시정 측정의 장비, 방법 및 대전지역 시정의 분석

소선섭,김시내,박수현 公州大學校 基礎科學硏究所 2003 自然科學硏究 Vol.10 No.-

본 논문은 대기 오염물질의 배출량이 많아지면서 대기의 혼탁도가 높아지고 이로 인해 시정이 악화됨을 규명하고자 하였다. 시정의 악화를 언급하기에 앞서 시정에 대해서 보다 명확하게 정의하였고, 대전지역의 시정 자료 값을 분석하여 대기의 오염이 얼마나 증가하였는가를 밝힘으로써 시정측정 장비 연구의 필요성을 강조하였다. In this Essay, we wished to examine closely that turbidity of air rised, visibility is worsened because the discharge amount of air contaminant increased. Before refer visibility for the worse, we defined more definitely about visibility, analyzed visibility value of DaeJon area, said how pollution of air increased, so emphasized necessity that we should have researched visibility monitoring method.

Effect of Sulfurization Temperature on Solution-Processed Cu2ZnSnS4 Thin Films.

Park, Si-Nae,Sung, Shi-Joon,Son, Dae-Ho,Kim, Dae-Hwan,Sim, Jun-Hyoung,Kang, Jin-Kyu American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.3

<P>Cu2ZnSnS4 (CZTS) solar cells are attracting significant attention as an alternative to CIGS (Culn1-xGa(x)S2) solar cells because of the non-toxic and inexpensive constituent elements of CZTS. Recently, solution-based deposition methods are being developed because they have advantages such as suitability for use in large-area deposition, high-throughput manufacturing, and a very short energy payback time with drastically lower manufacturing costs. In this work, we fabricated solution-based CZTS thin films and investigated them in order to observe the effects of sulfurization temperature on CZTS thin films. We confirmed the grain size, morphology, chemical composition, crystallinity, and electrical properties of CZTS thin films depending on various sulfurization temperatures.</P>

Effect of Morphology of Solution-Processed Precursor Films on Cu2ZnSnS4 Thin Film Solar Cells

Park, Si-Nae,Sung, Shi-Joon,Yang, Kee-Jeong,Kim, Dae-Hwan,Cho, Kuk Young,Kang, Jin-Kyu American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.10

<P>Solution-processed Cu2ZnSnS4 (CZTS) thin films are generally fabricated by sulfurization of CZTS precursor films. Therefore, the sulfurized CZTS thin films are closely affected by the thin film properties of the CZTS precursor films. In this work, we have investigated the correlation between the thin film properties of the CZTS precursor films prepared using a spin coating process and the morphology and photovoltaic properties of the sulfurized CZTS films. The morphology and thickness of spin-coated CZTS precursor films are controlled by a stepwise pre-annealing treatment, and are then varied according to the difference between the decomposition temperature of each component of the CZTS precursor solution and the temperature of the stepwise pre-annealing treatment. This can be attributed to the different removal behaviors of the components of the CZST precursor solution during the stepwise pre-annealing treatment. The morphology and thickness of the CZTS precursor films are closely related to the final properties of CZTS thin films after the sulfurization process. We also investigated the photovoltaic properties of the CZTS solar cells prepared from the CZTS precursor films with different thicknesses and morphologies. In this case, the size and density of CZTS grains are decisive factors for determining the photovoltaic properties of CZTS solar cells.</P>

Nanostructured p-type CZTS thin films prepared by a facile solution process for 3D p-n junction solar cells

Park, Si-Nae,Sung, Shi-Joon,Sim, Jun-Hyoung,Yang, Kee-Jeong,Hwang, Dae-Kue,Kim, JunHo,Kim, Gee Yeong,Jo, William,Kim, Dae-Hwan,Kang, Jin-Kyu The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.25

<P>Nanoporous p-type semiconductor thin films prepared by a simple solution-based process with appropriate thermal treatment and three-dimensional (3D) p-n junction solar cells fabricated by depositing n-type semiconductor layers onto the nanoporous p-type thin films show considerable photovoltaic performance compared with conventional thin film p-n junction solar cells. Spin-coated p-type Cu2ZnSnS4(CZTS) thin films prepared using metal chlorides and thiourea show unique nanoporous thin film morphology, which is composed of a cluster of CZTS nanograins of 50-500 nm, and the obvious 3D p-n junction structure is fabricated by the deposition of n-type CdS on the nanoporous CZTS thin films by chemical bath deposition. The photovoltaic properties of 3D p-n junction CZTS solar cells are predominantly affected by the scale of CZTS nanograins, which is easily controlled by the sulfurization temperature of CZTS precursor films. The scale of CZTS nanograins determines the minority carrier transportation within the 3D p-n junction between CZTS and CdS, which are closely related with the photocurrent of series resistance of 3D p-n junction solar cells. 3D p-n junction CZTS solar cells with nanograins below 100 nm show power conversion efficiency of 5.02%, which is comparable with conventional CZTS thin film solar cells.</P>

Controlled synthesis of (hk1) preferentially oriented Sb2Se3 rod arrays by co-evaporation for photovoltaic applications

Park, Si-Nae,Kim, Se-Yun,Lee, Sang-Ju,Sung, Shi-Joon,Yang, Kee-Jeong,Kang, Jin-Kyu,Kim, Dae-Hwan Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.45

<P>In this paper, we propose that the microstructural control of (<I>hk</I>1) preferentially oriented Sb2Se3 films from flat films to rod arrays can improve their photovoltaic efficiency by maximizing the carrier transport characteristics. We found that, during co-evaporation, there is a narrow substrate temperature window where the Sb2Se3 rod array can be formed with an (<I>hk</I>1) preferred orientation, thus maximizing the carrier transport characteristics. The substrate-temperature-dependent morphology of the Sb2Se3 films can be explained by nucleation and growth theory and the terrace-ledge-kink model. Dramatic changes in the (<I>hk</I>0) and (<I>hk</I>1) texture coefficients occur at 315 °C, and the critical temperature for obtaining the (<I>hk</I>1) preferentially oriented Sb2Se3 film is a substrate temperature of 315 °C. On the basis of the observed variation in the film microstructure and texture coefficient, the optimum Sb2Se3 rod array having an (<I>hk</I>1) preferred orientation is formed in a narrow range of substrate temperatures. As a result, we obtained an optimized Sb2Se3 thin-film rod array that shows effective carrier transportation. Further, the optimum fill factor, short circuit current, open circuit voltage, and efficiency of the Sb2Se3 device were observed in the Sb2Se3 rod array having an (<I>hk</I>1) preferred orientation, and the enhanced carrier transport characteristics are the main reason for the improved device properties. These results show that controlling the microstructure of Sb2Se3 allows improvements in the efficiency of (<I>hk</I>1) preferentially oriented Sb2Se3 films.</P>

Low-Cost Nanoporous Cu₂ZnSnS₄ Thin-Film Counter Electrode for Dye-Sensitized Solar Cells

Park, Si-Nae,Sung, Shi-Joon,Yang, Kee-Jeong,Kang, Jin-Kyu,Kim, Dae-Hwan American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.10

<P>The Cu2ZnSnS4 thin film is a well-known and promising electrode material to substitute for the expensive Pt counter electrode used in dye-sensitized solar cells. In this work, we have proposed a novel nanoporous Cu2ZnSnS4 thin film prepared by a simple and non-toxic process for use as the counter-electrode material. The Cu2ZnSnS4 thin film was easily prepared by a simple spin coating process using a sol-gel precursor that consists of metal chlorides and thiourea, followed by thermal annealing. By manipulating the thermal annealing conditions, a Cu2ZnSnS4 thin film with unique nanoporous morphology could be realized, and this film was very effective as the counter electrode owing to its large surface area. Because the size of Cu2ZnSnS4 nanograins was affected by the thermal annealing temperature, the scale of the nanoporous structures of the Cu2ZnSnS4 counter electrode, which significantly affects the photovoltaic characteristics of dye-sensitized solar cells, could be controlled by manipulating the annealing temperature. The structure and morphology of nanoporous Cu2ZnSnS4 thin films were characterized via X-ray diffraction and scanning electron microscopy analysis, and the photovoltaic performance of dye-sensitized solar cells based on the nanoporous Cu2ZnSnS4 counter electrode was also investigated. The nanoporous Cu2ZnSnS4 counter electrode exhibited a power conversion efficiency of 4.494% under 100 mW/cm(2) AM 1.5 simulated light, V-oc of 0.610 V, J(sc) of 10.46 mA/cm(2), and FF of 70.44%, and this power conversion efficiency was comparable to that of a conventional Pt counter electrode (5.719%) for the same device configuration.</P>

Fabrication and characterization of CuSbS₂ thin films from metal stacks prepared by vacuum process

Si-Nae PARK,Sang-Ju LEE,Shi-Joon SUNG,Yong Chan CHOI,Dae-Hwan KIM,Kee-Jeong YANG,Jin-Kyu KANG 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Peri-estrus activity and mounting behavior and its application to estrus detection in Hanwoo (Korea Native Cattle)

Si Nae Cheon,Geun Woo Park,Kyu Hyun Park,전중환 한국축산학회 2023 한국축산학회지 Vol.65 No.4

This study was conducted to investigate the change in activity and mounting behavior in Hanwoo (Korean Native Cattle) during the peri-estrus period and its application to estrus detection. A total of 20 Hanwoo cows were fitted with a neck-collar accelerometer device, which measured the location and acceleration of cow movements and recorded the number of instances of mounting behavior by the altitude data. The data were analyzed in three periods (24-, 6-, and 2-h periods). Blood samples were collected for 5 days after the prostaglandin F2α (PGF2α) injection, and the concentrations of estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone were determined by enzyme-linked immunosorbent assays. Activity and mounting behavior recorded over 2-h periods significantly increased as estrus approached and were more efficient at detecting estrus than over 24- and 6-h periods (p < 0.05). Endocrine patterns did not differ with the variation of individual cows during the peri-estrus period (p > 0.05). Activity was selected as the best predictor through stepwise discriminant analysis. However, activity alone is not enough to detect estrus. We suggest that a combination of activity and mounting behavior may improve estrus detection efficiency in Hanwoo. Further research is necessary to validate the findings on a larger sample size.

Correlation Between Chemical Composition and Efficiency of Cu₂ZnSnS₄ Solar Cells Prepared by a Solution Process

Park, Si-Nae,Sung, Shi-Joon,Kim, Dae-Hwan,Kang, Jin-Kyu American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.8

<P>Solution-based Cu2ZnSnS4 (CZTS) solar cells are attracting a lot of attention as a strong alternative to vacuum-based CZTS solar cells owing to their simple and low-cost process, large area deposition, and so on. Typically, the solution-based process consists of two steps: coating with precursor solution and annealing of the precursor films. Unlike vacuum-based deposition, the precursor solution contains unnecessary elements in order to form high quality precursor films, and thus, the precise control of the chemical composition of CZTS absorbers is essential for achieving highly efficient CZTS solar cells. In this work, we have investigated the correlation between chemical composition and efficiency of CZTS solar cells prepared by a spin coating method. The composition of the CZTS precursor solution is controlled in order to obtain optimized chemical composition of CZTS absorbers. Pre-annealing of CZTS precursor films is also varied to confirm the effect of thermal treatment on the chemical composition of CZTS absorbers. Due to the different thermal decomposition behaviors of metal precursors in CZTS precursor solutions, the chemical composition of CZTS absorbers are considerably affected by the pre-annealing temperature. The efficiency of CZTS solar cells is closely related to the chemical composition of CZTS absorbers and the CZTS solar cell with Cu/(Zn + Sn) = 0.75 and Zn/Sn = 1.10 exhibited J(SC), V-OC, FF, and efficiency of 0.58 V, 17.28 mA/cm(2), 52.1%, and 5.18%, respectively.</P>

연구논문 : 경제활동인구조사의 자료수집방법별 효과 분석: 응답자의 자료수집방법 선택효과를 중심으로

박시내 ( Si Nae Park ),최유성 ( Yu Seung Choi ),한승훈 ( Seung Hoon Han ) 한국조사연구학회 2014 조사연구 Vol.15 No.1

본 연구는 우리나라 및 해외 통계청의 노동력조사 자료수집방법의 경향을 파악하고, 경제활동인구조사의 자료수집방법별 모드효과 중 응답자의 자료수집방법 선택효과가 자료수집방법별 고용지표에 차이를 발생시키는지 여부를 알아보는 것을 목적으로 한다. 유럽연합(EU)이나 미국 등 주요 나라들과 마찬가지로 우리나라 역시 표본연동에 따라 혼합조사 방식으로 자료를 수집하고 있으며, 전자조사의 비중이 높아지고 있는 경향이 있었다. 본 연구결과에 따르면, 응답자의 자료수집방법 선택에 연령이나 교육정도 등의 변수들이 영향을 미치는 것으로 나타났다. 응답자의 자료수집방법 선택에 영향을 미치는 변수들을 통제하기 위해 반복비례가중법을 이용하여 가중치를 조정하였다. 가중치 조정 전에는 자료수집방법이 고용지표에 영향을 주었으나, 가중치조정 후에는 그 영향이 줄거나 없어졌다. The purpose of this study is to understand a trend of data collection modes of the Labour Force Surveys of both Korea and other countries, and to investigate whether the effect of respondent`s choice for data collection modes affects laborforce indicators. For the Labor Force Surveys, mixed-mode survey is commonly used to collect data in the most countries as well as Korea. We also found that the portion of electronic survey in the mixed-mode survey has been increasing. According to this study, gender, educational attainment, and other personal characteristics influence respondent`s choice for the data collection modes. To control the differences of the characteristics of respondents, we adjusted weight using iterative proportional weighting method. After adjustment of weight, the effect of labor force indicators by data collection modes diminished or disappeared.