Wetting Transition Characteristics on Microstructured Hydrophobic Surfaces

Lee, Jae Bong,Gwon, Hyuk Rok,Lee, Seong Hyuk,Cho, Minhaeng The Japan Institute of Metals 2010 MATERIALS TRANSACTIONS Vol.51 No.9

<P>Hydrophobicity and wetting transition behavior of water droplets were investigated on microstructured hydrophobic rough surfaces with pillar arrays, fabricated by self-replication with hydrophobic polydimethylsiloxane(PDMS) together with the use of CNC machine. The surfaces consist of microscale pillars(diameter: 105 μm, height: 150 μm) with varying spacing-to-diameter ratio (<I>s</I>⁄<I>d</I>) ranging from ∼1.0 to ∼3.3. A de-ionized(DI) water droplet of 4.3 μl was placed on hydrophobic surfaces and contact angles(CA) were measured by the digital image processing algorithm. A wetting transition from the Cassie state to the Wenzel state was demonstrated depending on the values of <I>s</I>⁄<I>d</I>, from ∼1.81 to ∼2.95. In the transition regime, a partial penetration of liquid meniscus which moves downward in the groove formed by four pillar posts was observed. It was also found that the contact angle prediction using the Cassie-Baxter equation showed fairly good agreement with experimental data, whereas in the transition regime, the rapid decrease in CA was found.</P>

Temporal Structure on Discourse bevel within the Controlled Information Packaging Theory

( Minhaeng Lee ),( Ik-hwan Lee ) 한국언어정보학회 2002 언어와 정보 Vol.6 No.1

The temporal structure of events on the discourse level has long been of great interest in both theoretical and computational linguistics. In this paper, we offer a unified approach to the temporal relationships related to a hierarchical discourse structure. We apply the method of pronoun resolution to the interpretation of tense. It is based on an analysis within the framework of the controlled information packaging theory. A unique aspect of our account is that temporal interpretation across discourse segments in global discourse is subject to the same principles as the interpretation of global anaphora, and that there is thus no need to postulate independent principles to account for the discourse behaviour of tense. In this way, we can neatly explain the general view that tense parallels the anaphoric nature of pronouns. (Yonsei University)

Amide I IR probing of core and shell hydrogen-bond structures in reverse micelles

Lee, Jooyong,Jeon, Jonggu,Kim, Min-Seok,Lee, Hochan,Cho, Minhaeng International Union of Pure and Applied Chemistry 2014 Pure and Applied Chemistry Vol. No.

<P><B>Abstract</B></P><P>The properties of<I>N</I>-methylacetamide (NMA) molecules encapsulated in the reverse micelles (RMs) formed by anionic surfactant aerosol OT (AOT), are studied with vibrational spectroscopy and computation. Vibrational spectra of the amide I′ mode of the fully deuterated NMA-<I>d</I><SUB>7</SUB>show gradual increase of peak frequencies and line broadening as the size of RMs decreases. Analyses of the spectral features reveal the presence of three states of NMA-<I>d</I><SUB>7</SUB>that correspond to NMA located in the core of water phase (absorption frequency of 1606 cm<SUP>-1</SUP>) and two types of interfacial NMA near the surfactant layer (1620 and 1644 cm<SUP>-1</SUP>). In larger RMs with water content<I>w</I><SUB>0</SUB>= [D<SUB>2</SUB>O]/[AOT] ≥ 10, only the first two states are observed, whereas in smaller RMs, the population of the third state grows up to 25 % at<I>w</I><SUB>0</SUB>= 2. These results indicate the general validity of the two-state core/shell model for the confined aqueous solution of NMA, with small modifications due to the system-dependent solute-interface interaction. However, simulations of small RM systems with<I>w</I><SUB>0</SUB>≤ 15 show continuous variations of the population, frequency shifts, and the solute-solvent interaction strengths at solute-interface distance less than 4 Å. Thus, the distinction of solute core/shell states tends to be blurred in small RMs but is still effective in interpreting the average spectroscopic observables.</P>

Conflgurationality Parameter in Korean and its Computational Lmplication-An HPSG Approach

( Minhaeng Lee ) 한국언어정보학회 1992 국제 워크샵 Vol.1992 No.-

Vibrational Spectroscopic Determination of Local Solvent Electric Field, Solute–Solvent Electrostatic Interaction Energy, and Their Fluctuation Amplitudes

Lee, Hochan,Lee, Gayeon,Jeon, Jonggu,Cho, Minhaeng American Chemical Society 2012 The journal of physical chemistry. A, Molecules, s Vol.116 No.1

<P>IR probes have been extensively used to monitor local electrostatic and solvation dynamics. Particularly, their vibrational frequencies are highly sensitive to local solvent electric field around an IR probe. Here, we show that the experimentally measured vibrational frequency shifts can be inversely used to determine local electric potential distribution and solute–solvent electrostatic interaction energy. In addition, the upper limits of their fluctuation amplitudes are estimated by using the vibrational bandwidths. Applying this method to fully deuterated <I>N</I>-methylacetamide (NMA) in D<SUB>2</SUB>O and examining the solvatochromic effects on the amide I′ and II′ mode frequencies, we found that the solvent electric potential difference between O(?C) and D(−N) atoms of the peptide bond is about 5.4 V, and thus, the approximate solvent electric field produced by surrounding water molecules on the NMA is 172 MV/cm on average if the molecular geometry is taken into account. The solute–solvent electrostatic interaction energy is estimated to be −137 kJ/mol, by considering electric dipole–electric field interaction. Furthermore, their root-mean-square fluctuation amplitudes are as large as 1.6 V, 52 MV/cm, and 41 kJ/mol, respectively. We found that the water electric potential on a peptide bond is spatially nonhomogeneous and that the fluctuation in the electrostatic peptide–water interaction energy is about 10 times larger than the thermal energy at room temperature. This indicates that the peptide–solvent interactions are indeed important for the activation of chemical reactions in aqueous solution.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcafh/2012/jpcafh.2012.116.issue-1/jp209709e/production/images/medium/jp-2011-09709e_0009.gif'></P>

Dipeptide Structure Determination by Vibrational Circular Dichroism Combined with Quantum Chemistry Calculations

Lee, Kyung-Koo,Oh, Kwang-Im,Lee, Hochan,Joo, Cheonik,Han, Hogyu,Cho, Minhaeng WILEY-VCH Verlag 2007 CHEMPHYSCHEM -WEINHEIM- Vol.8 No.15

<P>The solution structure and the local solvation environments of alanine dipeptide (AD, 1 a) and its isotopomer (AD*, 1 b, <SUP>13</SUP>C on the acetyl end C&n.dbond;O) are studied by using infrared (IR) spectroscopy and vibrational circular dichroism (VCD). From the amide I IR spectra of AD* in various protic solvents, it is found that each of the two carbonyl groups is fully H-bonded to two water molecules. However, the number of alcohol molecules H-bonded to each C&n.dbond;O varies from one to two, and the local solvation environments are asymmetric around the two peptides of AD* in alcohol solutions. The amide I VCD spectra of AD and AD* in D<SUB>2</SUB>O are also measured, and a series of density functional theory (DFT, B3LYP/6-311++G**) calculations are performed to obtain the amide I normal-mode rotational strengths of AD and the intrinsic rotational strengths of its two peptide fragments. By combining the VCD-measurement and DFT-calculation results and employing a coupled oscillator theory, we show that the aqueous-solution structure of the dipeptide can be determined. We believe that the present method will be of use in building up a library of dipeptide solution structures in water.</P> <B>Graphic Abstract</B> <P>Protein vibrations: Combined experimental studies and theoretical calculations determine the solution structure and the local solvation environments of alanine dipeptide (AD, see P<SUB>II</SUB> conformation in the figure) and its isotopomer (AD*). <img src='wiley_img/14394235-2007-8-15-CPHC200700352-content.gif' alt='wiley_img/14394235-2007-8-15-CPHC200700352-content'> </P>

Fokusprojektion im Deutschen und Koreanischen

Lee, Minhaeng 한국독어독문학회 2003 獨逸文學 Vol.86 No.-

본 연구는 독일어와 한국어의 초점투사 현상을 대조언어학적인 시각에서 논의한다. 일반적으로 강세언어로 알려져 있는 독일어나 영어를 중심으로 논의가 진행되어 왔던 초점투사 현상이 강세가 변별적인 기능을 갖지 못하는 한국어에서도 관찰가능한 지를 확인하는 것이 본 연구의 주된 동기였는데, 연구의 결과 한국어에서도 초점투사가 규칙성을 보이는 것으로 확인되었다. 먼저, 독일어의 초점투사 현상을 비교적 잘 설명하는 것으로 평가될 뿐만 아니라, 외국어로서의 독일어 교육에도 응용가치가 높은 Uhmann (1988, 1991)의 논항구조에 기반한 초점투사 이론을 비판적으로 검토한다. 이어서 독일어와 한국의 초점투사 현상을 적절히 기술하기 위해서는 술어논항 구조를 세 가지 유형, 곧 술어/논항-구조, 수식어/중심어-구조 그리고 주어/술어-구조로 확대하여 이해할 필요가 있음을 주장하고, 독일어의 초점투사와 관련한 보다 포괄적인 언어자료를 설명할 수 있는 방향으로 새로운 이론을 제안한다. 그런 다음, Uhmann의 화자중심의 초점토사 이론을 분석의 틀로 삼아 한국어의 여러 유형의 논항구조에 나타난 초점투사 현상을 독일어의 대응구조와 비교한다. 한국어 초점투사의 논의는 118개의 질의-응답 쌍으로 구성된 초점코퍼스의 음성분석결과에 기초하고 있다. 음성분석의 경우, 표준한국어를 구사하는 남녀 아나운서에게 읽게 한 후 녹음을 한 디지털 음성자료를 음성분석프로그램 Praat를 이용하여 강세분석을 시도했다. 초점투사 현상과 관련하여 독일어와 한국어는 공통점과 차이점을 보이는데, 술어/논항-구조가 관여된 구문의 경우 두 언어 모두 논항에 강세가 주어지며, 능격술어가 나타나는 주어/술어-구조가 관여된 구문의 경우 두 언어 모두 주어에 강세가 주어진다는 공통점을 가진다. 반면, 수식어/중심어-구조의 경우 독일어에서는 후행하는 요소에 강세가 주어지지만 한국어에서는 중심어에 강세가 주어진다는 차이점을 보인다. 두 언어간의 다른 차이점들을 들자면 다음과 같다: 첫째, 개체층위의 술어가 나타나는 주어/술어-구조가 관여된 구문의 경우 독일어에서는 술어에 강세가 주어지나 한국어의 경우 주어에 강세가 부여된다. 둘째, 무대층위의 술어가 나타나는 주어/술어-구조가 관여된 구문의 경우 독일어와 한국어 모두 주어에 강세가 주어진다. 이 연구에서는 논의의 대상을 중립초점 구문으로 한정했으나, auch/도 nur/만 sogar/조차 등 초점불변화사가 나타나는 구문으로 논의를 확대하면 초점투사에 관한 보다 일반화된 연구결과를 얻을 수 있을 것으로 기대된다.

독-한 명사구 기계번역시스템의 구축

이민행 ( Lee Minhaeng ),최승권 ( Sung-kwon Choi ),최경은 ( Kyung-eun Choi ) 한국언어정보학회 1998 언어와 정보 Vol.2 No.1

This paper aims to describe a German-Korean machine translation system for nominal phrases. Besides, we have two subgoals. First, we are going to reveal linguistic differences between two languages and propose a language-informational method to overcome the differences. The method is based on an integrated model of translation knowledge, efficient information structure, and concordance selection. Then, we will show the statistical results about translation experiment and its evaluation as an evidence for the adequacy of our linguistic method and translation system itself. (Yonsei University, SERI, Yonsei University)

한국어에서의 정보포장: 대명사 해결을 중심으로

이민행 ( Minhaeng Lee ) 한국언어정보학회 2000 언어와 정보 Vol.4 No.1

이 논문에서는 국지적인 대명사의 해결을 위한 이론적인 틀로 널리 아려진 중심화이론의 여러 이론적인 정보포장이론이라는 새로운 담화의미론으로 발전시킬 수 있음을 보이고자 한다. 이로써 한국어 담화상에 나타나는 대명사의 선행사 탐색이 상당히 설득력있게 이루어질 수 있음을 보였다. 이를 위해 먼저 제한된 영역대화라 할 수 있는 호텔예약대화에 나타나는 영대명사의 특징에 대해 논의한다. 이어서, 대명사 해결과 관련하여 정보구조가 중심화이론의 주요 구성요소인 정향적 중심리스트 서열 구성에 직접 반영되어야 함을 보인다. 마지막으로 대명사를 담화통어할 수 있는 위치에 있어야 한다는 담화통어제약을 제안하여 광역대화에 나타나는 명시적인 대명사의 해결을 위한 하나의 대안을 제시한다.

마이크로 공동의 고분자 마찰 및 마모에 대한 영향 연구

조민행(Minhaeng Cho),이재봉(Jaebong Lee),이성혁(Seonghyuk Lee),박상일(Sangil Park) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

Micro-cavities manufactured by laser surface texturing technique were studied in terms of their effect on friction and wear of polyoxymethylene (POM). As a preliminary study, a number of attempts to reduce refilling phenomenon of a cavity by melting and flow of POM were made in this study. As a result, it revealed that a strong jet of air applied during laser irradiation is significantly effective in removing the refilling behavior. Cavities with a number of different concentrations, which are the ratio of the total cavity opening area to the total specimen surface area, were then fabricated and tested in ball-on-disk sliding configuration in dry contact. Surfaces after each test were examined by SEM to investigate the correlation between the cavity concentration and tribological behavior of POM. Also, correlation between wear and friction of POM and failure of cavities caused during sliding contact is provided in this study.