Electromagnetic acceleration of the Belousov-Zhabotinski reaction

Acceleration of the Belousov-Zhabotinski (BZ) reaction, in stirred homogeneous solutions, by low frequency electromagnetic (EM) fields has provided new insights into EM interaction mechanisms. The acceleration varies inversely with the basal reaction rate, indicating that the applied magnetic field and the intrinsic chemical driving forces affect the same electron transfer reaction. The amplitude and frequency dependence of the EM field interactions are also consistent with interaction during electron transfer. A mechanism based on interaction with moving electrons offers a way of explaining the ability of EM fields to stimulate gene expression, in particular the stress response, since electrons have been shown to move in DNA.     

Method of Eliminating Systematic Errors of Atomic Absorption Analysis in Atomization of a Material in a Graphite Furnace

By taking as an example the obtaining of the spectra of the gas phase over alkali metal iodides and calcium fluoride, we show the possibility of eliminating systematic errors of atomic absorption analysis which are due to nonselective absorption of light. It is been suggested that it makes sense to create a database that would contain molecular absorption spectra of the most abundant substances and would be intended for use by chemistsanalysts.     

Production of heavy neutron-rich nuclei “south" of lead

The production of heavy neutron-rich nuclei is investigated using cold-fragmentation reactions. More than 25 new heavy neutron-rich nuclei were produced in the fragmentation of ²⁰⁸Pb projectiles at 1 A GeV impinging a beryllium target. The precise measurement of their production cross sections enables to benchmark the predictive power of different model calculations and make reliable predictions of the production rates expected in future radioactive beam facilities.     

Iterative Algorithms for Multiscale State Estimation, Part 2: Numerical Investigations

Usually, direct methods are employed for the solution of linear systems arising in the context of optimization. However, motivated by the potential of multiscale refinement schemes for large problems of dynamic state estimation, we investigate in this paper the application of iterative solvers based on the concepts developed in Ref. 1. Specifically, we explore the effect of different system reductions for various Krylov-space iteration methods as well as three concepts of preconditioning. The first one is the normalization of states and outputs, which also favors error analysis. Next, diagonal scale-dependent preconditioners are compared; they all bound the condition numbers independently of the refinement scale, but exhibit significant quantitative differences. Finally, the effect of the regularization parameter on condition numbers and iteration numbers is analyzed. It turns out that a so-called simplified Uzawa scheme with Jacobi preconditioning and suitable regularization parameter is most efficient. The experiments also reveal that further improvements are necessary.     

Breather Solutions in Periodic Media

For nonlinear wave equations existence proofs for breathers are very rare. In the spatially homogeneous case up to rescaling the sine-Gordon equation \({\partial^2_t u = \partial^2_x u - \sin (u)}\) is the only nonlinear wave equation which is known to possess breather solutions. For nonlinear wave equations in periodic media no examples of breather solutions have been known so far. Using spatial dynamics, center manifold theory and bifurcation theory for periodic systems we construct for the first time such time periodic solutions of finite energy for a nonlinear wave equation

$ s(x) \partial^2_t u(x,t) = \partial^2_x u(x,t) - q(x) u(x,t)+ r(x)u(x,t)^3, $

with spatially periodic coefficients s, q, and r on the real axis. Such breather solutions play an important role in theoretical scenarios where photonic crystals are used as optical storage.

     

Direct observation of two protons in the decay of 54Zn

The two protons emitted in the decay of 54Zn have been individually observed for the first time in a time projection chamber. The total decay energy and the half-life measured in this work agree with the results obtained in a previous experiment. Angular and energy correlations between the two protons are determined and compared to theoretical distributions of a three-body model. Within the shell model framework, the relative decay probabilities show a strong contribution of the p2 configuration for the two-proton emission. After 45Fe, the present result on 54Zn constitutes only the second case of a direct observation of the ground state two-proton decay of a long-lived isotope.     

Synthesis of 2′-Iodo Analogues of β-Rhodomycins1

Abstract

10-O-(R/S)Tetrahydropyranosyl-β-rhodomycinone (5a,b) was prepared via 7,9-O-phenylboronyl-β-rhodomycinone (3) from β-rhodomycinone (1). Glycosidation of 5a,b with 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol (3,4-di-O-acetyl-L-rhamnal) (6) and 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-lyxo-hex-1-enitol (3,4-di-O-acetyl-L-fucal) (7) using N-iodosuccinimide gave the corresponding 7-O-glycosyl-β-rhodomycinones 8a,b, 9a,b and 10a,b, 11a,b. After cleavage of the THP-ether and O-deacetylation 7-O-(2,6-dideoxy-2-iodo-α-L-manno-hexopyranosyl)-β-rhodomycinone (14) and 7-O-(2,6-dideoxy-2-iodo-α-L-talo-hexopyranosyl)-β-rhodomycinone (16) were obtained.