코로나19 확산에 따른 가족생활 및 가족관계의 변화와 스트레스

진미정 ( Meejung Chin ),성미애 ( Miai Sung ),손서희 ( Seohee Son ),유재언 ( Jaeeon Yoo ),이재림 ( Jaerim Lee ),장영은 ( Young Eun Chang ) 대한가정학회 2020 Human Ecology Research(HER) Vol.58 No.3

This study explores how the COVID-19 pandemic has changed family life and relationships as well as how these changes affect perceived stress among married men and women. This study investigated changes in family time use, household work, child care, leisure activities, income and expenditures along with relationships between spouses and children using a sample of 627 married persons surveyed online from May 19 to 25, 2020. The results showed that the amount of time spent on household work, child care, and family leisure have increased and that the perceived burden of household work and child care has also increased. Gender differences were found in time use, household work, and child care. Leisure activities have changed toward more time watching TV or online media and playing online games and less time on outdoor activities, shopping, and meeting friends. About 38% of respondents reported a reduction in household income and 22% reported an increase in household debt. The majority experienced no change in the quality of relationships with spouses and children, approximately 20% of the sample reported a positive change in relationships with spouses and children. The findings of multivariate regression indicated that change in work time, negative change in household economy, negative change in household work and negative change in relationships with spouses were associated with marital stress. However, this study found that negative changes in child care and in relationships with children did not affect stress among married parents with children in elementary or secondary school.

Chemical potential and solid-solid equilibrium of near-spherical Lennard-Jones dumbbell crystal

Jaeeon Chang,Sangwon Lee,Minkyu Kim 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3

We studied the orientational order-disorder transition of crystals made up of near-spherical Lennard-Jones dumbbells, of which reduced bond lengths are 0.225, 0.250 and 0.275. Various techniques of Monte Carlo (MC) simulations are used to calculate the chemical potentials of ordered and disordered crystals, and thereby to predict orderdisorder phase transition. First, we performed NPT MC simulations to determine crystal structure, equilibrium positions and orientations of the molecules. We then calculated the free energies of the crystals using the expanded ensemble MC simulations combined with the Einstein-molecule method and the thermodynamic integration method. The solid-solid phase equilibrium is determined from the free energy profiles of the individual phases by equating the chemical potential. The predictions of phase transition obtained from the conventional NPT MC simulation and the free energy simulation were in excellent agreement with each other, which confirms the validity of the present method of calculating the chemical potential of crystal. In addition, the Gibbs-Duhem integration was performed to obtain a complete coexistence curve between the two crystal phases. Orientational probability distributions of molecular axes were analyzed to find the characteristic behavior of rotational motion of molecule in the crystal. At sufficiently low temperature, flipping rotation of molecule in the ordered crystal is suppressed. In contrast, the flipping rotation occurs at higher temperature close to the transition while orientationally ordered structure is still maintained. In the freeenergy calculation, such a unique rotational behavior requires to use a suitable form of external rotational potential with proper symmetry number. The present study demonstrates how one can judiciously choose a correct simulation scheme for the calculation of chemical potentials of molecular crystals.

Supplementary graphical analysis for the multi-density expansion of associating fluids

Jaeeon Chang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.3

We present a detailed analysis of Wertheim’s multi-density formulation for the thermodynamic propertiesof associating fluids with a single attraction site. Graphical expressions are explicitly illustrated for the partitionfunction, multi-densities and direct correlation functions, and they are compared with those from the classical singledensityformulation of simple fluids. The steric incompatibility among three monomers greatly simplifies cluster integralsof associating fluids, which allows dimerizing association only. Graphical expressions for the pressure and the Helmholtzenergy are derived by using functional derivatives, which provide a theoretical base for TPT and SAFT equations ofstate.

MOLECULAR DYNAMIC SIMULATION AND EQUATION OF STATE OF LENNARD - JONES CHAIN FLUIDS

Chang, Jaeeon,Kim, Hwayong 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.5

SAFT 상태 방정식과 회합성 유체 혼합물의 기액 상평형

장재언 ( Jaeeon Chang ) 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.5

We review SAFT equation of state (EOS) which is based on TPT theory and statistical-mechanical principles, and confirm that it can be used as a useful tool to predict vapor-liquid phase equilibria of associating fluid mixtures. We examine theoretical structure of PC-SAFT EOS in great detail, and then assess the applicability and performance of the EOS while applying it to various mixtures containing nonpolar components, polar components and associating components in a stage-wise manner. In contrast to the conventional engineering EOS, PC-SAFT EOS can accurately predict nonideal behaviors of those mixtures without using semi-empirical binary interaction parameter. This is because the SAFT theory is based on a rigorous theoretical framework at molecular level which effectively accounts for various intermolecular interactions, and it thus provides substantial benefits in applying the SAFT EOS to complex thermodynamic phenomena of multi-component mixtures.

Multidensity Integral Equation Theory for Hard-Sphere Monomer-Chain Mixture Fluids : Analytical Expression for the Overall Correlation Function

염민선,김화용,Jaeeon Chang 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.3

We employ the multidensity integral equation theory (MOZ) to investigate the structural properties of flexible hard-sphere monomer-chain mixture fluids. The analytical solution for the overall correlation function of such mixture fluids are obtained by applying the Laplace transformation method to the MOZ theory with the PPY ideal-chain approximation. Theoretical results for the overall correlation function have been calculated and compared with the computer simulation.

Structure and Dynamics in Surfaces of Polymers and Organic Electronic Materials

Do Y. Yoon,Sanghun Lee,Youngsuk Jung,Jungho Jo,Wonhee Jeong,Jaeeon Chang,Jan Luning 한국고분자학회 2006 한국고분자학회 학술대회 연구논문 초록집 Vol.2006 No.10

가족의 코로나19 관련 정책 인지도, 이용 정도, 이용 만족도 및 요구도

성미애(Miai Sung),진미정(Meejung Chin),장영은(Youngeun Chang),유재언(Jaeeon Yoo),손서희(Seohee Son) 한국가족정책학회 2021 가족정책연구 Vol.1 No.1

본 연구는 코로나19 대응 정책의 적절성과 효과성을 평가하는 기초 연구로, 만 20~64세 성인(461명)을 대상으로 2020년 5월과 11월 두 차례에 걸쳐 정책에 대한 인지도, 이용 정도, 이용 만족도 및 요구도를 살펴보고자 STATA 14.0 프로그램을 이용하여 기술통계치와 쌍체 t 값을 구하였다. 연구를 통해 도출한 결론은 다음과 같다. 첫째, 인지도가 높은 정책은 1차 때는 긴급재난지원금, 유연근무제, 긴급돌봄지원 등이었으며, 2차 때는 유연근무제, 통신비, 긴급돌봄지원이었다. 둘째, 이용한 정책은 1차 때는 긴급재난지원금이었으며, 2차 때는 긴급재난지원금신청이 없어지면서 정책 이용 비율이 낮아졌다. 셋째, 이용 만족도가 높은 정책은 1차 때는 아동돌봄쿠폰, 긴급재난지원금 등이었으나 2차 때는 긴급돌봄지원과 아동돌봄쿠폰 등이었다. 넷째, 정책 요구도는 1, 2차 조사에서 유사하게 일자리 공급/유지, 소득지원 등에 대한 요구가 높았다. 그러나 일부 정책에서는 1, 2차 사이에 요구도가 달라졌는데, 노인돌봄, 가족상담 및 교육 요구도는 더 높아진 반면, 소득지원 및 가족여가 지원은 더 낮아졌다. 그리고 미취학자녀가 있는 가족에서 코로나19 관련 정책에 대한 요구도가 가장 높았다. 이처럼 코로나19의 장기화에 따라 시간의 변화 및 가족 특성에 맞는 정책이 필요하다. This study aims to examine Korean families’ response to COVID-19-related policies in terms of awareness and utilization. The adequacy of these policies is also assessed by examining satisfaction towards and demand for them. An analysis of data collected from 461 people surveyed in May and November of 2020 showed that respondents were aware of COVID-19-related policy measures in the following order: 1) emergency disaster relief fund, followed by 2) a flexible work system and 3) the urgent childcare support measure. The most utilized policy measure was the emergency disaster relief fund. Satisfaction was high in May towards the temporary cash assistance measure, and in November towards the care services measure. The policy demand for elderly care and family counseling and education increased between May and November, while the policy demand for cash assistance and family leisure support decreased. In particular, the policy demand from families with preschool children was higher than that from families with school-age children. This study suggests that COVID-19-related policy measures should accommodate the different and evolving needs of different households based on family characteristics as the pandemic progresses.

CO2 absorption, density, viscosity and vapor pressure of aqueous potassium carbonate+2-methylpiperazine

Soung Hee Yun,Young Eun Kim,Jeong Ho Choi,Sung-Chan Nam,Jaeeon Chang,윤여일 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12

The physical properties of the absorbent are important for designing a CO2 capture process. The density and viscosity are used to calculate the mass transfer coefficient that determines the height of the absorber. Furthermore, these physical data affect the selection of liquid pump and pipe lines. Vapor pressure is a factor that estimates absorbent loss and condenser size. In this study, the physical properties of the aqueous potassium carbonate (K2CO3)+2-methylpiperazine (2MPZ) solution were obtained in a temperature range from 303.15 K to 343.15 K. The physical properties of the different aqueous K2CO3+2MPZ solutions (various amine concentrations and amounts of CO2 absorbed) were measured to obtain the parameters for process design. A regression analysis was conducted for the experimental data. The densities of the aqueous K2CO3+2MPZ solutions increased when the amounts of absorbed CO2 or 2MPZ concentrations were increased. The densities and viscosities of the absorbents decreased according to the increase in temperature. The viscosities of the absorbent increased when 2MPZ concentrations were increased. The temperature dependency of vapor pressure follows the Antoine equation; the CO2 gas and aqueous solution of a base follows the vapor pressure variation of the mixed solution.