• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.82-85
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• 2004

Microinterface of W/Omicroemulsion prepared by phosphatidylcholine was used as reaction media of hydrolysis of phosphatidylcholine by phospholipaseA$_2$. Phosphatidylcholine was used as an amphiphile and was acted as a substrate. Organic phase of W/Omicroemulsion in this study was prepared by mixed organic solvents i.e. 2,2,4-trimethylpentane (isooctane) as a main solvent and 1-butanol as a co-solvent. The effect of added 1-butanol was remarkable not only on reaction beginning but also on high reaction rate. The hydrolysis reaction was dramatically initiated when 1-butanol was injected into the running isooctane/PC system. The enhancement by 1-butanol addition into single organic solvent was our original finding compare with previous conventional organic solvent. The reaction rate was elevated by the added amount of 1-butanol. The enhanced reaction rate was about 150-folds. This enhancement was speculated as 1-butanol adsorption on the microinterface. The adsorbed 1-butanol improved the properties of microinterface, especially its mobility was increased by difference of the chain length between phosphatidylcholine and 1-butanol. PhospholipaseA$_2$ molecules were located on the microinterface due to modified mobility of microinterface. Located phospholipaseA$_2$ on the microinterface reacted easily with phosphatidylcholine molecule. As a result high reaction rate was obtained. Microinterfacial properties were successfully improved by adsorbed 1-butanol molecule, and were favorable to appear higher reactivity of phospholipaseA$_2$.

• Mass Spectrometry Letters
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• 제12권4호
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• pp.192-199
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• 2021

Alpine glaciers harbor a large quantity of bio-labile dissolved organic matter (DOM), which plays a pivotal role in global carbon cycling as glacial-fed streams are headwaters of numerous large rivers. To understand the complexity, origin, and fate of DOM in glaciers and downstream-linked streams and lakes, we elucidated the molecular composition of DOM in two different Tibetan Plateau glaciers, eight glacial-fed streams and five lakes, using an ultrahigh-resolution 15 Tesla Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The compositional changes of the DOM samples revealed that glacier DOM mostly exhibited sulfur-containing organic compounds (CHOS species). We also found that aliphatic formulae contributed more than 50% of the total abundance of assigned molecules in glacier samples, and those compounds were significantly related to CHOS species. The CHO proportions of glacial-fed streams and lakes samples increased with increasing distance from glacial terminals. The relative contribution of terrestrial-derived organics (i.e., lignins and tannins) declined while microbial-originated organics (aliphatics) increased with increasing elevation. This suggested the gradual input of allochthonous materials from non-glacial environment and the degradation of microbe-derived compounds along lower elevations. Alpine glaciers are retreating as a result of climate change and they nourished numerous streams, rivers, and downstream-linked lakes. Therefore, the interpretations of the detailed molecular changes in glacier ice, glacial-fed streams, and alpine lakes on the Tibetan Plateau could provide broad insights for understanding the biogeochemical cycling of glacial DOM and assessing how the nature of DOM impacts fluvial ecosystems.

• 한국진공학회지
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• 제16권2호
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• pp.99-104
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• 2007

[ $Febry-P{\acute{e}}rot$ ] 프린지 패턴 (fringe pattern)과 광발광성 (photoluminescence, PL)의 광학적 성질을 동시에 가지고 있는 다공성 실리콘을 이용하여 가스센서를 개발하였다. 다공성 실리콘 샘플은 p-type 실리콘 웨이퍼 (boron-doped, <100> orientation, resistivity $1{\sim}10{\Omega}$)를 이용하여 전기화학적 식각을 통하여 만들어 졌다. 다공성 실리콘 샘플들은 열적 산화 방법과 hydrosilylation 방법을 통하여 그 표면이 수소로 종결된 다공성 실리콘 (Si-H)과 산화된 다공성 실리콘(Si-OH), 두 가지 각각 다른 표면 성질을 갖는 다공성 실리콘을 제작 하였다. 준비된 두 가지 다른 다공성 실리콘 칩들은 메탄올, 아세톤, 헥산, 그리고 톨루엔의 증기에 노출 시켰을 때 Febry-P rot 프린지 패턴의 변화나 PL의 변화를 관측하여 다공성 실리콘을 이용한 VOCs (volatile organic compounds) 센서로서의 응용에 대하여 연구하였다. $Febry-P{\acute{e}}rot$ 프린지 패턴은 유기 물질의 증기압이 클수록 단파장으로 이동하는 폭이 컸고, 광 발광성은 극성도가 큰 물질일수록 소강현상이 크게 일어나는 것을 알 수 있었다.

• Fibers and Polymers
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• 제2권3호
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• pp.135-140
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• 2001

Organic-inorganic hybrid composites consisting of poly(vinylidene fluoride) (PVDF) and SiO$_2$ were prepared through a sol-gel process and the crystallization behavior of PVDF in the presence of $SiO_2$ networks was investigated by spectroscopic, thermal and x-ray diffraction measurements. The hybrid composites obtained were relatively transparent, and brittleness increased with increasing content of tetraethoxysilane (TEOS). It was regarded from FT-lR and DSC thermal analyses that at least a certain interaction existed between PVDF molecules and the $SiO_2$ networks. X-ray diffraction measurements showed that all of the hybrid samples had a crystal structure of PVDF ${\gamma}$-phase. Fresh gel prepared from the sol-gel reaction showed a very weak x-ray diffraction peak near 2$\theta$=$21^{\circ}$ due to PVDF crystallization, and Intensity increased grade-ally with time after gelation. The crystallization behavior of PVDF was strongly affected by the amount of $SiO_2$ networks. That is, $SiO_2$ content directly influenced preference and disturbance fur crystallization. In polymer-rich hybrids, $SiO_2$ networks had a favorable effect on the extent of PVDF crystallization. In particular, the maximum portent crystallinity of PVDF occurred at the content of 3.7 wt% $SiO_2$ and was higher than that of pure PVDF. However. beyond about 10 wt% $SiO_2$, the crystallization of PVDF was strongly confined.

• 통합자연과학논문집
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• 제9권2호
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• pp.94-102
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• 2016

The crystal structure of the potential active 6-ethoxy-3-phenyl-5a,9a-dihydro-3H-chromen[4,3-c][1,2]oxazole-3a(4H)-carbonitrile ($C_{19}H_{15}N_2O_3$) has been determined from single crystal X-ray diffraction technique. The title compound crystallizes in the monoclinic space group C2/c with unit cell dimension a= 29.3026(9) ${\AA}$, b= 6.7695(2) ${\AA}$ and c= 19.7597(6) ${\AA}$ [${\alpha}= 90^{\circ}$, ${\beta}= 125.709(10)^{\circ}$ and ${\gamma}= 90^{\circ}$]. Single crystals suitable for X-ray diffraction were obtained by slow evaporation method, the isoxazole and six membered pyran rings adopts envelope conformation. The crystal packing of the molecules is stabilized by the weak $C-H{\ldots}N$ hydrogen bond interaction.

• 통합자연과학논문집
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• 제9권2호
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• pp.103-112
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• 2016

The crystal structure of the potential active Methyl 8-bromo-3-phenyl-5a,9a-dihydro-3H-chromen [4,3-c][1,2] isoxazole-3a(4H)-carboxylate ($C_{18}H_{15}BrNO_4$) has been determined from single crystal X-ray diffraction technique. The title compound crystallizes in the triclinic space group Pī with unit cell dimension a=8.3129 (3) ${\AA}$, b=9.5847 (4) ${\AA}$ and c=11.1463(4) ${\AA}$ [${\alpha}=98.457(3)^{\circ}$, ${\beta}=102.806(2)^{\circ}$ and ${\gamma}=105.033(5)^{\circ}$]. Single crystals suitable for X-ray diffraction were obtained by slow evaporation method, the isoxazole and six membered pyran rings adopts envelope conformation. In the crystal, molecules are linked via pairs of inter molecular $C-H{\ldots}O$ hydrogen bonds to form dimmers.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.420-425
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• 2012

The new organic semiconductors which are composed of divinylbenzene core unit and alkoxynaphthalene on both sides, 1,4-bis-2-(6-octyloxy)naphthalen-2-ylvinylbenzene (BONVB), 1,4-bis-2-(6-decyloxy)naphthalen-2-ylvinylbenzene (BDNVB) and 1,4-bis-2-(6-dodecyloxy)naphthalen-2-ylvinylbenzene (BDDNVB) were synthesized by Wittig reaction. The structures of obtained BONVB, BDNVB and BDDNVB were confirmed by FT-IR and mass spectroscopy. UV-absorption of thin film showed H-aggregates and J-aggregates due to closely packed structure between adjacent molecules. The characterization of vacuum-evaporated films by Xray diffraction (XRD) and atomic force microscopy (AFM) showed that the chain length of alkoxy group affects the crystallinity and morphology. BONVB with octyloxy group showed the mobility of $0.011cm^2/V{\cdot}s$, on/off ratio of $1.31{\times}10^5$, and a subthreshold slope of 0.93 V.

• 분석과학
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• 제30권3호
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• pp.138-145
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• 2017

Microwave-assisted organic synthesis has gained a remarkable interest over the past years because of its advantages - (i) rapid energy transfer and superheating, (ii) higher yield and rapid reaction, (iii) cleaner reactions. Ionic liquids are well known for their unique properties such as negligible vapor pressure and high thermal stability. With these properties, ionic liquids have gained increasing attention as green, multi-use reaction media. Recently, ionic liquids have been applied as reaction media for biocatalysis. Lipase-catalyzed reactions in ionic liquids provide high activity and yield compared to conventional organic solvents or solvent free system. Since polar molecules are generally good absorbent to microwave radiation, ionic liquids were investigated as reaction media to improve activity and productivity. In this study, therefore, the effect of microwave irradiation in ionic liquids was investigated on lipase catalyzed reactions such as benzyl acetate synthesis and caffeic acid phenethyl ester synthesis. Comparing to conventional heating, microwave heating showed almost the same final conversion but increased initial reaction rate (3.03 mM/min) compared to 2.11 mM/min in conventional heating at $50^{\circ}C$.

• 통합자연과학논문집
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• 제8권1호
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• pp.19-29
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• 2015

In view of the growing medicinal importance of chromene and its derivatives, the single crystal X-ray diffraction study was carried out for the potential active 4,6-dimethyl-9-phenyl-8,12-dioxa-4,6-diazatetracyclo [8.8.0.02,7.013,18]octadeca-2(7),13,15,17-tetraene-3,5,11-trione-2-ethoxyphenyl (2E)-but-2-enoate ($C_{18}H_{20}N_2O_5$). In the title compound are two molecules exist in the asymmetric unit. It crystallizes in the monoclinic space group $P2_1/c$ with unit cell dimension a=14.608(3) ${\AA}$, b=12.845(3) and c= 17.781(4) [alpha & gamma=$90^{\circ}$ beta=$91.233(5)^{\circ}$]. Both pyran and pyran ring of the chromene moiety adopts sofa conformation in the molecule A & B. The crystal structure is stabilized by intramolecular C-H...O hydrogen bond interaction.

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1150-1154
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• 2003

The reactions of [Ni(L)(H₂O)₂]Cl₂ (L = 2,5,9,12-tetramethyl-1,4,8,11-tetraazacyclotetradecane) with terephtalate (tp) and 2,5-pyridinedicarboxylate (pdc) generate one-dimensional nickel(II) complexes, [Ni(L)(H₂O)₂](tp) · ₄H₂O (1) and [Ni(L)(H₂O)₂](pdc)·₄H₂O (2). The structures have been characterized by X-ray crystallography, magnetic susceptibility and spectroscopy. The crystal structures of 1 and 2 show a distorted octahedral coordination geometry around the Ni(II) ion, with secondary amines of the macrocycle and two water molecules at the trans position. Complexes 1 and 2 display the one-dimensional hydrogen-bonded infinite chains. The magnetic behavior of all compounds exhibits weak interchain antiferromagnetic interactions with J values of -1.09(3) for 1 and -1.14(2) cm-1 for 2.