89 research outputs found
Submicron holes in thin films increase sampling range of mass spectrometers
Gold film is vapor deposited onto a glass slide containing submicron latex spheres which are removed, leaving submicron holes in the film. These thin-film apertures allow accurate mass spectrometer sampling of gas mixtures at pressures on the order of 100 torr
Metastable Solid Solutions in the Gallium Antimonide-Germanium Pseudobinary System
Abstract unavailable
Amorphous Phase in PalladiumâSilicon Alloys
By rapid cooling from the melt, an amorphous phase has been obtained in palladiumâsilicon alloys containing 15 to 23 at.% Si. This phase is stable at room temperature and crystallization cannot be detected after one month at 250°C. With rates of heating greater than 20°C/min, rapid crystallization takes place at 400°C, with a heat release of approximately 1000 cal/mole. The electrical resistivity of an alloy containing 17 at.% Si at room temperature is 2.6 times that of the equilibrium alloy. The resistivity decreases linearly with decreasing temperature and is about 95% of the room-temperature value at 2°K. Various factors involved in the retention of amorphous phases in rapidly quenched liquid alloys are discussed
Continuous series of metastable solid solutions in silver-copper alloys
A technique has been devised by which small amounts of liquid alloys can be cooled at rates high enough to prevent the normal process of nucleation and growth of equilibrium phases. The classical method for achieving high rates of cooling consists of injecting a small droplet of molten alloy into a liquid quenching bath. Olsen and Hultgren used such a technique in a study of the effect of the rate of cooling on the homogeneity of solid solutions.(1
Pulmonary Hypertension in Elderly Patients with Diastolic Dysfunction and Preserved Ejection Fraction
Abstract: Purpose: Patients with diastolic dysfunction may have a disproportionate degree of elevation in pulmonary pressure, particularly in the elderly. Higher pulmonary vascular resistance in the elderly patients with heart failure but preserved ejection fraction suggests that beyond the post-capillary contribution of pulmonary venous congestion, a pre-capillary component of pulmonary arterial hypertension occurs. We aim to identify if pulmonary vascular resistance in elderly patients with diastolic dysfunction is disproportionately higher than patients with systolic dysfunction independent of filling pressures. Methods: 389 patients identified retrospectively between 2003- 2010; elderly with preserved ejection fraction, elderly with depressed ejection fraction, and primary arterial hypertension who underwent right-heart catheterization at Rush University. Results: No significant difference in pulmonary vascular resistance between systolic and diastolic dysfunction. The mean difference in pulmonary vascular resistance was not statistically significant at 0.40 mmHg·min/l (95 % CI-3.03 to 3.83) with similar left ventricular filling pressures with mean difference of 3.38 mmHg (95 % CI,-1.27 to 8.02). When adjusted for filling pressures, there remained no difference in pulmonary vascular resistance for systolic and diastolic dysfunction. The mean pulmonary vascular resistance is more elevated in systolic heart failure compared to diastolic heart failure with means 3.13 mmHg·min/l and 3.52 mmHg·min/l, respectively
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