Vol. 18, No. 10 (1962)
1962-05-20
CONTENT
1962, 18 (10): 491-500.
doi: 10.7498/aps.18.491
Abstract +
The energy bands of the zinc blende structure are treated by the simplified LCAO method of Slater and Koster. A model of the chemical bond is proposed for the purpose that the matrix elements involved may be expressed in terms of certain parameters of the chemical bonds. The energy levels of a number of points in the Brillouin zone are investigated. With this approach, we discuss the variation of the band gap as well as the position shift of the conduction band edge with the change of chemical compositions.
1962, 18 (10): 501-508.
doi: 10.7498/aps.18.501
Abstract +
The assumption of the relaxation of the reaction MgSO4←→Mg+++SO4-- to be the basis of sound absorption in water has not sufficient ground. In this paper, the author derives a formula for relaxation absorption based on the chemical thermodynamics, and the supposition from which the phenomenological theory started is also explained. With the consideration of Debye-Hückel ionic atmosphere theory, the formula obtained is applied to the water solution of MgSO4. A critical discussion is given to the existing theories.
1962, 18 (10): 509-513.
doi: 10.7498/aps.18.509
Abstract +
The Green's function of a single π-meson is obtained by the method of dispersion telation utilizing the analytic and unitary properties of the nucleon-antinucleon scattering amplitude. No renormalization procedure is needed.
1962, 18 (10): 514-526.
doi: 10.7498/aps.18.514
Abstract +
A periodic field formed with three or five lens elements can be used as an image-forming lens in ion-optics. Generally, it possesses much stronger focusing ability than a single lens element under the same voltage ratio. Periodic field lenses have been used as initial focusing systems of ion sources in some electrostatic accelerators, yet its image-forming characteristics have not been fully studied.This paper proposes a method to investigate the image-forming characteristics of periodic field lenses. Treating periodic field lens as a lens-element-combination, the expressions of its cardinal points can be obtained by using Ferrarias characteristic determinant. For a general case, with immersion lens as lens element, the expressions of cardinal points of periodic field lenses of three and five lens elements have been given. In these expressions only cardinal parameters of lens element and geometrical parameters of electrode system are involved. These derived expressions are quite simple in form, easy for calculation with sufficient accuracy. Thus there is no difficulty in studying the general characteristics of these lenses.Using these expressions, the image-forming characteristics of some periodic field lenses with symmetrical two-tube lens of small gap-spacing as lens element have been calculated and analysed.
1962, 18 (10): 527-539.
doi: 10.7498/aps.18.527
Abstract +
In this paper the characteristics of cavity chambers of different wall material (graphite, bakelite, Al) and different volume are studied. Using this method, the dose rate of γ-rays of Ra is obtained. The experimental result is (corrected for density effect of wall material) 8.74±0.27 γ/mg/hr, at 1 cm off the source (without Pt packing). Using the correction factor of the different thicknesses of Pt packing of Laurence, this value becomes 8.15±0.27 γ/mg/hr (Source in 0.5 mm Pt).This result is in good agreement with previous works within the experimental errors.
