Living with multiple sclerosis: A family's narrative

Yongchul Chung 한국운동재활학회 2013 한국운동재활학회 학술대회 Vol.2013 No.1

Computational Screening of Nanoporous Materials for Hexane and Heptane Isomer Separation

Chung, Yongchul G.,Bai, Peng,Haranczyk, Maciej,Leperi, Karson T.,Li, Peng,Zhang, Hongda,Wang, Timothy C.,Duerinck, Tim,You, Fengqi,Hupp, Joseph T.,Farha, Omar K.,Siepmann, J. Ilja,Snurr, Randall Q. American Chemical Society 2017 Chemistry of materials Vol.29 No.15

<P>Computational high-throughput screening was carried out to assess a large number of-experimentally reported metal-organic frameworks (MOFs) and zeolites for their utility in hexane isomer separation. Through the work, we identified many MOFs and zeolites with high selectivity (SL+M > 10) for the group of n-hexane, 2-methylpentane, and 3-methylpentane (linear and monobranched isomers) versus 2,2-dimethylbutane and 2,3-dimethylbutane (dibranched isomers). This group of selective sorbents includes VICDOC (Fe-2(BDP)(3)), a MOF with triangular pores that is known to exhibit high isomer selectivity and capacity. For three of these structures, the adsorption isotherms for a 10-component mixture of hexane and heptane isomers were calculated. Subsequent simulations of column breakthrough curves showed that the DEYVUA MOF exhibits a longer process cycle time than VICDOC MOF or MRE zeolite, which are previously reported, high-performing materials, illustrating the importance of capacity in designing MOFs for practical applications. Among the identified candidates, we synthesized and characterized a MOF in a new copper form with high predicted adsorbent capacity (q(L+M) > 1.2 mol/L) and moderately high selectivity (SL+M approximate to 10). Finally, we examined the role of pore shape in hexane isomer separations, especially of triangular-shaped pores. We show through the potential energy surface and three-dimensional siting analyses that linear alkanes do not populate the corners of narrow triangular channels and that structures with nontriangular pores can efficiently separate hexane isomers. Detailed thermodynamic analysis illustrates how differences in the free energy of adsorption contribute to shape selective separation in nanoporous materials.</P>

Developing youth through sport: Strategies used by ten coaches

( Yongchul Chung ) 한국스포츠정책과학원(구 한국스포츠개발원) 2017 International Journal of Applied Sports Sciences Vol.29 No.1

The purpose of this study was to identify effective strategies for life skill development utilized by coaches. Ten (10) veteran football coaches were recruited and interviewed. Each interview lasted approximately for two hours. All recorded data were transcribed verbatim and later used for further analyses. The results were presented in 13 parts organized by key interview foci: the role of academic coach; the typical day of academic coach; key components for program success; the goals of the academic coach; success stories; effective strategies; ineffective strategies; strengths of academic coaches; weaknesses of academic coaches; strengths of the program; limits of the program; gender/ethnic issues; and recommendations for future academic coaches. Positive youth development strategies were categorized into two hierarchical levels. One is global macro level strategies and the other is specific micro level ones. Based on the interviews, a number of youth development strategies, both in macro and micro level, perceived to be effective were identified. However, it should be noted that while the coaches perceived these strategies were effective, they were not viewed as a panacea for all athletes in all situations. Finally, based on findings from the current study, a model for effective life skills development strategies was proposed

MOF 기반 이산화탄소 흡착 분리 소재 및 공정 기술

정용철(Yongchul Chung) 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.2

군에서의 드론편대 활용 방안에 대한 연구

김청민(Kim Chung Min),김용철(Kim Yongchul) 한국통신학회 2016 한국통신학회 학술대회논문집 Vol.2016 No.11

Limitation of model‐based estimations of the hydrogen adsorption capacities in nanoporous materials: A molecular simulation study

Yoon Sunghyun,Chung Yongchul G. 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.11

There has been a recent report regarding the existence of solid-like H2 adsorption in nanoporous materials. Herein, we employed grand canonical Monte Carlo (GCMC) simulations on a series of metal–organic frameworks with 1D and 3D channels to investigate the limitation of a model-based approach in estimating the H2 adsorption capacities. The excess hydrogen uptakes of several structures with pore sizes ranging from 5 to 37 Å were computationally predicted. The pore volume and the density of adsorbed H2 were obtained by fitting the Toth equa- tion to the excess H2 isotherm data from the simulation. The results were compared with the data obtained from direct simulation. Sensitivity analyses show that the pore volume and the density of adsorbed H2, predicted from modelbased fitting, are not accurate enough to estimate the adsorbed H2 density and the pore volume, especially for the materials with 1D channels

접촉스포츠 운동선수들의 분노경험에 대한 이해

이상미 ( Sangmi Lee ),정용철 ( Yongchul Chung ) 한국체육학회 2020 한국체육학회지 Vol.59 No.1

본 연구는 접촉스포츠 운동선수들의 분노발생 과정을 확인하고, 분노를 처리하는 과정과 그에 따른 결과 대해 구조적 관계를 살펴보는데 목적이 있다. 연구 참여자는 총 12명(은퇴선수: 6명, 현역선수: 6명)을 선정하여 심층면접을 실시하였고 이를 토대로 자료를 수집하여, 근거이론방법(Strauss & Corbin, 1998)을 통해 분석하였다. 연구결과에 따르면 첫째, 개방코딩 결과 운동선수들의 분노과정에 대한 관한 58개의 개념, 14개의 하위범주, 그리고 10개의 상위범주가 도출되었다. 둘째, 축 코딩 결과 지도력불만, 편파판정, 상대선수행동, 운동수행저하, 상황적 특성, 끓어오름, 심리적 전략, 주요타자의 행동, 심리적 강화, 의욕감퇴 등의 범주들이 구조적인 관계를 나타냈다. 셋째, 선택코딩 결과 본 연구의 핵심범주는 분노경험으로 도출되었다. 운동선수들의 훈련 및 시합상황에서 개인적, 외부적 요인들에 의해 발생된 분노경험은 동기유발, 의욕저하 같은 심리적 전략을 사용하는 방식에 따라 심리적 강화, 의욕감퇴 등과 같은 상이한 결과를 보였다. 마지막으로 본 연구결과의 제한점 및 후속연구를 위한 제언에 대해 논하였다. The purpose of the present research is to explore the process of athletes’experiences of anger. In-depth interviews were conducted with a total number of 12 selected participants (Retired athletes: 6, Active athletes: 6), and the data were collected on the basis of the above interviews and analyzed through Grounded Theory(Strauss & Corbin, 1998). According to the results of the research: First, 58 concepts, 14 sub-categories, and 10 parent categories were derived in the process of athletes’anger. Second, categories such as dissatisfaction with leadership, biased judgment, opponents’ behavior, reduced athletic performance, situational factor, boiling, psychological strategy, major hitters’ behavior, psychological reinforcement, and disincentive indicated a structural relationship. Third, the experience of anger was derived as the core category of this study. Finally, the limitations of the results in this study and proposals for follow-up researches were discussed.

Two dimensional Zn-stilbenedicarboxylic acid (SDC) metal-organic frameworks for cyclic carbonate synthesis from CO2 and epoxides

최각규,Jintu Francis Kurisingal,CHUNG YONGCHUL GREGO,박대원 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.6

A two-dimensional Zn-based metal-organic framework has been synthesized by using Zn(II) ions and H2SDC (4,4'-stilbenedicarboxylic acid) under solvothermal conditions. The framework having a trinuclear Zn3-(RCO2)6 SBUs connected by the 4,4'-stilbenedicarboxylic acid to form a hexagonal network, shows a two-dimensional structure and displays high thermal stability up to approximately 330 oC. The role of Zn2+ (from Zn-SDC) for epoxide activation and Br- ion (from TBABr) for ring opening of epoxide was studied for the cycloaddition reaction of CO2 and propylene oxide (PO) under ambient conditions. Zn-SDC was found catalytically efficient towards CO2-epoxide coupling under ambient reaction conditions with high selectivity towards the desired cyclic carbonates under solvent-free conditions. The effects of various reaction parameters such as catalyst loading, temperature, CO2 pressure, and time were evaluated. Zn-SDC was easily separable and reusable at least five times without any considerable loss in the initial activity. A plausible reaction mechanism for the cycloaddition reaction was also proposed based on literature and experimental inferences.

Large-Scale Refinement of Metal−Organic Framework Structures Using Density Functional Theory

Nazarian, Dalar,Camp, Jeffrey S.,Chung, Yongchul G.,Snurr, Randall Q.,Sholl, David S. American Chemical Society 2017 Chemistry of materials Vol.29 No.6

<P>Efforts to computationally characterize large numbers of nanoporous materials often rely on databases of experimentally resolved crystal structures. The accuracy of experimental crystal structures used in such calculations has a significant impact on the reliability of the results. In this work, we report structures optimized using periodic density functional theory (DFT) for more than 800 experimentally synthesized metal-organic frameworks (MOFs). Many MOFs changed significantly upon structural optimization, particularly materials that were crystallographically resolved in their solvated form. For each MOF, we simulated the adsorption of CH4 and CO2 using grand canonical Monte Carlo both before and after DFT optimization. The DFT optimization has a large impact on simulated gas adsorption in some cases. For example, CO2 loading at 1 bar changed by more than 25% in over 25% of the MOFs we considered.</P>

Elucidation of flexible metal-organic frameworks: Research progresses and recent developments

Lee, Jae Hwa,Jeoung, Sungeun,Chung, Yongchul G.,Moon, Hoi Ri Elsevier 2019 Coordination chemistry reviews Vol.389 No.-

<P><B>Abstract</B></P> <P>Flexibility is a unique property of metal-organic frameworks (MOFs) that differentiates them from other rigid inorganic porous materials such as zeolites and porous silica. Flexible frameworks are not only scientifically interesting, but also applicable for real-world gas storage/delivery, separation, sensing, and catalysis. So far, a plethora of MOFs with flexible frameworks, termed as ‘soft porous crystal’, ‘flexible MOF’, ‘breathing MOF’, ‘sponge-like MOF’ or ‘dynamic MOF’, has emerged as a new subclass of MOFs. In this review, we discuss diverse perspectives and approaches to understand and control the flexible behaviour in an archetypal MOF platform so that the basic principles can be imparted to the broad community of chemists, materials scientists, and engineers. In addition, potential applications of flexible MOFs will be briefly introduced along with advanced analytic tools and molecular modelling that aid the exploration of the flexibility of MOFs in various conditions and widen the insight to design of novel flexible MOFs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Revisiting archetypal MOFs (MOF-5, HKUST-1, UiO-66, ZIFs, MIL-53, etc.) in terms of flexibility. </LI> <LI> Understanding the various forms of flexibility for design of novel flexible MOFs. </LI> <LI> Insights broadened by the advanced analytical and computational techniques. </LI> <LI> Potential applications of flexible MOFs toward their practical uses. </LI> </UL> </P>