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排序方式: 共有462条查询结果,搜索用时 15 毫秒
101.
An obvious weak localization correction to anomalous Hall conductance(AHC) in very thin CoFeB film is reported.We find that both the weak localization to AHC and the mechanism of the anomalous Hall effect are related to the CoFeB thickness.When the film is thicker than 3 nm,the side jump mechanism dominates and the weak locaUzation to AHC vanishes.For very thin CoFeB films,both the side jump and skew scattering mechanisms contribute to the anomalous Hall effect,and the weak localization correction to AHC is observed. 相似文献
102.
B. Lee Roberts 《中国物理 C》2010,34(6):741-744
The New Muon (g-2) Collaboration at Fermilab has proposed to measure the anomalous magnetic moment of the muon, αμ, a factor of four better than was done in E821 at the Brookhaven AGS, which obtained αμ = [116592089(63)] × 10^-11 ±0.54 ppm. The last digit of a, is changed from the published value owing to a new value of the ratio of the muon-to-proton magnetic moment that has become available. At present there appears to be a difference between the Standard-Model value and the measured value, at the ≌ 3 standard deviation level when electron-positron annihilation data are used to determine the lowest-order hadronic piece of the Standard Model contribution. The improved experiment, along with further advances in the determination of the hadronic contribution, should clarify this difference. Because of its ability to constrain the interpretation of discoveries made at the LHC, the improved measurement will be of significant value, whatever discoveries may come from the LHC. 相似文献
103.
A model of a degenerate gas consisting of neutrons that are in chemical equilibrium with degenerate protons and electrons in a stationary and homogeneous superstrong magnetic field is used to describe the state of the matter in central regions of strongly magnetized neutron stars. Expressions for thermodynamic quantities (such as energy density, particle density, pressure, and magnetization) characterizing a degenerate gas of neutrons, protons, and electrons are obtained. In these expressions, the contributions determined by the interaction between anomalous magnetic moments of fermions and the magnetic field are taken into account. Macroscopic effects that may occur in strongly magnetized neutron stars are discussed. We show that all thermodynamic quantities characterizing electrically charged fermions in a strong magnetic field are subject to nonperiodic oscillations caused by the interaction of the anomalous magnetic moments of protons and electrons with the magnetic field. We also show that if the nucleon density and the electron density exceed threshold values that are relatively small and depend on the magnetic field strength, all fermions are fully polarized with respect to the spin. The full spin polarization effect in neutrons is caused by the interaction between the anomalous magnetic moment and the magnetic field. The obtained results may prove useful in understanding processes that occur in the nucleus of a neutron star with a magnetic field frozen into the star. 相似文献
104.
Synthesis via organo-lithium compounds is reviewed. An anomalous aromatic substitution via halogen-metal exchange is described.
Here, the substitution does not occur at the position where the halogen was present; but at an alternate position. A mechanism
is advanced, in which the halogen-metal exchange is proposed as being faster than the hydrogen(acidic)-metal exchange. 相似文献
105.
S. Narayanaswami S. Rajeswari B. R. Pai K. Nagarajan W. J. Richter S. J. Shenoy 《Journal of Chemical Sciences》1984,93(2):145-155
Solutions of 3,4-dihydro-6,7-methylenedioxyisoquinoline (1) and analogues2–5 and9 as well as isoquinolines7 and8 in certain samples of CDCl3, CCl4, DMSO-d6 or acetone-d6 gave rise to anomalous1Hnmr spectra with extreme line broadening, signals due to protons at C-l and C-3 most often not being seen. The spectra of1 and3 were most striking in this respect.1Hnmr spectra of the quaternary salt10 and the model schiff base11 were normal. Several hypotheses for the observed line broadening have been considered and rejected, a slow equilibrium1 ⇆13 being one of them. NaBH4 reduction of1 and2 followed by mass spectrometric analysis of the crude tetrahydroisoquinolines16 and17 ruled out a slow equilibrium1 ⇆14 and2 ⇆15 as contributory cause for line broadening. The crude reduction products unexpectedly contained N-ethyl species22 and25. Their formation is rationalised 相似文献
106.
107.
Tatsuro Otaki 《Optical Review》2000,7(2):119-122
A new phase contrast microscopy technique for halo reduction is proposed. This technique is based on an apodization method combined with the Zernike phase contrast method. Although it has been a difficult theoretical problem, the proposed technique achieves halo reduction by considering angles of diffraction and phase differences. The technique utilizes an apodized phase plate consisting of a quarter wave phase shift ring with a 25% transmittance, and a pair of adjacent rings, which have 50% transmittance. This element is placed at the back focal plane of the objective. The result is startling, halo reduced images of phase objects providing enhanced inner details. 相似文献
108.
Anomalous diffusion in fractal porous medium 总被引:1,自引:0,他引:1
王子亭 《应用数学和力学(英文版)》2000,21(10):1145-1152
IntroductionAnumberoffielddatahaveshownthatmanykindsofporousmediasystemhavedifferentkindsofheterogeneousstructureindifferentscale.Theseheterogeneousstructureassociatewitheachotherandhavesomekindsofself_similarityandwecallthiskindporousmediaasfractalp… 相似文献
109.
分形多孔介质和均质多孔介质相比具有许多特殊的性质,它在各个不同的尺度上有相互钳套的自相似结构.孔隙分形中的粒子扩散和经典的Fick扩散不同,其均方位移服从分形幂律关系.据此对孔隙分形中的粒子扩散利用随机过程的统计方法建立了奇异扩散的理论模型,讨论了奇异扩散的非马尔可夫性质和分形性质. 相似文献
110.
Ab initio calculations of chloride complexes of Au, Hg, Tl, Pb, and Bi in anomalous oxidation states (2S1/2 electron state) were carried out by the Becke-Lee-Yang-Parr density functional method using the Dunning-Hay LanL2DZ basis
set. Optimum geometric parameters and electronic characteristics of MCl
n
(H2O)
m
n
(n=1–4 andm=0,4,5) complexes were determined. In each of the considered series the spin, population on the central metal atom decreases
as its atomic number increases. The energy of transition of the unpaired electron to the lowest unoccupied MO decreases in
the same order. The unpaired electron occupies an orbital that is mostly a linear combination of the s-orbital of the metal
atom and the p-orbital of the Cl atom (the antibonding σ-orbital of the M−Cl bond). Distinctions in the changes in spectral
properties of aquacomplexes and chloride complexes in isoelectronic series, observed as the degree of oxidation of the metal
atom increases, were explained. The results of calculations are in agreement with the experimental data obtained by ESR and
optical spectroscopy.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1049–1055, June, 1999. 相似文献