Social semiotics is now widely regarded as one of the leading research areas. This study is the first attempt to present a holistic overview of social semiotics based on the data in the Web of Science core collection database from 2001 to 2020. The study investigates, among other issues, social semiotics’ publishing tendency, the most productive authors, countries, institutions, and hotspots. The results exhibit a steady rise in its publications and citations. The current analysis verifies the growing quantitative and qualitative (...) research contributions and influences of this field. Furthermore, what the journals focus on are the innovative and contemporary themes, manifested predominantly in sign, multimodality, gender, experimental semiotics, advertising, culture, and social media, which involve a wide range of methodologies to make the research more acceptable and constructive. These results are expected to offer refreshing insights that inspire scholars in formulating scientific agendas and advising their research strategies, thereby facilitating substantial contributions to the domain. (shrink)

Pantographs are important devices on high-speed trains. When a train runs at a high speed, concave and convex parts of the train cause serious airflow disturbances and result in flow separation, eddy shedding, and breakdown. A strong fluctuation pressure field will be caused and transformed into aerodynamic noises. When high-speed trains reach 300 km/h, aerodynamic noises become the main noise source. Aerodynamic noises of pantographs occupy a large proportion in far-field aerodynamic noises of the whole train. Therefore, the problem of (...) aerodynamic noises for pantographs is outstanding among many aerodynamics problems. This paper applies Detached Eddy Simulation to conducting numerical simulations of flow fields around pantographs of high-speed trains which run in the open air. Time-domain characteristics, frequency-domain characteristics, and unsteady flow fields of aerodynamic noises for pantographs are obtained. The acoustic boundary element method is used to study noise radiation characteristics of pantographs. Results indicate that eddies with different rotation directions and different scales are in regions such as pantograph heads, hinge joints, bottom frames, and insulators, while larger eddies are on pantograph heads and bottom frames. These eddies affect fluctuation pressures of pantographs to form aerodynamic noise sources. Slide plates, pantograph heads, balance rods, insulators, bottom frames, and push rods are the main aerodynamic noise source of pantographs. Radiated energies of pantographs are mainly in mid-frequency and high-frequency bands. In high-frequency bands, the far-field aerodynamic noise of pantographs is mainly contributed by the pantograph head. Single-frequency noises are in the far-field aerodynamic noise of pantographs, where main frequencies are 293 Hz, 586 Hz, 880 Hz, and 1173 Hz. The farther the observed point is from the noise source, the faster the sound pressure attenuation will be. When the distance of two adjacent observed points is increased by double, the attenuation amplitude of sound pressure levels for pantographs is around 6.6 dB. (shrink)