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I.?BarbEmail author R.?Gerritsma Y. T.?Xing J. B.?Goedkoop R. J.C.?Spreeuw 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,35(1):75-79
We present designs for Ioffe-Pritchard type magnetic traps using planar patterns of hard magnetic material. Two samples with different pattern designs were produced by spark erosion of
40 μm thick FePt foil. The pattern on the first sample yields calculated axial and radial trap frequencies of 51 Hz and 6.8 kHz, respectively. For the second sample the calculated frequencies are
34 Hz and 11 kHz. The structures were used successfully as a magneto-optical trap for 87Rb and loaded as a magnetic trap. A third design, based on lithographically patterned 250 nm thick
FePt film on a Si substrate, yields an array of 19 traps with calculated axial and radial trap frequencies of 1.5 kHz and 110 kHz, respectively. 相似文献
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Simple Zeros of the Riemann Zeta-Function 总被引:1,自引:0,他引:1
Assuming the Riemann Hypothesis, Montgomery showed by meansof his pair correlation method that at least two-thirds of thezeros of Riemann's zeta-function are simple. Later he and Taylorimproved this to 67.25 percent and, more recently, Cheer andGoldston increased the percentage to 67.2753. Here we proveby a new method that if the Riemann and Generalized LindelöofHypotheses hold, then at least 70.3704 percent of the zerosare simple and at least 84.5679 percent are distinct. Our methoduses mean value estimates for various functions defined by Dirichletseries sampled at the zeros of the Riemann zeta-function. 1991Mathematics Subject Classification: 11M26. 相似文献
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应用新发展的单一轨迹积分方法求解库仑加线性位的基态量子波函数,得到基态能量和波函数的一般解析表达式,并讨论了解的收敛性.应用此方法讨论了重夸克偶素系统. 相似文献
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This paper concerns a Markov operator T on a space L1, and aMarkov process P which defines a Markov operator on a spaceM of finite signed measures. For T, the paper presents necessaryand sufficient conditions for:
- a the existence of invariant probabilitydensities (IPDs)
- b the existence of strictly positive IPDs,and
- c the existence and uniqueness of IPDs.
- b the existence of strictly positive IPDs,and
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O. Toulemonde F. Studer A. Llobet L. Ranno A. Maignan E. Pollert M. Nevriva E. Pellegrin N.B. Brooks J. Goedkoop 《Journal of magnetism and magnetic materials》1998,190(3):398
X-ray absorption and X-ray magnetic circular dichroism at Mn L2,3- and Nd M4,5-edges of a twinned Nd0.72Ba0.28MnO3 single crystal have been performed versus temperature (between 10 and 300 K) and applied magnetic field (between 0 and 6.5 T). The results show that neodymium cations order below 70 K with the magnetic moments antiparallel to the manganese subnetwork in weak applied magnetic field (<1.5 T). For higher magnetic field, the neodymium moments turn parallel to the manganese ones showing that the antiferromagnetic exchange coupling between both subnetworks is weak. The presence of a metal–insulator transition below 70 K in the studied single crystal correlated to the magnetic ordering of neodymium cations can be understood on the basis of the cation mismatch introduced by barium substitution. 相似文献
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Konings S Schüssler-Langeheine C Ott H Weschke E Schierle E Zabel H Goedkoop JB 《Physical review letters》2011,106(7):077402
We report the direct observation of slow fluctuations of helical antiferromagnetic domains in an ultrathin holmium film using coherent resonant magnetic x-ray scattering. We observe a gradual increase of the fluctuations in the speckle pattern with increasing temperature, while at the same time a static contribution to the speckle pattern remains. This finding indicates that domain-wall fluctuations occur over a large range of time scales. We ascribe this nonergodic behavior to the strong dependence of the fluctuation rate on the local thickness of the film. 相似文献