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Gibbs formulated a complete and general thermodynamics for surfaces in multicomponent fluid systems. When considering solid-fluid surfaces, he restricted attention to single-component solids in contact with fluids that could contain multiple components. Attempts that have been offered to generalize Gibbs' results for surfaces between multicomponent solids and fluid are problematic owing to the difficulty that the surface chemical potentials for components that also reside on substitutional lattice sites in the solids are not well defined. Therefore any expressions involving these surface chemical potentials, such as the conventional definition of the surface energy, will also not be well defined. In order to formulate a general thermodynamics of equilibrium that takes into account capillary effects in systems containing surfaces between a multicomponent solids and fluids, it is shown that the concept of thermodynamic availability (exergy) can be employed that, when applied to surfaces, depends on the extensive but not the intensive variables (such as the chemical potentials) of the surfaces. Using this approach, Gibbs-Thomson-Freundlich effects for finite-size solids, an adsorption equation for solid-fluid surfaces and the thermodynamics of nucleation during solidification can be treated in a straightforward manner without referring to the ill-defined surface chemical potentials. A derivation is given that appears to be the first one that properly generalizes Gibbs' analysis for the reversible work to form a critical nucleus to the case of solidification. [ABSTRACT FROM AUTHOR]

High aspect ratio Fe0.55Co0.45 alloy nanowires were fabricated by electrochemical deposition from sulfamate solution into nanoporous templates with diameters between 20 and 200 nm and lengths up to 6 µm. The capability to fill narrow (down to 20 nm in diameter) and deep (micrometer size) pores with high magnetic flux density Fe-Co alloys makes it a potential candidate for deposition of the writer poles in hard disk drives. The deposited nanowires were polycrystalline with a grain size of about 10-40 nm. Strong magnetic shape anisotropy is characteristic of the deposited high aspect ratio Fe-Co nanowires. The saturation magnetization of the nanowires was about 22-24 kG, in excellent agreement with values reported for bulk Fe-Co alloys. For nanowires with diameters in the range from 30 to 100 nm, magnetic reversal is shown to be consistent with the curling model. [ABSTRACT FROM AUTHOR]

We report on the formation of nickel silicide in nickel-implanted amorphous silicon thin films. We have found that during annealing, precipitates of NiSi2 form in the interior of the film. This is in contrast with results for interfacial reactions between nickel films and silicon, where the first phases to appear are Ni2Si and NiSi on amorphous silicon, and Ni2Si on crystalline silicon. We suggest that these results reflect differences in surface energies and their effects on silicide nucleation. [ABSTRACT FROM AUTHOR]

We report on the use of differential scanning calorimetry to study the temperatures and kinetics of nickel silicide formation from nickel/amorphous silicon multilayer films. When the layer thickness ratio of a multilayer film is 1:1, Ni2 Si is the only phase to form. The activation energy for this reaction is 1.5 eV and the interdiffusivity pre-exponential is found to be 6 cm-2s-1. These values are in excellent agreement with values obtained using different techniques. The temperature at which Ni2 Si formation is observed a function of layer thickness, with the thinner layers reacting at lower temperatures. This layer thickness dependence can be explained by the lower reaction times for thinner layers. Upon mechanical impact, films composed of very thin layers (<125 Å) reacted explosively at room temperature to form Ni2 Si. Explosive silicidation is presumed to occur when the rate of heat generation at the many reacting interfaces exceeds the rate of heat dissipation. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor concerning negative surface energy.

Angiotensin II receptor blockers represent a class of effective and well tolerated orally active antihyperten-sive drugs. Activation of AT[SUB1] receptors leads to vasoconstriction, stimulation of the release of cat-echolamines and antidiuretic hormone and promote growth of vascular and cardiac muscle. AT[SUB1] receptor blockers antagonise all those effects. Losartan was the first drug of this class marketed, shortly followed by val-sartan, irbesartan, telmisartan, candesartan, eprosartan and others on current investigation. All these drugs have the common properties of blockading the AT[SUB1] receptor thereby relaxing vascular smooth muscle, increase salt excretion, decrease cellular hypertrophy and induce antihypertensive effect without modifying heart rate or cardiac output. Most of the AT[SUB1] receptor blockers in use controlled blood pressure during the 24 h with a once-daily dose, without evidence of producing tolerance to the antihypertensive effect and being with low incidence of side effects even at long term use. Monotherapy in mild-to-moderate hypertension controls blood pressure in 40 to 50% of these patients; when a low dose of thiazide diuretic is added, 60-70% of patients are controlled. The efficacy is similar to angio-tensin-converting enzyme (ACE) inhibitors, diuretics, calcium antagonists and beta-blocking agents. AT[SUB1] receptor blockers are specially indicated in patients with hypertension who are being treated with ACE inhibitors and developed side effects such as, cough or angio-edema. The final position in the antihypertensive therapy in this special population and other clinical situations, such as left ventricular hypertrophy, heart failure, diabetes mellitus and renal disease, has to be determined in large prospective clinical trials, some of which are now being conducted and seem promising. [ABSTRACT FROM AUTHOR]