• 전기학회논문지
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• 제61권4호
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• pp.595-600
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• 2012

In this paper, it is investigated the characteristics of DSSC(Dye Sensitized Solar Cell) with cell area(0.25, 1, 2.25 $cm^2$) and dye absorption time(12, 24, 36 h). Thus, we obtain the following results by using the EIS, UV-VIS, I-V measurement. When the cell area increases, the efficiency decreases to 21~32 percent because of the increase about 40~$60{\Omega}$ of internal impedance regardless of dye absorption time. When the absorption time increases up to 24 hours, the efficiency increases to over 40 percent cause of the reduction of internal impedance regardless of cell area. When the dye absorption time becomes 36 hours, the internal impedance increases and at the same time, in the range of 600~700 nm, as the optical absorption reduces. Therefore, the efficiency decreases to 19~31 percent. When it is absorbed the dye for 24 hours in the smallest cell area which is 0.25 $cm^2$, the DSSC has the best efficiency (7.11 %).

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1776-1782
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• 2005

ZnSe/ZnS, UV-blue luminescent core shell quantum dots, were synthesized via a thermal decomposition reaction of organometallic zinc and solvent coordinated Selenium (TOPSe) in a hot solvent mixture. The synthetic conditions of the core (ZnSe) and the shell (ZnS) were independently studied at various reaction temperature conditions. The obtained colloidal nanocrystals at corresponding temperatures were characterized for their optical properties by UV-vis, room temperature solution photoluminescence (PL) spectroscopy, and further obtained powders were characterized by XRD, TEM, and EDXS analyses. The synthetic temperature condition to obtain the best PL emission intensity for the ZnSe core was 300 ${^{\circ}C}$, and for the optimum shell capping, the temperature was 135 ${^{\circ}C}$. At this temperature, solution PL spectrum showed a narrow emission peak at 427 nm with a PL efficiency of 15%. In addition, the measured particle sizes for the ZnSe/ZnS nanocomposite via TEM were in the range of 5 to 12 nm. Furthermore, we have synthesized water-soluble ZnSe/ZnS nanoparticles by capping the ZnSe/ZnS hydrophobic surface with mercaptoacetate (MAA) molecules. For the obtained aqueous colloidal solution, the UV-vis spectrum showed an absorption peak at 250 nm, and the solution PL emission spectrum showed a peak at 425 nm, which is similar to that for hydrophobic quantum dot ZnSe/ZnS. However, the calculated PL efficiency was relatively low (0.1%) due to the luminescence quenching by water and MAA molecules. The capping ligand was also characterized by FT-IR spectroscopy, with the carbonyl stretching peak in the mercaptoacetate molecule appearing at 1575 $cm ^{-1}$. Finally, the particle sizes of the MAA capped ZnSe/ZnS were measured by TEM, showing a range of 12 to 17 nm.

• 폴리머
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• 제29권3호
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• pp.308-313
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• 2005

광감응성 azobenzene 그룹이 분자의 주위 환경에 따라 광이성화 반응이 변화하는 것을 in-situ UV/Vis 분광 실험법과 광학 이방성 측정법을 이용하여 조사하였다. 4-Hyhoxyazobenzene을 포함하는 필름에 광조사함과 동시에 trans-isomer와 cis-isomer 특성 피크의 세기 변화를 측정하여 azobenzene 그룹의 가역적이며 반복적인 광이성화 반응을 알수 있었다. Azobenzene 자기조립체 박막이 입혀진 기판을 액정 셀의 배향막으로 사용하여 액정의 배향을 유도하였을 때, trans-azobenzene 그룹들이 조밀한 packing을 하며 기판에 수직으로 배열한 자기조립체 구조 때문에 액정 분자들도 수직 homeotropic 배향을 하였다. 이와 같은 자기조립체 박막의 액정 셀에 UV 빛을 노광하면 azobenzene그룹이 광이 성화 반응을 일으켜 cis-isomer로 변하게 되며, 이로 인해 액정의 배향이 수직에서 수평 planar 배향으로 변함을 알 수있었다.

• 한국산학기술학회논문지
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• 제15권1호
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• pp.39-46
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• 2014

미얀마 Kayah산 녹색 투어말린의 특성을 X-선 형광분석, 자외선-가시광선 그리고 중적외선 분광분석을 통하여 타산지의 녹색 투어말린과 비교하였다. 화학성분 분류에 의해 미얀마 투어말린이 속한 그룹을 조사 하였다. 미얀마 투어말린은 V 원소를 많이 함유하고 있었고 X 사이트에 Ca 원소를 반 이상 함유한 Calcic 그룹에 속했고 우바이트 (Uvite)로 명명되었다. 자외선-가시광선 분석결과 $V^{3+}$ 이온에 의한 415와 611 nm에 강한 흡수밴드가 나타나 녹색 투어말린의 원인이 되었다. $Fe^{2+}$ 이나 $Cu^{2+}$ 이온에 의해 녹색이 나타나는 타산지의 녹색 투어말린과 차이가 있었다. 중적외선 분석에서는 수산기와 금속들 간의 진동에 의한 흡수가 일어났는데 1100 $cm^{-1}$ 근처에서 스트레칭 모드, 3500 $cm^{-1}$ 주변에서 벤딩 모드 그리고 4600과 4200 $cm^{-1}$ 사이에서 스트레칭과 벤딩 모드의 혼합 밴드가 나타났다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7143-7147
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• 2015

Gold nanoparticles (GNPs) were conjugated with gallic acid (GA) at various concentrations between 30 and $150{\mu}M$ and characterized using transmission electron microscopy (TEM) and UV-Vis spectroscopy (UV-VIS). The anticancer activities of the gallic acid-stabilized gold nanoparticles against well-differentiated (M213) and moderately differentiated (M214) adenocarcinomas were then determined using a neutral red assay. The GA mechanism of action was evaluated using Fourier transform infrared (FTIR) microspectroscopy. Distinctive features of the FTIR spectra between the control and GA-treated cells were confirmed by principal component analysis (PCA). The surface plasmon resonance spectra of the GNPs had a maximum absorption at 520 nm, whereas GNPs-GA shifted the maximum absorption values. In an in vitro study, the complexed GNPs-GA had an increased ability to inhibit the proliferation of cancer cells that was statistically significant (P<0.0001) in both M213 and M214 cells compared to GA alone, indicating that the anticancer activity of GA can be improved by conjugation with GNPs. Moreover, PCA revealed that exposure of the tested cells to GA resulted in significant changes in their cell membrane lipids and fatty acids, which may enhance the efficacy of this anticancer activity regarding apoptosis pathways.

• 폴리머
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• 제25권5호
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• pp.671-678
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• 2001

Sodium 또는 zinc로 중화된 poly(ethylene-co-methacrylic acid)의 아이오노머는 ethylene 사슬 부분들로만 이루어진 결정상, acid 그룹이 존재하는 amorphous 영역, 그리고 ionic aggregate의 세 가지 상으로 나누어진다. Soaking에 의하여 흡수된 nonionic dye 분자들은 결정상을 제외한 amorphous 부분이나 ionic aggregate 분근에 존재하는데, 주위 사슬의 극성에 따라 dispersion force (ethylene 사슬 부분), polar force (acid 부분), ionic dipole (ionic aggregate 부분)의 세 가지 다른 힘의 영향 아래 놓이게 된다. 극성이 적은 ethylene 사슬부분의 dispersion force 영향 아래에 존재하는 Nile Red의 UV/Vis 흡수피크는 500nm 부근에서, polar한 acid 그룹의 영향을 받는 dye 피크는 525 nm, 그리고 ionic aggregate의 영향에 의한 dye는 Na+-아이오노머의 경우 550 nm, divalent이어서 더 큰 ionic dipole을 가지는 $Zn^{2+}$-아이오노머의 경우 610nm에서 각각 피크가 나타났다.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2170-2174
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• 2010

The surfaces of $TiO_2$ and ZnO nanoparticles have been modified by gold (Au) nanoparticles by a reduction method in solution. Their interfacial electronic structures and optical absorptions have been studied by depth-profiling X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectroscopy, respectively. Upon Au-modification, UV-vis absorption spectra reveal a broad surface plasmon peak at around 500 nm. For the as-prepared Au-modified $TiO_2$ and ZnO, the Au $4f_{7/2}$ XPS peaks exhibit at 83.7 and 83.9 eV, respectively. These are due to a charge transfer effect from the metal oxide support to the Au. For $TiO_2$, the larger binding energy shift from that (84.0 eV) of bulk Au could indicate that Au-modification site of $TiO_2$ is different from that of ZnO. On the basis of the XPS data with sputtering depth, we conclude that cationic (1+ and 3+) Au species, plausibly $Au(OH)_x$ (x = 1-3), commonly form mainly at the Au-$TiO_2$ and Au-ZnO interfaces. With $Ar^+$ ion sputtering, the oxidation state of Ti dramatically changes from 4+ to 3+ and 2+ while that (2+) of Zn shows no discernible change based on the binding energy position and the full-width at half maximum (FWHM).

• 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.

• 한국응용과학기술학회지
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• 제32권1호
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• pp.16-22
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• 2015

빈카마이너 L.의 알칼로이드는 HPLC의 PDA 검출기를 이용하여 측정하고 이를 표준시료인 빈카민의 자외선/가시광선 흡수 스펙트럼과 비교하여 분석하였다. 플라보노이드류를 포함하여 추출물에서 9개 이상의 화합물에 대한 자외선/가시광선 흡수 스펙트럼을 얻었다. 추출방법에 따라 에탄올 추출물과 열수 추출물을 얻고 이를 DPPH 라디칼 소거법에 의해 항산화 효과를 조사하였다. 그 결과 에탄올 추출물과 열수 추출물 모두 비교군인 케르세틴과 비타민 C 대비 약 14~15%의 항산화 효과를 보여 추출법에 상관없이 유사한 결과를 보였다.

• 분석과학
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• 제8권3호
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• pp.305-311
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• 1995

Salicylic acid($C_6H_4(OH)COOH=H_2A$)와 전이금속인 Fe(III) 사이에 형성되는 착물의 안정도상수를 $20^{\circ}C$, 0.1M $KNO_3$ 수용액 중에서 자외-가시선 흡수광도법 및 pH 전위차적정법으로 측정하여 문헌값($logK_f=16.48$)과 비교하였다. $H_2A$의 $pK_{a1}$과 $pK_{a2}$는 $2.92{\pm}0.08$ 및 $12.90{\pm}0.13$이며, Fe(III)-$H_2A$의 1:1 착물의 $logK_f$는 $20^{\circ}C$에서 $11.88{\pm}0.12$였다.