Безаберрационная ширина углового спектра зондирующего слоистый объект поля в конфокальной микроскопии

The effect of the numerical aperture of a light beam probing an object on the value measured by a confocal interference microscope when determining the thickness of a layered object for the case of a significant effect on the signal of the spherical aberration arising in the probe beam at its propagation through an object has been theoretically and experimentally investigated. Taking into account the influence of spherical aberration on the signal the dependence of the measured value on the numerical aperture has been obtained. The criterion of the “aberration-free” propagation of the beam probing an object has been established and the condition under which the effect of spherical aberration on the signal of a confocal microscope can be neglected has been determined. An approximate analytical expression which allows to determine the “aberration-free” width of angular spectrum of the probing light beam taking into account the empirical correction factor has been obtained. The limits of applicability of the analytical dependence of the measured value on the numerical aperture, which was obtained earlier for the case of negligible influence of spherical aberration on the signal of a confocal microscope, have been determined.

Sample thickness and quantitative concentration measurements in BrK-edge XANES spectroscopy of organic materials

While XANES spectroscopy is an established tool for quantitative information on chemical structure and speciation, elemental concentrations are generally quantified by other methods. The edge step in XANES spectra represents the absolute amount of the measured element in the sample, but matrix effects and sample thickness complicate the extraction of accurate concentrations from XANES measurements, particularly at hard X-ray energies where the X-ray beam penetrates deeply into the sample. The present study demonstrates a method of quantifying concentration with a detection limit approaching 1 mg kg−1using information routinely collected in the course of a hard X-ray XANES experiment. The XANES normalization procedure unambiguously separates the signal of the absorber from any source of background. The effects of sample thickness on edge steps at the bromineK-edge were assessed and an empirical correction factor for use with samples of variable mass developed.

RE-EVALUATION OF THE CORRECTION FACTOR FOR ETHANOL IN THE CALCULATION OF THE OSMOLAL GAP

Background/objectives: It is well-known that ethanol (EtOH) demonstrates non-ideal solute behaviour in plasma. This is reflected by its larger than expected contribution to the plasma osmolality. Published multiplicative correction factors for the EtOH contribution range from 1.20 to 1.25. The objective of this study is to determine an optimal correction factor specific to the instrumentation at Vancouver General (VGH) and St. Paul's (SPH) Hospitals. Methods: Laboratory data from patients presenting to the two respective emergency department between August 01, 2007 and November 30, 2008 were extracted from the Sunset database. Plasma sodium, urea, glucose, and EtOH were measured using the two high-volume chemistry analyzers employed at the sites: the Siemens (previously Dade) RXL (VGH) and the Siemens (previously Bayer) Advia 1650 (SPH). Plasma osmolality was measured by freezing-point depression and calculated (excluding the EtOH contribution) using the following standard formula (in SI units): 2 [Na] + [Urea] + [Glucose]. Patients without EtOH data or who had undetectable EtOH were excluded as were patients with methanol or ethylene glycol present. Standard regression statistics were employed. Results: Twelve hundred and fifty-three patient samples (n=823 from SPH and n=430 from VGH) were included. Empirical correction factor m, satisfying, Osmol gap (mmol/kg) =m[EtOH] (mmol/L) was consistently found to be 1.15 for VGH, SPH and both combined. Conclusions: The correction factor of 1.15 for ethanol from the current study appears to be more representative and reliable. Further studies to evaluate its validity in other hospital sites as well as its utility in screening patients with known toxic alcohol ingestion will be warranted.

Comparison of Soil Properties From World-Wide Full-Scale Pipe Testing Facilities

The dynamic behavior of an axially propagating crack in buried line pipe is dependent not only on the pipe material, and the decompressing gas, but also the surrounding soil. The density and cohesiveness of the soil restrains the forming pipe flaps behind the crack tip and decreases the apparent crack driving force. Traditional fracture analyses, such as the Battelle Two-Curve (BTC) approach, lump the soil behavior into one empirical correction factor that does not differentiate between different soil types. In this effort, soils from the full-scale pipe test facilities in the United States, Italy, United Kingdom, and Denmark, were tested with standard procedures to characterize the soils by type, grain size, density and strength. A comparison of these properties is presented in this archival paper, which can be used in future fracture analysis development efforts.

Subsidence Associated With Single and Multicavities for Underground Coal Gasification

The three-dimensional theoretical development of Berry and Sales [1] has been extended to bring the subsidence predictions into agreement with the British National Coal Board comprehensive set of empirical data. New elastic parameters have been determined to fit the amplitude of the ground level subsidence. An empirical correction factor was developed to account for small cavity width-to-depth ratio cases. This correction is believed to account for incomplete closure for half width-to-depth ratios below 0.3. The theory has also been modified to bring the subsidence profiles into agreement with the foregoing referenced data. The development has been used to predict subsidence for an actual U.S. coal mining case with multiple cavities. The theory was also used to predict subsidence level and profile for a recent Gulf/DOE UCG test conducted in a steeply dipping coal seam near Rawlins, Wyoming.

Experimentelle Untersuchungen zur Stark-Verbreiterung der Balmer-Linien Hα und Hβ / Experimental Investigation of the Stark Broadening of the Balmer Lines Hα and Hβ

The profiles of the Stark broadened Balmer lines Hα and Hβ have been measured in a wide range of temperature and electron density. By the use of different light sources (3 wallstabilized arcs of different design, a pulsed discharge tube and a plexiglass-capillary discharge) the range was ex- tended to 1.0·104≦T≦3.2·104 °K for the plasma temperature and to 1·1016≦ne≦55·1016 cm−3 for the electron density in the Hβ-scale. The experimental profiles of the Hα-line agree with generalized impact approximations if the condition: ne2/3/T>2·107 cm−2 grad−1 is fulfilled. Disagreements between the Hα and Hβ electron density scale can be removed applying an empirical correction-factor to the electron density obtained from the half-width of Hα.