Vacuum packaging is a technology with wide applicability and large market demand. This article introduces the purpose and significance of vacuum packaging, explains the principles and selection methods of several types of vacuum packaging equipment, summarizes the application of vacuum packaging machine, and discusses its development trend.

The liquid helium cryogenic system(LHCS) is an auxiliary facility of HL-2M tokamak, which is being built in Southwestern Institute of Physics(SWIP), the demand of liquid helium from cryogenic users are 16m³ per week. So it's necessary to construct a helium recovery and purification system (HRPS), which consists of a recovery part, a storage part and a purification part. The recovery part mainly includes 2 piston compressors with capacity 50m³/h and 100m³/h respectively; the storage part mainly includes 4800m³ higher purity helium tanks, 1200m³ dirty helium tanks and 50m³ two gasbags; the purification system mainly includes a high pressure helium purification equipment, which can improve the helium purity from 95% to 99.999% or even more. The maximum recovery rate of the system is designed to 150m³/h.

UV radiation is one of the main factors that cause the degradation of non-metal materials on the external surface of satellites. The material must be sufficient evaluated for UV radiation effect before it can be used in space. Due to UV irradiation test acceleration factor can not be too large (near-UV does not allow more than 5 times), achieving the full life UV exposure dose of the material on-orbit through ground test will take too long time. In this paper, the degradation law and degradation mechanisms of typical spacecraft functional materials under UV irradiation are introduced. The modeling method of material degradation under UV irradiation are then proposed. This provides an effective mean to solve the evaluation of functional spacecraft material degradation under high dose UV radiation.

Two different specifications of diffusion pump oils were obtained by distillation cutting through petroleum base oil by using molecular distillation technology. The two kinds of diffusionion pump oils are then subjected to full-scale distillation, and the data obtained after cutting the two-stage and five-stage fractions. The experimental results show that the diffused pump oil fully distilled has a narrow distillation range, a smaller slope and a narrower distillation range. We found that the light fraction and heavy fraction contained in the diffusion pump oil are less, the mixed components are relatively uniform, and the ultimate vacuum is higher. After cutting two and five fractions, kinematic viscosity distribution is uniform, which indicates that the mixed components in the diffusion pump oil are uniformly distributed and the purity is higher.

Large vacuum containers are required in modern large science projects, but the design of large vacuum containers needs to consider various factors. It is an important scientific issue how to design large vacuum containers. We designed and analyzed a large-scale horizontal vacuum container in this paper. And the vacuum containers with an inner diameter of 5 m and a length of 6 m were designed, which had many large square flanges. The finite element analysis software, ANSYS-Workbench was used for the analysis, which obtained the stress and deformation distribution of vacuum container under the working condition. And then the structure was optimized and the stability was analyzed. The analysis results show that the design is reasonable and feasible.

Photo-stimulated-desorption is the synchrotron radiation beam line, which is different from the typical vacuum system. In the whole process of the Photo-stimulated-desorption, photoelectron and secondary electron play a major role in the excitation of adsorption gas on the surface of vacuum material.Theelectron-stimulating desorption equipment (ESD) is important in studying the electron-stimulating gaseswith different materials and processes. Through theoretical calculation and analysis based on the physical process of electron-stimulating desorption, this paper has developed an equipment for above-mentioned experiments in 400eV~1000eV electron energy, which provides the experimental basis for studying optimal processing and treatment process of material surface in vacuum.

Energy conservation in the modern sense is not simply to reduce energy use by means of reducing production efficiency and quality of life, but to improve energy efficiency and reduce energy consumption. From the point of view of structure, unit configuration, operation and application, the possibility of energy saving technology of mechanical vacuum pump is analyzed and studied. Practical exploration and experimental study are carried out. A new energy saving scheme and new ideas with practical value are thus put forward.

In this paper, the external surface condensation and partial icing problems of some vacuum multilayer insulation pipes in a launching site are analyzed in detail. Improving measures are then put forward, which may provide reference for future production of vacuum insulated pipes.

The experimental principle, device, sample preparation, test procedures and data processing of volumetric adsorption isotherm are introduced in detail. It was proved that the adsorption performance of 5A molecular sieve for CO₂, N₂ and H₂ was better than that of the 13X molecular sieve at liquid nitrogen temperature and low pressure. On the basis of analyzing the adsorption isotherms of 5A and 13X molecular sieves to CO₂, N₂ and H₂ at liquid nitrogen temperature and low pressure, the characteristics of adsorption isotherms of 5A and 13X molecular sieves at LNG and LH₂ temperatures were analyzed. The adsorption isotherms of 5A and 13X molecular sieve obtained under test at liquid nitrogen temperature and low pressure can provide good reference data for engineering design.

Electron Impact(EI) ion source is a core component for the miniaturized magnetic mass spectrometer, and its performance has a great impact on the mass resolution and sensitivity of the instrument. In this study, the structure of ion repeller electrode was optimized and the voltage driving method was improved to enhance the overall performance of the EI source. Three-dimensional model of the miniaturized EI source was constructed using the ion simulation software simion-8.0, and the simulation was focused on investigating the influence of geometric parameters, ion repeller shape and the electric parameters on the ion focusing performance and ion transfer efficiency. By simulating the trajectory of ions, the ion motion parameters were obtained. At the same time, the ion focusing effect and ion transfer efficiency of the EI source were analyzed using the phase space method. The theoretical simulation results show that the ion's position focusing radius was less than 0.08 mm and ion transfer efficiency of over 99% were achieved when S₁=1.2mm, S₂/S₁=1.6, S₃=2mm, ion repeller was arc shape and the ion focusing lens and the main slit were driven by the high voltage and constant voltage tracking method. The ion transfer efficiency and the ion focusing performance could be greatly improved when the ion repeller structure and the voltage driving method were improved. Furthermore, high ion focusing performance could be maintained during the whole mass range. The optimized EI source could greatly improve the sensitivity and mass resolution of miniaturized magnetic mass spectrometer. Although we only investigated the performance of geometric parameters and repeller structure and electric parameters by simulation, the achievements would be helpful and instructional for further experiments and study.

The 90kA/ 85V DC power supply of the first 1.5T vacuum condensing furnace in China is introduced. This work mainly focuses on the application background, system constitution, main circuit, principle of main unit of control circuit and monitoring system of upper computer. The practical effect and application prospect are discussed.

In this paper, we successfully developed a test method based on the L300 series helium mass spectrometry of LEYBOLD to test the total leakage rate of spacecraft used to a non-vacuum accumulative helium detection method. After many tests, the results show that the as-developed spacecraft total leakage rate test system has high measurement accuracy and stable performance. It not only reduces the total leakage rate of the spacecraft system to a minimum, but also reduces the weight of the equipment and increases the mobility. It has some engineering applications and popularization values.

A relative method for calibrating vacuum leak is to compare collection current of quadruple mass spectrometer. According to the known standard leakage rate, the leakage rate of vacuum leak can be calculated. Use the calibration device of vacuum and leak rate, it can conveniently calibrate the vacuum leak, makes the uncertainty conforming to the requirement of values transfer, and satisfy actual requirement. This paper mostly introduces the theory, process of relative method for calibrating vacuum leak and uncertainty assessment.

Carbon films were deposited on different substrates, such as silicon, high-speed steel and stainless steel, by magnetron sputtering. Keeping other parameters constant, the pulsed negative bias varying from 100 V to 400 V was applied to the substrate in order to investigate the change of micro-structure and performance of the carbon films. The results show that all the as-deposited carbon films are amorphous and hard with good surface quality. The hardness, thickness as well as deposition rate of the carbon films increase initially and then decrease with increasing pulsed bias, while the friction coefficient behaves oppositely. The optimized mechanical properties of the carbon films are obtained at the pulsed negative bias of 200 V.

This paper studied the cause and the improvement measures of common defects in Fe-Cr-Al alloy ingots smelted by 150kg VIM furnace. Through four experiments, the influence of pouring temperature, pouring time, the lining use times and whether the tundish used a filter are studied on the surface quality and the internal shrinkage. The results show that the surface quality of the ingot is better and there is no shrinkage cavity defect under the condition that the pouring temperature is 1640 ℃, the pouring time is 0.56 min, the lining is used less and the tundish uses the filter.