Electrochemical Detection in HPLC Part 2. Applications

The range of applications of electrochemical HPLC detectors is outlined and the most important groups of applications are described. Typical examples of determinations are given in tables.     

Coding techniques for the noisy magnetic recording channel: astate-of-the-art report

Coding techniques for improving the reliability of information storage on noisy magnetic recording channels are considered. It is assumed that the Lorentzian channel model applies and that the retrieved signal is perturbed with additive white Gaussian noise. The immunity against additive noise of state-of-the-art codes such as DC-free, runlength-limited, and trellis codes are assessed     

Electron diffraction study of enzyme-hydrolyzed cotton samples

An electron diffraction study on continuously and repeatedly enzyme-hydrolyzed cotton samples was carried out. The electron diffraction pattern on repeatedly enzyme-treated sample reveals a cellulose I pattern with the absence of the 101 plane. This confirms that enzymatic hydrolysis of cotton fibers proceeds preferentially along the 101 plane, being a clevage plane.     

A compact fiber-optic magnetometer employing an amorphous metalwire transducer

A compact fiber-optic magnetometer constructed using a short piece of amorphous metal wire (5-cm long×100-μm diameter) as the magnetostrictive transducer is discussed. The inherently large ratio of length to cross-sectional area results in a low demagnetization along the axial direction. A magnetostrictive constant of 5×10^-5 /Oe², which is 10-50 times larger than the reported values for transducers made from Metglas ribbons, was measured. Minimum detectable magnetic fields on the order of 10^-5 Oe/Hz^1/2 at 1 Hz were achieved using a 5-cm-long sensing fiber     

Finite element formulation by parametrized hybrid variational principles: Variable stiffness and removal of locking

In this paper, a new one-parameter hybrid functional is obtained as a special case of Felippa and Militello's parametrized variational principles. The functional contains stress, strain and compatible displacement as the primary fields. It will be proved that some of the existing variable stiffness formulations fall into the framework of the new functional. Novel applications of the functional are also suggested, mainly for removal of locking. Solid element, destabilized 8-node and stabilized 9-plate elements are designed. All of them can handle thin plate/shell analysis. In particular, a prominent method is devised for constructing stabilization vectors. The vectors are explicit linear functions of the nodal coordinates and can be implemented without resorting to Gram–Schmidt orthogonalization or numerical integration. Results of the new elements in popular benchmark tests are encouraging.     

Characterization of Al-doped n-type ZnSe prepared under a zinc-rich growth condition by low-pressure organometallic chemical vapor deposition

High conductivity n-type ZnSe with = 0.01 ωcm and n = 2.4 × 10¹⁸ cm⁻³ is obtained on (100) GaAs substrates by low pressure organometallic chemical vapor deposition. The 14 meV full width at half maximum of the 77 K photoluminescence near-band-edge emission shows a high quality of as-grown Al-doped ZnSe epilayers. With a suitable Al doping level, a strong photoluminescence intensity of near-band-edge emission is obtained. The behavior of near-band-edge emission and of self-activated emission related to the incorporation of aluminum are discussed in this paper.     

Fracture behaviour of unmodified and rubber-modified epoxies under hydrostatic pressure

The fracture toughness and uniaxial tensile yield strengths of unmodified and CTBN-rubber-modified epoxies were measured under hydrostatic pressure. The purpose of these experiments was to learn how suppressing cavitation in rubber particles affects the deformation mechanisms and the fracture toughness of rubber-modified epoxy. It was found that the cavitation of CTBN-rubber could be suppressed at a relatively low pressure (between 30 and 38 M Pa). With cavitation suppressed, the rubber particles are unable to induce massive shearyielding in the epoxy matrix, and the fracture toughness of the rubber-modified epoxy is no higher than that of the unmodified epoxy in the pressure range studied. Unmodified epoxy shows a brittle-to-ductile transition in fracture toughness test. The reason for this transition is the postponement of the cracking process by applied pressure.Work performed while on a sabbatical leave at the University of Michigan.     

Expert performance: Its structure and acquisition.

Counter to the common belief that expert performance reflects innate abilities and capacities, recent research in different domains of expertise has shown that expert performance is predominantly mediated by acquired complex skills and physiological adaptations. For elite performers, supervised practice starts at very young ages and is maintained at high daily levels for more than a decade. The effects of extended deliberate practice are more far-reaching than is commonly believed. Performers can acquire skills that circumvent basic limits on working memory capacity and sequential processing. Deliberate practice can also lead to anatomical changes resulting from adaptations to intense physical activity. The study of expert performance has important implications for our understanding of the structure and limits of human adaptation and optimal learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)