Soliton theory of squall storms

The theory of squall storms is developed. The results are compared with observations.     

3,6-Di-tert-Butyl-2-Hydroxy-4-Pyridinylphenolate and Tin(IV) Complexes it Forms: Synthesis and Structure Details and Solvatochromic Effect

Russian Journal of Coordination Chemistry - Two synthetic approaches were developed for the preparation of 3,6-di-tert-butyl-2-hydroxy-4-pyridinylphenolate (LH), a new zwitter-ionic redox-active...     

Hard disk magnetic domain nano-spatial resolution imaging by using a near-field scanning microwave microscope with an AFM probe tip

A near-field scanning microwave microscope (NSMM) incorporating an atomic force microscope (AFM) probe tip was used for the direct imaging of magnetic domains of a hard disk under an external magnetic field. We directly imaged the magnetic domain changes by measuring the change of reflection coefficient S₁₁ of the NSMM at an operating frequency near 4.4 GHz. Comparison was made to the magnetic force microscope (MFM) image. Using the AFM probe tip coupled to the tuning fork distance control system enabled nano-spatial resolution. The NSMM incorporating an AFM tip offers a reliable means for quantitative measurement of magnetic domains with nano-scale resolution and high sensitivity.     

Direct two-step synthesis of <Emphasis Type="Italic">n</Emphasis>-butyl acrylate–acrylic acid block copolymer by RAFT polymerization

A series of narrow-MMD polymers with the molecular mass from 33 × 10³ to 123 × 10³ (polydispersity coefficient 1.08–1.16) were synthesized by bulk polymerization of n-butyl acrylate [2,2′-azobis(isobutyronitrile), 60°C] in the presence of a low-molecular-mass RAFT agent, dibenzyl trithiocarbonate. Then, polymerization of acrylic acid was performed in aqueous-alcoholic solution (ammonium persulfate, 70°C) in the presence of the obtained polymers, and a series of n-butyl acrylate–acrylic acid block copolymers with the molecular masses from 22 × 10³ to 81 × 10³ (polydispersity coefficient 1.07–1.13) were prepared. In aqueous-alcoholic solutions of the synthesized copolymers, there are nanoparticles whose size varies from 5 tо 65 nm and increases with an increase in the molecular mass of the copolymer and in the concentration of water in the solvent.     

Storm surges as dissipative solitons

A nonlinear theory of storm surges was constructed. The results are compared with observation data.     

May chaos always be suppressed by parametric perturbations?

The problem of chaos suppression by parametric perturbations is considered. Despite the widespread opinion that chaotic behavior may be stabilized by perturbations of any system parameter, we construct a counterexample showing that this is not necessarily the case. In general, chaos suppression means that parametric perturbations should be applied within a set of parameters at which the system has a positive maximal Lyapunov exponent. Analyzing the known Duffing-Holmes model by a Melnikov method, we showed that chaotic dynamics cannot be suppressed by harmonic perturbations of a certain parameter, independently from the other parameter values. Thus, to stabilize the behavior of chaotic systems, the perturbation and parameters should be carefully chosen.     

Hyperelliptic jacobians with real multiplication

Let K be a field of characteristic p≠2, and let f(x) be a sextic polynomial irreducible over K with no repeated roots, whose Galois group is isomorphic to A₅. If the jacobian J(C) of the hyperelliptic curve C:y²=f(x) admits real multiplication over the ground field from an order of a real quadratic field D, then either its endomorphism algebra is isomorphic to D, or p>0 and J(C) is a supersingular abelian variety. The supersingular outcome cannot occur when p splits in D.     

Polymer‐assisted biocatalysis: Unprecedented enzymatic oxidation of fullerene in aqueous medium

Enzymatic complexes, constructed by linear‐dendritic copolymers and laccase, are used for the unprecedented one‐pot biotransformation of fullerene (C₆₀) into epoxide‐ and hydroxyl‐derivatives under mild and environmentally friendly reaction conditions (45 °C and aqueous medium). The reaction is catalyzed by mediator pairs ‐ N‐hydroxy‐5‐norbornene‐2,3‐dicarboxylic acid imide/1‐Hydroxybenzotriazole or 2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid)/1‐Hydroxybenzotriazole used in equimolar amounts. After 24 and 48 h, the biotransformation products ? C₆₀O_n, C₆₀(OH)_n, C₆₀(H)_n(OH)_n, and/or C₆₀O_n(H)_m(OH)_m range between 50 and 78%, respectively. Their structure is revealed by FTIR, NMR, and mass‐spectrometry. The mechanism of the process is discussed and elucidated. The reaction procedure allows the repeated usage of the enzyme/linear‐dendritic complex, which retains its catalytic activity after several cycles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012