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1.
Apurba Bhattacharya Nitin C. Patel Michael Peddicord Luca Parlanti John A. Grosso 《Tetrahedron letters》2006,47(30):5341-5343
An efficient, one-pot, phase transfer N-amination technology was developed. The protocol utilizes chloramine, an inexpensive and safe electrophilic aminating agent potentially viable for commercial manufacturing. 相似文献
2.
Luca Lambertini Raimondello Orsini 《Central European Journal of Operations Research》2007,15(1):105-117
We reconsider the role of network externalities in a dynamic spatial monopoly where the firm must invest in order to accumulate
capacity, while consumers may have either linear or quadratic preferences. We (1) characterise saddle point equilibria, (2)
prove that the extent of market coverage is increasing in the network effect and (3) unlike the existing static literature
on the same problem, the monopolist may not make introductory price offers. Then, we briefly deal with the socially optimal
solution, showing that, in general, a planner would serve more consumers than a profit-seeking monopolist.
相似文献
3.
Blundell Tom L. Bolanos-Garcia Victor Chirgadze Dimitri Y. Harmer Nicholas J. Lo Thomas Pellegrini Luca Sibanda B. Lynn 《Structural chemistry》2002,13(3-4):405-412
Signaling in living systems needs to achieve high specificity, to be reversible, and to achieve high signal to noise. Signaling mediated by multiprotein systems has evolved that avoids the requirement for high-affinity binary complexes that would be difficult to reverse and which, in the overcrowded cell, would lead to excessive noise in the system. Symmetrical structures are only occasionally formed. When they are, it is principally to colocate components, for example, the tyrosyl kinases of growth factors, where dimers form. Symmetry is, however, often broken, presumably to create more sensitivity and specificity in the signaling system by assembling other components, into higher-order multiprotein systems. The binding of a single heparin to two 1:1 FGF:FGFR complexes is an example, as is the binding of a single ligase to the Xrcc4 dimer, perhaps so creating a further DNA-binding site. 相似文献
4.
In this work we consider computing and continuing connecting orbits in parameter dependent dynamical systems. We give details
of algorithms for computing connections between equilibria and periodic orbits, and between periodic orbits. The theoretical
foundation for these techniques is given by the seminal work of Beyn in 1994, “On well-posed problems for connecting orbits
in dynamical systems”, where a numerical technique is also proposed. Our algorithms consist of splitting the computation of
the connection from that of the periodic orbit(s). To set up appropriate boundary conditions, we follow the algorithmic approach
used by Demmel, Dieci, and Friedman, for the case of connecting orbits between equilibria, and we construct and exploit the
smooth block Schur decomposition of the monodromy matrices associated to the periodic orbits. Numerical examples illustrate
the performance of the algorithms.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Image potential resonances on the Sn/Ge(1 1 1) α-phase are investigated by two closely related methods: specular electron reflection and so-called selective electron scattering. Electrons from image resonances are detected on this surface at 120 and 300 K, i.e. below and above the phase transition at about 200 K. The dispersion of the image resonances reveals at these two temperatures equivalent effective electron masses, which are characteristic for this type of electronic surface states. The results of the two methods are consistent according to the similarity of the scattering processes. Changes in the loss peak intensity with the annealing temperature are assigned to the surface quality and are reflected by characteristic photoemission intensities. 相似文献
6.
7.
Marco Caliari Marco Vianello Luca Bergamaschi 《Journal of Computational and Applied Mathematics》2007,210(1-2):56-63
We implement a second-order exponential integrator for semidiscretized advection–diffusion–reaction equations, obtained by coupling exponential-like Euler and Midpoint integrators, and computing the relevant matrix exponentials by polynomial interpolation at Leja points. Numerical tests on 2D models discretized in space by finite differences or finite elements, show that the Leja–Euler–Midpoint (LEM) exponential integrator can be up to 5 times faster than a classical second-order implicit solver. 相似文献
8.
9.
Beverina L Abbotto A Landenna M Cerminara M Tubino R Meinardi F Bradamante S Pagani GA 《Organic letters》2005,7(19):4257-4260
[graph: see text] Condensation of squaric acid with a number of differently substituted 2-pyrrolyl derivatives afforded three new classes of squaraines. Their sharp and intense absorption bands in the biological window (700-900 nm), inherent singlet oxygen generation capabilities, together with proper functionalization allowing good water solubility make them suitable candidates as new non-porphyrinic singlet oxygen photosensitizers for photodynamic therapy (PDT). 相似文献
10.
V. Nastro D. Vuono M. Guzzo G. Niceforo I. Bruno P. De
Luca 《Journal of Thermal Analysis and Calorimetry》2006,84(1):181-184
The aim of this paper is to characterize some raw
materials used for ceramics material production. Five samples of clay have
been analyzed. It has been carried out a patterned sampling in a quarry in
Rosarno (South Italy).
Chemical-physical
properties on clay samples are determined. Test pieces have been prepared
and physical properties after firing are determined by DSC thermal analysis,
XRD analysis and X-ray fluorescence. It is important to note the high amount
of Fe2O3. The mixture principally
contains quartz, illite and oligoclase. It has been observed the colour and
the shape after firing: predominant colour is red. In this case the clay has
been used in mixtures covered with glazes. The colour of internal clay is
hidden by opaque of glazes. The analysed raw materials can be used in a slip
for single fired red tiles. The A2sp clay produces best ceramics at 1000°C. 相似文献