Flux-Closure Magnetic States in Triangular Cobalt Ring Elements

Ferromagnetic ring elements on the micrometer and submicrometer scale exhibit flux-closure magnetic vortex states in an intermediate step of their magnetization reversal. These clockwise or counterclockwise flux-closure states are of interest for applications that encode binary information in magnetic elements. Here, we study the magnetization reversal process of triangular cobalt rings made by e-beam lithography and lift-off. We demonstrate that full control over the direction of flux-closure magnetic states can be achieved solely by homogeneous external magnetic fields applied in particular directions. We have extracted statistical experimental data pertaining to the range of critical field values that trigger magnetization reversal from magnetic force microscopy images, and we explain the results on the basis of micromagnetic simulations     

Dehydrogenation of methanol to methyl formate: deuterium labeling studies

Different synthetic AlPO₄ systems are effective yet mild acid catalysts for the heterogeneous cycloaddition reaction of cyclopentadiene with (-)-menthyl acrylate. The reaction proceeds selectively under mild conditions and in a relatively short reaction time with an almost total conversion, a high endo/exo ratio, and a reasonable asymmetric induction. When the reactions are carried out without solvent, some correlations are obtained between the number of acid sites, titrated with pyridine, and reaction yields, endo/exo and diastereofacial selectivities. The positive influence of surface area of catalysts is also determined. However, the lack of good correlations between reaction results and surface properties of the catalysts indicates the influence of some other factors.     

Co‐immobilized Whole Cells with ω‐Transaminase and Ketoreductase Activities for Continuous‐Flow Cascade Reactions

An improved sol–gel process involving the use of hollow silica microspheres as a supporting additive was applied for the co‐immobilization of whole cells of Escherichia coli with Chromobacterium violaceum ω‐transaminase activity and Lodderomyces elongisporus with ketoreductase activity. The co‐immobilized cells with two different biocatalytic activities could perform a cascade of reactions to convert racemic 4‐phenylbutan‐2‐amine or heptan‐2‐amine into a nearly equimolar mixture of the corresponding enantiomerically pure R amine and S alcohol even in continuous‐flow mode. The novel co‐immobilized whole‐cell system proved to be an easy‐to‐store and durable biocatalyst.     

Key role of the desolvation in the achievement of the quasi-metallic state of electronically conducting polymers

Redox transformation of electronically conducting polymers was studied by different in situ combined electrochemical techniques. Results obtained with polypyrrole/dodecyl sulfate film in aqueous solution and with polythiophene/hexafluorophosphate films in acetonitrile by in situ ac conductance and EQCM support the assumption of the key role of the desolvation in the achievement of the so-called quasi-metallic state of electronically conducting polymers. The desolvation considered as a phase transition is the chemical background of the capacitive behaviour, and it causes the structural changes, which lead to a film in which the interchain interactions may form the large-scale conducting polymer matrix.     

The density matrix renormalization group algorithm on kilo-processor architectures: Implementation and trade-offs

In the numerical analysis of strongly correlated quantum lattice models one of the leading algorithms developed to balance the size of the effective Hilbert space and the accuracy of the simulation is the density matrix renormalization group (DMRG) algorithm, in which the run-time is dominated by the iterative diagonalization of the Hamilton operator. As the most time-dominant step of the diagonalization can be expressed as a list of dense matrix operations, the DMRG is an appealing candidate to fully utilize the computing power residing in novel kilo-processor architectures.     

A simple three-parameter equation of state with critical compressibility-factor correlation

A three-parameter equation of state is proposed for fluids whose critical compressibility factor is not greater than 0.275. The equation is third order in volume and its constants are evaluated from the critical temperature and pressure as well as from the premultipliers that are interrelated and dependent on the reduced limiting volume of the fluid. The premultipliers have been evaluated from a single compressibility-factor correlation extrinsically. The proposed equation is as easy to handle mathematically as the Redlich-Kwong equation and yields analytical expressions for various fluid properties. The results show, however, that it represents the properties of normal and polar fluids much more accurately, particularly in the saturated vapor and the liquid region.     

Detection of soldering defects in Printed Circuit Boards with Hierarchical Marked Point Processes

In this paper we introduce a probabilistic approach for optical quality checking of solder pastes (SP) in Printed Circuit Boards (PCB). Dealing with unregistered image inputs, our task is to address at the same time SP identification, and detection of special soldering errors, called scooping. For this reason we introduce a novel Hierarchical Marked Point Process (HMPP) framework, which is able to handle the paste and scooping extraction problems simultaneously, so that the SPs and included scoops have a parent-child relationship. A global optimization process attempts to find the optimal configuration of entities, considering the observed data, prior knowledge, and interactions between the neighboring circuit elements. The proposed method is evaluated on a real PCB image set containing more than 3000 SPs and 600 scooping artifacts. A morphology-based baseline method is also introduced for the problem and used as reference for qualitative and quantitative comparison against the proposed model.     

Fetal phonocardiography--past and future possibilities

The paper presents an overview of the 15 year long development of fetal phonocardiography including the works on the applied signal processing methods for identification of sound components. Based on the improvements achieved on this field, the paper shows that beyond the traditional CTG test the phonocardiography may be successfully applied for long-term fetal measurements and home monitoring. In addition, by indication of heart murmurs based on a comprehensive analysis of the recorded heart sound congenital heart defects can also be detected together with additional features in the third trimester. This makes an early widespread screening possible combined with the prescribed CTG test even at home using a telemedicine system.     

Alignment based kernel learning with a continuous set of base kernels

The success of kernel-based learning methods depends on the choice of kernel. Recently, kernel learning methods have been proposed that use data to select the most appropriate kernel, usually by combining a set of base kernels. We introduce a new algorithm for kernel learning that combines a continuous set of base kernels, without the common step of discretizing the space of base kernels. We demonstrate that our new method achieves state-of-the-art performance across a variety of real-world datasets. Furthermore, we explicitly demonstrate the importance of combining the right dictionary of kernels, which is problematic for methods that combine a finite set of base kernels chosen a priori. Our method is not the first approach to work with continuously parameterized kernels. We adopt a two-stage kernel learning approach. We also show that our method requires substantially less computation than previous such approaches, and so is more amenable to multi-dimensional parameterizations of base kernels, which we demonstrate.