No abstract

Phosphorus has been determined by electrothermal atomisation atomic absorption spectrometry with a molybdenum tube atomiser. The effects of interferents on the phosphorus signal have been investigated. Chemical interferences were eliminated by high-temperature pyrolysis. The detection limit for the molybdenum tube system was 2.3 ng (corresponding to 2.3 micrograms ml-1 when 1 microliter was injected into the atomiser) and the characteristic mass was 1.9 ng of phosphorus. A calibration graph method combined with high-temperature pyrolysis has been evaluated through the determination of phosphorus in biological materials. The sensitivity, accuracy and precision of the method were superior to or nearly equal to those of graphite furnace atomic absorption spectrometry. The advantages of the high-temperature pyrolysis method are its simplicity and low cost.

A method for the determination of sodium by sequential metal vapour elution analysis with hydrogen carrier gas combined with atomic absorption detection is described. The column is a molybdenum capillary tube (1.22 mm i.d.) and the temperatures are 1520-1 870 K. Sodium vapour was separated from Al, Ca, Cu, Mo and Zn vapours. The system was applied to the determination of sodium in National Institute of Standards and Technology Standard Reference Materials and the accuracy (reldive error) of the results obtained was within k 2%. Advantages of the system are direct separation of metals and the determination of sodium after wet digestion.

In concrete fiHed tubular columns ， the mechanism of stress transsmision betweerl the steel tube and concrete has not been clarified ， Therefore it is common to attach mechanlcal stoppers to the i 冂side of the tube ， Firstly ， we investigated the bearing strength of concrete and backing rings for tubular columns and approximated the ultimate strength ． Secondly ， we es セ imated the yield strength( 1Py) ， displacemen セ( 1δ｝and bearing spring ( K｝ on the surface of one ring whih was weldedinside the column ， Finally ， we could estimate the yield strength 〔 2Py ｝ and displacement ｛ 2δ ｝ by using ｛ 1Py)and ( K｝incase of two rings ．