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151.
N.I. Voropaev D.V. Balin W.N. Breunlich T. Case K.M. Crowe H. Daniel V.A. Ganzha B. Gartner F.J. Hartmann P. Kammel S.M. Kozlov B. Lauss E.M. Maev V.E. Markushin Yu.A. Misko M. Mühlbauer C. Petitjean G.E. Petrov W. Prymas G.N. Schapkin W. Schott G.G. Semenchuk Yu.V. Smirenin V.A. Trofimov A.A. Vasiliev A.A. Vorobyov J. Zmeskal 《Hyperfine Interactions》1999,118(1-4):135-140
We present the results of precision measurements of dμ spin-flip rates in pure D2, in pure HD gas, and in the non-equilibrium and equilibrium H2+D2 gas mixtures. The experiments were performed at PSI in 1994-1996 using the high pressure ionization chamber from Gatchina
as a 100% efficient detector of the charged fusion products. The measurements have been carried out in the temperature range
28-300 K, at gas density of 5% of LHD. In pure deuterium, the measured temperature dependence of the spin-flip rate allowed
us to separate the two components (resonant and non-resonant) of the spin-flip processes. From the experiments in H/D mixtures
we have measured the non-resonant spin-flip rate in collisions of dμ-atoms with HD molecules. Comparison with the theory revealed considerable disagreement in the case of non-resonant spin-flip
in collisions of the dμ-atoms with D2 molecules.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
152.
E.M. Maev D.V. Balin T. Case K.M. Crowe A. Del Rosso V.A. Ganzha F.J. Hartmann S.M. Kozlov B. Lauss O.E. Maev M. Mühlbauer F. Mulhauser C. Petitjean G.E. Petrov S.M. Sadetsky G.N. Schapkin W. Schott G.G. Semenchuk Yu.V. Smirenin M.A. Soroka A.A. Vasiliev A.A. Vorobyov N.I. Voropaev J. Zmeskal 《Hyperfine Interactions》1999,118(1-4):171-176
We report on the results of an experiment aimed at observing muon-catalyzed d
3He-fusion with a setup previously used for studies of the muon-catalyzed dd-fusion. The basic element of the setup is a high
pressure ionization chamber operating as an active target. In this experiment the chamber was filled with an HD + 3He (5.6%) gas mixture at 13.2 bar pressure and 50 K temperature. These conditions were chosen as optimal for formation of
the 3Heμd-molecules with a low level of background from the d-μ-d fusion. The chamber was exposed to the negative muon beam at PSI. During a 3-week data-taking period, 9.7 × 108 muon stops have been selected. The analysis of the data was able to determine a new upper limit for the d
3He-fusion rate in the 3Heμd-molecule (λf≤ 6× 104 s-1), which is more than three orders of magnitude lower than the previously existed limit.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
153.
B.D. Patterson K.M. Crowe F.N. Gygax R.F. Johnson A.M. Portis J.H. Brewer 《Physics letters. A》1974,46(7):453-454
We have observed long-lived μ+ precession in single crystal nickel at 300 and 77K. Inhomogeneous local fields which cause rapid depolarization in polycrystalline samples are avoided. Muon precession in a magnetically saturated sample is reported. 相似文献
154.
Chung P Ajitanand NN Alexander JM Anderson M Best D Brady FP Case T Caskey W Cebra D Chance JL Cole B Crowe K Das AC Draper JE Gilkes ML Gushue S Heffner M Hirsch AS Hjort EL Holzmann W Huo L Issah M Justice M Kaplan M Keane D Kintner JC Klay J Krofcheck D Lacey RA Lauret J Lisa MA Liu H Liu YM Milan J McGrath R Milosevich Z Odyniec G Olson DL Panitkin S Porile NT Rai G Ritter HG Romero JL Scharenberg R Srivastava B Stone NT Symons TJ Taranenko A Whitfield J Wienold T Witt R Wood L Zhang WN 《Physical review letters》2003,91(20):202301
The yield for the multistrange Xi(-) hyperon has been measured in 6A GeV Au+Au collisions via reconstruction of its decay products pi(-) and Lambda, the latter also being reconstructed from its daughter tracks of pi(-) and p. The measurement is rather close to the threshold for Xi(-) production and therefore provides an important test of model predictions. The measured yield for Xi(-) and Lambda are compared for several centralities. In central collisions the Xi(-) yield is found to be in excellent agreement with statistical and transport model predictions, suggesting that multistrange hadron production approaches chemical equilibrium in high baryon density nuclear matter. 相似文献
155.
Chung P Ajitanand NN Alexander JM Anderson M Best D Brady FP Case T Caskey W Cebra D Chance JL Cole B Crowe K Das AC Draper JE Gilkes ML Gushue S Heffner M Hirsch AS Hjort EL Holzmann W Huo L Issah M Justice M Kaplan M Keane D Kintner JC Klay J Krofcheck D Lacey RA Lauret J Lisa MA Liu H Liu YM McGrath R Milosevich Z Odyniec G Olson DL Panitkin S Porile NT Rai G Ritter HG Romero JL Scharenberg R Srivastava B Stone NT Symons TJ Taranenko A Whitfield J Witt R Wood L Zhang WN Brown D Pratt S 《Physical review letters》2003,91(16):162301
Source images are extracted from two-particle correlations constructed from strange and nonstrange hadrons produced in 6A GeV Au+Au collisions. Very different source images result from pp vs p Lambda vs pi(-)pi(-) correlations. Scaling by transverse mass can describe the apparent source size ratio for p/pi(-) but not for Lambda/pi(-) or Lambda/p. These observations suggest important differences in the space-time emission histories for protons, pions, and neutral strange baryons produced in the same events. 相似文献
156.
A series of new tributylstannyl ethers of simple sugars has been prepared by the reaction of bis(tributyltin) oxide with the appropriate mono- or disaccharide; chemical and spectroscopic evidence suggests that the 1-, 4- and 6-hydroxyl groups are the most reactive towards the trialkyltin compound. 相似文献
157.
158.
Alan J Crowe 《应用有机金属化学》1987,1(2):143-155
The object of this review paper is to provide a guide to agrochemical research involving organotin compounds which has been performed since 1980. The information is presented in tabular form and Part I is divided into main sections as indicated by the title. Each section is then subdivided to cover the various commercial organotin compounds. A final subsection lists investigations involving novel compounds. A table of the contents has been provided to enable ease of reference. 相似文献
159.
C. Petitjean D.V. Balin W.H. Breunlich T. Case K.M. Crowe H. Daniel M.P. Faifman V.A. Ganzha B. Gartner F.J. Hartmann P. Kammel S. Kozlov B. Lauss E.M. Maev V.E. Markushin Yu.A. Misko M. Mühlbauer G.E. Petrov W. Prymas G.N. Schapkin W. Schott G.G. Semenchuk Yu.V. Smirenin V.A. Trofimov A.A. Vasiliev A.A. Vorobyov N.I. Voropaev J. Zmeskal 《Hyperfine Interactions》1999,118(1-4):127-133
We present the results of an experiment performed at PSI to investigate muon catalyzed fusion in pure deuterium gas of 5%
density (LHD) at temperatures ranging from 28 K to 350 K. Using a new high pressure ionization chamber the reactions dd → n + 3He and dd → p+t were observed with 100% detection efficiency. The rates of dμd formation were measured with the absolute precision of 1% and the μd spin-flip rates with 0.5%. The temperature dependence of molecular formation and spin-flip rates display pronounced resonance
structures. A preliminary fit based on the Vesman mechanism of resonant muonic molecule formation was carried out yielding
a dd fusion rate of 3.5·108 s-1 and a hfs splitting energy
of 24.3 meV, both in good agreement with the theory.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
160.
Metallic triflates M(OTf)(3) (M = Bi, Sc, Yb), immobilized in imidazolium ionic liquids [BMIM][BF(4)], [BMIM][PF(6)] and [BMIM][OTf] are efficient systems for one-pot reactions of propargylic alcohols 1,3-diphenyl-2-propyn-1-ol Ia, 1-methyl-3-phenyl-2-propyn-1-ol Ib, and 2-pentyn-1-ol Ic, with a wide range of arenes bearing activating substituents, under mild conditions. The [BMIM][PF(6)]/B(C(6)F(5))(3) and [BMIM][PF(6)]/TfOH systems were superior in propargylation with Ib and Ic, while reaction of 3-phenyl-2-propyn-1-ol Id with activated aromatics resulted in the formation of diaryl-propanones instead. Propargylation of anisole with Ib under M(OTf)(3) catalysis is highly para selective, but with TfOH or B(C(6)F(5))(3) as catalyst the ortho isomer was also formed. Steric influence of the propargylic moiety on substrate selectivity is reflected in the lack of ortho propargylation for phenol and ethylbenzene by using propargylic alcohol Ia, and notable formation of the ortho isomer employing alcohol Ib. In the later case para selectivity could be increased by running the reaction at r. t. for 10 h. The Bi(OTf)(3)-catalyzed reaction of 1,3-dimethoxybenzene with Ia led to minor formation of dipropargylated derivative, along with the monopropargyl product. Propargylation of the less reactive arenes (mesitylene, ethylbenzene, toluene), using Sc(OTf)(3) as catalyst, led increasingly to the formation of dipropargylic ethers and propargyl ketones, with no ring propargylation product with toluene. Concomitant formation of dipropargylic ether was also observed in Yb(OTf)(3)-catalyzed propargylation of β-naphthol, whereas propargylation of 2-nitro and 4-nitro-aniline led to N-propargylation. The recycling/reuse of the IL was demonstrated in representative cases with no appreciable decrease in the conversions over 3 cycles. It was also shown that recycled IL could be used to propargylate a different aromatic compound. The efficacy of IL/M(OTf)(3) and IL/TfOH systems for cross-breeding two propargylic alcohols or a propargylic alcohol with a non-propargylic alcohol and/or self-coupling, to form a wide variety of functionalized ethers is also demonstrated. 相似文献