Instabilities in polymeric films of micro and nano scale

주상우 한국고분자학회 2011 한국고분자학회 학술대회 연구논문 초록집 Vol.2011 No.1

2P-109 Self-healing Hydrogels Based on the Lysine and Sodium Alginate by Imine Crosslinking Reaction

주상우,정다함,김선목,정선호 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Self-healing hydrogels have drawn significant attention because it can result in longer lifespans and more applications than classical hydrogels. Here, a self-healable hydrogel was formed via reversible imine formation between aldehyde groups of oxidized sodium alginate (OSA) and amino groups of Lysine. We also added the functionalized β-cyclodextin (βCD) into the gel to confer new functionality. The structure and the mechanical performances of hydrogels were characterized by FT-IR, SEM, a rheometer, and a tensile testing machine. Also, drug delivery of the hydrogels was performed to investigate potential use in biomedical field.

조리과정에서 생성된 미세먼지의 크기분포 특성

주상우,지준호,Joo, Sang-Woo,Ji, Jun-Ho 한국입자에어로졸학회 2020 Particle and Aerosol Research Vol.16 No.1

The characteristics of particulate matter made from daily cooking at a Korean residential apartment house with three dwellers had been investigated for about 3 months. All data were recorded by an optical particle counter every minute at the kitchen. Types of cooking such as boiling, frying, and grilling that performed in the house were listed. Boiling only was used in 32% cases among total 234 meals. Frying and grilling were 14% and 11%, respectively. From an initial indoor particulate matter smaller than 10 ㎛ in diameter, the increases due to cooking are reported by size. In case of boiling, PM at 1-10 ㎛ size and under 1 ㎛ size little increased. Normally, particles from oil or combustion in a process of frying or grilling increased indoor PM. In a case of grilling, particle mass concentration in a region of 1-10 ㎛ in diameter increased as much as 295 ㎍/㎥. Mass concentration of particles smaller than 1 ㎛ increased as much as 33 ㎍/㎥.

pH-Dependent Surface-enhanced Raman Scattering Analysis of Maleimide and Succinimide on Ag Nanocolloidal Surfaces

주상우 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.9

The adsorption structure and binding of maleimide (MI) and succinimide (SI) on silver nanocolloidal surfaces have been comparatively investigated by means of pH-varied surface-enhanced Raman scattering (SERS). The two molecules appeared not to adsorb onto Ag surfaces at pH values below 5. The appearance of a ring ν (CH) band at ~3100 cm−1 denoted the standing geometry of MI’s aromatic ring on Ag. The absence or weakness of in-plane vibrational modes of MI and SI also supported a perpendicular orientation of MI and SI on Ag from the electromagnetic selection rule. Density functional theory (DFT) calculations were employed to examine the vibrational frequencies of MI’s and SI’s neutral and anionic states.

A new hydrodynamic instability in ultra-thin film flowsinduced by electro-osmosis

주상우 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.2

A new hydrodynamic instability is identified for a nanofluidic flow. The flow analyzed is an electro-osmotic flow of a thin liquid layer, bounded below by a solid substrate and above by an inert gas. The Debye-Hűckel approximation is used for the potential distribution, and the interface with the gas is treated as a moving boundary. The stability analysis shows that the flow is always unstable to small-wavenumber disturbances, and the instability is accompanied by interface deformations. Neutral stability bounds due to the capillary cut-off are presented in parametric spaces for the electric field strength and the Debye length of the electrolyte.

황사 발생시 아파트 실내에서 미세먼지 크기별 농도 특성

주상우,지준호,Joo, Sang-Woo,Ji, Jun-Ho 한국입자에어로졸학회 2019 Particle and Aerosol Research Vol.15 No.1

본 연구에서는 국내에서 가장 일반적인 유형의 주택으로서 3인 가구가 거주하는 공급면적 $117.69m^2$의 일반형 아파트를 측정 주택으로 선정하여 실증 측정을 진행하였다. 황사 발생이 포함된 3일 측정기간 동안 미세먼지 변화 특성을 관찰하여 분석하였다. 관측된 미세먼지($PM_{10}$)를 상대적으로 큰 먼지($PM_{10-2.5}$)와 초미세먼지($PM_{2.5}$)로 나누어 대기와 실내의 먼지의 농도변화를 분석하였다. 연구 결과로 재실자의 활동이 없는 외출이나 취침 기간에는 주택의 침기 특성을 확인할 수 있었다. 미세먼지 중 상대적으로 큰 $PM_{10-2.5}$ 크기 입자는 외기의 풍속이 5 m/s까지 증가하여 침기량이 증가해도 대기 농도 대비 실내 농도비가 7% 이하인 반면, $PM_{2.5}$의 경우 외기 속도가 5 m/s까지 증가하면 50% 이상으로 증가하였다. 황사가 심한 대기 상태에도 본 연구의 측정 주택의 경우 실내 $PM_{10-2.5}$는 시평균$15{\mu}g/m^3$로 대기 농도의 5% 수준으로 일상 조건과 비슷했다. 재실자의 활동이 있는 경우에는 미세먼지 중 초미세먼지를 제외한 상대적으로 큰 먼지는 자연환기와 실내 사람의 움직임과 같은 행동 영향이 지배적이었다. 실내 $PM_{10-2.5}$ 농도는 대기 농도가 낮은 경우에는 대기 농도의 약 50%를 차지하는 경우도 있었다. 재실자의 활동 중, 초미세먼지의 발생이 클 것으로 예상되는 굽기나 튀기기가 포함된 조리나 실내 흡연이 없었기 때문에, 재실자가 없는 경우와 마찬가지로 초미세먼지는 실내 농도가 실외 농도의 추이에 따라 함께 변동하는 양상을 보였다. 외부공기가 침기에 의해 창틈, 문틈으로 유입되는 과정에서 초미세먼지는 약 30~40% 정도가 제거되고 실내로 많은 비율이 유입되기 때문에 실외 초미세먼지의 실내에 대한 영향이 컸다. 본 연구의 분석 데이터는 측정이 이루어진 대표 주택에 해당하는 것으로, 새로 지어진 기밀 성능이 높은 신축 아파트나 침기가 상대적으로 클 것으로 예상되는 오래된 단독주택에서는 다른 특성이 나타날 것으로 예상되므로, 이에 대한 추가적인 연구가 필요하다고 생각된다. It is recommended for the public to stay at home and to close the doors and windows when a high-particulate-matter environment such as a yellow sand event occurs outside. However, there are lack of empirical studies describing how much outdoor PM infiltrates into a closed house and how much indoor PM an inhabitant is exposed to during the period. In this study, the $PM_{10}$ and $PM_{2.5}$ were measured at the kitchen in an apartment house by an optical particle counter for 3 days including a yellow sand event. The outdoor PMs and the outdoor wind speeds were referred from surrounding weather stations. We analyzed the penetration of $PM_{10-2.5}$ and $PM_{2.5}$ at the test house against the outdoor wind speed supposed corresponding to the change of air exchange rate. In addition, the effect of an indoor activity on change in the indoor PM was investigated. In result, the indoor $PM_{10-2.5}$ was very low even a yellow sand event occurred outside; rather, a contribution of indoor activities to increase in $PM_{10-2.5}$ was higher. In contrast, the indoor $PM_{2.5}$ fluctuated following the outdoor $PM_{2.5}$ trend at high wind speeds or remained almost constant at low wind speed.

국내 실내환경의 부유진균 연구 동향 및 농도분포

주상우,양성익,윤성원,김경환,조은민,장석원,조용성,이철민 한국실내환경학회 2013 한국실내환경학회지 Vol.10 No.1

The objective of this study is to support an environmental policy related to the improved control of indoor airborne fungi in Korea. We reviewed 15 articles published in Korea to analyse the trend of airborne fungi level in indoor environment of various public facilities. The maximum mean concentrations of total airborne fungi in hospital and kindergarten were 1447 CFU/㎥ and 1259 CFU/㎥, respectively. We concluded that policy determination are urgently required to guide a proper management on airborne fungi in Korea.

Infrared Spectrum of the Methyl Cation CH3+ in the 7 m region

주상우,T. Oka 한국천문학회 2008 天文學會報 Vol.33 No.2

악취센서로서 전자코의 최근 개발현황

주상우,박상진 한국냄새환경학회 2006 실내환경 및 냄새 학회지 Vol.5 No.3

This review presents the recent developments in electronic noses (E-noses). E-noses based on metal oxide semiconductors, conducting polymers, quartz crystal microbalance and electrochemical methods have been examined with regard to several aspects, from the basic principles to the application of new products, as olfactometry sensors. E-noses consist of an array of chemical sensors, and are currently employed in the analysis of odorous compounds as well as for common gas detection. Various data analyses have been employed to establish patterns of recognition and classification techniques. Future trends and areas of application for e-noses have also been introduced and are summarized within the text. 최근 전자코시스템의 개발현황에 대해서 정리하였다. 금속 산화물 반도체, 전도성 고분자, 수정미세저울 및 전기화학법의 기초원리부터 새로운 상품에 대해서 알아봤다. 전자코시스템의 어레이 시스템에 대해서 알아보고 악취물질 분석에 사용되는 방법에 대해서 조사했다. 패턴인식과 분류방법을 통해서 데이터 분석을 하는 방법에 대해서도 정리했다. 전자코 시스템의 앞으로 전망과 응용분야에 대해서도 요약했다.

국내 아파트의 미세먼지 유입 특성

주상우,지준호,Joo, SangWoo,Ji, JunHo 한국입자에어로졸학회 2019 Particle and Aerosol Research Vol.15 No.4

Infiltration characteristics of airborne particulate matter had been investigated in real-life for about 90 days over 2 years in a Korean apartment building where a 3-person household had lived and the exclusive private area was 84.9 ㎡. Airtightness was measured by fan depressurization, and the ACH₅₀ was 2.41 times per hour. In and outdoor particle concentrations were measured by optical particle counters. Infiltration factors and filtration efficiencies of the house, which reflect the removal of outdoor particles penetrating building envelope and the deposition inside a building, were obtained from data screened based on an empirical evaluation process. Infiltration factor of fine particles showed a range from about 42% at 0.4 m/s of wind speed to 72% at 4.2 m/s of wind speed with closed windows and doors. Filtration efficiency was like a MERV 13 grade filter with an open window outside at a balcony at low outdoor wind speed under 1 m/s. The grade decreased to MERV 11 by opening another outside window at the other balcony. Filtration efficiencies decreased as much as 29% in average at a range of 0.3~2.5 ㎛.