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271.
Bruce Swinyard Peter Clegg Sarah Leeks Matt Griffin Tanya Lim Martin Burgdorf 《Experimental Astronomy》2000,10(2-3):157-176
The performance of the ten doped germaniumphotoconducting detectors on the Infrared SpaceObservatory Long Wavelength Spectrometer is discussed. This instrument was designed to make spectroscopicmeasurements of astronomical sources in the wavelengthrange from 43 to 198 m. It employed* a combination of stressed and unstressed Ge:Ga detectorsand one Ge:Be detector coupled to Infrared Labs JF-4integrating amplifiers. The performance of thedetectors was affected by the ionising radiation inthe space environment. The Noise Equivalent Power ofthe detectors increased by a factor of 4 compared tothat measured during ground testing. We show thatthis was the result of reducing the operating bias,and therefore the responsivity, of the detectors andusing shorter integration ramps to alleviate theeffects of the ionising radiation impacts.
ast ISO exhausted its helium supply on 8 April 1998. 相似文献
272.
Choi Seonghu Choi Man-Sik Joe Dongjin Park Sojung Kim Jinwoo Ra Kongtae Kim Intae Kim Kyung-Tae Lee Kyoung-Seok Lim Jean-Sun 《Ocean Science Journal》2022,57(3):436-450
Ocean Science Journal - The spatial distributions of dissolved lead (Pb) concentrations and stable Pb isotope ratios in the Ulleung Basin, East/Japan Sea, were investigated to identify the Pb... 相似文献
273.
Hyung-Gyu Lim Sang-Wook Yeh Ji-Won Kim Rokjin Park Chang-Keun Song 《Meteorology and Atmospheric Physics》2014,126(1-2):71-79
Due to the dramatic increase in the global mean surface temperature (GMST) during the twentieth century, the climate science community has endeavored to determine which mechanisms are responsible for global warming. By analyzing a millennium simulation (the period of 1000–1990 ad) of a global climate model and global climate proxy network dataset, we estimate the contribution of solar and greenhouse gas forcings on the increase in GMST during the present warm period (1891–1990 ad). Linear regression analysis reveals that both solar and greenhouse gas forcing considerably explain the increase in global mean temperature during the present warm period, respectively, in the global climate model. Using the global climate proxy network dataset, on the other hand, statistical approach suggests that the contribution of greenhouse gas forcing is slightly larger than that of solar forcing to the increase in global mean temperature during the present warm period. Overall, our result indicates that the solar forcing as well as the anthropogenic greenhouse gas forcing plays an important role to increase the global mean temperature during the present warm period. 相似文献
274.
For the determination of benthic community health criteria of a biotic index, Benthic Pollution Index (BPI), the faunal data on macrobenthic community of Deukryang Bay collected in 2012 were used. Each macrobenthic fauna was classified into 4 functional groups according to their feeding and life history strategies and BPI was calculated using the abundance of fauna for these functional groups. Amphipods were the dominant faunal group belonging to Functional Group (FG) II in Deukryang Bay during all seasons. The BPI value fluctuated seasonally from 55 to 61, and the overall mean value of BPI in the reference area was 60, which was estimated as the threshold value for healthy communities. We tried to use BPI as an assessment tool for macrofaunal community health status by categorizing the BPI values into 5 grades. If the BPI value of the community is more than 60, the health status of a macrobenthic community will be assessed as ‘Excellent’ (Grade 1) and as ‘Good’ (Grade 2), if between 40 and 60, as ‘Fair’ (Grade 3), if between 30 and 40, as ‘Poor’ (Grade 4), if between 20 and 30, and finally the health status of a community will be assessed as ‘Very Poor’ (Grade 5), if the BPI value is less than 20. This assessment tool using BPI was applied to macrobenthic communities in Jinhae Bay including the Special Management Area of South Korea. In Jinhae Bay, the FG IV containing a spionid species, Paraprionospio patiens was the most dominant group. The values of BPI in Jinhae Bay were very low and ranged from 11 to 23. The ecological health status of macrobenthic communities in Jinhae Bay was ‘Very Poor’ at more than 50% of sites, especially in summer. 相似文献
275.
Macrobenthic fauna were collected seasonally at 44 sites in Deukryang Bay from February to November, 2012. The species number of macrobenthic fauna was in the range of 140 to 181, and polychaetes comprised 41.4% of them. The average density of the whole study area changed seasonally from 755 to 1,507 ind. m?2, and the most abundant fauna group was crustaceans which accounted for 55.1% of total abundance. An amphipod species Nippopisella nagatai was the most dominant species and a decapod species Xenophthalmus pinnotheroides, an amphipod species Photis longicaudata, and a polychaete species Paralacydonia paradoxa were also dominant in all seasons. The mean seasonal values of Shannon’s diversity index (H′) were in the range of 2.2–2.4, and those values for the evenness index and richness index were 0.7–0.7 and 4.6–5.7, respectively. From the cluster analysis, Deukryang Bay could be divided into 3 or 4 station groups with its specific fauna composition. The cluster analysis and an nMDS ordination revealed that local environmental factors such as water depth were related to the spatial delineation of macrobenthic fauna communities in Deukryang Bay. 相似文献
276.
277.
Kwon Yong Min Bae Seung Sub Choi Grace Lim Ji Yeon Jung Yoon-Hee Chung Dawoon 《Ocean Science Journal》2021,56(1):1-17
Ocean Science Journal - Studies on marine fungi (termed as ‘marine-derived fungi’ in this paper) have been significantly increasing worldwide because of the critical role displayed by... 相似文献
278.
Atmospheric wet deposition of PAHs to the sea-surface microlayer 总被引:1,自引:1,他引:0
Sea-surface microlayer (SML) and subsurface seawater samples (SSW) collected from Singapore's coastal environment were analyzed for 14 polycyclic aromatic hydrocarbons (PAHs) in the dissolved (DP) and suspended particulate phase (SPM). Samples were collected prior to and after rainfall events to ascertain the contribution of wet atmospheric deposition of PAH enrichment to the SML. The concentration ranges of summation operatorPAHs in the SML before rain and after wet deposition were 2.6-46.2 ngL(-1) and 4.3-278.0 ngL(-1), respectively, for the DP and 3.8-31.4 ngL(-1) and 12.8-1280 ngL(-1), respectively, for the SPM. Load factors (i.e. concentration after wet deposition relative to before wet deposition) of the atmospheric wet deposition for DP and SPM ranged from 1.4 to 42.9 and 1.2 to 337, respectively. This study provides the first data on PAH concentration, enrichment (i.e. concentration of PAHs in SML relative to subsurface water) and load factors in the SML before and after wet deposition to the ocean surface. 相似文献
279.
Beth Ellen Clark Richard P. Binzel Ellen S. Howell Edward A. Cloutis Maureen Ockert-Bell Phil Christensen Maria Antonietta Barucci Francesca DeMeo Dante S. Lauretta Harold Connolly Jr. Alicia Soderberg Carl Hergenrother Lucy Lim Josh Emery Michael Mueller 《Icarus》2011,216(2):462-475
We present reflectance spectra from 0.4 to 2.4 μm of Asteroid (101955) 1999 RQ36, the target of the OSIRIS-REx spacecraft mission. The visible spectral data were obtained at the McDonald Observatory 2.1-m telescope with the ES2 spectrograph. The infrared spectral data were obtained at the NASA Infrared Telescope Facility using the SpeX instrument. The average visible spectrum is combined with the average near-infrared wavelength spectrum to form a composite spectrum. We use three methods to constrain the compositional information in the composite spectrum of Asteroid (101955) 1999 RQ36 (hereafter RQ36). First, we perform a least-squares search for meteorite spectral analogs using 15,000 spectra from the RELAB database. Three most likely meteorite analogs are proposed based on the least-squares search. Next, six spectral parameters are measured for RQ36 and their values are compared with the ranges in parameter values of the carbonaceous chondrite meteorite classes. A most likely meteorite analog group is proposed based on the depth of overlap in parameter values. The results of the least-squares search and the parametric comparisons point to CIs and/or CMs as the most likely meteorite analogs for RQ36, and COs and CHs as the least likely. RQ36 has a spectrally “blue” continuum slope that is also observed in carbonaceous chondrites containing magnetite. We speculate that RQ36 is composed of a “CM1”-like material. Finally, we compare RQ36 to other B-type asteroids measured by Clark et al. (Clark, B.E. et al. [2010]. J. Geophys. Res. 115, E06005). The results of this comparison are inconclusive. RQ36 is comparable to Themis spectral properties in terms of its albedo, visible spectrum, and near-infrared spectrum from 1.1 to 1.45 μm. However, RQ36 is more similar to Pallas in terms of its near-infrared spectrum from 1.6 to 2.3 μm. Thus it is possible that B-type asteroids form a spectral continuum and that RQ36 is a transitional object, spectrally intermediate between the two end-members. This is particularly interesting because Asteroid 24 Themis was recently discovered to have H2O ice on the surface (Rivkin, A., Emery, J. [2010]. Nature 464, 1322–1323; Campins, H. et al. [2010a]. Nature 464, 1320–1321). 相似文献
280.
An examination was carried out of the encrusting materials on the seepage removal pumps in a bottom sump of an undersea liquefied petroleum gas (LPG) cavern. The studied cavern, constructed at 8 km off the western coast of Korea, facing the Yellow Sea, is at 130–150 m below the seabed. Since the first filling of the LPG into the cavern, it has suffered from the unexpected problem of a thick encrustation of unknown materials on the seepage removal pumps of the cavern. The XRD and XRF analyses revealed that the encrustation materials were mainly iron (hydro)oxides and carbonate mineral (aragonite). Based on the geological setting below the cavern site, it was inferred that iron oxides found in the Pleistocene sandy sediment and the Precambrian gneiss might be supplying ferrous iron to the cavern waters under an anaerobic condition, evidenced by low dissolved oxygen and negative redox potential in the cavern water. A significant change in the hydraulic condition near the pump intake and mixing the cavern water with oxic waters supplied through re-circulated seawater and terrestrial groundwater discharge, would precipitate the dissolved iron. Precipitation of the carbonate mineral is thought to have occurred due to over-saturation of calcium and bicarbonate, which may have resulted from the dissolution of cement grouting materials used during the undersea cavern construction and submarine groundwater discharge (SGD). This study reports the iron and carbonate precipitation in the man-made undersea cavern, which is affected by the surrounding hydrogeological condition and the SGD. 相似文献