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Harvey Robin J. Lutz Michael A. Gallagher Hayden E. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1978,6(3):248-255
This paper describes the current interruption and voltage holdoff capabilities of a wide range of crossed-field tubes (XFTs). The XFTs investigated have active electrode areas ranging from 96 to 8000 cm2 with mean diameters from 2 to 56 cm. For the larger XFTs, currents up to 10 kA have been interrupted at voltages up to 100 kV, corresponding to a switched power of 1 GW. Experiments have shown the peak interruptible current to vary linearly with tube radius. The mechanism responsible for the limitation may be related to the self-generated magnetic field, but other factors are also shown to play a role. 相似文献
13.
Structure of States Which Satisfy Strong Subadditivity of Quantum Entropy with Equality 总被引:1,自引:1,他引:0
Patrick?Hayden Richard?Jozsa Dénes?Petz Andreas?WinterEmail author 《Communications in Mathematical Physics》2004,246(2):359-374
We give an explicit characterisation of the quantum states which saturate the strong subadditivity inequality for the von Neumann entropy. By combining a result of Petz characterising the equality case for the monotonicity of relative entropy with a recent theorem by Koashi and Imoto, we show that such states will have the form of a so–called short quantum Markov chain, which in turn implies that two of the systems are independent conditioned on the third, in a physically meaningful sense. This characterisation simultaneously generalises known necessary and sufficient entropic conditions for quantum error correction as well as the conditions for the achievability of the Holevo bound on accessible information. 相似文献
14.
15.
Coldea R Hayden SM Aeppli G Perring TG Frost CD Mason TE Cheong SW Fisk Z 《Physical review letters》2001,86(23):5377-5380
The magnetic excitations of the square-lattice spin-1/2 antiferromagnet and high- T(c) parent compound La2CuO4 are determined using high-resolution inelastic neutron scattering. Sharp spin waves with absolute intensities in agreement with theory including quantum corrections are found throughout the Brillouin zone. The observed dispersion relation shows evidence for substantial interactions beyond the nearest-neighbor Heisenberg term which can be understood in terms of a cyclic or ring exchange due to the strong hybridization path around the Cu4O4 square plaquettes. 相似文献
16.
Andresen GB Ashkezari MD Baquero-Ruiz M Bertsche W Bowe PD Butler E Carpenter PT Cesar CL Chapman S Charlton M Fajans J Friesen T Fujiwara MC Gill DR Hangst JS Hardy WN Hayden ME Humphries AJ Hurt JL Hydomako R Jonsell S Madsen N Menary S Nolan P Olchanski K Olin A Povilus A Pusa P Robicheaux F Sarid E Silveira DM So C Storey JW Thompson RI van der Werf DP Wurtele JS Yamazaki Y;ALPHA Collaboration 《Physical review letters》2011,106(2):025002
We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination. 相似文献
17.
Laboratory experiments have been conducted in two separate boundary layer facilities to investigate steady spanwise variations
in mean velocity discovered during studies of developing flows over regular arrays of large roughness elements. Regular spanwise
variation was found with a steady wavelength, moderated by the growing boundary layer, which was an integer multiple of the
repeating unit of roughness. Amplitude variations greater than ±5% in the mean were found over the roughness and greater than
±10% in turbulence quantities. Due to the dominating nature of this phenomena throughout the layer, care should be taken in
undertaking local measurements aimed at identifying flow variations caused by roughness heterogeneity. 相似文献
18.
Pfiester J.R. Parrillo L.C. Hayden J.D. See Y.-C. Fejes P. 《Electron Device Letters, IEEE》1989,10(8):367-369
The effect of poly-gate sidewall oxidation on short-channel MOSFET behavior is examined. The gain, threshold voltage, and apparent electrical channel length are shown to be very sensitive to the location of the n- junction edge with respect to the poly-gate edge for a lightly-doped-drain NMOS transistor. New guidelines for the design of submicrometer MOSFETs based on an analysis of the sidewall oxidation of the polysilicon after gate definition are proposed 相似文献
19.
Pfiester J.R. Baker F.K. Mele T.C. Tseng H.-H. Tobin P.J. Hayden J.D. Miller J.W. Gunderson C.D. Parrillo L.C. 《Electron Devices, IEEE Transactions on》1990,37(8):1842-1851
The penetration of boron into and through the gate oxides of PMOS devices which employ p+ doped polysilicon gates is studied. Boron penetration results in large positive shifts in V FB , increased PMOS subthreshold slope and electron trapping rate, and decreased low-field mobility and interface trap density. Fluorine-related effects caused by BF2 implantations into the polysilicon gate are shown to result in PMOS threshold voltage instabilities. Inclusion of a phosphorus co-implant or TiSi2 salicide prior to gate implantation is shown to minimize this effect. The boron penetration phenomenon is modeled by a very shallow, fully-depleted p-type layer in the silicon substrate close to the SiO 2/Si interface 相似文献
20.
We demonstrate time reversal of nuclear spin dynamics in highly magnetized dilute liquid (3)He-(4)He mixtures through effective inversion of long-range dipolar interactions. These experiments, which involve using magic sandwich NMR pulse sequences to generate spin echoes, probe the spatiotemporal development of turbulent spin dynamics and promise to serve as a versatile tool for the study and control of dynamic magnetization instabilities. We also show that a repeated magic sandwich pulse sequence can be used to dynamically stabilize modes of nuclear precession that are otherwise intrinsically unstable. To date, we have extended the effective precession lifetimes of our magnetized samples by more than three orders of magnitude. 相似文献