Composition tunable cobalt-nickel and cobalt-iron alloy nanoparticles below 10?nm synthesized using acetonated cobalt carbonyl

A general organometallic route has been developed to synthesize Co(x)Ni(1-x) and Co(x)Fe(1-x) alloy nanoparticles with a fully tunable composition and a size of 4-10?nm with high yield. In contrast to previously reported synthesis methods using dicobalt octacarbonyl (Co(2)(CO)(8)), here the cobalt-cobalt bond in the carbonyl complex is first broken with anhydrous acetone. The acetonated compound, in the presence of iron carbonyl or nickel acetylacetonate, is necessary to obtain small composition tunable alloys. This new route and insights will provide guidelines for the wet-chemical synthesis of yet unmade bimetallic alloy nanoparticles. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11051-012-0991-5) contains supplementary material, which is available to authorized users.     

Investigation of acceptance simulated annealing — A simplified approach to adaptive cooling schedules

Simulated annealing is the classic physical optimization algorithm, which has been applied to a large variety of problems for many years. Over time, several adaptive mechanisms for decreasing the temperature and thus controlling the acceptance of deteriorations have been developed, based on the measurement of the mean value and the variance of the energy. Here we propose a new simplified approach in which we consider the probability of accepting deteriorations as the main control parameter and derive the temperature by averaging over the last few deteriorations stored in a memory. We present results for the traveling salesman problem and demonstrate, how the amount of data retained influences both the cooling schedule and the quality of the results.     

On the semiaxes of touching quadrics

In this paper the semiaxes of quadrics which touch each other are investigated. If two quadrics Q, Q′ are given, it turns out that we can rotate Q′ such that it touches Q in two opposite points if and only if the squared semiaxes of Q, Q′ do not separate each other. This is equivalent to the statement that for two symmetric matrices A,B there is an orthogonal matrix S with det(A — S ^TBS) = 0 if and only if the eigenvalues of A and B do not separate each other.     

The cayley-dickson doubling process revisited

We introduce the category of composition triples over locally ringed spaces. In this category we find the category of composition algebras over locally ringed spaces as subcategory. We describe the Cay ley-Dickson doubling process in the category of composition triples.     

The double layer potential operator over polyhedral domains i: solvability in weighted sobolev spaces

We consider the integral equation, (λ-K)u=f, where K is the double layer (harmonic) potential operator on the boundary of a bounded polyhedron in R³ and λ∣λ∣≥1 is a complex constant. We study the mapping properties of λ - K in weighted Sobolev spaces, applying Mellin transformation techniques directly to the integral equation.