Effect of Earth-Moon's gravity on TianQin's range acceleration noise. II. Impact of orbit selection

The paper is a sequel to our previous work (Zhang et al. Phys. Rev. D 103, 062001 (2021)). For proposed geocentric space-based gravitational wave detectors such as TianQin, gLISA, and GADFLI, the gravity-field disturbances, i.e., the so called ``orbital noise'', from the Earth-Moon system on the sensitive intersatellite laser interferometric measurements should be carefully evaluated and taken into account in the concept studies. Based on TianQin, we investigate how the effect, in terms of frequency spectra, varies with different choices of orbital orientations and radii through single-variable studies, and present the corresponding roll-off frequencies that may set the lower bounds of the targeted detection bands. The results, including the special cases of geostationary orbits (gLISA/GADFLI) and repeat orbits, can provide a useful input to orbit and constellation design for future geocentric missions.Comment: 8 pages, 9 figure

The Development of Measurement Scale for Entertainment Tourism Experience: A Case Study in Macau

Tourism and entertainment industry is an important component in the world’s service sector. Entertainment tourism is receiving more attention, not only from practitioners, but also from academics. This study develops a scale to measure entertainment tourism experience in Macau from the consumers’ perspective. Entertainment tourism in this study is operationalized by Learning, Enjoyment, Escape, Refreshment, Novelty, Involvement, and Local culture. After examining the reliability of the measurement scale, this study applies factor analysis and multidimensional scaling to establish survey instrument. The reliability and validity of the scale are confirmed through the first and the second order confirmatory factor analysis. This study provides theoretical and practical implications and recommendations to entertainment stakeholders, including entertainment suppliers and government, to promote entertainment tourism practices in Macau

Impulsive Vaccination SEIR Model with Nonlinear Incidence Rate and Time Delay

This paper aims to discuss the delay epidemic model with vertical transmission, constant input, and nonlinear incidence. Some sufficient conditions are given to guarantee the existence and global attractiveness of the infection-free periodic solution and the uniform persistence of the addressed model with time delay. Finally, a numerical example is given to demonstrate the effectiveness of the proposed results

Effect of solar free oscillations on TianQin's range acceleration noise

TianQin is a proposed space-based gravitational-wave detector mission to be deployed and operated in high Earth orbits. As a sequel to [Zhang et al. Phys. Rev. D 103, 062001 (2021)], we investigate a type of ``orbital noise'' in TianQin's range acceleration that is caused by gravitational perturbation associated with solar free oscillations. Frequencies of such oscillations are typically within TianQin's measurement band of 0.1 mHz--1 Hz, and the disturbance level needs careful assessment. By using high-precision orbit propagation and adding the Sun's time-variable oblateness $J_2$ to detailed gravity-field models, we examine the effect in the frequency domain and show that the solar free oscillation noise is expected to be two orders of magnitude lower than the noise requirement on single links and hence has little impact on the mission.Comment: 10 pages, 5 figure