• Title/Summary/Keyword: in situ observations

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Case Study of High-speed Real-time Plasma Arc Detection (실시간 고속 플라즈마 아킹 검출에 대한 연구)

  • Hong, Sang-Jin
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.11a
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    • pp.183-183
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    • 2015
  • Arc in plasma processing chamber results in high current discharge marks and particles on wafers, but it is hard to identify or observe it during the proc ess. In this paper, we report the observations of plasma arc s during various plasma proc esses through a non-invasive optic al plasma monitoring system (OPMS) devised for the in-situ detec tion of abnormal discharge.

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Long-term and multidisciplinary research networks on biodiversity and terrestrial ecosystems: findings and insights from Takayama super-site, central Japan

  • Hiroyuki Muraoka;Taku M. Saitoh;Shohei Murayama
    • Journal of Ecology and Environment
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    • v.47 no.4
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    • pp.228-240
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    • 2023
  • Growing complexity in ecosystem structure and functions, under impacts of climate and land-use changes, requires interdisciplinary understandings of processes and the whole-system, and accurate estimates of the changing functions. In the last three decades, observation networks for biodiversity, ecosystems, and ecosystem functions under climate change, have been developed by interested scientists, research institutions and universities. In this paper we will review (1) the development and on-going activities of those observation networks, (2) some outcomes from forest carbon cycle studies at our super-site "Takayama site" in Japan, and (3) a few ideas how we connect in-situ and satellite observations as well as fill observation gaps in the Asia-Oceania region. There have been many intensive research and networking efforts to promote investigations for ecosystem change and functions (e.g., Long-Term Ecological Research Network), measurements of greenhouse gas, heat, and water fluxes (flux network), and biodiversity from genetic to ecosystem level (Biodiversity Observation Network). Combining those in-situ field research data with modeling analysis and satellite remote sensing allows the research communities to up-scale spatially from local to global, and temporally from the past to future. These observation networks oftern use different methodologies and target different scientific disciplines. However growing needs for comprehensive observations to understand the response of biodiversity and ecosystem functions to climate and societal changes at local, national, regional, and global scales are providing opportunities and expectations to network these networks. Among the challenges to produce and share integrated knowledge on climate, ecosystem functions and biodiversity, filling scale-gaps in space and time among the phenomena is crucial. To showcase such efforts, interdisciplinary research at 'Takayama super-site' was reviewed by focusing on studies on forest carbon cycle and phenology. A key approach to respond to multidisciplinary questions is to integrate in-situ field research, ecosystem modeling, and satellite remote sensing by developing cross-scale methodologies at long-term observation field sites called "super-sites". The research approach at 'Takayama site' in Japan showcases this response to the needs of multidisciplinary questions and further development of terrestrial ecosystem research to address environmental change issues from local to national, regional and global scales.

Histopathological observations and virus detection by in situ hybridization in wild rats intranasally infected with Aujeszky's disease virus isolated in Korea (국내분리 오제스키병 바이러스로 비강접종한 야생집쥐(Rattus norvegicus)의 병리학적 소견 및 in situ hybridization에 의한 바이러스 동정)

  • Song, Geun-seok;Moon, Oun-kyong;Jeong, Chang-geun;Kim, Soon-bok
    • Korean Journal of Veterinary Research
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    • v.39 no.3
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    • pp.531-537
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    • 1999
  • The present study was carried out to investigate the pathogenicity and pathogenesis of wild rats(Rattus norvegicus), trapped in nature, intranasally infected with Aujeszky's disease virus(ADV/NYJ-1-87) by histopathology, immunohistochemistry and in situ hybridization(ISH). Fifteen rats inoculated intranasally were roughened haircoat, anorexia, listlessness, and depression second day after inoculation, and three rats died in 66-72 hours. Eight rats showed severe pruritus at the face that was accompanied by frequent face-washing movements of the forelegs, and then became violent and spasmodic for an hour or until they died. Four rats slowly recovered after showing mild clinical signs of the disease. Microscopic lesions in infected rats were characterized by meningitis, perivascular round cell infiltration, focal gliosis, and neuronal degeneration and necrosis. And intranuclear inclusion bodies were frequently detected in the cerebral cortex and medulla. Positive reaction to ADV by immunohistochemistry and ISH were detected in the following areas : trigermimal ganglion, brain, tonsil, nasal mucosa, spleen, lung and liver. The result has suggested that ADV intranasally infected in wild rats is followed by replication in epithelial calls of nasal mucosa and tonsil, then invade local lymph nodes by way of the lymphatics. It is also believed that the virus invades bipolar olfactory cells and trigerminal ganglion; and then spread into central nervous system.

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Understanding Deactivation of Ru Catalysts by In-situ Investigation of Surface Oxide Stability under CO Oxidation and Oxidative/Reductive Conditions

  • Qadir, Kamran;Joo, Sang-Hoon;Mun, Bong-Jin S.;Park, Jeong-Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.212-212
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    • 2011
  • In addition to the catalysts' activity and selectivity, the deactivation of catalysts during use is of practical importance. It is crucial to understand the phenomena of the deactivation to predict the loss of activity during catalyst usage so that the high operational costs associated with catalyst replacement can be reduced. In this study, the activity of Ru catalysts, such as nanoparticles (3~6 nm) and polycrystalline thin film (50 nm), have been investigated under CO oxidation and oxidative/reductive reaction conditions at various temperatures with the ambient pressure X-Ray photoelectron spectroscopy (APXPS). With APXPS, the surface oxides on the catalyst are measured and monitored in-situ. It was found that the Ru film exhibited faster oxidation-and-reduction compared to that of nanoparticles showing mild oxidative-and-reductive characteristics. Additionally, the larger Ru nanoparticles showed a higher degree of oxide formation at all temperatures, suggesting a higher stability of the oxide. These observations are in agreement with the catalytic activity of Ru catalysts. The loss of activity of Ru films is correlated with bulk oxide formation, which is inactive in CO oxidation. The Ru nanoparticle, however, does not exhibit deactivation under similar conditions, suggesting that its surface is covered with a highly active ultrathin surface oxide. Since the active oxide is more stable as nanoparticles than as a film, the nanoparticles showed mild oxidative/reductive behavior, as confirmed by APXPS results. We believe these simultaneous observations of both the surface oxide of Ru catalysts and the reactivity in real time enable us to pinpoint the deactivation phenomena more precisely and help in designing more efficient and stable catalytic systems.

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In-situ Phase Transition Study of Minerals using Micro-focusing Rotating-anode X-ray and 2-Dimensional Area Detector (집속 회전형 X-선원과 이차원 검출기를 이용한 광물의 실시간 상전이 연구)

  • Seoung, Dong-Hoon;Lee, Yong-Moon;Lee, Yong-Jae
    • Economic and Environmental Geology
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    • v.45 no.2
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    • pp.79-88
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    • 2012
  • The increased brightness and focused X-ray beams now available from laboratory X-ray sources facilitates a variety of powder diffraction experiments not practical using conventional in-house sources. Furthermore, the increased availability of 2-dimensional area detectors, along with implementation of improved software and customized sample environmental cells, makes possible new classes of in-situ and time-resolved diffraction experiments. These include phase transitions under variable pressure- and temperature conditions and ion-exchange reactions. Examples of in-situ and time-resolved studies which are presented here include: (1) time-resolved data to evaluate the kinetics and mechanism of ion exchange in mineral natrolite; (2) in-situ dehydration and thermal expansion behaviors of ion-exchanged natrolite; and (3) observations of the phases forming under controlled hydrostatic pressure conditions in ion-exchanged natrolite. Both the quantity and quality of the in-situ diffraction data are such to allow evaluation of the reaction pathway and Rietveld analysis on selected dataset. These laboratory-based in-situ studies will increase the predictability of the follow-up experiments at more specialized beamlines at the synchrotron.

Microfracture Mechanism of Squeeze Cast AZ51-xSn Magnesium Alloys (용탕단조법으로 제조된 AZ51-xSn 마그네슘 합금의 미세파괴기구)

  • Kim, Byeong Ho;Do, Jeonghyeon;Lee, Sunghak;Park, Ikmin
    • Korean Journal of Metals and Materials
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    • v.47 no.12
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    • pp.797-810
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    • 2009
  • A study was made of the effects of a Sn addition on the microstructure and microfracture mechanism of squeeze cast AZ51-xSn magnesium alloys. Microstructural observation, in situ fracture testing, and fractographic observations were conducted on these alloys to clarify the microfracture process. The microstructural analyses indicated that $Mg_2Sn$ particles as well as $Mg_{17}Al_{12}$ particles precipitated mainly along the solidification cell boundaries; the volume fraction of these hard particles increased as the amount of added Sn increased, with increased the strength. From in situ fracture observations of the AZ51-7Sn alloy, coarse precipitates located on the cell boundaries worked as easy crack propagation sites and caused abrupt intercellular fracturing. On the other hand, the overall fracture properties of the AZ51-3Sn alloy improved because crack propagation proceeded into the Mg matrix rather than into the cell boundaries as twins developed actively, as confirmed by an R-curve analysis. These findings suggest that the addition of 3~5 wt.% Sn is effective in improving both the tensile and fracture properties on the basis of well-developed twins, the blocking of crack propagation, and crack blunting.

Monitoring and spatio-temporal analysis of UHI effect for Mansa district of Punjab, India

  • Kaur, Rajveer;Pandey, Puneeta
    • Advances in environmental research
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    • v.9 no.1
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    • pp.19-39
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    • 2020
  • Urban heat island (UHI) is one of the most important climatic implications of urbanization and thus a matter of key concern for environmentalists of the world in the twenty-first century. The relationship between climate and urbanization has been better understood with the introduction of thermal remote sensing. So, this study is an attempt to understand the influence of urbanization on local temperature for a small developing city. The study focuses on the investigation of intensity of atmospheric and surface urban heat island for a small urbanizing district of Punjab, India. Landsat 8 OLI/TIRS satellite data and field observations were used to examine the spatial pattern of surface and atmospheric UHI effect respectively, for the month of April, 2018. The satellite data has been used to cover the larger geographical area while field observations were taken for simultaneous and daily temperature measurements for different land use types. The significant influence of land use/land cover (LULC) patterns on UHI effect was analyzed using normalized built-up and vegetation indices (NDBI, NDVI) that were derived from remote sensing satellite data. The statistical analysis carried out for land surface temperature (LST) and LULC indicators displayed negative correlation for LST and NDVI while NDBI and LST exhibited positive correlation depicting attenuation in UHI effect by abundant vegetation. The comparison of remote sensing and in-situ observations were also carried out in the study. The research concluded in finding both nocturnal and daytime UHI effect based on diurnal air temperature observations. The study recommends the urgent need to explore and impose effective UHI mitigation measures for the sustainable urban growth.

Characteristics of Water Temperature Inversion Observed in a Region West of Jeju Island in April 2015 (2015년 4월에 제주 서부해역에서 발생한 수온역전층 특성)

  • Kim, Seong Hyeon
    • Ocean and Polar Research
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    • v.42 no.2
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    • pp.97-113
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    • 2020
  • In-situ observations were carried out in April 2015 to investigate the occurrence of water temperature inversion in a region west of Jeju Island. Analysis of in-situ in the western part of Jeju island showed that cold water moved to the southeast from the surface to the middle layer and warm water moved from the middle to the lower layer of the northwest direction. The water temperature inversion occurred at 84 stations (63.1%) out of 133 stations. At the boundary of the water temperature inversion layer, it was formed in the middle layer and disappeared. In the strongly appearing, it started from the middle layer to the lower layer. The shape of the water temperature inversion layer was different. As a result of horizontal water temperature slope analysis of the water temperature inversion zone, maximum 0.23℃/km was obtained and the mean was 0.06℃/km. The role of water temperature inversion as an indicator to determine the formation of water front. As a result of the water mass analysis, Jeju Warm Current Water and Tsushima Warm Current Water of high temperature and high salt intruded from the middle to the bottom. In the middle layer occurred as the Yellow Sea Cold Water of low water temperature and low salinity expanded.

Spatio-Temporal Variation of Cold Water Masses along the Eastern Coast of Korea in 2013 and 2014

  • Han, In-Seong;Park, Myung-Hee;Min, Seung-Hwan;Kim, Ju-Yeon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.3
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    • pp.286-295
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    • 2016
  • With the results of observations in 2013 and 2014 including ocean buoys, in-situ investigations and wind data, we examined the spatio-temporal variation of cold water masses along the eastern coast of Korea. Usually, a cold water mass first appears along the northern part of the eastern coast from May to July, and then along the southern part of the eastern coast from late June to mid-August. Cold water masses appear 3~5 times a year and remain for 5~20 days in the southwestern part of the East Sea. A distinctive cold water mass appeared usually in mid-July in this area, the surface temperature of which was below $10^{\circ}C$ in some cases. During the appearance of a cold water mass in the southwestern part of the East Sea, the horizontal temperature gradient was large at the surface and a significant low water temperature below $8^{\circ}C$ appeared at the bottom level. This appearance of cold water masses clearly corresponded to southwesterly winds, which generated coastal upwelling.

Quantification of Bacillus Species in a Wastewater Treatment System by the Molecular Analyses

  • Mori Koji;Iriye Ryozo;Hirata Mutsunori;Takamizawa Kazuhiro
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.9 no.6
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    • pp.482-489
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    • 2004
  • Bacillus species were observed and quantified by molecular approaches, using the 16S rDNA primers/probes, in a wastewater treatment plant designed for the purpose of stimulating the growth of Bacillus species. The plant has been operating as a test plant since 1997 in the city of Ina, Japan, with excellent treatment performance. Observations by in situ hybridization, using Bacillus-specific probes, indicated that Bacillus strains were inhabited in the plant and their num­bers decreased during the treatment process. Similar results were obtained from a quantitative PCR analysis using a Bacillus-specific primer set, and the amount of DNA originating from various Bacillus species was maximally $1.91%\$ of the total DNA in the wastewater treatment tank. Clone library analysis using the Bacillus-specific primers suggested that, while the population was no­ticeably increased, the phylogenetic diversity of the increasing Bacillus species was very low.