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Formation and Annealing Effect of Tolanethioacetate Self-Assembled Monolayers on Au(111)
Youngdo Jeong,한진욱,Nakjoong Kim,Youngil Lee,이창진,Masahiko Hara,노재근 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.12
Self-assembled monolayers (SAMs) were formed by adsorption of thioacetyl-terminated tolanethioacetate (TTA) on Au(111) in a 0.5-mM ethanol solution after one day immersion at room temperature. Molecular-scale STM imaging revealed that the TTA SAMs were composed of two mixed phases; an ordered phase with small domains describing a ( 2)R30 structure and a disordered phase. Interestingly, after annealing the pre-covered TTA SAMs on Au(111) at 90 C for 1 h, the small ordered domains grew unidirectionally, resulting in the formation of unique rod-like domains, which were assigned a ( 2)R7 structure. These results will be very useful in understanding the formation and thermal behavior of TTA SAMs on gold surfaces.
Jeong, YoungDo,Lee, Young Jun,Kwon, Deuk-Chul,Lee, Sang-Jin,Jeon, Jae-Hong,Seo, Jong Hyun,Tong, Lizhu,Choe, HeeHwan American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.11
<P>A plasma simulation based on a fluid model is conducted for capacitively-coupled plasma (CCP), which is used for thin-film transistor fabrication in display devices. A two-dimensional cross section of a process chamber is used in the simulation. Simulation results were compared with those of a 1D simulation method. The plasma characteristics were investigated using several process conditions such as applied voltage and pressure.</P>
Jeong Rim Kim,Youngdo Won 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.12
Quantitative structure activity relationship has been probed for spirosuccinimide-fused tetrahydropyrrolo[1,2- a]pyrazine-1,3-dione derivatives acting as aldose reductase inhibitors. While the spirosuccinimide compounds contain a chiral center, the aldose reductase inhibition assay was performed with racemic mixtures in the published work. As the physicochemical descriptors of the QSAR analysis must be evaluated for a definite molecular structure, we devise a new “racemic” descriptor as the arithmetic mean of the (R)-enantiomer descriptor and the (S)-enantiomer descriptor. The resultant QSAR model derived from the racemic descriptors outperforms the original QSAR models, closely reproducing the observed activity of optically pure enantiomers as well as racemic mixtures.
손정매(Jeong-Mae Son),유승현(Seunghyun Yoo),이상준(Sangjun Lee),신지훈(Jihoon Shin),정근우(Kunwo Chung),양영도(Youngdo Yang),김영운(Young-Wun Kim) 한국트라이볼로지학회 2014 한국윤활학회지(윤활학회지) Vol.30 No.5
Enhancing the value of fine chemicals based on biomass resources is an important objective for addressing environmental and other concerns such as demand for renewable or green products, as well as from the political perspective to reduce dependence on fossil feedstock associated with the use of petroleum-based products. Based on these considerations, we studied the synthesis of estolide using waste plant-based oil materials and their application as lubricants and pour point depressants. Five estolides were prepared by varying molar ratio of palmitic acid (PA) to oleic acid (OA) using a reaction time of 48 h. The estolides were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR). The isolated yields were in the range of 57-78 % and purity was 93-97%, showing iodine values of 18.2-37.8, total acid numbers (TANs) of 75.6-94.2 mg KOH/g and estolide numbers (ENs) of 1.2-1.8. Increasing the ratio of OA to PA in the synthesis decreased the kinematic viscosity and clouding point of the estolides. Four ball wear test of the estolides as a base oil demonstrated that the wear scar diameter (WSD) of the estolides was significantly lower (0.320-0.495 mm) than the WSD of general base oils such as 150N and Yubase (0.735 and 0.810 mm, respectively), indicating better wear resistance of the estolides. However, the lubricant property was found to be independent of the amount of OA in the estolides. These new materials are prospective candidates for application as a lubricant base oil.
손정매(Jeong-Mae Son),김남균(Nam-Kyun Kim),신지훈(Jihoon Shin),양영도(Youngdo Yang),김영운(Young-Wun Kim) 한국트라이볼로지학회 2015 한국트라이볼로지학회 학술대회 Vol.2015 No.10
Heavy oil production has received significant attention due to the increase in demand for thermal power generation system of the diesel engine and boiler. However, asphaltene, which is one of heavy oil components (6-8wt %), reduces the heat efficiency of the fuel owing to the aggregate sludge of asphaltene during burning process. The development of asphaltene dispersants for the trouble-free operation should be carried out to suppress the formation of the sludge. We prepared variable polymeric dispersants with salt type using poly(isobutenylsuccinic anhydride) and poly(amines), which was subsequently evaluated for dispersing performance, using Tubiscan measurement. Total acid number (TAN) and total base number(TBN) of 75Lec-25SynDis.2 composed of lecithin and the polymeric salt having a ratio of 3 to 1 were 18.9 and 33.7 mg KOH/g, which were comparable to those of the conventional dispersant (Nippon Yuka Co.) (15.8 and 26. mg KOH/g), respectively. The initial turbidity observed for 15 min of the polymeric dispersant could be calculated to separability number, resulting in values near zero, which was superior to 0.3 to 0.9 of the commercial dispersants.
Finding communities in directed networks.
Kim, Youngdo,Son, Seung-Woo,Jeong, Hawoong Published by the American Physical Society through 2010 Physical review. E, Statistical, nonlinear, and so Vol.81 No.1
<P>To identify communities in directed networks, we propose a generalized form of modularity in directed networks by presenting the quantity LinkRank, which can be considered as the PageRank of links. This generalization is consistent with the original modularity in undirected networks and the modularity optimization methods developed for undirected networks can be directly applied to directed networks by optimizing our modified modularity. Also, a model network, which can be used as a benchmark network in further community studies, is proposed to verify our method. Our method is supposed to find communities effectively in citation- or reference-based directed networks.</P>
손정매(Jeong-Mae Son),김남균(Nam-Kyun Kim),신지훈(Jihoon Shin),양영도(Youngdo Yang),김영운(Young-Wun Kim) 한국트라이볼로지학회 2015 한국윤활학회지(윤활학회지) Vol.31 No.6
Heavy oil production is receiving significant attention because of increased demands for thermal power generation systems of the diesel engine and boilers. However, asphaltene, which is a heavy oil components (6-8 wt%), reduces the heat efficiency of the fuels owing to its agglomerated sludge of asphaltene during the burning process. Therefore, for hassle-free operation, we should develop asphaltene dispersants to suppress the formation of the sludge. We prepare variable salt-type polymeric dispersants using poly(isobutenyl succinic anhydride) and poly(amine) through both condensation esterification and acid-base neutralization reactions, which we subsequently evaluate for dispersing performance, using Turbiscan measurement. Total acid number (TAN) and total base number (TBN) of 75Lec-25SynDis.2 composed of lecithin and the prepared polymeric salt having the ratio of 3 : 1 are 18.9 and 33.7 mg KOH/g, respectively, which are comparable to those of the commercial dispersants (15.8 and 26.5 mg KOH/g). We determine the initial turbidity observed for 15 min of the polymeric dispersant was determined with transmittance (%), which can be calculated to separability number (SN). The SN value of 75Lec-25SynDis.2 is close to zero, which is superior to that of commercial dispersants and lecithin (0.015 and 0.017).
On the Estimation of Heritability with Family-Based and Population-Based Samples
Kim, Youngdoe,Lee, Young,Lee, Sungyoung,Kim, Nam Hee,Lim, Jeongmin,Kim, Young Jin,Oh, Ji Hee,Min, Haesook,Lee, Meehee,Seo, Hyeon-Jeong,Lee, So-Hyun,Sung, Joohon,Cho, Nam H.,Kim, Bong-Jo,Han, Bok-Ghee Hindawi Publishing Corporation 2015 BioMed research international Vol.2015 No.-
<P>For a family-based sample, the phenotypic variance-covariance matrix can be parameterized to include the variance of a polygenic effect that has then been estimated using a variance component analysis. However, with the advent of large-scale genomic data, the genetic relationship matrix (GRM) can be estimated and can be utilized to parameterize the variance of a polygenic effect for population-based samples. Therefore narrow sense heritability, which is both population and trait specific, can be estimated with both population- and family-based samples. In this study we estimate heritability from both family-based and population-based samples, collected in Korea, and the heritability estimates from the pooled samples were, for height, 0.60; body mass index (BMI), 0.32; log-transformed triglycerides (log TG), 0.24; total cholesterol (TCHL), 0.30; high-density lipoprotein (HDL), 0.38; low-density lipoprotein (LDL), 0.29; systolic blood pressure (SBP), 0.23; and diastolic blood pressure (DBP), 0.24. Furthermore, we found differences in how heritability is estimated—in particular the amount of variance attributable to common environment in twins can be substantial—which indicates heritability estimates should be interpreted with caution.</P>