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Measurements of synchrotron radiation emitted by 30-MeV runaway electrons in the TEXTOR-94 tokamak show that the runaway population decays after switching on neutral beam injection (NBI). The decay starts only with a significant delay, which decreases with increasing NBI heating power. This delay provides direct evidence of the energy dependence of runaway confinement, which is expected if magnetic modes govern the loss of runaways. Application of the theory by Mynick and Strachan [Phys. Fluids 24, 695 (1981)] yields estimates for the "mode width" (delta) of magnetic perturbations: delta<0.5 cm in Ohmic discharges, increasing to delta = 4.4 cm for 0. 6 MW NBI. 相似文献
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Bose-Einstein condensation in a gas of sodium atoms 总被引:2,自引:0,他引:2
Davis KB Mewes M Andrews MR van Druten NJ Durfee DS Kurn DM Ketterle W 《Physical review letters》1995,75(22):3969-3973
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Glassmaker NJ Hui CY Yamaguchi T Creton C 《The European physical journal. E, Soft matter》2008,25(3):253-266
New experimental results are presented about the final stage of failure of soft viscoelastic adhesives. A microscopic view
of the detachment of the adhesive shows that after cavity growth and expansion, well adhered soft adhesives form a network
of fibrils connected to expanded contacting feet which fail via a sliding mechanism, sensitive to interfacial shear stresses
rather than by a fracture mechanism as sometimes suggested in earlier work. A mechanical model of this stretching and sliding
failure phenomenon is presented which treats the fibril as a nonlinear elastic or viscoelastic rod and the foot as an elastic
layer subject to a friction force proportional to the local displacement rate. The force on the stretched rod drives the sliding
of the foot against the substrate. The main experimental parameter controlling the failure strain and stress during the sliding
process is identified by the model as the normalized probe pull speed, which also depends on the magnitude of the friction
and PSA modulus. In addition, the material properties, viscoelasticity and finite extensibility of the polymer chains, are
shown to have an important effect on both the details of the sliding process and the ultimate failure strain and stress.
Electronic supplementary material Appendix B is only available in electronic form at
and are accessible for authorised users. 相似文献
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A new approach to on-line oxygen isotope analysis has been developed which utilises existing elemental analyser and mass spectrometry technology to produce a sample of carbon dioxide gas for oxygen isotople analysis. The method relies on on-line high temperature pyrolysis of the sample over a carbon source followed by a rapid, non-contributive partial catalytic oxidation over nickel powder at between 550 and 600 degrees C. Initial results demonstrate both good precision (better than 0.2 per thousand) and accuracy for both cellulose and silver nitrate samples. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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Tingye Li AT&T Middletown NJ USA Zisen Zhao Wuhan Research Institute of Post Telecommunications Fiberhome Wuhan ChinaJianjun Yu ZTE USA Inc. wood ave. south FL Iselin NJ USA ZTE Inc. Beijing China 《中国光学快报(英文版)》2010,(9):815-815
<正>Fiber optics underpins the communications infrastructure for the information society today. Cables consisting of hair-like fibers speed data around the globe in the form of rapid pulses of light. Modern telecom 相似文献
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谢崇进 《中国光学快报(英文版)》2010,(9):844-851
Using numerical simulations, the nonlinear transmission performance of polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) coherent systems is studied. It is found that inter-channel cross-polarization modulation (XPolM) induced nonlinear polarization scattering can significantly degrade the transmission performance of PDM-QPSK coherent systems and change the perspective of dispersion management in optical coherent transmission systems. Some techniques to mitigate nonlinear polarization scattering in dispersion-managed PDM coherent transmission systems are discussed, including the use of time-interleaved return-to-zero (RZ) PDM formats, the use of periodic-group-delay PGD dispersion compensators, and the judicious addition of some polarization-mode-dispersion (PMD) in the transmission link. It is shown that if nonlinear polarization scattering can be well mitigated, a polarization multiplexed optical coherent transmission system with dispersion management could perform better than that without it. 相似文献
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Mantica P Gorini G Hogeweij GM Lopes Cardozo NJ Schilham AM 《Physical review letters》2000,85(21):4534-4537
Layers of reduced electron heat transport ("transport barriers") have been observed in the Rijnhuizen Tokamak Project when the plasma is dominantly heated by electron cyclotron heating (ECH). Experiments into the properties of the transport barriers are reported. Modulation of the ECH power was used to probe electron heat transport in the barriers by means of propagating electron temperature perturbations. The observed propagation shows that transport inside the barriers is dominated by heat convection. This convection is inward, i.e., up the temperature gradient. 相似文献