The geology of continental margins: Edited by C. A. Burk and C. L. Drake. Springer,New York,N.Y., 1974, 1009 pp., $34.80     

D.A. McManus 《Marine Geology》1976,20(3):277-278

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The Ultimate CCD for Laser Guide Star Wavefront Sensing on Extremely Large Telescopes     

James W. Beletic  Sean Adkins  Barry Burke  Robert Reich  Bernie Kosicki  Vyshnavi Suntharalingham  Charlie Bleau  Ray DuVarney  Richard Stover  Jerry Nelson  Francois Rigaut 《Experimental Astronomy》2005,19(1-3):103-109

All of the extremely large telescopes (ELTs) will utilize sodium laser guide star (LGS) adaptive optics (AO) systems. Most of these telescopes plan to use the Shack-Hartmann approach for wavefront sensing. In these AO systems, the laser spots in subapertures at the edge of the pupil will suffer from spot elongation due to the 10 km extent of the sodium layer and the large separation from the projection laser. This spot elongation will severely degrade the performance of standard geometry wavefront sensing systems. In this paper, we present a CCD with custom pixel morphology that aligns the pixels of each subaperture with the radial extension of the LGS spot. This CCD design will give better performance than a standard geometry CCDs for continuous wave lasers. In addition, this CCD design is optimal for a pulsed sodium laser. The pixel geometry enables each subaperture to follow a laser pulse traversing the sodium layer, providing optimal sampling of a limited number of detected photons. In addition to novel pixel layout, this CCD will also incorporate experimental JFET sense amplifiers and use CMOS design approaches to simplify the routing of biases, clocks and video output. This CCD will attain photon-noise limited performance at high frame rates, and is being incorporated in the plans for the Thirty Meter Telescope (TMT).  相似文献   

Comparison of Electrical Resistivity Methods for Investigation of Ground Water Conditions at a Landfill Site   总被引：1，自引：0，他引：1  

Jerry J. Sweeney 《Ground Water Monitoring & Remediation》1984,4(1):52-59

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Opening GIScience: A process-based approach     

Jerry Shannon  Kyle Walker 《International journal of geographical information science》2018,32(10):1911-1926

Many scholars have demonstrated growing interest in GIScience in recent years, including use of open data portals, shared code and options for open access publication. These practices have made both research and data more transparent and accessible for a broad audience. This research may be open only in a limited sense for populations without expertise in the technology and methods undergirding these data. Based on two case studies using RStudio’s Shiny web platform, we argue that a process-based approach focusing on how analysis is opened throughout the research process provides a supplementary way to define and reflect upon public facing geographic research. Reflecting upon decisions we made at key points in each case study project, we identify four key tensions inherent to work in open GIScience: standardized vs. flexible tools, expert vs. community-led design, single vs. multiple audiences and established vs. emerging metrics.  相似文献   

Annual variations in water storage and precipitation in the Amazon Basin   总被引：1，自引：0，他引：1  

John W. Crowley  Jerry X. Mitrovica  Richard C. Bailey  Mark E. Tamisiea  James L. Davis 《Journal of Geodesy》2008,82(1):9-13

We combine satellite gravity data from the gravity recovery and climate experiment (GRACE) and precipitation measurements from the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center’s (CPC) Merged Analysis of Precipitation (CMAP) and the Tropical Rainfall Measuring Mission (TRMM), over the period from mid-2002 to mid-2006, to investigate the relative importance of sink (runoff and evaporation) and source (precipitation) terms in the hydrological balance of the Amazon Basin. When linear and quadratic terms are removed, the time-series of land water storage variations estimated from GRACE exhibits a dominant annual signal of 250 mm peak-to-peak, which is equivalent to a water volume change of ~1,800 km³. A comparison of this trend with accumulated (i.e., integrated) precipitation shows excellent agreement and no evidence of basin saturation. The agreement indicates that the net runoff and evaporation contributes significantly less than precipitation to the annual hydrological mass balance. Indeed, raw residuals between the de-trended water storage and precipitation anomalies range from ±40 mm. This range is consistent with stream-flow measurements from the region, although the latter are characterized by a stronger annual signal than our residuals, suggesting that runoff and evaporation may act to partially cancel each other.  相似文献   

The role of fluvial geomorphic processes in the dispersal of heavy metals from mine sites     

Jerry R. Miller 《Journal of Geochemical Exploration》1997,58(2-3)

It is not uncommon for more than 90% of the total metal load in rivers to be transported in the solid phase, either sorbed onto particle surfaces and coatings, or incorporated into mineral grains. Fluvial geomorphic processes are therefore of fundamental importance in the transport and fate of heavy metals derived from mine sites. In this paper, the role of physical processes in the dispersal of heavy metals in river systems are reviewed for channels that have (1) remained relatively unchanged in terms of process and form following the introduction of mine wastes, and (2) exhibited a significant metamorphosis in channel form in response to the influx of mining and milling debris. In general, all processes responsible for the variations in metal concentrations within sediments moving through stable channels also operate in channels undergoing metamorphosis. However, downstream, lateral, and vertical patterns in metal values tend to be more complex where channel transformations have occurred. This complexity results, in part, because temporal and spatial changes in the types, rates, and magnitudes of erosional and depositional processes lead to highly variable stratigraphic sequences of post-mining age, and because greater quantities of contaminated debris is stored along the channel margins where it can be eroded and sporadically redistributed during times of flood.  相似文献   

Storage Coefficients and Vertical Hydraulic Conductivities in Aquitards Using Extensometer and Hydrograph Data   总被引：2，自引：0，他引：2  

Theodore G. Cleveland  Rolando Bravo  Jerry R. Rogers 《Ground water》1992,30(5):701-708

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Globes: 400 Years of Exploration,Navigation, and Power     

Jerry T. Mitchell 《The Journal of geography》2016,115(1):35-36

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Green and sustainable remediation practices in Federal Agency cleanup programs     

Louis E. Martino  Carol L. Dona  Jerry Dicerbo  Amy Hawkins  Beth Moore  Robert Horner 《Environmental Earth Sciences》2016,75(21):1407

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Aspirations and common tensions: larger lessons from the third US national climate assessment     

Susanne C. Moser  Jerry M. Melillo  Katharine L. Jacobs  Richard H. Moss  James L. Buizer 《Climatic change》2016,135(1):187-201

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