the pin-on-disk sliding configuration. The counterface was made of tool steel hardened to 55-60 HRC and finished to a surface roughness of 0.09-0.10 ${\mu}m$ Ra. Wear tests were run for 6 hrs at the sliding speed of 1 m/s and contact pressure of 0.65 MPa. Transfer films formed on the counterfaces during sliding were investigated using AFM and SEM. The results showed that as the transfer film became smooth and uniform, wear rate decreased. PPS+2%CuO+15%Kevlar composite showed the lowest steady state wear rate in this study and its transfer film showed the smoothest and the most uniform characteristics. The examination of worn surfaces of PPS+2%CuO composite using X-ray area scanning (dot mapping) showed back-transfer of steel counterface material to the polymer pin surface. This behavior is believed to strengthen the polymer pin surface during sliding thereby contributing to the decrease in wear rate.

• 천문학논총
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• 제21권2호
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• pp.43-49
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• 2006

The KASINICS (KASI Near Infrared Camera System) is a ground-based Near-Infrared (NIR) imaging instrument developed by the Korea Astronomy and Space Science Institute (KASI). In this paper, we report the test results of the KASINICS camera optics system which is comprised of a 1-1 Offner relay. We measure that the surface RMS fluctuations of the Offner mirrors are at the level of $10^{-1}-10^{-2}$ of the target wavelengths, showing that the mirrors are sufficiently smooth for NIR observations. The alignment of the Offner optics system has been checked too. Our ray-tracing simulations find that the image quality should not degrade more than the pixel size of the KASINICS ($40{\mu}m$), if a de-centering or a tilt of the Offner mirrors are within 5mm, or $2.5^{\circ}$. Our measurement shows that the de-centering or the tilt of the Offner mirrors are less than 1 mm or $0.5^{\circ}$, assuring that the KASINICS image quality are not affected by the alignment errors. We have also measured that the optics resolution is $20{\mu}m$ and it does not degrade more than 10% over the detector surface area of 14.3 mm ${/times}$ 14.3mm. Overall, we conclude that the KASINICS optics system satisfies the design requirements for NIR imaging observations.

• 폴리머
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• 제36권2호
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• pp.202-207
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• 2012

슈도모나스를 함유하는 poly(${\varepsilon}$-caprolactone)(PCL) 마이크로캡슐은 다중에멀젼 시스템에 의하여 제조하였고, 제조조건에 따른 마이크로캡슐의 특성과 방출거동에 대하여 조사하였다. 마이크로캡슐의 형태와 입도분포는 주사전자현미경과 입도분석기를 이용하여 관찰하였고, 방출거동은 액체배양법을 통하여 확인하였다. 다양한 제조조건에 따라 제조된 마이크로캡슐은 10~60 ${\mu}m$의 입자크기와 표면이 매끈하고 균일한 구형의 마이크로캡슐이 형성됨을 확인하였다. 열분석 결과, 마이크로캡슐은 약 $58^{\circ}C$에서 용융피크를 나타내었고 벽재물질의 함량 증가에 따라 용융열이 증가함으로써 벽재의 두께는 PCL 함량에 비례함을 확인할 수 있었다. 또한 슈도모나스의 방출속도는 유화제 함량, 교반속도, PCL 함량에 따라 조절이 가능하며 이는 유화제 함량과 교반속도 증가에 따른 입자 크기의 감소에 의한 비표면적 증가와 벽재물질의 두께 증가에 인한 방출속도의 감소에 의한 것으로 판단된다.