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51.
C.E. Stronach K.R. Squire A.S. Arrott B.D. Patterson B. Heinrich W.F. Lankford A.T. Fiory W.J. Kossler J.J. Singh 《Journal of magnetism and magnetic materials》1981,25(2):187-193
The temperature dependence (240 to 633 K) of the interstitial magnetic field, Bμ, as determined by the rotation of the spin of the μ+, has been measured for dilute polycrystalline iron alloys with Mo, Ti and Nb additions. In all cases the behaviours differ from one another and from the Fe(A1) alloys previously studied. Bμ, which is negative with respect to the magnetization, is increased in magnitude by A1 and Mo, and decreased greatly by Ti. The addition of Nb creates a two- phase alloy from which we can assess the role of heterogeneity and/or strain on Bμ in iron. If the temperature dependence of the hyperfine field Bhf extracted from Bμ for Fe(Mo) alloys is interpreted on the model previously used to discuss the Fe(A1) data, we would conclude that the muon is attracted to the Mo atom while repelled by the A1 atoms as the temperature decreases. Measurements giving room temperature values of Bμ for iron alloys with Mn, Cr, V and W taken after annealing above the recrystallization temperature are also reported. 相似文献
52.
The problem of determining the longitudinal contour of a slender, axisymmetric body in hypersonic flow which has minimum drag is considered. The pressure distribution is assumed to be Newtonian, while the skin-friction distribution is for laminar flow and depends on body geometry. This investigation is conducted with the method of steepest descent, whose feasiblity is demonstrated by solving minimum drag problems having known analytical solutions. 相似文献
53.
William Squire 《Applied Scientific Research》1960,9(1):393-410
Summary A general theory of turbulent flow is applied to incompressible plane Couette flow. It is found that a unique formulation
is not obtained because of a singularity in the equations and problems relating to the boundary conditions. Solutions are
obtained for several different assumptions. The characteristic feature is a square root velocity profile for high Reynolds
numbers. The logarithmic law is obtained as a divergent approximation. There are discrepancies in the available experimental
data; one set agreeing with the square root form, and a second set with the logarithmic form. 相似文献
54.
Jarrad M. Altimari Joshua P. Delaney Linden Servinis Jennifer S. Squire Megan T. Thornton Simren K. Khosa Benjamin M. Long Mark D. Johnstone Cassandra L. Fleming Frederick M. Pfeffer Shane M. Hickey Matthew P. Wride Trent D. Ashton Bronwyn L. Fox Nolene Byrne Luke C. Henderson 《Tetrahedron letters》2012,53(16):2035-2039
Using microwave irradiation and protic ionic liquids (pIL) as co-solvent and catalyst for the synthesis of several diphenylmethyl ethers was achieved. The desired ethers were isolated simply by filtration through a silica plug to remove the pIL and proceeded in high yields (60–98%). These reactions were extremely rapid (10–30 min) and occurred under mild conditions (80 °C). This protocol was also successfully applied to the synthesis of thioethers. 相似文献
55.
The elution parameters of large enzymes, viruses, ribosomes and other “supramolecular” structures are studied using the preparative TSK G5000 PW type column. The pigmented protein, chlorocruorin, isolated from the sea worm Potamilla leptochaeta, was found to serve as an excellent high-molecular-weight marker for size exclusion liquid chromatography. This is due to its high degree of molecular stability and a molecular weight, found to be 2.9·106 by sedimentation velocity analysis, which is located in a zone formed between viruses and enzymes that is largely devoid of macromolecular markers. Calibration constants for this chromatography column are found for both molecular weight and molecular radii. The data found for hydrodynamic molecular radii are further extended to non-globular, swollen macromolecules, such as polysaccharides, using dextran fractions sized by alcohol precipitation. 相似文献
56.
Faulkner S Carrié MC Pope SJ Squire J Beeby A Sammes PG 《Dalton transactions (Cambridge, England : 2003)》2004,(9):1405-1409
Ytterbium and neodymium have been shown to exhibit sensitised emission following excitation of pyrene chromophores. Sensitised emission is demonstrated in self-assembled complexes and in azamacrocycle derivatives bearing pendent pyrene groups. Energy transfer in these systems is dependent on the nature of the link between the ligand and the complex. 相似文献
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59.
Analysis of natural gas by gas chromatography reduction of correlated uncertainties by normalisation
Brown AS Milton MJ Cowper CJ Squire GD Bremser W Branch RW 《Journal of chromatography. A》2004,1040(2):215-225
The results of gas chromatographic analysis of natural gas mixtures reveal strong correlations (Pearson correlation coefficient of >0.96) between the uncertainty of each component and variations in the ambient pressure. Although correction for ambient pressure variations can reduce this variability, normalisation of the results of each analysis using the assumption that the sum of all component amount fractions is unity provides significantly greater reductions in the uncertainty of each measured component. We show that the uncertainty in normalised components can be estimated approximately using the correlation coefficient as a measure of the correlation present in the measurements, or exactly using a full calculation of the variance/covariance (V/C) structure of the data. 相似文献
60.
Booker SJ 《Chemistry & biology》2004,11(1):10-12
Lipoic acid is almost universally required for aerobic metabolism. However, the mechanism for its synthesis and incorporation into proteins has remained elusive. A groundbreaking study published in the December issue of Chemistry & Biology uncovers critical features of the lipoic acid biosynthetic pathway. 相似文献