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81.
Physical and chemical ion erosion surface interactions are observed for various elements and composite materials such as Si, B, C, TiB2, WCCo cermet, and stainless steel which have been bombarded by low energy (50–1800 eV) hydrogen ions. Extrapolations of hydrogen erosion yields to zero hydrogen ion energy indicate that compounds or elements which are capable of forming volatile compounds with hydrogen undergo selective removal from surface and near surface regions. Auger depth profiling indicates that carbon can be selectively removed from near surface regions of cemented carbides and carburized stainless steel. Similarly, boron can be selectively removed from TiB2. The results of this study may be extended to a variety of materials in which surface composition modifications are of interest. 相似文献
82.
This paper concerns the statistical properties of hyperbolic diffeomorphisms. We obtain a large deviation result with respect to slowly shrinking intervals for a large class of Hölder continuous functions. In case of time reversal symmetry, we obtain a corresponding version of the Fluctuation Theorem. 相似文献
83.
D Laffey C Hunka J A Sharp Z Zeng 《The Journal of the Operational Research Society》2009,60(3):411-418
Paid search is an important form of online advertisement. Clickthroughs from slots are bid for by advertisers. The process of formulating bids is a complex one involving bidders in competing against other advertisers in multiple auctions. It would be helpful in managing the bidding process if it were possible to determine the values placed on a clickthrough by different advertisers. The theory of two models for estimating advertiser values and associated parameters is presented. The models are applied to a set of data for searches on the term Personal Loans. The results of the model that fits the data better are evaluated. The utility of the model to practitioners is discussed. Some issues raised by the results about the role of bidding agents and the discriminatory power of Customer Relationship Management systems are considered. Ways to develop the preferred model are outlined. It is suggested that the model has implications for evaluating forecasting methods for use in paid search auctions. 相似文献
84.
1,4-Shifts of the carbon-bonded metal are observed on heating solutions of trans-bromo(dibenz[a,c]anthracen-9-yl)bis(triethylphosphine)platinum or trans-bromo(dibenz[a,c]anthracen-9-yl)bis(triethylphosphine)palladium. The shift does not occur from the cis isomer and is more rapid for the Pt complex. Solvent effects suggest polar species, while the absence of deuterium incorporation in the presence of D2O indicates nonacidic intermediates. 相似文献
85.
Schiffer JP Hoffman CR Kay BP Clark JA Deibel CM Freeman SJ Howard AM Mitchell AJ Parker PD Sharp DK Thomas JS 《Physical review letters》2012,108(2):022501
The quantitative consistency of nucleon transfer reactions as a probe of the occupancy of valence orbits in nuclei is tested. Neutron-adding, neutron-removal, and proton-adding transfer reactions were measured on the four stable even Ni isotopes, with particular attention to the cross section determinations. The data were analyzed consistently in terms of the distorted wave Born approximation to yield spectroscopic factors. Valence-orbit occupancies were extracted, utilizing the Macfarlane-French sum rules. The deduced occupancies are consistent with the changing number of valence neutrons, as are the vacancies for protons, both at the level of <5%. While there has been some debate regarding the true "observability" of spectroscopic factors, the present results indicate that empirically they yield self-consistent results. 相似文献
86.
Asymptotic Expansions for Closed Orbits in Homology Classes 总被引:3,自引:0,他引:3
In this paper, we study the behaviour of the counting function associated to the closed geodesics lying in a prescribed homology class on a compact negatively curved manifold. Our main result is an asymptotic expansion. We also obtain results in the wider context of periodic orbits of Anosov flows. 相似文献
87.
Thomas R. Sharp Kyle R. LeemanD.Eugene Bryant George J. Horan 《Tetrahedron letters》2003,44(8):1559-1561
Photostability challenge of ziprasidone in solution shows that the benzisothiazole moiety undergoes isomerization to the corresponding benzthiazole. A model compound, 3-piperazinyl-1,2-benzisothiazole, also undergoes this photoisomerization. Identification of the products has been confirmed by synthesis of the proposed molecules. 相似文献
88.
89.
Richard Sharp 《Geometriae Dedicata》2007,125(1):63-74
Let Γ be a convex co-compact group of isometries of a CAT(−1) space X and let Γ0 be a normal subgroup of Γ. We show that, provided Γ is a free group, a sufficient condition for Γ and Γ0 to have the same critical exponent is that Γ / Γ0 is amenable.
相似文献
90.