Two-dimensional interfacial assembly of graphene platelets

심종원,김상욱 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

Study of colloidal self-assembly is much strong simulation tool for understaning genral chemistry phenomena and it is also very helpful to develop the concept of tiny chemical factories, which are manufactured simultaneously. Although it is ture that solution-based techniques are considered as scalable and economical mass production of graphene, lack of understanding about graphene platelet properties as a colloid and reliable production method for producing graphene as abuilding units make lower the progression of colloidal graphene applications. Practically, to understand colloidal movement or other characters of graphene paltelets, reliable suppliment of graphene building units is the first consideration. After an intensive and extensive search for appropriate solvents, highly concentrated colloidal suspensions of almost single-layered graphene sheets have been obtained by chemically exfoliated graphene oxide but it still needs additional costly reduction process for deteriorated original properties. On the other hand, high quality graphene also acquired by sonication of graphite in organic solvents such as NMP (N-methylpyrrolidone) for a very long time. However, the concentration of the suspension and yield of single layers were quite low and work in improving issues is still needed. Therefore, in this study, we suggested much improved, efficient way for mass production of high quality graphene. This sophisticated electrochemical exfoliation method can procure of consistent quality of graphene platelets generation. Using these building units, solution processing of pristine graphene based films was fabricated. Typically, graphene condicting film has great potential for the development of transparent electrodes, surface coatings, composites, sensors and separation membranes. However, the low solution compatibility of pristine graphene precludes the use of conventional processing methods such as dropcasting, spin-coating, and rod-coating. Here we report a rapid robust method for assembling pristine graphene platelets into a large area uniform film at a liquid-air interface. The platelets are assembled at the surface of a dilute suspension using an evaporation-driven Rayleigh- Taylor instability and then are driven together by Marangoni forces. The platelets are fixed through physical binding of their edges. Typically, 8-cm-diameter circular graphene films are generated within two minutes. Once formed, the films can be transferred onto various substrates with flat or textured topologies. This interfacial assembly protocol is applicable to other nanomaterials, including 0D fullerene and 1D carbon nanotubes, which commonly suffer from limited solution compatibility.

제2회 대주 기술상 수상

심종원 한국공업화학회 2004 공업화학전망 Vol.7 No.6

지역주택시장의 특징과 임대차시장의 구조적 변화

심종원 한국주택학회 2014 한국주택학회 학술대회 발표논문집 Vol.- No.1

Synthesis and characterization of poly (e-caprolactone)/poly (ethyleneglycol) block copolymers for biodegradable self-assembled nanoparticles

심종원,강형석,한상훈,장이섭 한국공업화학회 2002 한국공업화학회 연구논문 초록집 Vol.2002 No.1

Enhanced Properties of Modified Gelatin Based Matrice for Artificial Skin

심종원,이승준,이영무 한국고분자학회 1999 한국고분자학회 학술대회 연구논문 초록집 Vol.24 No.2

A case of autoimmune pancreatitis suspected as pancreatic cancer

심종원,이규택 대한내과학회 2019 대한내과학회 추계학술대회 Vol.2019 No.1

주택담보대출 연체율 결정 요인에 관한 연구

심종원 ( Jong Won Shim ),정의철 ( Eui Chul Chung ),정현정 ( Hyun Jung Jung ) 韓國不動産分析學會 2009 不動産學硏究 Vol.15 No.2

This paper examines the determinants of housing mortgage delinquency rate. Based on household utility maximization framework, we derived two competing hypotheses on mortgage delinquency: equity hypothesis and ability-to-pay hypothesis. Using monthly time series data on unemployment rate, consumer price index, mortgage interest rate, and house price index, a VAR was performed to identify interrelationships among the variables, and impulse response and variance decomposition were analyzed to find out the impacts of the relevant variables. It was found that changes in unemployment rate and consumer price index were the main determinants of the housing mortgage delinquency rate, which supports the ability-to-pay hypothesis. A change in house price index explained little of the change in mortgage delinquency rate. Impulse response analyses showed that unemployment rate and consumer price index positively affected the movement of the delinquency rate and the house price index had a negative influence on the delinquency rate. Variance decomposition analyses revealed that the relative effect of the consumer price index on the delinquency rate was the largest, followed by the unemployment rate. Mortgage interest rate was not effective to explain the movement of the delinquency rate.

우리나라 가구의 주택 전,월세 선택 결정요인 분석

심종원 ( Jong Won Shim ),정의철 ( Eui Chul Chung ) 한국부동산분석학회 2010 不動産學硏究 Vol.16 No.3

This study attempts to examine how households choose between the two types of rental contracts, Chonsei and Monthly Rent with Variable Deposit (MRVD), and whether there exist any difference in the way of deciding a rental contract type. Probit models are estimated after theoretically analyzing the structure for selecting optimal rental housing contract type. Contrary to existing literature, we carefully derived the relative cost of rental housing and incorporated the variable in our estimation. The estimation results show that net asset and permanent income are important determinants on the choice of Chonsei over MRVD contract. The relative cost of rental housing is found to significantly affect the choice of rental contract type. The larger the amount of net asset and the larger the permanent income, and the smaller the rental cost of Chonsei over the rental cost of MRVD, it is more likely that households choose Chonsei over MRVD. Overall, our analysis indicates that net asset, permanent income and relative cost of rental housing are important factors in deciding a rental contract type.

시계열분석기법을 활용한 아파트 전세와 보증부월세 계약비율 변화요인 분석

심종원(Jong-Won Shim),정의철(Eui-Chul Chung) 한국주택학회 2010 주택연구 Vol.18 No.4

통계청 인구센서스 자료에 따르면 1995년 임차가구 중 전세가구의 비중은 63.57%이며 보증부월세가구의 비중은 22.04%이나, 2000년에는 임차가구 중 전세가구 비중은 61.59%, 보증부월세의 비중은 23.24%로 보증부월세의 비중이 약간 증가하였다. 그리고 2005년에는 임차가구 중 전세가구의 비중은 50.39%, 보증부월세의 비중은 33.92%로 외환위기 이후 전세제도가 주를 이루던 임대주택시장에서 보증부월세 계약의 비중이 늘어나고 있다. 이러한 임대계약형태의 변화는 전세에 의지하던 기존의 국내 주택 임대차시장의 해석에서 보증부월세에 대한 관심을 높이는 계기가 되었다. 그런데 우리나라 주택 임대차시장의 대표적인 형태인 전세와 보증부월세 계약추이를 설명하기 위해서는 보다 폭넓은 논의가 필요하다. 이에 본 연구에서는 첫째, 임대인 입장에서 전세와 보증부월세의 계약 추이를 시계열분석을 통하여 분석하였다. 이론적 모형에서는 전세와 보증부월세의 계약구조는 자산보유자인 임대인이 자기자본에 대한 투자수익률을 극대화하는 과정에서 이루어지며 이 과정에서 재무레버리지의 효과가 중요한 요인이 될 수 있음을 제시하였다. 또한 전윌세 전환율뿐만 아니라 매매가격 상승 예상률, 주택담보대출 금리, 매매가격 대비 전세 보증금의 비율, 매매가격 대비 보증부월세 보증금의 비율도 전세와 보증부월세의 계약 구조에 영향을 주는 중요한 요인임을 밝혔다. 실증분석에서는 전세와 보증부월세의 자기자본에 대한 투자수익률에 대한 시장관찰지표인 보증부월세 계약 대비 전세 계약의 비율에 영향을 미치는 관련 변수들의 효과를 오차수정모형을 이용하여 추정하였다. 추정결과, 보증부월세 계약비율 대비 전세 계약비율에 매매가격 상승 예상률은 양(+)의 효과를, 전월세 전환율은 음(-)의 효과를 보이는 것으로 나타났다. Recently, the rental housing market in Korea has experienced substantial changes in preferred rental contracts between Chonsei and monthly-rent-with-variable-deposit. Until a few years ago, Chonsei has been a dominant rental contract. However, for the recent years, monthly-rent-with-variable-deposit structure has taken a substantial portion of rental contracts. This study attempts to analyze factors affecting changes in the ratio of Chonsei contract to Monthly rent with variable deposit contract from an investor’s viewpoint. A theoretical model is developed accounting for financial borrowing constraint, and empirical models are estimated with standard time series techniques. Empirical results show that the expected house price appreciation rate, Chonsei-to-monthly-rent conversion rate, and ratio of sale price to Chonsei deposit are statistically significant explanatory variables. While Chonsei-to-monthly-rent conversion rate negatively affects the ratio of Chonsei to monthly-rent-with-variable-deposit contract, the expected house price appreciation rate and the ratio of sale price to Chonsei deposit positively influence the ratio between Chonsei to monthly-rent-with-variable-deposit contracts.

CR REITs 주식가격 결정요인에 관한 연구

심종원(Shim Jong Won),정의철(Chung Eui-Chul) 대한국토·도시계획학회 2007 國土計劃 Vol.42 No.1

To analyze which factors critically affect the stock prices of REITs, we develop a modified model for REITs pricing based on a dividend pricing model and estimate the determinants of the stock prices of REITs using a sample of CR REITs traded in Korea Stock Exchange Market. Our estimation method(TSCS) fully takes account of heterogeneity of the REITs stocks and cross-sectional correlation of error terms. Estimation results show that the price of REITs is negatively affected by the prices of other financial assets such as corporate stocks and bonds and positively affected by rents from the tenants of properties managed by the REITs. This partly implies that the dividend pricing model is appropriate for the valuation of CR REITs in Korea. Also, the price of REITs is influenced by the characteristics of the properties. Our results show that the number of properties consisting of a REIT negatively affects the price and the price of a REIT is higher when the properties of a REIT are composed of buildings for different uses.