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Photocatalysis has been regarded as a kind of environmentally friendly advanced oxidation process to eliminate pollutants. In this work, Phosphorus-doped carbon nitride tube (PCN) was synthesized via a hydrothermal calcination method and applied to degrade tetracycline (TC) through combing with peroxydisulfate (PDS) under visible light irradiation. Experimental results showed that the optimized catalysts PCN-5 exhibited superior degradation performance and reusability for TC degradation. 96.4% TC could be degraded for optimal PCN-5 with 0.3 g·L−1 catalysts and 1.0 g·L−1 PDS under visible light within 60 min. In addition, the degradation rate constant for TC of PCN + PDS + Vis system was still above 85% after five uses. Radical trapping experiment indicating that O2·− is the dominant radical for TC degradation. The findings of this work revealed the potential application of the PCN + PDS + Vis system toward degrading contaminants in wastewater. HIGHLIGHTS Phosphorus-doped carbon nitride tube was successfully synthesized.; PCN-5 + PDS + Vis system exhibited excellent TC degradation performance and reusability.; O2·− is the dominant radical for TC degradation.

In this paper, both experimental and theoretical studies were conducted to investigate the bonding interface formation, microstructure evolution, and the interface strength of an AA6061/AZ31B alloy cladding plate fabricated by explosive welding. The evolution of microstructures including adiabatic shear bands (ASBs) structure, recrystallized grains, and elongated grains were analyzed using optical microscope (OM), electron back scatter diffraction (EBSD), and transmission electron microscope (TEM). A model was also proposed to study the ASBs formation and recrystallized grains in the ASBs. In the study, during explosive welding, a periodic wavy bonding interface was observed and the formation of such an interface was found due to the periodic jetting caused by the high impact stresses at the impact points during welding. The ASBs were found formed along the directions where the stress waves were concentrated due to high energy accumulation. Near the bonding interface, many crystallized grains were found in the AZ31B alloy plate, while elongated grains were dominant in the AA6061 alloy plate. Difference in the crystal structure of the Al and Mg alloy was believed to be the reason causing such microstructure evolution difference. Nanoindentation tests on the ASBs showed that, due to the existence of fine grains resulted from the recrystallization in the ASBs structure, the hardness of the ASBs structure (1.22 GPa) was higher than that of its surrounding structure. The shear strength of the bonding interface of the explosively-welded AA6061/AZ31B cladding plate can reach up to 201.2 MPa.

In this study, the process of explosive welding of Mg/Al plate is represented, and the interfacial behavior of two metals is researched. The objective of this work is to investigate the factors that affect the quality of explosive bonding and the distribution of physical parameters on the collision. A finite difference engineering package with smoothed particle hydrodynamics method is used to model the oblique impact of a thin flyer plate (Al) on a relatively thick base plate (Mg). Wavy interface and jetting phenomenon, which existed in the experiment, are well reproduced in the simulation. The contours of pressure, shear stress, velocity, and effective plastic strain of magnesium and aluminum are also distinctly described. The bonding turns out to be a possible solid-state welding process. The effective plastic strain exceeds a minimum value, and the shear stress is just the opposite sign in this simulation where available bonding occurred. Wave formation appears to be the result of variation in the velocity distribution on the interface and periodic disturbances of magnesium and aluminum. A transition from straight to wave occurs along the interface. High values of plastic strain of two metals are predicted on the interface.

Magnesium alloys AZ31B plates and pure titanium TA2 plates were bonded successfully through explosive welding. The microstructure and composition of the interface were examined by optical microscope (OM), scanning electron microscopy (SEM) and energy dispersive spectroscope (EDS). To explore the process of element diffusion between AZ31B and TA2, the composite plates were annealed at different temperatures. Furthermore, the mechanical behavior of the composite plates was evaluated. The results show that straight and wavy interfaces coexist on the bonding area. The element diffusion becomes obvious when heating at 450 and 490 °C for 4 and 8 h. The hardness of AZ31B and TA2 is increased significantly due to the plastic deformation and the strain hardening. The mechanical properties of the composite plates are significantly improved compared with those of base plate AZ31B.

Lithium metal anode has been considered as an ideal anode for the next generation lithium batteries owing to its high energy density. However, its practical application is still limited by the low Coulombic efficiency and poor safety performance due to the lithium dendrites caused by uncontrollable lithium deposition and unstable solid electrolyte interphase. In this work, we report for the first time the in-situ synthesis of S-doped carbon nanospheres with ordered mesoporous channels used as the functional scaffold for safe and stable lithium metal anode. S-doping, large surface area and ordered mesoporous structure of the carbon spheres provide homogenous nucleation sites, regulated local current density and facilitated mass transport, which induce uniform lithium nucleation and the subsequent dendrite-free growth. As a result, the fabricated anode exhibits high Coulombic efficiency up to ~97.5% within 220 cycles. The symmetric cell also presents stable potential hysteresis below 15 mV with ultralong cycling life up to 1600 h at a current density of 0.5 mA cm-2. Full cell coupled with commercial LiFePO4 as cathode delivers a high reversible capacity of ~135.0 mAh g-1 after 300 cycles at 1 C, showing high potential in practical application as stable lithium metal anodes.

In order to study the fatigue reliability of pre-stressed concrete simple-supported beams that considered the effect of size effect, using the existing method to check the fatigue reliability of the test-piece. The fatigue test of three pre-stressed concrete simple beams was carried on, which the size of the beams was different, and collected the data of the fatigue test. Used hierarchical checking method, a second-order moment method to check the reliability of the beams, compared the results of fatigue reliability which calculated by two different checking methods. Analyzed and summarized the effect of size effect on fatigue reliability.

Considering the salient pole and high magnetic nonlinearity of the electromagnetic doubly salient (EMDS) DC generator, a 12/8 pole prototype EMDS generator is designed and calculated using a 2-D finite element method (FEM). The phenomenon is analyzed and that the phase voltage wave changes between 120° and 180°. The influence of the exciting current and armature reaction on the DC voltage ripple of the generator is discussed in detail, and the nonlinear rules are gained that DC voltage ripple changes accordingly. The theoretical analysis is verified by the simulation and experimental results. The results are helpful for the optimal design of the generator and the optimal control of exciting-winding. We conclude that the filter-capacitance of the rectifier can be designed.