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31.
Lodovico Lunazzi Claudio Magagnoli Maurizio Guerra Dante Macciantelli 《Tetrahedron letters》1979,20(32):3031-3032
Low temperatures C-13 NMR spectra allowed the determination of the rotational barrier of N-methyl aniline in solution. The shifts of the anisochronous ortho and meta carbons were assigned by calculations. 相似文献
32.
33.
Bencini A Beni A Costantino F Dei A Gatteschi D Sorace L 《Dalton transactions (Cambridge, England : 2003)》2006,(5):722-729
[Co(Me(4)cyclam)(tropolonate)](PF(6)) was synthesised and structurally characterised. Its electronic and W-band EPR spectra have been analysed by means of the angular overlap calculation of the Spin Hamiltonian parameters that provided also a satisfactory reproduction of the temperature dependence of the magnetic susceptibility. The present results can be interpreted assuming a pseudo-octahedral character for the Co(II) center. This prompted us to reconsider the model formerly used for the analysis of the magnetic coupling between hs-Co(II) and the paramagnetic o-semiquinonate ligand in the corresponding derivatives [Co(Me(4)cyclam)(PhenSQ)](PF(6)) and [Co(Me(4)cyclam)(DTBSQ)](PF(6)). These results indicate that the effect of the magnetic coupling is active only below 50 K and that a more refined model of exchange coupling between Co(II) and semiquinonato ligands is needed to quantitatively analyze the magnetic behaviour of this class of systems. 相似文献
34.
Quantitative X‐ray fluorescence (XRF) measurements have been conducted on naturally lead‐contaminated samples. The calibration procedure using the ratio of fluorescence to Compton scattered radiation was investigated using Monte Carlo simulation. Experimental results with low‐energy photons (14 keV) and simulations show a very good linearity of the fluorescence to Compton ratio as a function of metal concentration. Lead (Pb), iron (Fe) and zinc (Zn) are measured in samples of Phaseolus vulgaris (bean seeds) that have been grown using a nutritive solution with different Pb dopings. Naturally contaminated samples are thus obtained. The calibration must be done for fixed conditions of X‐ray energy and scattering angle, while X‐ray beam intensity and detector to sample distance can change from one sample to another. Simulation allows to evaluate the matrix effect on the calibration curve, and shows that linearity is preserved even in the presence of other heavy elements in the fluorescence spectrum. However, calibration must be done using samples with similar matrix as it affects the slope of the curve. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
35.
Erwin Hernández Dante Kalise Enrique Otárola 《Computational Optimization and Applications》2010,47(1):161-178
The aim of this work is to obtain optimal-order error estimates for the LQR (Linear-quadratic regulator) problem in a strongly
damped 1-D wave equation. We consider a finite element discretization of the system dynamics and a control law constant in
the spatial dimension, which is studied in both point and distributed case. To solve the LQR problem, we seek a feedback control
which depends on the solution of an algebraic Riccati equation. Optimal error estimates are proved in the framework of the
approximation theory for control of infinite-dimensional systems. Finally, numerical results are presented to illustrate that
the optimal rates of convergence are achieved. 相似文献
36.
R. Dante DeBlassie 《Stochastics An International Journal of Probability and Stochastic Processes》2013,85(4):181-203
Consider a scale invariant diffusion whose state space is a closed cone in R d , minus the vertex. Then the process is either recurrent, transient to ∞ or transient to the vertex of the cone. In the latter case, the diffusion has finite lifetime (a.s.) and converges to the vertex at the lifetime. The Martin boundary consists of two points, and the corresponding minimal harmonic functions are of the form 1 and |x| α ψ(x/|x|). 相似文献
37.
Alberti A Benaglia M Guerra M Gulea M Macciantelli D Masson S 《Organic letters》2008,10(15):3327-3330
The direct EPR detection of thioacyl radicals has been reported only once, while thioacyl nitroxides remain an elusive species. We failed to detect the thioacyl radicals from two thioaldehydes and from phosphoryldithioformates but have obtained EPR evidence that thioacyl radicals react with 2-methyl-2-nitrosopropane to give thiocarbonyloxyaminyls rather than thioacyl nitroxides. The results of DFT calculations support this unexpected reactivity of thioacyls, while making questionable their previous EPR identification. 相似文献
38.
A heterogeneous PNA-based SERS method for DNA detection 总被引:1,自引:0,他引:1
Fabris L Dante M Braun G Lee SJ Reich NO Moskovits M Nguyen TQ Bazan GC 《Journal of the American Chemical Society》2007,129(19):6086-6087
39.
Cariati E Macchi R Roberto D Ugo R Galli S Casati N Macchi P Sironi A Bogani L Caneschi A Gatteschi D 《Journal of the American Chemical Society》2007,129(30):9410-9420
Mixed M(II)/M(III) metal oxalates, as "stripes" connected through strong hydrogen bonding by para-dimethylaminobenzaldeide (DAMBA) and water, form an organic-inorganic 2D network that enables segregation in layers of the cationic organic NLO-phore trans-4-(4-dimethylaminostyryl)-1-methylpyridinium, [DAMS+]. The crystalline hybrid materials obtained have the general formula [DAMS]4[M2M'(C2O4)6].2DAMBA.2H2O (M = Rh, Fe, Cr; M' = Mn, Zn), and their overall three-dimensional packing is non-centrosymmetric and polar, therefore suitable for second harmonic generation (SHG). All the compounds investigated are characterized by an exceptional SHG activity, due both to the large molecular quadratic hyperpolarizability of [DAMS+] and to the efficiency of the crystalline network which organizes [DAMS+] into head-to-tail arranged J-type aggregates. The tunability of the pairs of metal ions allows exploiting also the magnetic functionality of the materials. Examples containing antiferro-, ferro-, and ferri-magnetic interactions (mediated by oxalato bridges) are obtained by coupling proper M(III) ions (Fe, Cr, Rh) with M(II) (Mn, Zn). This shed light on the role of weak next-nearest-neighbor interactions and main nearest-neighbor couplings along "stripes" of mixed M(II)/M(III) metal oxalates of the organic-inorganic 2D network, thus suggesting that these hybrid materials may display isotropic 1D magnetic properties along the mixed M(II)/M(III) metal oxalates "stripes". 相似文献
40.
Alasino RV Bianco ID Vitali MS Zarzur JA Beltramo DM 《Macromolecular bioscience》2007,7(9-10):1132-1138
The antiviral effects of the cationic acrylate polymer E100 on a panel of lipid-enveloped viruses and the interactions involved are studied. The treatment of several common viruses with E100 induced a dose-dependent inhibition of the infectivity of viruses below the detection limit of the assays employed. Similarly, the treatment of human sera infected with HIV or HCV reduced virus RNA plasma levels to undetectable values. This implies that Eudragit E100 can interact with enveloped viruses, even in the presence of proteins, through a mechanism that is not reversed by titration of the positively charged groups of the polymer, opening the possibility to remove viral particles with the polymer as it is eliminated. 相似文献