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A method was established for the determination of the elemental composition in plant samples using the characteristic argon fluorescence peak in the air as a normalization standard via low power total reflection X-ray fluorescence (LP-TXRF) spectrometry using polychromatic X-ray excitation. The source of the Ar peak was demonstrated both theoretically and experimentally. According to the theoretical study, the characteristic Ar peak mainly originates from the optical path of the incident and reflected X-rays and the standing wave field formed by the incident and reflected X-rays. Additionally, the experiments confirmed the main contribution of the standing wave fields formed by the incident and reflected X-rays to the Ar characteristic peaks, and the influence of reflector type and sample deposition amount on the Ar characteristic peaks was excluded. Three different plant certified reference materials (CRMs) were employed to evaluate the effectiveness of the proposed methodology for multi-elemental quantitative analysis. The results showed that the Ar-peak normalization method resulted in comparable accuracy and precision compared with the conventional internal standard method, and a long-term stability check under the same conditions showed the good stability of the argon peak.

The lateral pressure generated by liquefied soil on pile is a critical parameter in the analysis of soil-pile interaction in liquefaction-susceptible sites. Previous studies have shown that liquefied sand behaves like a non-Newton fluid, and its effect on piles has rate-dependent properties. In this study, a simplified pseudo-static method for liquefiable soil-pile interaction analysis is proposed by treating the liquefied soil as a thixotropic fluid, which considers the rate-dependent behavior. The viscous shear force generated by the relative movement between the viscous fluid (whose viscosity coefficient varies with excess pore pressure and shear strain rate) and the pile was assumed to be the lateral load on the pile. The results from the simplified analysis show that the distribution of bending moment is in good agreement with experiments data. Besides, the effects of various parameters, including relative density, thickness ratio of non-liquefiable layer to liquefiable layer, and frequency of input ground motion, on the pile-soil rate-dependent interaction were discussed in detail.

A glass-based IPD band-pass chip filter for 5G N77 application is presented in this paper. This filter is composed of five shunt LC resonators. The low loss passband performance is realized by two LC resonators connected in shunt near the input and output terminals. The high rejection property for the stopband is realized by three LC resonators connected in series on the main branch of this filter. This filter is successfully manufactured with a commercial glass IPD process. Its chip size is $\mathbf{1.6\times 0.8{mm}^{2}}$ . The measurement results show that, the working frequency band of this filter is 3.2-4.0GHz, the maximum passband loss is only 2.0dB, and the stopband rejection is higher than 30dB at the designed zero-point frequencies.

Defect-mediated Z-scheme BiO2-x/Bi2O2.75 heterojunction photocatalysts without electron mediator was prepared via a simple low-temperature hydrothermal method. DFT proved that the existence of oxygen vacancies would affect the geometric and electronic structure of BiO2-x and Bi2O2.75, which played an indispensable role in promoting exciton dissociation. BiO2-x/Bi2O2.75 exhibited a higher redox ability compared with the pure BiO2-x due to the Z-scheme photocatalytic mechanism, which could be ascribed to the formation of the build-in electric field induced by Bi and O defects. The as-synthesized photocatalysts exhibited excellent photocatalytic activity over the full solar spectrum from UV to NIR light due to the LSPR effect of oxygen vacancies, indicating its effective utilization of solar energy. The degradation rates of RhB over the optimal BiO2-x/Bi2O2.75 were 8.49, 10.22 and 3.24 times higher than that of the pure BiO2-x under visible light, simulated sunlight and NIR light irradiation, respectively. The excellent photocatalytic activity was ascribed to the synergistic effects of the LSPR effect of oxygen vacancies and the Z-scheme interfacial heterojunction. It was believed that this work provided a new idea to design high active and full solar spectrum-driven photocatalysts for energy conversion and environmental remediation.

Highly active Zn2SnO4N photocatalysts were successfully prepared by the one-step microwave-assisted solvothermal method. N heteroatoms were introduced into Zn2SnO4 by occupying the interstitial sites, inducing the formation of the build-in polarization electric field and the impurity level which was advantageous to promote the separation and the migration of photoinduced electron-hole pairs. As a result, the as-prepared Zn2SnO4N exhibited improved the photoelectrochemical properties and the photodegradation rate of RhB over Zn2SnO4N had been demonstrated to increase 3.3 times compared to that of pure Zn2SnO4. Under the effect of the built-in electric field, the impurity level served as a springboard for electron transition rather than a recombination center, which caused the enhancing photocatalytic performance. The finding may provide a new insight into understanding the mechanism of doping modification.

The g-C3N4/{010} facets BiVO4 interface Z-scheme photocatalysts is fabricated by ultrasonic dispersion method. The density functional theory (DFT) shows that the differences of the energy levels in the conduction bands and the valence bands between the {010} and {110} facets of BiVO4 is about 0.37 and 0.31 V (vs. NHE, pH = 7), respectively. Therefore, the co-exposed {010} and {110} facets of BiVO4 can form surface heterojunction, which promotes the {010} facets of BiVO4 with negative charge. The zeta potential indicates that layered g-C3N4 with positive charge. The Raman, FT-IR and XPS analysis demonstrates that the layered g-C3N4 is anchored on the {010} facets of BiVO4 through strong interface electrostatic interaction, which leads to form a built-in electric field at the contact interface. Under the built-in electric field driving, photogenerated electrons in the CB of {010} facets of BiVO4 rapidly recombines with the holes in the VB of g-C3N4 to form the interface Z-scheme heterostructure. That is, BiVO4 surface heterojunction ultimately induces the formation of interface Z-scheme heterostructure. The interface Z-scheme heterostructure not only facilitates the space separation of the photogenerated carriers, but also accumulates electrons in the more negative potentiated CB of g-C3N4 and holes in the more positive VB of {110} facets of BiVO4. Consequently, by means of the I-t, LSV and EIS measurements, the g-C3N4/{010} facets of BiVO4 interface Z-scheme photocatalysts presents extraordinary photoelectrochemical performance. More importantly, the degradation rate of g-C3N4/{010} facets of BiVO4 interface Z-scheme photocatalysts can reach the highest 88.3% within 30 min under visible light irradiation, and the mineralization ability (96.03%) is about 2.24 and 3.32 times as high as that of BiVO4 (42.83%) and g-C3N4 (28.89%), respectively.

An energy-selective X-ray tube based on a magnetically controlled method is proposed here. An X-ray tube with two selective targets, modulated by a magnetic field, was developed for the X-ray fluorescence (XRF) analysis of multielement samples. The X-ray tube was small (20 cm length × 4 cm width) and had low power, being operated at 20 W (20 kV, 1 mA). It contained a thermionic cathode and two targets [copper (Cu) and chromium (Cr)] mounted on the anode. The electron beam was drifted by a modulated magnetic field to bombard either the Cu or Cr targets and so produce the required emission spectrum. Particle dynamics analysis software was used to simulate the particle tracking of the X-ray tube. The focal spot on the anode was successfully drifted, and a focal spot at 2 × 2.3 mm2 was obtained with a pinhole camera method. The XRF analysis of a standard sample (a mixture of Fe2O3 and CaCO3) was measured by a silicon drift detector. When the bombarding target was changed from Cu to Cr, the characteristic calcium (Ca) X-rays that were detected were twice as strong as those of iron (Fe), but they had a similar excitation efficiency. It was demonstrated that this X-ray tube can provide fast exchangeable X-rays for XRF analysis by modulating the magnetic field intensity and can be further improved by optimizing the structure for alternative applications.

In order to improve the shielding performance of the underbody protective structure of military vehicles when subjected to explosive events, a multi-layer honeycomb sandwich structure is proposed. Full consideration of the computing response of the underbody protective structure under blast loading is a large-scale and strongly non-linear problem; a reasonably simplified finite element model is constructed in this paper. LS-DYNA software was employed to simulate blast loading by using the *LOAD_BLAST equation and to compute the dynamic responses of the vehicle; then, full-scale experiments were performed to validate the accuracy of the numerical simulation. The geometric dimensions and the shape parameters of the multi-layer honeycomb sandwich structure are selected as the design variables, thereby establishing a response surface and a mathematical optimization model by employing the design-of-experiments method. A Pareto spatial optimal set is obtained by applying a multi-objective genetic algorithm. Eventually, using the normal-boundary intersection algorithm an optimum design was obtained, which can apparently enhance the shielding performance of the underbody protective structure of military vehicles without increasing the mass.

Several barium plumbate (BaPbO3) solid samples, made from PbO and BaCO3 powder by chemistry liquid-phase coprecipitation, were investigated before and after γ-irradiation. The solid samples were ir...