• Title/Summary/Keyword: 분광 특성

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A Study on Material Characteristics and Manufacturing Techniques for Gold-granule Beads Excavated from the Neungsan-ri Temple Site in Buyeo (부여 능산리사지 출토 금제구슬의 재료학적 특성 및 제작기법 연구)

  • Yang, Soohyeon;Ro, Jihyun
    • Conservation Science in Museum
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    • v.26
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    • pp.67-82
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    • 2021
  • Two golden beads (Buyeo 5336) housed at the Buyeo National Museum were discovered in 1993 near the site of an ancient workshop in Neungsan-ri in Buyeo-gun, Chungcheongnam-do Province. These rare examples from the Baekje Kingdom of an application of granulation have maintained their original form intact, and thus serve as important materials for the investigation of production techniques applied. This study analyzed the composition of the golden beads using a portable X-ray fluorescence analyzer, a stereo microscope, and a scanning electron microscope with an energy dispersive X-ray spectrometer. The manufacturing technique was examined through the observation of the micro-shape and the surface condition and by a composition analysis of the joint part. In both beads, a hole was pierced in a hollow body and the bead was decorated with golden wires around the hole and gold granules in other parts. In some areas, golden granules had been attached to the gold plate and golden wires were then placed over the granules. The purity of both the wires and the granules was analyzed as 23.6 - 23.7K. A high copper content was detected in some of the parts where the granules were attached. The findings of a previous reproduction experiment and study of production methods suggest that the beads were made using the copper diffusion technique.

Development of the Automatic Method for Detecting the National River Networks Using the Sentinel-2 Satellite Imagery -A Case Study for Han River, Seoul- (Sentinel-2 위성영상을 활용하여 국가하천망 제작을 위한 자동화 기술 개발 -서울시 한강을 사례로-)

  • KIM, Seon-Woo;KWON, Yong-Ha;CHUNG, Youn-In;CHOUNG, Yun-Jae
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.2
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    • pp.88-99
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    • 2022
  • The river network is one of the essential topographical characteristics in river management. The river network which as previously constructed by the ground surveying method has recently begun to be efficiently constructed using the remote sensing datasets. Since it is difficult to remove these obstacles such as bridges in the urban rivers, it is rare to construct the urban river networks with the various obstacles. In this study, the Sentinel-2 satellite imagery was used to develop the automatic method for detecting the urban river networks without the obstacles and with the preserved boundaries as follows. First, the normalized difference water index image was generated using the multispectral bands of the given Sentinel-2 satellite imagery, and the binary image that could classify the water body and other regions was generated. Next, the morphological operations were employed for detecting the complete river networks with the obstacles removed and the boundaries preserved. As a result of applying the proposed methodology to Han River in Seoul, the complete river networks with the obstacles removed and the boundaries preserved were well constructed.

Characterization of fine particulate matter during summer at an urban site in Gwangju using chemical, optical, and spectroscopic methods (화학적·광학적·분광학적 방법을 이용한 광주 도심지역 여름철 초미세먼지의 특성)

  • Son, Se-Chang;Park, Tae-Eon;Park, Seungshik
    • Particle and aerosol research
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    • v.17 no.4
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    • pp.91-106
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    • 2021
  • Daily PM2.5 was collected during summer period in 2020 in Gwangju to investigate its chemical and light absorption properties. In addition, real-time light absorption coefficients were observed using a dual-spot 7-wavelength aethalometer. During the study period, SO42- was the most important contributor to PM2.5, accounting for on average 33% (10-64%) of PM2.5. The chemical form of SO42- was appeared to be combination of 70% (NH4)2SO4 and 30% NH4HSO4. Concentration-weighted trajectory (CWT) analysis indicated that SO42- particles were dominated by local pollution, rather than regional transport from China. A combination of aethalometer-based and water-extracted brown carbon (BrC) absorption indicated that light absorption of BrC due to aerosol particles was 1.6 times higher than that due to water-soluble BrC, but the opposite result was found in absorption Ångström exponent (AAE) values. Lower AAE value by aerosol BrC particles was due to the light absorption of aerosol BrC by both water-soluble and insoluble organic aerosols. The BrC light absorption was also influenced by both primary sources (e.g., traffic and biomass burning emissions) and secondary organic aerosol formation. Finally the ATR-FTIR analysis confirmed the presence of NH4+, C-H groups, SO42-, and HSO42-. The presence of HSO42- supports the result of the estimated composition ratio of inorganic sulfate ((NH4)2SO4) and bisulfate (NH4HSO4).

Characterization of fine organic aerosols from biomass burning emissions using FTIR method (분광학적 방법을 이용한 바이오매스 연소 배출 유기 입자의 화학적 특성)

  • Son, Se-Chang;Park, Tae-Eon;Park, Seungshik
    • Particle and aerosol research
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    • v.17 no.4
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    • pp.125-132
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    • 2021
  • Fresh PM2.5 smokes emitted from combustion of four biomass materials (pellet, palm fruit fiber (PFF), PKS, and sawdust) in a laboratory-controlled environment were characterized using an attenuated total reflectance-fourier transform infrared (ATR-FTIR) technique. In smoke samples emitted from combustion of pellets, PFF and PKS, which is being used as boiler fuels for greenhouses in rural areas, the organic carbon/elemental carbon (OC/EC) ratios in PM2.5 were very high (14.0-35.5), whereas in sawdust smoke samples they were significantly low (<4.0) due to the combustion method close to flaming combustion. ATR-FTIR analysis showed that OH(3400-3250 cm-1), CH3(2958-2840 cm-1), CH2(2910 cm-1 and 2850 cm-1), ketone(1726-1697 cm-1), C=C(1607-1606 cm-1 and 1515-1514 cm-1), lignin (1463-1462 cm-1 and 1430-1428 cm-1) and -NO2(1360-1370 cm-1) peaks were identified in all biomass burning (BB) smoke samples. However, additional peaks appeared depending on the type of biomass. Among the four types of biomass materials, an additional peak of the methylene group CH3(2872-2870 cm-1) appeared only in PFF and PKS smoke samples, and a peak of C=O(1685 cm-1) was also confirmed. And in the case of PKS smoke samples, a peak of aromatic C=C(1593 cm-1 and 1476 cm-1) that did not appear in other BB samples was also observed. This indicates that the molecular structure of organic compounds emitted during BB differs depending on the type of biomass materials. The results of this study are expected to provide valuable information to more specifically reveal the effect of BB on PM2.5 collected in the atmospheric environment.

Fermentation Efficiency and Effect on Morphological Change of Nitrogen and Phosphorous with the Litter Types of Cowshed (우사의 깔짚 종류에 따른 발효 효율과 질소와 인의 형태 변화에 미치는 영향)

  • Ryoo, Keon Sang
    • Journal of the Korean Chemical Society
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    • v.66 no.2
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    • pp.86-91
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    • 2022
  • The manure made of chaff and sawdust as litter was collected separately at a cowshed of a livestock farm in Andondg city. The fermentation efficiency of excreta is greatly influenced by the type and characteristics of litter and a factor to be considered for reducing N and P, the causes of eutrophication. Changes in weight with temperature and constituents of sample were examined using TG-DTA and XRF, respectively. NO2-, NO3-, and PO43- ions and NH4+, T-P and T-N eluted from manure by rain were analyzed using ion chromatograph and UV/Vis spectrometry, respectively. As a result, the fermentation efficiency of excreta in sawdust manure is three times higher as compared with chaff manure. The higher the fermentation efficiency, ammonia nitrogen was highly de-nitrogenated and organic phosphorous were also changed into phosphorous ions. Furthermore, phosphorous ions can be removed by transforming insoluble salts such as calcium phosphate (CaHPO4·3H2O) and struvite (NH4MgPO4·6H2O) with addition of Ca and Mg.

A Study on the Effect on UV Exposure in Coastal Buildings (연안건축물의 자외선 노출에 따른 안전성 연구)

  • Kim, Taehwan;Uh, Jesun
    • Journal of the Society of Disaster Information
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    • v.17 no.2
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    • pp.195-205
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    • 2021
  • Purpose: The ultraviolet reflectance and transmittance of coastal building materials are one of the important factors of ultraviolet radiation in and out of coastal building. In this research, the ultraviolet spectral reflectance of many kinds of building materials was measured. Also, the relationships with the lightness, roughness, and chromaticity, which are surface characteristics, were reviewed and suggested. Method: In this study, according to the CIE classification, the ultraviolet region was defined as short-wavelength region UV-C(10nm~280nm), medium-wavelength region UV-B (280-315 nm), and long-wavelength region UV-A (315-400nm), and the visible light region was defined as (400nm~780nm). Spectrophotometer was used to continuously measure the reflectance from the ultraviolet region to the visible light region. Results: From the measurement results, the ultraviolet reflectance on Wood was shown to be about Visible 55-68%, UV-A* 7-12%, and UV-B 4-5%. Wall tiles are about Visible18-40%, UV-A* 8-20%, and UV-B* 7-8%. That on concrete was shown to be about Visible 37%, UV-A* 28%, and UV-B*19%. Conclusion: The ultraviolet reflectance can be estimated by visible reflectance. Also, it is important to select a variety of materials according to the application when blocking UV.

Analysis of calcium fluoride single crystal grown by the czochralski method (초크랄스키 방법으로 성장한 CaF2 단결정 분석)

  • Lee, Ha-Lin;Na, Jun-Hyuck;Park, Mi-Seon;Jang, Yeon-Suk;Jung, Hea-Kyun;Kim, Doo-Gun;Lee, Won-Jae
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.32 no.6
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    • pp.219-224
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    • 2022
  • CaF2 single crystal has a large band gap (12 eV), and it is used for optical windows, prisms, and lenses due to its excellent transmittance in a wide wavelength range and low refractive index. Moreover, it is expected to be one of the materials for ultraviolet transmissive laser optical components. CaF2 belongs to the fluoride compounds and has a face-centered cubic (FCC) structure with three sub-lattices. The representative method for CaF2 single crystal growth is Czochralski, which method has the advantages of high production efficiency and the ability to make large crystals. In this study, X-ray diffraction (XRD), X-ray rocking curves (XRC) measurement, and chemical etching were performed to analyze the crystallinity and defect density of the CaF2 single crystals, grown by the Czochralski method. Fourier-transform infrared spectroscopy (FT-IR) and UV-VIS-NIR spectroscopy systems were used to investigate the optical properties of the CaF2 crystal. The provability of various applications, including UV application, was systematically investigated with various analysis results.

Estimation of Spatial Distribution Using the Gaussian Mixture Model with Multivariate Geoscience Data (다변량 지구과학 데이터와 가우시안 혼합 모델을 이용한 공간 분포 추정)

  • Kim, Ho-Rim;Yu, Soonyoung;Yun, Seong-Taek;Kim, Kyoung-Ho;Lee, Goon-Taek;Lee, Jeong-Ho;Heo, Chul-Ho;Ryu, Dong-Woo
    • Economic and Environmental Geology
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    • v.55 no.4
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    • pp.353-366
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    • 2022
  • Spatial estimation of geoscience data (geo-data) is challenging due to spatial heterogeneity, data scarcity, and high dimensionality. A novel spatial estimation method is needed to consider the characteristics of geo-data. In this study, we proposed the application of Gaussian Mixture Model (GMM) among machine learning algorithms with multivariate data for robust spatial predictions. The performance of the proposed approach was tested through soil chemical concentration data from a former smelting area. The concentrations of As and Pb determined by ex-situ ICP-AES were the primary variables to be interpolated, while the other metal concentrations by ICP-AES and all data determined by in-situ portable X-ray fluorescence (PXRF) were used as auxiliary variables in GMM and ordinary cokriging (OCK). Among the multidimensional auxiliary variables, important variables were selected using a variable selection method based on the random forest. The results of GMM with important multivariate auxiliary data decreased the root mean-squared error (RMSE) down to 0.11 for As and 0.33 for Pb and increased the correlations (r) up to 0.31 for As and 0.46 for Pb compared to those from ordinary kriging and OCK using univariate or bivariate data. The use of GMM improved the performance of spatial interpretation of anthropogenic metals in soil. The multivariate spatial approach can be applied to understand complex and heterogeneous geological and geochemical features.

Improved Copper Ion Recovery Efficiency through Surface Modification of Membranes in the Electrodialysis/Solvent Extraction Process (전기투석/용매추출 공정에서 멤브레인 표면 개질을 통한 구리 이온의 회수 효율 향상)

  • Joongwon, Park;Rina, Kim;Hyunju, Lee;Min-seuk, Kim;Hiesang, Sohn
    • Membrane Journal
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    • v.32 no.6
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    • pp.486-495
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    • 2022
  • This study presents the improved recovery efficiency of rare metal ions through the modified separation membrane wettability and hydrogen ion permeation in the anion exchange membrane (AEM) under the recovery process of combined electrodialysis and solvent extraction. Specifically, the wettability of the separator was enhanced by hydrophilic modification on one separator surface through polydopamine (PDA) and lipophilic modification on the other surface through SiO2 or graphene oxide (GO). In addition, the modified surface of AEM with polyethyleneimine (PEI), PDA, poly(vinylidene fluoride) (PVDF), etc. reduces the water uptake and modify the pore structure for proton ions generation. The suppressed transport resulted in the reduced hydrogen ion permeation. In the characterization, the surface morphology, chemical properties and composition of membrane or AEM were analyzed with Scanning Electron Microscopy (SEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). Based on the analyses, improved extraction and stripping and hydrogen ion transport inhibition were demonstrated for the copper ion recovery system.

Development of Real-time Groundwater Quality Monitoring and Advanced Groundwater Purification Technology for Groundwater using Photoinduced Reactive Oxygen Species (지하수 수질 실시간 모니터링 및 광유도 활성산소를 이용한 고도수처리 기술)

  • Kang-Kyun Wang;Byung-Woo Kim
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.15-15
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    • 2023
  • 2020년 기준 국내 상수도 보급률은 99.1% 차지하고 있으며(환경부, 2019), 수도관리차원에서 수돗물은 먹는 물로 시판되어질 만큼 우수한 관리체계를 유지하고 있다. 그 반면에 지하수는 생활용수, 식품가공, 농·축산, 양어, 군부대를 비롯한 전국지역에서 연간 10억 8천만톤 용수를 소비하고 있음에도 (환겨례 신문, 2013; 환경부, 2019) 사용되는 지하수의 약 65%가 음용수 불가판정을 받았으며, 최근 지하수의 오염비율은 급격히 증가하는 추세이다. 특히, 지하수관정의 관리부주의에 의한 수질오염 및 수인성 다제내성균(슈퍼박테리아) 등에 의한 오염사례가 국내는 물론, 국제적으로 다수 보고되고 있는 실정이다 (환경부, 2013). 현재 지하수 수질관리는 공공기관 및 지자체 지정기관을 통해 진행되고 있으며, 검사기간은 수질채취로부터 통상 7~15일정도 소요되어 수질 관리 및 기준, 검사주기에 대한 애로가 많다. 현장 지하수관정에서 실시간 수질을 모니터링하고 이에 연동된 자동 수처리 시스템의 개발 및 도입은 나날이 심각해지는 환경오염 상황에서 선제적 예방과 해결방법으로 중요한 요소기술이다. 현재 지하수오염 및 부적합 음용의 수질처리는 화학약품, 필터여과, UV살균, O3 (플라즈마)을 이용하는 것이 대표적이나, 화학약품의 경우 2차 오염이나 식품 세척 및 가공에 있어 부적합성의 한계점이 있다. 필터여과의 대표적인 RO필터의 경우 약 50% 순손실이 발생하고, UV 살균의 경우 UV에 의한 사용관리자의 위험 및 장비의 광부식 문제, O3 의 경우 고압전류 사용에 따른 위험성 등의 한계점이 나타나고 있다. 지하수 수질정화를 위한 광유도 활성산소(1O2, ·O-2)는 광감응제에 가시광의 빛 조사를 통해 생성되는 활성산소로의 에너지 및 전자 전이가 동시 진행되어 단일항 산소(1O2)와 슈퍼옥사이드 이온(·O-2)을 생성하게 된다. 생성된 활성산소는 유해미생물 또는 유기화학물과 개열, 제거, 치환 반응 등을 통해 미생물사멸 및 유해화학물질들이 분해 가능하다. 이를 이용한 지하수 유해미생물 사멸기술, 장비, 실시간 지하수의 분석기술 및 정수처리, 지하수 물순환 시스템 개발뿐만 아니라 지하수 음용수 및 오염개선, 지하수 기저유출에 의한 오염원 저감으로부터 지류·지천, 하천 본류 수질개선 등의 대상지역에 활용 가능하다. 또한 광유도 활성산소는 기존 상수도 수처리에 있어 오존(O3) 처리와 이산화티탄을 이용한 AOP과정을 단일처리 공정으로, 기존 O3 의 특성상 확산 거리가 매우 길어 사람을 포함한 생체 내에 유입 시 다양한 부작용 발생과 O3 차폐시설 요구의 문제점 극복의 대안으로 환경 및 인체에 무해한 광유도 활성산소 시스템을 적극적으로 도입 및 적용해야 한다. 본 연구 목적은 정류상태 흡광분광기술을 이용한 실시간 수질 모니터링과 광유도 활성산소를 이용한 유해 미생물의 멸균효능 및 지하수 수질관리 기술로의 적용 가능성을 제시하고자 한다.

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