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961.
962.
963.
R. T. de Souza N. Le Neindre A. Pagano K. -H. Schmidt 《The European Physical Journal A - Hadrons and Nuclei》2006,30(1):275-291
This review on second- and third-generation multidetectors devoted to heavy-ion collisions aims to cover the last twenty years.
The presented list of devices is not exhaustive but regroups most of the techniques used during this period for nuclear reactions
at intermediate energy (≃ 10A MeV to 1A GeV), both for charged-particle and neutron detection. The main part will be devoted
to 4π multidetectors, projectile decay fragmentation, high-resolution magnetic spectrometers, auxiliary detectors and neutron
detection. The last part will present the progress in electronics and detection in view of the construction of future-generation
detectors. 相似文献
964.
The gas phase reaction of OH radicals with hydrogen iodide (HI) has been studied using a Laser Photolysis-Resonance Fluorescence (LP-RF) apparatus, recently developed in our group. The measured rate constant at 298 K was (2.7 ± 0.2) × 10−11 cm3 molecule−1 s−1. This rate constant is compared with the ones of the reactions OH + HCl and OH + HBr. The role of the reaction OH + HI in marine tropospheric chemistry is discussed. In addition, the LP-RF apparatus was tested and validated by measuring the following rate constants (in cm3 molecule−1 s−1 units): 𝓀(OH + HNO3) = (1.31 ± 0.06) × 10−13 at p = 27 and 50 Torr of argon and 𝓀(OH + C3H8) = (1.22 ± 0.08) × 10−12. These rate constants are in very good agreement with the literature data. 相似文献
965.
966.
We study the hydrodynamic expansion of a rotating strongly interacting Fermi gas by releasing a cigar-shaped cloud with a known angular momentum from an optical trap. As the aspect ratio of the expanding cloud approaches unity, the angular velocity increases, indicating quenching of the moment of inertia I to as low as 0.05 of the rigid body value I(rig). Remarkably, we observe this behavior in both the superfluid and collisional normal fluid regimes, which obey nearly identical zero-viscosity irrotational hydrodynamics. We attribute irrotational flow in the normal fluid to a decay of the rotational part of the stream velocity during expansion, which occurs when the shear viscosity is negligible. Using conservation of angular momentum, we directly observe a fundamental result of irrotational hydrodynamics, I/I(rig) = delta2, where delta is the deformation parameter of the cloud. 相似文献
967.
We present a method of simulating the Dirac equation in 3+1 dimensions for a free spin-1/2 particle in a single trapped ion. The Dirac bispinor is represented by four ionic internal states, and position and momentum of the Dirac particle are associated with the respective ionic variables. We show also how to simulate the simplified 1+1 case, requiring the manipulation of only two internal levels and one motional degree of freedom. Moreover, we study relevant quantum-relativistic effects, like the Zitterbewegung and Klein's paradox, the transition from massless to massive fermions, and the relativistic and nonrelativistic limits, via the tuning of controllable experimental parameters. 相似文献
968.
Le Gouët J Morvan L Alouini M Bourderionnet J Dolfi D Huignard JP 《Optics letters》2007,32(9):1090-1092
We demonstrate the generation of optically carried, broadly tunable, millimeter-wave signals with a dual-frequency single-axis Nd:YAG laser. A frequency difference as high as 127 GHz is reached thanks to an intracavity electro-optically tunable etalon made of lead zirconate tantalate (PLZT) ceramic. We show that the available frequency range is actually limited by the bandwidth of the amplification medium, namely, far beyond the usually accepted free spectral range value in the case of a single-axis laser. Both coarse discrete and fine continuous tunabilities are obtained with the same voltage-controlled device, opening the way to widely tunable low-phase-noise optically carried submillimeter or even terahertz sources. 相似文献
969.
970.
Reaction of 1-germatranol hydrate with carboxylic acids RCOOH (R = ClCH2, PhCH=CH, Ph, 2-FC6H4, 3-BrC6H4, 3-HOC6H4, 3-EtOC6H4) in protic (CH3OH, iso-C5H11OH) and aprotic polar solvent (CH3CN) is studied. 1-Acyloxygermatranes RC(O)OGe(OCH{in2}CH{in2}){in3}N are formed in yields from 11 to ~100 % depending on the nature of the acid, solvent, duration of the process and the method of its completion. The reaction is the most effective in acetonitrile. Its topochemical completion (heating of the reaction residue in a vacuum) increases the yield of 1-acyloxygermatranes. 相似文献