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61.
Mantsinen MJ Mayoral ML Kiptily VG Sharapov SE Alper B Bickley A de Baar M Eriksson LG Gondhalekar A Hellsten T Lawson K Nguyen F Noterdaeme JM Righi E Tuccillo AA Zerbini M 《Physical review letters》2002,88(10):105002
Third-harmonic ion-cyclotron-resonance heating of 4He-beam ions has produced for the first time on the JET tokamak high-energy populations of 4He ions to simulate 3.5 MeV fusion-born alpha (alpha) particles. Acceleration of 4He ions to the MeV energy range is confirmed by gamma-ray emission from the nuclear reaction 9Be(alpha,ngamma) 12C and excitation of Alfvén eigenmodes. Concomitant electron heating and sawtooth stabilization are observed. The scheme could be used in next-step tokamaks to gain information on trapped alpha particles and to test alpha diagnostics in the early nonactivated phase of operation. 相似文献
62.
Raja Dey Sandhya Roychowdhury P. Roychowdhury L. Righi 《Journal of chemical crystallography》1999,29(12):1271-1275
Synthetic steroid de-oxy corticosterone (4-pregnen-21-ol-3,20-dione) crystallizes in the monoclinic space group P21, with a = 11.706(2); b = 11.171(3), c = 13.966(3) Å, and = 100.94(2)°, Z = 4. Ring A tends to acquire the conformation of a half-boat, rings B and C are in the chair configuration, and ring D is a 13, 14-half-chair. The ring junctions B/C and C/D are both trans, whereas the ring junction A/B is quasi-trans. The molecule as a whole is slightly convex toward the -side, with an angle of 16.01(0.36)° between the C10--C19 and C13--C18 vectors. Molecular packing and stacking interactions play the major role in structural association. Cohesion of the crystal is due to van der Waals interactions. 相似文献
63.
Molybdenum dithiocarbamates (MoDTCs) are lubricant additives very efficient in reducing the friction of steel, and they are used in a number of industrial applications. The functionality of these additives is ruled by the chemical interactions occurring at the buried sliding interface, which are of key importance for the improvement of the lubrication performance. Yet, these tribochemical processes are very difficult to monitor in real time. Ab initio molecular dynamics simulations are the ideal tool to shed light on such a complicated reactivity. In this work, we perform ab initio simulations, both in static and tribological conditions, to understand the effect of surface oxidation on the tribochemical reactivity of MoDTC, and we find that when the surfaces are covered by oxygen, the first dissociative steps of the additives are significantly hindered. Our preliminary tribological tests on oxidized steel discs support these results. Bare metallic surfaces are necessary for a stable adsorption of the additives, their quick decomposition, and the formation of a durable MoS2 tribolayer. This work demonstrates the importance of the catalytic role of the substrate and confirms the full capability of the computational protocol in the pursuit of materials and compounds more efficient in reducing friction. 相似文献
64.
Righi Michele Moretti Giacomo Forehand David Agostini Lorenzo Vertechy Rocco Fontana Marco 《Nonlinear dynamics》2021,105(4):2861-2876
Nonlinear Dynamics - Dielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable... 相似文献
65.
An unprecedented one-pot reaction that allows the synthesis of diprotected amino alcohols from unprotected vinyl aziridines is reported. The results demonstrate the possibility to use various acyl chlorides in order to obtain differently functionalised fragments. Mechanistic insights are given. 相似文献
66.
Rosini G Borzatta V Boschi F Candido G Marotta E Righi P 《Chemical communications (Cambridge, England)》2007,(26):2717-2719
The occurrence of p(1),n(1) salt when accompanied by substrate self-association can have profound effects on enantiomer separation processes of non-racemic mixtures, impeding the complete recovery of the major enantiomer through formation of an inescapable racemate cage. 相似文献
67.
Improved procedure for the deracemization of α-methyl dihydrocinnamic aldehydes (2-methyl-3-phenylpropanals) with L-(+)-tartaric acid salt of (S)-enantiomer of Betti's base, is presented. The method enabled the transacetalization of N,O-ketal (R)-enantiomer of Betti's base with various aldehydes. 相似文献
68.
New first- and high-order centred methods for conservation lawsare presented. Convenient TVD conditions for constructing centredTVD schemes are then formulated and some useful results areproved. Two families of centred TVD schemes are constructedand extended to nonlinear systems. Some numerical results arealso presented. 相似文献
69.
Giuliana Righi Livia Salvati ManniPaolo Bovicelli Romina Pelagalli 《Tetrahedron letters》2011,52(30):3895-3896
A new, simple, and mild regio-and stereocontrolled azidolysis of vinylepoxides with TMSN3/BF3 system is reported. The method appears of general value and works very well particularly in the presence of electron-poor olefins, regardless of the size of substituents on the heterocyclic ring. 相似文献
70.
D. Lpez E. A. Jagla E. F. Righi E. Osquiguil G. Nieva E. Morr F. de la Cruz C. A. Balseiro 《Physica C: Superconductivity and its Applications》1996,260(3-4):211-216
Transport measurements in the mixed state of oxygen-deficient YBa2Cu3O7−δ single crystals using the flux transformer configuration show that the flux liquid changes with increasing anisotropy from strongly correlated to uncorrelated in the field direction. For intermediate coupling, the current inducing loss of vortex correlation has a maximum near the irreversibility temperature. Thus, an effective softening of vortex lines with decreasing temperature is detected. We propose a simple model that accounts for this behavior by including the effects of the pinning potential on the dynamics of vortices. 相似文献