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Ben L. O’Connor Miki Hondzo Judson W. Harvey 《Canadian Metallurgical Quarterly》2009,135(12):1304-1314
Traditionally, dissolved oxygen (DO) fluxes have been calculated using the thin-film theory with DO microstructure data in systems characterized by fine sediments and low velocities. However, recent experimental evidence of fluctuating DO concentrations near the sediment-water interface suggests that turbulence and coherent motions control the mass transfer, and the surface renewal theory gives a more mechanistic model for quantifying fluxes. Both models involve quantifying the mass transfer coefficient (k) and the relevant concentration difference (ΔC). This study compared several empirical models for quantifying k based on both thin-film and surface renewal theories, as well as presents a new method for quantifying ΔC (dynamic approach) that is consistent with the observed DO concentration fluctuations near the interface. Data were used from a series of flume experiments that includes both physical and kinetic uptake limitations of the flux. Results indicated that methods for quantifying k and ΔC using the surface renewal theory better estimated the DO flux across a range of fluid-flow conditions. 相似文献
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Harvey Elizabeth A.; Youngwirth Sara D.; Thakar Dhara A.; Errazuriz Paula A. 《Canadian Metallurgical Quarterly》2009,77(2):349
The present study examined the power of measures of early preschool behavior to predict later diagnoses of attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD)/conduct disorder (CD). Participants were 168 children with behavior problems at age 3 who underwent a multimethod assessment of ADHD and ODD symptoms and were followed annually for 3 years. Fifty-eight percent of 3-year-old children with behavior problems met criteria for ADHD and/or ODD/CD 3 years later. Using a diagnostic interview and rating scales at age 3, the authors could accurately predict later diagnostic status for 3/4 of children for ADHD and for 2/3 of children for ODD/CD. Predictive power of the best models did not increase significantly at age 4 and age 5 compared with age 3. Results provide support for the validity of early diagnoses of ADHD, although caution is needed in making diagnoses because a significant minority of children with early hyperactivity and inattention do outgrow their problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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The first objective of this paper investigates the influence of the previous strain history on ratcheting. New tests were performed where different strain-controlled histories have been applied prior to ratcheting tests. It is demonstrated that under the same conditions, one can observe ratcheting, plastic shakedown or elasticity according to the prior strain-controlled history. The second objective points out the correlation between the experimental data base devoted to the identification of the material parameters and the quality of the predictions in cyclic plasticity. The results suggest that the choice of the tests should be closely linked to the capabilities of the model. In particular, the presence of non proportional strain-controlled tests in the data base may be not a good choice if the model itself is not able to represent explicitly such a character. All tests considered here were performed on 304L SS at room temperature. 相似文献
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David J. Harvey 《Mass spectrometry reviews》2011,30(1):1-100
This review is the fourth update of the original review, published in 1999, on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2006. The review covers fundamental studies, fragmentation of carbohydrate ions, method developments, and applications of the technique to the analysis of different types of carbohydrate. Specific compound classes that are covered include carbohydrate polymers from plants, N‐ and O‐linked glycans from glycoproteins, glycated proteins, glycolipids from bacteria, glycosides, and various other natural products. There is a short section on the use of MALDI‐TOF mass spectrometry for the study of enzymes involved in glycan processing, a section on industrial processes, particularly the development of biopharmaceuticals and a section on the use of MALDI–MS to monitor products of chemical synthesis of carbohydrates. Large carbohydrate–protein complexes and glycodendrimers are highlighted in this final section. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:1–100, 2011 相似文献
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Harvey M. Jacobs 《Journal of the American Planning Association. American Planning Association》2013,79(2):181-189
The private property rights movement was one of the most consequential land use and environmental movements of the 1990s. It first emerged on the national sphere in the latter years of the Reagan administration. Advocates shifted their focus to the state level during the Bush and Clinton presidencies. In 2000 they provided strong support for George W. Bush's candidacy, with high expectations from his administration. This commentary examines the national-level property rights activity of the Bush administration in 2001 and 2002 and speculates on the prominence and success of this policy sphere in this administration's future. 相似文献
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Michael Knorr Fabrice Guyon Abderrahim Khatyr Magali Allain Shawkat M. Aly Antony Lapprand Daniel Fortin Pierre D. Harvey 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(3):534-543
Abstract
CuI reacts instantaneously with butanedithiol in MeCN solution to form a sparingly soluble and thermally stable colorless polymeric material 1 of composition [(Cu2I2){HS(CH2)4SH}] n . Raman and IR spectroscopy confirm the presence of Cu(I) bound S–H functions. Furthermore, small amounts of the yellow compound [{Cu(μ2-I)2Cu}(C4H8S2)2] n 2 co-crystallize after several days. If the reaction mixture is exposed to air, polymeric 2 is isolated as the main product. An X-ray diffraction study reveals that 1D polymer 2 is assembled by rhomboid Cu(μ2-I)2Cu clusters (d Cu···Cu 2.6843(18) ?), which are linked through the S-atoms of six-membered 1,2-dithian heterocycles, thus generating an infinite ribbon. The low-frequency region in the Raman spectra show a striking similarity suggesting that polymers 1 and 2 bear the same cluster rhomboid Cu(μ2-I)2Cu clusters. The photophysics and luminescence properties of 2 have been studied experimentally and by means of DFT/TDDFT calculations. 相似文献30.