• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3553-3560
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• 2010

A new hydrazone derivative compound has been synthesized and characterized by IR, $^1H$-NMR, $^{13}C$-NMR and UV-vis. spectroscopy techniques, elemental analysis and single-crystal X-ray diffraction (XRD). The new compound crystallizes in monoclinic space group C2/c. In addition to the crystal structure from X-ray experiment, the molecular geometry, vibrational frequencies and frontier molecular orbitals analysis of the title compound in the ground state have been calculated by using the HF/6-31G(d, p), B3LYP/6-311G(d, p) and B3LYP/6-31G(d, p) methods. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the observed experimental bands. To determine conformational flexibility, molecular energy profile of (1) was obtained by semi-empirical (AM1) calculation with respect to a selected degree of torsional freedom, which was varied from $-180^{\circ}$ to $+180^{\circ}$ in steps of $10^{\circ}$. Molecular electrostatic potential of the compound was also performed by the theoretical method.

• Macromolecular Research
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• 제9권2호
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• pp.116-121
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• 2001

A series of poly(1,4-phenylenevinylene-alt-3-alkyl-2,5-thienylenevinylene)s (alkyl = hexyl [PPV-alt-6-TV] and octyl (PPV-alt-8-TV] group) have been synthesized by the Heck coupling reaction. These polymers were characterized using $^1$H-NMR, FT-IR spectroscopy, and thermogravimetric analysis (TCA). They are solvent processible and have obviously copolymeric structure. The photophysical properties of the polymers were investigated using UV-visible and steady-state photoluminescence(PL) spectroscopy. We studied the change of light-emitting properties by incorporating the thiophene group into the PPV polymer backbone using alternating copolymer system. The properties of two synthesized polymers are very similar, but they exhibited apparent changes of light-emitting properties compared with other PPV backbone based polymers. The broad absorption bands from 350 to 570 nm are due to $\pi$-$\pi$* transitions of the polyconjugated systems. The absorption maxima of the two polymers were found at about 452 and 448 nm for PPV-alt-6-TV and PPV-alt-8-TV, respectively. The copolymers showed broad PL spectra between 550 and 700 nm without vibronic bands and PL emission maxima of PPV-alt-6-TV and PPV-alt-8-TV are about 620 and 605 nm, respectively. The copolymers exhibited the red emission (PPValt-6-TV), but more red shifted emissions are needed to obtain real red color.

• 암석학회지
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• 제10권3호
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• pp.233-245
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• 2001

NMR분광법은 현재 화학에서 빼 놓을 수 없는 아주 중요한 연구방법의 하나지만 또한 지질학의 연구에 있어서도 초전도 자석의 발달과 함께 그 중요성이 부각되고 있다. 지질학에 있어서 NMR의 연구 대상 원소로는 광물의 주 구성 성분이며 여러 가지 구조적 정보를 갖고 있는 $^{29}Si$, $^{27}Al$ 등이 유용하게 사용되며 이들은 각각 다른 여러 정보들을 제공한다. 이 밖에도 $^{23}Na$와 같은 알칼리금속과 더불어 다양한 핵종들이 지질학에서 NMR로 연구되고 있다. NMR을 이용하여 다양한 방면의 연구들이 가능한데 NMR은 XRD, TEM보다도 더욱 작은 미시적인 (분자적 관점에서의) 구조 연구에 사용될 수 있다. 이러한 연구를 통해 Al, Si 질서-무질서, 산소원자와의 배위수, 인근의 다른 양이온의 분포 등을 포함한 구조적 정보를 알 수 있다. 또한 NMR의 또 다른 장점은 정적인 미시 구조뿐만 아니라 분자들의 움직임(dynamics)에 대한 정보도 알 수 있다는 것이다. 이러한 동적인 정보는 기존의 어느 방법으로도 알기 어려웠던 부분이고 NMR을 통하여 분자들의 상호 교환 속도와 활성화 에너지 등에 대한 폭 넓은 이해가 가능할 수 있다. 이 밖에 NMR을 이용하여 비정질 물질에 대한 구조와 더불어 지표면에서 산출되는 유기물에 대한 성분 및 구조도 아주 중요하게 연구될 수 있는 분야이다.

• 한국진공학회지
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• 제7권4호
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• pp.361-367
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• 1998

유기 박막 트렌지스터의 활성층으로 사용하기 위하여 공액성 소중합체인 $\alpha$ -sexithiophene($\alpha$-6T)이라는 시료를 가지고 유기 분자선 증착법(OMBD)을 이용하여 박막 을 제작하였으며 $\alpha$-6T박막의 성막 조건에 따른 박막의 분자 배향, 결정구조 그리고 표면 특성을 알아보기 위해 angle-resolved UV/visible absorption spectroscopy, X-ray diffractometry(XRD) 그리고 atomic force microscopy(AFM)를 이용하였으며 그 분석 결과 성막 조건에 관계없이 모두 monoclinic한 결정구조를 갖으나, 초고진공, 낮은 성막 속도, 기 판의 온도가 높은 조건일 경우 $\alpha$-6T 분자들이 기판에 수직적으로 배열한다는 것을 확일할 수 있었다.

• Elastomers and Composites
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• 제48권1호
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• pp.2-9
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• 2013

rac-$Et(Ind)_2ZrCl_2$ 메탈로센 촉매와 메틸알루미늄옥산 공촉매를 이용하여 polyethylene, poly(ethylene-co-1-decene), poly(ethylene-co-p-methylstyrene) 및 poly(ethylene-ter-1-decene-ter-p-methystyrene)를 합성하였다. $^{13}C$ NMR과 $^1H$ NMR 및 FT-IR을 이용하여 삼원공중합체의 특성을 분석하였다. 삼원공중합의 최적조건을 확립하기 위해 동일한 중합조건을 유지한 채 촉매량, 공촉매/촉매 몰비, 중합 시간 및 중합 온도를 변경하여 실험하였다. 촉매량이 증가할수록 삼원공중합체의 촉매활성도 및 중량평균분자량은 증가하였으나, 중합시간이 30분을 초과하자 촉매활성도는 감소하였다. 공촉매/촉매 몰비를 증가시킨 결과 중량평균분자량은 감소하였고, 촉매활성도는 어느 정도 증가하였다. 촉매활성도는 중합온도가 증가함에 따라 상승하였으나 중량평균 분자량은 감소하였다.

• Journal of Electrochemical Science and Technology
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• 제13권2호
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• pp.237-253
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• 2022

The methyl 2-(1,3-dithietan -2- ylidene)-3-oxobutanoate (MDYO) and 2-(1,3-dithietan-2-ylidene) cyclohexane -1,3-dione (DYCD) were synthesized and tested at various concentrations as corrosion inhibitors for 316L stainless steel in 1 M HCl using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface analysis techniques (SEM / EDX and Raman spectroscopy) and Functional Density Theory (DFT) was also used to calculate quantum parameters. The obtained results indicated that the inhibition efficiency of MDYO and DYCD increases with their concentration, and the highest value of corrosion inhibition efficiency was determined in the range of concentrations investigated (0.01 × 10^-3 - 10^-3 M). Polarization curves (Tafel extrapolation) showed that both compounds act as mixed-type inhibitors in 1M HCl solutions. Electrochemical impedance spectra (Nyquist plots) are characterized by a capacitive loop observed at high frequencies, and another small inductive loop near low frequencies. The thermodynamic data of adsorption of the two compounds on the stainless steel surface and the activation energies were determined and then discussed. Analysis of experimental results shows that MDYO and DYCD inhibitors adsorb to the metal surface according to the Langmuir model and the mechanism of adsorption of both inhibitors involves physisorption. SEM-EDX results confirm the existence of an inhibitor protective film on the stainless steel surface. The results derived from theoretical calculations supported the experimental observation.

• 한국식품영양과학회지
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• 제43권10호
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• pp.1535-1542
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• 2014

어류 부산물인 명태 껍질에서 콜라겐을 추출하기 위하여 0.1 N NaOH로 알칼리 처리 후 pepsin으로 효소 처리하였고 저분자화를 위해 neutrase를 이용하여 분자량별로 콜라겐을 제조하였다. 콜라겐은 1 kDa 이하, 1~3 kDa, 3~10 kDa 및 10 kDa 이상으로 분자량별로 분리하여 이화학적 특성 및 생리활성을 조사하였다. 분자량에 따른 콜라겐 함량은 1 kDa 이하에서 36.43%로 가장 높았으며 유리 아미노산 조성은 1 kDa 이하, 1~3 kDa, 3~10 kDa 및 10 kDa 이상에서 각각 1,603.69, 1,000.55, 475.04, 415.73 mg/100 g으로 분자량이 작을수록 유리 아미노산의 함량이 높게 나타났다. 콜라겐의 분자구조를 Fourier transform infrared spectroscopy로 측정한 결과 분자량에 따른 콜라겐 모두 amide A, amide I, amide II, amide III의 범위에 wavenumber 속에 포함되었으며 콜라겐 표준품과 유사한 peak band 값을 나타내어 화학구조가 동일함을 알 수 있었다. 전자공여능과 superoxide dismutase 유사 활성은 1 kDa 이하에서 각각 29.51%, 38.45%로 가장 높았으며 분자량이 커질수록 그 값은 감소하였다. 멜라닌 합성에 미치는 영향을 확인하기 위해 ${\alpha}$-MSH를 첨가한 tyrosinase 활성 측정은 1 kDa 이하에서 농도 유의적으로 tyrosinase 활성을 저해시키는 것을 확인할 수 있었으며, 광노화에 의한 피부 주름 개선 효과는 HS68 cell을 이용하여 MMP-1 저해 활성을 측정하였고 그 결과 10 kDa 이상에서는 MMP-1 저해 활성이 나타나지 않았으나 3 kDa 이하에서는 MMP-1 저해 활성이 나타나 세포 보호 효과가 있음을 확인하였다. 콜라겐의 분자량은 항산화 활성 및 생리활성과 유의적인 상관관계를 나타내어 저분자 콜라겐은 기능성 식품 및 화장품 소재로서 활용 가능할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권11호
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• pp.1575-1589
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• 2017

Objective: This study was conducted to determine molecular structures related to carbohydrates and lipid in alfalfa hay cut at early bud, late bud and early flower and in the afternoon and next morning using Fourier transform infrared spectroscopy (FT/IR) and to determine their relationship with alfalfa hay nutrient profile and availability in ruminants. Methods: Chemical composition analysis, carbohydrate fractionation, in situ ruminal degradability, and DVE/OEB model were used to measure nutrient profile and availability of alfalfa hay. Univariate analysis, hierarchical cluster analysis (CLA) and principal components analysis (PCA) were conducted to identify FT/IR spectra differences. Results: The FT/IR non-structural carbohydrate (NSCHO) to total carbohydrates and NSCHO to structural carbohydrate ratios decreased (p<0.05), while lignin to NSCHO and lipid CH3 symmetric to CH2 symmetric ratios increased with advancing maturity (p<0.05). The FT/IR spectra related to structural carbohydrates, lignin and lipids were distinguished for alfalfa hay at three maturities by PCA and CLA, while FT/IR molecular structures related to carbohydrates and lipids were similar between alfalfa hay cut in the morning and afternoon when analyzed by PCA and CLA analysis. Positive correlations were found for FT/IR NSCHO to total carbohydrate and NSCHO to structural carbohydrate ratios with non-fiber carbohydrate (by wet chemistry), ruminal fast and intermediately degradable carbohydrate fractions and total ruminal degradability of carbohydrates and predicted intestinal nutrient availability in dairy cows ($r{\geq}0.60$; p<0.05) whereas FT/IR lignin to NSCHO and CH3 to CH2 symmetric stretching ratio had negative correlation with predicted ruminal and intestinal nutrient availability of alfalfa hay in dairy cows ($r{\geq}-0.60$; p<0.05). Conclusion: FT/IR carbohydrate and lipid molecular structures in alfalfa hay changed with advancing maturity from early bud to early flower, but not during the day, and these molecular structures correlated with predicted nutrient supply of alfalfa hay in ruminants.

• Advances in environmental research
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• 제9권3호
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• pp.215-232
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• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1115-1120
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• 2008

The adsorption of CO on W(110) surfaces was studied using thermal desorption spectroscopy (TDS), and core and valence level spectroscopy. At 120 K, CO forms a tilted structure at lower coverages ($\alpha$ 1), whereas it adsorbs normal to the surface at higher coverages ($\alpha$ 2). Tilted structures have been suggested to be precursors of dissociative chemisorption; however, experimental evidence is provided for the non-dissociative chemisorption of CO at temperatures above 900 K (which is referred to as the $\beta$ -state): TDS shows first order desorption kinetics. The core and valence level spectra of O/W(110) and those of $\beta$ -CO/W(110) are different. Most importantly, the 4$\sigma$ molecular orbital of CO can be identified in the valence level spectra of the $\beta$ -CO.