The magnetic susceptibilities of platinum, rhodium and palladium from 20 to 290° K

An apparatus is described which makes possible the rapid determination of the temperature variation of the magnetic susceptibilities of small solid specimens. The deflexions of a beam of light passing through a Sucksmith balance are recorded photographically. The temperature of the specimen, measured by a Au-Co/Ag-Au thermocouple in contact with it, is initially reduced to 20° K and deflexions are recorded at small intervals of temperature as the temperature of the specimen rises to 290° K. The whole temperature range can be covered in 4 h. The mean deviation of single measurements from the best smooth curve passing through them is less than 0.2 % of the mass susceptibility of the specimens. The apparatus has been used to measure the temperature variation of the susceptibilities of spectrographically standardized specimens of platinum, rhodium and palladium. Measurements on three pure palladium specimens show a maximum in the susceptibility temperature curve at 80° K. The experimental results for platinum show a change in the curvature of the susceptibility temperature curve below 90° K, the susceptibility increasing more rapidly as the temperature decreases. The experimental results for rhodium show a regular increase of susceptibility with increase of temperature. The results for palladium are discussed in relation to the collective electron treatment of metals, and assuming a parabolic distribution of energy states in the d band, estimates are made of the effective Fermi-Dirac degeneracy temperature θ F , the number of holes per atom, q , and the exchange interaction energy θ' . The estimated values are θ F = 1020° K, q = 0.29, θ' = 554.0° K. Similar estimates are made in the case of platinum, the values being θ F =1750° K, q = 0.25, θ' = 770° K.

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Determination of Cyanide in Blood by Isotope-Dilution Gas Chromatography–Mass Spectrometry

Clinical Chemistry ◽

10.1373/clinchem.2005.061002 ◽

2006 ◽

Vol 52 (3) ◽

pp. 458-467 ◽

Cited By ~ 24

Author(s):

Karen E Murphy ◽

Michele M Schantz ◽

Therese A Butler ◽

Bruce A Benner ◽

Laura J Wood ◽

...

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Isotope Dilution ◽

Whole Blood ◽

Rapid Determination ◽

Internal Standard ◽

Gas Chromatography Mass Spectrometry ◽

Mean Deviation ◽

Chromatography Mass Spectrometry

Abstract Background: Cyanide (CN) is a lethal toxin. Quantification in blood is necessary to indicate exposure from many sources, including food, combustion byproducts, and terrorist activity. We describe an automated procedure based on isotope-dilution gas chromatography–mass spectrometry (ID GC/MS) for the accurate and rapid determination of CN in whole blood. Methods: A known amount of isotopically labeled potassium cyanide (K13C15N) was added to 0.5 g of whole blood in a headspace vial. Hydrogen cyanide was generated through the addition of phosphoric acid, and after a 5-min incubation, 0.5 mL of the headspace was injected into the GC/MS at an oven temperature of −15 °C. The peak areas from the sample, 1H12C14N+, at m/z 27, and the internal standard, 1H13C15N+, at m/z 29, were measured, and the CN concentration was quantified by ID. The analysis time was 15 min for a single injection. Results: We demonstrated method accuracy by measuring the CN content of unfrozen whole blood samples fortified with a known amount of CN. Intermediate precision was demonstrated by periodic analyses over a 14-month span. Relative expanded uncertainties based on a 95% level of confidence with a coverage factor of 2 at CN concentrations of 0.06, 0.6, and 1.5 μg/g were 8.3%, 5.4%, and 5.3%, respectively. The mean deviation from the known value for all concentrations was <4%. Conclusion: The automated ID GC/MS method can accurately and rapidly quantify nanogram per gram to microgram per gram concentrations of CN in blood.

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Weak Beam Imaging and Diffraction Studies of Stacking Faults in Silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092918 ◽

1976 ◽

Vol 34 ◽

pp. 590-591

Author(s):

T. Y. Tan ◽

W. K. Tice

Keyword(s):

Fast Neutron ◽

Rapid Determination ◽

Stacking Faults ◽

Imaging Method ◽

Large Reduction ◽

Dislocation Loops ◽

Fringe Spacing ◽

Weak Beam ◽

Kinematical Theory

In studying ion implanted semiconductors and fast neutron irradiated metals, the need for characterizing small dislocation loops having diameters of a few hundred angstrom units usually arises. The weak beam imaging method is a powerful technique for analyzing these loops. Because of the large reduction in stacking fault (SF) fringe spacing at large sg, this method allows for a rapid determination of whether the loop is faulted, and, hence, whether it is a perfect or a Frank partial loop. This method was first used by Bicknell to image small faulted loops in boron implanted silicon. He explained the fringe spacing by kinematical theory, i.e., ≃l/(Sg) in the fault fringe in depth oscillation. The fault image contrast formation mechanism is, however, really more complicated.

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