• 보존과학회지
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• 제6권1호
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• pp.3-14
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• 1997

15세기 말과 16세기 초에 철화분청을 생산했던 곳으로 잘 알려진 공주 학봉리에서 수습된 12 도편의 분청사기를 과학적으로 분석하였다. 태토와 유약의 성분은 각각 X선 형광분석기와 전자현미분석장치로 분석하였고, 미세구조분석은 광학현미경, 편광현미경, 전자현미분석장치, 그리고 X선회절분석기를 이용하였다. 태토와 유약의 성분은 학봉리에서 지리적으로 가까운 곳에 위치한 보령 용수리분청과 비교하여 통계분석을 하였으며, SPSS프로그램을 사용하였다 태토는 보령 송수리 분청에 비해 실리카와 용융제는 높게 나타났으나, 알루미나는 낮은 수치를 보였고, 유약은 실리카, 소다. 철산화물은 높은 반면, 알루미나와 칼슘산화물의 양은 낮게 나타났다. 학봉리 분청 자체도 두 그룹으로 나뉘었다. 유약은 라임계열이었으며, 태토내에는 석영, 둘레가 일부 녹은 큰 장석덩어리, 사장석, 흑운모와 철산화물과 같은 결정들이 많이 남아있음을 관찰할 수 있었다. 이러한 미세구조로 보아 원료의 수비상태가 좋지 않았고, 번조온도도 비교적 낮았음을 예측할 수 있다. 철화안료의 원료는 성분과 X선 회절분석에 의해 Mg/Fe/Al 스피넬로 확인되었다.

• Restorative Dentistry and Endodontics
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• 제40권1호
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• pp.50-57
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• 2015

Objectives: The usage of medicinal plants as natural antimicrobial agents has grown in many fields including dental medicine. The aim of this in vitro study was three-fold: (i) to determine the chemical compositions of the Ferula gummosa essential oil (FGEO), (ii) to compare the antimicrobial efficacy of the oil with sodium hypochlorite (NaOCl) and chlorhexidine (CHX), (iii) to assess the toxic behavior of FGEO in different concentrations compared to 5% NaOCl and 0.2% CHX. Materials and Methods: Gas chromatography/mass spectrometry (GC/MS) was used to determine the chemical compositions of the oil. The disk diffusion method and a broth micro-dilution susceptibility assay were exploited to assess the antimicrobial efficacy against Enterococcus faecalis, Staphylococcus aureus, Streptococcus mitis, and Candida albicans. The cytocompatibility of the FGEO was assessed on L929 fibroblasts, and compared to that of NaOCl and CHX. Results: Twenty-seven constituents were recognized in FGEO. The major component of the oil was ${\beta}$-pinene (51.83%). All three irrigants significantly inhibited the growth of all examined microorganisms compared to the negative control group. FGEO at $50{\mu}g/mL$ was effective in lower concentration against Enterococcus faecalis than 5% NaOCl and 0.2% CHX, and was also more potent than 0.2% CHX against Candida albicans and Staphylococcus aureus. FGEO was a cytocompatible solution, and had significantly lower toxicity compared to 5% NaOCl and 0.2% CHX. Conclusions: FGEO showed a promising biological potency as a root canal disinfectant. More investigations are required on the effectiveness of this oil on intracanal bacterial biofilms.

• 한국인터넷방송통신학회논문지
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• 제21권5호
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• pp.127-134
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• 2021

최근 빅데이터 산업의 확대로 고품질의 데이터를 확보하는 것이 중요한 이슈로 떠오르고 있다. 고품질의 데이터를 확보하기 위해서는 데이터에 품질에 대한 정확한 평가가 선행되어야 한다. 데이터의 품질은 데이터에 대한 통계와 같은 메타정보를 통해 평가할 수 있는데 이러한 메타정보를 자동으로 추출하는 기능을 데이터 프로파일링이라고 하다. 지금까지 데이터 프로파일링 소프트웨어는 기존의 데이터 품질 또는 시각화 관련 소프트웨어의 부품이나 추가적인 서비스로 제공되는 것이 일반적이었다. 따라서 프로파일링이 요구되는 다양한 환경에서 직접적으로 사용하기에는 적합하지 않았다. 본 논문에서는 이를 해결하기 위해 마이크로 서비스 아키텍처를 적용하여 다양한 환경에서 서비스가 가능한 데이터 프로파일링 소프트웨어의 개발 결과를 제시한다. 개발된 데이터 프로파일러는 restful API를 통해 데이터의 메타정보에 대한 요청과 응답을 제공하여 사용하기 쉬운 서비스를 제공한다. 또한, 특정 환경에 종속되지 않고 다양한 빅데이터 플랫폼이나 데이터 분석 도구들과 원활한 연계가 가능하다는 장점이 있다.

• Mass Spectrometry Letters
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• 제10권1호
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• pp.11-17
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• 2019

Drosophila melanogaster (fruits fly) is a representative model system widely used in biological studies because its brain function and basic cellular processes are similar to human beings. The whole head of the fly is often used to obtain the key function in brain-related diseases like degenerative brain diseases; however the biomolecular distribution of the head may be slightly different from that of a brain. Herein, lipid profiles of the head and dissected brain samples of Drosophila were studied using electrospray ionization-mass spectrometry (ESI-MS). According to the sample types, the detection of phospholipid ions was suppressed by triacylglycerol (TAG), or the specific phospholipid signals that are absent in the mass spectrum were measured. The lipid distribution was found to be different in the wild-type and the microRNA-14 deficiency model ($miR-14{\Delta}^1$) with abnormal lipid metabolism. A few phospholipids were also profiled by comparison of the head and the brain in two fly model systems. The mass spectra showed that the phospholipid distributions in the $miR-14{\Delta}^1$ model and the wild-type were different, and principal component analysis revealed a correlation between some phospholipids (phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS)) in $miR-14{\Delta}^1$. The overall results suggested that brain-related lipids should be profiled using fly samples after dissection for more accurate analysis.

• 대한금속재료학회지
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• 제47권12호
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• pp.811-818
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• 2009

In order to meet increasingly complex and rigorous technical specifications, extensive effort has been devoted to fabricate clad materials with multi-layered metal plates. In this study, novel stainless steel/aluminum/copper (STS/Al/Cu) three-ply clad materials were fabricated by a hot rolling process for cookware applications. The effect of the testing temperature on the mechanical properties of the clad materials and on each component metal was investigated during the tensile tests. The interface properties of the clad materials were also examined by optical microscopy (OM) and an electron probe micro-analyzer (EPMA). The best mechanical and interfacial properties for a warm working process were found in a sample annealed at a temperature of $300^{\circ}C$. For the sample annealed at $400^{\circ}C$, the results of the tensile test indicated that interface delamination occurred only in the region of the Al/Cu interfaces. This was due to the formation of the thick and brittle intermetallic compound of $Al_2Cu$ in the Al/Cu interface. In contrast, no interface delamination was observed in the STS/Al interface, most likely due to its strong bond strength.

• Design & Manufacturing
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• 제14권4호
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• pp.71-77
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• 2020

Various manufacturing technologies, including over-molding and insert-injection molding, are used to produce hybrid plastics and metals. However, there are disadvantages to these technologies, as they require several steps in manufacturing and are limited to what can be reasonably achieved within the complexities of part geometry. This study aims to determine a practical approach for producing metal/plastic hybrid components by combining plastic injection molding and metal die casting to create a new hybrid metal/plastic molding process. The integrated metal/plastic hybrid injection molding process developed in this study uses the proven method of multi-component technology as a basis to combine plastic injection molding with metal die casting into one integrated process. In this study, the electrical conductivity and ampacity were verified to qualify the new process for the production of parts used in electronic devices. The electrical conductivity was measured, contacting both sides of the test sample with constant pressure, and the resistivity was measured using a micro ohmmeter. Also, the specific conductivity was subsequently calculated from the resistivity and contact surface of the conductor path. The ampacity defines the maximum amount of current a conductive path can carry before sustaining immediate or progressive deterioration. The manufactured hybrid multi-components were loaded with increasing currents, while the temperature was recorded with an infrared camera. To compare the measured infrared images, an electro-thermal simulation was conducted using commercial CAE software to predict the maximum temperature of the power loaded parts. Overall, during the injection molding process, it was demonstrated that multifunctional parts can be produced for electric and electronic applications.

• Tribology and Lubricants
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• 제38권5호
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• pp.185-190
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• 2022

Among the operating limits of a heat pipe, the capillary limit is significantly affected by the characteristics of the wick, which is determined by the capillary performance. The major parameters for determining capillary performance are the maximum capillary pressure and the spreading characteristics that can be expected through the wick. A well-designed wick structure improves capillary performance and helps improve the stability of the heat pipe by enhancing the capillary limit. The capillary performance can be improved by forming a porous microstructure on the surface of the wick structure through surface modification techniques. In this study, a microstructure is formed on the surface of the wick by using a surface modification method (i.e., an electrochemical etching process). In the experiment, specimens are prepared using stainless-steel screen mesh wicks with various fabrication conditions. In addition, the spreading and capillary rise performances are observed with low-surface-tension fluid to quantify the capillary performance. In the experiments, the capillary performance, such as spreading characteristics, maximum capillary pressure, and capillary rise rate, improves in the specimens with microstructures formed through surface modification compared with the specimens without microstructures on the surface. The improved capillary performance can have a positive effect on the capillary limit of the heat pipe. It is believed that the surface microstructures can enhance the operational stability of heat pipes.

• Fisheries and Aquatic Sciences
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• 제26권2호
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• pp.145-157
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• 2023

Surimi has been traditionally used as the main ingredient in gelling foods, such as imitation crab sticks. However, it can also be used to manufacture snacks without gelling properties. To assess the properties of surimi as a snack ingredient, we prepared fried fish snacks with different surimi grades of Alaska pollack (AP) and threadfin bream (TB) and evaluated their quality characteristics. AP had significantly higher protein and gel strength values than TB did. Regarding color, TB showed significantly lower lightness (L) values and higher redness (a) and yellowness (b) values than AP did, consistent with the appearance of a brown color. TB had significantly lower hardness values, higher thickness expansion, and higher oil content than AP did. Hardness was found to be positively correlated with gel strength and negatively correlated with oil content. In the micro-structure images, more blistering was formed in TB, indicating higher expansion and crispiness. In the sensory evaluation, TB showed higher overall sensory acceptance than AP did, which is the result of its high color content, crispiness, taste, and aroma. Principal component analysis of the electronic nose and tongue revealed that the samples were clearly separated. In particular, TB had more aromatic components than AP in the electronic tongue. Our findings indicate that gel strength, which determines the quality properties of surimi, does not need to be considered in snack manufacturing. In fact, surimi with low gel strength is a more suitable ingredient for snack manufacturing.

• Computers and Concrete
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• 제32권1호
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• pp.61-74
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• 2023

This article investigates the wave propagation analysis of the imperfect functionally graded (FG) sandwich plates based on a novel simple four-variable integral quasi-3D higher-order shear deformation theory (HSDT). The thickness stretching effect is considered in the transverse displacement component. The presented formulation ensures a parabolic variation of the transverse shear stresses with zero-stresses at the top and the bottom surfaces without requiring any shear correction factors. The studied sandwich plates can be used in several sectors as areas of aircraft, construction, naval/marine, aerospace and wind energy systems, the sandwich structure is composed from three layers (two FG face sheets and isotropic core). The material properties in the FG faces sheet are computed according to a modified power law function with considering the porosity which may appear during the manufacturing process in the form of micro-voids in the layer body. The Hamilton principle is utilized to determine the four governing differential equations for wave propagation in FG plates which is reduced in terms of computation time and cost compared to the other conventional quasi-3D models. An eigenvalue equation is formulated for the analytical solution using a generalized displacements' solution form for wave propagation. The effects of porosity, temperature, moisture concentration, core thickness, and the material exponent on the plates' dispersion relations are examined by considering the thickness stretching influence.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.93-98
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• 2023

As semiconductor devices become highly integrated and process difficulty increases, the need for highly sensitive sensors that can detect micro leaks is increasing. However, the noise contained in the CCD sensor itself acts as an obstacle to detecting fine leaks. In this study, integration time was changed for each condition, the sensor was cooled to 0℃, and the dark voltage level was measured to confirm through experiment the characteristics of the temporal noise included in the CCD sensor, a component of OES (Optical Emission Spectroscopy). When integration time was reduced from 30msec to 10msec, the dark voltage level decreased by about 20.5 % from an average of 151.5mV to 120.5mV. In the case of cooling device, Peltier elements were selected because of their simple structure and small size. During temperature cooling, the target temperature was controlled to within ±0.5℃ through PID control. When cooled from 20℃ to 0℃ using this cooling device, it was confirmed that the dark voltage level decreased by about 7% from an average of 147.0mV to 137.0mV.