The cross sections of inelastic electron scattering are measured near the threshold of single-pion production by a proton at k2=2.5, 3.5, 5.0 and 8.0 fm? in the polarization range of the virtual photon ?=0.3–0.9. The separation of the |E0+|2 and k2|S0+|2 contributions to the cross-section slope at threshold is carried out and thus a new method of determining the FA and Fπ form factors is realized. The values for the axial mass and mean-square radius of the pion are obtained. 相似文献
We study a class of stationary transport equation with nonlocal low-order tems We obtain the existence and uniqueness of a solution in sobolev spaces 相似文献
The radiative performance of Z-pinches created by the imploding wire array loads is defined by the ablation and implosion dynamics of these loads. Both these processes can be effectively modeled by the Wire Ablation Dynamics Model (WADM), which extends the formalism exploited earlier for the cylindrical wire arrays to the loads of arbitrary geometries. The WADM calculates the ablation rates for each array wire and provides the important dynamic parameters, such as the specific mass and velocity of the imploding plasma, which can be used to estimate the shapes of the x-ray pre-pulse and, partially, the main x-ray burst. The applications of the WADM also extend to combined material wire array loads. The ablation and implosion dynamics of novel Prism Planar Wire Array (PPWA) and combined material (Mo/Al/Mo) Triple Planar Wire Array (TPWA) loads are discussed in detail. The combined WADM and radiation MHD simulation is applied to model the radiative performance of the precursor plasma column, created by the imploding stainless steel compact cylindrical wire array. As the radiation effects intensify with the mass accumulation at the array center, the simulation reveals the transformation of quasi-uniform precursor column into a heterogeneous plasma structure with strong density and temperature gradients. We find that radiative performance of the precursor plasma is greatly affected by the load geometry as well as by the wire material. 相似文献
We present a study of the growth of silver nanoparticles or clusters on a TiO2(1 1 0) substrate in ultra-high vacuum. The growth is monitored in situ by ion and neutral scattering spectroscopy using He+ scattering and Auger spectroscopy. The scattering measurements show that only part of the surface is covered by Ag suggesting formation of clusters. Additionally an ex-situ study was performed by scanning electron microscopy and atomic force microscopy to determine the size distribution of these clusters. The average size distributions were found to range from about 5 to about 20 nm as a function of the evaporation flux. At the higher evaporation flux we observe formation of the smaller sized clusters. 相似文献
Electron transfer processes in the neutralization of Li+ ions on Ag layers grown on Cu(1 1 1) are investigated in quest of quantum confinement effects. Neutralization probabilities in the scattering of Li+ for incident ion energies in the 300 eV to 2 keV range are reported for Ag coverages ranging from 0.15 ML to 5 ML. Results are compared to those for Ag(1 1 1) and Cu(1 1 1) surfaces of bulk crystals. Although existing studies of the characteristics of Ag layers on Cu(1 1 1) indicate significant differences in electronic structure as a function of film thickness, the electron transfer probabilities we measure are found to be very close to those for bulk Ag(1 1 1). These results are commented on the basis of existing models and earlier studies of Li ion neutralization on various metals. 相似文献
The local qualitative robustness of GM-tests against outliers in the autoregression model is studied in the paper. A local scheme of data contamination by independent outliers with the intensity O(n?1/2) is considered. The qualitative robustness in terms of power equicontinuity is obtained. The GM-tests asymptotically optimal in the maximin sense are constructed. 相似文献
α,ω‐Dithiols present an interesting case of molecules with two reactive terminal ‐SH groups (HS‐R‐SH) that allow their use as binders between different metallic entities. They have thus been used in molecular electronics conduction measurements, in “nanogap” electrodes of interest in plasmonics, as building blocks of more complex structures such as metal intercalated superlattices and in the formation of metalized organic thin films, including doped graphene type films. There exist however many problems, because the molecules may end up in undesirable configurations with both thiol terminals bound to the same metal particle/substrate or link with other molecules to produce “multi‐molecule” or “multilayer” structures. This report discusses various key questions on dithiol linking with metal surfaces and the quest of protocols of making problem free dithiol metal structures. It then describes the use of dithiols and their SAMs to produce various metal organic heterostructures useful for molecular electronics and formation of doped metalized organic thin films. We discuss the build up of these structures by self assembly and lithography, their chemical composition and functional properties.