Abstract: γ-TiAl alloy, with its excellent creep resistance, oxidation resistance, and corrosion resistance, is regarded as one of the most promising materials in high - end fields such as aerospace. In aerospace and other fields, the requirements for the surface friction and wear performance of components are extremely stringent. However, the surface properties after traditional processing have limitations. Therefore, it is of great significance to seek more excellent processing methods to improve the friction and wear characteristics of the material. In this paper, ultrasonic - assisted high - temperature milling was carried out on the γ-TiAl cladding layer prepared by the laser directed energy deposition technology and the γ-TiAl castings, and the friction and wear performance of the machined surfaces was analyzed. The experimental results indicate that, compared with castings, the cladding layer has better surface wear resistance due to its smaller internal structure size. In comparison with the surface of the cladding layer processed by conventional machining, the friction coefficient and wear cross-sectional area of the surface processed by ultrasonic machining are reduced by 4.1% and 57.27% respectively, demonstrating that the surface processed by ultrasonic - assisted machining exhibits more excellent friction and wear performance. Read More

Abstract: In this paper, the optimal parameters of the laser concentric circle (from outside to inside) scanning processing method are investigated by infrared nanosecond laser perforation of nickel-based high-temperature alloy (IN718) in air. Based on the optimal parameters, the effects of the backwater assisted and different graded scanning optimization on the morphology of microvias are investigated, and the advantages of the optimized scanning method are summarized. The results show that the laser energy distribution on the material surface can be adjusted by scanning path graded optimization in air to eliminate the negative effect of excessive heat accumulation in the center of the scanning path to improve the taper of the microporous holes, and the combined effect of water-assisted water evaporation and boiling scouring, water buoyancy, and impact force generated by the collapse of bubbles can reduce the scope of the heat-affected zone and reduce the melt buildup and spraying of the microporous holes at the inlet and outlet of the microporous holes. The combined effect of water buoyancy and the impact force generated when the bubble collapses can reduce the scope of the heat-affected zone and minimize the accumulation of melt and spatter at the inlet and outlet of the microvia. It provides a reference for water-assisted infrared nanosecond laser processing and its optimization process. Read More

Abstract: In order to improve the wear resistance of 42CrMo steel for rock drill bits, NiCrFeCu-45%WC composite cladding layer was prepared by laser cladding technology, and the influence of laser power at 1500W-1800W on the organization evolution and mechanical properties of the cladding layer was systematically investigated. The XRD, SEM/EDS and friction wear tests show that the physical phase of the cladding layer is dominated by γ-(Ni,Fe) solid solution, accompanied by the formation of WC, W2C and Cr23C6/M7C3 carbides. When the power was increased to 1600 W, the trace WC decomposed into W2C particles, and the grains remained small in size due to heterogeneous nucleation and Zener pinning effect, and the microhardness of the cladding layer reached a peak (average 747.6 HV1.0), which was 1.4 times higher than that of the substrate, and at this time, the wear rate was at a minimum of 1.6×10-2 mm3/Nm. The study showed that the The optimal wear resistance of the cladding layer at 1600 W is achieved through fine grain strengthening, hard phase dispersion and carbide synergism. Read More

Abstract: For the casting of the workpiece number characters are small, and the blade surface reflection, the target and the background of the contrast is low, resulting in the human eye recognition difficulties, low efficiency and other issues. In this paper, a machine vision-based casting workpiece number automatic identification system is designed. First of all, through the high-resolution industrial camera to obtain the image to be recognized, and to be recognized image preprocessing; and then according to the target area characteristics to determine the region of interest, extract the character features to establish a character library; and finally the application of character templates in the character library to achieve automatic recognition of characters in the image to be measured. After the actual test shows that the system can meet the casting workpiece number automatic identification needs, and stable performance, has good practicality and feasibility, thus proposed to improve the identification system. Whether in the generation of the manufacturing process, or testing and maintenance process, need to be organized according to the workpiece number, workpiece number is equivalent to each casting ID, can be convenient to record and query the casting in the generation of the manufacturing process of the relevant information as well as testing and maintenance of defects found in the process of information. Read More

Abstract: The capacitance-reduced H-bridge cascaded static synchronous compensator (CHB-STATCOM) uses ramp feedforward to suppress the phase-to-phase voltage unbalance of the dc-side voltage when the compensated power jumps, and its minimum transition time T is 10ms, which fails to satisfy the shortest transition time T is 10ms, which cannot meet the demand of fast response of the device. To address this problem, this paper gives the relationship between the commanded power tapering time T less than 10ms and the inter-phase DC voltage based on the CHB-STATCOM control principle of capacitance reduction. The equations on increasing the DC component under the constraints of the upper and lower boundary constraints are developed and the upper and lower boundary constraints are taken into account under the constraints of the CHB-STATCOM operating principle of decreasing capacitance value .According to the characteristics of the constraint equations, a method for solving the constraint equations is proposed, and the solution results are analyzed by specific examples. The effectiveness of the method in improving the response time is verified by simulation with MATLAB software. The conclusions of the study can also provide a reference for the device to select the power jump time. Read More

Abstract: In this paper, the experiment of IN718 superalloy was carried out with the aid of liquid, and the influence of liquid aid on key indexes such as hole taper and diameter of inlet and outlet was systematically analyzed. At the same time, the chemical element composition of the hole wall was detected, and the thickness of oxide layer formed in different environments during machining was studied. Finally, the processing mechanism of IN718 superalloy nanosecond laser drilling under liquid-assisted conditions is discussed. The results show that both water-assisted and liquid-assisted can improve the quality of micropores in different degrees compared with the condition without auxiliary field in air, especially the effect of liquid-assisted is the most significant. Under this condition, the hole taper is reduced by 67%. In addition, with the help of liquid, the content of oxygen element in the pore wall of micropores is greatly reduced, and the element composition is closer to the base material. This study provides important theoretical support and technical optimization direction for nanosecond laser drilling technology. Read More

Abstract: In view of the problem that the original system cannot truly display the geographical environment of engineering, the design method of the 3D digital system of power transmission line based on digital twin is studied. In the hardware design, the transmission line network architecture is arranged, embedded in the OPC-UA server, and the sensor node location is bound. In the software design, the spatial database of transmission and transformation lines is established, the digital twin 3D virtual model is constructed, and the design of 3D digital system is completed. With complex area transmission and transformation line construction project as the object of experiment, the experimental results show that: select the location of the multiple scenarios line segment distance measurement, two groups of traditional methods to the actual distance measurement error, generated topographic map deformation, and the system can completely restore the transmission line segment distance, has the practical application effect. Read More

Abstract: With the global energy structure undergoing a transition towards low-carbonization, supercritical coal-fired power generation technology, due to its high efficiency and low emission characteristics, has become one of the core paths for the clean-up transformation in the power generation sector. This paper mainly discusses and summarizes three types of methods for the mechanism modeling, data-driven modeling, and hybrid modeling of the DC boilers in supercritical power generation units. The hybrid modeling integrates the mechanism and data-driven methods, possessing both physical interpretability and data adaptability, and holds significant theoretical and application value. Read More

Abstract: With the rapid development of the global economy and the continuous growth of population, the shortage of water resources has become increasingly prominent, posing a significant challenge to sustainable development. Particularly in arid and semi-arid regions, freshwater resources are extremely scarce. Therefore, the development of efficient water collection technologies is particularly important. Atmospheric Water Harvesting (AWH) technology, as an innovative method to extract water from the air, has received widespread attention in recent years. AWH technology can be divided into fog collection technology in high-humidity environments and adsorption-based atmospheric water collection technology in low-humidity environments. This review summarizes the latest research progress in humidity-adaptive atmospheric water collection materials, focusing on the research findings of Deng Kaimin in his master's thesis titled "Preparation and Properties of Humidity-Adaptive Atmospheric Water Collection Materials," as well as other related research advancements. Read More

Abstract: This paper examines the fire risk in subway stations using FDS software, establishing fire models for both subway cars and platforms. It simulates a luggage fire scenario to investigate its impact on personnel evacuation. The study reveals that luggage fires spread rapidly within subway cars and on platform levels, leading to a sharp decline in visibility, significant increases in temperature and CO concentration, thereby posing a severe threat to evacuation efforts. By constructing and simulating an evacuation model, this research calculates evacuation times under various scenarios and compares these with the time it takes for danger to arrive. Results indicate that evacuation can be completed before danger arrives in all simulated fire scenarios. This research proposes strategies for subway fire prevention and control, including the rational layout of subway facilities, utilization of advanced firefighting equipment, and establishment of fire zones, aiming to reduce the likelihood and spread of fires, enhance subway fire prevention and control capabilities, improve personnel evacuation efficiency, and ensure operational safety. Read More

Abstract: Pressure vessel is widely used in the energy industry, military industry, scientific research and many other fields, the importance of its safe operation is self-evident, the safety of pressure vessel and pipeline has been an important research topic. For the safety assessment of defective vessels and pipelines, this paper firstly introduces the research results of the latest standards of defective equipment and pipelines, gives the latest progress of defect assessment theory, briefly reviews the application status of safety assessment of defective vessels, and finally proposes the current situation of domestic defect assessment, providing a basis for the safety evaluation of defective vessels and pipelines. Read More

Abstract: Under the background of the increasing energy demand and the tightening environmental protection requirements, steam turbines, as one of the key operating devices in power plants, hold significant importance for the modern power system. This paper conducts research by retrieving international literature journals and applying the literature analysis method, focusing on the simulation technology of steam turbines in supercritical power generation units. It summarizes three types of methods: mechanism modeling, system identification modeling, and composite modeling, aiming to provide references for subsequent related research. Read More

Abstract: To address the limitations in positioning accuracy and environmental adaptability of vibration-aware target monitoring systems, an enhanced TDOA acoustic source localization method based on Chan-Taylor collaborative algorithm is proposed in this study. A two-phase collaborative localization model is constructed by integrating the high-precision characteristics of Chan's algorithm with the strong robustness of Taylor series expansion method. A virtual-real mapped simulation monitoring platform is established through digital twin technology, achieving dynamic interactive verification between physical and virtual spaces. Experimental results demonstrate that the improved algorithm attains 92.7% positioning accuracy in target trajectory reconstruction. Under virtual-real fusion testing conditions, the system achieves continuous target tracking within an 80-100 meter radius monitoring range in complex terrains. Read More