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31.
Wim Hesselink 《Mathematische Nachrichten》1977,79(1):189-191
32.
We report a high-intensity nano-aperture vertical-cavity surface-emitting laser (VCSEL) utilizing a bowtie-shaped aperture. A maximum power of 188 microW is achieved from a 180 nm bowtie aperture at a wavelength of 970 nm. The near-field full width at half-maximum intensity spot size 20 nm away from the bowtie aperture is 64 nm x 66 nm from simulation, and the peak near-field intensity is estimated to be as high as 47 mW/microm(2). This intensity is high enough to realize near-field optical recording, and the small spot size corresponds to storage densities up to 150 Gbits/in(2). The bowtie-aperture VCSEL also enables other applications, such as compact high-intensity probes for ultrahigh-resolution near-field imaging and single molecule fluorescence and spectroscopy. 相似文献
33.
We present a design for a subwavelength C-shaped optical waveguide with a 90 degrees junction that efficiently transports light while maintaining tight confinement with an exit spot size of lambda/7. Finite-difference time-domain simulations of perfect electric conductors and Au C-aperture waveguides are performed for optical frequencies. A design resonant near 780 nm is presented, with a spot size of 107 nm x 107 nm and an energy density enhancement factor of 10 for a bent waveguide of total length 1.4 microm. 相似文献
34.
Conclusions A three-dimensional auto-correlation function is proposed as a tool to analyse 3-D fluid flow datasets. In order to test this concept, we analysed time and space evolving datasets obtained from visualizations of the flow over a half-span delta wing. The processed slices show that the regions with strong vortical motion can easily be detected. However, it is much more difficult to determine the cross-stream velocity components. Obviously, some aspects need more attention before we can decide on the usefulness of this technique: (1) the effect of resolution and noise; (2) the smoothness of the smoke field must be controlled in order to get a large grey scale value variance; (3) the time interval between two recordings must correspond to the time scale of the cross stream motions; (4) the test flow must be less complex. 相似文献
35.
36.
Wim H. Hesselink 《Mathematische Zeitschrift》1982,179(1):135-149
37.
J. Ludziejewski A.W.B. Kalshoven W.H.A. Hesselink J. Bron A. Van Poelgeest H. Verheul M.J.A. De Voigt 《Nuclear Physics A》1980,344(2):266-282
The 103Ag nucleus has been studied using the 103Rh(α, 4nγ)103Ag and 103Rh(3He, 3nγ)103Ag reactions. A set of standard in-beam measurements involving relative excitation function measurements of γ-rays, γ-γ-Δt coincidences, conversion electron measurements and angular distribution and linear polarization measurements of emitted γ-rays have been performed. Excited states with spin values up to are populated in this nucleus. Among these excitations a positive-parity band built on the state can be distinguished. This band has similar properties as the band observed in 105Ag. The experimental data on the band in 103, 105Ag are compared to the prediction of the Nilsson model with Coriolis coupling at intermediate deformation ε = 0.10?0.15. Energy levels of the positive-parity bands are reproduced satisfactorily by the calculations assuming either a band head. However, electromagnetic properties of the levels, branching and mixing ratios, are better reproduced when assuming the band head. Attenuation of the Coriolis interaction was introduced in order to improve the fit of the calculated energies of the levels to the experimental values. 相似文献
38.
Perturbations of α-γ angular correlations in the decay of230U and226Th, involving the 2+ states in226Th and222Ra, have been studied using230U sources prepared by evaporation of the activity on Al foils, and226Th sources, prepared by collecting recoil nuclei from a230U source on Al foils. In vacuum, perturbation coefficients are found to be in agreement with the “hard-core-value” for static magnetic interaction. The perturbations in aluminum are found to be strongly dependent on the method of source preparation. 相似文献
39.
T. Kozlowski W. Bertl H.P. Povel U. sennhauser H.K. Walter A. Zglinski R. Engfer CH. Grab E.A. Hermes H.P. Isaak A. Van Der Schaaf J. Van Der Pluym W.H.A. Hesselink 《Nuclear Physics A》1985,436(4):717-732
Inclusive energy spectra and the energy dependence of the asymmetry parameter have been measured for neutrons emitted after muon capture in O, Si, Ca and Pb. In addition a neutron-neutron coincidence measurement has been performed for Ca. The results of these measurements confirm the exponential shape of the energy spectra and the positive asymmetry observed by Sundelin and Edelstein. The observation of neutrons with energies above 50 MeV and the observation of simultaneous emission of two high-energy neutrons suggest the importance of short-range nucleonnucleon correlations in this process. 相似文献
40.
P. Van Nes W.H.A. Hesselink W.H. Dickhoff J.J. Van Ruyven M.J.A. De Voigt H. Verheul 《Nuclear Physics A》1982,379(1):35-60
The 113, 115In(α, 3nγ)114, 116Sb reactions have been studied using γ-ray spectroscopic techniques. The experiments included γ-ray excitation function, γ-γ coincidence, lifetime, γ-ray angular distribution and conversion electron measurements. A ΔJ = 1 rotational band has been observed in either of the 114, 116Sb final nuclei. Energy spacings and electromagnetic properties of the band show strong resemblances with those of rotational bands in the adjacent odd-mass Sb nuclei. In addition two-quasiparticle and two-quasiparticle core coupled states have been observed in these nuclei. One isomer was identified in 116Sb, i.e. a Jπ = 11+ state at 1889 keV (). A simple model is proposed which explains the ΔJ = 1 band in terms of rotational alignment of the neutron with the deformed rotating odd-A core. 相似文献