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61.
We establish a decomposability criterion for linear sheaves on ℙ
n
. Applying it to instanton bundles, we show, in particular, that every rank 2n instanton bundle of charge 1 on ℙ
n
is decomposable. Moreover, we provide an example of an indecomposable instanton bundle of rank 2n − 1 and charge 1, thus showing that our criterion is sharp. 相似文献
62.
Marcos Jardim 《Bulletin of the Brazilian Mathematical Society》2007,38(4):649-659
Using monads, we construct a large class of stable bundles of rank 2 and 3 on 3-fold hypersurfaces, and study the set of all
possible Chern classes of stable vector bundles. 相似文献
63.
64.
Rosana M. Alberici Maria Anita Mendes Wilson F. Jardim Marcos N. Eberlin 《Journal of the American Society for Mass Spectrometry》1998,9(12):1321-1327
On-line Mass Spectrometry and MS2 are applied to monitor and identify the by-products and total mineralization products of TiO2/UV photocatalytic degradation of four chlorinated volatile organic compounds (VOCs): trichloroethylene (TCE), tetrachloroethylene (TeCE), chloroform, and dichloromethane. Selected multiple ion mass spectrometry monitoring using characteristic 70 eV electron ionization ionic fragments monitors in real time the destruction of the starting VOC and the formation of by-products, i.e., the degrees of VOC mineralization, as a function of the flow and relative humidity of the carrier gas (synthetic air). Several by-products were detected: phosgene for TCE, TeCE, and chloroform; dichloroacetyl chloride for TCE; and trichloroacetyl chloride for TeCE. Cl2 and CO2 were also detected as final mineralization products of the four chlorinated VOCs. Structural characterization of by-products was accomplished via MS2 collision-induced dissociation of molecular ions or characteristic ionic fragments. 相似文献
65.
用从头算方法在B3LYP/ 6 31G 水平上对亚胺膦R3PNH(R =CH3,Cl)进行了理论计算研究。结果表明这两种亚胺膦的极性 ,P -N键性质及分子轨道存在明显差异 ,亚胺膦 (CH3) 3P =NH及其P -N键的极性很强 ,而Cl3P =NH的极性则较弱。与Cl3P =NH相比 (CH3) 3P =NH可能是较好的类Wittig反应试剂。 相似文献
66.
Israel D. Souza Lidervan P. Melo Isabel C.S.F. Jardim Juliana C.S. Monteiro Ana Marcia S. Nakano Maria Eugênia C. Queiroz 《Analytica chimica acta》2016
A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL−1 (LLOQ) to 400 ng mL−1 with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from −1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective. 相似文献
67.
We show that if 𝒜 is an abelian category satisfying certain mild conditions, then one can introduce the concept of a moduli space of (semi)stable objects which has the structure of a projective algebraic variety. This idea is applied to several important abelian categories in representation theory, like highest weight categories. 相似文献
68.
Gui-Qiang G.Chen School of Mathematical Sciences Fudan University Shanghai China Mathematical Institute University of Oxford - St Giles Oxford OX LB UK 《数学物理学报(B辑英文版)》2010,30(2):391-427
We are concerned with the derivation and analysis of one-dimensional hyperbolic systems of conservation laws modelling fluid flows such as the blood flow through compliant axisymmetric vessels.Early models derived are nonconservative and/or nonhomogeneous with measure source terms,which are endowed with infinitely many Riemann solutions for some Riemann data.In this paper,we derive a one-dimensional hyperbolic system that is conservative and homogeneous.Moreover,there exists a unique global Riemann solution for the Riemann problem for two vessels with arbitrarily large Riemann data,under a natural stability entropy criterion.The Riemann solutions may consist of four waves for some cases.The system can also be written as a 3×3 system for which strict hyperbolicity fails and the standing waves can be regarded as the contact discontinuities corresponding to the second family with zero eigenvalue. 相似文献
69.
Marcos Jardim 《代数通讯》2013,41(6):2249-2270
We generalize the theory of Horrocks monads to ACM varieties, and use the generalization to establish a cohomological characterization of linear and Steiner bundles on projective space and on quadric hypersurfaces. We also characterize Steiner bundles on the Grassmannian G(1, 4) of lines in ?4. Finally, we study linear resolutions of bundles on ACM varieties, and characterize linear homological dimension on quadric hypersurfaces. 相似文献
70.
Paula M. Jardim Lidija Mancic Bojan A. Marinkovic Olivera Milosevic Fernando Rizzo 《Central European Journal of Chemistry》2011,9(3):415-421
Nax−yHyTi2−xFexO4·nH2O nanosheets with lepidocrocite-like layered structure were produced through alkaline hydrothermal treatment at very low temperatures
(130°C) from ilmenite sand. The crystal structure, morphology and optical properties were investigated by X-Ray diffraction,
transmission electron microscopy, selected area electron diffraction, energy dispersive spectroscopy and UV-Vis spectroscopy.
The product shows leaf-like nanosheet morphology with thickness <30 nm and lengths <1 μm. Three lepidocrocite-like titanates
(Imm2 space group) with similar a and c lattice parameters but different interlayer distances (b/2) were identified. This
appears to be the first preparation of lepidocrocite-like layered nanosheets by a simple, energy efficient (low temperature)
and low cost (starting from mineral sand) procedure. 相似文献