• 한국광학회:학술대회논문집
• /
• 한국광학회 2002년도 하계학술발표회
• /
• pp.98-99
• /
• 2002

대표적인 II-VI족 극성 반도체 결정인 ZnTe[001]와 ZnCdTe MQW에서 시료의 에너지 띠보다 낮은 에너지의 펨토초 티타늄 사파이어 레이저를 이용하여 결맞는 포논을 발생시키고 그 특성을 관찰하였다. 결맞는 포논의 신호는 그림1)과 같이 반사 및 투과형 전기 광학적 샘플링(Reflective/Transmissive Electro-Optic Sampling： REOS/TEOS)방법과 여기-탐사광 방법으로 시간 영역에서 측정하였다. (중략)

• Bulletin of the Korean Chemical Society
• /
• 제32권11호
• /
• pp.4021-4026
• /
• 2011

Functions of the luteinizing hormone releasing hormone (LHRH) and its induced release by divalent metal ions have received great attention because this neurotransmitter subsequently regulates the secretion of luteinizing hormone (LH). Metal-LHRH complexes were synthesized by addition of various Cu(II),Ni(II),Zn(II) ions into LHRH in order to understand how the induced release of LHRH is possible. The degree of complexation was monitored by $^1H$, $^{13}C$-NMR chemical shifts, and final products were identified by Mass spectrometry. Solutionstate structure determination of Zn(II)-LHRH out of metal-complexes was accomplished by using NMR and NMR-based distance geometry (DG). Interproton distance information from nuclear Overhauser effect spectroscopy was utilized for structure determination. Structure obtained in this study has a cyclic conformation exhibiting a specific ${\alpha}$-helical turn with residue numbers His[2]-Leu[7] out of 10 amino acids. Comparison of chemical shifts and EPR studies of Ni(II),Cu(II)-LHRH complexes exhibit that these metal complexes have 4-coordination geometry.

• 분석과학
• /
• 제11권2호
• /
• pp.145-149
• /
• 1998

Stability constants for the complexes of multidentate N,O-Schiff base ligands (bis-(salicylaldehyde)ethylendiamine(SED), bis-(salicylaldehyde)propylendiamine(SPD), bis-(salicylaldehyde)diethylenetriamine(SDT), bis-(salicylaldehyde)triethylenetetraamine(STT), and bis-(salicylaldehyde)tetraethylenepentaamine(STP) with Co(II) and Zn(II) were determined by a potentiometric method in a 70% dioxane-30% water mixture and ethanol, respectively. Stability constants for the complexes increased in the order of SPD

• 대한화학회지
• /
• 제57권3호
• /
• pp.341-351
• /
• 2013

Zn(II), Cd(II) and Hg(II) complexes with a general composition[$M(L)_2(X)_2$], where L=4-aminopyridine (4AP) and $X=NO_2{^-}$ were prepared under microwave irradiation. The metal complexes were characterized by elemental analyses, molar conductance, IR, Far-IR, electronic, NMR ($^1H$, $^{13}C$), XPS spectral and thermal studies. The spectroscopic studies reveal the composition, different modes of bonding, electronic transition, different chemical environment of C and H atoms and the electronic state of the metal atoms. On the basis of the characterization data, tetrahedral geometry is suggested for all the complexes. The free ligand (4-aminopyridine) and their metal complexes were screened against phytopathogenic fungi and bacteria in vitro and the activities were compared.

• 태양에너지
• /
• 제8권1호
• /
• pp.41-48
• /
• 1988

Heterojunction solar cells of $n-Cd_{1-x}Zn_xS/p-Si$ were fabricated by solution growth technique. The crystal structure, spectral response, surface morphology, and I-V characteristics of the $n-Cd_{1-x}Zn_xS/p-Si$ heterojunction solar cells were studied. The $Cd_{1-x}Zn_xS$ layer deposited on a silicon substrate (111) were found to be a cubic structure with the crystal orientation (111), (220) of the CdS and to be a hexagonal structure with crystal orientation (100) of the ZnS. The open-circuit voltage, short-circuit current, fill factor, and conversion efficiency of $n-Cd_{1-x}Zn_xS/p-Si$ heterojunction solar cell under $100mW/cm^2$ illumination were found to be 0.43V, 38mA. 0.76, and 12.4%, respectively.

• 대한금속재료학회지
• /
• 제50권7호
• /
• pp.531-538
• /
• 2012

In this study, we evaluated the fluidity of the Al-Zn based alloys which exhibit excellent mechanical properties. We conducted computer simulations of fluid flow using the results of DSC, DTA analysis and Java-based Materials Properties software (J. Mat. Pro). Such computer simulations were then compared with the results obtained from experimental observations. The computer simulation results and the experimental results were very similar in fluidity length. It was found that the fluidity length of Al-Zn alloys is improved by increasing the Zn content while decreasing the solidus temperature of an alloy. In addition, we elucidate the effect of Zn addition on variations in different mechanical properties and the microstructure characteristics of (Al-xZn3Cu0.4Si0.3Fe) x=20, 30, 40, and 45 wt% alloys fabricated by gravity casting.

• Bulletin of the Korean Chemical Society
• /
• 제24권8호
• /
• pp.1075-1080
• /
• 2003

We have investigated femtosecond coherent vibrational motions of Zn(II)-5,15-diphenylporphyrin in toluene using chirp-controlled ultrashort pulses. The oscillatory features superimposed on the temporal profiles of the pump-probe transient absorption signal are affected by the chirping and energy of excitation pulses. Using chirp- and excitation energy-controlled femtosecond pulses, we are able to obtain information on the structural changes between the electronic ground and excited states based on a comparative analysis of the Fouriertransformed frequency-domain spectra retrieved from the oscillatory components with the ground state resonance Raman spectra and normal mode calculations.

• Bulletin of the Korean Chemical Society
• /
• 제23권2호
• /
• pp.271-276
• /
• 2002

The energy relaxation dynamics of the lowest excited singlet and triplet states of the Zn(II)porphyrin monomer and its directly linked arrays were comparatively investigated with increasing the number of porphyrin moieties. While the fluorescence decay rates and quantum yields of the porphyrin arrays increased with the increase of porphyrin units, their triplet-triplet (T-T) absorption spectra and decay times remained almost the same. The difference in the trends of energy relaxation dynamics between the excited singlet and triplet states has been discussed in view of the electronic orbital configurations.

• KIEE International Transactions on Electrophysics and Applications
• /
• 제11C권3호
• /
• pp.58-62
• /
• 2001

Since Metallo-Porphyrin (MP) is very interesting compound due to its unique electronic and redox properties and it is also chemically and thermally stable, MP has been studied for potential memory and switching devices. In this study, thin films of 5,10,15,20-Tetrakis-Octadecyloxymethylphenyl-Porphyrin-Zn(II) were prepared by the Langmuir-Blodgett (LB) method and characterized by using UV/vis absorption spectroscopy and cyclic voltammetry. It was found that the proper transfer surface pressure for film deposition was 25 mN/m and the limiting area per molecule was 135 ${\AA}^2$/molecule. The current-voltage (I-V) characteristics of these films were investigated. Further details on the electrical properties of Porphyrin-Zn(II) derivative films will be discussed.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2007년도 춘계학술발표회 초록집
• /
• pp.49-50
• /
• 2007

MOCVD 법으로 사파이어 기판위에 ZnO 박막을 성장시켰으며, 이때 VI/II 족 유량비를 변화 시켜 나타나는 박막의 특성 변화에 대해 연구하였다. 유량비가 증가할수록 박막의 결정성과 광특성이 향상되는 것을 관찰할 수 있었다. 또한 유량비가 증가할수록 전기전도도와 캐리어 농도가 증가하는 것을 관찰할 수 있었다.