[en] This examination paper includes a statistical analysis of radon measurements from dwellings. By using variance analysis it has been investigated in what way the measured radon level depends on factors like smoking, time of measurement, different detecting points in the house, and the dependence of geographical localization. Apart from the classification in risk levels, the time of measurement was very important. The statistical analysis have been made with the aid of the computer program package SAS. Proposals are given for the planning of future measurements. (author)

[en] Theoretical and experimental work on the nature of the 5f electrons in the actinide series is reviewed briefly. It is suggested that intra-atomic coulomb repulsion between 5f electrons is of great importance in the actinides and quantitative support is given to the itinerant picture of the 5f states already found in band structure calculations. The effective intra-atomic interaction is calculated by the same method as applied to cerium in earlier work. The question of valencies in the actinides is discussed; the appearance of superconductivity is correlated with the f-bandwidth. 19 references

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[en] A mathematical approach is used to study the existence of divalent f-configuration metals by a condensation process involving the cohesive energy and the excitation energy of the atoms. Among the lanthanides only europium and ytterbium are expected to be +2-metals. Americium is expected to be a +3-metal; nobelium, mendelevium, fermium, and einsteinium are expected to be divalent; and californium is expected to be on the borderline between +2 and +3. The method is also applied to compounds and to +4 metals such as zirconium, hafnium, thorium, neptunium, and uranium. 2 figures

[en] An interpolation procedure is introduced for obtaining the heat of formation of various halide and oxide compounds. From this scheme it becomes possible to derive the energy difference between trivalent and tetravalent rare-earth and actinide metals (with non-bonding f-electrons). As an example, for cerium it is found that this energy separation is about 40 kcal/mol, a finding which definitely rules out the promotion model for this metal. For the early actinide metals the metallic bonding contribution due to the itinerant 5f electrons also becomes evident. From the energy differences between different valence states of the f-metals, a rather extensive stability study of various halide and oxide systems can be undertaken. The success of this investigation reinforces the reliability of the derived energy differences between the metallic valence states. (author)

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[en] A first-principles investigation of the core-level binding energy shifts (CLS) for the 3d_5/2 core-electrons of Ag, Pd and 2p_3/2 of Cu was carried out for the f.c.c. Ag-Pd and Cu-Pd random alloys within the model of complete screening, which includes both the initial and final state effects, and compared to initial state calculations. It is shown that the model of complete screening in general gives good agreement with experiment and is in substantially better agreement with experiment in the case of Pd when compared to the initial state calculations

[en] Linear-muffin-tin orbital calculations of the band structure and pressure-volume isotherms for fcc La, both at zero and finite temperatures. The calculated bulk modulus shows a rapid stiffening in the range from 40 to 50% compression, due to termination of the 6s to 5d electronic transition. When combined with a simple Slater model analysis, these results yield a temperature dependent peak in the lattice Grueneisen parameter. Experimental confirmation of this peak is found in an anomalous stiffening seen in the shock compression data for La, and it may also have some bearing on the observed saturation of the superconducting transition temperature in La around 200 kbar