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1.
Results from Super-Kamiokande-I’s entire 1496 live days of solar neutrino data are presented, including the absolute flux,
energy spectrum, zenith angle (day/night) and seasonal variation. The possibility of MSW and vacuum oscillations is discussed
in light of these results. Results from the first 1289 days of Super-K-I’s atmospheric neutrino analysis are also presented,
including the evidence for νμ →ν
τ oscillations, against νμ → νsterile oscillations, and the current limits on proton decay. Finally, results based on 56 × 1019 protons on target are given for the K2K long-baseline neutrino oscillation experiment. 相似文献
2.
Jung JC Kache R Vines KK Zheng YS Bijoy P Valluri M Avery MA 《The Journal of organic chemistry》2004,69(26):9269-9284
A convergent, total synthesis of epothilones B (2) and D (4) is described. The key steps are Normant coupling to establish the desired (Z)-stereochemistry at C12-C13, Wadsworth-Emmons olefination of methyl ketone 28 with the phosphonate ester 8, diastereoselective aldol condensation of aldehyde 5 with the enolate of keto acid derivatives to form the C6-C7 bond, selective deprotection of acid 52, and macrolactonization. 相似文献
3.
The observation of Scholte-like ultrasonic waves travelling along the water-loaded surfaces of solids with periodically varying properties is reported. Results are presented for two 2D superlattices that intersect the surface normally: a laminated solid of alternating 0.5 mm thick layers of aluminium and a polymer, and a hexagonal array of polymer rods of lattice spacing 1 mm in an aluminium matrix. The surface waves are generated and detected by line-focus acoustic lenses aligned parallel to each other, and separated by varying distances. For homogeneous solids, phase matching constraints do not allow the Scholte wave to be coupled into with an experimental configuration of this type, and this is demonstrated with results on a uni-directional carbon-fibre/epoxy composite. These constraints are relaxed for a periodic solid, where coupling takes place through Umklapp processes. In our experiments, the source pulse is fairly broadband, extending up to about 6 MHz, whereas the spectrum of the observed Scholte arrival is peaked at around 4 MHz. We attribute this to a resonance in the surface response of the solid associated with the superlattice structure. On rotating the solid about its surface normal, the Scholte wave displays a characteristic variation in phase arrival time and, to a lesser extent, also group arrival time. This variation is well accounted for with a model that incorporates Umklapp processes in the solid's surface response. 相似文献
4.
5.
John D. Williams Xiaoyuan Ding Son Nguyen Kimberly K. Vines Norton P. Peet 《合成通讯》2013,43(14):1974-1979
6-Cyanobenzo[b]furan-2-boronic acid pinacol ester (10) is a potentially useful two-point scaffold for the construction of specific compounds or compound libraries with benzofuran cores. Using a per-iodination/de-iodination strategy coupled with Sonogashira alkynylation and Cu-catalyzed heteroannulation, we have developed a procedure that allows the preparation of benzo[b]furan-6-carbonitrile (9) and 6-cyanobenzo[b]furan-2-boronic acid pinacol ester (10) in gram quantities. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
6.
Rare earth element substituted bismuth ferrites (BiFeO3) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi
x
La1−x
FeO3 (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of
these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz
to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz).
All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature
shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds
to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity
as well as ε′ are found to be maximum for the sample x=0.2 at room temperature. 相似文献
7.
CoFe2O4-BaTiO3 composites were prepared using conventional ceramic double sintering process with various compositions. Presence of two phases
in the composites was confirmed using X-ray diffraction. The dc resistivity and thermoemf as a function of temperature in
the temperature range 300 K to 600 K were measured. Variation of dielectric constant (ɛ′) with frequency in the range 100 Hz to 1 MHz and also with temperature at a fixed frequency of 1 kHz was studied. The ac
conductivity was derived from dielectric constant (ɛ′) and loss tangent (tan δ). The nature of conduction is discussed on the basis of small polaron hopping model. The static value of magnetoelectric
conversion factor has been studied as a function of magnetic field. 相似文献
8.
9.
Reeta Vyas Justin Vines Surendra Singh 《量子光学学报》2006,12(B08):64-64
Fluctuations of light provide a window on the underlying quantum dynamical evolution of the source emitting light. Emission of a photon by a source signals quantum fluctuations in progress. Hence a measurement that is conditioned upon a photodetection allows us to follow the time evolution of the fluctuations and the framework of conditioned measurements provides a powerful conceptual tool for understanding nonclassical features of quantum dynamics. We discuss the connection between quantum dynamics and photon fluctuations in terms of conditional measurements of intensity and field quadratures of light from a single atom in an optical cavity. Using the Fokker- Planck equation for a single atom in a high-Q cavity, we describe the light from the cavity in terms of Gaussian random variables and a coherent component. These are used to study conditional measurements of intensity and quadrature squeezing. It is found that when the coherent component is completely removed conditional light intensity shows large fluctuations, whereas conditional squeezing exhibits strong nonclassical behavior. Indeed both field quadratures exhibit nonclassical behavior. On the other hand a small coherent component results in a sizable reduction in intensity fluctuations and small squeezing. 相似文献
10.
David L Kirkham Laura KK Pacey Michelle M Axford Roberta Siu Daniela Rotin Laurie C Doering 《BMC neuroscience》2006,7(1):50-9