• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.353-353
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• 2008

Carbon nanotubes (CNTs) are attractive for field emitter because of their outstanding electrical, mechanical, and chemical properties. Several applications using CNTs as field emitters have been demonstrated such as field emission display (FED), backlight unit (BLU), and X-ray source. In this study, we fabricated a CNT cathode using transparent ultra-thin CNT film. First, CNT aqueous solution was prepared by ultrasonically dispersing purified single-walled carbon nanotubes (SWCNTs) in deionized water with sodium dodecyl sulfate (SDS). To obtain the CNT film, the CNT solution in a milliliter or even several tens of micro-litters was deposited onto a porous alumina membrane through vacuum filtration process. Thereafter, the alumina membrane was solvated by the 3 M NaOH solution and the floating CNT film was easily transferred to an indium-tin-oxide (ITO) glass substrate of $0.5\times0.5cm^2$ with a film mask. The transmittance of as-prepared ultra-thin CNT films measured by UV-Vis spectrophotometer was 68~97%, depending on the amount of CNTs dispersed in an aqueous solution. Roller activation, which is a essential process to improve the field emission characteristics of CNT films, increased the UV-Vis transmittance up to 93~98%. This study presents SEM morphology of CNT emitters and their field emission properties according to the concentration of CNTs in an aqueous solutions. Since the ultra-thin CNT emitters prepared from the solutions show a high peak current density of field emission comparable to that of the paste-base CNT emitters and do not contain outgassing sources such as organic binders, they are considered to be very promising for small-size-but-high-end applications including X-ray sources and microwave power amplifiers.

• 한국의류산업학회지
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• 제16권3호
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• pp.492-498
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• 2014

Lotus(Nelumbo nucifera gaertn) is intimate plant to many people that it has clean and noble characteristics despite growth in the mud. Especially Lotus seedpods, byproduct of lotus, are rich in oligometric procyanidins and could be a new source of procyanidins. Procyanidins, also known as condensed tannins, are a class of polyphenols. In other words lotus seedpod contains plenty of tannins. Commonly tannins colorants could increase adsorption and fastness properties in fabric dyeing. This study was made to investigate colorants characteristics of lotus seedpod and various colorfastness properties of dyed silk fabrics. The wavelength of maximum absorption of lotus seedpod solution appeared at 273.5 nm from UV-vis spectrophotometer. From the results of FT-IR spectra measurements, IR absorption band of lotus seedpod colorants appeared at $3415cm^{-1}$, $2900cm^{-1}$ and $1620cm^{-1}$ by tannin structure. And tannin ingredient contents was the highest at pH 9 and flavonoid at pH 11. Lotus seedpod colorants showed relatively good affinity at pH 3 on silk fabrics and optimum dyeing temperature and time for silk was for 50 min, at $80^{\circ}C$. K/s of Light fastness according to different washing method was the highest at process including ironing and ${\Delta}E$ was the lowest. All of fastness(Light rubbing laundering perspiration dry cleaning) showed excellent results over 4 or 4-5 grades.

• 폴리머
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• 제28권2호
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• pp.103-110
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• 2004

토코페롤을 함유하는 폴리($\varepsilon$-카프로락톤)(PCL) 마이크로캡슐은 액중건조법에 의하여 제조하였고, 제조 조건에 따른 마이크로캡슐의 특성과 PCL 필름을 사용하여 PCL의 분해거동을 측정하였다 제조된 마이크로캡슐의 크기 및 형태와 구조적 특성은 각각 SEM과 XRD를 이용하여 관찰하였다. 또한, 접촉각 측정을 통하여 심물질의 농도에 따른 마이크로캡슐의 표면자유에너지를 측정하였다. 실험결과, 마이크로캡슐은 유화제로 폴리(비닐 알코올)을 사용한 경우 안정된 구형의 마이크로캡슐이 형성되었고, 마이크로캡슐의 표면자유에너지와 PCL의 결정성은 감소하고, PCL 필름은 악 21일 후 분해가 시작되었다. 토코페롤의 방출특성은 UV/vis.에 의하여 측정하였으며, 마이크로캡슐의 방출속도는 교반속도의 증가와 함께 증가하였다. 이는 교반속도의 증가와 함께 감소된 마이크로캡슐 입자 크기에 의한 방출용액과 마이크로캡슐 사이의 계면의 증가에 의한 것으로 판단된다.

• 분석과학
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• 제23권3호
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• pp.225-232
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• 2010

본 연구에서 종래의 졸-겔법을 사용하여 Fe-ACF/$TiO_2$ 광촉매 복합체를 제조하였고, 이들 광촉매의 분해능은 메틸렌블루 (MB) 용액의 분해에 의하여 나타내었다. 제조된 이들 복합체에 대한 입자크기, 표면구조, 결정상 및 원소분석을 BET, SEM, XRD 및 EDX에 의하여 각각 특성화 하였다. 가시광선 조건에서 분해된 MB 농도에 대한 스펙트라는 UV/Vis 분광기에 의하여 얻어 졌다. 이와 같이 얻어진 스펙트라는 MB의 제거된 농도로부터 광촉매 활성을 입증하였다. 이들 광촉매 활성은 가시광선 조건에서 복합체 광촉매 내에 존재하는 ACF, $TiO_2$ 및 Fe 사이에 강력한 시너지 반응에 의해 유도된 것으로 여겨진다.

• 공업화학
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• 제28권1호
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• pp.95-100
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• 2017

본 연구에서는 Pigment Red 57:1의 다양한 합성 방법에 따른 입자 거동 및 그의 따른 색상, 점도, 및 분광학적 특성 등을 분석하기 위하여, 합성 시간, pH, 유도체 함량 및 결정화 온도 등의 변수를 이용하여 시료를 합성한 후 그 분산액을 제조하였으며, 그에 따른 특성을 비교 분석하였다. 시료들의 특성은 푸리에 적외선 분광기, UV-Vis 분광기, 입도 분석기, 색차계, X선 회절 분석계 등을 이용하여 비교 분석하였다. 그 결과 합성 조건 조절을 통하여 안료 입자의 크기를 다양하게 조절하는 것이 가능하였다.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.453-464
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• 2014

The current research was focused on the extracellular biosynthesis of bactericidal silver nanoparticles (AgNPs) using cell-free supernatant of a local isolate previously identified as a novel Streptomyces aegyptia NEAE 102. The biosynthesis of silver nanoparticles by Streptomyces aegyptia NEAE 102 was quite fast and required far less time than previously published strains. The produced particles showed a single surface plasmon resonance peak at 400 nm by UV-Vis spectroscopy, which confirmed the presence of AgNPs. Response surface methodology was chosen to evaluate the effects of four process variables ($AgNO_3$ concentration, incubation period, pH levels, and inoculum size) on the biosynthesis of silver nanoparticles by Streptomyces aegyptia NEAE 102. Statistical analysis of the results showed that the linear and quadratic effects of incubation period, initial pH, and inoculum size had a significant effect (p < 0.05) on the biosynthesis of silver nanoparticles by Streptomyces aegyptia NEAE 102. The maximum silver nanoparticles biosynthesis (2.5 OD, at 400 nm ) was achieved in runs number 5 and 14 under the conditions of 1 mM $AgNO_3$ (1-1.5% (v/v)), incubation period (72-96 h), initial pH (9-10), and inoculum size (2-4% (v/v)). An overall 4-fold increase in AgNPs biosynthesis was obtained as compared with that of unoptimized conditions. The biosynthesized silver nanoparticles were characterized using UV-VIS spectrophotometer and Fourier transform infrared spectroscopy analysis, in addition to antimicrobial properties. The biosynthesized AgNPs significantly inhibited the growth of medically important pathogenic gram-positive (Staphylococcus aureus) and gram-negative bacteria (Pseudomonas aeruginosa) and yeast (Candida albicans).

• 한국결정성장학회지
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• 제20권4호
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• pp.159-163
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• 2010

스컬용융법으로 큐빅지르코니아(YSZ) 단결정들($ZrO_2:Y_2O_3:Co_3O_4:CeO_2$=64:36:0.5:0~0.3mol%)을 성장시켜 $N_2$ 분위기 $1200^{\circ}C$에서 3시간 동안 열처리 하였다. 갈색의 단결정들은 각각 녹색 또는 청색으로 변화되었다. 열처리 전 후의 YSZ 단결정들은 직경 7, 두께 2 mm의 웨이퍼 또는 직경 12 mm의 라운드브릴리언트 컷으로 연마 하였다. 각 시편의 광학적 또는 구조적 특성은 UV-VIS 분광광도계와 XRD(X-ray diffraction)로 분석하였으며, $Ce^{3+}(^2F_{5/2},\;_{7/2}(4f){\rightarrow}^2T_g(5d^1))$, $Co^{2+}(^4A_2(^4F){\rightarrow}^4T_1(^4F)$ 또는 $^4T_1(^4P)$) 및 $Co^{3+}$에 의한 흡수, 이온화에너지 및 격자상수 변화를 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3761-3766
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• 2012

$Ag_2Se$-Graphene/$TiO_2$ composite was synthesized by a facile sonochemical method. The as-prepared products were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectrophotometer. During the reaction, both of the reduction of graphene oxide and loading of $Ag_2Se$ and $TiO_2$ particles were achieved. The as-prepared $Ag_2Se$-Graphene/$TiO_2$ composites possessed great adsorptivity of dyes, extended light absorption range, and efficient charge separation properties simultaneously. Hence, in the photodegradation of rhodamine B (Rh.B), a significant enhancement in the reaction rate was observed with $Ag_2Se$-Graphene/$TiO_2$ composites, compared to the pure $TiO_2$. The high activity can be attributed to the synergetic effects of high charge mobility, and red shift in absorption edge of $Ag_2Se$-Graphene/$TiO_2$ composites.

• Elastomers and Composites
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• 제39권2호
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• pp.153-160
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• 2004

풀러렌($C_{70}$)을 3-picoline N-oxide, pyridine N-oxide hydrate, quinoline N-oxide, isoquinolne N-oxide의 여러가지 아민 N-옥시드를 사용하여 $25{\sim}43^{\circ}C$, 초음파 조건에서 반응시켜 풀러렌 산화물을 합성 하였다. 동일한 초음파 조건에서 여러가지 아민 N-옥시드에 대한 풀러렌 ($C_{70}$)의 반응성은 3-picoline N-oxide : pyridine N-oxide hydrate : quinoline N-oxide : isoquinoline N-oxide 처럼 동일하게 나타났다. MALDI -TOF MS, UV-vis 그리고 HPLC를 사용하여 생성된 풀러렌 산화물을 분석한 결과 [$C_{70}(O)n$] (n=1) 임을 알 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.374.2-374.2
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• 2016

Volatile organic compounds (VOCs) in the atmosphere are harmful materials which influence indoor air environment and human health. Titanium dioxide ($TiO_2$) is photocatalyst extensively used in degradation of organic compound. To improve the photocatalytic activity in the visible light region, doping with non-metals element or loading noble metals on the surface of $TiO_2$ is generally proposed. In this study, N- doped $TiO_2$ having photocatalytic activity in visible light region was attached noble metal such as Pt, Ag, Pd, Au by coupling method. Catalytic activities of Noble metal coupled $N-TiO_2$ powders were evaluated by the improvement of their photocatalytic activities and the degradation of VOC gas. A UV-Vis spectrophotometer was used to measure the diffuse reflectance spectra of coupled $N-TiO_2$ sample. The photocatlytic activities of as prepared samples were characterized by the decoloration of aqueous MB solution under Xenon light source (UV and visible light). To measure of decomposition VOCs, ethylbenzene was selected for target VOC material and the concentration was monitored under UVLED irradiation in a closed chamber system. Adjusting the initial concentration of 10~12 ppm, to evaluate the removal characteristics by using the coupled $N-TiO_2$.