• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.4005-4010
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• 2011

We investigated thermal behavior of spin-coated films of P(HB-co-HHx)/PEG blends by using infraredreflection absorption (IRRAS) spectroscopy and 2D correlation spectroscopy. Based on 2D IRRAS correlation spectra, we could determine the sequence of spectral intensity changes with increasing temperature that PEG band changes first and then a band for crystalline component of P(HB-co-HHx) changes before a band for amorphous component. The intensities of bands for PEG and amorphous P(HB-co-HHx) were changed greatly as PEG weigh % of P(HB-co-HHx)/PEG blends increased. Transition temperatures of P(HB-co-HHx)/PEG blends were successfully determined by 2D gradient mapping method. The transition temperature of spincoated films of 98/2 and 90/10 P(HB-co-HHx)/PEG blends and 80/20 P(HB-co-HHx)/PEG blend determined by 2D gradient map are, respectively, about 137.5 and $132.5^{\circ}C$. Furthermore, P(HB-co-HHx)/PEG blends show an additional transition temperature that have been interpreted in terms of different lamellar thicknesses in spin coated films.

• 대한화학회지
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• 제48권3호
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• pp.261-265
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• 2004

12-4라는 액정올리고머가 액정이 되는 과정에서 일어나는 동력학을 2차원 라만상관분광법을 이용하여 연구하였다. 분광법의 결과로부터 에틸그룹 옆에 붙어있는 자유 카보닐 그룹이 먼저 움직이고, 수소결합을 이룬 카보닐 그룹이 나중에 움직인다는 것을 알아내었다. 반면에 바이페닐그룹사이에 존재하는 자유 카보닐 그룹은 좀처럼 움직이지 않는 것으로 나타났다. 샘플-샘플상관분광법의 결과로부터는 액정이 되는 온도 135$^{\circ}C$보다 훨씬 낮은 온도인 50$^{\circ}C$에서 이미 카보닐 그룹의 움직임이 있음을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.849-852
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• 2009

The work describes EPR and 17O NMR measurements followed by theoretical calculation of the rotational correlation time $({\tau}_R)$, the water residence time $({\tau}_m)$, and the longitudinal electronic spin relaxation time $(T_{le})$(T_1e) for two new gadolinium complexes 1 and 2 of the type [$Gd(L)(H_2O)$] (L = tranexamic esters) in order to investigate their efficiency as a paramagnetic contrast agent (PCA). Of three correlation times, τR plays a major and predominant role to the unusually high relaxivity of 1 and 2 as compared with that of clinically approved MR CAs such as [$Gd(DTPA)(H_2O)]2‐ (Magnevist${\circledR}$), [Gd(DTPA-BMA)(H2O)] (Omniscan${\circledR}$), and $[Gd(DOTA)(H_2O)]^-$ (Dotarem${\circledR}$). The presence of bulky tranexamic ester in the ligand seems to be responsible for the conformational rigidity, which in turn causes such great an increase in ${\tau}_R$.

• Bulletin of the Korean Chemical Society
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• 제15권7호
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• pp.553-559
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• 1994

Dynamics of $CH_2CI$ group in ${\alpha},2,6$-trichlorotoluene dissolved in $CDCl_3$ was studied by observing various relaxation modes for $^{13}C$ under proton undecoupled condition. Partially relaxed $^{13}C$ spectra were obtained at $34^{\circ}C$ as a function of evolution time after applying various designed pulse sequences to this $AX_2$ spin system. It was found that nonlinear regression analysis of the relaxation data for these magnetization modes could provide the information about dipolar and spin-rotational auto-correlation and cross-correlation spectral densities for fluctuation of the $^{13}C-^1H$ internuclear vector in $CH_2Cl$ group. The results show that the effect of cross-correlation is comparable in magnitude to that of auto-correlation and the relaxation in this spin system is dominated by dipolar mechanism rather than spin-rotational one. From the resulting spectral density data we could calculate the bond angle ${\angle}HCH\;(105.1$^{\circ}$) and elements of the rotational diffusion tensor for $CH_2Cl$ group.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1375-1378
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• 2011

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.661-664
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• 2005

• 대한화학회지
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• 제52권4호
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• pp.369-379
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• 2008

• 대한화학회지
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• 제49권6호
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• pp.554-559
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• 2005

• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.143-146
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• 2006

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.255-258
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• 2000

The new approach for synthesis of novel condensation monomers and polyimides on the basis of them was developed. The correlation between synthesis regularities, structure and properties of monomers and polyimides was studied. The areas of industrial application of synthesized polymer were determined.