• 공업화학
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• 제31권2호
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• pp.147-152
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• 2020

본 연구에서는 천연오일인 cashew nut shell liquid (CNSL)의 구성성분인 cardanol을 이용하여 내화학성이 향상된 에폭시계 수지용 반응성 희석제 제조 공정을 최적화하였다. 이를 위해 반응표면분석법 중 중심합성계획법을 이용하여 최적화과정를 설계하였다. 계량인자로는 cardanol/ECH 반응몰비, 반응시간, 반응온도이고, 반응치는 수율, 에폭시 당량(EEW), 점도이다. 기초실험으로부터 계량인자 범위를 각각 cardanol/ECH 반응몰비(2~4), 반응시간(4~8 h), 반응온도(100~140 ℃)로 설정한 후 최적화과정을 진행한 결과 최적의 조건은 cardanol/ECH 반응몰비(3.33), 반응시간(6.18 h), 반응온도(120 ℃)로 산출되었으며, 이 조건에서의 예측값은 수율(100%), EEW (429.89 g/eq.), 점도(41.65 cP)로 나타났다. 실제 실험을 통해 알아본 결과 오차율은 0.3% 이하로 나타나 중심합성계획모델을 이용하여 cardanol 원료 반응성 희석제의 제조 공정을 최적화할 수 있었다.

• 천문학회보
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• 제39권1호
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• pp.73-73
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• 2014

Several geometrical models (e.g., cone and flux rope models) have been suggested to infer 3-D parameters of CMEs using multi-view observations (STEREO/SECCHI) and single-view observations (SOHO/LASCO). To prepare for when only single view observations are available, we have made a test whether the cone model parameters from single-view observations are consistent with those from multi-view ones. For this test, we select 35 CMEs which are identified as CMEs, whose angular widths are larger than 180 degrees, by one spacecraft and as limb CMEs by the other ones. For this we use SOHO/LASCO and STEREO/SECCHI data during the period from 2010 December to 2011 July when two spacecraft were separated by $90{\pm}10$ degrees. In this study, we compare 3-D parameters of these CMEs from three different methods: (1) a triangulation method using the STEREO/SECCHI and SOHO/LASCO data, (2) a Graduated Cylindrical Shell (GCS) flux rope model using the STEREO/SECCHI data, and (3) an ice cream cone model using the SOHO/LASCO data. The parameters used for comparison are radial velocities, angular widths and source location (angle ${\gamma}$ between the propagation direction and the plan of the sky). We find that the radial velocities and the ${\gamma}$-values from three methods are well correlated with one another (CC > 0.8). However, angular widths from the three methods are somewhat different. The correlation coefficients are relatively not good (CC > 0.4). We also find that the correlation coefficients between the locations from the three methods and the active region locations are larger than 0.9, implying that most of the CMEs are radially ejected.

• 한국수산과학회지
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• 제49권4호
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• pp.436-444
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• 2016

Clamshells, which comprise more than 50% of a clam’s weight, are a major byproduct of the clam industry and are mainly composed of insoluble calcium carbonate. This study investigates the use of clamshells as a natural calcium resource. Highly soluble powdered calcium lactate (LCCL) was prepared from the calcined powdered shells of littleneck clams (LCCP) using response surface methodology (RSM) to predict optimum conditions. These conditions, as derived from pH, solubility, and yield of 11 LCCLs manufactured according to the RSM model, were 1.80 M lactic acid and 1.13 M LCCP. The actual values of pH (6.98), solubility (93.99%), and yield (351.23%) under the optimized conditions were as predicted. The derived LCCL exhibited a strong buffering capacity in the range of pH 2.78-3.90 when combined with less than 2 mL of 1 N HCl. The ranges of calcium content and solubility of LCCL were 7.7-17.5 g/100 g and 96.6-98.9%, respectively. Fourier transform infrared spectroscopy (FT-IR) of the LCCL identified it as calcium lactate pentahydrate, and field emission scanning electron microscopy (FESEM) revealed an irregular and rod-like microstructure. These results confirm the potential use of clamshells, converted to highly soluble organic acid calcium, as an additive to enhance calcium content in food ingredients.

• 천문학회보
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• 제39권1호
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• pp.61.1-61.1
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• 2014

GSH 006-15+7 is a Milky Way supershell discovered by Moss et al. (2012). This supershell shows large shell-like structures in H I velocity maps. We have analyzed FUV emission for the supershell regions based on the FIMS and GALEX observations. Bright FUV flux at the boundaries of the supershell is mostly originated from dust scattering of FUV photons by dust clouds which was also observed at the boundaries of the supershell. We could find the distance to the supershell can be closer more than 30% compared with the distance of 1500 pc suggested by Moss et al. (2012) from the dust scattering simulation. And we also found the albedo and the phase function asymmetry factor of interstellar grains were 0.30 and 0.40, respectively. The confidence range for the albedo covers the theoretical value of 0.40, but g-factor is rather smaller than the theoretical value of 0.65. The small g-factor might mean the environment of turbulent ISM of the supershell. Meanwhile, the excess of C IV and X-ray emissions in the inside of the supershell can support the existence of hot gas and cooling in the supershell. And the C IV and X-ray emissions are monotonically decrease as away from the center of the SNR. This indicates the size of the hot bubble has considerably shrunk. We applied a simple simulation model to the PDR candidate region of the lower part of the supershell and obtained a H2 column density N(H2) = 1017.0-18.0 cm-2 and total hydrogen density nH ${\geq}$ 10 cm-3. This result shows the PDR candidate region represents a transition region from the warm phase to the cool phase in the PDR.

• 수산해양기술연구
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• 제54권1호
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• pp.25-31
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• 2018

In this study, the differences of holding power according to the shape and weight distribution of concrete weight used in shellfish shell fishery were investigated through the experiments. To investigate the differences in shape, five bar-shaped concrete weights with the same length and different cross-sectional shapes were produced. The sectional shape of each weight was square, triangle, circle, small cross, and large cross (SQ, TR, CI, CR-S, CR-L). Ten rectangular parallelepiped weights with different bottom area and cross-sectional area were produced. To investigate the differences by the weight distribution, the holding power on the square model (SQ) with six 50 g weights at different positions was investigated. All the holding power was obtained by measuring the tensile force generated when the concrete weight was pulled at a constant speed on the sand. As a result, there were no differences in holding power between the ten rectangular weights. However, the experiment on weights with different cross-sectional shapes showed differences in holding power. The holding power was higher in the order of CR-L > CR-S > CI > TR > SQ. In the weight distribution test, the holding power was higher as the front side of the weight was heavier. Generally, the frictional force is the same even if the shape is different, when two objects have the same value in the weight and the roughness. On the other hand, it seems to have a large impact when the shape of the bottom is deformed in the course of pulling the object. Particularly, the larger the degree of protrusion like cruciform weights, the more the holding power increased while deeply digging the bottom. It is also likely that the holding power increases as the front weight increases.

• 천문학회지
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• 제48권2호
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• pp.155-164
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• 2015

In Kang (2015) we calculated the acceleration of cosmic-ray electrons at weak spherical shocks that are expected to form in the cluster outskirts, and estimated the diffuse synchrotron radiation emitted by those electrons. There we demonstrated that, at decelerating spherical shocks, the volume integrated spectra of both electrons and radiation deviate significantly from the test-particle power-laws predicted for constant planar shocks, because the shock compression ratio and the flux of inject electrons decrease in time. In this study, we consider spherical blast waves propagating through a constant density core surrounded by an isothermal halo with ρ ∝ r⁻ⁿ in order to explore how the deceleration of the shock affects the radio emission from accelerated electrons. The surface brightness profile and the volumeintegrated radio spectrum of the model shocks are calculated by assuming a ribbon-like shock surface on a spherical shell and the associated downstream region of relativistic electrons. If the postshock magnetic field strength is about 0.7 or 7 µG, at the shock age of ∼ 50 Myr, the volume-integrated radio spectrum steepens gradually with the spectral index from α_inj to α_inj + 0.5 over 0.1–10 GHz, where α_inj is the injection index at the shock position expected from the diffusive shock acceleration theory. Such gradual steepening could explain the curved radio spectrum of the radio relic in cluster A2266, which was interpreted as a broken power-law by Trasatti et al. (2015), if the relic shock is young enough so that the break frequency is around 1 GHz.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.347-350
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• 2004

A space radiation analysis has been used to evaluate an ability of electronic equipment boxes or spacecrafts to endure various radiation effects, so it helps design thicknesses of structure and allocate components to meet the radiation requirements. A comparison study of space radiation dose analysis programs SPENVIS Sectoring Tool (SST) and SIGMA II is conducted through some structure cases, simple sphere shell, box and representative satellite configurations. The results and a discussion of comparison will be given. A general comparison will be shown for understanding those programs. The both programs use the same strategy, solid angle sectoring with ray-tracing method to produce an approximate dose at points in representative simple and complex models of spacecraft structures. Also the particle environment data corresponding to mission specification and radiation transport data are used as input data. But there are distinctions between them. The specification of geometry model and its input scheme, the assignment of dose point and the numbers, the prerequisite programs and ways of representing results will be discussed. SST is a web-based interactive program for sectoring analysis of complex geometries. It may be useful for a preliminary dose assessment with user-friendly interfaces and a package approach. SIGMA II is able to obtain from RSICC (Radiation Safety Information Computational Center) as a FOR-TRAN 77 source code. It may be suitable for either parametric preliminary design or detailed final design, e.g. a manned flight or radiation-sensitive component configuration design. It needs some debugs, recompiling and a tedious work to make geometrical quadric surfaces for actual spacecraft configuration, and has poor documentation. It is recommend to vist RSICC homepage and GEANT4/SSAT homepage.

• 한국산학기술학회논문지
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• 제22권3호
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• pp.777-783
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• 2021

항공기는 기동 중 다양한 진동의 영향을 받게 된다. 이러한 진동들은 상황에 따라서는 항공기 생존에 치명적인 영향을 미칠 수 있으므로 항공기에 적용되는 구성품들은 랜덤 진동해석을 통해 다양한 진동 조건에 대한 안전성이 입증되어야 한다. 본 연구에서는 상용 소프트웨어인 MSC.Random을 사용하여 랜덤진동 조건에서 군용항공기 외부연료탱크와 파일런에 대한 구조 강건성을 평가하였다. 랜덤 진동해석은 경계조건 지점에 단위하중을 부과하여 주파수 응답해석을 수행한 후 파워 스펙트럼 밀도 프로파일로 가진하게 되는데, 이 과정에서 필요한 모드 데이타는 모달해석 방법을 통해 추출하였다. 그리고, 랜덤진동 조건으로 미국 국방환경규격에서 규정하고 있는 랜덤 진동 프로파일을 적용하였고, G 단위로 주어진 파워 스펙트럼 밀도 프로파일을 중력가속도 단위로 변환하여 사용하였다. 수치해석 결과로, x축, y축 및 z축 방향에서의 랜덤 가진에 대해 수치해석 모델을 구성하는 빔 요소, 쉘 요소 그리고 솔리드 요소의 안전여유를 파악하여 본 논문에서 다루고 있는 군용 항공기에 장착되는 외부연료탱크와 파일런의 구조 강건성을 평가하였다.

• Parasites, Hosts and Diseases
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• 제29권3호
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• pp.245-258
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• 1991

요꼬가와흠흡에 감염된 숙주에서 항체생성을 유도하는 물질의 충체 래에 분포하고 있는 부위를 확인하기 위하여 대조군의 실험동물 IgG와 요꼬가와흡충에 감염된 실험고양이의 특이항체 IgG를 요꼬가와흡충 성충조직에 반응시키고 면역황금표식법을 이용하여 전자현미경으로 관찰하여 다음과 같은 결과를 얻었다. 대조군의 IgG를 반응시킨 조직항원에는 환금입자의 표지가 관찰되지 않았으나 표피층은 표피세포들의 원형질돌기들이 표피합포체를 구성하고 있었으며 기저층은 분명하게 구별되고 경육층도 잘 발달되어 있었다. 난황세포는 크기가 다양한 분필과립들을 포함하고 있었으며 조면소포체가 특히 발달되어 있었다. 맹관의 막구조물은 잘 발달되었으며 장상피 합포체도 잘 발달되어 있었다. 저정낭에는 정자가 전자밀도가 릎은 두부와 미세소관이 잘 발달한 미부로 구성되어 있었으며, 배설낭은 배설낭 상피에 막구조물이 관찰되었고 충란은 전자밀도가 높은 난각이 관찰되었다. 요꼬가와흡충에 감염된 실험동물의 IgG를 반응시킨 조직항원의 표피충에는 표피합포체와 표피세포의 세포질에 황금입자가 높은 밀도로 표지되어 강한 항원성을 나타내었다. 그리고 난황세포의 분필과립과 맹관 막구조물과 맹관 내강에도 환금입자가 높은 밀도로 관찰되어 항원성이 강한 것으로 생각되었다. 저정낭의 정자와 배설낭의 막구조물에는 적은 수의 황금입자가 표지되어 항원성이 미약한 것으로 생각되었으나, 자궁의 충란 난각에는 황금입자가 다소 표지되어 항원성물질이 존재하는 것으로 생각되었다. 이상의 결과로 요꼬가와홉충에 감염된 실험 고양이는 요꼬가와흡충의 표피합포체와 표피세포에서 생성된 물질과 난황세포에서 생성된 물질에 의하여 면역항체가 형성되며 일부는 맹관 내용물에 의하여 면역항체가 유도되는 것으로 생각되었다.는 69.7%의 같은 비율로 높았다. 이상으로 요충 감염은 아직까지 높은 상태임을 알았고 예방을 위한 집단 구충에는 전 집단에 대한 3회 이상의 반복구충이 효과적이었다. gas layers is also made. Low resolution spectral intensities at the boundary are obtained for uniform, parabolic and boundary layer type temeprature profiles using the obtained for uniform, parabolic and boundary layer type temperature profiles using the obtained WSGGM's with 9 gray gases. The results are compared with the narrow band spectral intensities as obtained by a narrow band model-based code with the Curtis-Godson approximation. Good agreement is found between them. Local heat source strength and total wall heat flux are also compared for the cases of Kim et al, which again gives promising agreement.면적 306~453$\textrm{cm}^2$, 유색계의 경우 수당면적 340~453$\textrm{cm}^2$ 일 때 경제능력을 제대로 발휘할 수 있고 경제성이 있는 것으로 나타났다. 첨가구가 높은 경향이 있었다8.4%. 79.7% 그리고