• Journal of the Korean Wood Science and Technology
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• 제24권4호
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• pp.47-55
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• 1996

UV transmission spectra of water-soluble acrylic resin films containing hydroxybenzophenolic, hydroxyphenylbenzotriazolic UV absorber and HALS(hindered amine light stabilizer) were investigated by exposure time(before exposure weathered for 160 and 320hours) in QUV Weather-Ometer. Also the YID(yellowness index difference), LID(lightness index difference) and CD(color difference) of dried water-soluble acrylic resin films and the coated woods of Larix leptolepis were analyzed by addition level of UV absorber(0, 1, 2 and 3%) and HALS(0, 0.5, 1 and 1.5%) and by exposure time in QUV Weather-Ometer. They showed no significant effects on UV transmission spectra of dried water-soluble acrylic resin films in the range of 300 to 400nm irrespective of exposure time. However, UV transmission decreased as increase of exposure time. UV transmission spectra were lower in dried water-soluble acrylic resin films containing hydroxybenzophenolic UV absorber and HALS than in these containing hydroxyphenylbenzotriazolic UV absorber and HALS in the range of 350 to 400nm. The least YID, LID and CD in the coated woods of Larix leptolepis appeared at the addition level of 3%, based on non-volatile content, in hydroxybenzophenolic and hydroxyphenylbenzotriazolic UV absorber, and of 1.5% in HALS to water-soluble acrylic resin.

• 한국전기전자재료학회논문지
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• 제26권4호
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• pp.315-320
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• 2013

The composites composed of conducting polymer (MEH-PPV), CdTe nanoparticles, and multiwalled carbon nanotubes (MWNTs) were spectroscopically and electrically characterized in their thin films. The composite films were prepared by spray coating. These composites were prepared from the mixture solution of MEH-PPV and CdTe-embedded MWNTs, in which CdTe nanoparticles were electrostatically bound to MWNTs. UV/vis and PL spectra were analyzed to investigate the optical absorbance and emission of the composite films. In addition, their structural, electrochemical, and electrical properties were studied by transmission electron microscopy, cyclic voltammetry, and I-V measurement.

• 한국광학회지
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• 제8권2호
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• pp.122-127
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• 1997

CdSe 양자 구슬 구조의 X선 회절 무늬를 조사하여 그 결정 구조가 육각 결정 구조임을 밝혔고, 선형 흡수 스펙트럼으로부터 양자 구속 효과에 의한 흡수 봉우리들이 나타남을 확인하였다. 에너지가 낮은 에너지 준위보다 높은 에너지 준위에 많은 전자-양공 짝을 만들었을 때, 낮은 에너지 준위에 대한 흡수 봉오리의 흡수 계수 변화가 작게 일어남을 관찰함으로써 띠내 전이의 선택률이 잘 지켜지고 있음을 확인하였다. 이로부터 실험에 사용된 CdSe 양자 구슬 구조가 크기 및 모양의 불규칙성으로 인한 불균일계라기 보다는 균일계로 기술되어짐을 밝혔다.

• 한국세라믹학회지
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• 제47권2호
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• pp.189-194
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• 2010

Compared with organic fluorophores, semiconductor quantum dots (QDs) have the better properties such as photostability, narrow emission spectra coupled to tunable photoluminescent emissions and exceptional resistance to both photo bleaching and chemical degradation. In this work, CdSe/ZnS QDs nanobeads were prepared by the incorporation of CdSe/ZnS QDs with mesoporous silica to use as the optical probe for detecting toxic and bio- materials with high sensitivity, CdSe/ZnS core/shell QDs were synthesized from the precursors such as CdO and zinc stearate with the lower toxicity than pyrotic precursors. The QD-nanobeads were characterized by transmission electron microscopy, FL microscopy, UV-Vis and PL spectroscopy, respectively.

• 약학회지
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• 제52권6호
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• pp.426-433
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• 2008

The interaction of cadmium (II) ion with protocatechuic acid ($H_3PA$) and ethylenediaminetetraacetic acid (EDTA) were investigated in aqueous solution at different pH. The protocatechuic acid and EDTA/cadmium stochiometries for cadmium (II) binding have been determined by UV-vis spectrophotometric method. The complexation of Cd (II) ion with protocatechuic acid was formed in solution. Among the two potential sites of chelation present in the protocatechuic acid structure, the carboxylic function presents higher complexation power toward Cd (II). 1 : 1 Cd (II)-complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH when interacted with protocatechuic acid in 0.2 M $NH_3$ - 0.2 M ${NH_4}Cl$ (pH 8.0) buffer. These results suggest that Cd $({H_2}PA)^+$ complex has the optimal condition of chelation in buffer solution at 64.22 ${\mu}M$ protocatechuic acid (A=1.01455).

• 반도체디스플레이기술학회지
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• 제10권1호
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• pp.95-99
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• 2011

$(1-x)BaTiO_3+(x)Cd_5(PO_4)_3Cl$ ceramics were prepared by the conventional ceramic technique, i.e., solid state reaction at high temperature. The concentration of $Cd_5(PO_4)_3C$ was varied from 0.01 to 0.15 mole fraction. In order to study the phase transitions of our ceramics, the Raman scattering spectra were measured as functions of concentration x and temperature. It was found that the soluble limit of $Cd_5(PO_4)_3Cl$ in $BaTiO_3$ was the x=0.05 composition and $BaTiO_3$ phase disappeared above x=0.10. A new phase identified as $Ba_4Ti_3P_2O_{15}$ was detected in all samples of our compositions. The Curie temperature shifts up to $130^{\circ}C$ as the concentration x increases from zero to 0.05 and shift down to $95^{\circ}C$ as further increases to 0.08. For the increase of the Curie temperature, it is suggested that it can result from the inhibition of displacement of $Ti^{4+}$ in the distorted octahedron due to well dispersed $Ba_4Ti_3P_2O_{15}$ and $Cd_5(PO_4)_3Cl$ phase.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.803-809
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• 2009

Notable blue shifts of the ν2 $C{\equiv}N$ stretching, $_{v4}$ C-C stretching and $_{v8}$ CCN deformation bands of $CD_3CN$ are observed upon solvation of $InCl_3$, resulting from the donor-acceptor interaction. The Raman spectrum in the $_{v2}$ region shows further details; at least two new bands emerge on the blue side of the $_{v2}$ band of free $CD_3CN$, whose relative intensities vary with concentration, suggesting that there exist at least two different cationic species in the solution. The strong hydrogen bonds formed between the methyl group and ${InCl_4}^-$ result in a large band appearing on the red side of the ν1 $CD_3$ symmetric stretching band. The solvation number of $InCl_3$, determined from the Raman intensities of the $C{\equiv}N$ stretching bands for free and coordinated $CD_3CN$, increases from $\sim$1.5 to $\sim$1.8 with decreasing concentration.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.411-414
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• 2013

In order to enhance the photovoltaic property of the CdS/CdSe co-sensitized quantum dot sensitized solar cells (QDSSCs), the surface of nanoporous $TiO_2$ photoanode was modified by ultrathin $Al_2O_3$ layer before the deposition of quantum dots (QDs). The $Al_2O_3$ layer, dip-coated by 0.10 M Al precursor solution, exhibited the optimized performance in blocking the back-reaction of the photo-injected electrons from $TiO_2$ conduction band (CB) to polysulfide electrolyte. Transient photocurrent spectra revealed that the electron lifetime (${\tau}_e$) increased significantly by introducing the ultrathin $Al_2O_3$ layer on $TiO_2$ surface, whereas the electron diffusion coefficient ($D_e$) was not varied. As a result, the $V_{oc}$ increased from 0.487 to 0.545 V, without appreciable change in short circuit current ($J_{sc}$), thus inducing the enhancement of photovoltaic conversion efficiency (${\eta}$) from 3.01% to 3.38%.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.965-970
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• 2012

Structure and optical properties of cadmium sulphide-zinc oxide composite nanorods have been evaluated by suitable characterization techniques. The X-ray diffraction spectrum contains a series of peaks corresponding to reflections from various sets of lattice planes of hexagonal ZnO as well as CdS. The above observation is supported by the Micro-Raman spectroscopy result. The optical reflectance spectra of CdS-ZnO is compared with that of ZnO where we observe an enhanced absorption and hence diminished reflection from CdS-ZnO compared to that from only ZnO. A very small intensity of the visible photoluminescence peak observed at 550 nm proves that the ZnO nanorods have very low concentrations of point defects such as oxygen vacancies and zinc interstitials. The photocurrent in the visible region has been significantly enhanced due to deposition of CdS on the surface of the ZnO nanorods. CdS acts as a visible sensitizer because of its lower band gap compared to ZnO.

• 대한화학회지
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• 제23권1호
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• pp.7-14
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• 1979

Poly(trans-5-methylproline) (PTMP)의 변광회전에 따른 CD, ORD 및 uv 스펙트럼의 변화를 관찰하였다. PTMP의 정방향 변광회전은 유기강산이나 trifluoroethanol (TFE) 속에서 일어나며 역방향 변광회전은 TFE용액을 과량의 지방족 알코올로서 회전시킬때 일어났다. 정방향과 역방향 변광회전시의 CD, ORD, 및 uv 스펙트럼의 변화는 polyproline 변광회전시의 변화와 평형하게 일어났다. PTMP의 정방향 변광회전시 ${\alpha}CH-$양성자의 화학적이동은 0.3 ppm downfield로 이동하였고 환원 점도는 0.15에서 0.26(dl/g)로 증가하였다 적당한 용매의 혼합물에서는 형태 I 과 II는 평형을 이루었다. 이러한 모든 용액성질의 변화는 polyproline의 변화와 유사하기 때문에 I, II의 두 형태는 polyproline 형태 I, II와 같을 것이며 형태 I은 모두 시스아미드 결합을 가진 helix이고, 형태 II는 모두 트란스 아미드 결합을 가진 helix일 것이다.