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1.
Three-dimensional electromagnetic cross-well inversion 总被引:1,自引:0,他引:1
An inversion algorithm for a vertical magnetic dipole source and a vertical magnetic field component receiver is presented. A three-dimensional integral equation algorithm is used for calculating the electromagnetic response of a particular trial reservoir model. The inversion formalism used is the Marquardt technique of nonlinear least-squares optimization. The system derivatives are calculated using an exact expression derived from reciprocity. The derivative calculation involves introducing sources at the receiver locations with subsequent back-substitution into the impedance matrix equation. The inversion algorithm was tested on data gathered with a laboratory scale model. Convergence to the neighborhood of the correct model from distant initial trial models is good 相似文献
2.
Pollutant detachment rates have been determined for four chloride salts during simulated urban storm runoff. Under rainfall and/or overland flow conditions, chloride mass flux was measured and related to boundary shear stress of the test surface. Washoff coefficients, presumed to depend only on pollutant characteristics, were computed based on the slopes of dimensionless mass flux versus dimensionless time plots. Washoff coefficients were found to vary among and between the chloride compounds studied. In general, higher overland flow rates produced lower boundary shear and lower washoff coefficients. The combination of simulated rainfall and overland flow resulted in an increased boundary shear and an increased washoff coefficient. An empirical washoff coefficient based on a load characteristic curve derived from an exponential washoff relationship was also computed from the runoff data and compared with the previous washoff coefficient. A linear correlation between these two washoff coefficients was observed. The magnitude of the latter coefficient under simulated rainfall was consistent with reported values obtained from field data. 相似文献
3.
The Importance of Shallow‐Low Velocity Habitats to Juvenile Fish in the Middle Mississippi River
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Habitat management is a crucial aspect of fisheries management. Without knowledge of habitat associations, fisheries scientists are unable to effectively make habitat conservation or restoration recommendations. This becomes especially prominent when trying to manage commercially harvested populations and protect threatened or endangered species. To determine juvenile fishes habitat associations in the Middle Mississippi River, we analysed mini‐trawl catch data of six common juvenile fish species: blue catfish (Ictalurus furcatus), channel catfish (Ictalurus punctatus), channel shiner (Notropis wickliffi), freshwater drum (Aplodinotus grunniens), paddlefish (Polyodon spathula), and shovelnose sturgeon (Scaphirhynchus platorynchus). Overall, we conducted 2251 mini‐trawl sampling efforts between 2002 and 2013, resulting in the capture of 23,742 target specimens. Catch per unit effort was evaluated by structural habitat (i.e. velocity, depth, and substrate). Overall, these data suggest that juvenile fish species are more prevalent in shallow water and slower velocities. Ultimately the information garnered during this evaluation should be incorporated when considering habitat modifications, especially those modifications that impact the availability of shallow‐low velocity habitats. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
G. J. Boudreaux A. V. Bailey V. W. Tripp 《Journal of the American Oil Chemists' Society》1972,49(3):200-201
The use of a pseudo contact shift reagent, (Eu[fod]3), to obtain simplified NMR spectra of a typical long chain monounsaturated fatty acid methyl ester, methyl petroselinate,
is described. Spectra were obtained in which individual methylene groups are identifiable from their splitting patterns. Non-equivalent
splitting patterns were observed for the methine protons with varying amounts of reagent used. The effect of concentration
of the shift reagent on the chemical shift is discussed.
Presented in part at the Meeting of the Gulf Coast Instrumental Analysis Group, Houston, October 1971.
S. Market. and Nutr. Res. Div., ARS, USDA 相似文献
5.
6.
A streak camera technique with temporal resolution of 20 ps has been used to measure the fluorescence properties of several subnanosecond plastic scintillators. The method employs a vacuum light pipe coupled to an optical streak camera. The scintillators are excited by a 200-ps x-ray pulse generated by a 1.06-microm Nd:YAG laser focused onto an iron target. The time history of the low-energy x-ray pulse is measured with an x-ray streak camera. Results are given for NElll plastic scintillators doped with benzophenone or acetophenone, for PVT doped with butyl-PBD, and for a ZnO phosphor doped with Ga. 相似文献
7.
RA Tripp AM Hamilton-Easton RD Cardin P Nguyen FG Behm DL Woodland PC Doherty MA Blackman 《Canadian Metallurgical Quarterly》1997,185(9):1641-1650
The murine gamma-herpesvirus 68 has many similarities to EBV, and induces a syndrome comparable to infectious mononucleosis (IM). The frequency of activated CD8+ T cells (CD62L(lo)) in the peripheral blood increased greater than fourfold by 21 d after infection of C57BL/6J (H-2(b)) mice, and remained high for at least a further month. The spectrum of T cell receptor usage was greatly skewed, with as many as 75% of the CD8+ T cells in the blood expressing a Vbeta4+ phenotype. Interestingly, the Vbeta4 dominance was also seen, to varying extents, in H-2(k), H-2(d), H-2(u), and H-2(q) strains of mice. In addition, although CD4 depletion from day 11 had no effect on the Vbeta4 bias of the T cells, the Vbeta4+CD8+ expansion was absent in H-2IA(b)-deficient congenic mice. However, the numbers of cycling cells in the CD4 antibody-depleted mice and mice that are CD4 deficient as a consequence of the deletion of MHC class II, were generally lower. The findings suggest that the IM-like disease is driven both by cytokines provided by CD4+ T cells and by a viral superantigen presented by MHC class II glycoproteins to Vbeta4+CD8+ T cells. 相似文献
8.
A. V. Bailey D. Mitcham V. W. Tripp G. Sumrell 《Journal of the American Oil Chemists' Society》1976,53(3):89-89
X-ray powder diffraction data are presented for some normal alkyl esters of two octadecenoic acids. The crystal long spacings
observed for esters of elaidic acid are shown to be linearly related to the length of the carbon chain of the ester group.
Little difference in crystal long spacings was observed between esters ofcis andtrans acids. Melting points of alkyl esters of elaidic acid are reported. 相似文献
9.
Design techniques are presented for a class of circular magnetic hybrid-mode (MHM) horns together with experimental results. In comparison with earlier techniques, this design method is simpler and more amenable to physical interpretation. The horns designed exhibit performance comparable to that of the corrugated horn except that they have an ohmic loss of 0.8 to 2.7 dB. However, it appears feasible to reduce the gain loss to less than 1 dB 相似文献
10.
Tripp B.P. McIlroy W.E. Maki B.E. 《IEEE transactions on neural systems and rehabilitation engineering》2004,12(1):140-152
Stepping reactions are often triggered rapidly in response to loss of balance. It has been unclear whether spatial step parameters are defined at time of step-initiation or whether they can be modulated online, during step execution, in response to sensory feedback about the evolving state of instability. This study explored the capacity to actively alter step direction subsequent to step initiation in six healthy young-adult subjects. To elicit forward-step reactions, subjects were released suddenly from a tethered forward lean. A second perturbation (medio-lateral support-surface translation) was applied at lags of 0-200 ms. Active reaction to the second perturbation was determined primarily through analysis of swing-leg hip-abductor activation. In addition, to gauge the biomechanical consequence of the changes in muscle activation, we compared the measured medio-lateral swing-foot displacement to that predicted by a simple passive mechanical model. Perturbations at 0-100 ms lag evoked active medio-lateral swing-foot deviation, allowing balance to be recovered with a single step. However, when the second perturbation occurred near foot-off (200-ms lag), there was no evidence of active alteration of step direction and subjects typically required additional steps to recover balance. The results suggest that step direction can be reparameterized during early stages of stepping reactions, but that step direction was not actively modulated in response to perturbation arising near start of swing phase. 相似文献