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121.
The phase diagram of SU(3) lattice gauge theories with Susskind fermions is investigated by Monte Carlo methods. For three flavors in the continuum a significant shift in the location of the peak in the specific heat is found, as compared to the pure gauge case. These results suggest that the crossover region moves to smaller β when fermion polarization effects are included. 相似文献
122.
Deng H Press D Götzinger S Solomon GS Hey R Ploog KH Yamamoto Y 《Physical review letters》2006,97(14):146402
We study the momentum distribution and relaxation dynamics of semiconductor microcavity polaritons by angle-resolved and time-resolved spectroscopy. Above a critical pump level, the thermalization time of polaritons at positive detunings becomes shorter than their lifetime, and the polaritons form a quantum degenerate Bose-Einstein distribution in thermal equilibrium with the lattice. 相似文献
123.
Nazikian R Berk HL Budny RV Burrell KH Doyle EJ Fonck RJ Gorelenkov NN Holcomb C Kramer GJ Jayakumar RJ La Haye RJ McKee GR Makowski MA Peebles WA Rhodes TL Solomon WM Strait EJ Vanzeeland MA Zeng L 《Physical review letters》2006,96(10):105006
Evidence is presented for a multitude of discrete frequency Alfvén waves in the core of magnetically confined high-temperature fusion plasmas. Multiple diagnostic instruments confirm wave excitation over a wide spatial range from the device size at the longest wavelengths down to the thermal ion Larmor radius. At the shortest scales, the poloidal wavelengths are comparable to the scale length of electrostatic drift wave turbulence. Theoretical analysis confirms a dominant interaction of the modes with particles in the thermal ion distribution traveling well below the Alfvén velocity. 相似文献
124.
Nguyen Van D Muppala SR Frech W Tesfalidet S 《Analytical and bioanalytical chemistry》2006,386(5):1505-1513
A method combining liquid/liquid extraction and chromatographic fractionation has been developed for the preparation of pure
monophenyltin (MPhT), diphenyltin (DPhT), and triphenyltin (TPhT), synthesized from isotope-enriched Sn metal using phenylation
of SnI4 in diethylether (DEE) followed by quenching with HBr and water. After two successive extractions of the aqueous HBr phase
with DEE, >99% of both DPhT and TPhT was recovered in the combined DEE phase and 94% of the MPhT remained in the aqueous phase.
The MPhT in the aqueous phase was extracted into dichloromethane. The organic phases were vaporized and the PhTs were redissolved
in MeOH/water/acetic acid/sodium acetate (59/30/6/8, v/v/v/w), which was also used as storing solution. Aliquots of the two
solutions containing either DPhT and TPhT or MPhT were injected into a silica-based C18 column for isolating and purifying single species. The yields of pure MPhT, DPhT, and TPhT, each synthesized from isotope-enriched
118Sn metal, 122Sn metal, and 124Sn metal, were better than 99%. After chromatographic separation, the single phenyltin compounds were mixed to prepare a spike
for multiple-isotope species-specific isotope dilution (MI-SSID). MI-SSID was successfully used to determine phenyltin compounds
in the certified reference material, mussel tissue BCR CRM-477. At −20 °C, all of the fractionated phenyltin species were
stable in the storage solution for at least 197 days. When these standards were stored at 4 °C or 22 °C, 4–6% of the DPhT
and TPhT degraded within 27 days. The degradation of DPhT and TPhT increased with the ionic strength and acidity of the storage
solution.
相似文献
125.
We show that every countable ideal of degrees that are low for isomorphism is contained in a principal ideal of degrees that are low for isomorphism by adapting an exact pair construction. We further show that within the hyperimmune free degrees, lowness for isomorphism is entirely independent of computable traceability. 相似文献
126.
127.
128.
We discuss microscopic mechanisms of complex network growth, with the special emphasis of how these mechanisms can be evaluated from the measurements on real networks. As an example we consider the network of citations to scientific papers. Contrary to common belief that its growth is determined by the linear preferential attachment, our microscopic measurements show that it is driven by the nonlinear autocatalytic growth. This invalidates the scale-free hypothesis for the citation network. The nonlinearity is responsible for a dramatic dynamical phase transition: while the citation lifetime of majority of papers is 6–10 years, the highly-cited papers have practically infinite lifetime. 相似文献
129.
Nazikian R Fu GY Austin ME Berk HL Budny RV Gorelenkov NN Heidbrink WW Holcomb CT Kramer GJ McKee GR Makowski MA Solomon WM Shafer M Strait EJ Zeeland MA 《Physical review letters》2008,101(18):185001
Intense axisymmetric oscillations driven by suprathermal ions injected in the direction counter to the toroidal plasma current are observed in the DIII-D tokamak. The modes appear at nearly half the ideal geodesic acoustic mode frequency, in plasmas with comparable electron and ion temperatures and elevated magnetic safety factor (q_{min}>or=2). Strong bursting and frequency chirping are observed, concomitant with large (10%-15%) drops in the neutron emission. Large electron density fluctuations (n[over ]_{e}/n_{e} approximately 1.5%) are observed with no detectable electron temperature fluctuations, confirming a dominant compressional contribution to the pressure perturbation as predicted by kinetic theory. The observed mode frequency is consistent with a recent theoretical prediction for the energetic-particle-driven geodesic acoustic mode. 相似文献
130.
The photoluminescence spectrum of a single quantum dot was recorded as a secondary resonant laser optically dressed either the vacuum-to-exciton or the exciton-to-biexciton transitions. High-resolution polarization-resolved measurements using a scanning Fabry-Pérot interferometer reveal splittings of the linearly polarized fine-structure states that are nondegenerate in an asymmetric quantum dot. These splittings manifest as either triplets or doublets and depend sensitively on laser intensity and detuning. Our approach realizes complete resonant control of a multiexcitonic system in emission, which can be either pulsed or continuous wave, and offers direct access to the emitted photons. 相似文献