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In order to reduce the influence of the coupling characteristics between the aircraft and engine of hypersonic vehicle, an integrated aircraft-engine control method of hypersonic vehicle is studied in this paper. Firstly, the control-oriented aircraft-engine integrated mathematical model of the hypersonic vehicle is established. Then, by using the nonlinear dynamic inversion (NDI) and the incremental nonlinear dynamic inversion (INDI), the outer loop control algorithm with slow attitude change and the inner loop control algorithm with fast angular rate change are respectively designed. Moreover, based on the online ontology model including aircraft-engine coupling characteristics of the hypersonic vehicle, the coupling control scheme of flight posture and engine of the hypersonic vehicle is designed in the form of control linkage. Finally, the reference model, error control, online estimation and other modules are introduced into the NDI controller to ensure the flight quality and robustness requirements of the hypersonic vehicle. The simulation results show that the aircraft-engine coupling control scheme based on the NDI achieves the expected control performance.

To address the problem of hypersonic vehicle interception, taking the air-breathing hypersonic vehicle as the target of interception, this paper employs the concept of engagement geometry to theoretically provide the necessary conditions for the successful interception of hypersonic vehicles as well as constraints on the velocity-leading angle of hypersonic vehicle from the perspective of a small velocity ratio (the velocity of the interceptor is lower than that of the hypersonic vehicle) based on the interception posture. Then, it puts forward the mathematical expressions for the interception space of the interceptor for different maneuvering modes of the hypersonic vehicle, taking the true proportional guidance law as an example. Finally, by simulation experiments, it presents the interception space changing curves on the conditions of different velocity ratios and different maneuvering modes of hypersonic vehicles, and systematically analyses the conditions of intercepting hypersonic vehicles from a small velocity ratio perspective. This study can provide a fundamental theoretical basis for the mid-end guidance handover conditions and guidance law design for the subsequent interception of hypersonic vehicles.

Objective To study the vascularization of the collagen ⁃binding basic fibroblast growth factor (bFGF) ⁃ loaded collagen membranes in soft tissue repair in the hard palates of rats. Methods Ninety⁃six male 6⁃week⁃old Wi⁃ star rats were randomly divided into 4 groups, and 3⁃mm⁃diameter circular soft tissue defects were produced from the distal surface of the third molar to the mesial surface of the first molar in their hard palates. The defects were covered with a collagen⁃targeting bFGF/collagen membrane, a free bFGF/collagen membrane, a collagen membrane or no mem⁃ brane (control group). Every 6th rat was randomly sacrificed at 1, 2, 4 and 8 weeks in every group after surgery. Wound healing and the number of new blood vessels were measured by hematoxylin⁃eosin (HE) staining. Results The num⁃ bers of new blood vessels in the collagen⁃targeting bFGF/collagen membrane group were 8.94 ± 0.61, 17.39 ± 2.08 and 11.22 ± 1.66 at 1, 2 and 4 weeks after surgery, respectively, which were significantly greater than the values in the oth⁃ er groups (P 0.05). Conclusion Collagen⁃targeting bFGF/collagen membranes had a favorable effect on promoting an⁃ giogenesis during wound healing, and promoted wound healing.

The accumulation of waste tires has resulted in very urgent environmental problems. Pyrolysis has been regarded as a green eco-friendly technology to deal with waste tires, and it is vital to make use of the pyrolysis carbon. Herein, we propose a new way to utilize pyrolysis carbon, to prepare carbon nanotubes with the help of ferrocene. The optimal preparation processes were determined by optimizing the parameters including the solvent, temperature, time, etc. The results of scanning electron microscopy and transmission electron microscopy evidenced the successful formation of carbon nanotubes. Meanwhile, the Brunauer–Emmett–Teller (BET) method and N2-adsorption showed that the yielded carbon nanotubes featured a large surface area and abundant pore structure in comparison with the pyrolytic carbon. Finally, the as-prepared carbon nanotubes were applied as the supports for Pt-based catalysts for the dehydrogenation of methylcyclohexane to produce hydrogen. The results showed that the Pt/carbon-nanotubes catalyst exhibited the highest conversion of methylcyclohexane (28.6%), stability, and hydrogen evolution rate (336.9 mmol/gPt/min) compared to the resulting Pt/commercial-activated-carbon (13.6% and 160.2 mmol/gPt/min) and Pt/pyrolytic-carbon catalysts (0.19% and 2.23 mmol/gPt/min). [ABSTRACT FROM AUTHOR]

A novel Z-scheme ZnFe2O4/BiVO4 heterojunction photocatalyst was successfully synthesized using a convenient solvothermal method and applied in the visible light photocatalytic degradation of ciprofloxacin, which is a typical antibiotic contaminant in wastewater. The heterostructure of as-synthesized catalysts was confirmed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy characterizations. Compared with the single-phase counterparts, ZnFe2O4/BiVO4 demonstrated considerably enhanced photogenerated charge separation efficiencies because of the Z-scheme transfer mechanism of electrons between the composite photocatalysts. Consequently, the 30% ZnFe2O4/BiVO4 catalyst afforded a degradation rate of up to 97% of 20 mg/L ciprofloxacin under 30 min of visible light irradiation with a total organic carbon removal rate of 50%, which is an excellent activity compared with ever reported BiVO4-based catalysts. In addition, the liquid chromatography-mass spectrometry and quantitative structure-activity relationships model analyses demonstrated that the toxicity of the intermediates was lower than that of the parent ciprofloxacin. Moreover, the as-synthesized ZnFe2O4/BiVO4 heterojunctions were quite stable and could be reused at least four times. This study thus provides a promising Z-scheme heterojunction photocatalyst for the efficient removal and detoxication of antibiotic pollutants from wastewater. [ABSTRACT FROM AUTHOR]