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For metal-intermetallic laminated composites, various types of defects often occur during the preparation process. This paper studied the evolution and formation mechanism of defects, such as pores, tunnel cracks, and delamination cracks in Ti-Al3Ti laminated composites prepared by vacuum hot-pressing method. Moreover, quasi-static and dynamic compression tests were performed to study the effects of pores and delamination cracks on the compression properties of the composites. The results showed that for Ti-Al3Ti laminated composites prepared at 710 ℃, their Al3Ti layers exhibit a porous structure, and the porosity of Al3Ti layers firstly decreases and then increases under the combined action of press, the self-propagating reaction and Al3Ti grain coarsening. The tunnel cracks in Ti-Al3Ti laminated composites are resulted by tensile residual stresses and the inherent brittleness of Al3Ti. For Ti-Al3Ti laminated composites prepared at 680 °C, the formation of delamination cracks is mainly related to the diffuse reaction of Ti/Al atoms and the Kirkendall effect, and the numbers of delamination cracks increase with the increasing of sintering time. Moreover, the pores and delamination cracks greatly deteriorate the compression properties of Ti-Al3Ti laminated composites. Crack-free and dense Ti-Al3Ti laminated composites exhibit the highest compression properties.

Early degradation of cast-in-situ concrete induced by multiple internal–external sulfate combined attacks significantly affects the development of concrete strength. An experimental study regarding the effects of Ca2+ on the early degradation of cast-in-situ mortars subjected to internal–external sulfate and magnesium combined attacks is investigated in this paper. In particular, a specific method for accurately simulating the degradation of cast-in-situ structures was proposed in this experiment. Physical properties (including weight, size changes, and porosity), mechanical properties (including flexural strength and compressive strength), sulfate concentration, and microstructural properties were monitored during 28 days of immersion. The results show that an internal sulfate and magnesium combined attack (ISA-IMA) obviously retards the development of early strength and accelerates the degradation induced by external sulfate attack (ESA). The diffusion path of sulfate ions from outside is blocked by flake-shaped magnesium hydrates, delaying the penetration of external sulfate attacks. However, it is far from neutralizing the strength loss induced by an internal magnesium attack (IMA) at an early age. Premixed excessive Ca2+ would improve the strength development and pore structure of concrete or mortar, enhancing durability against corrosive conditions.

Early degradation of cast-in-situ concrete induced by multiple internal-external sulfate combined attacks significantly affects the development of concrete strength. An experimental study regarding the effects of Ca

Despite recent breakthroughs in deep learning methods for image lighting enhancement, they are inferior when applied to portraits because 3D facial information is ignored in their models. To address this, we present a novel deep learning framework for portrait lighting enhancement based on 3D facial guidance. Our framework consists of two stages. In the first stage, corrected lighting parameters are predicted by a network from the input bad lighting image, with the assistance of a 3D morphable model and a differentiable renderer. Given the predicted lighting parameter, the differentiable renderer renders a face image with corrected shading and texture, which serves as the 3D guidance for learning image lighting enhancement in the second stage. To better exploit the long-range correlations between the input and the guidance, in the second stage, we design an image-to-image translation network with a novel transformer architecture, which automatically produces a lighting-enhanced result. Experimental results on the FFHQ dataset and in-the-wild images show that the proposed method outperforms state-of-the-art methods in terms of both quantitative metrics and visual quality. We will publish our dataset along with more results on https://cassiepython.github.io/egsr/index.html., Comment: {\dag} for equal conribution. Accepted to CGF. Project page: https://cassiepython.github.io/egsr/index.html

The VenaTech convertible filter (VTCF) has been widely used as an inferior vena cava (IVC) filter to prevent fatal pulmonary embolism in patients. However, its hemodynamics that greatly affect the filter efficacy and IVC patency are still unclear. This paper uses computational fluid dynamics with the Carreau model to simulate the non-Newtonian blood flows around the VTCF respectively deployed in the normal, reverse and three converted states in an IVC model. The results show that the prothrombotic stagnation zones are observed downstream from the normal, reverse and small open VTCFs, with the streamwise length is nearly eight times the IVC diameter. The no-slip boundary conditions of the thin-wire VTCF arms lead to the "viscous block" effect. The viscous block accelerates the blood flow by 5-15% inside the IVC and enhances the filter wall shear stress up to nearly 20 times that of the IVC only, which contributes to clot capture and thrombus lysis. The relative flow resistance is defined to evaluate the filter-induced resistance on the IVC blood flow that can be regarded as an index of IVC patency with the filter deployment. The flow resistance of the normal VTCF deployment increases dramatically by more than 60% compared with that of the IVC only and is a little higher (6%) than that of the reverse case. As the VTCF converts to a fully open configuration, the flow resistance gradually decreases to that of no filter. This work shows that even very thin VTCF arms can result in the viscous block effect and may cause significant hemodynamic impacts on clot capture, potential thrombosis and flow impedance inside the IVC. The present study also shows that CFD is a valuable and feasible in silico tool for analyzing the IVC filter hemodynamics to complement in vivo clinical and in vitro experimental studies.

The first-principles tensile simulation was carried out to investigate the Al(111)/Al3Ti(112) interface tensile properties and failure mechanism through the calculated tensile stress, deformation energy, bond length, bond angle, lattice constant, and charge distribution. Results showed that the maximum tensile strength of the Al(111)/Al3Ti(112) interface is 14.38 GPa and the deformation energy is mainly absorbed by the interface and Al side. When the tensile strain exceeds 25%, partial Al–Ti and Al–Al chemical bonds at the interface break and the tensile model is destroyed. As a result of the increasing tensile strain, the lattice constant b (the side length along the [010] direction) decreases continuously and rapidly, and electron holes appear in a large area at the interface and sub-interface, which severely weakens the interaction between atoms. These phenomena indicate that the Al/Al3Ti interface and sub-interface are weak links and fail easily.

In order to theoretically clarify the interface properties of the Ti/Al3Ti laminated composites, based on the interface orientation relationship characterized by electron back scattering diffraction technology, the adhesion work, electronic structure and bonding properties of the Ti/Al3Ti interfaces were calculated by first-principles calculations. Four Ti(0 0 0 1)/Al3Ti(0 0 1) models with different terminations (Al-terminated and Al + Ti-terminated) and different stacking sites (top-sites, and center-sites) were investigated. Results showed that the Al3Ti(0 0 1) surface energies of Al + Ti-termination (1.96–2.53 J/m2) are higher than that of Al -termination (1.87–1.29 J/m2), which indicates that the Al-terminated surface is more stable; Al-termination-center-sited model has the largest adhesion work (3.202 J/m2) and the strongest charge interaction, which is the best stability among the four Ti/Al3Ti interfaces; The calculated PDOS suggests that the interfacial bond of Al-termination-center-sited interface is the Al - Ti covalent bond, it is the result of the hybridization between the Ti-3d and Al-3p, and the interior atoms in A13Ti (0 0 1) slab have more covalent features than the interfacial atoms.

In present work, two Ti-Al3Ti laminated composites containing different fractions of Al were fabricated by vacuum hot pressing sintering with the same process but different reaction time at 660 °C. Electron back scattering diffraction (EBSD) technology was used to characterize the microstructure evolution of Al3Ti layer at Ti/Al3Ti interface and Al3Ti/Al interface of the two specimens respectively, including the mean grain size, the distribution of grain boundaries, the crystallographic orientation distribution and the dislocation density. The results showed that: for the mean grain size of Al3Ti, a decreased tendency was occurred at Ti/Al3Ti interface with the reaction time prolonging, while at Al/Al3Ti interface, it was an increased tendency; for the fraction of low angle grain boundary, at Ti/Al3Ti interface, it decreased with a longer reaction time, while at Al/Al3Ti it increased, which resulted from continuous dynamic recrystallization and discontinuous dynamic recrystallization mechanism, respectively. The Al3Ti grains close to Ti exhibited the (100)〈001〉 and (110)〈001〉 textures but no texture existed at Al3Ti close to Al. Meanwhile, the texture strength decreased due to the effect of recrystallization.

In order to further improve the mechanical properties of Ti-Al3Ti laminated composites, the endothermic semisolid reaction was used to fabricate Ti-Al3Ti-Al laminated composites, and the quasi-static compressive test, dynamic compressive test, and the ballistic penetration test were conducted on these composites. The results showed that the compressive strength and failure strain of Ti-Al3Ti-Al laminated composites prepared at 660°C are 1432 MPa and 35%, respectively. The dynamic response of these composites has obvious strain rate effect, and the crack grows in the shape of “Z.” The V50 of Ti-Al3Ti-Al targets is 509 m s−1. To sum up, Ti-Al3Ti-Al laminated composites have better mechanical properties and anti-penetration properties compared to Ti-Al3Ti laminated composites.

In this paper, we describe a single port probe for miniaturized imaging system. The probe antennas are optimized using computer simulation technology (CST) Microwave Studio (MWS) to achieve a good sensitivity to permittivity over a bandwidth of 15–20GHz. Comparing with others, our design can be applied to the near field imaging and the resolution becomes higher than the far-field imaging.

This paper presents a multi-band fractal antenna designed for RF energy harvesting. The antenna is based on a general cross-dipole antenna. By adding iterated slot on each pole, a widely multi-band performance is achieved. Size and iteration time of the antenna are optimized via simulation on HFSS, and as a result the antenna covers most of the common RF resources such as 3G, 4G and WLAN in 2.4 GHz and 5.8 GHz. A derivative version of the antenna is developed by surround the original antenna with a ring structure for a better 900 MHz performance. Besides the multi-band characteristic, the antenna is also of compactness and artistic appearance.