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41.
A. M. Petrzhik G. A. Ovsyannikov A. V. Shadrin K. I. Konstantinyan A. V. Zaitsev V. V. Demidov Yu. V. Kislinskii 《Journal of Experimental and Theoretical Physics》2011,112(6):1042-1050
Hybrid herostructures comprising an YBa2Cu3O
x
(YBCO) high-temperature superconductor (HTS) layer and Nb/Au low-temperature superconductor (LTS) bilayer (with critical
HTS and LTS temperatures T
c and T′c, respectively), separated by a thin (d
M = 5–20 nm) interlayer of LaMnO3, La0.7Ca0.3MnO3, or La0.7Sr0.3MnO3 manganite have been studied. The electric resistance and magnetic properties of individual (evaporated directly onto the
substrate) manganite films and related hybrid herostructures have been measured. Based on quasi-classical equations, analytical
expressions for the conductivity of herostructures at T ≤ T′c are obtained in the case of a low-transparency superconductor/manganite interface. It is established that the conductivity
of heterostructures is determined by the proximity effect (related to the penetration of a condensate wavefunction from the
Nb/Au bilayer to manganite) and depends strongly on interface transparency. At low temperatures (T ≪ T
c′), the conductivity peaks are found at voltages determined by the exchange field of the manganite interlayer. At T
c′ < T < T
c, conductivity features at nearly zero bias voltages are observed, which are related to the superconductivity of the YBCO
electrode. 相似文献
42.
Leif Holmlid 《Journal of nanoparticle research》2011,13(10):5535-5546
The inter-atomic distances in potassium clusters of Rydberg matter (RM) at excitation levels n
B = 4–8 were recently measured by phase-delay spectroscopy (Holmlid, J Nanopart Res 12: 273, 2010). Excitation levels n
B < 4 with shorter inter-atomic distances exist for hydrogen clusters, and distances down to 140 pm are now measured with this
light-scattering method. The clusters studied have maximum dimensions from 0.3 nm up to several tens of nm, often being planar.
A weak carbon dioxide laser beam interacts with the clusters in a tunable RM cavity. A strong fringe structure is observed
as a function of the end-grating angular position. Delay lengths in the clusters are derived from the fringe structure, corresponding
to twice the distance between rows or planes in the clusters. Good agreement with predicted and a few previously measured
distances in excitation levels n
B = 1, 2, and 3 is found. Close-packing is the main structure both in planar and 3D clusters. Planar clusters are only observed
for n
B = 1 and 3, while 3D clusters are found in excitation levels n
B = 1, 2 and 3. The cluster–cluster distance in stacks of planar clusters for n
B = 2 and 3 is now observed for the first time. 相似文献
43.
44.
The valence band electronic structure of Pr0.5Sr0.5MnO3 has been investigated across its paramagnetic metallic (PMM)–ferromagnetic metallic (FMM)–antiferromagnetic insulator (AFMI) transition. Using surface sensitive high resolution photoemission we have conclusively demonstrated the presence of a pseudogap of magnitude 80 meV in the near Fermi level electronic spectrum in the PMM and FMM phases and finite intensity at the Fermi level in the charge ordering (CO)-AFMI phase. The pseudogap behavior is explained in terms of the strong electron–phonon interaction and the formation of Jahn Teller (JT) polarons, indicating the charge localizations. The finite intensity at the Fermi level in the insulating phase showed a lack of charge ordering in the surface of the Pr0.5Sr0.5MnO3 samples. 相似文献
45.
Kristian Berland 《Superlattices and Microstructures》2011,50(4):411-418
A general, system-independent, formulation of the parabolic Schrödinger–Poisson equation is presented for a charged hard wall in the limit of complete screening by the ground state. It is solved numerically using iteration and asymptotic boundary conditions. The solution gives a simple relation between the band bending and sheet charge density at an interface. Approximative analytical expressions for the potential profile and wave function are developed based on properties of the exact solution. Specific tests of the validity of the assumptions leading to the general solution are made. The assumption of complete screening by the ground state is found be a limitation; however, the general solution provides a fair approximate account of the potential profile when the bulk is doped. The general solution is further used in a simple model for the potential profile of an AlN/GaN barrier structure. The result compares well with the solution of the full Schrödinger–Poisson equation. 相似文献
46.
The objective of this study was to create a thin film optode for fast pH measurements that meets the requirements for imaging pH-responses from cells as well as for a future hybrid design for detection of multiple analytes simultaneously. The sensor is based on the covalent attachment of 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) to a film forming cellulose acetate material through a sulfonamide linkage. The synthesis routes of the cellulose material and regio-specific covalent attachment of the dye are described in detail. The sensor was sterilized in two different ways and showed excellent biocompatibility with Chinese hamster ovary cells. Imprints from cells and μm thin cell extensions were visualized when altering pH of the surrounding solution. The sensor was tested together with time-dependent sigmoidal calibrations giving pH determinations with an exceptional precision and accuracy during measurement within pH 6-8. The precision of the optode, calculated as pooled S.D. (n = 8) according to IUPAC recommendations between pH 6.641 and 7.742 was 0.0029. The accuracy was significantly better than the electrode used as reference during the measurements. The response time (0-95%) was 100 s between pH 6.641 and 7.742 and the reverse response (95-0%) was 80 s. The sensor shows great potential for extra-cellular pH determination over time during cell growth and pharmacological exposure. 相似文献
47.
A set of new voltage stabilizers has been synthesized, tested and has shown to suppress a degradation mechanism, i.e. electrical treeing, present in cross-linked polyethylene used for high-voltage cables. Electrical treeing is seen at very high and divergent electrical fields and has a rapid lapse from initiation to total breakdown of the insulation material. The new voltage stabilizers presented in this paper have increased the electrical tree inception field with up to 50% at such low additions as 0.4%-wt. Furthermore, the best-performing materials have also proven to increase the threshold level for tree inception, i.e. before this level no deterioration of the material is seen, up to 50%. 相似文献
48.
This paper presents a systematic X‐ray photoelectron spectroscopy (XPS)study of the Ni silicides Ni3Si, Ni31Si12, Ni2Si, NiSi and NiSi2 produced by annealing of sputtered thin films. The in situ XPS study focuses on both the core level peaks and Auger peaks. The peak positions, shapes, satellites as well as Auger parameters are compared for different silicides. The factors that influence the Ni core level peak shifts are discussed. The Ni 2p3/2 peak shape and satellites are correlated with the valence band structure. The effect of argon ion etching on surface composition and chemical states is also investigated. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
49.
Johan H. Tykesson 《Journal of Theoretical Probability》2009,22(2):402-417
We consider the Poisson Boolean model of continuum percolation on a homogeneous space M. Let λ be the intensity of the underlying Poisson process. Let λ u be the infimum of the set of intensities that a.s. produce a unique unbounded component. First we show that if λ>λ u , then there is a.s. a unique unbounded component at λ. Then we let M=?2×? and show that at λ u there is a.s. not a unique unbounded component. These results are continuum analogs of theorems by Häggström, Peres and Schonmann. 相似文献
50.
Vladimir Fal’ko Andre Geim Sankar Das Sarma Allan MacDonald Philip Kim 《Solid State Communications》2009,149(27-28):1039-1040