Most studies on ferroelectric thin films are focused on perovskite structural materials. However, these traditional ferroelectric materials have a variety of problems, such as poor compatibility with Si, environmental pollution caused by Pb, large physical thickness, low resistance, and small band gap. Different dopants such as Si, Zr, Al, Y, Gd, Sr and La can induce ferroelectric or antiferroelectric properties in HfO₂ films, resulting in residual polari stion up to 45 µC·cm^-2 and coercivity (1~2 MV·cm^-1) approximately one order of magnitude greater than that of conventional ferroelectric films. At the same time, the thickness of HfO₂ films can be very thin (below 10 nm) and the band gap is large (~ 5 eV). These advantages over traditional ferroelectric materials can overcome the obstacles of traditional ferroelectric materials including ferroelectric field effect transistors and 3D capacitors in thin film memory applications. In addition, the electrical and thermal coupling of antiferroelectric films holds promise for a variety of applications, such as energy harvesting/storage, solid state cooling, and infrared sensors. HfO₂ doped thin films can be deposited by different deposition techniques, such as ALD, sputtering and CSD, and ALD has more obvious advantages in film deposition. In this paper, the recent progress of ferroelectric and antiferroelectric properties in HfO₂ doped thin films is reviewed. The effects of different doping elements, film thickness, grain size, electrode, annealing, and stress on the ferroelectric properties of HfO₂ thin films are described in detail.

Firstly, the mainstream forms, technical characteristics, and current usage status of liquid metal cooling directional solidification/single crystal furnaces are introduced. Then the applications of Sn and Al as medium to LMC furnace are compared. Finally, the development prospects of Sn cooling and Al cooling directional solidification equipment are analyzed.

By controlling winding speed, cathode power, process pressure, linear ion source current, thickness of NiCr seed layer, roll to roll magnetron sputtering machine was used to deposit nano-copper film on the surface of organic film substrate, in order to improve electronic property of copper current collector. The sheet resistance of copper coating was characterized by four-probe method, and the influence of different process parameters on the sheet resistance of copper coating were obtained. The results show that with the increase of running speed of substrate, the sheet resistance increases quadratically, and with the increase of cathode power, the sheet resistance decreases in power. In the process pressure range of 0.13~0.45Pa, the sheet resistance reaches the minimum at 0.2Pa. With the ion source current increasing in the range of 0~0.7A, the sheet resistance decreases linearly. NiCr seed layer can improve the sheet resistance of copper layer, and the sheet resistance of copper coating with 6.7nm NiCr seed layer is 23.2% lower than that of copper coating without seed layer.

Copper(Cu) foils were deposited by high power impulse magnetron sputtering(HiPIMS) method. The effects of sputtering voltage on the microstructure and properties of the Cu foils were investigated. The results show that the Cu foils deposited with the sputtering voltages of 700-950V present (111) crystal preferred orientation obviously, their grain sizes are between 27.7nm and 36.5nm, and the relative densities are between 96.1% and 98.5%, which is distinctly superior to that of the Cu foils prepared by ordinary DC magnetron sputtering. With the increase of sputtering voltage, the Cu foil gradually changes from ductility to brittleness, and the resistivity gradually decreases to 2.38μΩ·cm, which is close to the solid-state resistivity of pure Cu.

Through-silicon-via is currently a very popular high-density packaging technology, but the metallization of deep silicon holes in silicon through-hole technology is a very difficult process issue, because conventional magnetron sputtering techniques are difficult to deposit seed layers such as copper and tungsten in high aspect ratio silicon holes. Through simulation and calculation of the relationship between the two-dimensional non centered collision angles of copper atoms during oblique sputtering, it was found that when there is energy loss in atomic collisions, the angle of copper atoms incident into the silicon hole changes, which helps to deposit at the depth of the silicon hole. In this paper, copper seed layers were deposited in silicon blind holes with different aspect ratios by using negative bias assisted confocal sputtering of multiple copper targets to verify the feasibility of this method, and the deposition of copper seed layers in silicon pores with a depth to width ratio of 8:1 was successfully achieved by three target co sputtering.

Since GaAs was first discovered to have a negative electron affinity in the 1960s, negative electron affinity(NEA)materials have been widely studied and used in photoelectron emission,secondary electron emission and cold cathode. Compared with conventional emitting materials, the conduction band minimum of bulk NEA materials is higher than their surface vacuum energy level, which makes it easier for electrons in the conduction band to be emitted from the surface into the vacuum, and therefore these materials are ideal for electron emission. This paper introduces the NEA materials from the definition, main material classification and applications in cold cathodes, and gives a conclusion of the bottleneck and future development direction of NEA material.

This paper introduces a set of high-precision measuring device for the outgassing rate of vacuum materials based on the method of switching between two pumping paths developed by the engineering machinery vacuum auxiliary laboratory of SSRF Ⅱ beamline project. Based on this method, the outgassing rate of common oxygen free copper material samples in the synchrotron radiation vacuum system was tested. The outgassing amount of the sample with background and the background in the conditions of different temperature, outgassing time,and after the gas path conversion was measured and caculated. The results show that the oxygen free copper outgassing rate is 3.06×10^-12Pa·m³·s^-1·cm^-2 after 72h baking at 150℃, it indicates that the device has a high test accuracy of outgassing rate which can meet the measurement requirements of synchrotron radiation device for the outgassing rate of ultra-high vacuum materials.

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.

As the most promising TiN film substitute material, TiAlN film has excellent properties such as high hardness, low friction coefficient, good high temperature stability and corrosion resistance. The TiAlN hard films are widely used in the fields petroleum, tools, molds, electric power and aircraft engines. The current application and research progress of domestic and foreign TiAlN films, the preparation methods, and the effects of process parameters on structure and properties of TiAlN films are summarized. The performance of TiAlN film is comprehensively introduced, the method to optimize the performance of TiAlN film is pointed out, and the research and application direction of TiAlN films are prospected. The TiAlN film will develop towards the multiple composite, multilayer structure, and nano multi-layer structure with the further research and the demand of application.

Transition metal nitride hard coatings are widely used for cutting tools, precision molds and mechanical parts. With the development of cutting technology and the increase of difficult-to-process materials, hard coatings have been continuously developed from traditional binary coatings to ternary coatings and quaternary coatings. The (Cr,Ti,Al)N quaternary coatings have attracted much attention because of their excellent comprehensive properties. Based on the basic principle and technical characteristics of magnetron sputtering deposition, this paper introduces the common magnetron sputtering deposition technology for the preparation of (Cr,Ti,Al)N coating, analyzes the effect of using elemental target and alloy target for deposition, and studies the influence of magnetron sputtering process parameters on the mechanical properties of (Cr,Ti,Al)N coating, and finally discusses the function and preparation method of (Cr,Ti,Al)N gradient coating. This paper may provide theoretical reference and guidance for designing the preparation process and improving the properties of (Cr,Ti,Al)N coating.

The gas tightness of envelope material is one of the important technicalities of aerostat products. In order to study the gas tightness of materials after processing, three materials with bearing layer made of Vectran, nylon and polyimide fabric were chosen as the research objects, and processing parameters here was consistent with the actual working conditions. The helium permeability of materials that were original, after being used and the joint position were tested. The variation of helium permeability was further analyzed. The research results show that the helium permeability of envelope material increases with the increase of kneading times and the area of sealing gap. Besides, the helium permeability of the gap containing the external hot strip is equivalent to that of the bulk material. This study could guide the choice of materials, the product processing and the assessment of overall leakage.

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.

The rare earth oxide ceramic designed as 4.5wt.%Gd₂O₃-5.5wt.%Yb₂O₃-10.5wt.%Y₂O₃-79.5wt.%ZrO₂ (GdYbYSZ) is a candidate material for thermal barrier coatings (TBCs), which will be suitable for application at higher temperatures. GdYbYSZ ceramic powders and bulks are fabricated by solid-state synthesis at temperatures above 1 300 ℃, and the powders have no phase transformation and exhibit excellent thermal stability despite long-term calcination at 1 100 ℃和1 300 ℃. The averaged thermal diffusivity and thermal conductivity of GdYbYSZ ceramics are approximately 2.1% and 5.1% lower than those of the conventional YSZ bulk respectively. The GdYbYSZ ceramic coatings are directly manufactured on the surface of (Ni, Pt)Al bond coat by means of electron beam physical vapor deposition (EB-PVD), whose phase structure consists primarily of cubic phase with co-existing of excess Y₂O₃ and ZrO₂. Meanwhile, elemental compositions of Y and Zr within as-deposited ceramic topcoats are higher than those in the ingot, and the constituents of Gd and Yb elements in these two types of specimens tend to be similar. A large number of regularly distributed “mud-like” microcracks appear on the surface of GdYbYSZ ceramic coating after the long-term alternating thermal cycling at 1 100 ℃. The transverse microcracks originating in the ceramic topcoat have elongated to the interface of ceramic coating and TGO layer that further cause the degeneration and separation of the interface. The spalling location of the GdYbYSZ ceramic coating mainly occurs at the upper and lower adjacent interfaces of the TGO layer. The serious rumpling, undulation, cross-linking, stress accumulation and rapid relaxation at the convex tip exist in the TGO layer are the critical factors to accelerating interfacial delamination and spallation failure of GdYbYSZ/(Ni, Pt)Al TBCs.

A layer of organic film was coated on the PET substrate with polyacrylate polyol resin, and an inorganic film was deposited on the organic coating by plasma enhanced atomic layer deposition(PE-ALD)to obtain functional PET composite film. The effects of organic coating thickness, PE-ALD coating type and PE-ALD coating temperature on the water vapor barrier property and light transmission property of PET composite films were investigated by water vapor transmittance tester and ultraviolet-visible-near-infrared spectrophotometer. The results show that the thickness of polyacrylate polyol organic coating film has little effect on the water vapor barrier property and light transmittance of the PET composite film.The Al₂O₃ film deposited by PE-ALD can greatly improve the water vapor barrier property of the PET composite film, and the water vapor barrier property is the best when the PE-ALD coating temperature is 100℃,reaching 0.17g·m^-2·d^-1.

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.

Recently, microarray-structured flexible pressure sensors have attracted extensive attention owing to their controllable shape, small size and high mechanical properties. In addition to the selection of advanced functional materials, the introduction of microarray structures for flexible pressure sensors under traditional working principles is important to further enhance the sensing performance of the device in terms of sensitivity and response time. In this paper, the materials, distribution of microarray, fabrication strategies and sensing characteristics are systematically reviewed. Firstly, the common materials used to fabricate microarray-structured flexible pressure sensors are summarized. Secondly, the different distribution types of the microarray structure are compared. The fabrication strategies are then compared and summarized in detail. Finally, the mechanisms of sensing characteristics of several common-used microarray-structured flexible pressure sensors are mainly discussed. In the future, the force-electric conversion mechanism of the sensor and the stability of the device under multiple environments should be further investigated in order to provide a theoretical basis for the development of flexible pressure sensors with ultra-high sensing performance.

The measurement of secondary electron emission coefficient is very important for the development of vacuum electronic devices. To measure the secondary electron emission coefficient of materials with low electrical conductivity, it is necessary to design a high performance electron gun with adjustable energy, beam spot diameter, deflection and pulse. According to the performance index of the electron gun, its electron emission, electron optical system and potential relationship are preliminarily designed. The pulse emission of electron beam was realized by applying pulse voltage to the control pole. The CST software was used to model and simulate the electron gun, the influence of focusing pole voltage on the beam spot size was obtained, and the effect of the deflector electrode was simulated. The results show that when the cathode voltage is -1000V, the control electrode voltage is -1005V, and the first anode voltage is -880V, as the focusing voltage increases from -400V to 1000V, the beam spot diameter increases from 0.2mm to 10mm, the relationship between them is almost directly proportional. The quadrupole electrostatic deflector is more suitable for use in the same space by comparing two deflection components. When the working distance is 30mm and the deflection voltage is 200V, the deflection sensitivity can reach 34mm/kV and the corresponding deflection angle is 12.8°. The design of the electron gun is reasonable and meets the requirements of the index, it can be used to measure the secondary electron launcher.

Cathodic arc is an important material source for a variety of film and coating preparation processes. From the cathode spot on the cathode surface, the generation (phase transition) and expansion (transport) of plasma in the vacuum chamber, to the final deposition on the biased substrate to form a coating or film, this series of links contain complex physical processes. Deeply analyzing and understanding of the processes and related mechanisms will undoubtedly play an important role in guiding the coating preparation process. This paper briefly introduces the process of the discharge phenomena and the history of the related coatings development. Then the cathode discharge mechanism and the plasma behaviors closely related to the coating process, such as plasma velocity, sheath, oblique incidence and attachment coefficient are discussed. The aim is to help readers form a clear physical image and context for the process of cathode arc and its coating formation, and serve to guide the practice of scientific research and production.

The electric propulsion technology is an important propulsion system technology for Chinese satellites in the future. It has the advantages of higher specific impulse, lower thrust and higher propellant utilization compared to the conventional chemical propulsion. The ion thrusters mainly use xenon as propellant. Helium is used as the leakage gas in the conventional sealing test of the propulsion system. There is a conversion relationship between the leakage detection result and the actual leakage rate of the xenon. In order to accurately evaluate the actual leakage state and leakage rate of the electric propulsion system, it is urgent to carry out relevant research. In this paper, the feasibility of xenon in-situ leak detection technology is verified by building a several tracer gases testing system. Through theoretical analysis and experimental research, the leak rate conversion relationship between xenon, helium and krypton, as well as the theoretical upper and lower limits of the conversion coefficient, are preliminarily obtained. It will provide a reference for the leak detection of the electric propulsion system.

Oxide thin film transistors(TFT) are the core driving components of active matrix organic light-emitting diodes, and are the key technology for developing new displays today. They have broad application prospects in flat panel displays. However, there are a large number of defect states in oxide semiconductors caused by oxygen vacancies, which destroy the performance and stability of TFT device, and become a bottleneck technical problem for its commercialization. Therefore, IZO TFT was prepared by RF-sputtering and treated with O₂ plasma to study the effects of O₂ plasma treatmert on IZO film and device performance and stability. The results show that after plasma treatment, the mobility of IZO TFT increases from 8.2cm²/（V·s） to 9.5cm²/（V·s）, the threshold voltage changes from -3.2V to -5.1V, the sub-threshold swing decreases from 0.45V/decade to 0.38V/decade, and the switch ratio changes from 2.3×10⁷ to 4.4×10⁷. Under negative light bias, the threshold voltage drift of the device reduces from 7.1V to 3.2V. The threshold voltage drift of the device decreases from 12.5V to 6.4V when aging at 100℃. O₂ plasma treatment can effectively improve the electrical performance and stability of IZO TFT.

In order to study the effect of thickness on structure and properties of Cr-CrN-Cr-CrAlN coatings, multilayer coatings with different thicknesses were prepared on TC4 titanium alloy by vacuum cathodic arc ion plating. Scanning electron microscope(SEM), X-ray diffraction(XRD), microhardness tester, scratch tester, stress tester, sand erosion tester and tensile tester were used to analyze and detect the surface and cross-section morphology, structure, thickness, hardness, adhesion, residual stress, sand erosion resistance and tensile property of the multilayers. The results show that with the increase of multilayer thickness, particles on the surface of the film increase,the surface quality of the coatings decreases slightly and the coating growth orientation changes from (200) to (111) crystal plane. With the increase of multilayer thickness, the internal stress of the coatings increases, and the hardness, adhesion strength, crack propagation resistance increase first and then decrease. When the thickness is 10.58μm, the optimal mechanical properties with hardness of 3404HV, binding force of 58.6N, crack growth resistance of 758.49 are obtained, and the erosion resistance increases by more than 3 times. After TC4 titanium alloy surface is coated with multilayer film,the yield strength and tensile strength of TC4 are slightly increased, while the elongation after fracture is decreased. In particular, when the thickness of the coating reaches 14.50μm, the elongation after fracture is reduced by 30% compared with that of the substrate. Increasing the coating thickness in a certain range is beneficial to improving the mechanical properties. However, it needs to be controlled to reduce the negative impact on the mechanical properties of titanium alloy substrate.

Microwave vacuum electron devices are used in a wide variety of areas, such as radar, space technology and electron accelerators. The thermal cathode is one of the cores of the vacuum electron devices, its performances directly determine the reliability and lifetime of the electron devices. Therefore, a higher demand is put for thermal cathode. It is important to determine the temperature of the hot cathode accurately. The thermal electron emission performance of different cathodes is summarized and compared, including the comparison of the uniformity of hot electron emission between nano-particulated thin film cathode and traditional coated cathode, and the variation of ion current of evaporates from S-type cathode and M-type cathode (coated with iridium) and N-type cathode (coated with iridium nano-particulated thin films) with temperature and time. The temperature of the cathode surface and the cathode side (molybdenum tube) are tested by the infrared thermometer, optical pyrometer, and thermocouple thermometer (platinum and rhodium-platinum).

As an excellent vacuum smelting technology, the structural design of the water-cooled crucible, the core component of electron beam melting, is particularly important. The crucible cooling performance directly affects the performance and safety of electron beam melting. The influences of crucible water channel structure and melt pool morphology on the cooling capacity of crucibles were investigated through theoretical analysis, numerical simulation, and an experimental assessment. The crucible structure was determined through crucible material selection, melt pool utilization rate analysis, energy loss analysis and cooling calculation. A numerical simulation model was established and used to compare the cooling performance of two types of molten pool crucibles under different loading conditions, and experimental assessment was conducted on crucible with excellent performance. The results show that under different ingot thicknesses, the cooling water temperature and surface temperature of crucible B are lower than those of crucible A in numerical simulation, indicating that the shape of the molten pool and the structure of the water channel in crucible B are more reasonable and have better heat dissipation effects. The experimental assessment shows that the state of crucible B is stable and meets the design requirements.

Vacuum micropumps are of great importance for the vacuum packaging of micro-electro-mechanical systems(MEMS)and vacuum microelectronics devices. Based on the operating principle and process realization, the microminiaturization feasibility of common traditional vacuum pumps is analyzed. The developments of vacuum micropumps including membrane pump, Knudsen pump, vapor-jet/diffusion pump and ion sorption pump are introduced, and the technical difficulties are summarized. The results show that although the vacuum micropumps have obvious decrease in exhausting performances and reliabilities compared with their macro predecessors, they are still necessary for the portable and high-vacuum required microsystems with the merits of low-power consumption and ease of integration.

Cool-down time, base pressure, pumping speed and gas capacity are key parameters of cryopump. In this paper systematic measurements and analysis of 200mm diameter ICP200N cryopump with the designed comprehensive performance test platform were carried out. The results show that the cool-down time of ICP200N cryopump is less than 90 minutes. The base pressure can reach the level of 10^-7Pa without baking, and the main residual gas ingredients are water and hydrogen. The testing method of 30s recovery capacity was given, which is very important in the realistic PVD applications. The corresponding capacity for argon and nitrogen is 820L and 590L, respectively. A simple flow calibration device to improve the pumping speed measurement accuracy was also designed, and the test results show that the nitrogen and argon pumping speed of ICP200N cryopump is comparable with that of international mainstream competitor. So far the ICP200N cryopump has been widely used in the PVD equipment of domestic semiconductor production line.

Vacuum coating is a green manufacturing technology which can prepare high performance coating material and high quality surface under vacuum environment. At present, the hard coating series products which is majorly prepared by physical vapor deposition technology can help the manufacturing industry to achieve low-carbon manufacturing and sustainable development. In the process of vacuum coating application, tribology and surface interface are important scientific issues, while key technical problems need to be solved for advanced vacuum coating equipment, such as high-end core parts, coating process and control system, in particular to the initiative into the fourth tide of the industrial revolution as well as exploring the road of the digital revolution. This paper introduces the specific path of vacuum coating to help low-carbon manufacturing and sustainable development. In addition to mature markets such as tool industry and automobile industry, vacuum coating can also provide important support for the innovation and development of medical industry, aerospace and semiconductor industry.

The NiCrAlYSi (HY3) metal-bonded layer was prepared on the DZ125 alloy substrate by vacuum arc plating (ARC), and then the yttrium oxide stabilized zirconia(6-8YSZ) ceramic coatings were deposited by electron beam physical vapor deposition(EB-PVD) at five incidence angles of 0°, 20°, 40°, 60°, and 80°, respectively. The effect of incident angle on the morphology and properties of the coating was studied. The results show that the thermal barrier coatings with five incidence angles can form columnar crystal structure, and the porosity and columnar crystal tilt angle gradually increase with increasing incidence angles, while the coating thickness gradually decreases. The bonding strength of the coated specimens was tested, and the bonding strength is above 55MPa at the incidence angles of 0° to 40°, and decreases to 15.7MPa when the incidence angle increasing to 80°. Under the thermal shock conditions, TGO is formed between the ceramic surface layer and the substrate.The porosity of the coating is different at different incidence angles, and the growth rate of TGO is inconsistent, resulting in significant differences in the thermal shock life. The thermal shock life of the coating at the incidence angles of 0° to 40° exceeds 4000 times, while that of the coating at the incidence angle of 60° is 3371 times and the shortest one at the incidence angle of 80° is only 1836 times.

The multistage gas distribution system of large-sized square carrier metal-organic chemical vapor deposition (MOCVD) for the preparation of gallium arsenide (GaAs) thin film in the photovoltaic industry is introduced. The core parameters in the design process of the reactor structure, such as the size of the showerhead hole and the spacing between the showerhead and carrier (chamber spacing) are discussed. Based on a self-developed MOCVD reactor model with a carrier of 36×4 inches wafers, the computational fluid dynamics (CFD) method and the gas reaction and surface reaction during GaAs film deposition were used to simulate the gas distribution and chemical vapor deposition (CVD) process with different parameters and chamber spacing. The relationship between cross-orifice pressure difference and gas flow distribution uniformity, and the effect of chamber spacing on gas flow and GaAs film deposition were investigated. The results show that after the primary "spider" plate divides the main gas inlet into 64 sub-gas intakes, the gas distribution uniformity is better, and the fluctuation amplitude of mass flow rate value is only 0.22%. Increasing the hole depth of the showerhead increases the hole pressure difference slowly and linearly, while reducing the hole diameter increases the pressure difference very quickly. Increasing the hole pressure difference of the showerhead can improve the uniformity of secondary gas separation, but the lifting effect is slow. The deposition rate is low and the uniformity is poor at large chamber spacing. With the decreasing of the spacing and the increasing of deposition rate, the deposition uniformity becomes better at first, and then becomes worse gradually due to the turbulence of gas flow.

Mass spectrometer is an important instrument for gas monitoring analysis in many fields. It has the advantages of wide detection range, high sensitivity and faster response speed compared to the traditional gas sensor. A miniaturized process mass spectrometer is developed with a dual filament electron bombardment ionization source and a quadrupole as mass analyzer. The detector works in dual mode of Faraday cup and electron multiplier. The electronic control unit core is combined with a high frequency FPGA system, high current filament power supply, wide mass range RF power supply and high gain composite transconductance amplifier. The test results show that the miniaturized process mass spectrometer has superior properties which has reached the level of mainstream mass spectrometer in the market, and can be widely used in various gas detection occasions.

Mechanical vacuum pump system has gradually replaced the steam vacuum pump system in the field of steel refining, and a reasonable and efficient dust removal system is a necessary measure to ensure the normal operation of the mechanical vacuum pump system. This paper introduces the design and working principle of mechanical vacuum pump dust removal system, and analyzes the common problems and causes of dust removal system. Combined with the relevant engineering practical experience, the dust removal system is optimized and improved, including two-stage gas cooling system, automatic pulse purge system, automatic dust transferring system, and waste gas monitoring and alarm system. The optimized and improved dust removal system has been continuously operated in the RH vacuum refining furnace project of a new electric furnace steel-making plant for more than one year, effectively protecting the operation of mechanical vacuum pump and meeting the production process requirements for RH vacuum refining furnace.

As a core component of Roots vacuum pump, the rotor has an important influence on the performance, and the design of rotor profile is critical to design rotor. In this study, the rotor profile is designed with the waist as the elliptical line, and its profile inside the pitch circle is composed of elliptical lines, while the profile outside the pitch circle is composed of the conjugate curves of elliptical lines. Firstly, the elliptical line located at the waist and its meshing angle are determined. Then, based on the meshing relationship between the two rotors, the conjugate curve of the profile line located outside the pitch circle is solved to obtain total rotor profile. Finally, the rotor of the Roots vacuum pump with a pumping speed of 70 L/s is designed, and the relationship of rotor volume utilization with independent variable parameters is analyzed. This profile has a significant advantage in the volume utilization rate that can be greater than 50%, compared to the rotor profile with the elliptical line at the top.

With the rapid evolution of the MEMS and VLSI technologies, small nano-satellite, being low cost and competent in complicated tasks, has become a crucial orientation of the commercial aerospace in the world. The on-orbit maneuverability ability of the small nano-satellite promotes the serial micro-electric propulsion system′s development and on-orbit verification. In this paper, the demands of the electric propulsion system for the small nano-satellite are firstly demonstrated. Then the characteristics of the micro-electric propulsion system are introduced, including the product engineering and on-orbit verification of the micro-electric propulsion system at domestic and overseas. Finally, the development and on-orbit application of the micro-electric propulsion in China are prospected.

This article briefly introduces the basic principles of relativity and quantum mechanics, which cites the recent scientific news to discuss the application and usage of vacuum science and technology in these fields. As we know(everyone knows, including the content that does not appear in the books), as the mother of the universe, vacuum is bigger and older than the universe. Moreover,vacuum is the physical environment of relativity and quantum mechanics. Vacuum science and technology is an essential theory for the study of relativity and quantum mechanics. The modern physics is on the eve of a great revolution. The research problems of black holes, dark matter, dark energy, gravitational waves and the origin of particles have put forward serious challenges to physics. Perhaps physics can gain ground from studying scientific problems or resolving the contradictions between relativity and quantum mechanics. This article is divided into three parts: (1) The recent progress of relativity and vacuum technology; (2) Previous ideology frames were sorted out; (3) The relevant knowledge of quantum mechanics and zero point energy.

Using electron beam evaporation equipment to deposit high-quality aluminum film is a big challenge in the film process. Therefore, a method was proposed to deposit aluminum film by using a modified Al₂O₃ crucible as the lining pot, and adding materials and pre-melting them three times. The effects of different evaporation rates on the electrical resistivity, grain morphology and composition of aluminum films were studied. The results show that the convex molten aluminum liquid surface can increase the contact angle with the crucible wall, basically eliminate the aluminum oxide impurities in the aluminum film. With the increase of evaporation rate, the grain size of aluminum film increases and the average resistivity decreases. The aluminum film with purity of 99.9% and the lowest resistivity of 3.4×10^-6 Ω·cm can be prepared by adding materials for pre-melting three times.

For the requirement of tritium gas transportation, a set of bellow pump is developed, which includes a boosting pump and a rocking pump. Swashplate-rod with piston structure is developed for the boosting pump, in which three reciprocating plunger pistons are adopted to get high compression ratio to deal with the low vacuum and booster. Rocking piston is adopted in rocking pump to increase the gas flow and decrease the vacuum pressure, which ensure the inlet pressure is 50Pa and outlet pressure is 0.4MPa. Double bellows are used to separate the tritium from the shaft system, which can prevent the transporting gas from any pollution. Helicoflex sealing is used to separate the tritium from the environment, and leaking ratio of 1.0×10^-7Pa·m³/s is achieved. The self developed circulating and boosting pump can meet the request of tritium boosting transportation.

The interface reaction between a Zr containing superalloy and different crucible refractory materials was investigated by dross test, scanning electron microscope(SEM) and energy dispersive spectroscopy(EDS). The results show that the ZrO₂ produced by the reaction between Zr in superalloy and oxide ceramic crucible is the main source of dross in alloy ingot. The thermodynamic stability of MgO crucible is lower than that of Al₂O₃ crucible, and its reaction with Zr is more intense, resulting in more ZrO₂ dross. The microstructure of crucible also has an important influence on the interfacial reaction. When the density of the crucible is high and the surface is smooth, the generated ZrO₂ is attached to the crucible surface to form a dense ZrO₂ layer, which prevents the further reaction between Zr and Al₂O₃ crucible. When the surface of the crucible is rough, it is difficult to form a dense ZrO₂ layer, and the generated ZrO₂ enters the alloy melt to form dross. Therefore, the use of Al₂O₃ crucible with high density, fine structure and good surface quality is conducive to reduce the reaction between superalloy and crucible refractory, and reduce the pollution of alloy ingot.

In this paper, the analytical expressions of three widely used quantitative depth profiling models, atomic mixing-roughness-information depth(MRI) model, up-and-down slope(UDS) model and roughness-cascade mixing-recoil implantation(RMR)model are systematically discussed. Firstly, the profile characteristics of the three models are analyzed according to definition, formula derivation and simulation analysis. Then, these models are compared in details with the partial depth resolution functions, the depth resolution function, the analytical expressions of analyzed thick film layer and the fitting of experimental data. Finally, the shortcomings of the UDS model are explained, and the incorrect description of the RMR model are corrected. The reliability and superiority of the MRI model are verified by the dynamic characteristics of measured/simulated depth profile.

The smelting and purification methods of active metals,the basic forms of plasma beam melting furnace and the current situation at home and abroad are summarized. The composite melting technology of ion beam cooling bed and induction cold crucible and induction cold crucible continuous casting technology are introduced. A magnetic stirring cooling bed technology is proposed. The application of plasma technology in metal smelting reduction and purification is introduced, and the application direction of plasma technology is prospected.

Graphene, a new two-dimensional material with excellent performance, has great potential for applications in the fields of aerospace, electronic devices, and bio-medical. Plasma enhanced chemical vapor deposition (PECVD) was used to prepare grapheneon copper foil using a mixture of hydrogen and methane gas. The mechanism of H₂ on the nucleation and growth of graphenein growth and cooling stage of PECVD was studied. The results show that in the PECVD process, the pre-etching of copper substrate by H₂ plasma before graphene growth would increase the roughness of the substrate, which is not conducive to the growth of low-density and large-size graphene grains. During the growth process, H₂ could etch multiple layers of graphene, and a single layer of graphene could be formed at higher H₂ flow rate. After the end of growth, holdingthe graphene in H₂ for a certain period of time, it would be etched into ribbons, and the etching would be intensified with the extension of holding time.

High-precision transmission control of electron beams is important to ensure reliable applications of electron guns in metal melting, evaporation coating, and electron beam welding. The transmission control technology of electron beams in the evaporation environment of metal materials was studied, and a 30 kV electron beam deflection model was established based on CST particle simulation analysis software. The influence of the structure and position parameters of the deflection device on the distribution of electron beam was analyzed, and the control parameters and structure of the electron beam deflection that meet the requirements were obtained through simulation design optimization. The test results show that the electron beam transmission trajectory under the optimized structure is controllable, and the established 30 kV electron beam deflection system meets the requirements.

The drift tube linac(DTL) is the main part of CSNS linac, which is responsible for accelerating the negative hydrogen ion beam with a pulse current of 15mA from 3MeV to 80MeV, and then injecting it into the fast cycle synchrotron(RCS) for further acceleration. In order to avoid energy loss, ion beam acceleration must be completed in a high vacuum environment.This paper first introduces the composition of the DTL tank vacuum system, and then analyzes the current vacuum leakage, describes in detail the vacuum leakage solutions in different situations such as pickup leakage, drift tube leakage(including water leakage, air leakage, internal leakage), and reduces the leak detection area by simulation calculation by Monte Carlo method. Due to the high leakage frequency of drift tubes, this paper gives a standardized operating procedure for drift tube leakage to improve leak detection efficiency.

The formation mechanism of air hole defects on the surface of superalloy ingots produced by vacuum induction melting process was studied through microstructure observation of the superalloy ingots and thermogravimetric analysis of the attachments in the ingot mold. The results show that during pouring, a small amount of rust(Fe₂O₃) attached to the inner wall of the ingot mold decomposes into Fe₃O₄ under the action of high temperature, during which gas outgassing occurs. The expansion of the generated gas at high temperature is the main reason for the formation of holes on surface of alloy ingot.

The computational fluid dynamics (CFD) method was used to simulate the screw dry vacuum pump by numerical simulation and calculation, and the analysis method for the flow field of screw dry vacuum pump was established. The flow area in the pump chamber was modeled in 3D, and the rotating and fixed domains were meshed separately with SCORG and ANSYS-ICEM softwares. The transient simulation method was used to obtain the distribution of pressure field, speed field and temperature field in the pump, and the parameters such as pumping rate were calculated. Perform mesh agnostic analysis was carried out, and the comparison between analysis results and the theoretical data shows that the numerical simulation results are reliable and in line with expectations.

The screw dry vacuum pump realizes multi-stage compression in one pump chamber and does not use liquid sealing, it is an excellent equipment for gas transportation under the "dual carbon" target. The article analyzes the design principles of screw dry vacuum pumps. The characteristics and requirements of screw vacuum pump in use scenarios are studied, and the particularity of vacuum system in chemical engineering is pointed out. The scene based module system integration, screw pump sealing structure, internal cooling structure and intelligent control are proposed. The database establishment and control mode optimization measures that need to be addressed in the intelligent process are discussed. It is recommended to use scenario requirements as the design principle based on theoretical design to achieve safe and efficient engineering application.

The basic principles, particle trajectories and structures of the compact emission guns for electrons and argon ions are introduced respectively. The typical electron guns are used for charge neutralization, pulse emission and high energy electron diffraction. The types of argon ion gun are usually classified to cold cathode, hot cathode and plasma sources. The compact emission guns are playing important roles in the development and application of scientific research, semiconductor industry, life sciences, defense and aerospace.

A new type of continuous strip steel coating equipment is introduced, and the technological process, structure and function of each part of the equipment are designed and analyzed in detail. This equipment fabricates a metal film on the strip steel surface through vacuum evaporation coating process, which can significantly improve the corrosion resistance of the strip steel. The experimental verification shows that this equipment can form a Zn-Mg-Zn composite film with excellent protective properties on the surface of the steel strip.

In low temperature storage and transportation, due to the outgassing of materials in the vacuum interlayer, the vacuum degree of the interlayer will decrease, the heat will be introduced from the outside to increase the evaporation rate of the low temperature container and the loss of low temperature liquid, and the vacuum life will be shortened. Therefore, it is very important to study the outgassing properties of materials in vacuum interlayer. In this paper, the outgassing rate of multilayer insulation material and FRP in vacuum for low temperature storage tank is tested and studied. The outgassing rate per unit area of multilayer insulation material and D3848 FRP is 4.93×10^-8Pa·m³/(s·m²) and 1.13×10^-7Pa·m³/(s·m²). The results can provide a reliable basis for the design of adsorption dose of vacuum interlayer.

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 chip-level ion source structure with a triode-type field emitter is designed for the micro mass spectrometer of spacecraft, which consists of a gas ionization by electron impact and an ion extraction section. The structure of the ion source is composed of five layers of electrodes. A chip-level ion source prototype was prepared using MEMS technology, and the electron flow, ion flow and stability were tested. The results show that the chip-level ion source can generate an electron current of over 0.357 mA, and the received ion current can reach 527 pA, meeting the functional requirements of the ion source for micro mass spectrometers in space exploration missions.