The pressure within capsule need to be regulated and controlled by the pressure control system outside the vessel in the process of thermal vacuum test for spacecraft with capsule. Generally, the capsule is connected with the pressure control system via pressure -controlled pipeline (metal bellows). Any leak in the joint of the pressure -controlled pipeline and capsule would make the thermal vacuum test for spacecraft impossible, hence it is of great importance to ensure that the leak rate of joint meet the test requirements. This thesis, studying the specific structure of joint, achieves the leak detection method of the joint, which is verified by test and acquires good effect.

The vacuum leak detection is an important technology to obtain high vacuum in the drift tube linear accelerator (DTL). The quadrupole mass spectrometer is an important tool for analyzing the components of the residual gas in the vacuum system, and can also be used as a means of leak detection. In this paper, the DTL1^# cavity was detected by two means of helium mass spectrometer leak detector and quadrupole mass spectrometer. When the coil of the 12^# drift tube was applied current, the pressure, leakage rate and residual gas composition of the cavity were all changed, and the spectral peak of water increased most significantly. So there's something wrong with 12^# drift tube. The cavity quickly obtained the high vacuum of 10^-6 Pa by proper treatment, which met the requirements of the linear accelerator for vacuum system.

In view of the disadvantages of large size and low efficiency of traditional DC high voltage generators, this paper designed a 200kV DC high voltage generator with a continuously adjustable output power of 400W. The focus is on the power and control part of the DC high -voltage generator, in which the power part was chosen to use the high -frequency inverter technology and high-frequency transformer with voltage doubler rectifier. The DSP was used for the control part as the system control core. Simulation results and theoretical analysis confirm the correctness and feasibility of the system design scheme.

The acceleration power supply is an important part of high energy ion implantation system and provides energy for ion acceleration. According to the parameter requirements of new type high energy ion implantation system with adjustable voltage from 10kV to 100kV and the ion beam current strength less than 20mA, an acceleration power supply was designed based on DSP to improve the traditional acceleration power supply structure. This paper discussed the main circuit structure of the power supply including three-phase rectifier, buck chopper voltage regulation, full bridge inverter, transformer booster, voltage doubling rectifying circuit and it's simulation analysis.

During the vacuum leak detection testing of standalone product for single-O-Ring seal model, the leakage rate curve demonstrates continuous and tardy up-trend. Moreover, sharp corner phenomenon appears that is similar to the typical doubledeck elastic seal. It is essential to thoroughly study this issue for subsequent leak detection, as this issue has impact on the reliability of testing results. In this paper, the reason was located theoretically, by establishing the mathematical model to simulate the leakage process of double seal structure. Besides, the working sets has been designed and the experimental results were analyzed adequately. These researches may have guiding significance for the leak detection testing in the future.

One of the key tasks of China's lunar exploration phase three project is to collect lunar sample and return to earth under the condition of unmanned state, and to maintain the original state of the lunar sample, and to ensure the accuracy of the ground data analysis. Aiming at the characteristics of the mission for the lunar sampling in China, and by referring to the successful experience abroad, this paper designs a sealing structure and locking mechanism to automatically seal the lunar sample. The design can realize the vacuum seal with extremely low leakage rate of the lunar sample, and can still maintain the leakage rate of the sample container after withstanding some mechanical environment conditions. The ground test verification indicate that the design can meet the expected target and the needs of lunar sampling mission in China.

The principle and characteristics, current application status and equipment of vacuum conveying technology were summarized in this article. The future development trend and prospect of vacuum conveying technology were also analyzed and discussed. It may be helpful for the development of vacuum industry.

With the rapid development of superconducting technology, more and more attention has been paid to the refrigeration system that provides cryogenic environment for superconducting materials. This paper introduces a sub -cooled nitrogen cooling system for HTS motor based on the principle of decompression and cooling. It includes the technical specifications and related requirements, the overall structure, key technologies, thermal load analysis and calculation, etc. The system adopts vacuum cooling to obtain sub-cooled liquid nitrogen and coil wires in the cooling motors. Liquid nitrogen inlet and outlet temperatures are 68K and 72K, respectively. The utility model is mainly composed of a liquid supply dewar, a sub-cooled box, an evacuation pump, a superconducting coil dewar, a reflux dewar, a low temperature pipeline and a temperature meter. The experiment indicates that the cooling system is reasonable in design and easy to operate, and the loading operation of the superconducting motor is successfully realized.

This paper analyses the problems existing in the vacuum system in the thermal power plant and introduces the energy saving transformation of the vacuum system. It is considered that the application of the steam ejector in the vacuum system of the condenser is an effective means to solve the problem of the vacuum system in the thermal power plant. The effect of the energy saving transformation of the vacuum system is analyzed by detailed data comparison. Finally, some suggestions are put forward on the energy saving transformation of the vacuum system.

The low-temperature adsorption bed is an crucial part for the pressure recovery system of the chemical laser. In order to reduce the weight of its shell, this paper uses the finite element analysis method to explore the design method and optimization scheme to make adsorption bed shell and lid with low-temperature aluminum alloy material instead of stainless steel. The results show that the strength and vacuum condition of the aluminum alloy material adsorption bed have both met the design specifications, opening a new approach to design the low-temperature adsorption bed for the use of lightweight material.

Computational fluid dynamics and theoretical fluid dynamics, experimental fluid dynamics together constitute the fluid mechanics research field. With the development of computer science and technology, and the progress of mathematical theory and numerical method, computational fluid dynamics (CFD) is gaining more and more attention by researchers and engineering technicians. The prediction accuracy of CFD theoretical model is widely recognized, and CFD has become a research tool for complex flow and heat transfer problems, and an important design tool used in engineering fields and teaching tool of thermal fluid mechanics. CFD method has applied in vacuum engineering as a research tool to investigate the working mechanism of vacuum equipment. Numerical study of inner flow behavior in a steam-jet vacuum pump was carried out, the simulation results was analyzed to reveal the effect on the pumping performance by CFD approach, which can be used to optimize the structure and improve performance of the steam-jet pump.

Arc ion plating is one of the most commonly used technique in vacuum film depsition technology, a long -term development in the fields of scientific research and industrial production have been obtained in present. However, the effects of some process parameters including arc current, deposition pressure, deposition temperature, etc. on film structure and properties were often scattered in different literatures during film deposition, being not conducive to the deep understanding of these parameters. This present paper reviews the role of the process parameters including arc current, deposition pressure, target - substrate distance, substrate bias, deposition temperature and external magnetic field, etc. It can be deeply recognized for the roles of these parameters on film structure and properties, through the summary of these process parameters during film deposition, which promotes the process development and progress of vacuum film deposition technology.

The cleaning method of steel tube in the pretreatment of coating was studied. The steel tube was cleaned by multiple ultrasonic cleaning modes, then dried naturally, cured at high temperature, and the pretreatment quality of the steel tube coating was analyzed. The test results show that the stainless steel pipe after precision polishing adopts the solvent ultrasonic cleaning + tap water ultrasonic cleaning + deionized water ultrasonic cleaning + deionized water washing + drying process is feasible and can meet the requirements of the subsequent coating process for future realization. The production automation process operation improves the test basis.

Micro -nano structured Al -doped ZnO thin films were deposited by DC -RF coupled magnetron sputtering system binding winding bar scraping coating on glass substrates at room temperature. The RF sputtering power ratio of basement AZO film was adjusted from 50% to 90% . The structure, surface morphology, optical and electrical properties of the micro -nano structured AZO films were investigated by X-ray diffractometer, scanning electronic microscope, Hall effect test system, ultravioletvisible spectrophotometer and WGW, respectively. The results indicate that the resistivity of the micro-nano structured AZO film is dominated by RF sputtering power ratio of the basement AZO film. The films deposited under RF sputtering power ratio of 80% exhibit the lowest resistivity of  5.32×10^-4 Ω·cm. The average optical haze is approximately 36.3% in the visible wavelength. With the increase of RF sputtering power ratio, the surface morphology, growth form and the particle size of the films change greatly. Meanwhile, the micro-nano structured AZO films show light trapping effect and excellent optical and electrical properties.

Radio frequency magnetron sputtering was used to deposit Mg doped Gallium oxide(Ga₂O₃) thin films with different Mg concentrations by alternate sputtering of Ga₂O₃ and MgO targets. The results showed that with the increase of Mg concentration, the crystallinity of the films decreased and the thickness of the films reduced; the light transmittance had no obvious change, but the band gap increased gradually, so we can change the band gap width of Ga2O3 film continuously by doping Mg into Ga2O3 film rangeing from 4.96 eV to 5.21eV; The PL spectroscopy results show that the doping of Mg leads to a blue shift of the PL peak, and a new luminescence peak appears near the 473 nm blue light.

With the development of carbon composite materials, the temperature of graphitization is getting higher and higher, while the external dimensions of the workpiece are getting bigger and larger. The requirements for the high temperature graphitization furnace are thus put forward. In this paper, the power calculation of large size graphitization furnace with a resistance heating cylindrical heat preservation structure is introduced including the technological characteristics, structure type and the selection of calculation parameters.

In this paper, Tb thin film was deposited on the surface of sintered NdFeB magnets by the method of vacuum multiarc ion plating, and then a vacuum heat treatment was applied in the samples. Tb was introduced from the surface into the interior of the magnets by grain boundary diffusion (GBD), and the magnetic performance and heat resistance of the magnets was studied at last. The results show that after grain boundary diffusion treatment, the metal Tb enters the grain boundary within a certain depth range from the surface of the NdFeB magnet, resulting in the increasing of intrinsic coercivity of the magnets by 9000-10000Oe, and great reduction of high temperature hirr of the magnets. The intrinsic coercivity and heat resistance of the magnets were significantly improved.

The MoS₂ nano-precursor solution was synthesized by sodium molybdate and thiourea. The nano-powder was obtained by vacuum freeze-drying method under different freezing modes. The morphology and particle size of the nano-powder materials were studied by transmission electron microscope and atomic force microscopy instruments. The results show that the nanometer molybdenum disulfide prepared by vacuum freeze -drying method has a particle size of 25nm -37nm. At the same time, the nanometer molybdenum disulfide was added as an additive to the paraffin oil. The friction performance was measured by a fourball friction tester. The size and friction coefficient of the wear spot were both significantly reduced.