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991.
William D. Stuart 《Tectonophysics》1979,52(1-4)
Episodic slip on shallow crustal faults can be qualitatively explained by postulating a fault constitutive law that is the superposition of two limiting material responses: (1) strain softening after peak stress during large strain rates, and (2) strength (peak stress) recovery during aging at small strain rates. A single law permits a variety of seismic and aseismic phenomena to occur over a range of space and time scales. Specific cases are determined by the spatial variation of material constants, recent deformation history, crustal rigidity, and remote forcing. 相似文献
992.
Passing landfill leachate through glauconitic greensand filters reduces the heavy metal cation content, lessens the unpleasant
odor, and diminishes the murkiness of the leachate. The capability of the greensand to trap metal cations is increased by
prolonging the contact time between the leachate and the greensand. Flushing the charged greensand filter with water does
not cause significant release of cations back into solution, suggesting that polluted greensand might be disposed of at landfill
sites without endangering the quality of either ground or surface water. 相似文献
993.
Experiments using distilled water, spiked with heavy metal cations and passed through a filtration system composed of greensand
containing 80% glauconite at a rate of 2–4 ml/min, showed: (1) starting fluids containing Cd, Co, Cu, Pb, Mn, Ni, Ag, or Zn
had an average of 90% of the contaminating cation removed from acidic solutions and an average of 84% removed from the basic
solutions; and, (2) filtration through greensand tended to neutralize both acidic and basic solutions. The removal of the
contaminant cation from starting fluids containing K, Na, Ca, Mg, Fe, Si, or Al (the principal constituents of glauconite
plus Ca from shell material) is not as consistently effective as for the first named metals. 相似文献
994.
R. P. Burgner Barry E. Scheetz William B. White 《Physics and Chemistry of Minerals》1978,2(4):317-324
An analysis has been made of the strong yellow luminescence of S 2 ? in the silicate mineral scapolite. The emission spectrum is dependent upon excitation wavelength, indicating that S 2 ? occupies several different sites. The vibrational constants for the ground state average 609 cm?1 for ω″0, while ω″0χ″0=2.2cm?1. For the excited state ω′0=399cm?1 and ω′0χ′0=1.0cm?1. The intensities of the vibrational bands are described by a simple harmonic oscillator calculation. 相似文献
995.
William R. Nicholson 《Estuaries and Coasts》1978,1(3):141-150
Over 968,000 adult Atlantic menhaden,Brevoortia tyrannus, were tagged from 1967 to 1969 and over 85,000 juvenile menhaden were tagged from 1969 to 1973. Recoveries of these tagged fish through 1975 provide direct evidence that Atlantic menhaden consist of a single population that over-winters in offshore waters off the southeastern coast of the United States, moves northward in spring and stratifies along the coast by age and size during summer, and moves southward in late autumn. 相似文献
996.
997.
James W. Murray Varis Grundmanis William M. Smethie 《Geochimica et cosmochimica acta》1978,42(7):1011-1026
Measurements of nutrients and trace metals are used to examine the processes controlling their distributions in the interstitial waters of Saanich Inlet. Samples were collected using both in situ and squeezing techniques with excellent agreement. Additional measurements of porosity, organic carbon and sedimentation rate by 210Pb are used in conjunction with the nutrient measurements to test the equation for the diagenesis of organic matter in fine-grained, organic-rich and rapidly-accumulating sediments.Organic carbon and sulfate decrease with depth in the sediment whereas ammonia and alkalinity increase. In the zone of sulfate reduction (0–20 cm) the rate constants for sulfate reduction (), ammonia production () and organic carbon decomposition () agree within a factor of two. Our calculations indicate, however, that this is fortuitous since the observed decrease in paniculate organic carbon is insufficient to account for the sulfate consumption. Sulfate must also be consumed by reaction with methane diffusing up from the underlying sediments. The rate constant for sulfate reduction using particulate organic carbon is lower than a modelled rate encompassing all organic species, including methane.The rate constant for ammonia production () decreases by an order of magnitude when sulfate is completely depleted and methane production dominates.Thermodynamic calculations suggest that the interstitial waters are saturated or supersaturated with respect to all forms of iron ‘monosulfides’, apatite and rhodochrosite. 相似文献
998.
999.
1000.
Diagonal damping matrices were computed for three systems which have non-proportional damping matrices. These diagonal damping matrices were computed on three bases, as follows: 1. After normalizing the equations of motion by the modal matrix, the diagonal terms are retained ignoring the non-diagonal terms. 2. Diagonal damping matrix is established by the optimization algorithm which minimizes the mean square error of the frequency response. 3. Diagonal damping is determined from the normalized differential equation by matching the peaks of the coupled and uncoupled system. The frequency responses for the three cases of one of the three systems are presented together with a comparison of the energy dissipation. 相似文献