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The catalytic performance of metal oxide surface mainly depends on its atomic surface structure, which usually changes under various treatment conditions and during catalytic reactions. Therefore, it is quite important to acquire the atomic geometries of the surfaces under different treatments for further understanding the catalytic mechanisms in the surfaces with complicated reconstructions. Here, we report the investigation on the evolution of surface geometries of the Ar+-ion-sputtered anatase TiO2(001) films followed by heating treatments at various temperatures, characterized using variable-temperature scanning tunneling microscopy. Our experimental results reveal the different surface morphologies at different heating temperatures. During the heating treatment, the migrations of O atoms from the bulk to the surface of TiO2(001) play an important role in the reoxidation of the Ti2+ and Ti3+ states for the formation of (1×4) reconstruction. The atomic-resolution images of the ridges show asymmetric features, which well support the fully oxidized structural model of the reconstructed TiO2(001)-(1×4) surface. [ABSTRACT FROM AUTHOR]

This study was conducted to characterize the intracranial pressure response to non-penetrating ballistic impact using a "scalp-skull-brain" pig physical head model and live pigs. Forty-eight ballistic tests targeting the physical head model and anesthetized pigs protected by aramid plates were conducted with standard 9 mm bullets at low (279-297 m/s), moderate (350-372 m/s), and high (409-436 m/s) velocities. Intracranial pressure responses were recorded with pressure sensors embedded in similar brain locations in the physical head model and the anesthetized pigs. Three parameters of intracranial pressure were determined from the measured data: intracranial maximum pressure (Pmax), intracranial maximum pressure impulse (PImax), and the duration of the first positive phase (PPD). The intracranial pressure waves exhibited blast-like characteristics for both the physical model and l live pigs. Of all three parameters, Pmax is most sensitive to impact velocity, with means of 126 kPa (219 kPa), 178 kPa (474 kPa), and 241 kPa (751 kPa) for the physical model (live pigs) for low, moderate, and high impact velocities, respectively. The mean PPD becomes increasingly short as the impact velocity increases, whereas PImax shows the opposite trend. Although the pressure parameters of the physical model were much lower than those of the live pigs, good correlations between the physical model and the live pigs for the three pressure parameters, especially Pmax, were found using linear regression. This investigation suggests that Pmax is a preferred parameter for predicting the severity of the brain injury resulting from behind armor blunt trauma (BABT).

Electrospun nanofiber membranes (ENMs) of polyvinylidene fluoride which is known as solid phase extraction materials were fabricated through electrospinning technology. Different electrospinning conditions including polymer content, spinning voltage and flow rate were investigated. The optimal operation conditions for electrospun process were set at 12% of PVDF mass fraction, 12 kV of spinning voltage, 0.5 mL h−1 of flow rate, 15 cm of receiving distance, 22 °C of spinning temperature and 45% of environmental humidity. The self-made ENMs were introduced into a combined method of radial electric focusing solid phase extraction enrichment, ultrasonic elution, UV-Vis detection and PLS calculation for determining benzoic acid, phthalic acid and p-toluene sulfonic acid in aqueous samples simultaneously. The calculation results of unknown sample show that the concentrations of benzoic acid, phthalic acid and p-toluene sulfonic acid were 4.416 mg L−1, 4.976 mg L−1 and 5.27 mg L−1, respectively. The relative standard deviation values of each component are all less than 2% with a relative recovery of 84–119%. The ENMs illustrate their fascinating application prospects in determining trace complex materials in aqueous samples. [ABSTRACT FROM AUTHOR]