• 한국재료학회지
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• 제9권8호
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• pp.837-842
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• 1999

Ta/TaN 다층피막구조는 경도는 떨어지지만 연성이 큰 Ta 막과 취성을 가지며 경도가 높은 TaN 막을 교대로 반복하여 만든 다층구조로서 경도와 연성의 장점이 잘 조화되어 높은 인성을 나타낼 것으로 기대된다. 본 연구에서는 고속도강 기판위에 Ta/TaN 복합다층피막과 compositional gradient Ta-TaN 막을 각각 반응성 스퍼터링에 의하여 증착하고 열처리에 따른 경도 및 접착성을 조사하였다. $N_2$/Ar 유량비가 0.4일 때 결정성이 가장 우수한 TaN 막이 얻어지며, Ta/TaN 복합다층피막의 경도 및 스크래치 테스트 결과도 가장 우수하였다. 또한 Ta/TaN 복합다층피막 증착후의 어닐링 처리 시 어닐링 온도가 증가할수록 피막의 경도와 접착성이 악화되었으며, compositional modulation wavelength가 감소함에 따라 Ta/TaN 복합다층피막의 경도는 증가하지만 접착성은 wavelength에 대한 의존성이 약하게 나타났다. 그리고 compositional gradient Ta-TaN 막 증착후의 어닐링 처리 시 경도와 스크래치 테스트 값은 각각 20$0^{\circ}C$와 40$0^{\circ}C$에서 최대값을 나타내었다.

• 한국환경과학회지
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• 제15권5호
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• pp.397-403
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• 2006

Compositional characteristics and origin of polycyclic aromatic hydrocarbons(PAHs), which should be strongly regulated for environmental protection in the crude oils and petroleum products, have been investigated by gas chromatography-mass spectrometry(GC/MS). In the crude oils analyzed, two-rings compound(naphthalene) of PAHs was detected around $72.3\sim93.5%$, but five- or six-rings compound of PAHs was not detected. In the crude oils analyzed, the molecular ratio indices of Phe/Ant(phenanthrene/anthracene)>15, Fla/Pyr(fluoranthene/pyrene)<1, BaA/Chr(benzo (a)anthracene/chrysene)$\leq0.4$ could be effectively applied, and we found that the origin of PAHs was petrogenic sources. Total PAHs concentrations in the crude oils were increased with increasing API gravity and with decreasing sulfur contents of the analyzed crude oils. Five- or six-rings compound of PAHs were not included in ail petroleum products except bunker-C. Furthermore, the molecular ratio indices of Phe/Ant(phenanthrene/anthracene) vs. Fla/Pyr(fluoranthene/pyrene) could be effectively applied as the standard for the PAHs contamination criterion at the other Korean areas.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.367-367
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• 2011

CIGS solar cell with copper, indium, gallium and selenium is a second generation solar cells for the lowering of the manufacturing cost. The relative ratio of the four elements is one of the most important measurement issues because the photovoltaic property of CIGS solar cell depends on the crystalline structure of the CIGS layer. However, there is no useful analysis method for the composition of the CIGS layer. Recently, AES depth profiling analysis of CIGS films has been studied with a reference material certified by inductively coupled plasma optical emission spectroscopy. However, there are some problems in AES depth profiling analysis of CIGS films. In this study, the in-depth profiling analysis was investigated by secondary ion mass spectrometry (SIMS) depth profiling analysis. We will present the compositional depth profiling of CIGS films by SIMS and its applications for the development of CIGS solar cells with high efficiency.

• Elastomers and Composites
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• 제45권2호
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• pp.122-128
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• 2010

소수성실리카를 안정제로 하는 현탁중합반응법을 이용하여 합성한 스티렌(St)/부틸메타크릴레이트(BMA) 공중합체 (co-PSB) 입자의 전단점도를 모세관 레오미터 (capillary rheometer)를 이용하여 $170^{\circ}C$에서 측정하였다. co-PSB 입자의 전단점도는 중량평균분자량이 74,800 g/mol 이하인 경우 낮은 전단속도에서는 뉴톤거동을 보였다. 중량평균분자량이 136,800 g/mol을 초과하면서 전단점도는 전단속도의 전 영역에 걸쳐 감소하였고 전단속도에 대한 기울기의 절대값은 분자량의 증가와 함께 증가하였다. St/BMA의 구성비가 7/3, 5/5 및 3/7의 co-PSB 입자는 유사한 분자량을 나타내었지만 BMA의 구성비가 증가하면서 유리전이온도와 전단점도는 감소하였다. St/BMA의 구성비가 1/9 인 co-PSB의 경우 유리전이온도는 더욱 감소하였으나 초기 전단점도는 크게 증가하였다. 카본블랙을 함유하는 co-PSB 복합체 입자의 전단점도는 카본블랙의 증가에 따라 증가하였으나, 카본블랙의 농도에 따른 전단점도의 변화는 분자량 및/혹은 구성비의 변화 효과에 비교하여 미약하였다.

• 한국수산과학회지
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• 제30권4호
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• pp.679-686
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• 1997

본 연구조사는 동해남부 대마난류계에서의 PCBs의 분포특성을 파악하기 위하여 1996년 8월과 10월에 걸쳐 5개 정점을 선정하여 각 정점의 수심별의 수온, 염분 및 용존산소를 측정하여 수괴 분석을 실시하였으며, 또한, 각 정점별, 수심별의 PCBs의 분석을 실시하였다. 수괴의 분포특성을 조사한 결과 수온 및 염분약층은 수심 30m부분에 존재하고 있었으며, 대마난류 중층수는 30m이하로 간주되었으며, 대마난류의 표층수는 한국근해에서 대마도쪽으로 확장되는 양상을 보였다. PCBs의 분석결과 표층수는 8월의 경우 대마도쪽으로 갈수록 농도가 약간 낮아지는 경향을 보이다가, 대마도쪽에서 다시 약간의 증가경향이 관찰되었다. 표층 해수중에서의 PCBs의 평균농도는 $0.29\;ng/\ell$정도 였으며, 중층에서의 평균농도는 $0.31\;ng/\ell$정도로 표층에 비교하여 중층에서의 농도가 약간 증가하는 것으로 나타났다. 해수중 PCBs의 농도는 부유물질의 농도변화 경향과 유사성을 나타났으며, 농도의 수평 및 연직변화는 그다지 크게 나타나지 않아 비교적 균일한 농도분포를 나타내고 있었다. 해수의 수심별 PCBs의 상대농도 조성비는 표층에서 Di- 및 Tri-PCBs의 비율이 높았지만, 심층으로 갈수록 Peta-PCBs의 상대농도 조성비율이 높은 것으로 나타나, 수심의 변화에 따른 PCBs의 구성비와 소실에 차이가 있는 것으로 사료된다.

• 한국세라믹학회지
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• 제50권2호
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• pp.134-141
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• 2013

Pond ash produced from Seochun Power Station was quantitatively characterized to manufacture geopolymers with a range of Si/Al compositional ratios. Mix consistency was kept nearly constant for comparing the compressive strengths of geopolymers. The amorphous composition of coal ash was determined using XRF and quantitative X-ray diffraction. Different mix compositions were used in order to achieve Si/Al ratios of 2.0, 2.5 and 3.0 in the geopolymer binder. Geopolymers synthesized from coal ash with a Si/Al ratio of 3.0 exhibited the highest compressive strength in this study. It was found that geopolymers activated with aluminate produced different microstructure from that of geopolymers activated with silicate. High silica in alkali activators produced the fine-grained microstructure of geopolymer gel. It was also found that high compressive strength was related to low porosity and a dense, connected microstructure. The outcome of the reported experiment indicates that quantitative formulation method made it possible to choose suitable activators for achieving targeted compositions of geopolymers and to avoid efflorescence.

• 한국세라믹학회지
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• 제32권9호
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• pp.1009-1018
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• 1995

(Ti.Si)C composite powders were synthesized by SHS method using microwave energy. Compositional and structural characterization of the powder were carried out by using scanning electron microscopy and X-ray diffraction. The average particle size of the synthesized (Ti.Si)C composite powders was smaller than that of the starting materials. From the results of the temperature profile, combustion temperature and velocity were decreased with increasing Si molar ratio. With increasing C molar ratio combustion temperature and velocity did not change. (Ti.Si)C composite was sintered at 185$0^{\circ}C$ for 60 min by using hot-pressing with 30 MPa. The best properties were obtained from the sintered specimen whose composition was 1 : 1 : 1.9 molar ratio of Ti : Si : C. The sintering density, flexural strength and vickers hardness of the sintered body were 4.71 g/㎤, 423 MPa and 21 GPa, respectively.

• 한국세라믹학회지
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• 제34권10호
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• pp.1003-1008
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• 1997

The (La, Sr)MnO3 powder used as air-electrode material of Solid Oxide Cell (SOFC) was synthesized by Modified-GNP(Modified-Glycine Nitrate Process). The powders were prepared using oxide and carbonate stable in atmosphere and nitric acid was used as a solvent of starting material as well as an oxidant for combustion. The (La, Sr)MnO3 powders were synthesized with 0.5, 1, 2, 3, 4 of glycine/cation molar ratio. The ICP (Inductively Coupled Plasma Mass Spectrometer) result represented compositional equality between synthesized and desired powders. In case of 2 molar ratio, the as-synthesized powder showed perovskite phase and specific surface area were 19 $m^2$/g. After calcination of 85$0^{\circ}C$, the calcined powder except 0.5, 1 molar ratio of glycine to cation showed perovskite phase.

• 대한영양사협회학술지
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• 제16권4호
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• pp.341-352
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• 2010

The aim of this study was to use purple sweet potato powder to develop a recipe for a nutritional cookie with an optimal composition of ingredients and texture, in order to acquire strong preference responses by all age groups in sensory tests. Wheat flour was partially substituted with purple sweet potato powder to reduce the wheat flour content of the cookies. Measurements were made and analyzed according to the Response Surface Methodology technique, which showed 16 experimental points including 3 replicates for the purple sweet potato powder, sugar, and butter. The compositional and functional properties of the sample were measured, and the values obtained were applied to a mathematical model. A canonical form and perturbation plot showed the influence of each ingredient on the final product mixture. The results of sensory evaluations showed very significant values for flavor (P<0.0071), texture (P<0.0306), taste (P<0.0190), and overall quality (P<0.0142). Instrumental analysis showed significant values for hardness (P<0.0027), yellowness (P<0.0061) and spread ratio (P<0.0001). The optimal compositional ratios were determined to be 21.75 g for the purple sweet potato powder, 37.05 g for the sugar, and 60.59 g for the butter.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.450-454
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• 2018

In recent years, thermal insulation coating technology for automotive engine parts has received significant attention as a means of improving the thermal efficiency of automotive engines. One of the characteristics of thermal insulation coatings is their low thermal conductivity, and, materials such as YSZ (Yttria-stabilized zirconia), which have low thermal conductivity, are used for this purpose. This research presents a study of the changes in the microstructure and thermal conductivity of $8YSZ/SiO_2$ multi compositional thermal insulation coating for different compositions, and particle size distributions of suspension, when it is subjected to suspension plasma spraying. To obtain a porous coating structure, the mixing ratio of 8YSZ and $SiO_2$ particles and the particle sizes of the $SiO_2$ were changed. The microstructure, phase formation behavior, porosity and thermal conductivity of the coatings were analyzed. The porosities were found to be 1.2-32.1%, and the thermal conductivities of the coatings were 0.797-0.369 W/mK. The results of the study showed that the microstructures of the coatings were strongly influenced by the particle size distributions, and that the thermal conductivities of the coatings were greatly impacted by the microstructures of the coatings.