• 한국재료학회지
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• 제28권11호
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• pp.627-632
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• 2018

Two dimensional(2D) crystals, composed of a single layer or a few atomic layers extracted from layered materials are attracting researchers' interest due to promising applications in the nanoelectromechanical systems. Worldwide researchers are preparing devices with suspended 2D materials to study their physical and electrical properties. However, during the fabrication process of 2D flakes on a target substrate, contamination occurs, which makes the measurement data less reliable. We propose a dry transfer method using poly-methyl methacrylate(PMMA) for the 2D flakes to transfer onto the targeted substrate. The PMMA is then removed from the device by an N-Methyl-2-pyrrolidone solution and a critical point dryer, which makes the suspended 2D flakes residue free. Our method provides a clean, reliable and controllable way of fabricating micrometer-sized suspended 2D nanosheets.

• Archives of Pharmacal Research
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• 제11권3호
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• pp.244-246
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• 1988

Sulphamerazine-$N^1$-(methyl 2,3,4-tri-O-acetyl-${\beta}$-D-glucuronide) was successfully synthesized and characterized by proton NMR and mass spectrometry for the metabolic study of sulphamerazine.

• Archives of Pharmacal Research
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• 제21권6호
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• pp.723-728
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• 1998

The chemical behaviours of 4-methyl-2-oxo-2H-benzopyran-7-yl oxoacetyl hydrazine (2) towards some different reagents such as anhydride compounds, aromatic aldehydes, carb on disulphide, and nitrous acid yielded the corresponding pathalazine derivatives (3, 4, 5), hydrazone derivative (6), 1,3,4-oxadiazole derivative (7, 8, 9) and acid azide (10) respectively. Treatmen of 10 with absolute alcohols, amines and ethyl amino acid ester gave the corresponding carbamate derivative (11), substituted urea derivative (12) and ethyl substituted alkyl acetate (13) respectively. The biological activity of some synthesized compounds was evaluated.

• 한국자기공명학회논문지
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• 제11권1호
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• pp.1-9
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• 2007

An unequal site exchanging system induced by restricted rotation of 9-methyl group in 1,8-dichloro-9-triptycene has been studied by spin-lattice relaxation and 2D-EXSY experiments. The exchange rate obtained from relaxation studies is very well coincident to the result of line shape analysis, and the difference of the relaxation times ($T_1$) in two different sites has an important role to analyze 2D-EXSY experimental data.

• 대한방사성의약품학회지
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• 제6권2호
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• pp.69-74
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• 2020

PIB is the first amyloid plaque PET image tracer reported for the first time in 2003, and is considered to be the best and is still being utilized due to its very high uptake and kinetic properties. Initially, it was synthesized by radioisotope labeling using a precursor containing a methoxy methyl protection group, but now it is synthesized using a 6-OH precursor that can be easily synthesized in one step using [¹¹C]methyl triflate. Carbon-11 has several limitations in clinical studies using PET because its half-life is as short as 20 minutes. In this study, in order to overcome the difficulty of this half-life, a rapid method using Sep-Pak was adopted instead of HPLC purification to significantly reduce the burden of the purification process and attempted synthesis. As a result, the synthesis time was shortened by more than 50%, and the yield of the final compound was higher than the previous result and showed relatively high specific radioactivity, confirming that it is a strategic method with high applicability for various precursors having primary amines.

• 농약과학회지
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• 제10권4호
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• pp.306-312
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• 2006

시설하우스에서 방울토마토를 재배하여 농약 살포 후 경과일수별 세척시험을 실시하여 농약의 이화학적 특성별 세척에 의한 잔류농약의 제거율을 구하였다. 방울토마토에 3종의 시판농약을 살포한 후 수돗물로 세척한 결과 침투이행성 약제인 oxadixyl은 약제살포 후 0일에 61%, 5일에 11%, 7일에 4% 제거되었고 침투성약제인 thiophanate-methyl은 89%, 89%, 79%, 비침투성인 chlorothlaonil의 경우 84%, 84%, 88% 제거되었다. 세정제인 $Sur-ten^{(R)}$용액 세척시는 약제살포 후 0일과 5일에 oxadixyl 81%, 55%, thiophanate-methyl 95%, 91%, chlorothlaonil 97%, 98%가 각각 제거되었다. 제거율에 있어서 부성분의 영향을 평가하기 위해 시판농약과 달리 같은 부성분으로 제조된 시제품을 살포 한 후 수돗물 세척시에는 약제살포 후 0, 5, 7일에 각각 oxadixyl 76%, 66%, 43%, thiophanate-methyl 91%, 83%, 82%, chlorothlaonil 65%, 68%, 82% 제거되어 경과일수별 제거 양상은 시판농약과 비슷하였으나 제거율은 달라 세척시 원제 및 부성분함량의 영향이 있는 것으로 생각되었다.

• 한국식품과학회지
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• 제21권4호
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• pp.562-568
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• 1989

9월 중에 채취한 성숙한 초피 (Zanthoxylum piperitum DC)의 과피와 잎성분의 변성을 고려한 방법인 gas co-distillation으로 추출하고, GC/MS와 함께 workstation BASIC program들을 사용하여 극성이 다른 두 column(FFAP, HP-1)에 대한 authentic standard들의 retention index(RI) 값들을 구하여 HP-1 및 FFAP, RI reference library를 만든 후 초피의 정유성분들의 두 column library 탐색을 병행하여 분석함으로써, 과피에서 myrcene외 14 hydrocarbon들, linalool외 8 alcohol들, citronellal외 3 aldethyde들, carvone외 2 ketone들, methyl salicylate외 7 ester들 그리고 1,8-cineol 외 3 oxide를 확인하였고, 잎에서 limonene외 7 hydrocarbon들, citronellol외 7 alcohol들, cumin aldehyde외 1 aldehyde, carvone, 그리고 estragole외 1 oxide를 확인하였다. 과피에서는 1,8-cineol(25.47%), limonene(11.9%), geranylacetate(9.01%), myrcene(6.15%), geraniol(2.88%), citronellal(2.25%)등이 주성분이었고, 잎에서는 citronellal(23.11%), 1,8-cineol(18.38%), citronellol(6.04%), methyl cinnamate(4.08%)등이 주성분이었다.

• 농업과학연구
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• 제19권1호
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• pp.103-114
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• 1992

항산화성 생약을 선발하기 위하여 180종의 생약을 10배량의 methanol 로 추출한 액 $50{\mu}l$와 0.1M-linoleic acid ethanol 용액 $100{\mu}l$를 넣은 시험관을 $50^{\circ}C$에서 20시간 두었다가 POV를 측정하는 방법으로 항산화성을 측정하였을 때 45% 이상의 생약 추출물이 항산화성을 나타내었고 그 중 44종 의 생약추출물의 항산화성은 비교적 강력하였다. 단기 항산화시험에 의해서 항산화성이 비교적 강한 것으로 나타난 44종의 생약을 10배량의 methanol로 추출한액 3ml, 0.1M-methyl linoleate ethanol 용액 10ml 및 0.1M-sodium phosphate buffer(pH 7.0) 37ml를 혼합하여 $40^{\circ}C$에서 35일간 저장하면서 POV의 변화를 측정하였던 바 삼백초, 세신, 진범, 음양곽, 백굴체, 소회향, 고삼, 정향, 황금, 감초 및 파고지 동 11종의 생약추출물의 항산화성이 특히 강하였다. Methan이 추출액의 항산화성이 특히 강하였던 11종의 생약을 ethyl acetate 및 petroleum ether로 추출하여 항산화성을 비교하였을 때 음양곽, 소회향, 정향 및 파고지는 추출용매의 종류에 관계없이 강한 항산화성을 나타내었으나 황금 및 감초 등은 methanol 추출액에서만 강한 항산화능이 나타났다.

• Natural Product Sciences
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• 제11권3호
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• pp.179-182
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• 2005

We investigated that water extract of Acanthopanax sessiliflorus roots rescued the N-methyl-D-aspartate (NMDA), agonist of glutamate receptor, -induced toxicity in rat organotypic hippocampal slice culture. When the cell death in NMDA only-treated hippocampal slices was set 100%, A. sessiliflorus decreased the cell death to 75.4, 51.6, 48.9, and 40.6% at 1, 10, 50, and $100\;{\mu}g/ml$ treatment, respectively. On the basis of these results, the water extract of A. sessiliflorus roots may be a preventive agent against NMDA-induced cytotoxicity.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2711-2718
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• 2012

The alkylation of the ambident enolates of a methyl glycinate Schiff base with ethyl chloride was studied at B3LYP and MP2 levels with $6-31+G^*$ basis set. The free (E)-enolates and (Z)-enolate are similar in energy and geometry. The transition states for the alkylation of the free (E)/(Z)-enolate with ethyl chloride have similar energy barriers of ~13 kcal/mol. However, with a lithium ion, the (E)-enolate behaves as an ambident enolate and makes a cyclic lithium-complex in bidentate pattern which is more stable by 11-23 kcal/mol than the (Z)-enolate-lithium complexes. And the TS for the alkylation of (E)-enolate-lithium complex coordinated with one methyl ether is lower in energy than those from (Z)-enolate-lithium complexes by 4.3-7.3 kcal/mol. Further solvation model (SCRF-CPCM) and reaction coordinate (IRC) were studied. This theoretical study suggests that the alkylation of ambident enolates proceeds with stable cyclic bidentate complexes in the presence of metal ion and solvent.