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In this work, [KNbO3]0.98-[A(Ni1/2Sn1/2)O3]0.02(A = Ba, Sr, Ca) photocatalytic materials were prepared using a solid-state method. The results show that changing the A-site doping element while keeping the B-site doping element constant leads to systematic variations in the band structure of KNbO3-based materials. The analysis reveals that as the ionic radius of the A-site dopant decreases, the conduction band and valence band of the samples exhibit an overall negative shift along the energy axis. The more negative conduction band energy level is favorable for electron reduction and hydrogen gas production. The hydrogen evolution rates of [KNbO3]0.98-[A(Ni1/2Sn1/2)O3]0.02(A = Ba, Sr, Ca) under simulated sunlight are 165.798 µmol/(g·h) (A = Ca), 151.697 µmol/(g·h) (A = Sr) and 119.487 µmol/(g·h) (A = Ba), respectively. [ABSTRACT FROM AUTHOR]

In the photocatalytic processes of ferroelectric semiconductor materials, how to induce a depolarized electric field (Edp) by polarization to reduce the electron–hole recombination rate is still a big problem. Here, the ABO3-type K0.5Na0.5NbO3 (KNN) material is modified by Nd and Ni elements at A/B sites to narrow the band gap and maintain the room-temperature ferroelectric behavior. The 0.96KNN–0.04NdNiO3 sample shows the narrowed band gap (∼2.75 eV) and high residual polarization value (∼11.56 μC cm−2). After high-field poling, the hydrogen production rate of the sample in the full spectrum reaches 926.28 μmol g−1 h−1, indicating an increase of approximately 5 times compared to the 170.45 μmol g−1 h−1 of the unpoled sample. The improved performance of photocatalytic hydrogen production mainly results from the reduction of band gap and the formation of Edp after polarization. The change in the position of the top of the valence band after sample polarization reveals that high-field poling can improve charge transport efficiency by energy band bending. [ABSTRACT FROM AUTHOR]

At present, the positioning control of the hydraulic support pushing systems in fully mechanized mining faces uses an electrohydraulic directional valve as the control component, while the current research mainly focuses on servo valves, proportional valves, high−speed on−off valves, and electromagnetic directional valves. At present, the positioning control for electrohydraulic directional valves is only a simple logical control. Therefore, in order to improve the positioning control accuracy of the hydraulic support pushing system, a predictive positioning control strategy based on iterative learning was designed. Firstly, mathematical modeling of the hydraulic support pulling process was carried out, and its state−space equation was established. Secondly, an iterative learning controller with a state observer was designed, in which the iterative learning method was used to predict the control advance in the positioning process, and the state observer was used to estimate the parameters that could not be measured by the system, so as to improve the control accuracy in the broaching process. Then, a SimulationX–Simulink joint simulation model of the position control system of a multi−cylinder pulling hydraulic support was built, and the designed iterative learning controller was compared with the BP neural network controller. Finally, a test platform for the hydraulic support pushing system was built, and the proposed control strategy was experimentally verified. The research results show that the iterative learning control strategy proposed for the electrohydraulic directional valve not only simplifies the design process of the controller but also has higher positioning control accuracy. The single−cylinder positioning control accuracy can be controlled within 10 mm, and the multi−cylinder coordinated positioning control accuracy can be controlled within 15 mm, which meets the accuracy requirements of the site. [ABSTRACT FROM AUTHOR]

Heterojunction construction is a significant method for enhancing the efficiency of electron–hole separation in photocatalysts, and it can be used to construct effective photocatalysts with visible light responses. In this study, g-C3N4 and KTaO3 compounds are prepared using phase sintering and solvothermal methods. Then, the classical self-assembly process produces the KTCN composite photocatalysts. The hydrogen production rate of the KTCN composite photocatalysts (~ 842.7 μmol g−1 h−1) is 4.25 times faster than that of the pure g-C3N4 (198.2 μmol g−1 h−1). The formation of the heterojunction reduces the photon-generated carrier’s recombination rate, thereby improving photocatalytic efficiency. The samples were further investigated by transient photoluminescence spectroscopy. The photoluminescence intensity of the composite photocatalyst was lower than that of g-C3N4, indicating that the electron–hole pair complexation efficiency was significantly reduced. The heterojunction of the composite photocatalyst can significantly enhance the photoexcited interfacial charge transfer and improve carrier–hole separation efficiency. Finally, this research offers an effective method for using composite photocatalysts in photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Aiming at the multi-row facility layout problems with uncertain number and position of vertical passages in rows, a layout optimization model was established with the goals of minimizing logistics intensity, minimizing the no-load intensity of handling equipment and maiming the interrelations between operation units, and a random-key BA was proposed for the model based on mapping rules. The idea of random-key coding was introduced into BA, and the mapping rules and steps from bat position based on random-key coding to combinational solution of multi-row facility layout were defined, so that the algorithm night be executed in continuous spaces without discrerization, and the layout schemes with different code length might be mapped in combinational spaces. Finally, the proposed random-key BA was used to solve an example of multi-row facility layout problem, and the advantages of the algorithm were proved. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pure κC and complex modifications increase gel strength and textural properties of FG. • The complex modified FG has the highest viscosity, gelation point, melting point. • The formed hydrogen bond and the isopeptide bond stabilized gels network structure. • The complex modified FG has the lowest free water mobility and in vitro digestibility. In this study, κ-carrageenan(κC) and Transglutaminase (TG) were used to modify fish gelatin (FG). Three types of modified gelatin groups FG-κC, FG-TG and FG-κC-TG were prepared. The results showed that the gel strength and textural properties of FG gels were greatly enhanced by κC modification and κC-TG complex modification, whilst pure TG modification weakened the gelling properties. And the pure 0.1 % κC modified FG had the highest gel strength and hardness, respectively. Rheological behavior showed that the complex modified FG samples had the highest viscosity, gelling points, melting points and G'∞. Fourier infrared spectra and LF-NMR analysis showed that κC and κC-TG modification respectively improved the contents of hydrogen and isopeptide that decreased the water mobility but stabilized the helical structure of gelatin gels. Fluorescence intensity showed that three types of modification decreased fluorescence intensity. While, the formation of aggregates and denser gel networks decreased in vitro digestibility of FG. [ABSTRACT FROM AUTHOR]