Drop impact on microwetting patterned surfaces (7 pages)

Lee, M.,Chang, Y.S.,Kim, H.-Y. AMERICAN INSTITUTE OF PHYSICS 2010 Physics of Fluids Vol.22 No.7

Enzymatic Biodiesel Synthesis in Semi-Pilot Continuous Process in Near-Critical Carbon Dioxide

Lee, M.,Lee, D.,Cho, J.,Kim, S.,Park, C. HUMANA PRESS INC 2013 Applied biochemistry and biotechnology Vol.171 No.5

The adsorption selectivity of the functional groups of dithiothreitol and 1,4-butanedithiol 2,3-diamino on the Ge(100) surface

Lee, M.,Park, Y.,Lee, H. North Holland ; Elsevier Science Ltd 2013 Chemical physics letters Vol.567 No.-

The adsorption selectivities between dithiothreitol (DTT) and 1,4-butanedithiol 2,3-diamino (BDD) were revealed through density functional theory (DFT) calculations. DFT calculations predict that DTT does not stably adsorb onto the Ge(100) surface because both hydroxyl and thiol group in DTT serve as similar nucleophilic groups, therefore they are not selective. However, BDD is predicted to adsorb stably onto the Ge(100) surface because the amine and thiol groups in BDD operate relatively different nucleophilic group, and it is selective. The adsorption energies of BDD onto the Ge(100) surface suggested that an S-H dissociated N2-H dissociation bonded structure is the most stable structure.

Conformational sampling of metastable states: Tq-REM as a novel replica exchange method

Lee, M.,Yoon, J.,Jang, S.,Shin, S. Royal Society of Chemistry 2017 Physical chemistry chemical physics Vol.19 No.7

<P>Although the replica exchange methods (REMs) were developed as efficient conformational sampling methods for bio-molecular simulations, their application to very large bio-systems is somewhat limited. We propose a new replica exchange scheme (Tq-REM) created by combining the conventional temperature-REM (T-REM) and one of the Hamiltonian-REMs, q-REM, using the effective potential with reduced barriers. In the proposed Tq-REM scheme, high temperature replicas in T-REM are substituted with q-replicas. This combined scheme is expected to exploit advantages of the T-REM and q-REM resulting in improved sampling efficiency while minimizing the drawbacks of both approaches. We investigated the performance of Tq-REM compared with T-REM by performing all-atom MD simulations on Met-enkephalin, (AAQAA) 3, and Trpzip2. It was found that convergence of the free energy surfaces was improved by Tq-REM over the conventional T-REM. In particular, the trajectories of Tq-REM were able to sample the relevant conformations for all of the metastable folding intermediates, while some of the local minimum structures are poorly represented by T-REM. The results of the present study suggest that Tq-REM can provide useful tools to investigate systems where metastable states play important roles.</P>

Two-phase flow friction at high void fraction in porous media with small particles and its impact on dryout heat flux evaluation

Lee, M.,Park, H.S.,Park, J.H.,Moriyama, K.,Kim, M.H. Elsevier 2019 International journal of multiphase flow Vol.118 No.-

<P><B>Abstract</B></P> <P>The effect of interfacial friction at a high void fraction on the estimation of the dryout heat flux (DHF) of particle beds under co-current two-phase flow conditions is investigated. The objective is to reduce uncertainties in the assessment of debris bed coolability during a severe accident in a light water reactor (LWR).</P> <P>A review of porous media air/water pressure drop experiments and friction models in the literature revealed that the existing models cannot adequately predict the interfacial friction at high void fraction. In this study, interfacial friction at high void fraction is suggested and corresponding modifications to the flow pattern map and other friction terms are presented. The proposed model shows an acceptable agreement with the experimental data of both the air/water two-phase pressure drop and DHF experimental results within the particle size range of 2–4 mm, similar to the average diameter of debris particles (2.5–3.5 mm, Hong and An, 2018) obtained from fuel coolant interaction tests.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Improvement of two-phase friction model for high void fraction range in porous media. </LI> <LI> Modified flow pattern map for channel and annular flow in porous media. </LI> <LI> Model validation with air-water two-phase pressure drop and dryout experimental data in porous media. </LI> </UL> </P>

Support Vector Machine for String Vectors

Lee, M.,Jo, T. Springer 2006 Lecture Notes in Control and Information Sciences Vol.344 No.-

Identifying new business opportunities from competitor intelligence: An integrated use of patent and trademark databases

Lee, M.,Lee, S. Elsevier 2017 Technological forecasting social change Vol.119 No.-

This study aims to analyze the position of technology-centered companies in complex market dynamics and discover new business opportunities from competitor intelligence. For this, we consider both technology and market characteristics in providing competitor intelligence by utilizing patent data as a representative proxy for a firm's technology, and trademark data as an information source for the firm's target goods and services. To analyze the two types of data, a collaborative filtering approach together with portfolio analyses and association mining techniques were adopted. Theoretically, this is one of the earliest attempts to combine patent data and trademark data to investigate corporate strategies. In practice, the research results are expected to be used as a decision criterion to diagnose the economic value that companies can obtain by entering the market, as well as the technological value to be passed onto their customers. Thus, the proposed approach can be useful to support effective technology and business strategies in a firm.

Selective solid-phase extraction of catecholamines by the chemically modified polymeric adsorbents with crown ether

Lee, M.,Oh, S.Y.,Pathak, T.S.,Paeng, I.R.,Cho, B.Y.,Paeng, K.J. Elsevier 2007 Journal of chromatography Vol.1160 No.1-2

A simple and selective one-step solid-phase extraction procedure using chemically modified polymer resin (Amberlite XAD-4) with crown ether was investigated for the measurement of urinary catecholamines. After loading the urine samples (adjusted to pH 4) on the synthesized adsorbent cartridge, the column was washed with methanol followed by water and then the adsorbed catecholamines were eluted by 1.0mL of 6.0M acetic acid. The effectiveness of sample clean-up method was demonstrated by reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection. Under optimal condition, the recoveries of epinephrine, norepinephrine, and dopamine from spiked urine sample were >86% for all catecholamines. The detection limits (n=5) for epinephrine, norepinephrine, and dopamine were 37, 52, and 46nmol/L, respectively.

Insight from early coral-stromatoporoid intergrowth, Late Ordovician of China

Lee, M.,Elias, R.J.,Choh, S.J.,Lee, D.J. Elsevier 2016 Palaeogeography, palaeoclimatology, palaeoecology Vol.463 No.-

One of the earliest endosymbiotic associations with stromatoporoids occurs in the Late Ordovician Xiazhen Formation of southeastern China. Bajgolia, an auloporid tabulate coral characterized by dichotomous branching due to longitudinal fission, is represented by free-living as well as endobiontic forms in various lithofacies representing a wide range of environments. Only two of 11 stromatoporoid genera (Clathrodictyon and Ecclimadictyon) hosted Bajgolia, mainly in reef and related facies. Bajgolia-stromatoporoid associations occur occasionally in the lower part of the formation, but eventually become persistent in the upper part. Such associations were initiated by larval settlement of the coral on the growth surface of the stromatoporoid. Growth of Bajgolia usually kept pace with its host, but the coral's ability to change growth direction and grow faster prevented its envelopment and termination by the stromatoporoid, allowing the establishment and recurrence of an ongoing endosymbiotic relationship between the two organisms. Endobiontic Bajgolia was able to survive with its corallites protruding from the host; in some cases, the growth form of the stromatoporoid changed in response to the coral. The relationships between Bajgolia and stromatoporoids were probably commensal, but there is also evidence for mutualism and/or parasitism. Bajgolia-stromatoporoid associations represent an important stage in the development of complex ecological relationships and community structure, prior to the common and widespread syringoporid (''caunopore tubes'')-stromatoporoid associations in the Siluro-Devonian.

Anatase TiO₂ nanosheets with surface acid sites for Friedel-Crafts alkylation

Lee, M.,Seo, Y.,Shin, H.S.,Jo, C.,Ryoo, R. Elsevier 2016 Microporous and mesoporous materials Vol.222 No.-

<P>The solvothermal synthesis route to mesoporous TiO2 using a vinylphenol polymer structure-directing agent (SDA) was optimized to provide a high yield of bilayer nanosheets. The resultant TiO2 material exhibited a high BET area of 420 m(2) g(-1) after the removal of SDA. Structural analysis of the nanosheets was carried out using powder X-ray diffraction, high resolution-transmission electron microscopy, Raman spectroscopy and solid-state NMR. The results indicated that the TiO2 material consisted mainly of the bilayer nanosheets with (010) facet-dominant anatase crystal structure. The thickness of the nanosheet was 0.75 nm, corresponding to two unit-cell parameters along the b-axis in the anatase crystal system. More than 10% of the surface Ti atoms were terminated with bridging O-H groups and coordinatively unsaturated Ti atoms, which acted as Bronsted and Lewis acid sites. Accordingly, the anatase nanosheets exhibited catalytic performance in the liquid-phase Friedel Crafts alkylation of aromatic compounds. (C) 2015 Elsevier Inc. All rights reserved.</P>