Benefited from the optimized activity of active sites, adsorption energy and the proposed electron transfer property, the CoFe2O4 nanosheet with oxygen vacancies exhibited significantly enhanced water splitting catalytic performance.

Electrocatalytic nitrogen reduction reaction (NRR), as a green and sustainable method for ammonia synthesis, has become one of the candidates to substitute industrial Haber−Bosch ammonia synthesis in the near future. In this work, gold nanoparticles (Au NPs) were successfully anchored on bismuth sulfide nanorods (Bi 2 S 3 NRs), which acted as highly efficient electrocatalytic NRR catalysts. The N-philic nature of Bi and the unique mutual coordination of Au−S−Bi can greatly promote the nitrogen adsorption and form the intermediate product N 2 H*, achieving a boosted improvement in the NRR activity through a continuous hydrogenation reaction. Definitely, the as-synthesized Au(111)@Bi 2 S 3 nanorod catalyst exhibits an excellent NH 3 generation rate of 45.57 μg h −1 mg cat.−1 with a faradic efficiency of 3.10% at −0.8 V vs reversible hydrogen electrode. High stability and reproducibility are also demonstrated throughout the electrocatalytic NRR process. Density functional theory calculations were performed to further understand the NRR catalytic mechanism on the Au(111)@Bi 2 S 3 nanorods catalyst.

In this article, a novel multiple input multiple output (MIMO) antenna with compact structure and diverse radiation patterns is designed for a wireless communication device. Four monopole antenna elements are placed orthogonally at the corner of the substrate. A decoupling structure composed of a circular patch and 4 L‐shaped branches placed counterclockwise is printed on the upper surface of the substrate to reduce coupling between antenna elements. Due to the surface current on the circular parasitic patch, which was acquired by coupling with the monopole antenna, the MIMO antenna exhibits an omnidirectional radiation pattern at low frequencies and a directional radiation pattern at high frequencies. In order to verify the accuracy of theoretical analysis and simulated results, the proposed antenna with a compact size of 30 mm × 30 mm is fabricated and measured. The measured results show that the overlapping bandwidths (S11 ≤ −10 dB) are 28.8% from 4.58 to 6.12 GHz and over 4.02 dBi gain. Furthermore, the measured results of pattern diversity are basically consistent with the simulated results, and the measured isolation is up to 15.4 dB, which suggest that the presented antenna can be applied to WLAN/5G/WiFi wireless communication.

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In this paper, evaporation of sessile water droplets containing fluorescent polystyrene (PS) microparticles on polydimethylsiloxane (PDMS) surfaces with different curing ratios was studied experimentally using laser confocal microscopy. At the beginning, there were some microparticles located at the contact line and some microparticles moved towards the line. Due to contact angle hysteresis, at first both the contact line and the microparticles were pinned. With the depinning contact line, the microparticles moved together spontaneously. Using the software ImageJ, the location of contact lines at different time were acquired and the circle centers and radii of the contact lines were obtained via the least square method. Then the average distance of two neighbor contact lines at a certain time interval was obtained to characterize the motion of the contact line. Fitting the distance-time curve at the depinning contact line stage with polynomials and differentiating the polynomials with time, we obtained the velocity and acceleration of both the contact line and the microparticles located at the line. The velocity and the maximum acceleration were, respectively, of the orders of 1 µm/s and 20-200 nm/s 2 , indicating that the motion of the microparticles located at the depinning contact line was quasi-static. Finally, we presented a theoretical model to describe the quasi-static process, which may help in understanding both self-pinning and depinning of microparticles.