도시 지역에서 토지 피복에 따른 열 변이 특성

박성애,공학양,김승현,박성민,신영규,Park, Sung-Ae,Kong, Hak-Yang,Kim, Seung-Hyun,Park, Sungmin,Shin, Young-Kyu 응용생태공학회 2016 Ecology and resilient infrastructure Vol.3 No.1

본 연구는 수원시 도심에 위치한 도시공원인 효원공원을 대상으로 여름철 대기온도 저감효과를 확인하고, 공원을 구성하는 서로 다른 피복유형별 특성을 파악하기 위하여 열 환경을 실측하고 분석하였다. 도시공원의 여름철 대기온도저감효과는 도심주거지 (매탄동) 대비 평균 4.4-4.5%로 통계적으로 유의하였고 (p< 0.001), 수원시의 외곽주거지 (상광교동) 보다는 약 0.8% 낮은 수준이었다. 도시공원 내 피복유형 (보도 블럭, 잔디 식재지, 소나무-잔디 식재지, 수목 차광지 및 혼합림 조경지)에 따른 열환경은 자연소재의 유형일수록 일평균기온, 일최고기온, 여름일수가 낮은 경향을 보였다. 그러나, 일최저기온 및 열대야일수는 피복유형에 따른 상관관계가 뚜렷하게 나타나지 않았다. 오후시간대 (13:00-15:00)에 혼합림 조경지, 수목 차광지, 소나무-잔디 식재지의 불쾌지수 (DI), 습구흑구온도 (WBGT) 및 열지수 (HI)의 평균값이 보도 블록과 잔디 식재지보다 낮아서 자연소재의 피복 유형의 열쾌적성이 양호한 것으로 나타났다. 그러나 각 지수에 대한 등급은 모든 피복 유형에서 '가장 높음' 또는 '주의' 단계로 동일하였다. 한편 오전 (06:00-08:00)에는 토지 피복유형별 열쾌적성에 차이가 없었다. 결론적으로 도시에서 열 환경을 개선하기 위하여는 초지, 숲 및 개방 지역의 토지 피복 유형을 증가하여야 한다. This study was conducted to analyze the effect of the different land covers of an urban park (Hyowon park) in downtown Suwon on the urban thermal variations during a hot summer. The effect of the air temperature reduction in the urban park was 4.4%-4.5% for the downtown residence (Maetan-dong). This value was about 0.8% lower than that of the outskirts residence (Sanggwanggyo-dong). The daily mean temperature, daily maximum temperature, summer day and heat wave frequency were measured under the different land covers (cement-block, grass, pine-grass, shading area and mixed forest) showed these values generally decreased under natural land cover types. Daily minimum temperature and tropical night frequency didn't seem to correlate with the land cover types. Means of thermal comfort indices (wet bulb globe temperature, heat index and discomfort index) in the shading area, mixed forest and the pine-grass types were lower than those of cement block and grass types. However the levels of those indices were equal to 'very high' or 'caution' levels in the afternoon (13:00-15:00). In the morning (06:00-08:00), thermal comfort indices of the urban park didn't correlate with land cover types. Therefore, to reduce heat stress and to improve the thermal comfort in urban parks, an increase in the area of natural land cover such as grass, forest and open spaces is required.

a-axis Contribution to the Polarization Value in (117)/(200)-Oriented Bi3.75La0.25Ti3O12 Thin Films Deposited on Pt(111)/Ti/SiO2/Si Substrate

Sungmin Park,Jaemoon Pak,Doyoung Park,Hyeonsik Cheong,Gwangseo Park 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.2

The a-axis contribution to the polarization value in Bi3.75La0.25Ti3O12 (BLT0.25) thin films deposited on Pt (111)/Ti/SiO2/Si was investigated. The films were prepared by using a chemical solution deposition method. In order to examine the internal vibration modes of the BLT0.25 thin films, we employed Raman spectroscopy at room temperature with a 514.5 nm Ar+ laser as the excitation source. The films annealed at 750℃ and 800℃ have preferentially (117) and (200) orientations and the proportion of grains with those two orientations in the films was estimated from the X-ray peak intensity. The intensity of the (117) peak increases (over 3.5 times) and the peak position is shifted to lower 2θ angles, largely reflecting in the increases of the number of (117)-oriented grains and in the lattice constant c as the annealing temperature increases. The increase in the lattice constant c can also be supported by the enhancements of the 566 and the 618 cm-1 Raman peaks, which demonstrates an enlargement of TiO6 symmetric stretching mode. In addition, the lattice constant a increases from 5.3675 A to 5.3957A as the annealing temperatures is increased from 750℃ to 800℃, in spite of the fact that the two polarization curves are quite similar. Thus, the dominant axis contributing to the total polarization value is the a-axis. The a-axis contribution to the polarization value in Bi3.75La0.25Ti3O12 (BLT0.25) thin films deposited on Pt (111)/Ti/SiO2/Si was investigated. The films were prepared by using a chemical solution deposition method. In order to examine the internal vibration modes of the BLT0.25 thin films, we employed Raman spectroscopy at room temperature with a 514.5 nm Ar+ laser as the excitation source. The films annealed at 750℃ and 800℃ have preferentially (117) and (200) orientations and the proportion of grains with those two orientations in the films was estimated from the X-ray peak intensity. The intensity of the (117) peak increases (over 3.5 times) and the peak position is shifted to lower 2θ angles, largely reflecting in the increases of the number of (117)-oriented grains and in the lattice constant c as the annealing temperature increases. The increase in the lattice constant c can also be supported by the enhancements of the 566 and the 618 cm-1 Raman peaks, which demonstrates an enlargement of TiO6 symmetric stretching mode. In addition, the lattice constant a increases from 5.3675 A to 5.3957A as the annealing temperatures is increased from 750℃ to 800℃, in spite of the fact that the two polarization curves are quite similar. Thus, the dominant axis contributing to the total polarization value is the a-axis.

Electrically Tunable Soft-Solid Block Copolymer Structural Color

Park, Tae Joon,Hwang, Sun Kak,Park, Sungmin,Cho, Sung Hwan,Park, Tae Hyun,Jeong, Beomjin,Kang, Han Sol,Ryu, Du Yeol,Huh, June,Thomas, Edwin L.,Park, Cheolmin American Chemical Society 2015 ACS NANO Vol.9 No.12

<P>One-dimensional photonic crystals based on the periodic stacking of two different dielectric layers have been widely studied, but the fabrication of mechanically flexible polymer structural color (SC) films, with electro-active color switching, remains challenging. Here, we demonstrate free-standing electric field tunable ionic liquid (IL) swollen block copolymer (BCP) films. Placement of a polymer/ionic liquid film-reservoir adjacent to a self-assembled poly(styrene-<I>block</I>-quaternized 2-vinylpyridine) (PS-<I>b</I>-QP2VP) copolymer SC film allowed the development of red (R), green (G), and blue (B) full-color SC block copolymer films by swelling of the QP2VP domains by the ionic liquid associated with water molecules. The IL–polymer/BCP SC film is mechanically flexible with excellent color stability over several days at ambient conditions. The selective swelling of the QP2VP domains could be controlled by both the ratio of the IL to a polymer in the gel-like IL reservoir layer and by an applied voltage in the range of −3 to +6 V using a metal/IL reservoir/SC film/IL reservoir/metal capacitor type device.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-12/acsnano.5b05234/production/images/medium/nn-2015-052345_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b05234'>ACS Electronic Supporting Info</A></P>

Identification of DEA Determinant Input-Output Variables

Sungmin Park(박성민) 대한산업공학회 2014 대한산업공학회지 Vol.40 No.1

Electrical Properties of CeO2 Thin Films Grown on p-Si(100) Substrates by the Pulsed Laser Deposition method

Sungmin Park,박광서,Jaemoon Pak,Kuangwoo Nam 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III

CeO2 thin films on p-Si(100) were deposited by using Pulsed Laser Deposition(PLD) to study the structure and the electrical properties. (111) preferential orientation was observed by the X-ray diffraction -2 scan method. FWHM was increased as the deposition temperature decreased. Also, they had a granular type of grain for very well oriented films deposited at 760 C in vacuum. To investigate electrical properties, an Au/CeO2/Si/Al structure was fabricated. C-V characteristic and I-V characteristic were produced with a HP4194 impedance-gain analyzer and a Keithlely 617 electrometer. A strong increase of capacitance appeared at relatively low frequency (100 kHz), which can be explained by a frequency-dependent non-uniformity state generated at the interface between CeO2 and Si substrate. Especially, based on each C-V characteristic, VF B(flat band voltage)was slightly shifted toward negative bias, which means that fixed oxide charge and interface trapped charge exist. In addition, slight hysteretic behaviors of the C-V curve attributed to trapping effects were observed at all measured frequencies. Current density of the film showed different tendencies for positive and negative bias. The difference of current density between negative and positive bias was over 10.6 order. We will report on these electrical properties and discuss various defect states that may dominantly affect the CeO2/Si system.

State Estimation for Supervisory Monitoring of Substations

Sungmin Park,Eunjae Lee,Wonkun Yu,Heungjae Lee,Jeonghoon Shin IEEE 2013 IEEE transactions on smart grid Vol.4 No.1

<P>This paper introduces the application of state estimation to double bus double breaker distribution substations, which are typically used in the Korean power system, to improve the reliability of substation automation systems. In spite of the recent remarkable progress in the field of sensors and equipments, it is hard to detect device malfunctions or degraded devices automatically in the supervisory monitoring system. The object of the proposed system is not the state estimation itself, but its application to the supervisory detection of the malfunction or degradation of the devices. The supervisory monitoring process consists of a two step procedure-topology processing and normal state estimation. In a substation, the on-off states of the circuit breakers determine the topology. This paper mainly presents the topology processing expert system including the knowledge representation. The expert system is operated with a predefined period to identify and correct topological errors in the distribution substations. The proposed system is now in the field test stage in the Sanchung pilot substation and it will be applied to the next generation substation automation system in Korea.</P>

Efficient Cycle Time-Throughput Curve Generation Using Discrete Event Simulation

Sungmin Park 대한산업공학회 2001 대한산업공학회 춘계학술대회논문집 Vol.2001 No.4

Gyroid Structures in Solvent Annealed PS-<i>b</i>-PMMA Films: Controlled Orientation by Substrate Interactions

Park, Sungmin,Kim, Yeongsik,Lee, Wooseop,Hur, Su-Mi,Ryu, Du Yeol American Chemical Society 2017 Macromolecules Vol.50 No.13

<P>We investigated the orientation of gyroid structures in thin films of high-molecular-weight (HMW) polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) upon a solvent vapor annealing (SVA) process with tetrahydrofuran nonselective to the PS and PMMA blocks. During the SVA process, the swollen PS-b-PMMA films produced the gyroid structures that were developed through a cylindrical morphology from a poorly ordered structure. The interfacial interactions exerted by the substrates significantly influenced the orientation of cylinders, like the parallel and perpendicular orientations on the selective and neutral substrates, respectively, while the solvent vapor generated perpendicular cylinders at the surface. In the final formation of gyroid structures, we identified the two distinct [211] and [111] planes on the surface throughout the interior of the films, which were directed from cylinders on the selective and neutral substrates, respectively. To provide the insight of the molecular mechanisms taking place during the orderorder transition, we further performed coarse-grained simulations of a block copolymer model. Our results based on experiments and simulations suggest a simple route for the directed orientation of well-defined gyroid structures.</P>

A [2,2]paracyclophane triarylamine-based hole-transporting material for high performance perovskite solar cells

Park, Sungmin,Heo, Jin Hyuck,Cheon, Cheol Hong,Kim, Heesuk,Im, Sang Hyuk,Son, Hae Jung The Royal Society of Chemistry 2015 Journal of materials chemistry. A, Materials for e Vol.3 No.48

<▼1><P>We report a new hole transporting material (HTM) based on [2,2]paracyclophane triarylamine. Due to its higher charge mobility compared with spiro-OMeTAD, the solar cell device incorporating the new HTM achieved a high photovoltaic performance with a PCE of 17.6%.</P></▼1><▼2><P>We report the development of a novel hole transporting material (HTM), PCP-TPA, based on [2,2]paracyclophane. In comparison to the well-known HTM, spiro-OMeTAD, PCP-TPA could be prepared using a simple synthesis and showed a higher hole mobility due to effective intermolecular aggregation in the film state. When used as a HTM in perovskite solar cells, the power conversion efficiency reached 17.6%. PCP-TPA will potentially replace spiro-OMeTAD and advance the development of cost-effective and practical perovskite solar cells.</P></▼2>

Tailoring of Polymer Chains and Microstructure Characterization Using X-ray Scattering

Sungmin Park(박성민 ) 한국고분자학회 2020 한국고분자학회 학술대회 연구논문 초록집 Vol.45 No.2