102 research outputs found
Equilibrium structure of monatomic steps on vicinal Si(001)
The equilibrium structure of monatomic steps on vicinal Si(001) is described in terms of anisotropic nearest-neighbor and isotropic second-nearest-neighbor interactions between dimers. By comparing scanning-tunneling-microscopy data and this equilibrium structure, we obtained interaction energies of 0.38 eV between dimers in a row, 0.24 eV between sets of two dimers in adjacent rows, and -0.07 eV for the diagonal interaction between dimers in adjacent rows
Charge-Transfer induced EUV and Soft X-ray emissions in the Heliosphere
We study the EUV/soft X-ray emission generated by charge transfer between
solar wind heavy ions and interstellar H and He neutral atoms in the inner
Heliosphere. We present heliospheric maps and spectra for stationary solar
wind, depending on solar cycle phase, solar wind anisotropies and composition,
line of sight direction and observer position. A time-dependant simulation of
the X-ray intensity variations due to temporary solar wind enhancement is
compared to XMM Newton recorded data of the Hubble Deep Field North observation
(Snowden et al. 2004). Results show that the heliospheric component can explain
a large fraction of the line intensity below 1.3 keV, strongly attenuating the
need for soft X-ray emission from the Local Interstellar Bubble.Comment: 18 pages, 13 figures (5 in online material,for colour figures contact
the authors), 3 tables, accepted in A&
Control of Vortex Pinning in YBCO Thin Films by Incorporating APCs Through Surface Modified Target Approach
The transport of electrical currents in superconductors with much higher efficiency and without any dissipation is considered as the “energy superhighway.” After the discovery of YBa2Cu3O7-δ (YBCO), a high temperature superconductor (HTS), the prospect of using superconducting materials in practical technological applications became very prominent. With much higher Tc (~ 92 K) than conventional low temperature superconductors (LTS), YBCO was considered very promising due to cheaper cooling requirements. The evolution of critical current density (Jc), however, took long time for the material to become useful in practical applications. This was achieved through continuous modification of the processing parameters, deposition of highly oriented thin films on single crystal and buffered metallic substrates and use of artificial pinning centers (APCs) for strong pinning of quantized magnetic vortices. Pulsed laser deposition (PLD) technique is one of the most common and highly efficient techniques for depositing highly oriented YBCO thin films on single crystal and buffered metallic substrates. Using PLD technique, APCs are incorporated into YBCO thin films by many methods which include premixed target method, alternating target method and surface modified target method. In this chapter, the use of surface modified target method to introduce different kinds of APCs into YBCO thin films is presented. These APCs are effective in improving the vortex pinning properties of YBCO thin films for different range of applied magnetic field and its orientation depending upon their geometry and density.Chapter
Room-temperature growth of submonolayers of silicon on Si(001) studied with scanning tunneling microscopy
SELECTIVE ELECTRON-CAPTURE INTO HE-II (N,L) SUBSHELLS IN COLLISIONS OF HE-2+ WITH ATOMIC AND MOLECULAR-HYDROGEN
(N,L)-SUBSHELL ELECTRON-CAPTURE CROSS-SECTIONS IN COLLISIONS OF C-4+, N-5+ AND O-6+ WITH ATOMIC-HYDROGEN
SELECTIVE ELECTRON-CAPTURE INTO HE-II (N,L) SUBSHELLS IN COLLISIONS OF HE-2+ WITH ATOMIC AND MOLECULAR-HYDROGEN
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