In the process of vacuuming a chamber with water inside, the moisture content of the air increases sharply due to the rapid evaporation of the water under low pressure. The thin air with excessive moisture content enters the vacuum pump and precipitates a large amount of condensate during the pressurization process, which may cause the emulsification of lubricating oil and damage the vacuum pump. Therefore, it is crucial to study the evaporation characteristics of the water and the characteristics of air temperature and humidity changes during the vacuuming process. In this paper, a small vacuum test bench was established, and the changes of air temperature and humidity during the vacuuming process under different pumping flow rates and water surface areas were studied. It was found that the changes of air temperature are mainly affected by the pumping flow rate, and the changes of air moisture content are mainly affected by the water evaporation area. Then, a mathematical model of air heat and moisture transfer in the vacuuming process was established by comprehensively using the correlation formula of mass conservation, energy conservation and mild evaporation, and considering the influence of heat leakage gas leakage, and the accuracy of the model was verified by experimental results. The model was finally used to predict the variation law of air temperature and humidity under different initial temperature and relative humidity of air during vacuuming process in a practical project, and the dynamic refrigeration capacity was obtained.

As the integrated circuit process evolves towards 7 nm and below nodes, the wafer heating plate needs to achieve a highly uniform thermal field in vacuum environment. This article proposes an optimized arrangement method for heating elements based on the diameter/thickness ratio (K=D/δ) to address the problem of temperature uniformity caused by low thermal conductivity of stainless steel heating plates in vacuum equipment. By establishing a heat conduction radiation coupling model and combining it with finite element simulation, 120 sets of thermal field data were obtained for four typical diameters (6,8,10,12 inches) of heating plates in the thickness range of 10-30 mm. A model was established for the ratio of diameter/thickness and the optimal number of coil arrangements, and a relationship formula was fitted. The calculation results show that the residual R² of the model fitting relationship is 0.969 1. The results show that the temperature uniformity of the heating plate improves first and then deteriorates with the increase of the diameter to thickness ratio. The optimal diameter/thickness ratio is 8-12, corresponding to the optimal number of heating wire arrangement turns of 4-6. This model can provide quantitative reference for the design of stainless steel heating plates with a diameter ≤350 mm, significantly shortening the development cycle compared to traditional iterative trial and error methods.

To expand the application of graphite/copper composites in accelerators, powder metallurgy technology was used to prepare different doped graphite/copper composites. The effects of graphite content and doping elements on the relative density and outgassing rate of the composites were studied. The possibility of their application in beam collimators was evaluated. The results show that the relative density of undoped graphite/copper and nickel-coated flake graphite/copper composites is higher than 95%, while the relative density of other doped composites decreases with the increase of graphite content. The nickel-coated flake graphite/copper composites with graphite content of 30% show the lowest outgassing rate. A bake-out procedure can effectively reduce the degassing rate of composite materials. By combining an optimised fabrication route with a stringent bake-out protocol, the outgassing rate can be suppressed sufficiently to qualify Gr/Cu composites as collimator materials for the China Spallation Neutron Source accelerator.

Helium leak detection equipment plays a crucial role in industrial production by identifying minor leaks, thereby ensuring the safety and reliability of systems. However, the complexity of the equipment and the variability of the operating environment pose significant challenges for fault diagnosis. This paper presents a novel fault diagnosis method for helium leak detection equipment based on neural networks, with the aim of enhancing the accuracy and efficiency of fault detection. The methodology involves several key steps. First, operational data from the equipment is collected and preprocessed. The data is then fed into a convolutional neural network (CNN) to extract meaningful feature vectors and reduce dimensionality. Subsequently, the extracted features are input into a recurrent neural network (RNN) to capture temporal dependencies. Finally, the fault classification results are generated using an appropriate activation function. The experimental results show that the proposed CNN-RNN model achieves excellent diagnostic performance across various fault types, with classification accuracy and recall exceeding 99% on the test set, which is significantly outperforming traditional methods. Furthermore, the optimization strategies were explored, such as hyperparameter tuning and model architecture selection, to further improve the model's accuracy and generalization capability.

To enhance the perception accuracy and early identification capability of vacuum degradation in high-voltage vacuum circuit breakers, this paper proposes a vacuum monitoring technique based on multi-source data fusion and support vector machine (SVM) modeling. A comprehensive multi-source data acquisition system is developed, incorporating electrical signals, mechanical characteristics, and thermal parameters, to enable holistic perception of the circuit breaker’s operating status. Feature extraction and information fusion are performed using methods such as normalization, noise suppression, and principal component analysis, thereby constructing a high-dimensional feature space to improve the sensitivity to vacuum level changes. An SVM model is then employed to intelligently classify vacuum states and assess degradation trends. The results demonstrate that the proposed method outperforms traditional vacuum detection techniques in terms of recognition accuracy, generalization ability, and real-time responsiveness.

Multi rare-earth oxide doping is used to improve the comprehensive performance of traditional YSZ thermal barrier coatings, Sc₂O₃-Y₂O₃-ZrO₂ (ScYSZ system) ceramic materials with different Sc₂O₃ and Y₂O₃ ratios (total molar fraction of 8mol.%) were synthesized by the solid-state method. The microstructure and room temperature mechanical properties of ceramic samples were tested and analyzed, compared with the traditional 8YSZ ceramic material. The results show that the ScYSZ ceramics prepared by the solid-state method are composed of t' (the main phase) and c phases, and the proportion of t' phase increases with the Sc₂O₃ content. The fracture surface of ScYSZ ceramics is smooth, and the doping of Sc₂O₃ does not change the brittle fracture characteristics of YSZ materials. When the Sc₂O₃ molar fraction is ≥ 7.3%, the hardness of the ScYSZ system is about 4%-6% higher than that of 8YSZ, and it exhibits good comprehensive mechanical properties at room temperature. ScYSZ ceramics can be used as a potential ceramic material for thermal barrier coating.

Flexible thermal control coatings are applied to the outer surface of spacecraft to control the thermal balance of the spacecraft surface based on their own thermo-physical properties. During the magnetron sputtering process, process instability often leads to various defects in the coating, which in turn affects the coating quality. Traditional magnetron sputtering coating defect detection requires shutdown for inspection, which is inefficient and does not respond in a timely manner. This paper proposes a deep learning algorithm for image detection driven by a multi-dimensional attention mechanism, constructing a correlation mapping model between monitoring data, detection image sensitive features, and coating defects, to achieve efficient and high-accuracy intelligent identification. The experimental verification shows that the model recognition accuracy for cracks, electric sparks, and underplating defects is above 96%, laying a solid foundation for the online detection of flexible thermal control coatings on spacecrafts.

In order to explore a low-toxicity buffer layer material to replace the CdS buffer layer commonly used in Cu（In,Ga）Se₂ （CIGS） solar cells, magnetron sputtering technology was used to prepare thin film materials based on In₂Se₃ targets. The effects of pure sputtering, oxygen-doped sputtering and post-annealing treatment on the stoichiometric ratio, band gap and transmittance characteristics of the films were systematically studied. The results show that the transmittance of In₂Se₃ films prepared by sputtering is very low. Although the transmittance of the films can be improved by sputtering doped with oxygen, the stoichiometric ratio of the films will be greatly affected. The effect of post-annealing treatment on the properties of the films is negligible. The performance of In₂Se₃ thin films prepared by magnetron sputtering technology is still difficult to meet the application requirements of buffer layer materials.

Based on the strict requirements of ion implanter for pumping performance and safety protection of cryopump, the main performance index, mechanical structure and electrical system characteristics, application configuration, and unique safety purge sequence of cryopump for ion implantation were introduced. Compared with the cryopump for PVD, the cryopump for ion implantation has a larger diameter and higher requirements for hydrogen pumping speed and capacity. The hydrogen pumping speed and capacity are optimized by the structure design of cold plate and adsorption array. The control system of cryopump for ion implantation has a power switching unit and a backup battery module, and the unique safe purging process ensures that hydrogen can be safely discharged and reduces the risk of explosion.

G-M refrigerators use helium as the refrigeration working medium, and adiabatic degassing refrigeration is carried out by Simon expansion, which is widely used in superconducting magnet cooling, helium liquefaction, cryogenic pumps and cryostats. As an important part of the GM refrigerator system, the helium compressor provides power for the helium circulation in the GM refrigerator system. The compressor compresses helium to ensure that it flows through the system in a high pressure and pure state, meeting the needs of GM chillers for circulating working medium. According to the differences in cooling methods, helium compressors are divided into water-cooled and air-cooled types. This paper mainly introduces the design requirements and methods of air-cooled helium compressors, and completes the performance test of the whole machine to verify the rationality and effectiveness of the design.

To improve the thermal insulation performance and temperature uniformity of vacuum sintering furnace, the thermal insulation layer parameters were optimized using the theoretical model of heat transfer. The ANSYS steady-state thermal analysis method was used to study the effects of graphite plate thickness, carbon felt thickness, and the distance between the thermal insulation layer and the heating element on the thermal insulation performance and temperature field of the vacuum furnace. The results show that, 150 mm-thick carbon felt can largely improve the thermal insulation performance and temperature uniformity, but such improvement is little with further increasing the felt thickness. When the distance between the thermal insulation layer and the heating element is 80 mm, the temperature on the inner side of the thermal insulation layer reaches as high as 1 008.5 ℃. Moreover, compared with the case of original 100 mm-distance, the number of uniform temperature points increases by 10.4%. The thickness of the graphite plate has little and negligible effect on the temperature field.

The Mn-containing secondary hardening ultra-high strength steel was prepared by vacuum induction melting. Hot compression experiments were conducted at temperatures of 1 000, 1 050, and 1 100 ℃ with strain rates of 0.01, 0.05, and 0.1 s^-¹, respectively. A strain-compensated constitutive equation was established based on true stress-true strain data using the strain compensation method. The prior austenite was reconstructed to investigate the effect of hot deformation parameters on quenched microstructures. The results indicate that the flow stress decreases with increasing deformation temperature, while increases with rising strain rate. The as-established strain-compensated Arrhenius constitutive model can effectively predict flow stress, with a correlation coefficient of 0.999 8 and an average relative error of 1.868 6%. The quenched martensite combinations under different deformation conditions exhibit better consistency with CPP combination characteristics. As the deformation temperature increases and strain rate decreases, the proportion of high-angle grain boundaries increases, and the average grain size of prior austenite enlarges.

Currently, large vacuum induction furnaces commonly use coil structure designs with magnetic yokes, but this traditional configuration may have technical redundancy in smaller capacity furnace types. First, this paper systematically discusses the necessity and optimization path of magnetic yoke configuration for vacuum induction furnaces. Then, based on technical research on mainstream products at home and abroad,the technical characteristics and limitations of the magnetic yoke structure in practical applications are summarized. Subsequently, the feasibility of further expanding the concept of non-magnetic yoke design is explored, and an innovative design scheme of 1 000 kg level non-magnetic yoke coil system is proposed. Finally, the application value of the non-magnetic yoke structure in the 1 000 kg vacuum induction furnace is evaluated from the dimensions of equipment cost, operating efficiency, and maintenance convenience, providing theoretical basis and practical guidance for technological upgrades in related fields.

A passivation method for high specific volume tantalum powder with a specific volume of 100 000 μF·V/g and above after high temperature heat treatment and the design of a strong cooling device were introduced. Through rapid cooling technology, the strong cooling device significantly improves the production efficiency of tantalum powder, and avoids potential pollution of tantalum powder by volatiles in the furnace, ensuring the purity of the product. In addition, a three-step passivation technology was proposed, including primary passivation, secondary passivation and final passivation. This method can effectively solve the problem of heat retention caused by the reaction of oxygen-containing gas with tantalum powder in the passivation process, avoid the high oxygen caused by the temperature rise of tantalum metal powder, realize the fully stable passivation of tantalum powder, shorten the processing time, and do not introduce additional pollution. It has high practical value.