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91.
M. Mayr K. -H. Speidel M. Knopp W. Karle T. Faestermann F. Hagelberg H. -J. Simonis P. N. Tandon J. Gerber 《Zeitschrift für Physik A Hadrons and Nuclei》1987,327(2):157-161
[Theg-factor ratio of the first excited 3? and 5? states in40Ca was measured to beg 3/g 5=1.01(10) employing the implantation perturbed angular correlation technique. The static hyperfine fields (SF) in Fe and Gd hosts were used. In addition the lifetime of the 5? state was measured to be τ=426(7)ps. The values of the SF in Gd and Fe hosts were deduced and compared with systematics in this element region. 相似文献
92.
Litharge, the red tetragonal form of lead oxide α-PbO and massicot, the yellow orthorhombic form β-PbO, are synthesized from
lead(II) salts in aqueous media at elevated temperatures. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were
used to characterize the size, morphology, and crystallographic structural forms of the products. The role of impurities in
the experimental synthesis of the materials and microstructural variations in the final products are described. The implications
of these observations regarding the synthesis of different conducting lead oxides and other related materials are discussed.
PACS 71.20.Ps; 72.80.Jc; 74.62.Bf; 74.62.Dh; 75.50.Tt 相似文献
93.
We theoretically investigated the mass dependence of the sympathetic cooling rate of gas-phase ions trapped in a linear radio-frequency-quadrupole
ion trap. Using an a priori molecular dynamical calculation, tracing numerically with Newtonian equations of motion, we found
that ions with a mass greater than 0.54±0.04 times that of the laser-cooled ions are sympathetically cooled; otherwise, they
are heated. To understand the mass dependence obtained using the molecular-dynamical calculation, we made a heat-exchange
model of sympathetic cooling, which shows that the factor of 0.54±0.04 is a consequence of absence of micro-motion along the
axis of the linear ion trap.
Received: 10 December 2001 / Revised version: 28 January 2002 / Published online: 14 March 2002 相似文献
94.
Alp E. E. Sturhahn W. Toellner T. S. Zhao J. Hu M. Brown D. E. 《Hyperfine Interactions》2002,144(1-4):3-20
Nuclear resonant inelastic X-ray scattering of synchrotron radiation is being applied to ever widening areas ranging from
geophysics to biophysics and materials science. Since its first demonstration in 1995 using the 57Fe resonance, the technique has now been applied to materials containing 83Kr, 151Eu, 119Sn, and 161Dy isotopes. The energy resolution has been reduced to under a millielectronvolt. This, in turn, has enabled new types of
measurements like Debye velocity of sound, as well as the study of origins of non-Debye behavior in presence of other low-energy
excitations. The effect of atomic disorder on phonon density of states has been studied in detail. The flux increase due to
the improved X-ray sources, crystal monochromators, and time-resolved detectors has been exploited for reducing sample sizes
to nano-gram levels, or using samples with dilute resonant nuclei like myoglobin, or even monolayers. Incorporation of micro-focusing
optics to the existing experimental setup enables experiments under high pressure using diamond-anvil cells. In this article,
we will review these developments.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
95.
P. Paasche T. Valenzuela D. Biswas C. Angelescu G. Werth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):295-300
We have examined experimentally the motional spectrum of an electron cloud confined in a Penning trap. When the axial oscillation
is excited by a radio frequency field the resonance exhibits a double structure. Both components depend differently on the
number of trapped electrons and have different shape and width. We conclude that one of them corresponds to the excitation
of the individual electrons while the other is the center-of-mass mode of the cloud. The threshold behaviour of the center-of-mass
resonance suggests that it is a parametric instability of a Mathieu type equation of motion.
Received 11 July 2001 and Received in final form 12 November 2001 相似文献
96.
97.
98.
T. V. Maslova 《Russian Journal of Mathematical Physics》2006,13(4):425-430
The results obtained in V. P. Maslov’s article [1] can automatically be carried over to arbitrary semiotic systems if the
string of signs is sufficiently long. We shall show in this article, by using arguments based on the ideas of Kolmogorov complexity
and by applying the theorem of V. P. Maslov from [2], that one can obtain similar formulas for the distribution of various
semiotic objects. In order to do this, we must introduce notions generalizing the occurrence frequency of words in corpora
of texts. We also interpret a formula due to Maslov (appearing in [3]) from the point of view of the general semiotic notions
introduced here. 相似文献
99.
T. Bernhard 《Surface science》2006,600(9):1877-1883
The structure and magnetism of thin epitaxial Fe layers grown on Cu(0 0 1) is investigated by grazing scattering of fast H and He atoms. Information on the atomic structure of the film and substrate surfaces is obtained by making use of ion beam triangulation with protons. The magnetic behavior is studied via the polarization of light emitted after capture of spin-polarized electrons into excited atomic terms during scattering of He atoms. For the formation of bcc(1 1 0)-like Fe films at higher coverages, we detect differences in structural and magnetic properties for room and low temperature growth. We suggest that the crystalline structure depends on the film morphology and that Cu impurities affect the magnetic properties. 相似文献
100.
方永得 张玉虎 M.Oshima Y.Toh 周小红 M.Koizumi A.Osa A.Kimura Y.Hatsukawa T.Morikawa M.Nakamura M.Sugawara H.Kusakari 《中国物理 C》2006,30(2):99-104
利用在束γ谱学实验技术, 通过173Yb(19F,4nγ)反应
布居了188Au的高自旋态, 并对其准粒子带结构进行了研究. 基于实验测量结果, 对原有的双奇核188Au能级纲图做了较大的修改. 通过系统性比较, 对15+以上的能级结构进行了讨论. 相似文献