http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Polarizability of Carbon Nanotube Peapods from First-Principles
Kiseok Chang,윤영귀 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.3
Carbon nanotube peapods have been suggested as nanoelectronic devices, such as bucky shuttle memories and three-terminal switching devices. However, relevant physical properties are not fully understood. We calculate the polarizability of carbon nanotube peapods from first-principles. We obtain a substantial reduction in the polarizability of an endohedral C60 moledule in various carbon nanotube peapod structures. The reduction depends on the structures and the directions of the external electric fields. The features of polarizability will be important in device applications of carbon nanotube peapods.
실시간 리눅스 기반의 회전익 무인항공기 제어 소프트웨어 개발
박기석 ( Kiseok Park ),박중희 ( Joong Hee Park ),위영준 ( Young Jun Wie ),박정근 ( Jungkeun Park ),문창주 ( Chang Joo Moon ) 한국정보처리학회 2010 한국정보처리학회 학술대회논문집 Vol.17 No.2
본 논문은 실시간 운영체제인 Xenomai 를 사용하여, 회전익 무인항공기 소프트웨어 개발에 대한 내용을 설명하고 있다. 실시간 운영체제 사용하여 고정 순위 우선 스케줄링을 채택함으로써 데드라인의 타이밍(Timming) 결정성을 보장하였고, 이기종 시스템과의 호환성과 확장성을 고려하여 POSIX API 를 사용하여 멀티 쓰레드를 구현하였다. 또한 실시간 드라이버 모델(RTDM : Real-Time Driver Model)을 사용하여 획득한 데이터를 실시간 전송이 가능하도록 하였다. 본 논문은 실시간 운영체제를 무인항공기에 적용하고 구현된 비행제어 컴퓨터와 제어 소프트웨어를 비율 단조 스케줄링을 적용하여 무인항공기의 쓰레드들의 응답 속도 및 안정성을 보장하는 방안을 제시하였다.
Cooperative upconversion and optical gain in ion-beam sputter-deposited Er_xY_2-xSiO_5 waveguides
Suh, Kiseok,Lee, Minkyung,Chang, Jee Soo,Lee, Hansuek,Park, Namkyoo,Sung, Gun Yong,Shin, Jung H. The Optical Society 2010 Optics express Vol.18 No.8
<P>Single-phase, polycrystalline Er(x)Y(2-x)SiO(5) thin films were deposited by reactive ion-beam sputter deposition and rapid thermal annealing. Due to the crystalline nature, the silicate thin films provide peak Er(3+) emission cross-section of 0.9 +/- 0.02 x 10(-20) cm(2) that is higher than that in silica. Optical gain, with near 60% inversion, is achieved via optical pumping of a single-mode, ridge-type waveguide with the silicate core with an Er concentration of 1.7 x 10(20) cm(-3). Analysis of pump-power dependence of the optical gain and spontaneous emission intensity of Er(3+) indicate that the gain is limited by cooperative upconversion process, whose coefficient is determined to be (8 +/- 3) x 10(-17) cm(3)/sec.</P>
SYNTHESIS OF DIPHENYLAMINE DERIVATIVES ON Pd/C CATALYST
Lee, Tae Jin,Kim, Kiseok,Kim, Byong Sam,Jung, Dong Geun,Kim, Jae Chang,Kim, Dong Hyun 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.5
2-Methyl-3¹-hydroxydiphenylamine was synthesized from the mixture of 3-aminophenol, 3-nitrophenol, and 2-methylcyclohexanone in the presence of Pd/C catalyst. The optimum composition of the reaction mixture was determined for maximum yield of the diphenylamine derivative : with the molar ratio of 3-aminophenol : 3-nitrophenol fixed at 1 mnol : 2 mmol, the relative molar amounts of 2-methylcyclohexanone were varied between 3 and 96. At the optimum composition the amounts of Pd/C catalyst were varied threefold in order to investigate the effect of Pd on the product yield. The, results abtained from the reaction mixture containing 1 mmol of 3-aminophenol were satisfactorily reproduced for the reaction mixture containing more than 10 mmol of 3-aminophenol. The formation of this diphenylamine derivative could be interpreted using the mechanism for the catalytic synthesis of 2-methyl-4-methoxydiphenylamine which we had optimized previously.
( Ho Hyun Nam ),( Dae Won Jun ),( Kiseok Jang ),( Joo Hyun Sohn ),( Jae Yoon Jeong ),( Chang Hong Lee ),( Waqar Khalid Saeed ),( Jai Sun Lee ),( Hyeon Tae Kang ),( Yeon Ji Chae ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1
Aims: Protective effects of granulocyte colony stimulating factor (G-CSF) on nonalcoholic fatty liver disease (NAFLD) have been reported in animal models. However, the therapeutic effect of G-CSF has been suggested via marrow stem cell mobilization. We investigated the direct effect of G-CSF on hepatocytes in NAFLD. Methods: G-CSFr expression was evaluated in various liver disease model (NAFLD, alcoholic hepatitis, toxic hepatitis, chronic liver disease model). Two kinds of NAFLD models (high fat (HF), methionine choline deficient (MCD)) were used. In HF model included five arms as follows: control, HF, and three HF+G-CSF (30μg/kg, i.p) treatment groups (G1, G-CSF once weekly from 8th~12th week; G2, once daily for 5 days only in 9th week; G3, twice weekly from 9th to 12th week). In MCD model, four groups were included as follows; control, MCD, short and long acting G-CSF were tested. Long acting G-CSG was injected once a month. For in vitro experiments, the HepG2 cells were treated with palmitic acid (PA) 400μM, oleic acid (OA) 800μM, and G-CSF 100ng/ml. Cell viability (MTT) and oxidative stress (ROS), G-CSF receptor (IF, RT-PCR) were also measured. Results: The G-CSFr expression increased significantly in HF (14.7 times), alcohol hepatitis (7.1 times), chronic thioacetamide (TAA) (2.4 times), and ischemia reperfusion (IR) (6.8 times) groups as compared to the control. In HF induced NAFLD model, G-CSF treatment did not decrease the body weight compared to control groups. Continuous low dose group which can’t mobilize marrow stem cell (G3 group) showed significantly reduced intrahepatic fat accumulation as well as liver chemistry compare to HF induced NAFLD model without changing of body weight and liver to body weight ratio. Low dose long acting G-CSF with once a month injection also improved intrahepatic fat amount as well as degree of intrahepatic inflammation. Low dose long acting G-CSF treatment reduced the mRNA expression for hepatic de novo triglycerides synthesis (SREBP1c, FAS, SCD-1), cholesterol synthesis (SREBP2, HMG-CoA reductase) and inflammatory markers (MCP-1 TNF-a). G-CSF treatment increased cell proliferation markers (p-PI3 kinase, p-Akt), while decreased apoptosis in MCD diet groups. In Vitro results as follows; G-CSF+PA treatment increased cell viability in both 24h, and 48h treated groups. ROS was also significantly reduced in G-CSF group. Cell viability increased G-CSF group but decreased in G-CSF+PI3 kinase inhibitor and PI3 kinase inhibitor alone groups. Similarly, ROS decreased G-CSF but increased in G-CSF+PI3 kinase inhibitor and PI3 kinase inhibitor alone groups. Conclusions: G-CSF receptor expression in Hepatocytes in various NAFLD model and G-CSF administration of low-density low-frequency improves HF model and long acting G-CSF improves MCD model.
Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles
Lee, Hye-Eun,Ahn, Hyo-Yong,Mun, Jungho,Lee, Yoon Young,Kim, Minkyung,Cho, Nam Heon,Chang, Kiseok,Kim, Wook Sung,Rho, Junsuk,Nam, Ki Tae Nature Publishing Group UK 2018 Nature Vol.556 No.7701
<P>Understanding chirality, or handedness, in molecules is important because of the enantioselectivity that is observed in many biochemical reactions(1), and because of the recent development of chiral metamaterials with exceptional light-manipulating capabilities, such as polarization control(2-4), a negative refractive index(5) and chiral sensing(6). Chiral nanostructures have been produced using nanofabrication techniques such as lithography(7) and molecular self-assembly(8-11), but large-scale and simple fabrication methods for three-dimensional chiral structures remain a challenge. In this regard, chirality transfer represents a simpler and more efficient method for controlling chiral morphology(12-18). Although a few studies(18,19) have described the transfer of molecular chirality into micrometre-sized helical ceramic crystals, this technique has yet to be implemented for metal nanoparticles with sizes of hundreds of nanometres. Here we develop a strategy for synthesizing chiral gold nanoparticles that involves using amino acids and peptides to control the optical activity, handedness and chiral plasmonic resonance of the nanoparticles. The key requirement for achieving such chiral structures is the formation of high-Miller-index surfaces ({hkl}, h not equal k not equal l not equal 0) that are intrinsically chiral, owing to the presence of 'kink' sites(20-22) in the nanoparticles during growth. The presence of chiral components at the inorganic surface of the nanoparticles and in the amino acids and peptides results in enantioselective interactions at the interface between these elements; these interactions lead to asymmetric evolution of the nanoparticles and the formation of helicoid morphologies that consist of highly twisted chiral elements. The gold nanoparticles that we grow display strong chiral plasmonic optical activity (a dissymmetry factor of 0.2), even when dispersed randomly in solution; this observation is supported by theoretical calculations and direct visualizations of macroscopic colour transformations. We anticipate that our strategy will aid in the rational design and fabrication of three-dimensional chiral nanostructures for use in plasmonic metamaterial applications.</P>