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41.
We give a lattice construction of the discretizations of the topologically nontrivial maps S
2n–1S
n
. For n=1, 2, 4, 8, these are the Hopf maps. The construction, based on Barnes-Wall lattices, Reed-Muller error-correcting codes, and Hadamard matrices, generalizes to n=2
i
for i any integer. Manton's result for the cases n=2 and 4 (i.e., the monopole and instanton) are included. We argue that discrete harmonic analysis will be exact in the infinite dimension limit.Work supported in part by the DOE contract #DE-ACO2-87ER-40325.B.Department of Energy Outstanding Junior Investigator supported in part by DOE contract number DE-FGO5-85ER-40226. 相似文献
42.
43.
L.W. Grossman G.S. Hurst S.D. Kramer M.G. Payne J.P. Young 《Chemical physics letters》1977,50(2):207-209
Laser techniques for the production of free atoms at time t = 0 and their detection at r > 0 have been developed to measure the diffusion of Cs atoms in Ar and the reaction of Cs with O2 in Ar gas. 相似文献
44.
The francium atom offers an excellent laboratory to study electron-nucleus interactions. As the heaviest alkali, its atomic
properties can be calculated with high precision, and laser trapping methods now allow precision optical spectroscopy of many
isotopes. Recent measurements of the 7P1/2 hyperfine structure, when coupled with previous measurements of the ground state hyperfine structure reveal a hyperfine anomaly.
The change in anomaly between an even-N isotope and an odd-N isotope is sensitive to the radial distribution of the neutron magnetization.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
45.
V. G. Grossman B. G. Bazarov K. N. Fedorov Zh. G. Bazarova 《Russian Journal of Applied Chemistry》2010,83(6):1074-1076
The possibility of ternary molybdates of compositions Tl5LnHf(MoO4)6 (5 : 1 : 2) (Ln = Dy-Lu), TlLnHf0.5(MoO4)3 (1 : 1 : 1) (Ln = Ce-Nd), and Tl2LnHf2(MoO4)6.5 (2 : 1 : 4) (Ln = Dy-Lu) was investigated by a method of solid state reactions. A temperature dependence of electrical conductivity
in the temperature range 200–500°C was studied. 相似文献
46.
New physics contributions to Bs-Bs mixing can be parametrized by the size (rs2) and the phase (2thetas) of the total mixing amplitude relative to the standard model amplitude. The phase has so far been unconstrained. We first use the D0 measurement of the semileptonic CP asymmetry ASL to obtain the first constraint on the semileptonic CP asymmetry in Bs decays, ASLs=-0.008+/-0.011. Then we combine recent measurements by the CDF and D0 Collaborations--the mass difference (DeltaMs), the width difference (DeltaGammas), and ASL;s--to constrain 2thetas. The errors on DeltaGammas and ASL;s should still be reduced to have a sensitive probe of the phase, yet the central values are such that the regions around 2thetas approximately 3pi/2 and, in particular, 2thetas approximately pi/2, are disfavored. 相似文献
47.
Konstantin Nikolic Nir Grossman Matthew S. Grubb Juan Burrone Chris Toumazou Patrick Degenaar 《Photochemistry and photobiology》2009,85(1):400-411
Recent developments have used light-activated channels or transporters to modulate neuronal activity. One such genetically-encoded modulator of activity, channelrhodopsin-2 (ChR2), depolarizes neurons in response to blue light. In this work, we first conducted electrophysiological studies of the photokinetics of hippocampal cells expressing ChR2, for various light stimulations. These and other experimental results were then used for systematic investigation of the previously proposed three-state and four-state models of the ChR2 photocycle. We show the limitations of the previously suggested three-state models and identify a four-state model that accurately follows the ChR2 photocurrents. We find that ChR2 currents decay biexponentially, a fact that can be explained by the four-state model. The model is composed of two closed (C1 and C2) and two open (O1 and O2) states, and our simulation results suggest that they might represent the dark-adapted (C1-O1) and light-adapted (C2-O2) branches. The crucial insight provided by the analysis of the new model is that it reveals an adaptation mechanism of the ChR2 molecule. Hence very simple organisms expressing ChR2 can use this form of light adaptation. 相似文献
48.
Several surface analytical techniques, including electron spectroscopy for chemical analysis (ESCA)(X-ray photoelectron spectroscopy) and sputtered neutral mass spectrometry (SNMS), were used to study the interaction between Hg and other components of fluorescent lamps, a very critical issue in lighting industries. Active sites, responsible for Hg interaction/deposition, can be successfully identified by comparing the x- y distribution (obtained by ESCA mapping) and depth distribution (available through SNMS) of respective lamp components with that of Hg. A correlation in both depth and x- y distribution is strong evidence of site preference for Hg interaction/deposition. A burial mechanism is, however, proposed when only depth distribution, not x- y, is correlated. Other modes of ESCA (high resolution, angle-resolved, etc.) were also helpful. Information about the valence states of the interacted Hg species would help to define the nature of the interaction. 相似文献
49.
A PC based system has been developed for the analysis of gamma-ray spectra and for the complete reduction of data from INAA experiments, including software to average the results from multiple lines and multiple countings and to produce a final report of analysis. Graphics algorithms may be called for the analysis of complex spectral features, to compare the data from alternate photopeaks and to evaluate detector performance during a given counting cycle. A database of results for control samples can be used to prepare quality control charts to evaluate long term precision and to search for systematic variations in data on reference samples as a function of time. The entire software library can be accessed through a user-friendly menu interface with internal help. 相似文献
50.
Ch. de la Vaissière H. Muirhead S. N. Ganguli Ph. Gavillet M. Mazzucato C. Dionisi R. Blokzijl J. C. Kluyver G. F. Wolters E. W. Kittel M. Zralek B. Foster P. Grossman 《Zeitschrift fur Physik C Particles and Fields》1979,1(1):3-17
We have investigated the properties of off-shell \(\bar K\) K and \(\bar p\) p annihilations into pions by using the interactionsK ? p → Λ + pions at 4.2 GeV/c. The properties considered are multiplicities, hadronic temperatures and angular distributions. These properties appear more akin to those of \(\bar p\) p annihilations in flight than to that of \(\bar p\) p annihilation at rest despite the fact that the annihilation energy is small. 相似文献