Nitrogen-doped carbon films (NCFs) are functionalized thin-film materials grown by introducing nitrogen atoms into a carbon matrix through chemical or physical methods. These films exhibit excellent mechanical properties, chemical stability and tunable functionality. The most common synthesis approaches for the preparation of NCFs include chemical vapor deposition, physical vapor deposition and pyrolytic synthesis. Application studies demonstrate that NCFs significantly enhance surface anti-corrosion performance by effectively blocking the penetration of corrosive media, and reduce the corrosion current density of metal substrates by 1-2 orders of magnitude. In energy storage and conversion systems, NCFs serve as high-performance electrode materials, delivering elevated specific capacitance and robust cycling stability. For electronic devices, their high conductivity, transparency and flexibility offer novel pathways for advancing flexible electronics.

The lack of anti-corcosion performance on the inner surface of the tube seriously limits its service life, so it is particularly important to prepare a high quality coating on the inner wall of the tube. In this paper, the bipolar high power impulse magnetron sputtering technology is used to place the cylindrical target as the cathode in the tube to prepare the high-quality Cr coating. Through SEM, XRD, scratches, electrochemical corrosion and high temperature oxidation, the influence of the deposition temperature on the microstructure, mechanical properties, corrosion resistance and oxidation resistance of Cr coating deposited in the tube was studied. The results show that as the deposition temperature increases from 25 ℃ to 300 ℃, the Cr coating exhibits a preferred (110) orientation; affected by thermal stress, the film exhibits the optimal toughness at 100 ℃; the coating prepared at 25 ℃ exhibits the highest corrosion resistance and high-temperature oxidation resistance. Among its properties, the corrosion current density can be as low as 4.9×10^-4 A·cm^-2, along with the smallest oxide layer thickness and the least oxidation weight gain. The smaller grain size and higher density inhibit the diffusion of corrosive media and oxygen. When the deposition temperature is 100 ℃, the corrosion resistance and oxidation resistance of the coating are similar to those at 25 ℃. Considering its microstructure, mechanical properties, and service performance comprehensively, the coating deposited at 100 ℃ exhibits the optimal overall performance.

Etching LNOI (lithium niobate on insulator) usually uses amorphous silicon thin film as a mask. When depositing amorphous silicon thin films onto LNOI surfaces by PECVD equipment, blistering often occurs. Such small bubbles are mostly between 5 μm and 60 μm in size, and they can affect the morphology of LNOI etching. It was found that bubbles in amorphous silicon thin films may be caused by surface defects in lithium niobate thin films. The oxygen atoms on the surface of these defects combine with hydrogen in the amorphous silicon film, breaking the Si-H bond and causing an increase in local tensile stress in the film, resulting in foaming of the amorphous silicon film. Through comparative experiments, it was found that depositing a 50 nm silicon dioxide film to isolate defects on the surface of lithium niobate film before depositing amorphous silicon film can solve this process problem. This provides a reference for depositing flat amorphous silicon thin films on LNOI surfaces using PECVD equipment.

In accelerator-based boron neutron capture therapy (BNCT) device, the Li target is commonly employed for neutron production. However, the lifetime of Li target is significantly reduced due to the high heat load deposition. Consequently, the target capable of withstanding high heat load is critical for ensuring stable operation of BNCT device. A liquid Li target module which is capable of withstanding heat fluxes exceeding 30 MW/m² in vacuum environment is designed in this paper. The module can maintain the liquid Li temperature below the safe threshold of 600 K even under irradiation by a 50 kW high-energy proton beam. The key components of the liquid Li target module include a nozzle, a concave back plate, a collection tank and heating wire. The effect of nozzle width, Li flow rate, and concave back-plate radius on the high-heat-flux removal capability of the module were simulated. The results demonstrate that, with liquid Li film thickness increasing from 1.2 mm to 2.3 mm as nozzle width increases from 1.5 mm to 3.0 mm, the surface temperature rise decreases from 82 K to 52 K. Furthermore, no significant further improvement in the heat removal capability of the target is observed when the nozzle width is increased beyond 3.0 mm. While increasing the liquid Li flow rate from 7 m/s to 14 m/s reduces the maximum temperature rise from 91 K to 46 K, the reduction in temperature rise gradually diminishes. When decreasing the concave back-plate radius from 500 mm to 250 mm, the maximum temperature rise of liquid Li decreases from 77 K to 43 K. Compared to a flat-plate structure, the concave design can effectively improve the uniformity and stability of the Li film. These findings provide valuable guidance for the engineering implementation of liquid Li targets and offer a feasible approach for ensuring stable operation of boron neutron capture therapy systems.

Accelerated life tests were conducted on the reliability of the M-type cathode assembly for applications in space microwave tube. The experiment results showed that the reliability of the thermocouple strongly depends on the polarity of the electrode. When the filament is connected to a negative voltage of the power supply and the cathode is connected to a positive voltage, the life of the heater assembly is much longer than that of the reverse connection one. Further experiments show that the main cause of heaterl short circuit is due to the diffusion of impregnated emission material into the insulation layer of the heater assembly. To this end, a partition is added between the cathode substrate and the heater assembly to prevent short circuits in the thermoelectric components and extend the lifespan of the cathode. In order to improve the thermal efficiency and impact resistance of the cathode, molybdenum ruthenium alloy solder is used to weld the cathode cake and the support cylinder together.

The degradation properties of ethylene tetrafluoroethylene (ETFE) composites under the synergistic effects of atomic oxygen and ultraviolet radiation in low earth orbit were investigated through ground-based simulation experiments. The mass loss, surface topography and elemental composition changes of ETFE were measured and analyzed after exposure to varing cumulative fluxes of atomic oxygen (equivalent energy of 5 eV) and UV irradiation (wavelength range 200 - 400 nm). The results show that there are two stages in the process of material erosion: rapid mass loss due to chemical bond breaking and volatile products escaping at the beginning stage; A dense carbon rich layer forms on the later surface, delaying the penetration of atomic oxygen and UV photochemical reactions, and hence the rate of erosion is slowed. SEM analysis showed that the surface of the material changed from a smooth material structure to a rough material surface with gullies and holes after atomic oxygen and UV irradiation, and the light transmission disappeared. From XPS analysis, the main causes of erosion slowing were defluorination oxidation and carbon reconstruction, which showed a large reduction in the ratio of fluorine to carbon. The dynamic degradation rules of ETFE in LEO atomic oxygen and UV are revealed in this paper, which provide a theoretical basis for the lifetime assessment of ETFE materials and the design of space environment reliability.

Vacuum Insulation Panel (VIP) is a kind of high-performance insulation material, which realizes extremely low thermal conductivity through the synergistic effect of vacuum technology and porous core material, and is widely used in green building, low-temperature cold chain, ultra-low-energy appliances, etc. It is an important direction for the development of insulation and energy-saving materials in the future. Most of the traditional VIP use glass fiber as the core material, but there are problems such as difficult to degrade and recycle, and prone to causing environmental pollution during production. Plant fiber is expected to solve the above problems owing to its wide source, degradable, green and other characteristics. However, because of its high thermal conductivity and poor mechanical properties, plant fiber needs inorganic fiber as a reinforcing phase to improve the overall performance of VIP. Therefore, in this paper, poplar fiber was selected as the core material matrix, and centrifugal glass wool was used as the reinforcing fiber to prepare a composite core material VIP with excellent overall performance, and the composite core material micro-morphology, uniformity, and compression rate and resilience were tested. The thermal, mechanical and aging properties of the as-prepared VIP were investigated. The results show that the comprehensive performance of poplar fiber composite core VIP is excellent, along with the centrifugal glass wool content increasing from 0% to 75 wt.%, the thermal conductivity of poplar fiber composite core decreases by 31.78%, the thermal conductivity of poplar fiber composite core VIP decreases by 50.05%, the tensile strength increases by 420.21%, and the sensitivity of VIP to air pressure is also decreased.

The vacuum chamber is an important component of vacuum equipment, and reasonable design and calculation of the vacuum chamber is the cornerstone of safe operation of vacuum equipment. This article takes the vacuum chamber of a certain space environment simulation device as an example to explore the design of the wall thickness of the vacuum chamber using the formula method in the design manual, the GB/T 150 diagram algorithm, and the GB/T 4732 formula method. It is concluded that the wall thickness designed according to the formula method in the design manual is relatively safe. By conducting finite element analysis on its strength and stability, and comparing the results of standard design with those of finite element analysis, it is found that the allowable external pressure values obtained from the GB/T 150 chart method, GB/T 4732 formula method, and ANSYS nonlinear buckling analysis are relatively close. This can provide a reference for the reliability and economic rationality of the vacuum chamber.

EUV lithography is also called extreme ultraviolet lithography, which uses extreme ultraviolet light with a wavelength of 13.5 nm as the light source. Extreme ultraviolet light is easily absorbed by many materials, including air, so EUV lithography can only operate in vacuum environment. At the same time, EUV lithography has special requirements for vacuum system. In particular, vacuum system with good compatibility plays important impact on improving the life and yield of the EUV lithography. This paper reviews the acquisition of the specific vacuum environment in the main chambers, design of compatibility, influence of vacuum system materials on the quality of lithography, and the methods of contamination monitoring in the vacuum environment of the EUV lithography through the vacuum technology involved in the key architecture and process of the EUV lithography.

Heating element parameters are the key factors affecting the temperature uniformity and workpiece sintering quality for vacuum sintering furnaces. This study investigates the effects of heating element diameter, distance from the furnace wall, and element quantity on temperature uniformity through orthogonal experiments. The results demonstrate that the number of heating elements has the most significant impact on temperature uniformity, followed by the distance from the furnace wall, while the diameter of heating elements exhibits a negligible influence. The optimized parameters are determined as follows: heating element diameter of 36 mm, distance from furnace wall of 65 mm, quantity of 10 heating elements, and inter-element spacing of 150 mm. Compared to that of the original design configuration, the optimized maximum temperature difference between workpieces is reduced by 44.0 ℃, corresponding to a 36.25% improvement. The results of our work may provide a technical reference for the design and optimization of heating elements in vacuum sintering furnaces.

In order to solve the problems of DBC substrate oxidation, rapid temperature rise and fall of homogenization, and continuous production, a continuous IGBT vacuum welding equipment was designed in this paper. The system has a long-term use temperature of 400 ℃, a working vacuum degree of 1 mbar, and an ultimate vacuum degree of 0.1 mbar. The logic of the continuous operation of the equipment was introduced in detail. The IGBT chip passed through the import platform, preheating chamber, welding cavity, cooling cavity and outlet platform on the carrier in turn. The formic acid was used as the reducing agent, and the vacuum welding process of the IGBT chip was completed by controlling the temperature, pressure and other parameters of the vacuum welding process. The design included the equipment layout, action logic, reaction chamber, vacuum system, gas circuit system, other mechanical systems, and electrical system. After the assembly and commissioning of the equipment was completed, the test was carried out according to the vacuum welding process of the IGBT chip. Its void rate is <1%, and the performance of the equipment meets the requirements of the vehicle specification level.

As a kind of special motor, vacuum motor is widely used in aerospace, semiconductor, scientific instrument, large scientific device and other fields. The requirements for transmission components vary with different application scenarios, such as volatiles, outgassing, heat dissipation characteristics, and the radiation resistance of materials. The vacuum motor includes stator, rotor, cable and bearing, etc. The material is complex and diverse, and the outgassing characteristic has great influence on the stability of the vacuum system. Different models with excellent vacuum performance were selected from domestic vacuum motors, and the vacuum and outgassing characteristics of the motors were tested and analyzed based on the theory of orifice conductance method. The vacuum comparison test was carried out simultaneously. By setting up a vacuum test system and combining with QMS, the vacuum degree characteristic, as well as the outgassing rate, gas composition and time evolution of vacuum motor under static conditions were tested experimentally. After 20 minutes without baking, the optimal vacuum degree of the domestic vacuum motor can reach 2×10^-4 Pa. After 10 hours without baking, the partial pressure of H₂O is 1×10^-6 Pa and that of C_xH_y is 1×10^-8 Pa. The work may provide a reference for related outgassing rate test, domestic vacuum motor selection, technology optimization and quality improvement, as well as domestic substitution.

Due to the nonlinear and time-varying characteristics of traditional freeze-drying machine vacuum systems, conventional PID control algorithms cannot meet the requirements for high-precision vacuum control. To improve the vacuum control performance of the freeze-drying machine, its vacuum system was optimized and designed using an intelligent optimized fuzzy PID controller. The input domain of the fuzzy controller was optimized and adjusted through the ABC algorithm. Meanwhile, the output of the controller was corrected based on the characteristics of the valve-controlled vacuum, effectively suppressing the nonlinear and time-varying effects of the system and improving the dynamic performance of the vacuum control. The actual testing data show that the vacuum control performance of the freeze-drying machine with the new system is better than that of conventional PID and fuzzy PID control systems in terms of adjustment time, overshoot, and steady-state error. This intelligent vacuum control system can effectively improve the control capability of the vacuum inside the freeze-drying machine during the freeze-drying process, thereby ensuring the accurate and smooth completion of the freeze-drying process.

This paper proposes a single-mode optical fiber transceiver(SMF transceiver) based on wavelength division multiplexing(WDM), designed to replace the traditional multi-mode optical fiber transceiver(SMF transceiver) in the multi-power supply control system for vacuum coating. Through experiments comparing the rise/fall time and transmission delays of the two transceivers for 20 kHz, 250 kHz,and 1 MHz signals, it is proved that the SMF transceiver control scheme can achieve equivalent or superior timing performance (e.g., an 85% reduction in rise time at 20 kHz) while reducing fiber usage by 50%. Scalability analysis demonstrates that using the SMF transceiver decreases the number of fiber links from 2N to N, which effectively addresses cabling and maintenance challenges in large-scale deployments. Cost analysis indicates that the use of SMF transceiver control solutions can reduce the total cost of ownership by about 33%. However their sensitivity to wavelength accuracy and temperature stability requires、 consideration in engineering design.

Aiming at the problem that single vacuum helium mass spectrometry (HMS) leak detection of ultrahigh vacuum (UHV) sealing device is susceptible to the uneven helium distribution, this paper proposes a method based on the optimal linear unbiased estimation algorithm for the detection of UHV sealing device faults. A vacuum HMS leak detector is designed and calibrated for the lowest detectable leak rate. The leak rate of the UHV sealing device was measured by the calibrated leak detector, and the optimal linear unbiased estimation algorithm was combined to integrate the leak rates measured by the leak detector at different moments with different helium distribution concentrations, to get the cumulative leak rate results with the lowest variance, and then to realize the detection of device leakage faults. The results of this method showed that the leakage rates of the UHV interlayer of two tanks, C3 and C6, were 2.16×10^-12 and 1.31×10^-12 Pa·m³/s, respectively, which exceed the leakage rate limit of ≤10^-12 Pa·m³/s, indicating that there were leakage failures in both tanks, and the leakage failure of C3 was more serious; the average relative error of the leakage detection results was only 0.05%, and the leakage failure of C3 was more serious. The average relative error of the leakage rate detection result of this method was only 0.054, and there was no obvious fluctuation, and the detection result was consistent with the actual situation. This method significantly improves the precision and reliability of small leakage detection, and provides highly reliable technical support for the performance evaluation and maintenance of UHV sealing devices.