An overview of fast component-by-component constructions of lattice rules and lattice sequences

Since the initial work by I. H. Sloan and his collaborators on the component-by-component construction of good lattice rules for the approximation of multivariate integrals, a lot of variations on this theme have been published. These include various function spaces, prime and composite number of points, intermediate-rank rules, polynomial lattice rules and extensible rules. We sketch the different variations and discuss the properties needed to have a fast component-by-component construction. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Determination of the Stoichiometric Composition of High-Temperature Superconductors by ICP-OES for Production Control

 A procedure to dissolve and analyse different types of high-temperature superconducting materials in order to determine their stoichiometric com- position is described. As sample materials Y-Ba-Cu-O and (Pb)Bi-Sr-Ca-Cu-O were analysed. They were dissolved with hydrochloric acid and analysed by simultaneous ICP-OES, which fits best for this analytical task because of its multielement capacity, its high precision of determination and accuracy. Each of the relevant metals (Pb, Bi, Sr, Ca, Y, Ba, Cu) could be determined successfully. The precision of the determination was found to be better than 2% relative standard deviation and usually even below 1%. The sample preparation and determination procedure described allows a high sample throughput, which is essential for production control. Also precursors of the superconducting materials (e.g. nitrate solutions) could be analysed by the procedure described.     

Measuring unification

If supersymmetry is observed at the LHC its model parameters can be measured at the electroweak scale. We discuss the expected precision on the parameter determination, including a proper treatment of experimental and theoretical errors. Particular attention is paid to degenerate solutions. Using the SFitter framework we perform a bottom–up reconstruction of the unified parameters at the high scale, including a full error propagation.     

Physical aging and deformation kinetics of polycarbonate

Considering the current view that physical aging of glasses results in an increase of activation barriers to plastic deformation, it is surprising that, until now, no influence of physical aging was observed experimentally on the temperature dependence of plastic deformation in polymeric glasses. This study evaluates why such an influence has not been found, and it is shown that detailed analysis of a set of uniaxial compression data on polycarbonate (PC) at different strain rates and temperatures leads to the conclusion that a significant influence indeed exists. As a consequence, the Eyring activation energy depends on the aging history of the material. These experimental observations are rationalized in terms of a simple physical interpretation of the aging phenomenon. The article also contains a discussion of the apparent deaging of amorphous polymers induced by large‐strain plastic deformation. This discussion is of key importance here, because this study compares yield stresses of aged PC with those of mechanically deaged, or rejuvenated, PC. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Influence of the processing solvent on the photoactive layer nanomorphology of P3HT/PC60BM solar cells

In this article, it is demonstrated that doctor blading of thin poly‐3‐hexylthiophene/phenyl‐C₆₁‐butyric acid methyl ester (1/1) bulk‐hetero junction films from toluene leads to an improved nanocrystallinity, when compared with their unannealed chlorobenzene processed counterparts. This difference in morphology was demonstrated by solid‐state NMR and Rapid Heating Cooling Calorimetry (RHC), being useful complementary techniques to investigate the active layer morphology of photovoltaic devices. An increased PC₆₀BM nanocrystallinity is indicated by several NMR relaxation decay times (T_1C, T_1H, and T_1ρH) and confirmed by an increase of the melting enthalpy in RHC experiments. An improved solar cell performance further strengthens this conclusion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012