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141.
S. W. Annie Bligh Nick Choi Donovan St.C. Green Harry R. Hudson Catherine M. McGrath Mary McPartlin 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract α-Hydroxyiminophosphonic acid derivatives are widely known not only as intermediates in the synthesis of the important aminophosphonic acids,1,2 but also as phosphorylating agents,3 potential metalloenzyme inhibitors,4 and as compounds having fungicidal activity.5 In this work the scope of these compounds has been extended considerably by the synthesis of a number of novel dialkyl derivatives. Novel lanthanide (LaIII, PrIII, NdIII, GdIII and DyIII) and transition metal (CoII and NiIII) complexes of dialkyl α-hydroxyiminophosphonates (RO)2P(O)C(R')N(OH) where R = Et. Pri and R′ = Me, Et have been prepared and the NMR shift properties of the PrIII complex (R = Et; R′ = Et) indicate the potential of these compounds as NMR shift reagents for the analysis of geometric isomers.6,7 X-ray crystal structure analysis of [Ni(L1)2C12] (L1: R = Et; R′ = Et) shows a distorted cis octahedral coordination at the nickel atom giving two symmetry related diethyl-(E)-α-hydroxyiminopropanephosphonate ligands and two chlorine donors, and those of [Pr(L2)3Cl3] and [Nd(L2)2(NO3)3(H2O)] (L2: R = Pri; R′ = Et) show nine-coordination geometries with asymmetric bidentate and monodentate L2 bonding respectively. Thus the metal complexes show unusual coordination ambivalence, changing from symmetrically bidentate to asymmetrically bidentate and then to monodentate bonding modes, to accommodate the different steric requirements of the coordinating anions in facilitating neutral complex formation. 相似文献
142.
143.
Soft X-ray resonant magnetic scattering (SXRMS) has been used to investigate the microscopic magnetization reversal behavior of complex magnetic systems. SXRMS is a unique technique, providing chemical, spatial and magnetic sensitivity, which is not affected by external magnetic fields. The study of two selected thin magnetic heterostructures is presented, amorphous rare-earth transition metal alloys and perpendicular exchange coupled antiferromagnetic/ferromagnetic films. In the first system, the internal structure of magnetic stripe domains on nanometer length scales is obtained by measuring bi-dimensional (2D) scattering images. In the second system, the element specificity is exploited to identify the role of the uncompensated spins in the antiferromagnetic layer on the exchange coupling phenomena. Future trends are also discussed. 相似文献
144.
Nick Gurski Niles Johnson Angélica M. Osorno 《Journal of Pure and Applied Algebra》2019,223(10):4348-4383
We prove that the homotopy theory of Picard 2-categories is equivalent to that of stable 2-types. 相似文献
145.
Nick Brettell Jake Horsfield Andrea Munaro Giacomo Paesani Daniël Paulusma 《Journal of Graph Theory》2022,99(1):117-151
A large number of -hard graph problems are solvable in time when parameterized by some width parameter. Hence, when solving problems on special graph classes, it is helpful to know if the graph class under consideration has bounded width. In this paper we consider maximum-induced matching width (mim-width), a particularly general width parameter that has a number of algorithmic applications whenever a decomposition is “quickly computable” for the graph class under consideration. We start by extending the toolkit for proving (un)boundedness of mim-width of graph classes. By combining our new techniques with known ones we then initiate a systematic study into bounding mim-width from the perspective of hereditary graph classes, and make a comparison with clique-width, a more restrictive width parameter that has been well studied. We prove that for a given graph , the class of -free graphs has bounded mim-width if and only if it has bounded clique-width. We show that the same is not true for -free graphs. We identify several general classes of -free graphs having unbounded clique-width, but bounded mim-width; moreover, we show that a branch decomposition of constant mim-width can be found in polynomial time for these classes. Hence, these results have algorithmic implications: when the input is restricted to such a class of -free graphs, many problems become polynomial-time solvable, including classical problems, such as - Colouring and Independent Set , domination-type problems known as Locally Checkable Vertex Subset and Vertex Partitioning (LC-VSVP) problems, and distance versions of LC-VSVP problems, to name just a few. We also prove a number of new results showing that, for certain and , the class of -free graphs has unbounded mim-width. Boundedness of clique-width implies boundedness of mim-width. By combining our results with the known bounded cases for clique-width, we present summary theorems of the current state of the art for the boundedness of mim-width for -free graphs. In particular, we classify the mim-width of -free graphs for all pairs with . When and are connected graphs, we classify all pairs except for one remaining infinite family and a few isolated cases. 相似文献
146.
This review covers the activation, aggregation and degradation of white phosphorus by molecules containing reactive p-block centers. The chemistry has been divided into a number of reaction types and possible mechanisms are used to aid in the understanding of these reactions. 相似文献
147.
This article establishes sufficient conditions for a linear-in-time bound on the non-asymptotic variance for particle approximations of time-homogeneous Feynman–Kac formulae. These formulae appear in a wide variety of applications including option pricing in finance and risk sensitive control in engineering. In direct Monte Carlo approximation of these formulae, the non-asymptotic variance typically increases at an exponential rate in the time parameter. It is shown that a linear bound holds when a non-negative kernel, defined by the logarithmic potential function and Markov kernel which specify the Feynman–Kac model, satisfies a type of multiplicative drift condition and other regularity assumptions. Examples illustrate that these conditions are general and flexible enough to accommodate two rather extreme cases, which can occur in the context of a non-compact state space: (1) when the potential function is bounded above, not bounded below and the Markov kernel is not ergodic; and (2) when the potential function is not bounded above, but the Markov kernel itself satisfies a multiplicative drift condition. 相似文献
148.
149.
Gerald Tuskan Darrell West Harvey D. Bradshaw David Neale Mitch Sewell Nick Wheeler Bob Megraw Keith Jech Art Wiselogel Robert Evans Carolyn Elam Mark Davis Ron Dinus 《Applied biochemistry and biotechnology》1999,77(1-3):55-65
Two new high-through put techniques, computer tomography X-ray densitometry (CT scan) and pyrolysis molecular beam mass spectrometry
(pyMBMS), coupled with quantitative trait loci (QTL) analysis, were tested as a means to overcome the time and cost associated
with conventional characterization of biomass feedstock components. Applications of these two techniques were evaluated using
hybrid poplar for the CT scan and loblolly pine for the pyMBMS. Segregating progeny from hybrid poplar varied in specific
gravity, with individual mean estimates ranging from 0.21–0.41. Progeny from loblolly pine varied in lignin, α cellulose,
and mannan contents, with individual mean estimates of lignin content ranging from 28.7–33.1%, α cellulose content from 28.8–43.5%
and mannan content from 4.2–10.1%. QTL analysis of the loblolly pine data suggested that eleven QTLs were associated with
individual feedstock characteristics and that two QTLs for several feedstock components were linked to the same position on
the loblolly pine genetic map. Each QTL individually accounted for 7–13% of the total phenotypic variation in associated loblolly
pine feedstock components. 相似文献
150.
Nick Serpone Satoshi Horikoshi Alexei V. Emeline 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2010,11(2-3):114-131
This review article focuses, albeit non-exhaustively, on the influence of microwave radiation on photoassisted processes often referred to as Advanced Oxidation Processes. In particular, we describe and illustrate the possible advantages of microwaves in TiO2-assisted photodegradations and photomineralizations of various organic pollutants such as herbicides and endocrine disruptors, among others. Described are also various reactor configurations involving UV/visible radiation and microwaves, with the former being supplied either by traditional Hg lamps or alternatively by electrodeless lamps activated by microwaves. To place the use of microwaves on processes occurring in aqueous TiO2 dispersions in perspective regarding environmental applications, we first introduce the various sources of pollutants and subsequently describe in brief the various advanced oxidation processes such as UV/peroxidation, UV/ozonation and the photo-Fenton process(es) in addition to direct photolysis either by sunlight or by artificial light sources. 相似文献