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The impedance matching is essential in producing high-intensity acoustic waves. This paper studies the impedance calculation methods of modulators and double-chamber Helmholtz resonators based on fluid mechanics, aeroacoustics, and electro-acoustic analogy principles. The results: ① The impedance expression of the resonators is derived. ② The impedance variation law of the chamber volume, the stator size, the air supply pressure, the air supply flow, and the working frequency is calculated. ③ The impedance-matching design scheme of the two-chamber Helmholtz low frequency and high acoustic intensity generator is given. Based on the experimental results of the high acoustic intensity generating device that the author has manufactured in the closed space, the correctness of the impedance calculation and matching design scheme in this paper is verified. This method has guiding significance for the design of high-intensity acoustic generating devices in confined space. [ABSTRACT FROM AUTHOR]

The high-intensity low-frequency acoustic sources have essential applications in acoustic biological effects research, airport bird repelling, and boiler ash removal. However, generating high-intensity low-frequency acoustic waves in open space is difficult. In this paper, a low-frequency acoustic generator with a resonant cavity used to enhance the acoustic intensity in open space was developed, which is an aerodynamic acoustic generator to radiates a high-intensity acoustic wave of 52Hz. Some experiments were carried out to measure this generator's internal flow field and radiated acoustic field characteristics, including the propagation characteristics at 100m. The experimental results show that the resonant enhancement effect is presented near the predetermined resonance frequency, and the enhanced value is about 4dB. The acoustic intensity for 52Hz at 1m position is 124dB. By combining the Helmholtz resonator with the airflow modulator, the airflow resonance in the resonator enhances the air pressure pulsation inside the chamber and increases the disturbance of acoustic radiation to the air. So as to improve the sound intensity and radiation efficiency in the low-frequency range. [ABSTRACT FROM AUTHOR]

[Purpose/significance] This research attempts to investigate the impact of personality traits on the adoption and time spending of mobile photography apps, mobile game apps, mobile shopping apps and mobile video apps. [Method/process] 520 valid samples were collected by questionnaires and further analyzed by using the variance analysis and correlation analysis. [Result/conclusion] The result shows that agreeableness is positively associated with the adoption of mobile photography apps; conscientiousness is negatively associated with the adoption of mobile game apps; extraversion is positively associated with the adoption of mobile shopping apps, mobile video apps and mobile photography apps; neuroticism has negative association with mobile shopping apps, mobile video apps; agreeableness has positive association with time spending on mobile video apps; conscientiousness has negative association with time spending on mobile game apps; extraversion is positively associated with time spending on mobile video apps, mobile photography apps; neuroticism has negative association with time spending on mobile video apps.