Vol. 10, No. 1 (1954)
It is pointed out that the quantum-mechanical Boltzmann H theorem in the restricted sense (i.e. with explicit consideration of the statistics of the particles constituting the system and their interactions) does not lead directly to the distribution laws for the particles among their various states as is commonly believed, but to the equality of the probability for all states belonging to the system as a whole if the system is isolated, (or to the Boltzmann factor for the probabilities of states belonging to a system at constant temperature), in agreement with the result of the generalized quantum-mechanical H theorem as given by Pauli. The distribution laws for the particles among their various states may of course be deduced from the latter.In the course of proof, we have also introduced the following minor improvements:(i) To avoid conservation of energy in microscopic processes which lead to changes in the states of the particles and thus to equilibrium, we let our system be in interaction with a heat reservoir, so that energy may be supplied by or given to it. This is tauto-mount to changing the study of the entropy for an isolated system to that of the free energy for a system at constant temperature.(ii) Interaction energies between the particles which affect the total energy of the system and thus the distribution laws for the particles among their various states are included.
Solids can not be infinitely stressed under all stress states, thus only certain portion of the stress space has significance for solids. The shape, size and structure of this portion of stress space is closely connected with the mechanical properties of solids. By "realistic stress space of solids", is meant this portion of the stress space. Although some aspects of this problem had been investigated by some authors, there exists even no definite concept regarding the shape, structure and properties of the realistic stress space of solids up to this date.
1954, 23 (1): 43-56. doi: 10.7498/aps.10.43
This paper presents a method by which a complete set of static characteristics of a power tube, including that of positive grid region, can be seen all at once on the screen of a cathode ray oscilloscope. Use is made of pulse-technique and intensity modulation of a cathode ray tube. Circuits are given and explained for observing plate characteristics on the plate current-plate voltage plane as well as constant current contours on the plate voltage-grid voltage plane, the former being shown in fig. 11 and the latter in fig 21. It is believed that the method here described will be of some help to tube manufacturers.
1954, 23 (1): 71-88. doi: 10.7498/aps.10.71
The equations of the plane, laminar compressible boundary layer flow past a plane or slightly curved wall