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.

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>

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.

Consumable Approaches of Polysilicon MEMS CMP

Sungmin Park,박범영,정해도,김형재,Sukhoon Jeong,Moonki Jeong 한국전기전자재료학회 2006 Transactions on Electrical and Electronic Material Vol.7 No.4

Chemical-mechanical polishing (CMP), one of the dominant technology for ULSI planarization, is used to flatten the micro electro-mechanical systems (MEMS) structures. The objective of this paper is to achieve good planarization of the deposited film and to improve deposition efficiency of subsequent layer structures by using surface-micromachining process in MEMS technology. Planarization characteristic of poly-Si film deposited on thin oxide layer with MEMS structures is evaluated with different slurries. Patterns used for this research have shapes of square, density, line, hole, pillar, and micro engine part. Advantages of CMP process for MEMS structures are observed respectively by using the test patterns with structures larger than 1um line width. Preliminary tests for material selectivity of poly-Si and oxide are conducted with two types of silica slurries: ILD1300TM and Nalco2371TM. And then, the experiments were conducted based on the pretest. A selectivity and pH adjustment of slurry affected largely step heights of MEMS structures. These results would be anticipated as an important bridge stone to manufacture MEMS CMP slurry.

Transition behavior of asymmetric polystyrene-<i>b</i>-poly(2-vinylpyridine) films: A stable hexagonally modulated layer structure

Park, Sungmin,Koo, Kyosung,Kim, Kyunginn,Ahn, Hyungju,Lee, Byeongdu,Park, Cheolmin,Ryu, Du Yeol Elsevier 2015 Polymer Vol.60 No.-

<P><B>Abstract</B></P> <P>The phase transitions in the films of an asymmetric polystyrene-<I>b</I>-poly(2-vinylpyridine) (PS-<I>b</I>-P2VP) were investigated by grazing incidence small-angle X-ray scattering (GISAXS) and transmission electron microscopy (TEM). Compared with the sequential transitions in the bulk, hexagonally perforated layer (HPL) – gyroid (GYR) – disorder (DIS) upon heating, the transitions in film geometry were dramatically changed with decreasing thickness due to the growing preferential interactions from substrate, resulting in a thickness-dependent transition diagram including four different morphologies of hexagonally modulated layer (HML), coexisting (HML and GYR), GYR, and DIS. Particularly in the films ≤10<I>L</I> <SUB> <I>o</I> </SUB>, where <I>L</I> <SUB> <I>o</I> </SUB> is <I>d</I>-spacing at 150 °C, a stable HML structure was identified even above the order-to-disorder transition (ODT) temperature of the bulk, which was attributed to the suppressed compositional fluctuations by the enhanced substrate interactions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase transitions in the bulk and films of asymmetric polystyrene-<I>b</I>-poly(2-vinylpyridine). </LI> <LI> Significant change in transitions of the films with decreasing film thickness. </LI> <LI> New observation of hexagonally modulated layer (HML) morphology in film geometry. </LI> <LI> A stable HML structure extended over the entire temperature range in the films ≤10<I>L</I> <SUB> <I>o</I> </SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Bio-based Vitrimer for Sustainable Digital Light Processing (DLP) 4D Printings

Sungmin Park 한국표면공학회 2023 한국표면공학회 학술발표회 초록집 Vol.2023 No.11-1

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>

Risk Factors Affecting Breast Cancer-related Lymphedema: Serial Body Weight Change During Neoadjuvant Anthracycline Plus Cyclophosphamide Followed by Taxane

Park, Sungmin,Lee, Jeong Eon,Yu, Jonghan,Paik, Hyun-June,Ryu, Jai Min,Kim, Isaac,Bae, Soo Youn,Lee, Se Kyung,Kim, Seok Won,Nam, Seok Jin,Kim, Eun-Kyu,Kang, Eunyoung,Yang, Eun Joo Elsevier 2018 Clinical breast cancer Vol.18 No.1

<P><B>Abstract</B></P> <P><B>Introduction</B></P> <P>The aim of our study was to analyze the risk of lymphedema (LE) according to the clinicopathologic factors and to investigate the serial change in body weight during neoadjuvant anthracycline plus cyclophosphamide followed by taxane and its correlation with the incidence of LE.</P> <P><B>Patients and Methods</B></P> <P>We performed a retrospective 2-center study of 406 patients who had undergone neoadjuvant chemotherapy (NAC) followed by surgery from 2007 to 2014. The regimen included 4 cycles of anthracycline plus cyclophosphamide, followed by 4 cycles of taxane. We investigated the presence and degree of LE using a telephone questionnaire assessment. Weight changes were calculated at each cycle of NAC, and the baseline and preoperative body weights were used to calculate the rate of change to account for the change in weight before and after NAC.</P> <P><B>Results</B></P> <P>Of the 406 patients, 270 answered the questionnaires, of whom 97 (35.9%) experienced LE. The increase in body weight was significant during the 4 cycles of taxane, but the change in weight was not significant during the 4 cycles of anthracycline plus cyclophosphamide. The change in body weight was most significant just after the fourth cycle of taxane (<I>P</I> < .001). The body mass index (BMI) was an independent factor of LE occurrence on multivariate analysis. However, the change in body weight was not a significant factor for the incidence of LE.</P> <P><B>Conclusion</B></P> <P>Because a BMI ≥ 25 kg/m<SUP>2</SUP> was an independent factor of LE occurrence on multivariate analysis, patients with a preoperative BMI ≥ 25 kg/m<SUP>2</SUP> should be closely monitored for LE given their increased risk, and monitoring and education should be initiated before surgery and continued throughout the course of NAC.</P>

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>

Input Impedance and Current Feedforward Control of Single-Phase Boost PFC Converters

Sungmin Park,Sung-Yeul Park,Ali M. Bazzi 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.3

The combination of voltage feedforward and feedback control is a conventional approach for correcting the power factor in single-phase ac-dc boost converters. The feedback duty ratio increases significantly with an increase of the line frequency and input inductance. Therefore, the performance of the conventional approach is highly dependent on the bandwidth of the feedback controller. As a result, the input power quality can be significantly exacerbated due to uncompensated duty ratios if the feedback controller is limited. This paper proposes an input impedance and current feedforward control method to reduce the control portion of the feedback controller. The findings in this paper are 1) the theoretical derivation and analysis of variations of line frequency and input inductance on a power factor correction approach, 2) guaranteed consistent performance in a wide range of conditions, and 3) that a low switching frequency can be utilized by the proposed method. A MATLAB/Simulink model and a 1.2kW dual boost converter are built to demonstrate the effectiveness of the proposed method.