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71.
Ergun RE Malaspina DM Cairns IH Goldman MV Newman DL Robinson PA Eriksson S Bougeret JL Briand C Bale SD Cattell CA Kellogg PJ Kaiser ML 《Physical review letters》2008,101(5):051101
We show that observed spatial- and frequency-domain signatures of intense solar-wind Langmuir waves can be described as eigenmodes trapped in a parabolic density well. Measured solar-wind electric field spectra and waveforms are compared with 1D linear solutions and, in many cases, can be represented by 1-3 low-order eigenstates. To our knowledge, this report is the first observational confirmation of Langmuir eigenmodes in space. These results suggest that linear eigenmodes may be the starting point of the nonlinear evolution, critical for producing solar type II and type III radio bursts. 相似文献
72.
J. P. Briand P. Indelicato M. Tavernier O. Gorceix D. Liesen H. F. Beyer B. Liu A. Warczak J. P. Desclaux 《Zeitschrift für Physik A Hadrons and Nuclei》1984,318(1):1-5
Hydrogenlike and heliumliken=2→n=1 lines in Kr have been produced and studied for the first time. HydrogenlikeL y α lines have been observed and the fine structure interval has been determined. The absolute energy of the1P1,3P2,3P1 lines of heliumlike Kr have been measured and compared to Multiconfigurational Dirac-Fock Calculations. 相似文献
73.
The study of the radiation yields of free radical formation in deaerated dioxane solutions containing a fluorescent solute (PPO or PBD) or a chlorinated compound (CCl4 or CHCl3) shows that there are two possible mechanisms for energy transfer from superexcited states: transfer of the electronic excitation energy, and the ionc mechanism which involves the electrons formed by autoionization. We propose a kinetic scheme which agrees with experimental results. 相似文献
74.
Pantarotto D Briand JP Prato M Bianco A 《Chemical communications (Cambridge, England)》2004,(1):16-17
Functionalised carbon nanotubes are able to cross the cell membrane and to accumulate in the cytoplasm or reach the nucleus without being toxic for the cell up to 10 [micro sign]M. 相似文献
75.
J.P.Briand 《中国物理 C》2007,31(Z1):236-236
The ECR ion sources have mainly been used until now for injection of cyclotrons and a large number of these sources are presently in operation through the world.Most cyclotrons are used today for nuclear physics researches but an increasing number of these accelerators are now devoted to medical applications.The ECR ion sources have also been extensively used for producing low energy beams for academic researches in atomic and surface physics.These studies led to very encouraging results opening the way to industrial applications. In this talk some of the most promising applications of HCI beams will be reviewed.The development of these applications will require some important improvements of the ECR sources which will be discussed.A special emphasis will be given to the respective roles of ECR and EBIS ion sources in these industrial applications, and some economic and market considerations discussed. 相似文献
76.
Detonation initiation is investigated in aluminium/oxygen and aluminium/air mixtures. Critical conditions for initiation of
spherical detonations are examined in analogy with the criteria defined for gaseous mixtures, which correlate critical parameters
of detonation initiation to the characteristic size of the cellular structure. However, experimental data on the detonation
cell size in these two-phase mixtures are very scarce, on account of the difficulty to perform large-scale experiments. Therefore,
2D numerical simulations of the detonation cellular structure have been undertaken, with the same combustion model for Al/air
and Al/O2 mixtures. The cell size is found to be λ = 37.5 cm for a rich (r = 1.61) aluminium–air mixture, and λ = 7.5 cm for a stoichiometric aluminium-oxygen mixture, which is in reasonable agreement with available experimental data.
Calculations performed in large-scale configurations (up to 25 m in length and 1.5 m in lateral direction) suggest that the
critical initiation energy and predetonation radius for direct initiation of the unconfined detonation in the aluminium–air
mixture are, respectively, 10 kg of TNT and 8 m. Moreover, numerical simulations reveal that the structure of the detonation
wave behind the leading front is even more complicated than in pure gaseous mixtures, due to two-phase flow effects.
This paper is based on work that was presented at the 21st International Colloquium on the Dynamics of Explosions and Reactive
Systems, Poitiers, France, July 23–27, 2007. 相似文献
77.
78.
79.
Christine Hemmerlin Michel Marraud Didier Rognan Roland Graff Vincent Semetey Jean‐Paul Briand Gilles Guichard 《Helvetica chimica acta》2002,85(11):3692-3711
To further investigate the degree of structural homology between γ‐peptides A and N,N′‐linked oligoureas B , we prepared oligourea nonamer 2 containing Ala, Val, Leu, Phe, Tyr and Lys side chains. Oligomer 2 was synthesized on solid support from activated monomers, i.e., from enantiomerically pure succinimidyl {2‐{[(9H‐fluoren‐9‐ylmethoxy)carbonyl]amino}ethyl}carbamates 3a – f that are further substituted at C(2) of the ethyl moiety. These precursors were conveniently prepared from N‐Fmoc‐protected β3‐amino acids with corresponding side chains. Detailed NMR studies (DQF‐COSY, TOCSY, and ROESY) in (D5)pyridine revealed that 2 adopts a regular (P)‐2.5 helical secondary structure very similar to that previously determined for oligourea heptamer 1 and closely related to the (P)‐2.614 helix of γ‐peptides. Temperature‐dependent NMR further demonstrated the conformational homogeneity and remarkable stability of the structure of 2 in pyridine. The CD spectrum of 2 (0.2 mM ) was recorded in MeOH with the aim to gain more information about the conformation of oligoureas. In contrast to 2.6‐helical γ‐peptides, which display only a weak or no Cotton effect, oligourea 2 exhibits an intense positive Cotton effect at ca. 203 nm ([Θ]=+373000 deg cm2 dmol−1) that decreases only slowly upon increasing the temperature. 相似文献
80.
David Pertuit Anne-Claire Mitaine-Offer Tomofumi Miyamoto Chiaki Tanaka Christine Belloir Loïc Briand Marie-Aleth Lacaille-Dubois 《Molecules (Basel, Switzerland)》2021,26(22)
Four oleanane-type glycosides were isolated from a horticultural cultivar “Green Elf” of the endemic Pittosporum tenuifolium (Pittosporaceae) from New Zealand: three acylated barringtogenol C glycosides from the leaves, with two previously undescribed 3-O-β-d-glucopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→3)]-β-d-glucuronopyranosyl-21-O-angeloyl-28-O-acetylbarringtogenol C, 3-O-β-d-galactopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→3)]-β-d-glucuronopyranosyl-21-O-angeloyl-28-O-acetylbarringtogenol C, and the known 3-O-β-d-glucopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→3)]-β-d-glucuronopyranosyl-21-O-angeloyl-28-O-acetylbarringtogenol C (Eryngioside L). From the roots, the known 3-O-β-d-glucopyranosyl-(1→2)-β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyloleanolic acid (Sandrosaponin X) was identified. Their structures were elucidated by spectroscopic methods including 1D- and 2D-NMR experiments and mass spectrometry (ESI-MS). According to their structural similarities with gymnemic acids, the inhibitory activities on the sweet taste TAS1R2/TAS1R3 receptor of an aqueous ethanolic extract of the leaves and roots, a crude saponin mixture, 3-O-β-d-glucopyranosyl-(1→2)-[α-l-arabinopyranosyl-(1→3)]-β-d-glucuronopyranosyl-21-O-angeloyl-28-O-acetylbarringtogenol C, and Eryngioside L were evaluated. 相似文献