Anisotropic Shock Response of 3,4-Dinitropyrazole Revealed by First-Principles Calculations.

DNP (3,4-dinitropyrazole) has attracted much interest due to its promising melting characteristics and high detonation performances, such as low melting point, high density, high detonation velocity, and low sensitivity. In this work, first-principles molecular dynamics (MD) simulations were performed to investigate the anisotropic shock response of DNP in conjunction with the multiscale shock technique (MSST). The initial decomposition mechanism was revealed through the evolution of the chemical reaction and product analysis.

Variation of Corrosion Characteristics and Tensile Performances of WE43 Alloy Under Marine Atmospheric Environment.

This study aims to examine the variation in corrosion characteristics and tensile properties of WE43 magnesium alloy in an actual marine atmospheric environment by means of outdoor exposure tests. The macroscopic corrosion morphology, microstructure, and tensile properties were analyzed. The results indicated that WE43 alloy will corrode rapidly during exposure under marine atmospheric environmental conditions, resulting in a loose and porous Mg(OH) layer on the surface.

Multi-Objective Robust Design Optimization for Crashworthiness Enhancement of Hybrid 2D Triaxially Braided Composite Tube Using Evolutionary Algorithms.

An innovative optimal design framework is developed aiming at enhancing the crashworthiness while ensuring the lightweight design of a hybrid two-dimensional triaxial braided composite (2DTBC) tube, drawing insights from the mesostructure of the composite material. To achieve these goals, we first compile the essential mechanical properties of the 2DTBC using a concentric cylinder model (CCM) and an analytical laminate model. Subsequently, a kriging surrogate model to elucidate the intricate relationship between design variables and macroscopic crashworthiness is developed and validated.

Effects of an LPSO Phase Induced by Zn Addition on the High-Temperature Properties of Mg-9Gd-2Nd-(1.5Zn)-0.5Zr Alloy.

In this study, we prepared Mg-9Gd-2Nd-0.5Zr, referred to as alloy I, and Mg-9Gd-2Nd-1.5Zn-0.

Accelerating the electron-transfer of nitrogen electro-fixation through assembling Fe nanoparticles into Fe nanochains.

Electrochemically synthesizing NH N is a facile and sustainable approach that involves multistep electron and proton transfer processes. Thus, consecutive electron and proton transfer is necessary. Here, a universal method with the assistance of magnetic stirring that can assemble Fe, Co, and Ni nanoparticles into nanochains is developed.

Flexible and Multifunctional Composites with Highly Strain Sensing and Impact Resistance Properties.

The development of smart protective clothing will help detect injuries from contact sports, traffic collisions, and other accidents. The combination of ecoflex, spacer fabric, and graphene-based aerogel provides a multifunctional composite. It shows a strain sensitivity of 17.

Thiol-ene Click Chemistry Synthesis of L-Cysteine-Grafted Graphene Oxide As a New Corrosion Inhibitor for Q235 Steel in Acidic Environment.

l-cysteine, as an eco-friendly and nontoxic corrosion inhibitor, was directly covalently linked to the carbon/carbon double bonds of the GO flakes by a thiol-ene click reaction to avoid decreasing the number of hydrophilic oxygen-containing polar functionalities. The corrosion inhibition performances of Cys-GO toward Q235 steel (QS) in diluted hydrochloric acid were studied by electrochemical methods. The corrosion was a charge transfer-controlled process, and Cys-GO manifested as a mixed-type corrosion inhibitor.

Dynamic Marine Atmospheric Corrosion Behavior of AZ91 Mg Alloy Sailing from Yellow Sea to Western Pacific Ocean.

In this work, the dynamic marine atmospheric corrosion behavior of AZ91 Mg alloy sailing from Yellow Sea to Western Pacific Ocean was studied. The corrosion rates were measured using the weight loss method. The microstructure, phase, and chemical composition of corroded samples were investigated by SEM, EDS, XRD, and XPS.

Investigation of temperature effects on wide steel box girder of suspension bridge based on long-term monitoring data.

The time-varying temperature distributions on bridge structures may remarkably change structural performance, which may result in differential strain/stress responses on structural members compared with the design conditions. Therefore, it is crucial to have a comprehensive understanding of temperature distributions and its effects on bridges. In this study, taking advantage of structural health monitoring technology, 1-year field monitoring data collected from a long-span suspension bridge were used to investigate the temperature distributions and their effects on the steel box girder.

Research on Coated Tool Life and Wear in Ta-2.5W Alloy Turning.

Due to its inherent high hardness, strength, and plasticity, tantalum-tungsten (Ta-W) alloy poses a considerable challenge in machining, resulting in pronounced tool wear, diminished tool lifespan, and suboptimal surface quality. This study undertook experiments utilizing uncoated carbide tools, TiAlN-coated carbide tools, and AlTiN-coated carbide tools for machining Ta-2.5W alloy.

Effect of Local Pressurization on Microstructure and Mechanical Properties of Aluminum Alloy Flywheel Housing with Complex Shape.

In this work, squeeze casting experiments of flywheel housing components with a large wall thickness difference and a complex shape were carried out with AlSi9Mg aluminum alloy. The defects, microstructures, and mechanical properties under different process parameters were investigated. Furthermore, the local pressurization process was applied to the thick-walled positions to force-feed the cast defects.

3D microscopy at the nanoscale reveals unexpected lattice rotations in deformed nickel.

In polycrystalline metals, plastic deformation is accompanied by lattice rotations resulting from dislocation glide. Following these rotations in three dimensions requires nondestructive methods that so far have been limited to grain sizes at the micrometer scale. We tracked the rotations of individual grains in nanograined nickel by using three-dimensional orientation mapping in a transmission electron microscope before and after in situ nanomechanical testing.

Effect of Zn Addition on the Microstructure, Mechanical Properties, and Fracture Behavior of As-Cast Mg-Gd-Y-Zr Alloys.

The microstructure and mechanical properties of semi-continuous casting Mg-Gd-Y-Zr magnesium alloys with different Zn contents were studied in this paper. The results showed that an increase in Zn content resulted in gradual refinement of the grains and a gradual increase in the volume fraction of the second phase. At a Zn content of 0.

Impact of Marine Atmospheric Corrosion on the Microstructure and Tensile Properties of 7075 High-Strength Aluminum Alloy.

This study aimed to investigate the impact of corrosion on the microstructure and tensile properties of 7075 high-strength alloy. It involved outdoor exposure tests in an actual marine atmospheric environment in Wanning, Hainan Province. The results showed that the 7075 alloy was corroded rapidly in the marine atmospheric environment, and corrosion pits and intergranular cracks were generated.

Unmanned Aerial Vehicle (UAV) Robot Microwave Imaging Based on Multi-Path Scattering Model.

Unmanned Aerial Vehicle (UAV) robot microwave imaging systems have attracted comprehensive attention. Compared with visible light and infrared imaging systems, microwave imaging is not susceptible to weather. Active microwave imaging systems have been realized in UAV robots.

Corrosion Behavior and Mechanical Performance of 7085 Aluminum Alloy in a Humid and Hot Marine Atmosphere.

This work analyzed changes in the corrosion morphology and mechanical performance of 7085 aluminum alloy after outdoor exposures for different times in a humid and hot marine atmospheric environment. After one month of exposure, a pronounced corrosion of the alloy was observed. The corrosion product was mainly Al(OH), and the corrosion features were mainly pitting corrosion and intergranular corrosion (IGC).

Thermal Decomposition Behavior of Polyimide Containing Flame Retardant SiO and Mg(OH).

The effects of flame retardant silica (SiO) and magnesium hydroxide (Mg(OH)) on the thermal decomposition process of polyimide (PI) are discussed in this paper. Firstly, the decomposition process of PI in a nitrogen and oxygen atmosphere was studied by thermogravimetric analysis and differential scanning calorimetry methods, and the kinetic parameters were calculated by the nonlinear fitting method. In an inert atmosphere, PI decomposition consists of a three-step endothermic reaction, whereas in an oxygen atmosphere, PI decomposition consists of two steps, in which the first step does not change, and the second step changes to a violent exothermic peak.

Microstructure analysis, tribological correlation properties and strengthening mechanism of graphene reinforced aluminum matrix composites.

In this paper, graphene reinforced aluminum matrix composites are successfully prepared by high-energy ball milling. The results show that no graphene agglomeration is found in the mixed powder. The complex composites prepared by high energy ball milling and powder metallurgy have approximately 4-5 layers of graphene and the thickness of single-layer graphene is approximately 0.

Recent Progress in Functionalized Coatings for Corrosion Protection of Magnesium Alloys-A Review.

Magnesium (Mg) and its alloys, which have good mechanical properties and damping capacities, are considered as potential candidate materials in the industrial field. Nevertheless, fast corrosion is the main obstacle that seriously hinders its wide applications. Surface modification is an available method to avoid the contact between corrosive media and Mg substrates, thus extending the service life of Mg-based materials.

Effect of Annealing on Microstructure and Corrosion Behavior of Interstitial Free Steel.

Interstitial free steels with various grain sizes and textures were prepared by cold-rolling followed by an annealing process. The effect of grain size, crystallographic orientations and stored energy on corrosion behavior of interstitial free steel was investigated. It was found that the deformed microstructure and dislocation boundaries were consumed by recrystallizing grains during annealing.

Effect of Recrystallization Annealing on Corrosion Behavior of Ta-4%W Alloy.

The effect of recrystallization annealing on corrosion behavior of Ta-4%W alloy was studied. It is found that the deformed sample contains high dense dislocations and dislocation boundaries. During annealing, these dislocations and dislocation boundaries are replaced by recrystallizing grains until the alloy is fully recrystallized.

Double Quantum Image Encryption Based on Arnold Transform and Qubit Random Rotation.

Quantum image encryption offers major advantages over its classical counterpart in terms of key space, computational complexity, and so on. A novel double quantum image encryption approach based on quantum Arnold transform (QAT) and qubit random rotation is proposed in this paper, in which QAT is used to scramble pixel positions and the gray information is changed by utilizing random qubit rotation. Actually, the independent random qubit rotation operates once, respectively, in spatial and frequency domains with the help of quantum Fourier transform (QFT).