• 한국통신학회논문지
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• 제24권12A호
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• pp.1974-1984
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• 1999

본 논문은 정확한 전파 모델과 신속한 전파 예측 모델을 필요로 하는 다중 경로 현상을 효과적으로 획득하기 위해 효율적인 데이터 표현 구조를 제안한다. 본 논문은 ray tracing에서 사용되고 있는 VR(Vector Representation)을 향상시키기 위한 데이터 표현 구조로서, 빌딩과 같은 오브젝트를 표현하기 위해 CR(Circular Representation)을 이용하는 오브젝트 표현 방법을 제안한다. 제안된 CR은 건물의 중심에서 건물을 둘러싸도록 원을 그리는 형태이다. 본 구성에서 CR은 기하학적 구조를 위한 기본 빌딩 구조로서의 기능을 가지며, VR이 단독으로 사용되어 졌을 때 보다 더 많은 효율성을 증진시킨다. VR은 건물을 표현하기 위해 여러 개의 벽면 벡터를 필요로 하는 반면, CR은 하나의 원으로 표현된다. 결과적으로 제안된 방법에 의해 ray tracing에서 상당한 양의 계산 비용을 줄일 수 있다. 본 논문의 목표는 효율적인 ray tracing 예측 모델을 위해 데이터 구조화 시에 효율성을 얻기 위한 해결책으로서 CR을 제안하는 것이다. 본 논문은 제안된 방법에 의해 계산 부하량이 현저하게 줄어듬을 보인다. 또한 deterministic ray tracing 모델에서 CR의 계층? 구조의 수반 가능한 사용을 보인다. 시뮬레이션 결과는 계층적 octree 구조가 약 50% 계산 부하를 감소시키고 있는 반면 본 논문에서 제안된 CR은 분산된 물체의 수에 비례하여 계산 부하량을 현저하게 감소시킨다는 것을 나타낸다.

• 자원환경지질
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• 제27권5호
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• pp.491-498
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• 1994

2층구조 대지속에 존재하는 유한 크기의 불균질체로 인한 지자기 지전류 (MT) 응답을 적분방정식법으로 계산하였다. 적분방정식은 입사전자장과 3차원물체 내부의 산란전류를 층상대지에 적합한 전기적 텐서 그린함수를 통하여 연결시킨다. 본 논문에서는 3차원체의 MT응답에 미치는 표층과 기반층의 영향에 대하여 검토하였다. 표층은 탐사대상물의 검출을 방해하는 효과를 가지며 그 효과는 표층의 전기비저항이 높을 때보다 낮을 때가 더 뚜렷하다. 한편 기반은 상층의 3차원체에 인한 MT이상을 높이는 효과를 가져올 수도 있다. 전기비저항이 높은 기반이 존재하면 물체에 의한 전류의 미소변동은 보다 전기비저항이 낮은 상층에 한정되는 경향이 있다.

• 대한기계학회논문집A
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• 제40권7호
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• pp.647-652
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• 2016

유도초음파를 활용한 비파괴검사기법은 장거리 배관 검사에 많이 활용된다. 장시간 사용에 따라 배관에는 표면 부식과 같은 형태의 결함이 주로 발생한다. 표면 부식형 결함의 경우 장거리 유도 초음파 검사 기법을 활용한 신호 해석에 어려움이 있다. 상반 정리는 복잡한 수학적 표현을 간단히 나타내주는 기법으로 잘 알려져 있다. 상반 정리는 평판, 반무한체의 산란 문제를 해결하는데 이미 적용된 바가 있지만 원통형 구조물에서는 적용된 사례가 없다. 이 논문에서는 배관 진단을 위해 상용 장비에서 많이 사용되는 비틀림파의 산란 신호를 상반 정리를 적용하여 해석하였다. 산란 신호는 상반 정리를 활용하여 산란 체의 형태와 위치에 따라 단순한 닫힘 해로 표현하였다. 타원형 결함과 사각 결함의 폭과 깊이 변화에 따라 주파수 별로 발생되는 산란 신호가 계산되었으며, 주파수 증가에 따른 주기적인 결과를 나타내는 것을 확인하였다. 산란 신호 해석을 위한 닫힘 해는 결함의 크기를 정량적으로 해석하는데 중요한 역할을 할 것으로 기대된다.

• 수산해양기술연구
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• 제52권3호
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• pp.276-280
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• 2016

This study investigated luring distributions by water layer of common squid which were targeted by angling fishing vessels equipped with LED and metal-halide lamps using a scientific echosounder with a 120 kHz frequency in order to develop energy-effective underwater fish aggregation devices. In the analysis, angles of a transducer were changed from $0^{\circ}$ to $45^{\circ}$ and were rotated every $10^{\circ}$ horizontally. It was shown that common squid were densely distributed from the surface to 40 m and they were also distributed in directions of $10^{\circ}{\sim}+30^{\circ}$, $-30^{\circ}{\sim}-60^{\circ}$, and $-120^{\circ}{\sim}-130^{\circ}$with the head of vessel as the center. Comparative results of angles of transducer on acoustical densities of common squid distributing in 21~40 m water depth showed an average $101.8m^2/nm^2$ in vertical direction of $0^{\circ}$, $12.3m^2/nm^2$ in angle of $30^{\circ}$, and $42.4m^2/nm^2$ in angle of $45^{\circ}$, respectively. It implied that more considerations on acoustic scattering strength by incidence angle direction of the transducer and swimming oriental angle direction of common squid would be required.

• Food Science and Biotechnology
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• 제16권4호
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• pp.600-604
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• 2007

In this study, we first prepared 3 kinds of powders with different molecular masses from the crude protein-bound polysaccharide extract of Agraricus blazei Murill through ultrafiltration, followed by spray-drying. Then, the antitumor activities of the powders were analyzed. Size exclusion chromatography coupled with a multi-angle laser-light-scattering system showed the 3 powders had the following molecular ranges: below 10 kDa (SD-1), 10 to 150 kDa (SD-2), and above 150 kDa (SD-3), representing peak molecular weights of $8.26{\times}10^3,\;9.65{\times}10^4$, and $5.94{\times}10^6\;g/mol$, respectively. All the powders stimulated macrophage RAW264.7 cells to produce nitric oxide, of which SD-2 and SD-3 were superior to the crude extract powder (CP-SD), while SD-1 showed the lowest activity. Similar results were found for their cytotoxicities against human cancer cell lines (A549, MCF-7, and AGS), where the highest activity was obtained with the SD-2 treatment for 72 hr at $1,000\;{\mu}g/mL$. The MCF-7 cell line was less sensitive to the powders than the other cells. From this research we found that ultrafiltration, in combination with spray-drying, is applicable for preparing protein-bound polysaccharide powders with higher antitumor activities.

• Journal of Radiation Protection and Research
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• 제35권1호
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• pp.1-5
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• 2010

This study concerning the surface dose of eye and thyroid from panoramagraphy used thermoluminescent dosimeter (TLD) and photoluminescent dosimeter (PLD) to take measurements at ten hospitals in the Gwangju metropolitan area. The recommendations from ICRP 60 and ICRP 73 on the allowance standard for eye are 15 mSv and for thyroid is 1 mSv. The left eye TLD and PLD values are 0.19 mSv and 0.24 mSv respectively. The right eye TLD and PLD values are 0.23 mSv and 0.25 mSv respectively. Thyroid TLD and PLD values are 0.08 mSv and 0.25 mSv respectively and did not exceed the allowance standards(p<0.001). Also comparisons are made between TLD and PLD for each organ and PLD has higher dose measurements than TLD. There are statistically significant differences in left eye measurements and thyroid measurements (p<0.01). There is no significant difference in measurements for the right eye (p>0.05). The TLD and PLD measured dose from panoramagraphy instruments on eyes and thyroid from each hospital did not exceed the recommended dose from ICRP 60 for surface dose measurements. However, due to the probability of influence, consideration should be made for all levels of dose.

• 대기
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• 제29권5호
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• pp.525-535
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• 2019

Vertical distributions of aerosol mass concentrations over Seoul and Gangneung from January to February 2015 were investigated using aerosol Mie-scattering lidars. Vertical mass concentration of aerosol was calculated from the lidar data using KALION's algorithm and quantitatively compared with ground PM₁₀ concentration to obtain objectivity of data. The backward trajectories calculated using HYSPLIT (version 4) were clustered into 5 traces for Seoul and 6 traces for Gangneung, and the observed aerosol vertical mass distribution was analyzed for individual trajectories. Result from the analysis shows that, aerosol concentrations with in the planetary boundary layer were highest when airflows into the measurement points originated in the Shandong Peninsula or the Inner Mongolia. In addition, the difference of aerosol mass concentrations in the two regions below 1 km was about twice as large as that in the long range transport from the Shandong Peninsula compared to the local emission. This result shows that the air quality over Korea related to particulate matters are affected more by aerosol emissions in the upstream source regions and the associated transboundary transports than local emissions. This study also suggests that the use of local aerosol observations is critical for accurate simulations of aerosol-cloud interactions.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1369-1376
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• 2006

Self-organized nanogels were prepared from pullulan/biotin conjugates (PU/Bio) for the development of an effective anticancer drug delivery system. The degree of biotin substitution was 11, 19, and 24 biotin groups per 100 anhydroglucose units of pullulan. The physicochemical properties of the nanogels (PU/Bio1, 2 and 3) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all the samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CACs) of the nanoparticles in distilled water were $2.8{\times}10^{-2},\;1.6{\times}10^{-2}$, and $0.7{\times}10^{-2}mg/ml$ for the PU/Bio1, 2, and 3, respectively. The aggregation behavior of the nanogels indicated that biotin can perform as a hydrophobic moiety. To observe the specific interaction with a hepatic carcinoma cell line (HepG2), the conjugates were labeled with rhodamine B isothiocyanate (RITC) and their intensities measured using a fluorescence microplate reader. The HepG2 cells treated with the fluorescence-labeled PU/Bio nanoparticles were strongly luminated compared with the control (pullulan). Confocal laser microscopy also confirmed internalization of the PU/Bio nanogels into the cancer cells. Such results demonstrated that the biotin in the conjugate acted as both a hydrophobic moiety for self-assembly and a tumor-targeting moiety for specific interaction with tumor cells. Consequently, PU/Bio nanogels would appear to be a useful drug carrier for the treatment of liver cancer.

• Transactions on Electrical and Electronic Materials
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• 제7권3호
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• pp.112-117
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• 2006

In this paper we present that the effects of polymer adsorption on stabilities and CMP performance of ceria abrasive particles. Characterization of ceria abrasive particles in the presence of poly(vinyl pyrrolidone) (PVP) was performed by the measurements of adsorbed amounts of PVP, average sizes, and the back scattering intensities of the ceria abrasive particles as functions of PVP molecular weight and PVP concentration. The ceria abrasive particles in the presence of PVP were used to polish $SiO_2\;and\;Si_3N_4$ films deposited on Si wafers in order to understand the effect of PVP adsorption on chemical mechanical polishing (CMP) performance, together with ceria abrasive particles without PVP. Adsorption of PVP on the ceria abrasive particles enhanced the stability of ceria abrasive particles due to steric stabilization of the thick adsorbed layer of PVP. Removal rates of the deposited $SiO_2\;and\;Si_3N_4$ films by the ceria abrasive particles in the presence of PVP were much lower than those in the absence of PVP and their magnitudes were decreased with an increase in the concentration of free PVP chains in the dispersion media. This suggests that the CMP performance in the presence of PVP could be mainly controlled by the hydrodynamic interactions between the adsorbed PVP chains and the free ones. Moreover, the molecular weight dependence of PVP on the removal rates of the deposited films was hardly observed. On the other hand, high removal rate selectivity between the deposited films in the presence of PVP was not observed.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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• pp.268-279
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• 2003

The nano capsulation of the ceramide was a technique that capsulated ceramide III and tocopheryl linoleate at the mono-vesicle, so as to act the horny layer in skin. It was used 0.5-5.0 wt% of hydrogenated lecithin and 0.01~2.00 wt% of lysolecithin as the membrane-strengthen agents of the mono-vesicle, 5.0~10 wt% of propylene glycol and 5.0~10.0 wt% of ethyl alcohol made by high-pressure Microfluidizer. To enhance the moisturizing efficacy and treat an atopy skin, used ceramide III and tocopheryl linoleate as the active ingredients, and it was made the nano-capsule that synthetic emulsifiers were free. The optimal condition of capsulation of nano ceramide was as follows. The conditions were 3 times at 1,000bar and 60-7$0^{\circ}C$. The particle size showed 63.1$\pm$7.34 nm such as the transparence water as the results for measuring by the laser light scattering. A zeta potential value was -55.1$\pm$0.84 ㎷. The result of the clinical test, the moisturizing effect (in-vivo, n=8, p-value<0.05) was improved 21.15% compared to control, as well as it was improved 36.31 % before the treatment. Moreover, the effectiveness of atopy skin indicated positive reaction that patients were 10 volunteers.