Acta Physica Sinica -

ON THE SUPERSONIC MOTION OF CHAPLYGIN GAS

CHUANG FENG-KAN — 1955-01-05

Author(s): CHUANG FENG-KAN

In this paper the approximation which was originally introduced by Chaplygin in his famous paper "on gas jet" for the treatment of subsonic flow is extended to the supersonic motion. Four typical initial value problems are solved using hodograph variables, and the analytical forms of the solutions are obtained. The approximate solutions of supersonic flow given by Christianovich is extended in this paper to slightly supersonic flow. Finally the relation between the Christianovich's approximate method and the general treatment presented here is studied.

Acta Physica Sinica. 1955 11(2): 107-124. Published 1955-01-05

SOME PRACTICAL PROBLEMS ARISING FROM THE ADOPTION OF THE ABSOLUTE SCALE OF TEMPERATURE AS STANDARD

WANG JWU-SHI — 1955-01-05

Author(s): WANG JWU-SHI

Some practical problems arising from the adoption of the absolute scale ol temperature as standard in place of the Celsius scale are discussed. The absolute scale is fixed by assigning a numerical value (say T3=273.1700) to the triple point of water. The problems 'considered include the correction of gas thermometer readings, the specification of: the platinum resistance thermometer and of the platinum thermocouple. It is pointed out that, when the absolute scale has been chosen as standard, the determination of the absolute temperature of the ice point and the correction of gas thermometers become one and the same task. It is further pointed out, that the accuracy in the experimental determination of the absolute temperature will be greatly increased.

Acta Physica Sinica. 1955 11(2): 125-132. Published 1955-01-05

THE ANOMALOUS MAGNETIC MOMENT OF NUCLEONS

Yü MIN — 1955-01-05

Author(s): Yü MIN

The nucleon magnetic moments and the neutron-electron interaction potential have been calculated using the theory of pseudo-scalar mesons with pseudo-vector coupling. The divergence in the neutron-electron interaction is removed after the vacuum polarization effect due to virtual mesons has been taken into account. The final result is the same as in the case of pseudo-scalar coupling.

Acta Physica Sinica. 1955 11(2): 133-142. Published 1955-01-05

A NEW METHOD OF CALCULATION FOR THE STRUCTURE OF MOLECULES

PENC HUAN-WU — 1955-01-05

Author(s): PENC HUAN-WU

A new method of calculation of the self-consistent field type is outlined for studying the electronic structure of molecules. In this method the fundamental wave functions refer to individual bonds of the molecule and not to individual electrons as in the existing methods of atomic orbitals and molecular orbitals.

Acta Physica Sinica. 1955 11(2): 143-148. Published 1955-01-05

THE RADIATIVE CORRECTIONS TO THE SCATTERING OF ELECTRONS AND POSITRONS

KING SING-NAN — 1955-01-05

Author(s): KING SING-NAN

With the Mφller's theory of scattering between the electrons and the Dirac's hole theory, Bhabha has obtained the formula for the scattering of the electrons and the positrons. The experimental evidence of this phenomenon was discovered by Ho (何泽慧), and she has studied this phenomenon by means of the β+-radioactivity of the β+ sources such as Mn52, and F18 in the cloud chamber. The comparison of the theory and the experiment was done (see reference [2], [3], [4], [5] and [6].) by Ho, O. Ritter et al, R. R. Roy and L. Groven, G. R. Hoke and A. Ashkin et al.The purpose of the present work is to show the effect of the radiative corrections to the scattering of the electrons and the positrons by the method in the quantum electrodynamics developed by S. Tomonaga, J. Schwinger, R. P. Feynman and F. J. Dyson.In the above-mentioned electron and positron scattering experiments, the contributions to the scattering cross-section are mostly due to the positrons of low energies (about 0.1 to 0.2 Mev). In this energy range, the exchange effect in Bhabha's theory is small. In this work for the radiative corrections to the scattering of the electrons and the positrons, we have neglected this exchange effect. The ratio of the correction of the scattering cross-section due to the radiative corrections to the scattering cross-section of Bhabha's theory at this energy range does not exceed 1%. For experiments of the low energy positrons and of the higher energy positrons (e.g positrons with energies of 0.5 Mev to 1 Mev as in the experiment of Ashkin et al) with small exchanges of energy between the electrons and the positrons during scattering, our calculation is adequate. But for positrons of higher energies and with large exchanges during scattering, our calculation should be improved by considering the exchange effect.

Acta Physica Sinica. 1955 11(2): 149-162. Published 1955-01-05

A THERMODYNAMICAL STUDY OF INTERNAL FRICTION

CHENG KAI-CHIA — 1955-01-05

Author(s): CHENG KAI-CHIA

Detailed theoretical investigations on the nature of internal friction of linear type have been made by Zener and others. It appears that their results are not systemmatic enough owing to the lack of generality. In particular, very little has been attempted to the illucidation of the nature of mutual interactions due to causes which give rise to internal friction.In this paper a theory is proposed based on the general theory of thermodynamics ol irreversilc processes together with the Boltzmann superposition principle. A comparison is made of the results of both theories. It is found that definite variance exists in the instances in which the mutual interactions become predominant. It would therefore appeal to further experimental demonstrations. In view of the recent rapid progresses in the experimental studies of anomalous and amplitude dependent internal frictions, it would be of interest to carry out a programm of study of the internal friction of non-linear type by the procedures similar to that proposed in the text.

Acta Physica Sinica. 1955 11(2): 163-178. Published 1955-01-05

A MAGNETIC INTERNAL FRICTION PEAK IN NICKEL UNDER ALTERNATING MAGNETIC FIELD

KAREL MISIEK — 1955-01-05

Author(s): KAREL MISIEK

The coupling between elastic and magnetic phenomena in ferro-magnetic materials often gives rise to internal friction. In previous studies on magnetoelastic internal frictions, the applied magnetic field was mostly static. In the present experiment, nickel specimen was made to vibrate in torsion under an alternating magnetic field, and a pronounced internal friction peak was observed when internal friction was plotted as a function of the alternating magnetic field strength. This peak did not appear under similar conditions when using a static magnetic field. The position of the peak was shifted toward the side of a higher magnetic field when the nickel specimen was either cold-worked or contained carbon; and it was shifted toward the side of a lower magnetic field when the specimen was previously annealed at an elevated temperature. The height of the peak was considerably raised with an increase of vibrating frequency.A qualitative explanation of this peak is given on the basis of reversible and irreversible processes occuring at different stages of the magnetization curve of nickel. Factors affecting this peak arc discussed.

Acta Physica Sinica. 1955 11(2): 179-190. Published 1955-01-05