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Taking potassium hexatitanate whisker (PTW) modified by silane coupling agent KH550, aluminium nitrate inorganic salt and tetraethyl orthosilicate and deionized water, respectively, as infrared sunscreen, aluminium source and raw materials forming the network structure of a composite xerogel, a series of structurally intact PTW-doped Al2O3–SiO2 composite xerogel thermal-insulating materials were prepared by the sol–gel method and dried under atmospheric pressure. The infrared spectral characteristics, infrared radiation transmittance, microstructures, morphology and thermal conductivity of different composite materials prepared have been determined by a Fourier transform infrared spectrometer, UV–visible–near-infrared spectrophotometer, X-ray diffractometer, scanning electron microscope and thermal conductivity tester. The results exhibit that when the Al to Si molar ratio is 1 : 9, the composite material with 5 wt% modified PTW shows the best infrared radiation blocking performance and the lowest thermal conductivity (0.0604 W m−1 K−1).

This study was designed to establish the composition of wound dressing based on poly(2‐hydroxyethylmethacrylate)‐chitosan (PHEM‐CS) hydrogels‐loaded cerium oxide nanoparticle (CeONPs) composites for cutaneous wound healing on nursing care of the chronic wound. The as‐synthesised PHEM‐CS/CeONPs hydrogels nanocomposites were characterised by using UV–visible spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and thermo gravimetric analysis. The influence of PHEM‐CS/CeONPs hydrogels nanocomposites on the gelation time, swelling ratio, in vitro degradation, and mechanical properties was investigated. The as‐prepared PHEM‐CS/CeONPs hydrogels nanocomposites dressing shows high antimicrobial activity against Staphylococcus aureus and Escherichia coli. Similar trends were observed for the treatment of biofilms where PHEM‐CS/CeONPs hydrogels nanocomposites displayed better efficiency. Furthermore, the biological properties of PHEM‐CS/CeONPs hydrogels nanocomposites had non‐toxic in cell viability and excellent cell adhesion behaviour. After 2 weeks, the wounds treated with the PHEM‐CS/CeONPs hydrogels nanocomposite wound dressing achieved a significant closure to 98.5 ± 4.95% compared with the PHEM‐CS hydrogels with nearly 71 ± 3.55% of wound closure. Hence, this study strongly supports the possibility of using this novel PHEM‐CS/CeONPs hydrogels nanocomposites wound dressing for efficient cutaneous wound healing on chronic wound infection and nursing care. [ABSTRACT FROM AUTHOR]

Zr-based bulk metallic glass is an amorphous alloy. In order to study the burr problem in the groove milling process of Zr-based bulk metallic glass, the milling force in the process is studied experimentally. Then the effect of milling parameters on the burr of Zr-based bulk metallic glass was studied, and the relationship between milling force and burr was analyzed. In order to further study the milling burr of amorphous alloy, under the same test parameters, the single crystal alloy material (nickel base single crystal superalloy DD5) and the traditional polycrystalline metal material (304 stainless steel) were selected for comparative test and analysis. The results show that Zr-based bulk metallic glass has good groove milling machinability. The test results provide some experimental basis for groove milling of Zr-based bulk metallic glass. [ABSTRACT FROM AUTHOR]

Summary: In this article, the prescribed performance control strategy is extended to multi‐input multi‐output nonstrict‐feedback nonlinear systems with asymmetric input saturation, and not only each element in tracking error vector converges to a prescribed small region within preassigned finite time, but also the converging mode during the preset time is prespecifiable and controllable explicitly. By blending the barrier function with novel speed function, a prescribed performance controller using command‐filtered‐based vector‐backstepping design framework is proposed to steer the tracking error vector for the first time, where the boundedness of filter errors is guaranteed by sufficiently small time constant and an error compensator is constructed to handle the effects of filter errors. To attenuate the adverse effects resulted from nondifferentiable input saturation, hyperbolic tangent function is utilized to estimate asymmetric saturation function such that the control input is designed as a new state variable with initial value of zero in augmented system. Nussbaum function is employed to overcome singularity problem caused by the differentiation of hyperbolic tangent function. At each step of backstepping design, the universal approximation property of neural network and the command filter system are utilized to approximate uncertain dynamics and to solve algebraic loop obstacle due to nonstrict‐feedback structure, respectively. Moreover, only one parameter needs to be updated online to cope with the lumped uncertain dynamics by virtual parameter technology, rendering a control strategy with low complexity computation. The validity of the presented controller is verified by theoretical analysis and two‐link robotic system. [ABSTRACT FROM AUTHOR]

In order to study the milling machinability of Zr-based bulk metallic glass, a comparative experimental study on the surface roughness of the milling groove bottom surface for Zr-based bulk metallic glass was carried out in this paper. Through different processing materials, milling tools with different coatings, milling tools with different geometric parameters, and different processing conditions, a large number of comparative tests were carried out on the surface roughness of the milling groove bottom surface for Zr-based bulk metallic glass. The surface roughness values of the milling groove bottom surface are compared, studied, and analyzed from many angles (surface roughness Sa, Sq, Sz, Ssk, and Sku). The test results show that Zr-based bulk metallic glass has good milling machinability. It can obtain a low surface roughness value through the processing conditions and methods used in the test. The research content of this paper provides experimental basis for groove milling of Zr-based bulk metallic glass. At the same time, it also provides a strong test basis for the manufacture of Zr-based bulk metallic glass parts. [ABSTRACT FROM AUTHOR]