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Hollow microbeads, derived from fly ash emitted by power plants, are hollow microbeads composed of various compounds including SiO2 and Al2O3. These microspheres exhibit a high specific surface area and stable chemical properties. In this work, HM-MoS2 was synthesized through a two-step hydrothermal method to address the issues of low adsorption efficiency and high operational costs associated with the utilization of hollow microbeads in actual power plant applications. The experiments demonstrated that under simulated power plant flue gas conditions, the adsorption efficiency of HM-15 for elemental mercury (Hg0) exceeded 96%. Additionally, HM-15 displayed resistance to SO2 and NO gases, indicating its potential as a mercury adsorbent material with promising industrial applications.

In the past decades, microfluidic chips have been one of the hottest research topics in the "lab-on-a-chip" field. However, it is still a challenge for design the perfect microchannels with high functional integration, complex geometry, and high production efficiency. This review paper provides a comprehensive overview of microfluidic structural models and designs, manufacturing techniques, and bonding methods. The effect of three types of microfluidic channel structure models and their configuration parameters on the fluid behaviors of microfluidics was investigated. Surface-to-volume ratio of the flow channel is a critical parameter for determining the mixing and diffusion capabilities of the microfluidic devices (MDs). Thereafter, the main manufacturing techniques for microstructures were discussed, including etching, photolithography, soft lithography, molding, mechanical micro-machining, laser beam micromachining, printing, and 3D printing. We performed a statistical analysis to discuss the relative advantages and disadvantages of these manufacturing methods. In addition, the current bonding methods for MDs were also summarized, including thermal bonding, solution adhesive bonding, dry adhesive bonding, plasma bonding, and anodic bonding. a comparison of different bonding methods was presented to provide a reference to select a suitable bonding method for the assembly of microfluidic device. Finally, the tendencies and challenges of microchannel manufacturing were discussed, and the prospects were also provided. [ABSTRACT FROM AUTHOR]

The separation of cenospheres is an important method for fly ash recycling, and there is no efficient and less polluting method available for separating cenospheres. This paper proposes the dry separation of cenospheres using a cyclone separator, which utilizes the small density of cenospheres as a feature to separate them. The corresponding numerical simulations of the cyclone separator model used to separate the cenospheres were carried out by a CFD analysis, after which the size of the radius of the upper discharge opening and the height of the sloping wall of the cyclone separator were analyzed by simulation; the effect of the incident velocity on the Newton's efficiency of the separation of the cenospheres was also analyzed. The simulation results indicate that the Newton's efficiency can reach 0.55 when the radius of the upper feed port is 90 mm, the height of the inclined wall is 400 mm, and the incident speed is 2.5 m/s. [ABSTRACT FROM AUTHOR]

Pitch system is an essential subsystem of a wind turbine, which is to efficiently capture and maximize the utilization of wind energy by controlling the rotation of the blades. Its safety and stability directly affect the operation of wind farm, but the complex internal mechanics and control system makes pitch system very susceptible to failure. This paper first summarized fault diagnosis and fault prediction about pitch system of wind turbine. We were briefly introduced the main faults of electric-driven and hydraulic-driven pitch systems, the sources of diagnostic data, and the methods pre-processing. Then, four types of fault diagnosis methods and three fault prediction methods were discussed to provide a valuable guidance for the maintenance of pitch systems. Finally, the prospect on the future development of fault diagnosis and fault prediction techniques about pitch system was suggested to further improve the safety of wind turbines. [ABSTRACT FROM AUTHOR]

The MgO‐MoO3 system shows significant potential for applications in microwave dielectric ceramics. However, the formation mechanism, crystal structures, and microwave dielectric properties of this system have not been systematically investigated. This work aims to comprehensively study the crystal structures, phase transitions, and microwave dielectric properties of compounds in the MgO‐MoO3 system. In particular, the research delves into the unexplored transformation mechanism from β‐MgMo2O7 to α‐MgMo2O7 and MgMoO4. As a result, the three compounds exhibiting favorable microwave dielectric properties have been successfully fabricated. These compounds can be effectively sintered at temperatures ranging from 685 to 900°C and exhibited dielectric constants (εr) ranging from 5.41 to 6.89, as well as Qf values ranging from 100 000 to 130 000 GHz. Additionally, prototype microstrip antennas are designed and fabricated using β‐MgMo2O7 and MgMoO4 ceramics as substrates. The obtained antenna's performance is excellent, with S11 values below −30 dB and a gain exceeding 6 dB at 5.8 GHz, highlighting the potential of the developed ceramics for practical applications in microwave devices. [ABSTRACT FROM AUTHOR]

Spherical diamond particles have great potential as additive materials for improving lubricity of lubricants, and yet the complicated preparation process is difficult to meet the current industrial demand. Therefore, a novel method was proposed to deposit mass spherical diamond on the discontinuous silicon nitride (Si3N4) powder substrate by the hot filament chemical vapor deposition method. The results revealed that the substrate was covered by the spherical diamond grains with a diameter of about 20 μm. Thereafter, they were used as lubricant additives to examine the tribological and grinding properties. Therein, the Si3N4 surface had a remarkable reduction in surface roughness by a factor of 124.62% as compared to that without spherical diamond powder, while GCr15 alloy had a 31.17% increase under the same condition. Hence, our method provides a promising way to deposit the mass spherical diamond powder that might become a great abrasive material for machining the ceramic. [ABSTRACT FROM AUTHOR]

There have been huge achievements of all‐perovskite tandem solar cells, which recently realized the highest power conversion efficiency of 24.8%. However, the complex device structure and complicated manufacture processes severely restrict the further development of all‐perovskite tandem solar cells. In this work, we successfully fabricated high‐efficiency hole transport material‐free (HTM‐free) Sn−Pb alloyed narrow bandgap perovskite solar cells (PSCs) by introducing guanidinium thiocyanate (GASCN) and hydroiodic acid (HI) into the perovskite precursor solution. GASCN and HI play a positive synergy effect during perovskite crystallization process resulting in larger grain size, fewer surface defects, and lower trap density to suppress the Sn2+ oxidation degradation. Furthermore, they could effectively adjust the energy level of perovskite materials, reduce the energy level difference between perovskite and ITO resulting in more efficiently transport of free hole charge carriers. As a result, with adding GASCN and HI, the achieved highest power conversion efficiency of HTM‐free devices increased from 12.58% to 17.85%, which is one of the highest PCEs among all values reported to date for the HTM‐free narrow‐bandgap (1.2–1.4 eV) Sn−Pb binary PSCs. Moreover, the optimized device shows improved environmental stability. Our additive strategy manifests a remarkable step towards the facile, cost‐efficient fabrication of HTM‐free perovskite‐based tandem solar cells with both high efficiency and simple fabrication process. [ABSTRACT FROM AUTHOR]

With the development of 5G/6G communication, the requirements of portable devices for miniaturization and multifunction make low‐temperature co‐fired ceramic (LTCC) more and more important. In the area of high‐frequency high‐density passive integration, microwave dielectric ceramics with a low dielectric loss and high thermal conductivity are urgently needed to ensure the effective signals transmission and system reliability. However, most microwave dielectric ceramics with a low dielectric loss were not applicable for the LTCC technology due to the high sintering temperature. In this work, a series of MgO‐based ceramics [(100 − x) wt.% MgO–x wt.% (0.2SrF2–0.8LiF) (x = 5,7,10)] were prepared by solid‐state reaction method. The addition of sintering aid 0.2SrF2–0.8LiF (S2L8) decreased the sintering temperature below 880°C without degrading the microwave dielectric properties of ceramics. Microwave dielectric properties of ceramics, including quality factor Q × f, relative permittivity εr, and temperature coefficient of resonant frequency τf, were investigated to find the optimum composition and sintering temperature. In general, MgO–7 wt.% S2L8 ceramic sintered at 860°C exhibits outstanding properties of Q × f = 180 233 GHz, εr = 9.11, τf = −40.33 ppm/°C, and a high thermal conductivity of 24.02 W/(m K). This series of ceramics are suitable to be co‐fired with Ag electrodes. With all those great properties, this series of MgO‐based ceramics are expected to be the candidates for LTCC applications in 5G/6G technology. [ABSTRACT FROM AUTHOR]