Sample preparation for analyzing polycyclic aromatic hydrocarbons and polychlorinated dibenzo-p-dioxins and dibenzofurans in sediment by gas chromatography/mass spectrometry     

Yulin L. Tan  Ada Kong  Yue-on Chiu 《Estuaries and Coasts》1993,16(3):427-432

A sample preparation technique was developed to isolate and separate two classes of combustion-produced pollutants: three- to six-ring polycyclic aromatic hydrocarbons (PAH) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), from sediment samples for interference-free analyses by gas chromatography/mass spectrometry (GC/MS). The method involves soxhlet extraction with methylene chloride, sulfur removal with activated copper powder, gel filtration chromatography with Sephadex LH-20, polarity separations of PAH and PCDD/F with prepacked silica gel solid-phase extraction columns, and isolation of PCDD/F from polychlorinated biphenyls with microalumina columns. Stringent procedural controls were established to achieve clean isolations and recoveries of 70% or better for each step in the method. The prepared sample extracts were analyzed by capillary GC and GC/MS. Electron impact ionization was used for PAH, and negative chemical ionization with methane as a reagent gas was used for PCDD/F. Reproducible results were obtained. The method is simple and has the advantage of conserving sample consumption since two classes of compounds can be analyzed from the same sample. This can be critical in sediment core analyses where sample size is usually limited.  相似文献   

A preliminary study of crustal structure in Taiwan region using receiver function analysis   总被引：2，自引：0，他引：2  

Kwang-Hee Kim  Jer-Ming Chiu  Honn Kao  Qiyuan Liu  Yih-Hsiung Yeh 《Geophysical Journal International》2004,159(1):146-164

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Comparison of TRMM and water district rain rates over New Mexico   总被引：10，自引：0，他引：10  

Long S. CHIU  Zhong LIU  Jearanai VONGSAARD  Stanley MORAIN  Amy BUDGE  Paul NEVILLE  Chandra BALES 《大气科学进展》2006,23(1):1-13

This paper compares monthly and seasonal rain rates derived from the Version 5 (V5) and Version 6 (V6) TRMM Precipitation Radar (TPR, TSDIS reference 2A25), TRMM Microwave Imager (TMI, 2A12), TRMM Combined Instrument (TCI, 2B31), TRMM calibrated IR rain estimates (3B42) and TRMM merged gauge and satellite analysis (3B43) algorithms over New Mexico (NM) with rain gauge analyses provided by the New Mexico water districts (WD). The average rain rates over the NM region for 1998–2002 are 0.91mmd?1 for WD and 0.75, 1.38, 1.49, 1.27, and 1.07mmd?1 for V5 3B43, 3B42, TMI, PR and TCA; and 0.74, 1.38, 0.87 and 0.97 mm d?1 for V6 3B43, TMI, TPR and TCA, respectively. Comparison of V5 3B43 with WD rain rates and the daily TRMM mission index (TPR and TMI) suggests that the low bias of V5 3B43 for the wet months (summer to early fall) may be due to the non-inclusion of some rain events in the operational gauge analyses that are used in the production of V5 3B43. Correlation analyses show that the WD rain rates vary in phase, with higher correlation between neighboring WDs. High temporal correlations (>0.8) exist between WD and the combined algorithms (3B42, 3B43 and TCA for both V5 and V6) while satellite instrument algorithms (PR, TMI and TCI) are correlated best among themselves at the monthly scale. Paired t-tests of the monthly time series show that V5 3B42 and TMI are statistically different from the WD rain rates while no significant difference exists between WD and the other products. The agreements between the TRMM satellite and WD gauge estimates are best for the spring and fall and worst for winter and summer. The reduction in V6 TMI (?7.4%) and TPR (?31%) rain rates (compared to V5) results in better agreement between WD estimates and TMI in winter and TPR during summer.  相似文献   

Navigating ethnicity: segregation,placemaking, and difference     

Francesca Chiu 《Urban geography》2019,40(4):582-583

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Marine 3D seismic volumes from 2D seismic survey with large streamer feathering     

Lin  Liang-Fu  Hsu  Ho-Han  Liu  Char-Shine  Chao  Kuo-Han  Ko  Chia-Chun  Chiu  Shye-Dong  Hsieh  Hsin-Sung  Ma  Yu-Fang  Chen  Song-Chuen 《Marine Geophysical Researches》2019,40(4):619-633

Marine Geophysical Research - Strong ocean current influences a marine seismic survey and forces the streamer off-course from the survey line. The sideway drift of the streamer results in that the...  相似文献   

A multimetric-index approach using fisheries data to assess fish assemblage structure in relation to salinity gradient in a tropical West African estuary     

J Kantoussan  JM Ecoutin  R Laë  OT Thiaw  L Tito de Morais 《African Journal of Marine Science》2018,40(2):175-185

This study examines the effects of increasing salinity on fish assemblage structure in the Casamance Estuary, Senegal, using a series of indices. The study data were derived from commercial fishery surveys conducted between April and July 2005. Analysis of within-trophic-group diversity in the Casamance Estuary shows a significant drop in the diversity of apex predators in the upper, more saline reaches of the estuary. By contrast, primary consumers adapted well to salinity changes and exhibited higher taxonomic diversity in the upper reaches of the estuary than in the lower reaches. The findings also indicate decreases in average sizes of the landed species and the trophic levels among fish catches in the direction of the upper reaches. However, the catch per unit effort (CPUE) was globally higher in the upstream area of the estuary as compared with the downstream area. This increasing CPUE trend from the lower towards the upper reaches is attributed to (i) the high primary productivity in the upper Casamance Estuary; (ii) the increasing abundance of euryhaline fish species in an upstream direction; and (iii) ‘telescoping’ of the food chain through the presence of mostly herbivorous fishes in the upper reaches. Such a situation likely facilitated high fish production in the upstream area of the estuary, though multimetric indices indicated unfavourable living conditions for many fish taxa in this area.  相似文献   

Classification of marine bioregions on the east coast of South Africa     

T-C Livingstone  JM Harris  AT Lombard  AJ Smit  DS Schoeman 《African Journal of Marine Science》2018,40(1):51-65

Marine bioregional planning requires a meaningful classification and spatial delineation of the ocean environment using biological and physical characteristics. The relative inaccessibility of much of the ocean and the paucity of directly measured data spanning entire planning regions mean that surrogate data, such as satellite imagery, are frequently used to develop spatial classifications. However, due to a lack of appropriate biological data, these classifications often rely on abiotic variables, which act as surrogates for biodiversity. The aim of this study was to produce a fine-scale bioregional classification, using multivariate clustering, for the inshore and offshore marine environment off the east coast of South Africa, adjacent to the province of KwaZulu-Natal and out to the boundary of the exclusive economic zone (EEZ), 200 nautical miles offshore. We used remotely sensed data of sea surface temperature, chlorophyll a and turbidity, together with interpolated bathymetry and continental-slope data, as well as additional inshore data on sediments, seabed oxygen and bottom temperature. A multivariate k-means analysis was used to produce a fine-scale marine bioregionalisation, with three bioregions subdivided into 12 biozones. The offshore classification was primarily a pelagic bioregionalisation, whereas the inshore classification (on the continental shelf) was a coupled benthopelagic bioregionalisation, owing to the availability of benthic data for this area. The resulting classification was used as a base layer for a systematic conservation plan developed for the province, and provided the methods for subsequent planning conducted for the entire South African EEZ. Validation of the classification is currently being conducted in marine research programmes that are sampling benthic biota and habitats in a sampling design stratified according to the biozones delineated in this study.  相似文献   

Internal solitons in the northeastern south China Sea. Part I: sources and deep water propagation   总被引：11，自引：0，他引：11  

Ramp  S.R. Tswen Yung Tang Duda  T.F. Lynch  J.F. Liu  A.K. Ching-Sang Chiu Bahr  F.L. Hyoung-Rok Kim Yang  Y.-J. 《Oceanic Engineering, IEEE Journal of》2004,29(4):1157-1181

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A very cool brown dwarf in UKIDSS DR1     

S. J. Warren  D. J. Mortlock  S. K. Leggett  D. J. Pinfield  D. Homeier  S. Dye  R. F. Jameson  N. Lodieu  P. W. Lucas  A. J. Adamson  F. Allard  D. Barrado y Navascués  M. Casali  K. Chiu  N. C. Hambly  P. C. Hewett  P. Hirst  M. J. Irwin  A. Lawrence  M. C. Liu †  E. L. Martín  R. L. Smart  L. Valdivielso  B. P. Venemans 《Monthly notices of the Royal Astronomical Society》2007,381(4):1400-1412

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Erratum     

Liang-Tai George Chiu 《Celestial Mechanics and Dynamical Astronomy》1981,24(2):227-227

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