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31.
A. Malvache X. Chen C. G. Durfee A. Jullien R. Lopez-Martens 《Applied physics. B, Lasers and optics》2011,104(1):5-9
We develop a numerical model to explore the polarization-dependent compression of multi-mJ laser pulses in a gas-filled hollow
fiber. We show how losses and instabilities due to cycling of pulse energy between fiber modes can be efficiently minimized
using circularly polarized light and adjusting simple experimental parameters such as pulse energy, chirp and gas pressure.
This should help scale the peak power of few-cycle pulses available for high-field experiments using standard hollow fiber
compressors. We also discuss the limits of this approach. 相似文献
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Onofrio R Durfee DS Raman C Kohl M Kuklewicz CE Ketterle W 《Physical review letters》2000,84(5):810-813
Surface modes in a Bose-Einstein condensate of sodium atoms have been studied. We observed excitations of standing and rotating quadrupolar and hexadecapolar modes. The modes were excited with high spatial and temporal resolution using the optical dipole force of a rapidly scanning laser beam. This novel technique is very flexible and should be useful for the study of rotating Bose-Einstein condensates and vortices. 相似文献
35.
By replacing the dispersive element in a zero-dispersion pulse shaper with a grism, we have constructed a quartic-phase-limited pulse shaper. We demonstrate compensation of 4500 fs2 without the use of a dynamic element in the pulse shaping line, which is approximately the amount of dispersion induced by a typical multiphoton microscope. We also demonstrate that detuning the pulse shaper to compensate for quadratic phase induces negligible spatial chirp, thereby maintaining a high-quality focal spot for a microscopy setup. 相似文献
36.
Cetin A Sripothongnak S Kawa M Durfee WS Ziegler CJ 《Chemical communications (Cambridge, England)》2007,(41):4289-4290
The syntheses and structural elucidations of three different cobalt complexes of m-benziphthalocyanine are reported; both Co(II) and Co(III) complexes can be generated, and the ring undergoes partial oxidation upon metalation with Co(OAc)2x4H2O. 相似文献
37.
GYÖRGY TARCZAY ATTILA G. CSÁSZÁR WIM KLOPPER HARRY M. QUINEY 《Molecular physics》2013,111(21):1769-1794
Relativistic energy corrections which arise from the use of the Dirac-Coulomb Hamiltonian, and the Gaunt and Breit interaction operators, plus Lamb-shift effects have been determined for the global minima of the ground electronic states of C2H6, NH3, H2O, [H,C,N], HNCO, HCOOH, SiC2, SiH? 3, and H2S, and for barrier characteristics for these molecular systems (inversion barrier of NH3 and SiH? 3, barrier to linearity of H2O, H2S, and HNCO, rotational barrier of C2H6, difference between conformations of HCOOH (Z/E) and SiC2 (linear/T-shaped), and isomerization barrier of HCN/HNC). The relativistic calculations performed at the Hartree-Fock and the highly correlated CCSD(T) levels employed a wide variety of basis sets. Comparison of the perturbational and the four-component fully variational results indicate that the Coulomb-Pauli Hamiltonian and the lowest order Hamiltonian of direct perturbation theory (DPT(2)) are highly successful for treating the relativistic energy effects in light molecular systems both at a single point on the potential energy hypersurface and along the surface. Electron correlation contributions to the relativistic corrections are relatively small for the systems studied, and are comparable with the 2-electron Darwin correction. Corrections beyond the Dirac-Coulomb treatment are usually rather small, but may become important for high accuracy ab initio calculations. 相似文献
38.
A contracting model for flexible distributed scheduling 总被引:1,自引:0,他引:1
We are interested in building systems of autonomous agents that can automate routine information processing activities in human organizations. Computational infrastructures for cooperative work should contain embedded agents for handling many routine tasks [9], but as the number of agents increases and the agents become geographically and/or conceptually dispersed, supervision of the agents will become increasingly problematic. We argue that agents should be provided with deep domain knowledge that allows them to make quantitatively justifiable decisions, rather than shallow models of users to mimic. In this paper, we use the application domain of distributed meeting scheduling to investigate how agents embodying deeper domain knowledge can choose among alternative strategies for searching their calendars in order to create flexible schedules within reasonable cost. 相似文献
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We present evidence for a nonsingular origin of the Universe with intial conditions determined by quantum physics and relativistic
gravity. In particular, we establish that the present temperature of the microwave background and the present density of the
Universe agree well with our predictions from these intial conditions, after evolution to the present age using the Einstein-Friedmann
equation. Remarkably, the quantum origin for the Universe naturally allows its evolution at exactly the critical density.
We also discuss the consequences of these results to some fundamental aspects of quantum physics in the early Universe. 相似文献