美国全球变化研究计划—1992年财政年度计划的概述和展望     

Core.  RW 倪建红 《大气情报》1992,(27):47-51

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Modeling multiscale heterogeneity and aquifer interconnectivity   总被引：2，自引：0，他引：2  

Proce CJ  Ritzi RW  Dominic DF  Dai Z 《Ground water》2004,42(5):658-670

A number of methods involving indicator geostatistics were combined in a methodology for characterizing and modeling multiscale heterogeneity. The methodology circumvents sources of bias common in data from borehole logs. We applied this methodology to the complex heterogeneity within a regional system of buried valley aquifers, which occurs in the western glaciated plains of North America and includes the Spiritwood Aquifer. The region is conceptualized as having a hierarchical organization with three facies assemblage types (large-scale heterogeneity) and two facies types within each assemblage (small-scale heterogeneity). We statistically characterized the sedimentary architecture at both scales, formulated indicator correlation models from those characterizations, and used the models to simulate the architecture in a multiscale realization. We focused on the interconnectivity of units creating higher-permeability pathways. Higher-permeability pathways span the realization even though the proportion of higher-permeability facies is less than the percolation threshold. Thus, geologic structures as represented in the indicator correlation models create interconnectivity above that which would occur if the higher-permeability facies were randomly placed. This amount of interconnection among higher-permeability facies within the multiscale realization is consistent with that suggested in prior hydraulic and geochemical studies of the regional system.  相似文献   

A reassessment of ground water flow conditions and specific yield at Borden and Cape Cod     

Gillham RW  Roy JW 《Ground water》2004,42(3):456-457

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The distribution and sources of polycyclic aromatic hydrocarbons in Narragansett Bay surface sediments   总被引：9，自引：0，他引：9  

Hartmann PC  Quinn JG  Cairns RW  King JW 《Marine pollution bulletin》2004,48(3-4):351-358

Polycyclic aromatic hydrocarbons (PAHs) were measured in 41 surface sediments from Narragansett Bay, RI. All the analytes generally decrease down bay from the Seekonk, Providence and Taunton Rivers at the head of the bay. Total PAHs ranged from 0.569 to 216 microg/g with 27% exceeding the effects range median (ERM) of 44.8 microg/g and 73% of the stations exceeding the effects range low (ERL) of 4.02 microg/g (Long et al., 1995). Based on principal component analysis, the major source of the contaminants in Narragansett Bay was the Providence River while the coves and Taunton River/Mt. Hope Bay appeared to only have a limited influence on the open bay. PAH source ratios indicate that creosote and/or coal may be the most significant contributor of pyrogenic high molecular weight PAHs in Narragansett Bay, along with significant contributions from diesel exhaust.  相似文献   

Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301     

Mathur S  Green PJ  Arav N  Brotherton M  Crenshaw M  deKool M  Elvis M  Goodrich RW  Hamann F  Hines DC  Kashyap V  Korista K  Peterson BM  Shields JC  Shlosman I  van Breugel W  Voit M 《The Astrophysical journal》2000,535(2):L79-L82

We present results of new ASCA observations of the low-luminosity active galactic nucleus (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on the detection of variability of an iron K emission line. The X-ray luminosities in the 2-10 keV band for the two observations are nearly identical (LX approximately 2x1041 ergs s(-1)), but they are approximately 35% larger than that measured in 1995 July by Terashima et al. An Fe K emission line is detected at 6.39+/-0.09 keV (source rest frame), which is lower than the line energy 6.73+0.13-0.12 keV in the 1995 observation. If we fit the Fe lines with a blend of two Gaussians centered at 6.39 and 6.73 keV, the intensity of the 6.7 keV line decreases, while the intensity of the 6.4 keV line increases, within an interval of 3.5 yr. This variability rules out thermal plasmas in the host galaxy as the origin of the ionized Fe line in this LLAGN. The detection and variability of the 6.4 keV line indicates that cold matter subtends a large solid angle viewed from the nucleus and that it is located within approximately 1 pc from the nucleus. It could be identified with an optically thick standard accretion disk. If this is the case, a standard accretion disk is present at the Eddington ratio of Lbol/LEdd approximately 2x10-3. A broad disk-line profile is not clearly seen, and the structure of the innermost part of accretion disk remains unclear.  相似文献   

Organochlorine concentrations in resident bottlenose dolphins (Tursiops truncatus) in the Shannon estuary,Ireland     

Berrow SD  Mchugh B  Glynn D  Mcgovern E  Parsons KM  Baird RW  Hooker SK 《Marine pollution bulletin》2002,44(11):1296-1303

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Survival, growth, metallothionein and glycogen levels of Nucella lapillus (L.) exposed to subchronic cadmium stress: the influence of nutritional state and prey type     

Leung KM  Furness RW 《Marine environmental research》2001,52(2):173-194

Dogwhelks Nucella lapillus feed mainly on mussels and barnacles, and may experience periods of starvation. We report effects of nutritional state and prey type on the survival, growth, cadmium (Cd) accumulation, metallothionein (MT) induction and glycogen stores in N. lapillus exposed to Cd in water. Adult dogwhelks, with similar shell length (30.0+/-1.5 mm), were either starved or fed to satiation with barnacles Semibalanus balanoides, mussels Mytilus edulis or Cd-dosed M. edulis, and kept in filtered natural seawater (< 0.01 microg Cd 1(-1)) or Cd-contaminated (400 microg Cd 1(-1)) seawater for 80 days. Mortality and individual growth rate were determined. Cd, MT and glycogen were measured in different tissues. Prolonged starvation and exposure to Cd significantly reduced the survivorship of N. lapillus, but feeding could help dogwhelks to combat Cd toxicity and minimise mortality. Extended starvation also caused tissue wastage, leading to higher concentrations of Cd and MT in tissues, whereas fed animals increased in weight and had lower Cd and MT concentrations because of the tissue dilution effect. Prey type significantly affected growth rate of dogwhelks and indirectly influenced Cd accumulation, MT induction and glycogen stores. Eating mussels promoted better growth and higher glycogen reserves than eating barnacles. Individual growth rate decreased with increasing Cd accumulation. Cd-exposed survivors grew faster and consumed more than control animals, implying that these survivors may have better fitness and greater tolerance to Cd toxicity. The use of growth, condition index, MT and glycogen as biomarkers of environmental pollution are discussed. These results indicate a need to incorporate biological data including growth (or at least condition index) and prey type into biomonitoring programmes to allow sound interpretation.  相似文献   

一种在松散沉积层中采取水样的工具—水文穿孔器     

Edge  RW 陈礼宾 《水文地质技术方法》1990,(21):103-107,111

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地壳增长与壳—幔再循环     

Kay  RW 曲燕 《世界地质》1991,10(1):70-71

在会聚边缘的地壳增长目前是由地壳从地幔中的萃取作用所支配的,这是一个只能间接观察到的过程。在现代的会聚边缘,常见于地壳最上部的玄武岩和安山岩(及相应的侵入岩)并非直接源于地幔(如它们不是地幔的初始成分)。例如,在阿留申岛弧,橄榄拉斑玄武岩已被认作是初始岩浆,它与普通高铝玄武岩有关,而后者是由积聚在莫霍面深处的橄榄石和辉石的分离作用所形成的,并代表一个新生的上地幔,更常见的浅部富铝质火山岩及深成岩可以由高铝玄武岩的壳内组分分异、岛弧地壳低熔组分的同化、地壳熔融所形成,或者是诸过程结合的产物。每个岛弧真正的地壳剖面取决于岛弧  相似文献   

黑河地区地—气相互作用实验研究国际研讨会在兰召开     

倪建红  杨炎明 《地球科学进展》1988,(6)

在国家自然科学基金委员会、中国科学院和甘肃省科委的领导和支持下,由兰州高原大气物理研究所组织的“黑河地区地—气相互作用观测实验研究”国际研讨会于1988年9月1日—8日在兰州召开。著名科学家、学部委员叶笃正教授主持了会议,来自气象、地理、水利、农业等多个学科的中外科学家共51位代表参加了会议。会议围绕“黑河实验”的总体方案、黑河流域地区气候、地理背景和地面物理特征的研究,测量或计算近地面湍流通量的方  相似文献