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美国新一代数字电视ATSc 3.0标准技术体系介绍

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广播与电视技术 2015年第A2期40卷 11-19页

作者： Richard chernock Jerry c.whitaker 何大治徐异凌徐洪亮美国高级电视系统委员会上海交通大学未来媒体网络协同创新中心数字电视国家工程研究中心

尽管当前的地面数字电视广播系统（现在被称为ATSc1．0）非常普及，也相当成功，但是，其基础性的构成技术已经使用了20年。技术在不断演进。观众的期望也在日益提升。由于监管和频谱问题，以及提升观众关注度的竞争日益加剧，电视广播... 详细信息

尽管当前的地面数字电视广播系统（现在被称为ATSc1．0）非常普及，也相当成功，但是，其基础性的构成技术已经使用了20年。技术在不断演进。观众的期望也在日益提升。由于监管和频谱问题，以及提升观众关注度的竞争日益加剧，电视广播机构面对的压力越来越大。

关键词：数字电视广播系统标准技术美国广播机构谱问题和频

Hexachlorobutadiene(HcBD)contamination in the Arctic environment:A review

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Emerging contaminants 2019年第1期5卷 116-122页

作者： Jennifer E.Balmer hayley Hung Katrin Vorkamp Robert J.Letcher Derek c.G.Muir Arctic Monitoring and Assessment Programme Fram CentrePO Box 6606 Langnes9296TromsøNorway Department of Biology The Citadel171 Moultrie StreetCharlestonSC29409USA Air Quality Processes Research Section Environment and Climate Change Canada4905 Dufferin StreetTorontoOntarioM3H 5T4Canada Aarhus University Department of Environmental ScienceArctic Research CentreFrederiksborgvej 3994000RoskildeDenmark Ecotoxicology and Wildlife Health Division Environment and Climate Change CanadaNational Wildlife Research CentreCarleton UniversityRaven RoadOttawaOntarioK1A 0H3Canada Environment and climate change canada Canada Centre for Inland Waters867 Lakeshore RoadBurlingtonONL7S 1A1Canada

Hexachlorobutadiene(HcBD)is a halogenated hydrocarbon that is primarily produced as an unintentional byproduct in the manufacture of chlorinated *** between HcBD and other persistent organic pollutants(POPs)led to its listing in 2015 for global regulation under the Stockholm convention on ***'s toxicity and propensity for long-range transport means there is special concern for its potential impacts on Arctic *** present review comprehensively summarizes all available information of the occurrence of HcBD in the Arctic environment,including its atmospheric,terrestrial,freshwater and marine ecosystems and ***,reports of HcBD in Arctic environmental media are *** has been measured in Arctic air collected from monitoring stations in Finland and canada,yet there is a dearth of data for other abiotic matrices(***,sediments,glacier ice,freshwaters and seawater).Low HcBD concentrations have been measured in Arctic terrestrial and marine biota,which is consistent with laboratory studies that indicate that HcBD has the potential to bioaccumulate,but not to *** data for Arctic biota suggest that terrestrial birds and mammals and seabirds,have comparatively higher HcBD concentrations than fish and marine mammals,warranting additional *** spatial and temporal trends in HcBD concentrations in the Arctic are currently limited,future monitoring of HcBD in the Arctic will be important for assessing the impact of global regulations newly-imposed by the Stockholm convention on POPs.

关键词： POPs Air Biota contaminants Long-range transport Review

Sources and environmental fate of pyrogenic polycyclic aromatic hydrocarbons(PAHs)in the Arctic

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Emerging contaminants 2019年第1期5卷 128-142页

作者： Jennifer E.Balmer hayley Hung Yong Yu Robert J.Letcher Derek c.G.Muir Arctic Monitoring and Assessment Programme Fram CentrePO Box 6606 Langnes9296TromsøNorway Department of Biology The Citadel171 Moultrie StreetCharlestonSC29409USA Air Quality Processes Research Section Environment and Climate Change Canada4905 Dufferin StreetTorontoOntarioM3H 5T4Canada Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun130102China Ecotoxicology and Wildlife Health Division Environment and Climate Change CanadaNational Wildlife Research CentreCarleton UniversityRaven RoadOttawaOntarioK1A 0H3Canada Environment and climate change canada Canada Centre for Inland Waters867 Lakeshore RoadBurlingtonONL7S 1A1Canada

Polycyclic aromatic hydrocarbons(PAHs)are large class of hydrophobic,semi-volatile organic contaminants that may enter the environment from both natural sources and anthropogenic *** PAHs arise from the incomplete combustion of fossil fuels and organic matter and following dispersal via long-range transport and may subsequently deposit in surface waters,soils and sediments of remote regions,including the *** current review summarizes and discusses Arctic data that is available for combustion-derived PAHs between 2004 and early 2018,focusing largely on data collected from remote,unexploited Arctic regions and from studies that provide some evidence of a pyrogenic *** increasing use of attribution ratios,which aid in discriminating PAHs from petrogenic or pyrogenic sources,suggest PAHs found in Arctic marine waters and sediment predominantly originate from natural underwater seeps,while those measured in air,freshwater,and terrestrial environments are likely to have originated from atmospheric and combustion-derived *** efforts indicate that atmospheric PAHs in the canadian and Norwegian Arctic are likely to have originated in the northern hemisphere e predominantly from Western Russia,northern Europe,and North *** Asia appears to be a minor source of PAHs to the Arctic,despite contributing more than 50%of global PAH *** comparison to the growing data for atmospheric PAHs,environmental data for these compounds in terrestrial and freshwater environments remain *** have been detected in Arctic biota from terrestrial,freshwater and marine environments,indicating exposure,however,levels are generally low,as most organisms efficiently metabolize parent ***,PAH emissions are expected to decline in the future,however models suggest the Arctic may not experience the same magnitude of decline projected for other world ***,future changes in climate may contribute to a re-volatilizati

关键词： contaminants Air Biota Pyrogenic Petrogenic Review

Sampling duration and freezing temperature influence the analysed gastric inositol phosphate composition of pigs fed diets with different levels of phytase

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Animal Nutrition 2019年第2期5卷 196-201页

作者： Steven Laird Imke Kühn Michael R.Bedford hayley Whitfield Helen M.Miller Faculty of Biological Sciences University of Leeds AB Vista School of Biological Sciences University of East Anglia

This experiment was conducted to determine the effects of time and freezing temperature during sampling on gastric phytate(myo-inositol [MYO] hexakisphosphate [InsP6]), lower inositol phosphates(InsP2-5) and MYO concentrations in pigs fed diets containing different levels of phytase. Forty pigs were fed 1 of 4 wheat-barley diets on an ad libitum basis for 28 d. The diets comprised a nutritionally adequate positive control(Pc), a similar diet but with ca and P reduced by 1.6 and 1.24 g/kg, respectively(Nc), and the Nc supplemented with 500(Nc + 500) or 2,000(Nc + 2000) FTU phytase/kg. At the end of the experiment, chyme were collected from the stomach, thoroughly mixed and 2 subsamples(30 mL) were frozen immediately: one snap-frozen at-79 ℃ and the other at-20 0 c. The remaining chyme were left to sit at room temperature(20 ℃) and further subsamples were collected and frozen as above at 5,10 and15 min from the point of mixing. There were linear reductions in gastric InsP6 concentration over time during sampling(P ctive of diet or freezing temperature. Moreover, InsP6 concentration was influenced by a diet × freezing temperature interaction(P chyme frozen at-20 ℃ than at-79 ℃;however,this difference was greater in the control diets than the phytase supplemented diets. Freezing chyme at-79 ℃ recovered more ∑InsP2-5 + MYO than freezing at-20 ℃ in pigs fed phytase supplemented diets;however, this difference was not apparent in the diets without phytase(diet × freezing temperature, P can be concluded that significant phytate hydrolysis occurs in the gastric chyme of pigs during sampling and processing, irrespective of supplementary phytase activity. Therefore, to minimise post-slaughter phytate degradation and changes in the gastric inositol phosphate profile, chyme should be snap-frozen immediately after collection.

关键词： Pig Inositol phosphate Phytase Sampling time Freezing temperature

Modeling historical budget for β-Hexachlorocyclohexane(HcH)in the Arctic Ocean:A contrast to α-HcH

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Environmental Science and Ecotechnology 2023年第2期14卷 18-28页

作者： Pu-Fei Yang Robie W.Macdonald hayley Hung Derek c.G.Muir Roland Kallenborn Anatoly N.Nikolaev Wan-Li Ma Li-Yan Liu Yi-Fan Li International Joint Research center for Persistent Toxic Substances(IJRc-PTS) State Key Laboratory of Urban Water Resource and EnvironmentSchool of EnvironmentHarbin Institute of TechnologyHarbin150090China International Joint Research center for Arctic Environment and Ecosystem(IJRc-AEE) Polar AcademyHarbin Institute of TechnologyHarbin150090China Institute of Ocean Sciences Department of Fisheries and OceansSidneyBCV8L 4B2Canada centre for Earth Observation Science University of ManitobaWinnipegR3T 2N2Canada Air Quality Processes Research Section Environment and Climate Change CanadaTorontoOntarioCanada canada centre for Inland Waters Environment and Climate Change CanadaBurlingtonOntarioCanada Faculty of chemistry Biotechnology and Food Sciences(KBM)Norwegian University of Life Sciences(NMBU)NOe1433 AsNorway Institute of Natural Sciences North-Eastern Federal UniversityRussia IJRc-PTS-NA TorontoOntarioM2N 6X9Canada

The historical annual loading to,removal from,and cumulative burden in the Arctic Ocean for β-hexachlorocyclohexane(β-HcH),an isomer comprising 5e12%of technical HcH,is investigated using a mass balance box model from 1945 to *** the 76 years,loading occurred predominantly through ocean currents and river inflow(83%)and only a small portion via atmospheric transport(16%).β-HcH started to accumulate in the Arctic Ocean in the late 1940s,reached a peak of 810 t in 1986,and decreased to 87 t in 2020,when its concentrations in the Arctic water and air were~30 ng m^(-3)and~0.02 pg m^(-3),*** though β-HcH and α-HcH(60e70%of technical HcH)are both the isomers of HcHs with almost identical temporal and spatial emission patterns,these two chemicals have shown different major pathways entering the *** from α-HcH with the long-range atmospheric transport(LRAT)as its major transport pathway,β-HcH reached the Arctic mainly through long-range oceanic transport(LROT).The much higher tendency of β-HcH to partition into the water,mainly due to its much lower Henry's Law constant than α-HcH,produced an exceptionally strong pathway divergence with β-HcH favoring slow transport in water and α-HcH favoring rapid transport in *** concentration and burden of β-HcH in the Arctic Ocean are also predicted for the year 2050 when only 4.4-5.3 t will remain in the Arctic Ocean under the influence of climate change.

关键词： β-Hexachlorocyclohexane Arctic Ocean Mass balance model Budget Air-water exchange

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解析贝蒂·弗里丹《女性的奥秘》

A review of chlorinated paraffin contamination in Arctic ecosystems

2020年

作者： Elizabeth whitaker

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Emerging contaminants 2019年第1期5卷 219-231页

作者： Katrin Vorkamp Jennifer Balmer hayley Hung Robert J.Letcher Frank F.Riget Aarhus University Department of Environmental ScienceArctic Research CentreRoskildeDenmark Arctic Monitoring and Assessment Programme TromsøNorway Environment and climate change canada Air Quality Processes Research SectionTorontoCanada Ecotoxicology and Wildlife Health Division Environment and Climate Change CanadaNational Wildlife Research CentreCarleton UniversityOttawaCanada Aarhus University Department of BioscienceArctic Research CentreRoskildeDenmark Greenland Institute of Natural Resources NuukGreenland Present address:The citadel Department of BiologyCharlestonSCUSA

chlorinated paraffins(cPs)present a complex mixture of congeners which are often analysed and assessed as short-,medium-and long-chain cPs,***(c10ec13),SMccP(c14ec17)and SLccP(c18).Their complexity makes the chemical analysis challenging,in particular in terms of accurate quantification,but promising developments involving ultra-high resolution mass spectrometry have been presented *** Arctic data exist for SccPs,while LccPs have not yet been studied in the *** concentrations in Arctic air often exceeded those of SMccP,usually with a predominance of the most volatile c10 congeners,and of banned persistent organic pollutants(POPs),such as polychlorinated biphenyls(PcBs).The presence of SccPs and MccPs in Arctic air,as well as in the Antarctic and in the remote regions of the Tibetan plateau,provides evidence of their long-range transport including sufficient environmental persistence to reach the *** vegetation accumulated SccPs partly from air and partly through root uptake from soil,with consequences for the SccP profile found in Arctic *** results have yet been reported for cPs in terrestrial Arctic *** for freshwater sediment and fish confirmed the long-range transport of SccPs and MccPs and documented their *** additional PcB data were available,SPcB was usually higher than SSccP in freshwater *** SccPs and MccPs were widely present in marine Arctic biota(***,fish,seabirds,seals,whales,polar bears).In mussels and Atlantic cod,SMccP concentrations exceeded those of SSccP,while this was less clear for other marine *** mammals and the long-lived Greenland shark roughly had SSccP concentrations of 100e500 ng/g lipid weight,often dominated by c11 *** appeared to be more pronounced for SSccP than for SMccP,but more studies will be *** SSccP concentrations were observed in Arctic air and sediment over time,but not in beluga monitored since

关键词： Bioaccumulation Biomagnification Long-range transport MccPs Persistent organic pollutants SccPs

Levels and trends of current-use pesticides(cUPs)in the arctic:An updated review,2010-2018

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Emerging contaminants 2019年第1期5卷 70-88页

作者： Jennifer E.Balmer Adam D.Morris hayley Hung Liisa Jantunen Katrin Vorkamp Frank Riget Marlene Evans Magali Houde Derek c.G.Muir Arctic Monitoring and Assessment Programme Fram CentrePO Box 6606Langnes9296TromsøNorway Department of Biology The Citadel171 Moultrie StreetCharlestonSCUSA Environment and climate change canada National Wildlife Research CenterOttawaCanada Air Quality Processes Research Section Environment and Climate Change CanadaTorontoOntarioCanada Air Quality Processes Research Section Environment and Climate Change CanadaEgbertOntarioCanada Aarhus University Department of Environmental ScienceArctic Research CentreRoskildeDenmark Aarhus University Department of BioscienceRoskildeDenmark Aquatic Ecosystem Protection Research Division Environment Canada11 Innovation BlvdSaskatoonSKS7N 3H5Canada Environment and climate change canada St.Lawrence CenterMontrealQuebecCanada Environment and climate change canada Canada Centre for Inland WatersBurlingtonOntarioCanada

Global regulations and many regional and national controls restrict the use of substances that exhibit the potential for environmental persistence and long-range ***,many current-use pesticides(cUPs)continue to be newly discovered in remote regions,including the *** present review serves as an update,summarizing newly available information for cUPs in the Arctic environment and biota published from 2010 to *** 2010,at least seven new cUPs have been measured in Arctic media:2-methyl-4-chlorophenoxyacetic acid(McPA),metribuzin,pendimethalin,phosalone,quizalofop-ethyl,tefluthrin and *** the large number of pesticides in current use,the number measured in the Arctic is very limited,however,modelling studies have identified additional cUPs as potential Arctic contaminants that have yet to be investigated in the *** to their recent detection,reports of cUPs in the Arctic are limited,but *** have been reported in a wide range of abiotic Arctic matrices,including air,snow,ice,freshwater and seawater,indicating their capacity for long-range atmospheric transport,however,concentrations are generally low in comparison to legacy pesticides and other persistent organic pollutants(POPs).Recent food-web studies indicate cUPs can enter Arctic terrestrial and marine food chains,however,in contrast to POPs,the highest concentrations of many cUPs were found in lower trophic-level organisms,and the lowest concentrations detected in animals at the highest trophic levels(i.e,ringed seals,polar bear,caribou,and wolves)indicating significant trophic *** detection of cUPs in the remote Arctic ecosystem reinforces the need for continued monitoring of both known and potential Arctic pollutants to prevent impacts on human and environmental health as the global arsenal of pesticides used in agriculture continuously changes.

关键词： POPs contaminants Air Biota Long-range transport Persistence

Video display engineering

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Video display engineering