Vol. 23, No. 5 (1974)
1974, 139 (5): 5-16. doi: 10.7498/aps.23.5
In this paper, using E. Carten's exterior calculus, we give the spinor form of the structure equations, which leads naturally to the Newman-Penrose equations. Further, starting from the spinor space and the sl(2C) algebra, we construct the general complex-vector formalism of general relativity. We find that both the Cahen-Debever-Defrise complex-vector formalism and the Brans one are its special cases. Thus, the spinor formalism and the complex-vector formalism of general relativity are unified on the basis of the unimodular group SL(2C) and its Lie algebra.
1974, 139 (5): 17-22. doi: 10.7498/aps.23.17
The internal information, i.e. the syllable formation rule, of the language plays an important role in the statistical relation between the syllable articulation and the phoneme articulation, especially when the articulation scores are low. This is taken account in deriving an expression for the relation between the syllable articulation and the phoneme articulation scores, which agrees well with the experimental results of standard colloquial Chinese and accounts for the differences between theory and experiment for English and Japanese by previous authors.
1974, 139 (5): 23-42. doi: 10.7498/aps.23.23
In some switching circuits employing tunnel diodes, it is found that a stationary relaxation oscillation may be obtained by triggering methods. Triggered quasi-sinusoidal oscillations have been discussed by some authors for the development of digital computers, but the region of biasing currents in which the triggered oscillations occur is not wide enough for practical case.The purpose of this paper is to solve the above mentioned problem: a triggered oscillation circuit utilizing tunnel diodes which is biased non-linearly is proposed. The working properties of such a tunnel diode circuit have been investigated by point transformation and graphical methods. It is found that the operating region in which bistable states exist is wide enough. A simple expression for the normalized minimum biasing current θmin of bistable operation in obtained; θmin=(F(μ)-UF)/(F(μ)-1)≈1-2(UF-1)μ. The experimental results are in accord with the theoretical analyses. Some more complex circuits for triggered oscillation are also suggested.
THEORY OF THERMIONIC EMISSION (I)——A CRITICISM OF THE SEMI-CONDUCTOR MODEL OF THE OXIDE-COATED CATHODE
1974, 139 (5): 43-52. doi: 10.7498/aps.23.43
For over twenty years, in the course of our work on the oxide-coated cathodes, we have frequently come across many phenomena which can not be explained by the semi-conductor theory. This has led us to re-examine carefully most of the parameters, such as work functions, electrical conductivities, spectral absorption, concentration of excess barium, lattice structure,surface energy states, distribution of potentials in the coating, comparsion of thin film emission to coating emission, non-uniformity of emission, flicker noise, instability of impulse current, sparking etc. All these show that the oxide-coated cathode is not an n-type semi-conductor with excess barium as donor. A preliminary theory of surface emission centers which can explain many phenomena in the oxidecoated cathode is proposed.
1974, 139 (5): 53-63. doi: 10.7498/aps.23.53
The present paper is a criticism of the application of the monoatomic layer and simple dipote theory to thermionic emission. We have come to the following conclusions: (1) the existence of the monoatomic layer is conditional, it depends upon the temperature, surface structure and purity of the substrate as well as upon the vacuum environment; (2) the appearance, and sometimes disappearance, of the emission peaks is a problem for further study, and it can not be explained simply by the monoatomic layer and dipole theory; (3) the enhanced emission after adsorption of foreign atoms or molecules is not due to the formation of dipoles which lower the work function of the substrate, but comes from the valence electrons of the adsorbate, and (4) the "L" cathode is a Ba-O-W system, neither monoatomic nor monomolecular, and the dipole theory is not applicable here.
The reactions of Be9(d, p0)Be10(0), Be9(d, p1)Be10(3.368 MeV), Be9(d, t0)Be8(0), Be9(d, α0)Li7(0) and Be9(d, α1) Li7 (0.478 MeV) have been studied at deuteron bombarding energies from 0.1 to 2.5 MeV. The angular distributions of these five groups of outgoing particles have been measured respectively between θL = 10°and 155°at eleven bombarding energies of 0.150, 0.220, 0.401, 0.706, 1.005, 1.301, 1.484, 1.750, 2.000, 2.250 and 2.500 MeV. The excitation functions of the Be9 (d,p0) Be10 reaction have been measured at θL = 135° from Ed = 0.1 to 2.5 MeV, at θL = 95° from Ed = 0.1 to 2.2 MeV and at θL = 112.5° from Ed, = 0.5 to 2.5 MeV, respectively. By use of thicker targets (100-300μg/cm2) and at Ed = 1.2 MeV, the absolute cross sections of the Be9(d, p0)Be10 reaction were measured at θL = 135°and 112.5°; the results obtained are: σ(p0)(θL = 135°)= 1.60 mb/st and σ(p0)(θL = 112.5°)=1.55 mb/st. Thus, the behaviours of the cross sections of all these five groups of outgoing particles have been obtained in this energy range. These experimental results are discussed to some extent.