泥蚶及菲律宾蛤仔对环境中氨的耐受力   总被引：1，自引：0，他引：1  

汪心沅 《海洋科学》1989,13(6):51-54

本文对泥蚶成贝、幼贝,菲律宾蛤仔成贝、幼贝的未离解氨氮 168h LCD_(50),EC_(50)(降低耐低氧环境能力50%的浓度)进行了试验,并对氨的致死和亚致死浓度与内湾养虾水域(乳山东湾)、试验虾池及利用虾池水的试验贝池底质环境的氨氮水平作了概略评价。  相似文献   

Characteristics and Environmental Significance of pH and EC in Summer Rainfall and Shallow Firn Profile at Yulong Snow Mountain,Lijiang City,China     

李宗省  何元庆  Wilfred H Theakstone  贾文雄  辛惠娟  张蔚  刘婧  王淑新 《中国地质大学学报(英文版)》2010,(2)

The seasonal and inter-annual variations of pH and EC(electrical conductivity) at Yu-long(玉龙) Snow Mountain,Lijiang(丽江) City,are sensitive to precipitation variations and are important indicators of the atmospheric environment.The pH of summer rainfall at Lijiang City ranges from 6.7 to 7.4,and alkaline mineral salts dominate the variations of rainfall acidity.pH values in theshallow firn profile at Baishui(白水) Glacier No.1 range from 5.6 to 6.3,and EC values from 2.4 to 7.3 μs/cm.The ranges are lower than ...  相似文献   

Bestimmung polarer Phosphorsäureester in Trink‐ und Oberflächenwasser mittels HPLC‐MS‐MS     

Michaela Ventker  Friedrich Werres  Peter Balsaa  Peter Winterhalter  Horst Overath 《洁净——土壤、空气、水》2004,32(1):40-47

Determination of Organophosphorus Pesticides in Water by HPLC‐MS‐MS In the EC Water Framework Directive 2000/60/EG and in CEC 76/464/EEC there are 16 organophosphorus pesticides (insecticides and acaricides) listed which belong to so‐called priority substances. The committed quality aims of these substances frequently require maximum concentrations below 0.1 μg/L. In this paper a HPLC‐MS‐method is described. The reported limits of determination of organophosphorus pesticides are lower than the demanded limits. High analytical sensitivity is reached by solid‐phase extraction (SPE) and by injecting large volumes. For some of these substances no sample enrichment is needed and low detection limits are obtained by direct injection of the original water sample.  相似文献   

Linkage of liquid conductivity of glacier ice with its alkalinity over the north Qinghai-Xizang (Tibet) Plateau     

Cunde Xiao  Tandong Yao  Dahe Qin  Seko Katsumoto  Jianchen Pu  Wenkun Sheng 《中国科学D辑(英文版)》2002,45(4):300-310

Liquid conductivity (EC) measurement was conducted for the samples collected from several snow pits and ice cores over the Qinghai-Xizang (Tibet) Plateau, with their time range covering seasonal, decadal and centennial scales. Unlike the previous attention mostly focused on the acidity (H⁺) responding to the solid conductance (ECM) of glacial ice, we introduce the alkalinity (OH⁻) of snow and ice to show how it responds to EC. Strong linear relationship was established between EC and OH⁻ for these snow pits and ice cores. Positive correlation is also established between EC and major cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺). Since the cations are known as the proxies for the intensity of mineral dust influx onto glaciers of the northern Qinghai-Xizang Plateau, we believe that EC could be used as an indicator for the history of dust input in deep ice core study. In fact, records in Guliya ice core since the Little Ice Age (LIA) indicate that dust load in glacier may depend on the combination of temperature and humidity. “Cold-dry” combination favors the dust arising, and results in higher EC and OH⁻ values, while “warm-wet” combination prevents dust form and EC and OH⁻ values are lower. In the past century, with the atmospheric warming and precipitation increasing over the northern plateau, which means an atmospheric condition of dust decreasing, both EC and OH⁻ displayed rapid decline.  相似文献   

Linkage of liquid conductivity of glacier ice with its alkalinity over the north Qinghai-Xizang (Tibet) Plateau--Implication to the past dust recovery     

效存德  姚檀栋  秦大河  Katsumoto Seko  蒲健辰  盛文坤 《中国科学D辑(英文版)》2002,45(4)

Liquid conductivity (EC) measurement was conducted for the samples collected from several snow pits and ice cores over the Qinghai-Xizang (Tibet) Plateau, with their time range covering seasonal, decadal and centennial scales. Unlike the previous attention mostly focused on the acidity (H+) responding to the solid conductance (ECM) of glacial ice, we introduce the alkalinity (OH?) of snow and ice to show how it responds to EC. Strong linear relationship was established between EC and OH? for these snow pits and ice cores. Positive correlation is also established between EC and major cations (Ca2+, Mg2+, Na+ and K+). Since the cations are known as the proxies for the intensity of mineral dust influx onto glaciers of the northern Qinghai-Xizang Plateau, we believe that EC could be used as an indicator for the history of dust input in deep ice core study. In fact, records in Guliya ice core since the Little Ice Age (LIA) indicate that dust load in glacier may depend on the combination of temperature and humidity. "Cold-dry" combination favors the dust arising, and results in higher EC and OH- values, while "warm-wet" combination prevents dust form and EC and OH- values are lower. In the past century, with the atmospheric warming and precipitation increasing over the northern plateau, which means an atmospheric condition of dust decreasing, both EC and OH- displayed rapid decline.  相似文献   

The DA+dMe eclipsing binary EC13471–1258: its cup runneth over … just     

D. O'Donoghue  C. Koen  D. Kilkenny  R. S. Stobie  D. Koester  M. S. Bessell  N. Hambly  H. MacGillivray 《Monthly notices of the Royal Astronomical Society》2003,345(2):506-528

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Three new pulsating sdB stars from the Edinburgh–Cape survey     

D. Kilkenny  R. S. Stobie  D. O'Donoghue  C. Koen  N. Hambly  H. MacGillivray  A. E. Lynas-Gray 《Monthly notices of the Royal Astronomical Society》2006,367(4):1603-1608

We report the discovery of very rapid pulsations in three sdB stars from the Edinburgh–Cape blue object survey. The short periods, small amplitudes and multi-periodicity clearly establish these stars as members of the EC 14026 class. EC 11583−2708 has pulsation periods near 149, 144 and 114 s, though evidence is presented that the 149-s period is resolved into two periods at 148.87 and 148.55 s by the full photoelectric data set. The amplitudes of the detected variations are in the range 0.002–0.006 mag. The light variation of EC 20338−1925 is dominated by a period near 147 s with a very large amplitude for a variable sdB star (0.025 mag), though four other frequencies are detected with periods near 168, 151, 141 and 135 s and amplitudes in the range 0.002–0.005 mag. The third star, EC 09582−1137, displays a light curve which is virtually a textbook example of frequency beating, being produced by two pulsations of almost equal amplitude (∼0.008 mag) and periods near 136.0 and 151.2 s.  相似文献   

Hydrochemical characteristics and solute dynamics of meltwater runoff of Urumqi Glacier No.1, eastern Tianshan, northwest China   总被引：2，自引：0，他引：2  

Fang Feng  Zhongqin Li  Shuang Jin  Zhiwen Dong  Feiteng Wang 《山地科学学报》2012,9(4):472-482

Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007.The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7.61 in 2006 and 2007,respectively.In the meltwater,the dominant anions were the bicarbonate and sulphate,and the dominant cation was calcium.The concentration of major cations were varied as c(Ca2+) > c(Mg2+) > c(K+) > c(Na+),while the order for the cations was c(HCO3) > c(SO42) > c(NO3) > c(Cl).The total dissolved solids(TDS) in meltwater had inverse relationships with the diurnal discharge.The major ion composition of meltwater was mainly controlled by rock weathering as inferred from the Gibbs model.Furthermore,the ion ratios and Piper diagram indicated that the main processes controlling the meltwater chemistry were carbonate weathering,pyrite weathering and feldspar weathering in rocks,and Ca2+ and HCO3 were the dominant ions during the carbonate weathering process.Solute flux calculation at Glacier No.1 station suggested that chemical denudation rates were 11.46 and 13.90 ton.km 2.yr 1 in 2006 and 2007,respectively.  相似文献   

北京乡村地区分粒径气溶胶OC及EC分析   总被引：2，自引：0，他引：2       下载免费PDF全文

颜鹏  郇宁  张养梅  周怀刚 《应用气象学报》2012,23(3):285-293

利用北京上甸子区域大气本底站2004年观测的分粒径大气气溶胶资料,分析了气溶胶中有机碳 (OC) 及元素碳 (EC) 的质量浓度水平、季节变化、尺度分布特征、OC与EC比值及其相关性。结果显示:上甸子站总悬浮颗粒物 (TSP) 中OC平均质量浓度为7.5~31.5 μg·m-3,EC质量浓度为1.4~6.6 μg·m-3;PM_2.1(粒径小于2.1 μm) 中OC质量浓度为4.0~19.1 μg·m-3,EC质量浓度大约为0.8~4.3 μg·m-3。冬季OC及EC质量浓度明显高于其他季节,其中冬、夏、秋季OC及EC峰值粒径出现为0.65~2.1 μm,但在春季峰值粒径移至2.1~4.7 μm。观测期间,OC与EC质量浓度比值平均为4~6,该比值略高于文献报道的我国一些城市地区的观测结果。  相似文献   

保定市大气颗粒物中含碳组分粒径分布   总被引：5，自引：0，他引：5  

郭育红  辛金元  王跃思  温天雪  李杏茹 《气候与环境研究》2014,19(2):185-192

北京-天津-河北地区工业城市保定大气颗粒物(Particulate matter,PM)污染严重,保定大气颗粒物尤其是细粒子和超细粒子污染严重,其中含碳组分具有重大贡献,PM1.1、PM2.1和PM2.1-9.0中含碳气溶胶总量(total carbonaceous aerosols,TCA)分别占到(49±20)%、(45±19)%和(19±7)%。PM9.0中的含碳气溶胶主要富集在PM2.1乃至PM1.1中。颗粒物浓度谱分布及含碳气溶胶富集量呈显著季节变化,由于采暖过程秋冬季各粒径段有机碳(organic carbon,OC)和元素碳(elemental carbon,EC)的浓度均增加,秋、冬季节细颗粒物中OC浓度可高达44.0±38.3、78.5±30.2μg m-3,EC浓度分别为3.5±1.6、8.5±6.8μg m-3。各个季节OC和EC在总悬浮颗粒物(total suspended particulate,TSP)中的几何平均直径(geometric mean diameter,GMD)均集中在较小粒径段。粗颗粒物中OC的GMD在春夏季较高,秋季减少,而冬季最低。而粗颗粒物中EC的GMD则是冬季最高,夏季最低。保定0.4μm的颗粒物中OC/EC比值4个季节的水平较为稳定,春、夏、秋、冬季OC/EC比值分别为5.2、3.5、4.1和5.4,来源主要为交通和燃煤。其余几个粒径段的颗粒物的来源更为复杂,其来源主要为燃煤、木材和生物质。  相似文献