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排序方式: 共有103条查询结果,搜索用时 15 毫秒
91.
自动气象站日地面数据文件的维护和备份   总被引:1,自引:0,他引:1       下载免费PDF全文
每天20时编发报后,台站都要对当日定时的数据采集、报编发时保存在B件的资料进行维护。输入无遥测项目的人工观测项目记录,并从自动站数据件中读取数据,完成各项目的日统计。一般情况下,数据不需要替换,以B件为准。只有当某个时次要素不为空,且与Z件中的数据不一致时;或出现B件中个别时次无数据而要用Z件数据来代替B件时,才进行替换。所需替换的内容地面测报软件会自动列出,只有选中数据再点击“替换”才会生效,然后存盘。数据替换时,应注意以下几点。  相似文献   
92.
The artificial mussel (AM), a novel chemical sampling device, has been developed for monitoring dissolved trace metals in marine environments. The AM consists of Chelex-100 suspended in artificial seawater within Perspex tubing and enclosed with semi-permeable polyacrylamide gel at both ends. To validate the field performance of the AM in temperate waters, we deployed AMs alongside transplanted blue mussels Mytilus edulis in coastal environments in Scotland (Holy Loch, Loch Fyne, Loch Striven and Millport) and Iceland (Reykjavikurh?fn, Gufunes, South of thornerney, Hofsvik, Hvalfj?rethur and Sandgerethi) for monitoring trace metals. While uptake patterns of Cd between the AM and M. edulis were highly comparable, discrepancies were found in the accumulation profiles of the other metals (Cu, Cr, Pb and Zn), in particular Zn. Nonetheless, the AMs gave a better resolution to accurately reveal the spatial difference in dissolved metal contamination when compared with M. edulis. AMs complement the use of mussels since AMs indicate dissolved metals in seawater, whereas uptake by mussels indicates a mixture of dissolved and particulate metals. Our results also indicated that historical metal exposure of the transplanted M. edulis could significantly confound their metal concentrations especially when the deployment period was short (i.e. <34d). This study suggested that the AM can overcome problems associated with variable biological attributes and pre-exposure history in the mussel, and provides a standardized and representative time-integrated estimate of dissolved metal concentrations in different marine environments.  相似文献   
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Sediment cores were taken at three locations in Narragansett Bay, Rhode Island, USA in 1997 and analyzed for a variety of organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlordanes, linear alkyl benzenes (LABs), benzotriazoles (BZTs) and dichlorodiphenyltrichloroethanes (DDTs) and metabolites. The distributions of these chemicals at Apponaug Cove and in the Seekonk River indicate that there was a disturbance in the depositional environment relative to cores collected at these locations in 1986 demonstrating the potential for buried contaminants to be remobilized in the environment even after a period of burial. Sharp breaks in the concentration of several organic markers with known dates of introduction were successfully used to determine the sedimentation rate at Quonset Point. Both the Quonset Point and Seekonk River cores had subsurface maximums for DDTs, PCBs, PAHs and BZTs, which are consistent with expected inputs to the environment. The Apponaug Cove core showed an increase of most contaminants at the surface indicating a recent event in which more contaminated sediments were deposited at that location.  相似文献   
95.
与裂谷有关的极小正断层组分的几何形态和比例关系RoyW.Schlisch等过去十年中断层组分一直是广泛研究的主题。许多工作集中于确定断层组分的比例关系,包括断层尺寸的分布,位移和长度之间的关系,以及断层作用容纳的应变。许多断层组分表现出断层规模的幂函...  相似文献   
96.
青藏高原东部地壳运动的GPS测量   总被引:11,自引:0,他引:11  
在青藏高原晚新生代隆升过程中形成了一系列走滑断裂,这些断裂是否驱使地壳块体向东作长距离的滑移或逃逸,并成为东亚大陆及相邻海域地质构造的主要动力因素,是当前地学界关注的重大科学命题。对此,出现了众说纷  相似文献   
97.
Katz.  RW 陈柏林 《气象科技》1999,(1):31-39,44
简单的随机模式拟合的日降水量时间序列具有过低估计月(或季)总降水观察(或年际)变化的显著趋势。研究发展一种称为链相关过程的特殊类型的随机模式,估计了“超离差(overdispersion)”现象的程度,这种现象可归因子模式对降水的高频变化考虑不充分。对加利福尼亚奇科(Chico,California)1月份日降水量,拟合更复杂的随机模式,大大地减少月总降水方差的过程估计,通过利用日降水出现的高阶马  相似文献   
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Zhang Y  Gillham RW 《Ground water》2005,43(1):113-121
Long-term reactivity and permeability are critical factors in the performance of granular iron permeable reactive barriers (PRBs). Thus it is a topic of great practical importance, as well as scientific interest. In this study, four types of source solutions (distilled H2O, 10 mg/L TCE, 300 mg/L CaCO3, and 10 mg/L TCE + 300 mg/L CaCO3) were supplied to four columns containing a commercial granular iron material. In all four columns, gases accumulated to approximately 10% of the initial porosity and resulted in declines in permeability of approximately 50% to 80%. In the columns receiving CaCO3, carbonate precipitates accumulated to approximately 7% of the initial porosity, with no apparent decline in permeability. The data indicate that precipitates formed initially at the influent ends of the columns, reducing the reactivity of the iron in this region. As a consequence of the reduced reactivity, calcium and bicarbonate migrated further into the column, to precipitate in a region where the reactivity remained high. Thus precipitation occurred as a moving front through the columns. The results suggest improved methods for PRB design and rehabilitation, and also suggest improvements that are needed in the mathematical models developed for predicting long-term performance.  相似文献   
100.
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