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Face recognition is a prevalent identity verification method, but it requires a liveness detection system to guard against face fraud from printed images and mobile phone photographs. It is challenging to guarantee low complexity and high accuracy of the face anti-spoofing model applied on the Android development board at the same time in existing research. On the Android development board, we construct a liveness detection system that is resistant to attacks from printed images and photographs of electronic devices such as tablets. In conjunction with the actual circumstance, we create a lightweight liveness detection algorithm based on near-infrared images. We utilize MTCNN to clip the near-infrared images in order to preserve the facial portions and reduce the calculated cost. After applying Gamma correction to weaken the impact of illumination on the faces, the facial images are subsequently incorporated into the enhanced ShuffleNet V2 model based on the MBConv and squeeze-excitation (SE) modules for secondary classification. We evaluate the performance of the enhanced model on the CBSR NIR Face Dataset, CASIA NIR-VIS 2.0 Face Database and Oulu-CASIA, achieving 98.50%, 99.87% and 100% accuracy, which is superior to the performance of the original ShuffleNet V2 model and state-of-the-art methods. Our model's FLOPs and Params are 0.28 G and 2.17 M, respectively. Meanwhile, the liveness detection system based on Android has an exceptionally high level of security performance [ABSTRACT FROM AUTHOR]

Bidirectional reinforced embankment (BRE) technology, pile supporting in vertical and geosynthetic reinforcement in horizontal, has been widely adopted in engineering practice to control total and/or differential settlement. In design, the load distribution of BRE is essential for determining pile size (i.e., diameter and length), pile spacing, pile cap details (if any), and properties of geosynthetic reinforcement, et al. Several methods have been proposed in previous studies to investigate the load bearing mechanism in the BRE platform. However, resistance of foundation soil is typically neglected, which implies that the load on piles would be overestimated if the resistance of foundation soil is neglected or over weakened. The reason for this overestimation is that larger geosynthetic deflection would be expected without the reaction of foundation soil, which would cause a more significant soil arching and thus more load would be transferred to piles. To minimize this overestimation, a method for analyzing load transfer mechanism in the BRE was proposed, considering the subsoil resistance as well as the existence of neutral plane (i.e., zero skin friction). An equal settlement was assumed for soils at the embankment bottom and the foundation top. The iteration process was adopted to solve equations to determine the load shared by piles and soils. In derivation, the soil arch height in the embankment was calculated instead of being assumed in existing methods. A flow chart was developed to solve equations of the proposed method and two case histories from literatures were used to compose the rationality verification. Compared with the field measurement and numerical calculation, this study can be more effective in calculating loads shared by piles and soils in the BRE for the working condition with better pile end bearing stratum. [ABSTRACT FROM AUTHOR]

This paper presents a case study of investigating the cause of ground sliding during tunneling in the mountain with sloping and stratified stratum, which is implemented by field investigation and numerical analysis. Especially, the strength reduction finite element method is adopted to numerically investigate the influence of surrounding rocks stability from heavy rainfall permeating into ground. Both the field and numerical investigations demonstrate that the ground sliding during tunneling in the sloping and stratified stratum is induced by heavy rainfall permeating into the mountain ground with sloping and stratified stratum, in which heavy rainfall is observed before ground sliding and the instability of mountain slope is reduced with the gradually decreased rainfall. Moreover, the numerical analysis demonstrates that the plastic zones of surrounding rocks in the case of tunneling work implemented later than heavy rainfall are less developed than those in the case of tunneling work implemented earlier than heavy rainfall, which also implies the heavy rainfall permeating into the mountain ground has significant influence on the ground sliding during tunneling in the sloping and stratified stratum. [ABSTRACT FROM AUTHOR]

In this work, based on the nonlinear Schrödinger equation with quintic higher-order nonlinearity and higher-order dispersion effects, we investigate the dynamics of bright soliton in power-law nonlinear medium with quintic-order nonlinearity. Via the F-expansion method, we derived the typical bright soliton solution of such system and show the system's power-law characteristics of the derived bright soliton evolution graphically. Meanwhile, we show the stability of the bright soliton for the power-law system under the system's appropriate practical parametric setting. The theoretical results derived in this work can be used to guide the experimental observation of the dynamic behavior of solitons in higher-order nonlinear power-law systems with higher-order dispersion. [ABSTRACT FROM AUTHOR]

There were several damaging behaviors observed in a highway tunnel under construction, caused by the large deformation of rock mass. For this reason, a laboratory test to analyse the mineral composition was implemented, which aims to figure out the cause of the large deformation when tunneling in carbonaceous slate stratum. The laboratory test shows the reactivity of clay minerals with water is one of the important reasons lead to large deformation. Especially, field test was adopted to evaluate the structural stability and safety, affected by large deformation resulted from carbonaceous slate stratum. Displacement of primary lining, internal force of steel arch, pressure between primary lining with rock mass, internal force of secondary lining and seepage pressure of tunnel bottom were monitored and presented during tunneling. The results demonstrate that the mechanical response and stress state of the tunnel reflect the influence of the large deformation. For primary lining, large and asymmetrical deformation, which may result in the failure of steel arch, shows high risk in safety. Moreover, according to the calculated criterion of bearing capacity, once the secondary lining starts to bear pressure from rock mass, unsafety and minor safety reservation of the secondary lining were obtained in two regions of this structure. The result in this paper can provide valuable guidance for the subsequent construction and the similar engineering projects located in this area. [ABSTRACT FROM AUTHOR]

The cracks caused by fracture of concrete lining have adverse impacts on the tunnel structure, considering the influences of serviceability and durability. In this paper, a particular case study of a newly built tunnel structure is presented for a certain amount of longitudinal cracks, focusing on the inducement of cracking and effect of concrete fracture. An integrated field investigation is implemented to characterize the spatial distribution of longitudinal cracks and detailed site situations, and the temperature difference of concrete within the lining is as inducement according to a series of reliable experiments. To further understanding of the lining structure performance influenced by fracture behaviors, two groups of numerical models based on finite element software are simulated for reinforced concrete and concrete cross sections, respectively. Among the numerical models, a simplified crack model is applied for damaged lining structure, considering the realistic width and depth of cracks. Ultimately, different safety factors are adopted not only for verifying the stability of cracks but also for getting the differences of structural safety under maintenance work. Situations of crack are in accordance with the real conditions in situ, besides the maintenance work is proved as essential and effective methods in this damaged tunnel. [ABSTRACT FROM AUTHOR]

Pure titanium (Ti) TA1 fibers/wires with 0.08 and 0.15 mm diameters were processed by a novel method that combined press forming, vacuum sintering (≥10 Pa), and heat treatment to fabricate entangled Ti wire materials (ETWMs). The ETWMs exhibited a total porosity ranging from 44.2 ± 0.1 to 81.2 ± 0.1% and an open porosity ranging from 43.5 ± 0.1 to 80.9 ± 0.1%. The processing parameters of fiber diameter, formation pressure, sintering temperature, and sintering time were applied to examine porous ETWM morphology, porosity, pore size, and mechanical properties. The importance of primary factors controlling porous structure and porosity in ETWMs were found to be fiber/wire diameter > formation pressure > sintering temperature > sintering time. Furthermore, Ti fiber diameter was shown to directly impact pore size. High formation pressure resulted in a fine, uniform porous structure with low porosity. Sintering at high temperature for long-time periods promoted sintering point formation, resulting in neck coarsening. This effect contributed to the characteristic mechanical properties observed in these ETWMs. If the sintering effect is considered in isolation, ETWMs fabricated with 0.08 mm diameter Ti fibers/wires and sintered at 1300 °C for 90 min achieved smaller, more uniform porous structures that further exhibited improved connections among fibers/wires and excellent mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract: A new non-Euclidean continuum damage model is proposed to investigate the zonal disintegration phenomenon of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition as well as the total elastic stress field distributions. The elastic stress fields of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition are obtained. If the elastic stresses of the surrounding rocks satisfy the strength criterion of the deep rock masses, the number, size and location of fractured and nonfractured zones are determined. The effect of physico-mechanical parameters of the surrounding rocks on the zonal disintegration phenomenon is studied and numerical computation is carried out. It is found from numerical results that the number, size and location of fractured and non-fractured zones are sensitive to the physico-mechanical parameters of the surrounding rocks. [Copyright &y& Elsevier]

The mechanical behaviors of deep rock mass are different from those of shallow rock mass. Through cases of Jinping II Hydropower Station, the special phenomenon of zonal disintegration in the surrounding rock mass around the diversion tunnels, is analyzed. On the basis of fracture mechanics, a new strength criterion for deep rock mass is derived. The new nonlinear strength criterion that is relative to the rock mass rating classification can be applied to the study of the tensile failure of deep rock mass. Subsequently, zonal disintegration model is established, and the radius of fractured zone and none-fractured zone of deep surrounding rock mass around cylindrical tunnel are obtained, their exact positions and the evolution law of zonal disintegration of surrounding rock mass is determined. To validate the present model, comparison between calculation results and the experiment observation on facture and failure around underground openings is carried out. It is found that the numerical simulation result is in good agreement with the experimental one on failure modes around the hole. Through sensitivity analysis, the effects of stress condition, cohesion and the angle of internal friction on the phenomenon of zonal disintegration are determined. Finally, the present model is adopted in the analysis of the zonal disintegration in the surrounding rock mass around the diversion tunnels in Jinping II Hydropower Station. Meanwhile, the magnitude and distributions of fractured zones are determined by numerical simulation. [ABSTRACT FROM AUTHOR]

Comparison in the heart rate, oral temperature and lymphocyte DNA damage during heat stress was made in pilots with negative antibodies to heat stress proteins (HSPs) and those with positive antibodies in the man-made climate room with Western blot and comet assay. Our results showed that the increase in oral temperature, heart rate and lymphocyte DNA damage in pilots with the positive antibodies to HSPs were higher than those in pilots with the negative antibodies during heat stress. These results indicated that the presence of autoantibodies in plasma of pilots might reflect heat damage and high sensitivity to heat. [ABSTRACT FROM AUTHOR]

The NiO/NiCo2O4 mixtures with unique yolk-shell structure were synthesized by a simple hydrothermal route and subsequent thermal treatment. The elemental distribution, composition, and microstructure of the samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and scanning electron microscope (SEM), respectively. The microwave absorption property was investigated by using vector network analysis (VNA). The results indicated that the excellent electromagnetic wave absorption property of the NiO/NiCo2O4 mixtures was achieved due to the unique yolk-shell structure. In detail, the maximum reflection loss (RL) value of the sample reached up to − 37.0 dB at 12.2 GHz and the absorption bandwidth with RL below − 10 dB was 4.0 GHz with a 2.0-mm-thick absorber. In addition, the NiO/NiCo2O4 mixtures prepared at high temperature, exhibited excellent thermal stability. Possible mechanisms were investigated for improving the microwave absorption properties of the samples. [ABSTRACT FROM AUTHOR]

Silicon nitride was firstly used as anticorrosive pigment in organic coatings. An effective strategy by combining inorganic fillers and organosilanes was used to enhance the dispersibility of silicon nitride in epoxy resin. The formed nanocomposites were applied to protect Q235 carbon steel from corrosion. The anticorrosive performance of modified silicon nitride with silane (KH-570) was investigated by electrochemical impedance spectroscopy (EIS), water absorption and pull-off adhesion methods. With the increase of immersion time, the corrosion resistance as well as adhesion strength of epoxy resin coating and unmodified silicon nitride coating decreased significantly. However, for the modified silicon nitride coating, the corrosion resistance and adhesion strength still maintained 5.7×1010 Ω cm2 and 7.6 MPa after 2400-h and 1200-h immersion, respectively. The excellent corrosion resistance performance could be attributed to the chemical interactions between KH-570 functional groups and silicon nitride powders, which mainly came from the easy formation of Si-O-Si bonds. Furthermore, the modified silicon nitride coating formed a strong barrier to corrosive electrolyte due to the hydrophobic of modified silicon nitride powder and increased bonds. [ABSTRACT FROM AUTHOR]