Vol. 22, No. 7 (1966)
1966-04-05
CONTENT
1966, 22 (7): 733-742.
doi: 10.7498/aps.22.733
Abstract +
The enhancements of sodium atomic-absorption and emission by methyl-, ethyl-, and propyl-alcohol of various concentrations were studied under identical conditions with a modified Zeiss Model Ⅲ flame photometer. The spray rate, the effective spray rate (i.e., the amount of spray reaching the flame per unit time), the flame temperature, and the surface tension and viscosity for various alcohol-water solutions were measured, and a possible mechanism of the enhancements was suggested. According to this mechanism, it was shown that although the enhancement in absorption results mainly from an increase in the effective spray rate, but for alkali metals, which have low ionization potentials, the reduction of the degree of ionization due to the lowering of the flame temperature also plays a definite role. As for the enhancement in emission, it was shown that in addition to the changes in effective spray rate and degree of ionization, the change in the Boltzmann factor exp(-Ei/kT) should also be taken into account.
1966, 22 (7): 743-748.
doi: 10.7498/aps.22.743
Abstract +
At about 850℃ on common glass welded cuprous oxide crystal sample is under more than 10kg/mm2 plane compressive stress at 77°K. We have investigated systematically the splittings and intensities of the strong reflection lines of the pale-blue and blue exciton line series in some samples with plane stress perpendicular to C4, C3, and C2 symmetry axes of the crystal respectively. If it is assumed, as by E. F. Gross and colleagues, that these series are relative to Γ7+-Γ8- and Γ8+-Γ8- band edge transitions, the present experimental facts can be interpreted satisfactorilly. The effects of the same stress on the yellow and green hydrogenic exciton line series of this crystal are investigated also. For the cases of plane stress perpendicular to C4, C3, and C2 symmetry axes respectively, the shift of each line of these series are determined, the results show that the effect of the stress on the Rydberg constant and the series limit of the green series is large than that of the yellow series.
1966, 22 (7): 749-756.
doi: 10.7498/aps.22.749
Abstract +
By the method of the oscillating sphere, as developed by Andrade and Chiong, we have determined the viscosities of three samples (K: 49%, 51%, 74%) of the liquid alloy NaK, the temperature range being about 300℃. The result showed that the liquid alloys in the temperature range measured follow the Andrade's law η =Beb/T quite satisfactorily. In the paper, in addition to descriptions of apparatus design and new improvements made, some salient points of interest are discussed.
1966, 22 (7): 757-764.
doi: 10.7498/aps.22.757
Abstract +
The densities of liquid sodium, potasium, and their alloy NaK have been measured, in the temperature range 0-300℃, by the dilatometer method, special attention being paid to temperature control and to the purification of the metals. It is found that the density of the liquid metals Na and K can all be adequately expressed as a linear relation with the temperature, though our values are slightly higher than those given by Hagcn. In the case of the liquid alloy, the three samples (K: 49%, 51%, 74%) give also almost parallel straight lines, but with the exception that as the temperature approaches the melting point of the alloy, the density shows quite systematical deviations, probably indicating some strutural change in the alloy even long before freezing.
1966, 22 (7): 765-769.
doi: 10.7498/aps.22.765
Abstract +
The energy gap of a superconducting film with current flowing is calculated, based on the theory reported in the previous Paper [1]. The result is valid in the whole temperature range but only for small currents. The critical current of a superconducting film is also discussed for temperatures near Tc. It is pointed out that the non-local effect is important for thick films, but not for thin films.
1966, 22 (7): 770-780.
doi: 10.7498/aps.22.770
Abstract +
In this paper, we have calculated the energy gap of a superconducting film in a magnetic field. The result is valid in the whole temperature range but only for small magnetic field satisfying the condition ((e?p0/(mc) A/(πkBTc))2《1, where A is the vector potentialand ?p0 is Fermi momentum. The results are compared with the experimental data, and agreement is good.
1966, 22 (7): 798-808.
doi: 10.7498/aps.22.798
Abstract +
In this paper a general formula was derived for semiconductor resistivity measurements, in which four probes may be set in any positions. From this formula, we have obtained a general expression for calculating the probe-wander error; and the transverse probe-wander as well as the longitudinal probe-wander error have been considered simultaneously. So, we can evaluate the probe-wander errores of linear probes and square probes. In addition, we have derived the probe-wander error in sheet specimens measurements with these two kinds of probes. Theory has indicated that the probe-wander error cannot be ignored in an accurate measurement. Lastly, we have discussed the methods of eliminating or decreasing the probe-wander error.
1966, 22 (7): 809-826.
doi: 10.7498/aps.22.809
Abstract +
This paper proposes some new ideas on the theory of coupled waveguides which was formerly discussed in literature [1]. A new suggestion on inter-boundary condition, and a new method of treatment have been offered. Two forms of coupled slots, shallow and deep, are considered. The electric field in the mouth of slot is estimated by approximate methods, then the electromagnetic field both in coupled rectangular and circular waveguides with their tensor Green functions is derived. It has been pointed out in this paper that the results of application of boundary condition, the characteristic equation, can be accounted for as the equality of admittance of two LC circuits. There are some discussions on the relations between propagation constants of coupled waveguides and those of individual waveguides. As concluding remarks, some simple applications of the theory are mentioned.
