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71.
Georgakilas V Tagmatarchis N Pantarotto D Bianco A Briand JP Prato M 《Chemical communications (Cambridge, England)》2002,(24):3050-3051
High solubility of SWNTs and MWNTs in water is obtained by organic functionalisation; derivatisation with N-protected glycine is also easily achieved. 相似文献
72.
Bibal B Tinant B Declercq JP Dutasta JP 《Chemical communications (Cambridge, England)》2002,(5):432-433
The new tetra-thiophosphonatocavitand 1 in its iiii configuration extracts quantitatively Ag+ ions from aqueous solutions; the tetranuclear complex [1(2).Ag4Pic4] was selectively formed and characterized in the solid state by X-ray diffraction which revealed the formation of a new dimeric assembly through Ag+ coordination. 相似文献
73.
Dearden MJ Firkin CR Hermet JP O'Brien P 《Journal of the American Chemical Society》2002,124(40):11870-11871
A "(+)-sparteine-like" chiral diamine, readily synthesized in three steps from (-)-cytisine, has been evaluated in four different asymmetric transformations; in each case, selectivity in an enantiocomplementary fashion to (-)-sparteine was observed. 相似文献
74.
P. Brun 《The European Physical Journal C - Particles and Fields》2008,56(1):27-31
AMS-02 is a multi-purpose spectrometer with superconducting magnet, and is designed for 3 years of data taking aboard the
International Space Station. Its high performance regarding particle identification and energy measurement will allow performing
indirect searches for dark matter (DM) in different channels simultaneously: gamma rays, positrons and antiprotons. AMS-02
sensitivity to those signals are presented and – provided the positron excess is due to DM signal – it is shown that it allows
to probe new physics models in detail. Its high sensitivity could even be a unique opportunity to reach the Majorana nature
of the DM particle through final state polarization effects.
PACS 95.35.+d; 95.55.Vj 相似文献
75.
Jean-Paul Quintard Sabine Hauvette-Frey Michel Pereyre 《Journal of organometallic chemistry》1978,159(2):147-164
The metallation of aryl halides with tributylstannyllithium in THF proceeds via at least three different mechanisms whose relative rates depend on the nature of the halogen, the substrate and the experimental conditions. In the case of aryl bromides, a halogenmetal exchange (major process) is competing with a radical mechanism. With aryl chlorides, an arynic process, a halogenmetal exchange and a radical mechanism are involved. Finally, with aryl fluorides, the arynic process is usual, but it may be strongly competed by a radical mechanism whenever suitable experimental conditions are arranged. 相似文献
76.
Jean-Paul Biberian 《Surface science》1978,74(2):437-460
The adsorption of lead on gold at room temperature in UHV conditions has been studied by LEED and AES. We review some of the data obtained on the Au(100), (111), and (110) faces, published elsewhere, and we give some new experimental results on the stepped Au(S) [n(100) × (111)] (with n = 3, 4, 5, and 6) faces. On all these faces, as lead is deposited on the gold substrate it first forms a monolayer of lead, then a compound AuPb2. Using the LEED and Auger data we give a model of the epitaxy with a layer-by-layer growth mechanism. We propose a model which involves a transition alloy wich forms at the interface Au/AuPb2. This model is in agreement with the LEED diagrams observed before the one corresponding to bulk AuPb2. In the case of the epitaxy of lead on gold (100), we calculate the Auger peak-to-peak ] heights of the gold (72 eV) and lead (93 eV) transitions versus coverage. We obtain good agreement with the experimental data, assuming that the first and last layers of the alloy are lead monolayers and diffusion of lead in gold as well as gold in lead. 相似文献
77.
78.
John J. Daly Peter Schnholzer Jean-Paul Behr Jean-Marie Lehn 《Helvetica chimica acta》1981,64(5):1444-1451
The crystal and molecular structure of the complex formed by the ionized bistartro-[18]-crown-6 receptor molecule 1 with the ethylenediammonium cation, is described. The macrocycle is roughly planar, the carboxy groups of each tartaric acid residue being in a diaxial relationship and extending above and below this plane. This conformation allows ‘lateral’ interactions with bound species to occur. The substrate is sandwiched between two macrocycles, with one of its NH heads anchored to the polyether core, and the other one in contact with the two carboxy groups of the neighboring molecule. 相似文献
79.
Alt C Anticic T Baatar B Barna D Bartke J Betev L Białkowska H Billmeier A Blume C Boimska B Botje M Bracinik J Bramm R Brun R Buncić P Cerny V Christakoglou P Chvala O Cramer JG Csató P Darmenov N Dimitrov A Dinkelaker P Eckardt V Farantatos G Flierl D Fodor Z Foka P Freund P Friese V Gál J Gaździcki M Georgopoulos G Gładysz E Grebieszkow K Hegyi S Höhne C Kadija K Karev A Kliemant M Kniege S Kolesnikov VI Kollegger T Kornas E Korus R Kowalski M Kraus I Kreps M van Leeuwen M Lévai P Litov L 《Physical review letters》2005,94(19):192301
Results are presented on Omega production in central Pb+Pb collisions at 40 and 158A GeV beam energy. For the first time in heavy ion reactions, rapidity distributions and total yields were measured for the sum Omega(-) + Omega(+) at 40A GeV and for Omega(-) and Omega(+) separately at 158A GeV. The yields are strongly underpredicted by the string-hadronic UrQMD model but agree better with predictions from hadron gas models. 相似文献
80.
It is well known that any projective measurement can be decomposed into a sequence of weak measurements, which cause only small changes to the state. Similar constructions for generalized measurements, however, have relied on the use of an ancilla system. We show that any generalized measurement can be decomposed into a sequence of weak measurements without the use of an ancilla, and give an explicit construction for these weak measurements. The measurement procedure has the structure of a random walk along a curve in state space, with the measurement ending when one of the end points is reached. This shows that any measurement can be generated by weak measurements, and hence that weak measurements are universal. This may have important applications to the theory of entanglement. 相似文献