The journal Vacuum (Shenyang) and the journal of Vacuum Science and Technology (USA) started publication in 1964, aim to provide an excellent platform for academic exchange in the vacuum sector and assist with faculty promotion. It has gradually become a noteworthy literature to guide scientific research and production, and is a major historical event in the field of vacuum. In this paper, by tracking the founder of the journal Vacuum, we systematically review a brief history of the journal and describe the process of its initial establishment in 1964. It is confirmed that the notion of starting a new journal for the vacuum field was first conceived by Prof. Nai-Heng Yang of the Northeastern University to meet the demands of teacher promotion and scholarly communication, who is the only strictly defined founder of the journal Vacuum. The glorious history of the journal Vacuum, as a microcosm of the development of the vacuum sector in China, has symbolized the spirit of motivated viewing, strove mightily, unyielding efforts and altruistic giving for a large cohort of old-timers in the vacuum field. Such spirit is a role model and has left a most precious treasure for many of us to follow.

As the core component of wearable devices, the flexible strain sensors play a particularly important role in various fields. However, the function of the existing sensor is limited by the traditional conductive layer structure. A large number of researchers have introduced the micro-nano structure of animals and plants in nature into the sensor to give it more excellent performance. In this paper, the research progress of bionic flexible strain sensor is reviewed from the aspects of functional layer structure, preparation method and bionic structure. Firstly, the conductive layer structure of flexible strain sensor and the method of improving durability are summarized. Secondly, the preparation methods of bionic flexible strain sensors are concluded. Finally, the bionic structure types of the sensor are discussed from three aspects: animals, plants and components. In order to improve the excellent electrical properties of the strain sensor while obtaining more similar biological functions to organisms, more efforts should be devoted to the development of production and preparation processes for more effective replication of animal and plant microstructures and the improvement of bionic types applied to strain sensors in the future.

The rare earth composite oxide of （Yb_0.1Gd_0.9）₂Zr₂O₇ （YbGdZrO） is a candidate material for novel thermal barrier coatings （TBCs）, which can be potentially applied in higher temperatures. Both of single-ceramic-layer YbGdZrO and double-ceramic-layer YbGdZrO/YSZ TBCs were directly fabricated on top of （Ni,Pt）Al bond coat surface via electron beam physical vapor deposition （EB-PVD）. The phase structure, chemical constituent, morphology and thermal cycling behavior of those TBCs were systematically investigated. The results show that the primary phase structure of the as-deposited YbGdZrO ceramic coating is single defective fluorite phase with co-existing of a small amount of Yb₂O₃. Compared with the single-ceramic-layer coating, each beam of columnar crystal clusters in the sample with double-ceramic-layer TBC is relatively slender, and obvious columnar gain gaps can be observed. The 1100 ℃ thermal cycling lifetime of double-ceramic-layer TBC is about 1.5 folds as that of single-ceramic-layer YbGdZrO coating. After long-term alternating thermal cycling, the transverse microcracks grow in the single-ceramic-layer YbGdZrO coating and extend to several microns above the interface of YbGdZrO/TGO layer, causing interfacial degradation and separation. Moreover, the Yb element contained in single-ceramic-layer has inwardly diffused into the TGO layer. Longitudinal cracks appear within the double-ceramic-layer coating, while both of YbGdZrO/YSZ and YSZ/TGO interfaces remain basically intact. After thermal cycling failure, transverse and vertical microcracks are formed in the TGO layer of the single-ceramic-layer and double-ceramic-layer specimens, and even further induce the phenomenon of intra-layer fracture separation.

In order to improve the deicing efficiency for transparent conductive film on the surface of circular optical window during heating, through theoretical analysis of the Ohm's law and heat conductive effect, a theoretical model of heating efficiency of transparent conductive film on the surface of circular optical window was established. Based on the numerical simulation of the theoretical model, the deicing efficiency of the circular optical window with a diameter of 100 mm for 10 mm thick ice sheet at -55 ℃ was calculated. The experimental verification was carried out by heating with a 24 V DC power supply. The results show that there is a deviation between the deicing time of the experimental results and the theoretical calculation. The main reason is that in the process of deicing, in addition to most of the heat generated by the optical window surface, a small part of the heat is consumed by heat conduction and heat dissipation, and in the actual process of heating and deicing, part of the water on the window surface is heated and absorbs heat, resulting in increased energy consumption. Based on the experimental results and theoretical analysis, further measures to improve the efficiency of heating deicing are proposed.

Due to the unique advantages such as wide working pressure range with high pumping speed, ability to remove water vapor and solid particle, and stable performance, dry twin-screw vacuum pumps have been widely used in popular industries such as semiconductors, petrochemicals, and photovoltaic new energy. They have broad market prospects and have attracted widespread attention. This article comprehensively summarizes the recent theoretical research progress of dry twin-screw vacuum pumps from the perspectives of screw rotor end profile design, variable pitch and profile internal compression design, dynamic balance design, computational fluid dynamics and thermodynamic performance analysis based on recent research papers and patents. This review can provide reference for research in the field of screw vacuum pumps.

A design method for the three-blade linear arc rotor profile of Roots vacuum pump was proposed, the profile equation and the main structural parameters of the ZJ-5000 Roots vacuum pump rotor profile were given. The finite element analysis of the new Roots vacuum pump was carried out, and the volume flow rate under different inlet pressure was studied. Based on the new rotor profile, the actual product was produced, and the pumping speed and other performance indexes of Roots pumps with three-blade linear arc profile rotor and double-blade rotor were compared. The results show that the new three-blade linear arc profile has the characteristics of high volumetric efficiency, smooth curve, easy processing, accurate positioning and low working noise. Compared with the two blade rotor, the new one can withstand greater pressure difference load, and the pumping efficiency is improved compared with the traditional three-blade rotor.

The lunar environment simulation facility can simulate the temperature, vacuum, lunar dust and other environmental factors on the lunar surface in order to carry out relevant science research and test verification on the ground. In this paper, the current development status of lunar environment simulation facility is tracked and studied, and the key technologies for the development of lunar environment simulation equipment are sorted out in combination with the development and use of lunar environment simulation facility at home and abroad. Moreover, the development suggestions are proposed for the lunar environment simulation facility required for manned lunar exploration activities in the future.

The power of the CSNS II accelerator beam is upgraded from 100 kW to 500 kW, requiring that the average beam power of the linear accelerator to be increased from 5 kW to 25 kW, and the pulsed beam current to be increased from 12.5 mA to greater than 40 mA. This inevitably leads to an increase in the pressure of the room-temperature cavities. The differential pumping system, as a crucial matching unit between the room-temperature and superconducting segments, can significantly reduce the pressure distribution in this range, and reduce the residual gas components at the end of the LEDP to effectively avoid the impact on the performance of the superconducting cavities from gas sources in the room-temperature cavities. Currently, the dynamic pressure at the end of the linear section (DTL cavity) is approximately 2.0×10^-6 Pa, while the low-energy differential pumping systems (LEDP) and high-energy differential pumping systems (HEDP) at the front and rear of CSNS II superconducting cavities, both require a dynamic pressure of ≤5.0×10^-8 Pa. This paper presented a systematic design of the vacuum systems for LEDP and HEDP, and simulation and experimental verification were carried out. The findings show that the experimental results are in basic agreement with the simulation results. The combination of ion pump and NEG pump can meet the vacuum requirements of LEDP and HEDP, and effectively reduce the residual gas composition at the end of LEDP.

To meet the needs of high-frequency, miniaturized vacuum microwave devices, and find suitable cathode materials and laser systems, a strategy to develop new type of Cs3Sb cathode was studied. A tungsten sponge diffusion barrier layer was used as the evaporation source of the emission material, instead of the traditional nickel tube heating method. In order to enhance the adsorption capacity and light absorption rate of the cathode, the surface of the cathode substrate was modified by nanoparticle thin film coating and ion beam surface modification. The photoemission characteristics of the photocathodes before and after surface modification of the photocathode were studied. The results show that the photoemission quantum efficiency increases greatly after modification. It is believed through analysis that the main cause for the increase in quantum efficiency is the enhancement of light absorptivity and the increase in emission surface area.

A field emission low pressure gas sensing technique based on gas adsorption effects was developed. In this work, CNTs were grown directly on Ni alloy substrates by thermal chemical vapor deposition (CVD) method, ZnO nanorodes were prepared by the hydrothermal method, and the Al-N co-doped ZnO nanorodes were further synthesized by CVD. Then the field emission and low pressure N₂ sensing performances were investigated for CNT and ZnO nanorode field emitters. The results show that CNT emitters present good field emission performance with the turn-on field of 1.99 V/μm, while ZnO emitters show higher turn-on field of 14.9 V/μm. With the doping of Al-N elements, the field emission performance is improved significantly with the turn-on field of 8.9 V/μm. In the pressure range of 10^-4-10^-7 Pa, the CNT cathodes demonstrate best sensing behavior, and the sensing current rises up to 350％ within 5 min test under N₂ pressure of 10^-4 Pa. The pristine ZnO emitters show almost no sensing effect, but Al-N co-doped ZnO emitters display decent sensing behavior, indicating that Al-N doping effectively improves the gas sensing performance resulting from the addition of active sites on the ZnO emitter.

Based on the requirement of the spectral satellite, Lanzhou Institute of Physics symmetrically analyzed the demands of the Chang Guang Satellite Company and proposed the 25 W pulsed plasma propulsion system as the choice. Then a flight prototype was developed and number of ground tests were performed. The results showed that all of the parameters are adequate for the needs. To verify the environment adaptability, its compatibility with spacecraft, in-flight tests, and the difference in performance between in-orbit and ground, the LPPT-25 electric propulsion system was launched on the GP-1 satellite and officially verified on-orbit. The in-flight tests of the system were evaluated. The results show that the pulsed plasma propulsion system was normally operated and its operating parameters fit well with the ones designed, where the thrust was stably provided, and the telemetry temperature was adapted to the ranges controlled. The thrust of the electric propulsion is calibrated to be 306.3 μN, and compared with the ground test of 300 μN, the deviation between them is within 5%, which reflects a commendable consistency of the orbit-ground results.

Aiming at the design of C-C integrated composite grid module of LIPS-100 ion thruster, the thermodynamic characteristics of the grid were studied by using the thermal characteristics calculation model. Using Workbench transient thermal analysis method, the thermal performance parameters of two kinds of C-C gates with different curved surface orientation were analyzed, and compared with the traditional metal molybdenum gate. The results show that under the conditions of equal working conditions, equal spherical configuration and equal gate spacing, the weight of C-C composite gate is reduced by 35.7%, the upper limit of thermal analysis temperature is reduced by 19.6%, and the heating rate is reduced by 21.3%. Compared with molybdenum grid, the displacement of C-C composite screen grid is reduced by 0.151 mm, and the displacement of acceleration gate is reduced by 0.123 mm. The C-C composite screen grid has higher thermal shock resistance and can effectively alleviate the problem of gate spacing fluctuation in the early stage of thruster operation. Under the same composite gate material, when the spherical orientation structure is different, the grid center-edge thermal micro-displacement is different, the acceleration gate micro-displacement of convex gate is reduced by 0.025-0.038 mm compared to that of the concave gate, which can effectively improve the wear life of the acceleration gate zone. For small size ion thruster, convex grid has obvious advantages in thermal shock resistance.

The study of mineral samples is the basis of mineralogy, petrology, mineral deposit and other geological disciplines. The surface morphology, element composition and distribution characteristics of minerals can reveal the source of ore-forming materials, ore-forming process and geological history. This paper describes the principle, technical advantages and vacuum condition of TOF-SIMS, which has wide application potential for mineral sample characterization, focuses on summarizing the research progress and existing problems of the application of TOF-SIMS by domestic and foreign scholars in mineral identification, mineral imaging, quantitative analysis and in-depth analysis of mineral composition and mineral processing, and makes prospects in related fields.