Calculation of the external quality factor of the high power input coupler for the BEPC Ⅱ superconducting cavity

It is very important to predict the coupling between the cavity and the high power input source in the coupler design. In this paper, a time domain method is used to calculate the external quality factor Qext for the BEPC Ⅱ superconducting cavity. A comparison between simulation results and experimental results is presented. The results of simulation and measurement of Qext have a good agreement within an error of 10%.The geometry parameters related with Qext are also studied.     

A Note on the Domination Number of Triangulations

In this note, we prove that every triangulation G on any closed surface has domination number at most . This unifies some results on the domination number of a triangulation on a closed surface.     

Psychological experiments on listener envelopment when both the early-to-late sound level and directional late energy ratios are varied, and consideration of calculated LEV in actual halls

The purposes of this paper are to clarify the relation between listener envelopment (LEV) and two physical factors, namely, early-to-late sound level C₈₀ and directional late energy ratios (DLRs), and to demonstrate the significance of evaluating LEV using C₈₀ and DLRs. Firstly, two psychological experiments are performed. In the first experiment, the results show that the previous findings about the effects of late reflections from lateral, overhead, and behind the listener on LEV are valid when they also consist of plural directional energy components, as are found in real sound fields. In the second experiment, the relational equation among LEV, C₈₀, and DLRs is derived from results when the physical factors are simultaneously varied. Secondly, psychological scores for LEV are calculated in actual halls by applying measured values for C₈₀ and DLRs to the equation. The results show that the differences in LEV among different seating positions and in the spatial uniformity of LEV among different halls are expected to be significantly large depending on the values of C₈₀ and DLRs. This suggests the significance of evaluating LEV by means of C₈₀ and DLRs.     

Thermodynamics of polymeric fluids – effect of volume on the configurational entropy of chain molecules

Various conformation‐dependent properties of chain molecules have been successfully treated within the rotational isomeric state approximation. The conformation entropy is one of such properties which can be readily defined by the partition function, the sum of all possible configurations of the chain. Flexible polymers often exhibit crystallization and in some cases liquid‐crystallization as well. In these first‐order transitions, changes in the spatial arrangement of polymer chains are considered to be a major factor involved. In order to explicitly determine the conformational contribution to the melting entropy, the latent entropy observed under the isobaric condition must be corrected for the volume change. The entropy separation involves a hypothetical assumption that the volume of the isotropic fluid may be compressed to that of the solid state without affecting the configurational part of the entropy of molecules. Finally thermodynamic significance of the conformation entropy in these transitions is emphasized on the basis of the critical studies of the entropy‐volume relation of chain molecules in the liquid state.