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Nonvolatile Resistance Switching on Two-Dimensional Electron Gas
Joung, Jin Gwan,Kim, Shin-Ik,Moon, Seon Young,Kim, Dai-Hong,Gwon, Hyo Jin,Hong, Seong-Hyeon,Chang, Hye Jung,Hwang, Jin-Ha,Kwon, Beom Jin,Kim, Seong Keun,Choi, Ji-Won,Yoon, Seok-Jin,Kang, Chong-Yun,Yoo American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.20
<P>Two-dimensional electron gas (2DEG) at the complex oxide interfaces have brought about considerable interest for the application of the next-generation multifunctional oxide electronics due to the exotic properties that do not exist in the bulk. In this study, we report the integration of 2DEG into the nonvolatile resistance switching cell as a bottom electrode, where the metal–insulator transition of 2DEG by an external field serves to significantly reduce the OFF-state leakage current while enhancing the on/off ratio. Using the Pt/Ta<SUB>2</SUB>O<SUB>5–<I>y</I></SUB>/Ta<SUB>2</SUB>O<SUB>5–<I>x</I></SUB>/SrTiO<SUB>3</SUB> heterostructure as a model system, we demonstrate the nonvolatile resistance switching memory cell with a large on/off ratio (>10<SUP>6</SUP>) and a low leakage current at the OFF state (∼10<SUP>–13</SUP> A). Beyond exploring nonvolatile memory, our work also provides an excellent framework for exploring the fundamental understanding of novel physics in which electronic and ionic processes are coupled in the complex heterostructures.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-20/am504354c/production/images/medium/am-2014-04354c_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am504354c'>ACS Electronic Supporting Info</A></P>
건강기능식품 기능성 원료로서 곰취잎 추출물의 Caffeoylquinic Acid계 성분 분석법 검증
권진관(Jin Gwan Kwon),김진규(Jin Kyu Kim),서찬곤(Changon Seo),홍성수(Seong Su Hong),안은경(Eun-Kyung Ahn),서동완(Dong-Wan Seo),오좌섭(Joa Sub Oh) 한국식품영양과학회 2016 한국식품영양과학회지 Vol.45 No.1
본 연구는 HPLC를 이용해 개별 인정형 건강기능식품 원료로 개발하기 위하여 곰취잎 추출물의 지표성분인 CA, 3,4-DCQA, 3,5-DCQA 및 4,5-DCQA의 동시분석법 설정과 분석법에 대한 검증을 실시하고자 하였다. 그 검증의 결과 표준액과 곰취잎 추출물의 HPLC 크로마토그램을 비교하여 피크가 분리됨을 확인하고 다른 물질의 간섭 없이 분리되었으며, 표준액의 피크 유지시간과 추출물의 피크 유지시간이 일치하였고 동일한 spectrum을 나타내었다. 또한 blank에서 표준액과 겹치는 피크가 없는 것으로 특이성을 확인하였다. 검량선의 상관계수는 CA, 3,4-DCQA, 3,5-DCQA 및 4,5-DCQA 각각 0.9999, 0.9999, 0.9999 및 0.9999로 모두 양호한 직선성을 보였으며, 직선상의 검출한계는 3.0~13.2 μg/mL였으며 정량한계는 9.2~39.8 μg/mL로 나타났다. 곰취 추출물 0.6, 1.2 및 1.8 mg/mL의 세 농도의 회수율은 98.96~101.81%였으며 RSD는 0.14~0.89%로 나타나 RSD 2.0% 이하로서 정확성이 있음을 알 수 있었다. 정밀성은 0.04~0.51%의 정밀도를, 실험실 내 정밀성에서는 0.02 ~0.90%의 정밀도를 나타내었고 intra-day에서의 정밀도는 0.07~0.63%, inter-day에서는 0.39~0.66%의 정밀도를 나타내어 곰취잎 추출물의 지표성분 CA, 3,4-DCQA, 3,5-DCQA 및 4,5-DCQA의 분석법은 적합한 시험법임이 검증되었다. 본 분석법이 곰취 추출물 개별 인정형 건강기능식품원료 개발을 위한 기초자료로 활용될 것으로 사료된다. An HPLC analysis method was developed for standard determinations of chlorogenic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid as functional health materials in Ligularia fischeri extract. HPLC was performed on a C18 Kromasil column (4.6×250 mm, 5 μm column) with a gradient elution of 0.1% (v/v) trifluoroacetic acid and acetonitrile at a flow rate of 1.0 mL/min at 30°C. The analytes were detected at 330 nm. The HPLC method was validated in accordance with the International Conference on Harmonization guideline of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limits of detection and quantitation for the four compounds were 3.0∼14.6 and 9.2∼44.4 μg/mL, respectively. Calibration curves showed good linearity (r²>0.999), and the precision of analysis was satisfied (less than 0.9%). Recoveries of quantified compounds ranged from 98.96 to 101.81%. This result indicates that the established HPLC method is very useful for the determination of marker compounds in Ligularia fischeri leaf extracts.
HPLC 를 이용한 가는장구채 추출물의 Isoscoparin 분석법 개발
권진관 ( Jin Gwan Kwon ),서찬곤 ( Changon Seo ),정연우 ( Yeon Woo Jung ),최용문 ( Yongmun Choi ),신현탁 ( Hyun Tak Shin ),정수영 ( Su Young Jung ),최정준 ( Jeong June Choi ),김진규 ( Jin Kyu Kim ) 대한화장품학회 2021 대한화장품학회지 Vol.47 No.1
본 연구는 가는장구채(Silene seoulensis) 추출물을 기능성 화장품소재로 개발하기 위해 isoscoparin을 지표성분으로 선정하고, 품질관리를 위해 high performance liquid chromatography (HPLC)를 이용하여 분석법을 개발하였다. 분석용 칼럼은 Unison US-C<sub>18</sub>을, 이동상은 0.05% (v/v) trifluoroacetic acid (TFA)와 메탄올을 사용하여 컬럼 온도는 35 ℃ 에서 유속 1.0 mL/min 로 검출파장은 330 nm에서 검출하였다. International conference on harmonization (ICH) 가이드라인(version 4, 2005)을 근거로 하여 특이성, 직선성, 정밀성, 정확성, 검출한계 및 정량한계를 분석하여 분석방법을 검증하였다. 분석결과, 검출한계 및 정량한계는 0.02 및 0.07 mg/mL로 나타났으며, 검량곡선은 상관계수 값이 0.99988로 양호한 직선성을 보였고 정밀성 분석결과도 0.46% 이하로 확인되었다. 또한, 회수율은 99.10 ~ 101.61% 범위로 정확성이 있음을 확인하였다. 따라서, 본 분석법은 가는장구채 추출물 지표성분의 분석법으로 적합한 시험법임이 검증되었다. In this study, isoscoparin was selected as an indicator component to develop Silene seoulensis extract as a functional cosmetic material, and we developed an analysis method using high performance liquid chromatography (HPLC) for quality control. HPLC was performed on a Unison US-C<sub>18</sub> with a gradient elution of 0.05% (v/v) trifluoroacetic acid (TFA) and methanol at a flow rate of 1.0 mL/min at 35 ℃, and the detection wavelength was 330 nm. The HPLC method was performed in accordance with the international conference on harmonization (ICH) guideline (version 4, 2005) of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limits of detection and quantitation were 0.02 and 0.07 mg/mL respectively. Calibration curves showed good linearity (R2 > 0.99988), and the precision of analysis was satisfied (less than 0.46%). In addition, the recovery rate was in the range of 99.10 to 101.61%, it was shown to be accurate. This result indicated that the established HPLC method is very useful for the determination of marker compounds in Silene seoulensis extracts.