The isolated non-circular ringlets of Saturn     

Jay Roderick Hill  D. A. Mendis 《Earth, Moon, and Planets》1982,26(2):217-226

We show that the combined effect of electrodynamic and gravitational forces can account for a number of features observed by Voyagers 1 and 2 in the isolated fine dust rings of Saturn. These include (a) the appearance and disappearnce of the braids in the F-ring, (b) the eccentricities of the F-ring and the ringlets within the Encke and Cassine divisions and a gap in the C-ring, and (c) the kinks in the eccentric Encke ring. They may also account for the very existence of these rings.  相似文献   

REPLY     

A. David Hill 《The Professional geographer》1982,34(1):92-92

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On the braids and spokes in Saturn's ring system     

Jay Roderick Hill  D. A. Mendis 《Earth, Moon, and Planets》1981,24(4):431-436

Two of the features in the Saturnian ring system recently observed by the Voyager 1 spacecraft are (a) the braiding of theF-ring and (b) the radial spokes that rotate across theB-ring. Both of these phenomena are explained by recognizing that the grains that constitute both theF-ring and the spokes are charged to high electrostatic potentials and are sufficiently small to be strongly affected by the magnetic field of the planet. Processes for the charging of the grains are also suggested.  相似文献   

The dynamic response of the two-electrode conductivity cell     

Hill  K.D. Woods  D.J. 《Oceanic Engineering, IEEE Journal of》1988,13(3):118-123

The dynamic response of the two-electrode conductivity cell in the dual-needle configuration of M.C. Gregg et al. (1981) was investigated both theoretically and experimentally. A theory is presented which answers fundamental questions regarding the effective cell volume and the mathematical form of the transfer function. These characteristics are shown to be functionally dependent on the spacing between the wires. Experimental determinations of cell response were performed with a thermal plume as the stimulus rather than with the step-response-in-salinity method of Gregg et al. The data are shown to confirm the theoretical form of the transfer function.<>  相似文献   

Detection of individual normal modes of oscillation of the Sun in the period range from 2 hr to 10 min in solar diameter studies     

Bos  Randall J.  Hill  Henry A. 《Solar physics》1983,82(1-2):89-102

Solar Physics - New observations of solar oscillations are reported. Power density spectra derived from these observations reveal narrow-band oscillations that are spatially global, have spatial...  相似文献   

A SURVEY OF THE GLOBAL UNDERSTANDING OF AMERICAN COLLEGE STUDENTS: A REPORT TO GEOGRAPHERS     

A. David Hill 《The Professional geographer》1981,33(2):237-245

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The NOAA Goes-12 Solar X-Ray Imager (SXI) 2. Performance     

V. J. Pizzo  S. M. Hill  C. C. Balch  D. A. Biesecker  P. Bornmann  E. Hildner  R. N. Grubb  E. G. Chipman  J. M. Davis  K. S. Wallace  K. Russell  S. A. Cauffman  T. T. Saha  G. D. Berthiume 《Solar physics》2005,226(2):283-315

The Solar X-ray Imager (SXI) was launched on 23 July 2001 on NOAAs GOES-12 satellite and completed post-launch testing on 20 December 2001. It was brought into operations on 21 January 2003. This paper documents SXI performance and calibrations prior to an instrument degradation that occurred on 5 November 2003 and thus covers more than 420000 soft X-ray images of the Sun. This paper details component-level as well as full-system calibrations characterizing the spatial and spectral performance of the instrument, including the grazing-incidence mirror, filters, and the properties of the MCP-intensified CCD detector system. Routine image corrections are also described. These include background (dark current) subtraction, flat-fielding, off-band light-leak correction, and image pointing and timing considerations. In addition, a signal-to-noise analysis is presented. The information contained in this study is intended to enable researchers to conduct quantitative analysis of GOES-12 SXI images.  相似文献   

Laboratory investigation of the effects of mineral size and concentration on the formation of oil-mineral aggregates     

Ajijolaiya LO  Hill PS  Khelifa A  Islam RM  Lee K 《Marine pollution bulletin》2006,52(8):920-927

Controlled laboratory studies of the formation of oil-mineral aggregates (OMA) in seawater demonstrate that sediment concentration and sediment size are key variables for determining the quantity of oil droplets stabilised by OMA formation. Experiments with a single sediment size and a range of sediment concentrations show that as sediment concentration increases, the quantity of oil trapped in OMA increases abruptly. In experiments with a single sediment concentration and a range of sediment sizes, the quantity of oil trapped in OMA decreases as sediment size increases. These results provide direct support to the hypothesis that there is a critical sediment concentration for OMA formation. Below this concentration, stabilisation of oil droplets by OMA decreases rapidly, while above this concentration, stabilisation is extensive. The results also support simple geometric models of OMA formation that predict that the critical sediment mass concentration increases linearly with sediment particle diameter. These results will help to place quantitative constraint on predictions of where and when OMA formation will be a factor in the natural dispersal of oil accidentally spilled into the ocean.  相似文献   

The electronic bands of CrD, CrH, MgD and MgH: application to the 'deuterium test'     

Ya. V. Pavlenko  G. J. Harris  J. Tennyson  H. R. A. Jones  J. M. Brown  C. Hill  L. A. Yakovina 《Monthly notices of the Royal Astronomical Society》2008,386(3):1338-1346

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Mediterranean desertification and land degradation: Mapping related land use change syndromes based on satellite observations   总被引：3，自引：0，他引：3  

J. Hill  M. Stellmes  Th. Udelhoven  A. Rder  S. Sommer 《Global and Planetary Change》2008,64(3-4):146

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