Based on the orthogonal test method of four factors and three levels, TiCN films were prepared on Cr12MoV die steel under different process parameters using PVD multi-function ion coating machines. The effects of different process parameters on mechanical and friction performance of TiCN thin films were studied, and the preparation process parameters of the film were optimized. The results show that the influence weight of factors on the bonding force of TiCN thin films is methane and nitrogen flow ratio > arc current> total gas flow> partial pressure, and the influence weight of factors on the hardness is methane and nitrogen flow ratio> total gas flow> partial pressure> arc current. The methane and nitrogen flow ratio affects the mechanical properties of TiCN films mainly by changing the carbon content. The TiCN film obtained by the process scheme with the bonding force as the index has the best performance, and the process parameters are the total gas flow of 450 sccm, methane and nitrogen flow ratio of 5∶1, partial pressure of 200 V, and current of 60 A. The hardness value of as-prepared TiCN film is 3 456.76 HV, the binding force is 36.7 N, and the average friction coefficient is 0.281 3, which significantly improves the anti-wear performance of the substrate.

Utilizing numerical simulation techniques in combination with COMSOL Multiphysics software, a novel MPCVD system was proposed. The structural parameters of the system was optimized through simulation under a microwave electric field. At the optimal dimensions, the flow field distribution, the plasma and electric field distribution of the device were simulated and calculated. Finally, diamond films were deposited, and the effects of methane and oxygen content on the growth of diamond films were studied. The results show that under the optimal dimensions, the highest electric field intensity is above the substrate holder, reaching 6 430 V/m, and a stable hemispherical plasma completely covering the substrate holder without secondary plasma formation is obtained at an input power of 4.5 kW and a pressure of 80 torr. The optimal air inlet of the device is located directly above, and two exhaust outlets are symmetrically distributed below. The higher CH₄ content leads to a faster deposition rate, but the excessive CH₄ content degrades the crystal quality. When the volume ratio of CH₄ to H₂ is 6%, the crystal quality is better. As the O₂ content increases, the diamond deposition rate increases first and then decreases. When the volume ratio of O₂ to H₂ reaches 2%, the deposition rate approaches 0. When the volume ratio of O₂ to H₂ is 0.5%, the crystal quality is better.

To study the aging mechanism of high polymerization materials PEEK/GF after ion beam activation, they were activated with argon (Ar), hydrogen (H₂), oxygen (O₂), and a mixture of hydrogen and nitrogen (H₂+N₂), and stored in different media, including atmosphere, pure water, absolute ethanol, and vacuum, for 1-90 d. The changing pattern of the surface properties was analyzed by testing infrared spectroscopy and surface contact angle. On this basis, the copper film was deposited by magnetron sputtering coating technology, and the adhesion of the copper layer was determined qualitatively and quantitatively by scribing test and drawing test. A comprehensive study was then carried out in conjunction with the surface characteristics of the substrate. The results show that the PEEK/GF materials activated by different gases and stored in different media show a strong time-dependent behavior. When the storage medium is the same, H₂+N₂ activation has the best effect of improving the aging, and the rest are O₂, H₂ and Ar in order. When the activation gas is the same, storing the material in absolute ethanol has the best effect of improving the aging, and the rest are pure water, atmosphere and vacuum environment in order. Ion beam activation with H₂+N₂ or O₂, and storage in hydrophilic medium can improve the activity of the substrate and delay timeliness effectively. The adhesion of copper films deposited on PEEK/GF immediately after ion beam activation is up to level 1/11.51 MPa, while the adhesion of copper films deposited on PEEK/GF after storage is significantly lower, and the maximum is only level 1/5.40 MPa.

Silicon oxide thin films were fabricated on the glass substrate using radio frequency magnetron sputtering method by controlling variables. The influence of process parameters including gas pressure, sputtering power, substrate temperature on the thickness, roughness and transmittance of the silicon oxide film were studied using the step meter and spectrometer. The results show that the film roughness is the lowest at sputtering pressure of 0.8 Pa, substrate temperature of 150 ℃ and sputtering power of 310 W. The film transmittance is maximized at sputtering pressure of 0.8 Pa, substrate temperature of 250 ℃, and sputtering power of 250 W.

The wettability of liquid lithium (Li) on the substrate surface is a key factor to determine the performance of the liquid Li first wall. A wettability research platform for the liquid metal and solid materials was designed, and the key problems of the platform are simulated and calculated theoretically. The ANSYS software was used to simulate the stress and heat distribution of the platform test chamber and injection system. The results show that the maximum deformation of 304 stainless steel test chamber with 250 mm outer diameter and 3 mm wall is about 0.045 mm, and the maximum stress intensity is 29.876 MPa, which is less than the allowable stress of 137 MPa under one atmosphere pressure. The maximum equivalent stress is about 26.708 MPa, which is less than the yield limit of 205 MPa. The limit distance between the needle and heating wire is 50 mm when the heating wire temperature is 400 ℃. When the internal pressure difference between the syringe and test chamber is 600 Pa and -465 Pa respectively, the liquid Li can be inhaled and dripped through a 1 mm diameter needle. During the operation of the system, filling the test chamber with argon gas of more than 0.26 Pa is conducive to protecting the wall and observation window of the test chamber, and reducing the influence of the detection material film. Based on the above results, the platform was successfully built and Li with a diameter of 3 mm was dripped out.

The dynamic balance design method for variable pitch rotor of dry screw vacuum pump was studied. Two kinds of five groups of weight loss holes were designed on the rotor tooth surface by mass division method. Combining with parametric modeling technology and NSGA-II algorithm, the optimal parameters and layout angles of weight loss holes were successfully obtained, so as to optimize the mass distribution. SolidWorks was used for 3D modeling, and its API interface was used for secondary development. Visual Studio was used to develop form programs to realize data interworking during modeling and optimization, as well as automatic updating of model parameters. The results show that the dynamic balancing performance of the rotor after weight reduction is significantly improved. The method simplifies the traditional dynamic balancing design process and realizes the automatic calculation of dynamic balancing, thus greatly improving the efficiency and accuracy of the design.

To address the challenges of low steam penetration efficiency and uneven distribution in microscale lumen structures, this study investigates the regulatory mechanism of vacuum pulsation parameters on steam mass transfer, aiming to improve penetration performance and energy utilization. A steam diffusion dynamics model coupling pulsation frequency (0.5~2.0 Hz) and pressure amplitude (5~15 kPa) was developed, and computational fluid dynamics (CFD) simulations were employed to reveal how pulsating pressure fields influence steam phase change and boundary layer disturbances. A dedicated vacuum pulsation experimental platform was constructed, integrating high-speed micro-imaging and X-ray micro-CT to quantitatively analyze steam penetration depth and 3D distribution under various parameter conditions. Response surface methodology was used to optimize the parameter combinations. The results show that under pulsation conditions, the penetration uniformity index improved by approximately 21%, and the terminal steam saturation reached 0.78±0.05, representing an approximately 50% increase compared to static conditions. At the optimal parameter combination of 1.2 Hz/10 kPa, the unit energy efficiency index (η=5.06 s/J) achieved its highest value, representing an approximate 40% improvement over the baseline, with the corresponding key performance indicator (KPI) reaching 2.37 g/(kW·s), a 58% improvement over the standard. The study confirms that vacuum pulsation parameters can synergistically enhance steam transfer efficiency and energy performance, significantly improving permeation in microscale structures, and providing theoretical guidance and optimization strategies for applications such as microchannel drying, instrument sterilization, and mass transfer in porous media.

Finding environmentally friendly alternatives to SF₆ circuit breakers is an urgent issue in the field of high-voltage switchgear. This article proposes a design concept and overall plan for a fluorine free environmentally friendly circuit breaker using dry air as the insulating gas. A numerical simulation model of 145 kV fluorine free environmentally friendly circuit breaker was established using 3D design software, and numerical simulatlon software was used for simulation analysis to obtain the electric field distribution of key parts of the circuit breaker's external insulation. The research results show that the electric field strength of the outgoing conductor supported by the three-phase dynamic and static ends of the circuit breaker is the highest under different working conditions. By optimizing the structure of the dynamic and static end supports and the connection parts of the conductor, the maximum electric field strength of the external insulation structure of the circuit breaker was reduced by 34.40%, which provides a theoretical basis for the development of 145 kV fluorine free environmentally friendly circuit breakers.

Under dynamic working conditions, the transient signal of the electric vacuum pump assisted braking system of new energy vehicles has multi-modal nonlinear coupling characteristics, which can easily lead to misjudgement of fault modes. Therefore, this study proposes a new fault diagnosis method. Firstly, by real-time monitoring of core parameters such as the maximum vacuum degree and pumping rate during the operation of the vacuum pump, a dynamic characteristic model of the electric vacuum pump assisted braking system is constructed. Secondly, starting from the aspects of current and pressure, the transient characteristics of the electric vacuum pump assisted braking system are obtained, and continuous transient signals of the system operation are generated; Then, to address the multi-modal nonlinear coupling characteristics of the signal, the transient signal is decomposed using wavelet analysis theory, and the energy entropy features of each frequency band signal are extracted. By finely characterizing the inherent nature of the fault features, the identification and discrimination of the fault features are improved, and a vacuum failure feature library is established; Finally, an intelligent fault diagnosis model is constructed by combining ResCNN network and XGBoost. Energy entropy features are input into the model, and deep level representative features are further explored through convolutional pooling operation. Then, relying on the automatic classification ability of XGBoost, the deep level features are efficiently and accurately classified to output the fault diagnosis results of the braking system. The results show that the ACC value of this method reaches 0.97, which realizes the accurate description of the running state of the braking system, effectively shortens the vacuum establishment time, and reduces the pressure fluctuation and energy consumption of the system.

Traditional fault diagnosis methods for helium leak detection equipment provide limited accuracy due to the inability to intuitively represent fault characteristics and heavy reliance on experts. A time series image generation scheme combined with the convolutional neural networks (CNN) is proposed for the sensor data of helium leak detection equipment, which performs data-driven analysis and fault classification on the fault data. Thereby, the faults of helium leak detection equipment can be diagnosed more accurately. Firstly, a more intuitive grayscale transformation was proposed to convert one-dimensional time series signals into grayscale images for visual representation, in order to adapt to different helium leak detection equipment fault diagnosis scenarios. Then, the LeNet-5 CNN model was optimized, and LeNet-5s CNN model with faster computing speed was designed to maximize recognition accuracy, and a dual model detection method was proposed for complex detection tasks. Finally, the effectiveness of the algorithms was verified through experiments. The results show that the improved model has a certain improvement in accuracy compared to the pre-improved one, and the dual model detection method has good recognition performance for all three types of faults in this complex detection task.

Vacuum on-load tap changers (OLTC) are key components of electrical systems, relying on vacuum arc extinguishing technology to ensure stable voltage regulation. However, under high load and high current conditions in large hospitals, vacuum degradation, contact ablation, and insulation contamination pose significant challenges to operational reliability. This study proposes an intelligent multi-modal diagnostic method for vacuum OLTCs by integrating vacuum-specific vibration characteristics and electrical parameter analysis. First, based on the mechanical dynamics of vacuum arc suppression, a Hankel matrix is constructed from vibration signals, and Singular Value Decomposition (SVD) with Fast Fourier Transform (FFT) filtering is applied to eliminate noise interference caused by vacuum chamber micro-vibrations. Second, from the perspective of vacuum arc energy balance, key electrical parameters including transient current harmonics and dielectric recovery voltage are extracted as fault indicators. Finally, a multi-class Support Vector Machine (SVM) optimized by a binary tree structure is employed to fuse vibration and electrical features, achieving accurate identification of six typical vacuum-related faults (e.g., vacuum leakage, contact oxidation). Experimental results demonstrate 98.2% diagnostic accuracy, with particular advantages in early-stage vacuum pressure decline detection. This method provides a novel solution for real-time monitoring of vacuum integrity in OLTCs, significantly enhancing the safety of vacuum-based power regulation systems.

Vacuum furnace heating element plays a crucial role in determining the temperature uniformity, heating efficiency, workpiece quality and energy consumption, which is the most important focus in the furnace design and research. This article reviews the domestic and international literature progress of heating elements, including materials and shapes, power specifications, power connection methods, dimensions and quantities selection, and installation layouts / configurations. Firstly, the material type, shape, applicable atmosphere and vacuum degree for heating elements are summarized. Secondly, the selection of power voltage and connection method is analyzed, and the applicable situations of seven empirical methods for power calculation are compared. Finally, to enhance the temperature uniformity and service life, the heating element size and installation layouts for different types of furnace are summarized. To meet the requirements of vacuum furnace for precise temperature control, energy saving and consumption reduction, future efforts should be made on the modularized structure design of heating elements, the research and development of novel corrosion-resistant and anti-oxidation coatings, along with the integration of high-precision sensors and intelligent algorithms. It can thus realize automatic monitoring and optimal control of heating element temperature.

To address the demanding requirement for precise temperature uniformity in specialized heat treatment processes for large-sized special materials in the nuclear industry, a dedicated vacuum heat treatment furnace was first developed and designed. Subsequently, the large uniform temperature zone for processing two types of products was simulated. Through iterative optimization based on simulation results, the power distribution of heaters and the configuration of radiation shields were refined. Finally, the on-site experiments were conducted to validate the distribution range of the uniform temperature zone during the holding phase. The results demonstrated that the as-developed vacuum heat treatment furnace achieved a temperature uniformity of ±3.0 ℃ within a 500 mm×500 mm×3 000 mm uniform temperature zone under operating conditions. Experimental validation showed high consistency with simulation results, confirming that the furnace can meet the design requirements for specialized heat treatment processes of large-sized nuclear materials.

The effects of additives on the micro structure evolution and mechanical properties of cemented carbide were investigated. Tungsten cobalt alloy was used as matrix, titanium carbide and other auxiliary materials were added, and the cemented carbide samples with different TiC content were prepared by granulation, pressing and sintering. The microstructure, coercive force and bending strength of the alloy were analyzed in detail by scanning electron microscope, hysteresis loop measuring instrument and three-point bending tester. The results show that the addition of additives significantly changes the microstructure of hard alloys. With the increase of additive content, the grain size of the alloy gradually refines and the distribution becomes more uniform. The coercivity of alloy specimen with 15 wt% TiC reaches maximum value of 5.8 kA·m^-1, while the bending strength of alloy specimen with 20 wt% FiC is the highest at the same sintering temperature, reaching 840 MPa. The additive content has a significant control effect on the micro structure and mechanical properties of cemented carbide, and the additive content has a positive correlation with the bending strength of the alloy. By optimizing the content of additives, the comprehensive performance of hard alloys can be effectively improved.