Ethylene is a fundamental building block in the chemical industry and is widely used in plastics, synthetic fibers, and fine chemicals. Traditional ethylene production heavily relies on high-temperature steam cracking, a process characterized by high energy consumption and significant carbon emissions. Ethane dehydrogenation (EDH) has emerged as a promising alternative due to its lower energy consumption and fewer by-products. Based on the presence or absence of oxidants, EDH can be classified into direct dehydrogenation (DDH) and oxidative dehydrogenation (ODH). Recent advances in metal-based catalysts for EDH were systematically reviewed, with a focus on their structure-performance relationships, coke resistance mechanisms, and catalytic pathway optimization strategies. In DDH systems, Pt, PtSn, and PtZn catalysts achieve high activity and stability through confinement effects and alloy engineering. Cr-based and Mo-based transition metal catalysts benefit from dopant modification and support tuning, which significantly enhance their anti-sintering and regeneration capabilities. In ODH systems, the O?-assisted route operates via a lattice oxygen redox cycle, highlighting the importance of oxygen vacancy regulation and oxidation state stability. Meanwhile, the CO₂-assisted route not only enables carbon capture but also improves ethane conversion and coke resistance. Future development directions are discussed, including multi-oxidant co-catalytic systems, in situ structural characterization, and artificial intelligence-assisted catalyst design.

Tb-Dy-Fe alloys, with their exceptional magnetostrictive properties, have been widely applied in transdu-cers, actuators, sensors, and other smart devices. However, the relatively low electrical resistivity (60 μΩ·cm) of these alloys leads to severe eddy current losses under alternating magnetic fields, significantly hindering their application in high-frequency operating conditions. A systematic review was conducted on the regulatory mechanisms of different preparation techniques for the electrical resistivity and magnetostrictive properties of Tb-Dy-Fe alloys. The results indicate that powder bonding methods can increase the electrical resistivity by 4 to 10 orders of magnitude and reduce eddy current losses by 70% to 96%, albeit with some degradation in magnetostrictive performance. The alloying method can increase the resistivity to 100-160 μΩ·cm, while still maintaining the magnetostrictive properties well. The mechanical cutting method can effectively suppress the temperature rise during the operation of the device. Future research directions may focus on developing high thermal-stability binder systems, advancing particle surface modification technologies, and achieving synergistic optimization of composition, processing, and perfor-mance, thereby promoting the development of Tb-Dy-Fe alloys toward high resistivity and high performance.

CoCrFeNiTi high-entropy alloy exhibits unique properties in machining processes due to its high corrosion resistance, high hardness and good wear resistance. However, the presence of Ti atoms affects the machinability of the overall material to varying degrees. Therefore, molecular dynamics simulation was employed to investigate the cutting performance of CoCrFeNiTi high-entropy alloy by analyzing its surface morphology, cutting force and crystal structure under different cutting depths and cutting speeds. The results show that with the increase of cutting depth, the surface morphology of the material changes significantly and the plastic deformation capacity enhances. Increasing the cutting speed leads to a higher accumulation height of surface atoms and further intensifies the plastic deformation. Moreover, the increase of cutting depth destroys the face-centered cubic (FCC) crystal structure of the material, while the increase of cutting speed reduces the plastic deformation and promotes the atomic diffusion phenomenon. The main cutting force increases with the increase of cutting depth. Dislocation density, as a cutting indicator, exhibits significant differences under various cutting conditions. Dislocation accumulation and entanglement increase the deformation resistance of the material. The research results indicate that reasonable selection of cutting speed and depth can adjust the cutting behavior of the material to improve machining efficiency, which provides a theoretical basis for the cutting of CoCrFeNiTi high-entropy alloy.

Tungsten and its alloys require reliable connection with heterogeneous metals for extreme environmental applications such as nuclear fusion reactors. Hot isostatic pressing diffusion bonding has emerged as a key technology to address the challenge of joining tungsten with heterogeneous metals, owing to its advantages in promoting interfacial diffusion and densification under high pressure and high temperature. The research progress on hot isostatic pressing diffusion bonding of tungsten with copper alloys, steel and tantalum is systematically reviewed. The intermediate layers available for diffusion bonding of tungsten and heterogeneous metals are summarized. Additionally, existing problems and development trends of hot isostatic pressing technology in the field of diffusion bonding are discussed.

GH901 alloy turbine discs are high-temperature load-bearing components in aircraft engines, and their performance has an important influence on the overall performance of the engine. Therefore, the differences in microstructure and mechanical properties of different parts of GH901 alloy turbine disk were studied. After heat treatment of raw materials, alloy materials are obtained, and forged turbine disk forgings are obtained. Samples are taken from different parts for analysis of microstructure and high-temperature mechanical properties. The experimental results indicate that there is a significant gradient difference between the microstructure and high-temperature mechanical properties of GH901 alloy in different parts. During the manufacturing process of GH901 turbine disk forgings, the hub area experienced significant deformation and high temperatures, resulting in a tho-rough dynamic recrystallization process and uniform grain refinement. This process significantly improves the room temperature tensile strength and plasticity of the material, while the fracture surface exhibits typical dimple like characteristics. The structure of the spoke plate is between the hub and the wheel rim, and its performance is relatively balanced. Due to insufficient deformation, rapid heat dissipation, and inadequate recrystallization process, the wheel rim has formed obvious mixed and coarse crystal structures, resulting in a significant decrease in its tensile and durability properties, and the fracture surface exhibits brittle characteristics. Overall, although forging reduces the ultimate durability life of materials, it significantly improves the uniformity of performance between different parts, which is beneficial for enhancing the overall stability and reliability of turbine discs in practical service.

The effects of activation process, Ni-P alloy bath pH, current density, plating thickness and Ni content in Ni-P alloy bath on the appearance and properties of Ni-P alloy pre plating on Nd-Fe-B materials were studied, and the optimal process parameters were determined. The neodymium iron boron material after mechanical processing was selected. Firstly, a layer of nickel phosphorus alloy was pre plated under different process conditions, and then copper and nickel layers were electroplated on this basis. The morphology and thickness of the coating were analyzed by scanning electron microscope and X-ray analyzer. The corrosion resistance of the coating was evaluated by salt spray test, and the surface roughness of the coating was studied by roughometer. The optimal plating process parameters are as follows: activation with 2% sulfuric acid, bath pH of 9.5~10.5, current density of 0.25~0.35 A/dm², nickel content of 6~9 g/L, and coating thickness of more than 1.5 μ m. the salt spray test of the obtained coating can reach 96 h. In this process, nickel phosphorus alloy coating is used as the pre coating of NdFeB material, which significantly improves the overall corrosion resistance of the coating on the premise of maintaining the structure of the outer coating, and provides a reliable guarantee for the application of NdFeB material in harsh environment.

This study addresses the issues of high energy consumption and low efficiency in traditional niobium diboride (NbB₂) preparation processes. Innovatively adopting a molten salt-assisted synthesis strategy, we successfully prepared structurally tunable NbB₂ materials using Nb₂O₅ and amorphous boron as precursors at 1000 ℃ under an argon atmosphere through three molten salt systems: LiCl-NaCl, LiCl-KCl, and NaCl-KCl. The crystal structure and micromorphology of the products were systematically characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). Furthermore, the thermal stability, optical properties, and superconducting characteristics of the materials were comprehensively investigated using thermogravimetry-differential scanning calorimetry (TG-DSC), ultraviolet-visible-near infrared spectrophotometry (UV-Vis-NIR), and a physical property measurement system (PPMS). The results indicate that the three molten salt systems can regulate the morphology, size and crystallinity of NbB₂: KCl reduces the particle size, while NaCl promotes agglomeration and enhances crystallinity. The sample obtained from LiCl-NaCl exhibits hygroscopicity, and the LiCl-containing systems possess stronger light absorption. The superconducting performance of NbB₂ is flux-dependent; the increase of KCl content elevates T_c and reduces ΔT_c, and the LiCl-NaCl system shows superior superconducting properties.

To address the nonlinearity, time-varying nature, and uncertainty in pressure control of plastic hot press machines, a higher-order differential feedback control strategy incorporating FUZZY mathematical algorithms is proposed to enhance the molding quality and process stability of plastic products. By mathematically formalizing fuzzy logic, the system state is discretized into fuzzy sets to capture subtle variations in heat conduction, mechanical structure, and environmental parameters, thereby suppressing pressure signal uncertainty. The designed higher-order controller utilizes higher-order derivative information to reduce sensitivity to rapid pressure fluctuations, minimizing overshoot and oscillations. Defuzzification techniques convert fuzzy outputs into precise control signals, with stan-dard deviation serving as the feedback parameter for optimized control, thereby reducing profile density variations. Experimental validation demonstrates significantly improved profile density uniformity, with average density values closely approaching the preset final density target. Through mathematical modeling and refined regulation, the proposed feedback control method effectively addresses complex pressure control challenges in plastic hot presses. It achieves efficient suppression of profile density fluctuation differences, enhancing the processing quality and process stability of plastic products.

As a pillar of the national economy, the iron and steel industry has long been plagued by high energy consumption and high emissions, making it a core sector for China to achieve the goals of carbon peaking and carbon neutrality. As a representative of high-performance steel products, the green technological innovation efficiency of rare earth steel directly determines the upgrading quality of the iron and steel industry.Taking Group B as the research object, this study focuses on evaluating the green technological innovation efficiency of rare earth steel, aiming to construct a scientific evaluation system and identify the paths for efficiency improvement. Firstly, an evaluation index system was established from the input-output dimension, namely the input side included indicators of human resources (full-time equivalent of R and D personnel), capital (R and D expenditure, environmental protection investment) and energy (comprehensive energy consumption per ton of steel). The output side was divided into desirable outputs (number of patents, sales revenue of green products) and undesirable outputs (SO₂ emissions per ton of steel, COD (chemical oxygen demand) emissions). Secondly, a series of data envelopment analysis (DEA) models were adopted for empirical study, namely the CCR (charnes-cooper-rhodes) model was used to measure the overall efficiency, which was found to exhibit a W-shaped fluctuation; the BCC (Banker-Charnes-Cooper) model was applied to decompose the efficiency, revealing the core contradiction that pure technical efficiency remains stable while scale efficiency becomes a restrictive factor. The SBM model was employed to quantify super-efficiency, further distinguishing the efficiency differences among DEA-effective years; the Malmquist index was utilized to analyze dynamic changes, verifying that the efficiency fluctuation is entirely driven by technological progress. Finally, the Tobit regression model was used to identify influencing factors, namely labor quality, transformation of innovative achievements and intensity of environmental protection investment exert significantly positive impacts, while the efficiency of government fund utilization shows a marginally negative impact. Meanwhile, prominent problems such as insufficient systematic coordination and suboptimal resource allocation were identified. On this basis, several key improvement measures are proposed, including constructing a mechanism of strategic guidance and dynamic regulation, optimizing the system of resource allocation and factor coordination, establishing a mechanism of rigid budget and flexible supplementation, implementing whole-process quality control of patents, and strengthening the dual-track governance of pollutants through the integration of technology and management. This study provides practical references for rare earth steel enterprises to optimize their green technological innovation efficiency.

Lead-containing plexiglass with excellent optical properties can meet the visualization requirements in me-dical, defense, and nuclear fields. In this study, lead-containing plexiglass was prepared via bulk casting polymerization, and the influence of the refractive index of polyethylene glycol dimethacrylate (PEGxDMA, where x=200, 400 and 600) as a copolymer monomer on the optical properties of lead-containing plexiglass was investigated. The shielding performance and mechanical properties of the material were also evaluated. The research results show that lead-containing plexiglass exhibits effective shielding against X-rays; polyethylene glycol dimethacrylate compounds can enhance the optical performance of lead-containing plexiglass, and higher refractive index of PEGxDMA leads to higher transmittance and lower haze in the material. Additionally, polyethylene glycol dimethacrylate compounds exert a toughening effect on lead-containing plexiglass.

Due to the harsh working environment of wind turbine flanges, high requirements are placed on their low-temperature impact performance at -50 ℃. Therefore, by comparing and analyzing relevant indicators such as Ti content, low-temperature impact performance, metallographic structure, Brinell hardness, and impact fracture morphology, the factors affecting their low-temperature impact performance were studied. It was determined that Ti content is the key factor affecting low-temperature impact when the smelting process and main chemical composition are basically the same. The results indicate that, under similar production processes, process parameters, chemical composition, metallographic structure, and Brinell hardness values, Ti content is the key factor affecting the low-temperature impact performance of Q345E/S355 NL wind turbine flange steel; With the increase of Ti content, the low-temperature impact performance of Q345E/S355 NL wind turbine flange steel at -50 ℃ significantly decreases. The reason for the decrease in low-temperature impact performance is the precipitation of TiN inclusions. When the Ti mass fraction is not greater than 0.002 0%, the low-temperature impact energy of Q345E/S355 NL wind turbine flange steel at -50 ℃ can reach over 100 J. When the Ti mass fraction is not less than 0.010 0%, its low-temperature impact energy at -50 ℃ is only below 15 J. In order to ensure the low-temperature impact performance of Q345E/S355 NL wind turbine flange steel, and taking into account the composition design and production process of wind turbine flange steel, it is recommended to control the Ti mass fraction not to exceed 0.002 0%.

Zirconia restorations are widely used in the field of dental restoration. To delve into the impact of clinical adjustment and grinding on the load-bearing capacity of zirconia restorations and provide a scientific basis for their clinical application, 3 mol% yttrium-stabilized zirconia ceramic sintered bodies were selected as the material for preparing test specimens. The specimens were divided into a control group (Group A) and experimental groups (Groups B, C, and D). The specimens in Group A were not adjusted or ground, while those in Groups B, C, and D were adjusted and ground at rotational speeds of 150 000, 200 000, and 250 000 r/min, respectively. Each group of specimens was further divided into three subgroups: unloaded, loaded 10⁵ times, and loaded 10⁶ times. The impact of clinical adjustment and grinding on the load-bearing capacity of zirconia restorations was investigated through fatigue loading tests, flexural strength tests, Weibull analysis, scanning electron microscopy, and X-ray diffraction. The experimental results indicated that an increase in the adjustment and grinding rotational speed enhanced the load-bearing capacity of the specimens but had an insignificant impact on their strength. An increase in the number of fatigue loading cycles reduced both the load-bearing capacity and strength of the specimens. In terms of the material's surface condition, the adjusted and ground material exhibited abrasive wear, and after cyclic loading, micro-cracks and flake-like spalling were observed on the specimen surface. X-ray diffraction analysis revealed that the diffraction results of the specimens were predominantly tetragonal phase, suggesting that adjustment and grinding can remove surface defects from the zirconia restoration material, improving its mechanical properties and load-bearing capacity. In contrast, repeated fatigue loading can induce micro-damage or cracks within the zirconia restoration, reducing its strength. The findings of this study assist dental practitioners in rationally selecting adjustment and grinding parameters and fatigue loading cycles, optimizing the clinical application of zirconia restorations, and enhancing the effectiveness of dental restoration treatments and the long-term stability of the restorations. This study provides crucial guidance for the clinical application of zirconia restorations, aiding in the optimization of adjustment and grinding process parameters and the balancing of adjustment and grinding effects with potential risks, thereby improving the effectiveness of dental restoration treatments and the long-term stability of the restorations.

The surface coating of robotic arms in the power industry must have good insulation performance, block electron transfer, and prevent current leakage and electric shock accidents. Therefore, the preparation and insulation performance analysis of titanium aluminum alloy surface coating for robotic arms were carried out. Using TA15 titanium aluminum alloy as the substrate and titanium aluminum alloy powder as the coating material, a surface coating of titanium aluminum alloy for a robotic arm was prepared by laser cladding method with argon gas as the protective gas and synchronous powder feeding method. The performance of the coating was comprehensively analyzed by microhardness test, friction resistance test, flexural insulation performance test and high temperature insulation performance test to verify the insulation performance of the prepared titanium aluminum alloy surface coating for mechanical arm. The results showed that under the conditions of laser power of 1 100 W and scanning speed of 15 mm/s, the hardness of the prepared coating was the highest, reaching 800HV. After 1 hour of friction testing, the friction coefficient of the coating decreased from 0.83 to 0.68. This helps prevent coating peeling or cracking, thereby maintaining the insulation performance of the coating stable. Meanwhile, the coating was repeatedly bent on the copper rod 7 times without any breakdown issues, indicating that the coating has certain flexural insulation properties; When the temperature reaches 200-360 ℃, the insulation performance of the coating is good. When the temperature reaches 370 ℃, the coating begins to fail and breakdown occurs, indicating that it has high insulation performance under conditions below 360 ℃. This indicates that the coating prepared in this article has excellent insulation performance and can provide strong technical support for the practical application of robotic arms in the power industry.

The image of the scrap pile itself is blurry, and its quality monitoring is affected by various factors, resulting in high noise and difficulty in identifying abnormal situations in the scrap pile. Therefore, a method for automatic identification of scrap pile anomalies under the texture mapping of unmanned aerial vehicle oblique photography point cloud is proposed. Using drone oblique photography to obtain images of scrap steel piles, removing the borders of the scrap steel pile images, and then performing distortion correction, smoothing, and segmentation. Combined with the drone's shooting angle, the images are registered. Map the processed image to a three-dimensional space, generate corresponding point cloud data, and combine the point cloud data with the original image to repair the texture information in the image, thereby obtaining the repaired scrap pile image. Then extract the color features of different regions in the image, calculate the color feature entropy value, and determine whether the current region is an abnormal region based on the entropy value. The experimental results show that in practical applications, the overlap between the abnormal identification results of the scrap pile and the actual results is as high as 98.72%, indicating high accuracy.

The frame of a mining truck is usually composed of a large number of complex geometric structures, including beams, plates, connectors, etc. These structures have different shapes and sizes, and their geometric features need to be accurately reproduced during modeling, which puts high demands on the force distribution and numerical simulation of the elements. Therefore, a numerical simulation analysis method for the complex structural stress of the metal bearing frame of mining vehicles is proposed. In depth analysis of the mechanical characteristics of actual mining vehicle metal bearing frames, construction of balance equations for mining vehicle operation process and mechanical equations for three different working conditions of mining vehicle linear operation, braking operation, and turning operation, construction of finite element analysis model for mining vehicle metal bearing frames, division of structurally complex mining vehicle metal bearing frames into several finite elements for node and finite element element force and displacement analysis, combined with all finite element analysis results, to achieve numerical simulation analysis of the overall force of mining vehicle metal bearing frames. Through experimental verification, this method can present stress distribution data of metal bearing frames under different working conditions, and is highly consistent with actual results. Through experimental analysis, the maximum stress and maximum deformation of the metal bearing frame, as well as the safety factor under this operating state, can be obtained. Potential problems in the frame structure can be identified, thereby promoting the optimization and development of metal bearing frame design for mining vehicles.

Traditional power connection fittings are mostly manufactured from steel with hot-dip galvanizing for corrosionprotection. With the trend toward low-carbon power systems and higher requirements for corrosion resis-tance, aluminum alloys, which are greener and more environmentally friendly, have been increasingly adopted for power connection fittings in recent years. A comparative study on salt spray corrosion resistance was conducted among three aluminum alloys (7075, 7A04, 6082) and two steels (Grade 35, Q345R). The results show that the corrosion rates of the uncoated aluminum alloys are lower than those of the ungalvanized steels. Considering mechanical properties, processability and intergranular corrosion resistance of 7075, 7A04 and 6082, 6082 aluminum alloy, which exhibits superior plastic deformability and impact resistance, is finally selected for manufacturing power connection fittings. Furthermore, three surface treatments (anodizing, shot peening and passivation) were applied to 6082 aluminum alloy right-angle clevises. Salt spray corrosion tests indicate that anodizing provides the optimal corrosion resistance. It is demonstrated that 6082 aluminum alloy with anodizing treatment has broad application prospect in the production of power connection fittings.

To enhance the mechanical properties and seismic resistance of large-section shear walls, the application effect of high-performance niobium-vanadium microalloyed steel was studied. Using raw iron, molten steel and other materials as the base, by adding niobium iron, vanadium alloys and other auxiliary materials, high-performance niobium-vanadium microalloyed steel reinforcing bars were prepared through forging and rolling processes. These reinforcing bars were applied to the welding construction of the shear wall framework and the concrete pouring was completed. Finally, a large-section shear wall specimen was constructed. The fracture mechanism and mechanical properties of the steel were analyzed, and its application effect in large-section shear walls was verified. The test results show that the heating temperature of the steel billet has a significant impact on the mechanical properties of the high-performance niobium-vanadium microalloyed steel reinforcing bars. At 500-650 ℃, as the temperature increases, the plasticity of the reinforcing bars improves, and the fracture contraction rate increases; at 650-950 ℃, the cross-sectional contraction rate of the reinforcing bars rises to 98%, but at 1 250 ℃, the cross-sectional contraction rate of the reinforcing bars decreases instead. At 950 ℃, the reinforcing bar exhibits the best plastic performance, while at 1 250 ℃, the reinforcing bar shows obvious toughness fracture characteristics. The conclusion is that an appropriate heating temperature (about 950 ℃) helps to exert the best plastic performance of niobium-vanadium microalloyed steel, which is of great significance for improving the seismic performance of large-section shear walls.