Dynamical properties of S=1 bond-alternating Heisenberg chains in transverse magnetic fields

We calculate dynamical structure factors of the S=1 bond-alternating Heisenberg chain with a single-ion anisotropy in transverse magnetic fields, using a continued fraction method based on the Lanczos algorithm. In the Haldane-gap phase and the dimer phase, dynamical structure factors show characteristic field dependence. Possible interpretations are discussed. The numerical results are in qualitative agreement with recent results for inelastic neutron-scattering experiments on the S=1 bond-alternating Heisenberg-chain compound $\rm{Ni(C_{9}D_{24}N_{4})(NO_{2})ClO_{4}}$ and the S=1 Haldane-gap compound $\rm{Ni(C_{5}D_{14}N_{2})_{2}N_{3}(PF_{6})}$ in transverse magnetic fields.Comment: 7 pages, 6 figure

FIRST FORMATION OF THIEPINO[2,3-b]- AND THIEPINO[3,2-a]-INDOLIZINE DERIVATIVES

The reactions of potassium 1,3-bis(ethoxycarbonyl)indolizine-2-thiolates with ethyl 4-bromocrotonate afforded the corresponding indolizine derivatives having (E)-(3-ethoxycarbonyl-2-propenyl)thio, (E)- and (Z)-(3-ethoxycarbonyl-1-propenyl)thio group at the 2-position. The alkaline treatment of these S-alkylated indolizines gave the title compounds in good yields.ArticleHETEROCYCLES. 78(2): 319-324 (2009)journal articl

Echo Delay and Overlap with Emitted Orientation Sounds and Doppler-shift Compensation in the Bat, Rhinolophus ferrumequinum

The compensation of Doppler-shifts by the bat, Rhinolophusferrumequinum, functions only when certain temporal relations between the echo and the emitted orientation sound are given. Three echo configurations were used: a) Original orientation sounds were electronically Doppler-shifted and played back either cut at the beginning (variable delay) or at the end (variable duration) of the echo. b) Artificial constant frequency echoes with variable delay or duration were clamped to the frequency of the emitted orientation sound at different Doppler-shifts. c) The echoes were only partially Doppler-shifted and the Doppler-shifted component began after variable delays or had variable durations. With increasing delay or decreasing duration of the Doppler-shifted echo the compensation amplitude for a sinusoidally modulated + 3 kHz Dopplershift (modulation rate 0.08 Hz) decreases for all stimulus configurations (Figs. 1, 2, 3). The range of the Doppler-shift compensation system is therefore limited by the delay due to acoustic travel time to about 4 m distance between bat and target. In this range the overlap duration of the echo with the emitted orientation sound is always sufficiently long, when compared with data on the orientation pulse length during target approach from Schnitzler (1968) (Fig. 5)

Possible Kondo resonance in PrFe4P12 studied by bulk-sensitive photoemission

Pr 4f electronic states in Pr-based filled skutterudites PrT4X12(T=Fe and Ru; X=P and Sb) have been studied by high-resolution bulk-sensitive Pr 3d-4f resonance photoemission. A very strong spectral intensity is observed just below the Fermi level in the heavy-fermion system PrFe4P12. The increase of its intensity at lower temperatures is observed. We speculate that this is the Kondo resonance of Pr, the origin of which is attributed to the strong hybridization between the Pr 4f and the conduction electrons.Comment: 4 pages(camera ready format), 4 figures, ReVTeX

Cross-Sections for Electron Scattering Accompanied by Ionization of Inner-Shells

A method is presented to describe the electron scattering process at an ionization of inner-shell electrons. The differential cross-section with the energy transfer and the momentum transfer is calculated using the expression of the generalized oscillator strength. This cross-section and the total ionization cross-section are fairly close to the results obtained by the Gryzinski equation. The photo-absorption cross-section obtained by the present treatment shows good agreement with the experimental data in a wide range of the photon energy. Based on the present treatment, the scattering angle distribution of the primary electron is calculated

Monte Carlo Simulation of Secondary Electrons in Solids and its Application for Scanning Electron Microscopy

A new Monte Carlo calculation model is introduced to simulate not only the primary electron behavior but also the secondary electron cascade in a specimen bombarded with an electron beam. Either the primary or the generated electron in a specimen having energy greater than 0.1 keV is defined as a fast electron and the single scattering model is used in the simulation which employs the Mott elastic scattering cross section and the Rao Sahib-Wittry energy loss equation. The electron having energy smaller than 0.1 keV is defined as a slow electron and the cascade model is used which takes into account the classical binary collision with the conduction electrons. The performance of this simulation is verified in comparison with experiments for energy and angular distributions of slow secondary electrons (\u3c50eV). Then, this simulation is applied in a discussion of the quantitative signal variation of the secondary and the backscattered electrons depending on a specimen surface topography. The maximum intensity of the secondary electron signal is obtained where the scanning electron beam reaches around 1nm beside the top edge of a surface step made of Cu with the vertical side wall of 500nm in height

A Simulation of Secondary Electron Trajectories in Solids

A Monte Carlo calculation model is introduced to simulate not only the primary electron behavior but also the secondary electron cascade in a specimen bombarded with an electron beam. Electrons having energy greater than 0.1keV are treated as fast electrons and the single scattering Monte Carlo model is adopted. Electrons having energy smaller than 0.1keV are treated as slow electrons and the electron cascade Monte Carlo model is used. The calculated results for the energy distribution of secondary electrons, and primary electron energy dependence of the total secondary yield and the backscattering yield are in good agreement with experimental results