Search

Electric water pumps (EWPs) are characterized by small sizes and variable operating conditions. Efficient operation of such a pump is important for the whole thermal management system. Here, comprehensive hydraulic optimization was performed to improve the performance of an EWP. The computational fluid dynamics technique was used to assist in the optimization. The numerical scheme was validated using experimental data. Variations in the blade number, blade profile, and blade inlet edge were implemented. The results showed that solely increasing the blade number leads to an increase in the pump head but cannot guarantee high pump efficiency. A combination of adjusting the blade wrap angle and extending the blade inlet edge toward the pump inlet promotes increases in both the pump head and efficiency. With the improvement in pump performance, the characteristics of the flow field alter remarkably. The pressure at the blade inlet is reduced, and the turbulent kinetic energy near the impeller blade decreases overall. [ABSTRACT FROM AUTHOR]

As one of the indispensable instruments in many fields, optical tweezers are extensively utilized in micromanipulation. Vortex beams and diverse structured light fields make multi-trap optical tweezers possible. Here, the radiation forces of Laguerre-Gaussian (LG) composite vortex beams exerting on a Rayleigh dielectric particle are investigated. Our results show that the multi-trap optical tweezers can be produced by the Laguerre-Gaussian composite vortex beams, which can trap the particles with both high and low refractive indices in the focus plane at multiple positions. Moreover, by changing the orbital angular momentum (OAM) quantum numbers and energy ratios of the Laguerre-Gaussian modes participated in the superposition, the quantities of the optical traps and the distances between multiple traps can be conveniently adjusted. Our beams can be generated by several methods, which provides more convenience for the creation of multiple optical traps. The results presented in this work are potential in optical micromanipulation, as well as other applications in biology and chemistry. • The radiation forces of Laguerre-Gaussian composite vortex beams are investigated. • The both high- and low-index particles can be trapped at multiple positions. • The quantities and the distributions of the multiple traps can be adjusted. [ABSTRACT FROM AUTHOR]

The weight–length relationship (WLR) of fish is a crucial tool in fish biology research and has received extensive attention. However, fish growth is influenced by many factors, and the WLR also changes accordingly. Our aim was to investigate how fish body shape is affected by various factors by analyzing the existing parameters of the relationship between fish body length and weight. We analyzed 198,354 fish specimens belonging to 402 species of 82 families in China and investigated the change of fish body shape in the function of their ecology. Herbivorous fish tended to be shorter and fatter than carnivorous fish, and omnivorous fish fall somewhere in between. This difference could be due to variations in feeding habits and the availability of food sources. Additionally, fish living in lentic waters tended to have a shorter and fatter body shape compared to those living in lotic waters. This could be attributed to differences in swimming behavior in these environments. Furthermore, our results showed that the b value decreased as altitude increased, and fish tended to be thinner and longer due to lower oxygen and temperature levels in high-altitude waters. Overall, our study provides valuable insights into the WLR of fish and the impact of multiple factors on fish body shape. [ABSTRACT FROM AUTHOR]

Owe to the ability of supporting propagating surface plasmons, silver nanowire can be decent candidate as optical nanoantenna to modulate the polarization property of nano-emitters. Here, we created a quantum dots and silver nanowire coupling system to implement the controllable polarization dependence of this antenna effect. Several basic modes are mainly explored with both positive and negative excitation and observation directions. For the contrast excitation directions, both the center and the end fluorescence spots have reverse polarization dependence characterizations. While the controllable polarization dependence only appears at the center spot for the different observation angles. Based on these modes, diverse polarization dependence properties can be extended flexibly. The reasons for the phenomena are explained using the theoretical simulation. The numerical calculation shows the silver nanowire can act both optical receiving antenna and transmitting antenna in this process. Achieving on the controllable polarization dependence, our results are useful in the investigation about the coupling of nano-emitters and optical antenna. • The controllable polarization dependence is implemented in our coupling system. • Two modes with reverse excitation and observation are explored experimentally. • Reverse dependence for contrast excitation arises at both the center and the end. • The controllable dependence appears at the center for reverse observation angles. • The reasons for the phenomena are explained using the theoretical simulation. [ABSTRACT FROM AUTHOR]

Based on the extended Huygens–Fresnel principle, an analytical expression for the cross-spectral density of optical coherence lattices (OCL) in oceanic turbulence is derived. With the help of this expression, we investigate the propagation of OCL in oceanic turbulence. In order to increase underwater optical communication distance, we investigated the effects of source parameters, such as lattices constant, wavelength and beam width, on intensity distribution of OCL in oceanic turbulence. Results indicate that the light intensity received by receiver increases with the increase of lattice constant, the increase of beam width and the decrease of wavelength, which may have some potential applications in underwater optical communication. [ABSTRACT FROM AUTHOR]