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71.
J. Lowe S.H. Chew J.M. Nelson C.E. Waltham G.J. Pyle G.T.A. Squier S. Baird C.J. Batty P. Sharman P. Bird A.S. Clough K.R. Parker 《Nuclear Physics B》1982,209(1):16-28
The reaction K?p → Λγ, produced by K? stopping in a liquid hydrogen target, has been studied using a NaI(Tl) gamma-ray spectrometer. The branching ratio is based on 1355 events assigned to this branch. This is in conflict with a previous experiment, but agrees with one of the two published calculations, when recent values for the coupling constants and scattering amplitudes are used. 相似文献
72.
The compound [HNMe2Ph][NpB(C6F5)3](Np =(CH3)3CCH2) reacts with dimethylzirconocenes to give active propylene polymerization catalysts which are significantly more active and give higher molecular weight polypropylene than do the catalysts obtained using B(C6F5)3; the [NpB(C6F5)3]- anion is for steric reasons more weakly coordinating than is [MeB(C6F5)3]-. 相似文献
73.
R. Kloch P. E. G. Baird M. G. Boshier M. J. Macpherson C. W. P. Palmer D. N. Stacey V. Stacey 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1987,6(4):315-317
We have measured isotope shifts in λ326.1 nm of CdI using a pressure-scanned interferometer. The results are, in GHz: 116–106, ?2.222 (30); 113–108, ?1.052(10); 111–110, ?0.049 (12); 111–106, ?1.048 (10). Results for stable isotopes in λ326.1 nm are needed in the interpretation of existing measurements on radioactive cadmium isotopes. The new data are more precise than early atomic beam measurements but are reasonably consistent with them. 相似文献
74.
Aaron P.R. Eberle Gregorio M. Vélez-García Donald G. Baird Peter Wapperom 《ournal of non Newtonian Fluid Mechanics》2010,165(3-4):110-119
The common approach for simulating the evolution of fiber orientation during flow in concentrated suspensions is to use an empirically modified form of Jeffery's equation referred to as the Folgar–Tucker (F-T) model. Direct measurements of fiber orientation were performed in the startup of shear flow for a 30 wt% short glass fiber-filled polybutylene terephthalate (PBT-30); a matrix that behaves similar to a Newtonian fluid. Comparison between predictions based on the F-T model and the experimental fiber orientation show that the model over predicts the rate of fiber reorientation. Rheological measurements of the stress growth functions show that the stress overshoot phenomenon approaches a steady state at a similar strain as the fiber microstructure, at roughly 50 units. However, fiber orientation measurements suggest that a steady state is not reached as the fiber orientation continues to slowly evolve, even up to 200 strain units. The addition of a “slip” parameter to the F-T model improved the model predictions of the fiber orientation and rheological stress growth functions. 相似文献
75.
Francoise Sauriol Dr. Elizabeth Wong Angela M. H. Leung Irja Elliott Donaghue Michael C. Baird Prof. Tebikie Wondimagegn Dr. Tom Ziegler Prof. 《Angewandte Chemie (International ed. in English)》2009,48(18):3342-3345
Caught in the act : An alkyl alkene ZrIV complex (see picture; Cp=C5H5) has been synthesized and characterized for the first time. The alkene bonding mode is highly asymmetric, and C2 is quite carbocationic. There is also evidence for rotation about the C1? C2 bond. This extremely unusual complex provides an exemplar of previously unknown intermediates in Ziegler–Natta and carbocationic polymerization reactions of alkenes.
76.
This paper chronicles the conceptual development, proof of principle experiments, and recent advances in the palladium-catalyzed cross-coupling reactions of the conjugate bases of organosilanols. The discovery that led to the design and refinement of this process represents a classical illustration of how mechanistic studies can provide a fertile ground for the invention of new reactions. On the basis of a working hypothesis (which ultimately proved to be incorrect) and the desire to effect silicon-based cross-coupling without the agency of fluoride activation, a mild and practical palladium-catalyzed cross-coupling of alkenyl-, aryl-, and heteroaryl silanolates has been developed. The mechanistic underpinnings, methodological extensions, and the successful applications of this technology to the synthesis of complex molecules are described. 相似文献
77.
Leland Rosenberger Ronald Baird Erik McCullen Gregory Auner Gina Shreve 《Surface and interface analysis : SIA》2008,40(9):1254-1261
Ten samples of crystalline aluminum nitride (AlN) film were deposited on sapphire and silicon substrates by a plasma source molecular beam method. The samples were analyzed using X‐ray photoelectron spectroscopy (XPS) depth profiling and high‐resolution X‐ray diffraction. Oxygen levels were observed to decrease exponentially from the surface into the bulk film. Aluminum, nitrogen and oxygen peaks were fitted with subpeaks in a consistent manner and the subpeaks were assigned to chemical states. AlN subpeaks were observed at 73.5 eV for Al2p and 396.4 eV for N1s. An N1s subpeak at 395.0 eV was assigned to N? N defects. No direct N? O bonds are assigned; rather it is proposed that an N? Al? O bond sequence is the source of higher binding energy N1s subpeaks. The observations in this study support a model in which oxygen is bound only to aluminum in the form of Al? O octahedral complexes dispersed or clustered throughout the main AlN matrix or as Al? O bonds on the crystal grain boundaries. The data also suggest that the AlN lattice parameters are related to oxygen content, since the c‐axis is observed to increase with increasing oxygen content. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
78.
V. M. Boitsov R. R. Kostikov A. P. Molchanov A. V. Stepakov M. S. Baird 《Russian Journal of Organic Chemistry》2004,40(12):1760-1763
The synthesis and dehydrohalogenation of diethyl halocyclopropane-1,1-dicarboxylates prepared from diethyl ethylidene- and benzylidenemalonates are described.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1811–1814.Original Russian Text Copyright © 2004 by Boitsov, Kostikov, Molchanov, Stepakov, Baird. 相似文献
79.
Cameron BR Darkes MC Baird IR Skerlj RT Santucci ZL Fricker SP 《Inorganic chemistry》2003,42(13):4102-4108
The preparation of a series of [Ru(III)(tacn)(eta(2)-dtc)(eta(1)-dtc)][PF(6)] (tacn = 1,4,7-triazacyclononane; dtc = dimethyldithiocarbamate, diethyldithiocarbamate, pyrrolidinedithiocarbamate, l-prolinedithiocarbamate, l-prolinemethyl ester dithiocarbamate, l-N-methylisoleucinedithiocarbamate) complexes, 5-11, is described. Complex 5 reacts with NO to form the ruthenium nitrosyl complex 12. A series of [Ru(III)(tacn)(pyc)Cl][PF(6)] (pyc = 2-pyridinecarboxylic acid, 2,4- and 2,6-pyridinecarboxylic acid) complexes, 14-16, were prepared along with [Ru(III)(tacn)(mida)][PF(6)] (mida = N-methyliminodiacetic acid), 13, and [Ru(III)(Hnota)Cl], 17, (Hnota = 1-acetic acid-4,7-bismethylcarboxylate-1,4,7-triazacyclononane). Complexes 5-17 were evaluated for use as NO scavengers in an in vitro assay using RAW264 murine macrophage cells. [Ru(III)(tacn)(eta(2)-dtc)(eta(1)-dtc)][PF(6)] complexes 5-11 are very efficient NO scavengers in this assay. 相似文献
80.
Sean W. Ewart Michelle A. Parent Michael C. Baird 《Journal of polymer science. Part A, Polymer chemistry》1999,37(23):4386-4389
Polymerization of propylene by Cp*TiMe2(μ-Me)B(C6F5)3 in the presence of increasing partial pressures of H2 results in ever decreasing polymer molecular weights, which is consistent with the hydrogenolytic chain transfer processes involving metal–polymer bonds in many heterogeneous and homogeneous systems. However, catalytic activities are not significantly increased as the extent of hydrogenolysis increases, unlike metallocene catalyst systems in which the H2 reacts primarily with dormant catalytic sites containing propylene 2,1-insertion products. It was shown previously that monocyclopentadienyl systems do not become seriously deactivated following 2,1 insertions, and thus hydrogenolysis does not result in enhanced activities. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4386–4389, 1999 相似文献