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N. Zurlo M. Amoretti C. Amsler G. Bonomi C. Carraro C. L. Cesar M. Charlton M. Doser A. Fontana R. Funakoshi P. Genova R. S. Hayano L. V. Jørgensen A. Kellerbauer V. Lagomarsino R. Landua E. Lodi Rizzini M. Macrì N. Madsen G. Manuzio D. Mitchard P. Montagna L. G. Posada H. Pruys C. Regenfus A. Rotondi G. Testera D. P. Van der Werf A. Variola L. Venturelli Y. Yamazaki 《Hyperfine Interactions》2006,172(1-3):97-105
We descrbe how protonium, the quasi-stable antiproton-proton bound system, has been synthesized following the interaction
of antiprotons with the molecular ion in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events
in the ATHENA experiment, evidence is presented for protonium production with sub-eV kinetic energies in states around n = 70, with low angular momenta. This work provides a new two-body system for studies using laser spectroscopic techniques.
相似文献
33.
Kazuhiro Kobayashi Toshiyuki Nagaoka Yuu Shirai Wataru Miyatani Yuki Yokoi Hisatoshi Konishi 《Helvetica chimica acta》2012,95(2):191-196
A new type of isocoumarins (=1H‐isochromen‐1‐ones=1H‐2‐benzopyran‐1‐ones), 4‐substituted 3,4‐dihydro‐3‐methoxyisocoumarins 2 , can be obtained by a one‐pot process from α‐substituted 2‐bromo‐β‐methoxystyrenes 1 . Thus, lithium 2‐(1‐aryl(or methyl)‐2‐methoxyethenyl)benzoates are conveniently generated via the Br/Li exchange between 1 and BuLi, followed by the action of CO2 on the resulting α‐substituted 2‐lithio‐β‐methoxystyrenes. Upon treating with concentrated HCl at room temperature, these lithium benzoates undergo lactonization to provide the desired 3,4‐dihydroisocoumarins 2 in relatively good yields. 相似文献
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ATHENA Collaboration M. Amoretti C. Amsler G. Bonomi A. Bouchta P. D. Bowe C. Carraro C. L. Cesar M. Charlton M. Doser V. Filippini A. Fontana M. C. Fujiwara R. Funakoshi P. Genova J. S. Hangst R. S. Hayano L. V. Jrgensen A. Kellerbauer V. Lagomarsino R. Landua D. Lindelof E. Lodi Rizzini M. Macrí N. Madsen G. Manuzio P. Montagna H. Pruys C. Regenfus A. Rotondi G. Testera A. Variola L. Venturelli D. P. van der Werf Y. Yamazaki 《Physics letters. [Part B]》2004,590(3-4):133-142
We demonstrate cooling of 104 antiprotons in a dense, cold plasma of 108 positrons, confined in a nested cylindrical Penning trap at about 15 K. The time evolution of the cooling process has been studied in detail, and several distinct types of behavior identified. We propose explanations for these observations and discuss the consequences for antihydrogen production. We contrast these results with observations of interactions between antiprotons and “hot” positrons at about 3000 K, where antihydrogen production is strongly suppressed. 相似文献
36.
Tanaka M Imai M Fujio M Sakamoto E Takahashi M Eto-Kato Y Wu XM Funakoshi K Sakai K Suemune H 《The Journal of organic chemistry》2000,65(18):5806-5816
Asymmetric cyclization of symmetrical 3,4-disubstituted and 3,3, 4-trisubstituted 4-pentenals was studied using Rh-complexes with chiral ligands. The cyclization of symmetrical 4-pentenals 4a,b by a neutral Rh[(R)-BINAP]Cl afforded cis-3,4-disubstituted (4R)-cyclopentanones 9a,b of >95% ee in 25-31% yields; on the other hand, the cyclization of 4a-c by a cationic Rh[(R)-BINAP]ClO(4) afforded trans-3,4-disubstituted (4S)-cyclopentanones 10a-c of >95% ee in 70-81% yields. All stereoisomers could be stereoselectively made by the selection of a neutral or cationic Rh-complex, and (R)- or (S)-BINAP ligand. The Rh-catalyzed cyclization could be applied to the construction of cyclopentanones 17 and 18 bearing a chiral quaternary carbon. The cyclization by the cationic Rh[(R)-BINAP]ClO(4) afforded the optically active trans-3,3, 4-trisubstituted cyclopentanones 18a-c of 92-95% ee in 75-83% yields. The catalytic cycle was also studied by using deuterium aldehyde, and the tentative mechanisms of the enantio- and diastereoselection were proposed. 相似文献
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T Funakoshi H Shimada S Kojima S Shoji Y Kubota T Morita N Tominaga H Ueki 《Chemical & pharmaceutical bulletin》1992,40(1):174-176
Sodium orthovanadate (vanadate) prolonged the clotting time of normal human plasma in a dose-dependent manner. The prolongation of clotting time by vanadate linearly decreased with an increase in the concentration of amiloride. Vanadate also was completely additive to prolongation by heparin. When factor Xa or thrombin was incubated with vanadate, the amidolytic activity of each decreased in a dose-dependent manner with vanadate. Amiloride protected the decrease of amidolytic activity of both factor Xa and thrombin by vanadate. The amidolytic activity of trypsin also was inhibited by vanadate, but that of alpha-chymotrypsin was not inhibited, suggesting that vanadate preferentially inhibits the amidolytic activity of trypsin and trypsin-like enzymes. These results show that vanadate prolongs the clotting time of plasma through mechanisms involving in part the inhibition of the activity of both factor Xa and thrombin. 相似文献
40.
Powerful Claisen ester condensations of alpha,alpha-dialkylated esters mediated by ZrCl4-iPr2NEt were performed to give the corresponding thermodynamically unfavorable alpha,alpha-dialkylated beta-ketoesters, and Claisen-aldol tandem reactions between an intermediary Zr-enolate of a alpha,alpha-dialkylated beta-ketoester and aldehydes also proceeded. 相似文献