Current-carrying capacity of double-wall carbon nanotubes

Moon, Sunkyung,Song, Woon,Kim, Nam,Sung Lee, Joon,Na, Pil Sun,Lee, Soon-Gul,Park, Jongwan,Jung, Myung-Hwa,Lee, Hyun-Woo,Kang, Kicheon,Lee, Cheol Jin,Kim, Jinhee IOP Pub 2007 Nanotechnology Vol.18 No.23

<P>We have studied electrical transport characteristics of individual double-wall carbon nanotubes (DWNT) under high bias voltages. As the bias voltage applied to the carbon nanotubes increases, the outermost shell of the DWNTs broke down sequentially, which enabled us to determine the current-carrying capacity of each shell. The maximum current-carrying capacity per shell was about 150 µA, which is well above that of any other previous reports. </P>

Local-Gating Carbon-Nanotube Transistor with Poly-Si Bottom Gates

송운,Sunkyung Moon,이순걸,김진희 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.4

A carbon nanotube field-effect transistor (CNFET) over poly-Si local gates was fabricated. The highly-doped poly-Si local gates were fabricated on top of a SiO2 layer and an individual single-wall carbon nanotube was grown over the ploy-Si gates by using chemical vapor deposition. The transport characteristics of the CNFETs were measured at low temperatures. The gate response showed typical p-type FET characteristics with both global back and local bottom gates. The gate coupling of the local gates were comparable to or even greater than that of the global back gate. By applying appropriate gate bias voltages, we could achieve complete depletion of the carriers in the conduction channel.

의료취약 지역의 응급환자를 위한 확장현실 기반 원격의료 기술 동향

김선경(Sunkyung Kim),최종명(Jongmyung Choi),문지현(Ji Hyun Moon),최소은(So-Eun Choi),이영호(Youngho Lee) 한국정보과학회 2020 정보과학회지 Vol.38 No.5

고품질화 바이오가스 이용 기술지침 마련을 위한 연구(Ⅱ): 도시가스 및 수송용 - 정밀모니터링 결과 중심으로

문희성(HeeSung Moon),권준화(Junhwa Kwon),박호연(Hoyeon Park),전태완(Taewan Jeon),신선경(Sunkyung Shin),이동진(Dongjin Lee) 유기성자원학회 2019 유기물자원화 Vol.27 No.2

본 연구는 유기성폐자원(가축분뇨, 음식물류폐기물, 음식물류폐수 등)의 바이오가스 이용에 대한 적정 설계 및 운전 기술지침서 마련하고자 현장조사와 정밀모니터링 등을 실시하였다. 정부의 중장기 바이오가스화 정책에 따라 폐자원의 자원화 시설 확충이 활발히 추진되고 있다. 하지만 생산된 바이오가스를 이용하여 도시가스 및 수송용으로 활용하는 시설은 효율이 아직은 저조하다. 전국 7개소 유기성폐자원 바이오가스화 시설을 대상으로 정밀모니터링을 실시하였다. 사계절 평균으로 정밀모니터링 결과를 정리하였을 때, 유기성폐자원 별 효율성 분석에 서 유기성분해율은 VS기준 평균 66.3%로 분석되었다. 전처리 전후 바이오가스 성상을 분석한 결과 철염 및 탈황(건식, 습식)을 이용하여 전체 시설의 H2S 평균은 949.7 ppm으로 측정되었으며, 고품질화 정제설비 전단 및 후단에서 29.0 ppm과 0.3 ppm으로 나타났다. 메탄 함량은 소화조 후단에서 65.6%, 고품질화 정제설비 전단 및 후단에서 63.5 %와 97.5 %까지 감소하는 것을 확인하였다. This study carried out on-site investigation and precision monitoring to prepare proper design and operation technical guidelines for the use of bio gas in organic waste resources (fertilizing urine, food waste, food waste, food waste, etc.). According to the government s mid- and long-term policy on bio gasification, the expansion of waste resources is actively being pushed forward. However, facilities that use the biogas produced for urban gas and transportation are still under-efficient. Precision monitoring was carried out for biogasification facilities of organic waste resources in seven locations nationwide. When the results of precision monitoring were summarized with the four-season average, the efficiency analysis of each organic waste resource showed that the organic breakdown rate was 66.3% on average on VS basis. Analysis of biogas characteristics before and after pretreatment revealed that the H 2 S average of the entire facility was measured at 949.7 ppm using iron salts and desulfurization (dry, wet) and that the quality refining facility shearing and rear end was 29.0 ppm and 0.3 ppm. The methane content was found to be reduced by 65.6% at the rear of the fire tank, 63.5% at the back and 97.5% at the rear.

간호대학생에 대한 웰다잉 교육프로그램의 효과

문현정,차선경,정성원,Moon, Hyunjung,Cha, Sunkyung,Jung, Sungwon 한국호스피스완화의료학회 2015 한국호스피스.완화의료학회지 Vol.18 No.3

Purpose: We examined the effects of a well-dying program on nursing students in terms of death preparation, death recognition and perception of well-dying perception. Methods: The design of this study was quasi-experimental and non-synchronized with a non-equivalent control group. The study was conducted with nursing students: 32 in the experimental group and 36 in the control group. The well-dying program was consisted of five sessions: introduction, thinking about meaning of death, organizing things to do before dying, looking back on my life, and leaving a trail of my life. Descriptive analysis, t-test, ${\chi}^2$ test and ANCOVA were used with SPSS 18.0 program to analyze the data. Results: After attending the program, a difference was observed in death preparation of the experimental group (t=2.61, P=0.014). The death recognition (F=154.15, P<0.001) score of the experimental group was significantly higher than the control group. There was no significant difference between the groups in perception of well-dying (F=0.11, P=0.747). Conclusions: The well-dying program helped nursing students build positive death recognition. Therefore, this study is expected to contribute to development of a death education program for nursing students. 목적: 본 연구는 웰다잉 교육프로그램이 간호대학생의 죽음준비와 죽음 및 웰다잉에 대한 인식에 미치는 효과를 확인하기 위하여 실시되었다. 방법: 연구설계는 비동등성 대조군 사전-사후 설계의 유사실험 연구였다. 대상자는 간호대학생으로서 실험군 32명, 대조군 36명이었다. 웰다잉 교육프로그램은 1회에 90~150분씩, 프로그램 소개와 죽음의 의미 탐색, 사망전 정리해야 할 일, 장례준비, 유언장 작성 등 5회에 걸쳐 워크숍으로 진행되었다. 수집된 자료는 SPSS Win 18.0 프로그램을 이용하여 t-test, ${\chi}^2$ test, paired t-test와 ANCOVA로 분석하였다. 결과: 웰다잉 교육프로그램을 적용한 중재 전 후에 실험군의 죽음준비인식이 통계적으로 유의하게 증가하였고(t=2.61, P=0.014), 중재 후 실험군의 죽음에 대한 인식은 대조군보다 유의하게 증가하였다(F=154.15, P<0.001). 그러나 웰다잉 인식에서는 유의한 차이가 없었다. 결론: 이상의 결과로 볼 때 죽음에 대한 체험을 바탕으로 한 워크숍 형태의 웰다잉 교육프로그램은 간호대학생의 웰다잉 인식에는 효과가 없었으나 죽음준비인식과 죽음에 대한 인식을 긍정적으로 변화시키는 것으로 나타나 죽음과 관련된 인식을 높이는 데에 도움이 되는 중재로 활용될 수 있다고 판단된다.

Short-channel effect and single-electron transport in individual indium oxide nanowires

Jung, Minkyung,Lee, Hyoyoung,Moon, Sunkyung,Song, Woon,Kim, Nam,Kim, Jinhee,Jo, Gunho,Lee, Takhee IOP Pub 2007 Nanotechnology Vol.18 No.43

<P>We have investigated the electric transport properties of individual In<SUB>2</SUB>O<SUB>3</SUB> nanowire devices. We have found that the gate modulation characteristics depend strongly on the channel length. If the channel length is greater than 450 nm, the gate modulation curve exhibited field-effect transistor behavior with dominant n-channel current at room temperature. With the decrease of the channel length, the leakage current is increased due to the short-channel effect. For such short-channel devices, the gate modulation curve exhibited quasi-periodic current oscillations at low temperature, which are attributed to the Coulomb blockade of single-electron tunneling. Some devices showed two-fold periodicity in the Coulomb diamonds which may arise from the spin degeneracy of the single-particle energy levels.</P>

Protective Effect of KR-31378 on Oxidative Stress in Cardiac Myocytes

Kim Mi-Young,Lee Sunkyung,Yi Kyu Yang,Yoo Sung Eun,Lee Dong-Ha,Lim Hong,Kim Ho Soon,Lee Soo Hwan,Baik Eun Joo,Moon Chang-Hyun,Jung Yi-Sook The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.12

In this study, we investigated whether a novel anti-ischemic $K_{ATP}$ opener KR-31378 [(2S,3S,4R)­N'-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2 -methly-2-dimethoxymethly-2H-benzopyran-4-yl)­N'-benzylguanidine] has protective effect against oxidative stress-induced death in heart-derived H9c2 cells. Cell death was induced by BSO, butionine sulfoximine, which inhibits GSH synthesis and subsequently increases reactive oxygen species (ROS) level. Cell death was quantitatively determined by measuring lactate dehydrogenase (LDH) activity and stained by Hoechst 33258. BSO-induced ROS production and mitochondrial membrane potential (MMP) were measured using 2',7'-dichlorofluorescein diacetate oxidation and rhodamine 123, respectively. Both the LDH release and the ROS elevation induced by treatment of H9c2 cells with 10 mM BSO, were significantly decreased by KR-31378. These protective effect and antioxidant effect of KR-31378 appeared to be independent on $K_{ATP}$ channel opening. Cells exposed to BSO showed an early reduction in MMP, and this reduction in MMP was significantly reversed by treatment with KR-31378. Caspase-3 activity in BSO treated H9c2 cells was remarkably increased, and this increased caspase-3 activity was significantly reversed by KR-31378. In conclusion, our results suggest that KR-31378 can produce cardioprotective effect against oxidative stress-induced cell death through antioxidant mechanism.

KR-32570, a novel Na⁺/H⁺ exchanger-1 inhibitor, attenuates hypoxia-induced cell death through inhibition of intracellular Ca²⁺ overload and mitochondrial death pathway in H9c2 cells

Kim, Mi Jeong,Moon, Chang-Hyun,Kim, Mi-Young,Lee, Sunkyung,Yi, Kyu Yang,Yoo, Sung Eun,Lee, Soo Hwan,Baik, Eun Joo,Jung, Yi-Sook Elsevier 2005 european journal of pharmacology Vol.525 No.1

<P><B>Abstract</B></P><P>A novel Na<SUP>+</SUP>/H<SUP>+</SUP> exchanger-1 (NHE-1) inhibitor [5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl]guanidine (KR-32570) has been previously demonstrated to elicit cardioprotective effect against ischemic injury in rat heart. In the present study, we examined the effects of KR-32570 on cell death induced by hypoxic insult in heart-derived H9c2 cells. Treatment with KR-32570 (1–10 μM) significantly reduced hypoxia-induced necrotic cell death (lactate dehydrogenase release) and apoptotic cell death (TUNEL-positivity, caspase-3 activity). KR-32570 also decreased the cytosolic and mitochondrial Ca<SUP>2+</SUP> overload induced by hypoxia. Inhibition of mitochondrial Ca<SUP>2+</SUP> overload by ruthenium red mimicked the anti-apoptotic effect of KR-32570. In addition, KR-32570 significantly recovered the large reduction in mitochondrial membrane potential (Δ<I>Ψ</I><SUB>m</SUB>) and cytochrome <I>c</I> release induced by hypoxia. Taken together, our results suggest that a new NHE-1 inhibitor KR-32570 elicits potent cardioprotective effects in H9c2 cells, and its effects may be mediated by inhibition of intracellular Ca<SUP>2+</SUP> overload and mitochondrial death pathway during hypoxia.</P>

Pharmacokinetics of a novel antiangiogenic agent KR-31831 in rats

Kim, Sook J.,Lee, Hong I.,Ji, Hye Y.,Moon, Ya,Paek, In B.,Lee, Sunkyung,Yi, Kyu Y.,Yoo, Sun D.,Lee, Hye S. John Wiley Sons, Ltd. 2005 Biopharmaceutics and Drug Disposition Vol.26 No.1

<P>This study reports the absorption, dose-linearity and pharmacokinetics of a novel antiangiogenic agent KR-31831 in rats after i.v. and oral administration at doses of 5, 10 and 25 mg/kg on both occasions. Concentrations of KR-31831 were determined by a validated LC/MS/MS assay method. After i.v. injection, plasma concentration-time profiles showed multi-compartmental characteristics, and there were no significant differences in Cl (20.8–27.7 ml/min/kg) and dose-normalized AUC (178.1–231 µg·min/ml based on the 5 mg/kg dose) as a function of dose. However, V<SUB>ss</SUB> was significantly increased at the 25 mg/kg dose (4931 ml/kg) compared with those (2288–2421 ml/kg) at lower doses. Subsequently, t<SUB>1/2</SUB> was increased from 143–159 min at the lower doses to 304 min at the 25 mg/kg dose. The altered V<SUB>SS</SUB> was found to be a result of reduced plasma protein binding at relatively high concentrations. Following oral administration (doses 5–25 mg/kg), the absolute oral bioavailability ranged from 37.8% to 46.3%, and there were no significant alterations in dose-normalized AUC, T<SUB>max</SUB>, C<SUB>max</SUB> and t<SUB>1/2</SUB> as a function of dose. The extent of urinary excretion was low for both i.v. (0.35%–0.54%) and oral (0.13%–0.33%) doses. Further discussions on the chemical and microsomal stability were included. In conclusion, dose-independent absorption kinetics were observed at oral doses from 5 to 25 mg/kg in rats. Orally administered KR-31831 could be eliminated mainly by the liver metabolic pathway. Copyright © 2004 John Wiley & Sons, Ltd.</P>

The Formation of $YBa_2$$Cu_3$$O_7$ Step-edge Josephson Junction on LaAl$O_3$and MgO Single Crystal Substrates by Using Step-edge Annealing

황윤석,김진태,문선경,이순걸,박용기,박종철,Yunseok Hwang,Kim, Jin-Tae,Sunkyung Moon,Lee, Soon-Gul,Park, Yong-Ki,Park, Jong-Chul 한국초전도학회 2001 Progress in superconductivity Vol.2 No.2

The effect of annealing step-edges of LaAlO$_3$ and MgO single crystal substrates on YBa$_2$Cu$_3$O$_{7}$ junction has been studied. The step-edge was fabricated by argon ion milling and was annealed at 105$0^{\circ}C$ in 1 attn oxygen pressure. We compared AFM image near step-edge of the substrates between before and after annealing process. And YBa$_2$Cu$_3$O$_{7}$ thin film was deposited on the step-edge by a standard pulsed laser deposition. The step-edge junctions were characterized by current-voltage curves at 77 K. The annealing of step-edges of MgO substrate improved the current-voltage characteristic of Josephson junction: double steps in the current-voltage characteristic disappeared. However the annealing for LaAlO$_3$ did not improve the junction property.rty.