Influence of magnetic field on acoustic emission in dislocation-containing silicon under current loading

The influence of weak (<1 T) magnetic fields on acoustic emission (AE) of dislocation-containing n-Si(111) under current loading j=(1?5)×10⁵ A/m² is investigated. It is found that the combined effect of the magnetic and electric fields leads to an increase in the acoustic emission response by a factor of 1.5 and is responsible for the emergence of an additional peak in the AE spectra at a frequency of 1.7–1.8 Hz. The result is explained by the influence of magnetic fields, which changes the energy state of paramagnetic stoppers. This facilitates the separation and motion of dislocations. Withdrawal of the magnetic field leads to the relaxation of acoustic emission processes, which is determined by the dynamics of excited point centers interacting with a dislocation.     

Combining a langevin description of heavy-ion induced fission including neutron evaporation with the statistical model

A model is developed which combines dynamical (Langevin-) calculations with the Kramers modified statistical model in order to describe heavy-ion induced fission including neutron evaporation. In the example of the¹⁹F+¹⁸¹Ta collision, the energy dependence of fission probabilities, neutron multiplicities and (H.I.,xn)-cross sections is calculated and a fair agreement with the data is achieved with a reduced friction parameter ofβ=3^*10²¹sec^?1. We pay particular attention to the angular momentum dependence of the fusion-fission process.     

Synthesis of 1-functionalized imidazo[1,5-а]pyrazolo[5,1-с]pyrazines

Chemistry of Heterocyclic Compounds - 4-Chloropyrazolo[1,5-a]pyrazines react with ethyl isocyanoacetate to form ethyl imidazo[1,5-a]pyrazolo[5,1-c]pyrazine-1-carboxylates, hydrolysis of which...     

On Padé approximants of Markov-type meromorphic functions

The paper is devoted to the asymptotic properties of diagonal Padé approximants for Markov-type meromorphic functions. The main result is strong asymptotic formulas for the denominators of diagonal Padé approximants for Markov-type meromorphic functions f = \(\hat \sigma \) + r under additional constraints on the measure σ (r is a rational function). On the basis of these formulas, it is proved that, in a sufficiently small neighborhood of a pole of multiplicity m of such a meromorphic function f, all poles of the diagonal Padé approximants f _n are simple and asymptotically located at the vertices of a regular m-gon.     

Vibrational Raman spectra of CdSx Se1‐x magic‐size nanocrystals

Resonant Raman scattering spectra of ultrasmall (<2 nm) magic‐size nanocrystals (NCs) are reported. The spectra of CdS and CdS_x Se_1‐x NCs, resonantly excited with 325 nm and 442 nm laser lines, correspondingly, reveal broad features in the range of bulk optical phonons. The relatively large width, ～50 cm^‐1, and downward shift, ～20 cm^‐1, of the Raman bands with respect to the longitudinal optical phonon in bulk crystals and large NCs are discussed based on the breaking of the translational symmetry and bond distortion in these ultrasmall NCs. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Regioselective and Scalable Total Synthesis of Licochalcone C and Related Licoagrochalcones

A novel efficient method for the synthesis of licochalcone C in good yield on up to 30 g scale was developed. The reaction sequence included relied on the directed ortho-metalation (DOM) of bis-O-MOM-protected resorcinol for the regioselective C-prenylation, followed by metalation-formylation, selective O-deprotection of a hydroxyl group located between the formyl and prenyl groups, its methylation, and aldol reaction with p-hydroxyacetophenone. Synthesis of structurally related retrochalcones, i.e., licoagrochalcones B, C, and D, was also proposed.     

Interior continuity,continuity up to the boundary,and Harnack's inequality for double-phase elliptic equations with nonlogarithmic conditions

We prove continuity and Harnack's inequality for bounded solutions to elliptic equations of the type under the precise choice of μ.