The ultra high vapor and oxygen barrier film, which can protect the organic electronic device from water vapor erosion and prolong lifetime, is widely used in flexible electronics, such as organic thin film solar cells, OLED displays, quantum dot displays and other electronic packaging. According to the research status of the preparation technology of high barrier film, in order to improve the performance and meet the demand of rapid development of flexible electronic packaging, the effect of substrate material is analyzed, the multilayer preparation technology is summarized. Finally, the future development trend of barrier film technology is prospected.

The ITO films were deposited at room temperature by DC magnetron sputtering of a lab-made ITO target on organic glass substrates. The photoelectric property of the ITO film was evaluated by changing the process parameters of sputtering power, sputtering pressure, target distance and oxygen-argon flow ratio. The ITO films were characterized with ultraviolet visible near infrared spectroscopy. The results show that the transmittance of ITO films decreases with the increase of sputtering power and target-substrate distance. When the sputtering power is 110W and the target-substrate distance is 70mm, the transmittance and conductivity of ITO films are better. In the near-ultraviolet light band and the near infrared light band, the transmittance of the ITO film decreases as the sputtering pressure increases. When the oxygen-argon flow ratio is 4:30, the ITO film shows the best transmittance and comprehensive performance in the visible light range from 500nm to 600nm.

When using tungsten crucible and electron beam evaporation equipment to evaporate silver thin film, silver is infiltrated with tungsten crucible in the molten state,and the liquid level of molten metal in the crucible is concave. Such concave evaporation sources often lead to poor uniformity of the as-deposited films. According to the principle that the microstructure of the object surface will change the contact angle between liquid and solid, a groove array is fabricated on the smooth inner wall of tungsten crucible by chemical corrosion. By changing the contact angle between the molten metal material and the inner wall of the tungsten crucible, the wettability of liquid silver and the wall of tungsten crucible can be adjusted. The results show that when the groove width is about 1mm,the depth is about 0.5mm and the period is about 2mm, the inner wall of the molten silver and tungsten crucible becomes no longer infiltrated. 100nm-thick silver film is evaporated with unmodified and modified tungsten crucible, respectively, and it is found that the uniformity of the evaporated film can be improved effectively by using the modified tungsten crucible.

The porous metal materials are a new type of metal materials with excellent properties. This review briefly describes the preparation methods and applicability of several commonly used porous metal materials.Then the application of porous tungsten materials in the fields of microwave vacuum devices and space electric propulsion technology is introduced, and the existing problems in the preparation of porous tungsten materials are pointed out. In response to these problems, the preparation process of porous tungsten materials and parts is studied in depth. The tungsten powder is classified by the classification technology. The results of the laser particle size tester show that the size of classified tungsten powder particles is more concentrated. The gas purification and detection system can remove residual oxygen and water in the hydrogen gas, and reduce the dew point of hydrogen from -50℃ to below -90℃, which provides a good sintering atmosphere for preparing the non-oxidized tungsten sponge matrix. Porous tungsten materials are prepared by cold isostatic pressing technology and high temperature sintering, and the porosity of porous tungsten materials is studied by mercury porosimeter. The pore size distribution becomes narrower and the pore size becomes more uniform. The porous tungsten-copper alloy materials are prepared by vacuum impregnation. The impregnation rate is much higher than that of copper impregnation under the hydrogen condition, and the impregnation rate is increased by more than 4%. The tungsten copper alloy substrate is heated by a high frequency heating coil crucible localized firing. The results show that this technology has the advantages of no residual on substrate surface, short time, no pollution to furnaces and environmental. The porous tungsten have been successfully used in the microwave vacuum electron devices.

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.

This paper introduces a set of virtual instrument experiment system for school teaching and enterprise training based on the unity3D platform. With various virtual instruments, the system provides high reality experimental environment with intelligible human-computer interaction and can well simulate the manipulation of the experiment. The as-developed system has two forms, in which one is the realization of VR scenes and the other one is the client APP form. It is suitable for different cenes and meets different teaching and training needs. This paper also provides a reference for the development of such VR platforms.

As the main equipment for the industrial production of metal powder, vacuum atomization milling equipment is widely used in key areas including additive manufacturing, powder metallurgy, aerospace and medical treatment. This paper focuses on the most common vacuum atomization milling technology, and their characteristics and development directions are deeply studied and discussed. Firstly, the technical background of atomized milling and the common classification of current milling methods are briefly introduced, and then combined with the core performance indicators of the technology and equipment used by the major atomization milling equipment manufacturers and metal powder suppliers, the vacuum atomization milling methods including VIGA(vacuum induction-melting gas atomization), EIGA(electrode induction-melting inert gas atomization), VIGA-CC(water-cooled copper crucible vacuum induction-melting gas atomizing) and PREP (plasma rotating electrode-comminuting process)are described in detail. The future development direction of atomization milling technology and equipment is also prospected.

Study of the rotor profile of Roots pump is a core part of Roots pump design, and the circular arc rotor profile is one of the widely used for Roots pump. In the design of circular rotor profile, the theoretical rotor profile is designed based on conjugate properties firstly. Then the actual profile and casting blank profile of the rotor are obtained based on the theoretical profile. In this paper, the actual profile and casting blank profile design method based on the rotor circular arc line is proposed on conjugate properties to greatly simplify the analysis and design process. Finally, the circular arc rotor profile and its rough machining and finishing methods are designed for a 70L/s Roots pump.

Low-carbon development of metallurgical industry with high energy consumption and high carbon emission has become the consensus of the international community and industry under the background of carbon emission peak and carbon neutrality. As one of metallurgical industries with the largest carbon emission per unit product, carbon emission reduction of magnesium production is imperative. Developing new low-carbon magnesium production technology is the way forward. This paper analyzes the shortcomings of the Pidgeon process and introduces the principle and advantages of the new aluminothermic reduction methods of magnesium production. The results show that the Pidgeon process has the disadvantages of large raw material consumption, high energy consumption and large carbon emission. Limited by the reduction principle of magnesium production, it is difficult to further reduce the energy consumption and carbon emission. Compared with the Pidgeon process, the aluminothermic reduction process has the advantages of less raw material consumption, high production efficiency, low energy consumption and zero discharge of waste residue, and the carbon emission of which can be reduced by 30%-50%. The aluminothermic reduction process with a lowcarbon emission and pollution-free green magnesium production process has a good application prospect under the background of carbon emission peak and carbon neutrality.

This paper discusses the common structure and future development direction of vacuum induction furnaces.First of all, the characteristics of different structural furnace types are introduced. Then the overview of various furnaces in the current mainstream market environment is analyzed. Finally, the future development direction of vacuum induction furnaces is predicted through the comparison and analysis of technology and market conditions.

The cross-sectional profile of the existing screw rotor has sharp points and the contact line is discontinuous. To solve this problem and simplify the composition of the section profile, this paper uses a sinusoidal helix to smoothly connect the tooth tip arc and the tooth root arc, and then proposes a new type of fully meshed sinusoidal helical screw rotor. The meshing model of the sinusoidal helix and its conjugate curve are proposed, and the equation of the section profile is deduced. The influence of the radius ratios and helical central angle of the new section profile on the performance of the twin-screw vacuum pump is analyzed, and their reasonable value range is given. The results show that the section profile of the as-proposed new full meshing screw rotor is completely smooth, and the spatial contact line is continuous, which is beneficial to improve the performance of the twin-screw vacuum pump.

The transition flow is solved by the joint calculation of NS and DSMC methods. The NS/DSMC coupling method has the advantages of the computational efficiency of NS method and the computational accuracy of DSMC method.In this paper, the principle of key technologies in the development of coupling method is introduced in detail, the application progress of coupling method in spatial plume research is discussed, and the shortcomings of computational domain partition method are explained. Then the application of coupling technology in the flow around neighbor spacecraft is analyzed. It is proposed that the error between the coupling calculation and the experimental results may be caused by DSMC statistical scattering, which can be eliminated by cumulative statistics. In addition, the application of NS/DSMC coupling method using two-phase flow model in MEMS field is also discussed. Finally, the application of coupling method in vacuum field and the research direction of coupling algorithm in the future are prospected.

As a flexible material with similar structure to biological tissue, hydrogel has been widely used in flexible sensors and other fields. However, the mechanical properties of hydrogel are poor because of its high water content, and the hydrogel is easy to freeze and fail under low temperature environment. This paper reviews recent studies of hydrogel from the aspects of toughening mechanism, antifreeze method, and fatigue characteristics. Firstly, the mechanical properties and internal structures between different toughening hydrogels are compared. Secondly, the antifreeze method of hydrogel under low temperature is discussed. Finally, the fatigue damage characteristics of hydrogel in long-term static or cycle mechanical loading are summarized. In the future, it should be committed to increase the water-freeze resistance of hydrogel, and further study the hydrogel fatigue failure mechanism, which may provide theoretical basis for the application of low temperature and fatigue resistant hydrogel sensors.

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.

Nowadays, more and more vacuum test need to detect pressure inside the test specimens. Although direct installation of sensors is the most effective and accurate way to measure the pressure of the test specimens. However sometimes sensors cannot be installed in the test specimens, which makes direct measurement difficult to be realized. In this paper, internal pressure of test specimens under molecular flow was simulated by the method of Monte Carlo. Geometric model of test specimens were established. Material degassing quantity was considered. The variation of vacuum degree with time was calculated under molecule flow. This paper provides a theoretical basis for the pressure prediction of specific location during vacuum test.

This paper introduces an ion beam assisted deposition surface modification technology combined with ion implantation and vapor deposition film based on general vacuum winding aluminum plating machine. By adding a set of auxiliary bombarding ion source on ordinary winding plating equipment to establish an ion assisted deposition system, transparent alumina membrane plating can be realized. The equipment structure, characteristics and working principle of this coating method are described, the application prospect of this coating method is presented. Aluminized film plating can also be realized on the equipment, breaking through the single response of ordinary aluminum-based coating types. This technique responds to the national call for the realization of the localization of aluminum oxide evaporation coating equipment.

In order to study the effect of matrix surface microstructure on the adhesion between coating and matrix, the adhesion between coating and matrix was tested. The hardness of the coating was measured. The interfacial microstructure between coating and matrix,and the matrix surface microstructure were observed. The relationship between adhesion and surface morphology was analyzed. The results show that after water blasting and dry blasting, V-grooves are formed on the matrix surface, which are expressed as type θ₁ and type θ₂ respectively（θ₁<θ₂, θ is the ratio of groove opening width to groove depth）. The matrix surface microstructure can significantly affect the adhesion between coating and matrix. But the phase, density and residual stress of coating are not influenced. According to the nucleation mechanism, the atoms will nucleate and grow at the upper edge of θ₁ “V” groove. A large number of atoms are blocked, resulting in hollow bottom of “V” groove. In θ₂ “V” groove, a large number of atoms enter the groove. With the diffusion of atoms, the almost completely filled“V” groove is formed. As a result,the bonding area of coating and matrix increases, and the adhesion of coating and matrix improves.

Time of flight second ion mass spectrometry(TOF-SIMS) and pulsed radio frequency glow discharge optical emission spectrometry(Pulsed-RF-GDOES) are two important depth profiling techniques, the former one is widely used in the fields of semiconductor industry and material science, while the latter one is usually applied to the analysis of industrial coating and surface oxynitride. Mo/Si nano-multilayers have been widely used in nanolithography, soft X-ray/EUV microscopy, solar astronomy and other fields because of their excellent reflection characteristics. In this paper, Pulsed-RF-GDOES and TOF-SIMS depth profiling data of Mo(3.5nm)/Si(3.5nm) nano-multilayer are evaluated quantitatively by the convolution and deconvolution methods with the resolution function of the atomic mixing-roughness-information depth(MRI). The layer structure, interface roughness and depth resolution upon depth profiling are obtained. The results show that GDOES depth profiling yields larger sputtering induced roughness, and the depth resolution of SIMS is better than that of GDOES.

The working principle and development status of vacuum arc remelting furnace and vacuum arc skull casting furnace are described. This paper introduces the development of vacuum arc remelting(VAR) technology control technology, and points out the important significance of arc detection and regulation for the safe operation of large vacuum arc skull furnace. Although the melt rate control realizes the stability of the profile of the melt pool mushy. However, the arc motion changes the heat distribution of the pool. The optimization of arc distribution state based on melt rate control is the development direction of high quality ingots and process equipment. According to the arc motion characteristics, the arc distribution model is divided into four categories: concentrated, diffusive, eccentric and rotating. The distribution model of diffusive arc plays an obvious role in improving the profile of melt pool and the quality of ingots. VAR control technology is divided into three components: arc distribution, melt pool characteristics and solidification process. Aiming at the electromagnetic characteristics of arc, magnetic field is used to detect and regulate the arc distribution, which will bring new technological innovation to VAR process. The control system with Hall effect magnetic field sensor array and Helmholtz coils has been applied in industrial VAR furnace to verify the effectiveness of the control system in arc detection and regulation.

In recent years, palladium thin films have attracted wide attention due to their excellent properties such as low resistivity and high catalytic activity. Palladium and its alloy thin films have gained more and more interest from researchers in the applications of integrated circuit interconnection, hydrogen sensing, hydrogen storage and catalysis. There are many researches of the preparation of palladium metal film, this article focuses on the research development of preparation of palladium membrane using physical vapor deposition, chemical vapor deposition, atomic layer deposition and plasma auxiliary atomic layer deposition technology, and discusses the pros and cons of various preparation methods, sums up the precursor used to do, and prospects the development trend of preparation technology of palladium film.

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.

The preparation method of protective and passive film for Cu electrode of enhanced power device is introduced. Al₂O₃ films are deposited on copper by thermal ALD and plasma enhanced ALD techniques. The effects of different ALD techniques, oxidant type, deposition temperature and carrier gas on the quality of Al₂O₃ films and the protection performance for Cu oxidization are studied. The results show that oxidants play an important role in Al₂O₃ film quality and the protection performance for copper electrode. When ozone(O₃) is used as oxidant, Al₂O₃ film deposited on copper layer is easy to fall off, and the adhesion to copper surface is very poor. Using oxygen plasma (O-) as oxidant, copper surface is oxidized to form CuO_x layer. With H₂O as oxidant, the Al₂O₃ film obtained at low temperature of 100℃ is dense without obvious defects, and has excellent bonding force with copper layer. When the deposition temperature is higher than 200℃, the defects of Al₂O₃ deposited by ALD increase obviously. In plasma enhanced atomic layer deposition, when the carrier gas is Ar, the thickness of Al₂O₃ film is not uniform, and the copper electrode is strongly oxidized.

To study the application of ITO films in the 1064nm laser window of wide magnetic shielding, ITO thin films were prepared by using dual ion beam sputtering technology under different technological conditions. According to the test results of photoelectric properties of the films,the effects of oxygen flow rate, auxiliary ion source and substrate baking temperature on the transmittance and conductivity of ITO films were analyzed. Using Ti₂O₃ and SiO₂ as high and low refractive index materials and ITO film as electromagnetic shielding film on K9 glass substrate, a 1064nm laser window film with 0°-45° incidence was designed and fabricated for 2-18GHz efficient shielding. The test results show that the thin film prepared under suitable technological conditions has good transmittance and electromagnetic shielding performance, and is suitable as a high-efficient electromagnetic shielding,0°-45° incident of 1064nm laser window film.

As a dry medium and low vacuum pump, screw vacuum pump has many advantages such as wide pumping speed range, low energy consumption, no oil pollution, etc., and is widely used in various fields. In order to serve the national carbon neutral development strategy, this paper applies the accounting and management method of carbon footprint to the design and manufacture of screw vacuum pumps. By tracking, analyzing, accounting and managing the carbon footprint of the entire product life cycle, specific measures to reduce carbon emissions are put forward from the perspective of design, processing and manufacturing, supply chain transportation and institutional levels. The research of this work will help enterprises to formulate relevant carbon neutral goals, complete the accounting of carbon footprint, and achieve the purpose of energy saving and emission reduction.

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.

Compared with the vapor jet vacuum pump system served at present,the high differential pressure Roots pump combination pumping system is being widely used for large vacuum distillation unit because it has the characteristics of quick start and obvious energy saving effect.In this paper,one kind of combination pumping system consisted of high differential pressure roots pump used in a large vacuum distillation deep cut unit is introduced,and the structure,control principle,performance parameters and solutions to some key technical problems of the system are described in detail.

In the China spallation neutron source（CSNS） large scientific platform, 1.6GeV high-energy protons produced by a high-energy proton accelerator are used to bombard a solid tungsten target. The back neutron beam generated in front of the target returns through the proton channel to the neutron experiment area is called the back neutron source（Back-n）. It has the characteristics of wide energy spectrum（0-200MeV）and large neutron yield（2×10¹⁶n/s）, which is suitable for nuclear data measurement and other high-energy physics research. The Back-n vacuum system consists of a 26m ultra-high vacuum system shared with the high-energy proton beam and a 54m high vacuum system dedicated to the passage of the neutron beam. The two vacuum systems adopt different vacuum acquisition schemes and process routes,and are separated by a neutron beam window. An ultra-high vacuum gate valve is installed on the ultra-high vacuum side to prevent the damage of the neutron beam window from affecting the operation of the accelerator. This article introduces the design and operation of the Back-n vacuum system. The establishment of the vacuum system provides high-quality vacuum conditions for the experimental research of the Back-n.

A high vacuum chamber suitable for MEMS ion source testing was designed. According to the current research on the high vacuum chamber used for mass spectrometry test, in view of the high vacuum acquiring ability, maintaining ability and the convenience of frequent use, and considering the structural strength, inner wall exhaust and other factors, the cylinder structure which can meet the requirements of both strength and low exhaust rate was selected. Based on ANSYS software, the structural stability and dangerous point distribution of the chamber under high vacuum were analyzed comprehensively. The optimized selection range of wall thickness was determined. This study can provide a theoretical basis for the design of high vacuum chamber.

To address the problems of low deposition rate and uneven film thickness in the preparation of SiC films by pulsed laser method and sublimation method, this paper adopts the vacuum DC magnetron sputtering technique to deposit SiC films on the surface of flat glass substrate using a SiC target with high carbon content. The effects of different parameters on the deposition rate and film thickness uniformity were investigated by varying the DC power and sputtering pressure. The thickness, cross-sectional morphology and Si, C content of the films were characterized by step meter, scanning electron microscope（SEM）and energy spectrometer（EDS） respectively to obtain the optimal process parameters. The experimental results show that the film deposition rate reached 15.39nm·min^-1 when the sputtering power was 2000W under the same sputtering air pressure condition.The variation coefficient of thickness uniformity of the deposited films was within 3% while the film deposition rate reached 10.67nm·min^-1 when the sputtering air pressure was 0.8Pa under the same DC power condition. In addition, the films prepared by DC magnetron sputtering were dense and porosity-free inside,and the Si, C content was above 99%.

This paper presents a design and calculation method of O-type rubber sealing ring for vacuum. The approximation equation for calculating the elastic deformation pressure of O rubber sealing is derived, combined with the design parameters of O sealing ring that have been successfully used in engineering practice, O rubber seal compression elastic force and atmospheric pressure in vacuum environment are calculated, and the corresponding relationship between them is obtained by polynomial fitting method. The atmospheric pressure of O-type rubber seal ring to be solved is the input condition,and the geometric parameters of O-type rubber seal ring are inversely solved by using the approximate formula of elastic deformation pressure of the seal ring. In order to verify the reliability of the calculation method, Mooeny-Rivlin model was used to simulate the calculation results. The results show that the maximum stress of the flange O-type rubber sealing ring with diameter of 7500mm is about 7.01MPa under atmospheric pressure, and no permanent damage will occur, which proves that the design and calculation method of O-type rubber sealing ring is feasible.

With the wide application of thin film materials in modern industry,arc ion plating technology has become an important method for preparing functional films, such as functional surface modification and surface metallization of composite materials in the field of aerospace. In order to verify the state of cathode spot movement under different magnetic fields, the cathode spot on Ti target was controlled by magnetic field. TiN films were prepared under five magnetic fields, and the surface morphology, microstructure, chemical composition and thickness of TiN film were detected and analyzed through scanning electron microscope, energy disperse spectroscopy, step profiler and X-ray diffractometer. The results show that the film has the least number of large particles, the film is the thickest, and the crystal preferential growth direction is (111) crystal plane, when the cathode spot controlled by the magnetic field is uniformly distributed on the entire Ti target surface and the cathode spot movement speed increased.

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.

The intermediate refractive index material required for preparing gradient refractive index films is obtained by adopting the method of dual-source co-evaporation of MgF₂ and ZnS and controlling the deposition rate ratio of both materials. The G|HL|A double-layer anti-reflection film is graded into 5 layers, and keeping the total optical thickness unchanged, the gradient index anti-reflection film with a gradient of 1.91,1.77, 1.64, 1.48, and 1.38(wavelength of 532nm) along the thickness direction is prepared. All samples are tested for optical and laser damage characteristics. The results show that the refractive index of the composite film obtained by double source co-evaporation of MgF₂ and ZnS and the deposition rate ratio of the two materials satisfy the relationship deduced according to Drude theory. The refractive index of the composite film accords with the normal dispersion. Except for the material with the refractive index of 1.91, of which the absorption is large(extinction coefficient at 532nm is 0.01), the other composites show small absorption(extinction coefficients at 532nm are less than 0.002). When all the monolayer films are irradiated with 100mJ energy laser, the composite film with the refractive index of 1.64 has the lowest laser damage, showing higher resistance to laser damage than single-component ZnS and MgF₂ films. When the double-layer anti-reflection film is equivalent to five layers with graded refractive index, the passband range is extended from 205nm to 380nm, and the laser damage threshold is increased from 2.0J/cm² to 3.7J/cm², which is increased by 85%. It can be seen that it is feasible to prepare thin films with graded refractive index by adjusting the evaporation rate ratio of the two materials. As long as the ratio of the two materials is appropriate, using co-evaporation technology can obtain a composite film that has higher resistance to laser damage than a single-component film. The graded index anti-reflection film has better optical properties and higher laser damage threshold than double-layer anti-reflection film.

In order to predict the time of gas pressure drop in the rapid decompression environment simulation system, an approximate theoretical calculation model for rapid decompression was established based on the orifice outflow principle of hydrodynamics, and the numerical iterative calculation method was given. At the same time, the finite element simulation method was used to analyze the pressure balance process, and a set of test system was built. By comparing the results of the two methods with the experimental data, the correctness and feasibility of the calculation method are verified.

In order to improve the service performance of titanium alloy, multilayer films with different R_Cr-CrN:R_Cr-CrAlN modulation ratio 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 and sand erosion tester were used to detect and analyze the cross-section morphology, structure, thickness, hardness, adhesion, residual stress and sand erosion resistance of the multilayer films. The results show that the thickness of multilayer films is 7-8μm, the transition layer is about 1.5 μm, and the thickness of single cycle is 150-200nm. All the multilayer films exhibit (200) preferred growth face centered cubic structure. With the increase of the proportion of Cr-CrAlN layer, the hardness, residual stress and adhesion of the film increase accordingly. The sand erosion resistance of multilayer films with different modulation ratios at 90° angle of attack is more than 3 times that of TC4 substrate before they are completely damaged, and at 30° angle of attack, the sand erosion resistance of multilayer films is about 8 times that of TC4 substrate. When the modulation ratio of R_Cr-CrN:R_Cr-CrAlN is 1∶2, the multilayer films have the best comprehensive properties.

The performance of agricultural machinery farming parts is seriously affected due to wear failure, and the development of agricultural mechanization is restricted. Surface modification technology has become an important technical means to improve the wear resistance of farming machine parts owing to its advantages of flexible technology, strong applicability, convenient operation and low cost. The surface modification technology has been widely used in agricultural machinery,such as thermal spraying, spray welding, surfacing welding, cladding and biomimetic technology. The advantages and disadvantages of different technologies and their applicable conditions are different. This paper introduces the research situation of surface modification technology in improving the wear resistance and surface performance of farming machine parts, and puts forward its application prospect and development trend.

The cylindrical specimens of a single crystal superalloy with diameter of 15mm and 30mm were prepared using the same melting process and directional solidification process. The stress rupture properties at 980℃/250MPa and high cycle fatigue properties at 800℃ of the alloy with two casting dimensions were tested. Dendrite microstructure, the as-cast γ′ phase, heat treated γ′ phase, micropore, stress rupture and high cycle fatigue fractograph and fracture microstructure of the alloy with different casting dimension were examined by OM, SEM and TEM. The results show that with the increase of casting dimension, the primary dendrite arm spacing, the size of as-cast and heat treated γ′ phase, and the size and volume fraction of micropore increase. The stress rupture properties of the alloy decrease, the fracture mechanism has no obvious change and is dimple model with casting dimension increasing. The quantity and size of micro-crack and the γ′ raft thickness on the stress fracture microstructure increase with the casting dimension increasing, while high cycle fatigue properties of the alloy decrease. At last, the relationship between the property and microstructure of the alloy is discussed.

The beam power of the CSNS II accelerator will be upgraded from 100kW to 500kW, which requires the average beam power of the linear accelerator to be increased from the current 5kW to 25kW, and the pulse beam intensity to be increased from 12.5mA to more than 40mA. For this reason, the Penning type surface negative hydrogen ion source currently in use will be replaced by a radio frequency（RF） negative hydrogen ion source. Considering that the beam cutting ratio of the beam chopper ranges from 35% to 50%, and the LEBT transmission rate can reach 75% to 95%, the RF negative hydrogen ion source needs to produce a negative hydrogen ion beam of at least 50mA. Therefore, the hydrogen gas consumption of the ion source needs to be increased from the current 10sccm to more than 20sccm,and the pressure of LEBT second chamber is required to be ≤5.0×10^-3Pa. Based on this, the ion source and the LEBT vacuum system are modified in this paper,and the beam transmission rate of LEBT is improved. In addition, the pumping speed of hydrogen with two domestic and imported magnetic levitation molecular pumps is compared,which provides a certain reference for the selection of molecular pumps and localized substitution.

The insulation of medium frequency magnetron sputtered silicon oxide films were surveyed by resistance measurement with megohm meter. The films were characterized by XRD and FTIR. The results show that the film is amorphous SiO_x. Instantaneous resistance(R_i) when the probe on the megohm meter attaches the SiO_x film is related to the absorbing peaks near wavenumber 900cm^-1(peak a) and 760cm^-1(peak b) on FTIR spectrum. As R_i rises, peak b shows red shift and the peak height ratio of peaks a and b rises. It can be concluded that R_i rises with content of oxygen in SiO_x film. The abnormal products with lower R_i can be recovered to normal range by 250℃ heating treatment. The insulation decrease of SiO_x films in production process may be caused by abnormal change of oxygen concentration in the chamber.

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.

Manned spacecraft hatch is the aisle for astronauts and cargo to enter and leave the sealed capsule of spacecraft. Once leakage occurs, it will affect the normal operation of manned spacecraft, and even threaten the life safety of astronauts. In order to ensure the sealing performance of manned spacecraft hatch, strict leak detection tests must be carried out before launching. In view of the special structure of manned spacecraft hatch, this paper mainly introduces the leak detection methods for hatch body and frame sealing ring, the whole hatch and the part of hatch. It forms a set of leak detection technology suitable for the whole development process of manned spacecraft hatch, which can meet the leak detection requirements of manned spacecraft hatch, such as Shenzhou spacecraft, space station, lunar module and so on.

As an important component of the helium mass spectrometer leak detector, the geometric parameters of the composite molecular pump not only affect the pumping performance, but also affect the detection performance of the leak detector. Based on the basic theory of molecular pump pumping, this paper establishes the calculation model of composite molecular pump turbine stage. By changing the blade inclination, blade number, blade height and blade thickness, the pumping performance of composite molecular pump turbine stage to air and helium was calculated respectively, and the influence of composite molecular pump turbine stage parameters on the detection performance of helium mass spectrometer leak detector was studied. The results show that reducing the blade inclination, increasing the number of blades, the blade height and blade thickness are conducive to the improvement of the detection sensitivity of the helium mass spectrometer. Considering the pumping performance of molecular pump and the detection sensitivity of helium mass spectrometer, the optimal blade inclination is 25°, the number of turbine blades is between 25 and 30, the blade height is 3 mm, and the blade thickness is 0.6 mm to 0.8 mm.

The intravehicular activity space suit is an important guarantee for astronauts to sustain life in the case of pressure loss in the cabin. The thermal comfort of astronauts is one of the important factors to be considered in the long time pressure loss condition. Based on the lumped parameter method, the thermal model of the spacesuit in the cabin is established, and the human-spacesuit thermal model is established with the Fiala model. The correctness of the simulation is verified by the domestic experimental data. Based on the simulation, the change rules of thermal comfort and humidity of ventilation gas under different pressure loss conditions were obtained, and the system optimization scheme was put forward, which provided reference for the design of emergency cabin pressure protection system and the formulation of life protection scheme in China.

An ultrasensitive leak detection technology applied to high pumping speed automatic exhaust system is designed to solve the problem of small leak detection with leakage rate less than 5×10^-12Pa·m³/s in the process of exhaust and sealing off for traveling wave tube. The device is mainly composed of main vacuum system, external vacuum and baking system, cumulative comparison leak detection system, standard gas flow system and electrical control system. The exhaust table has eight stations, whose limit vacuum reaches ultra-high vacuum without load, and the vacuum furnace can be heated to high temperature. The whole process automation of exhaust process is achieved using program control and possessing functions of automatic collection, storage, analysis and transmission. The standard gas flow system can provide a micro flow from 5×10^-7Pa·m³/s to 5×10^-16Pa·m³/s, and the lower limit of cumulative comparison leak detection system reaches 5×10^-16Pa·m³/s, with a combined standard uncertainty of leak detection results less than 15%.

Transition layer is a key factor to improve the film/substrate relationship and increase the quality of the film. In this paper, the epitaxially grown process of Cr, which is a common transition layer material, was simulated using molecular dynamics method. Surface topography, roughness, radial distribution function and adhesion strength was analyzed to study the effect of incident energy on the film quality. The results show that at the initial stage of deposition, the film/substrate interfacial interaction was the main factor affecting the growth mode of the film. As the incident energy increased, the growth mode changed from Frank-Vander Merve to Volmer-Weber. As the deposition process progressed, the film surface roughness gradually raised during low-energy deposition(15-50eV). However, the opposite trend exhibited during high-energy deposition(75eV) because of the etching effect, and the surface roughness decreased gradually. Meanwhile, the film/substrate interface was destroyed by the shallow injection in the lower energy range, which weakened the film/substrate adhesive strength. Further improving the deposition could improve the film/substrate adhesive effect by forming a composition gradient layer. The research results in this paper shows important guiding significance for the thin film deposition process: increasing the incident energy during the deposition process does not meaning a positive effect, and it must be controlled in a suitable energy range.

Aluminum Oxide (Al₂O₃) barrier films were prepared by plasma enhanced atomic layer deposition (PEALD) at 80℃ with flexible polyethylene terephthalate (PET) as substrate. The test results of X-ray photoelectron spectroscopy and ellipsometer show that the prepared Al₂O₃ films have high purity and good uniformity. Besides, Al₂O₃ films with different thickness were prepared by adjusting the deposition cycle. The effects of film thickness on surface morphology, surface roughness, optical transmission and water vapor transmittance rate (WVTR) were studied. The results show that Al₂O₃ film prepared with 500 deposition cycles exhibits the best performance, with a surface roughness of 1.52nm, an average transmittance (400-1200nm) of 90.4%, and a WVTR of 3.15×10^-3g·m^-2·d^-1.

In order to solve the problem of poor reliability of brazing seal in space environment simulation equipment due to the large installation gap between heat sink and vacuum container, the following methods were adopted. Remove the oxide layer of base metal and solder surface before welding. BAg45CuZn eutectic solder with 45% silver content is selected. The welding heat source with external flame temperature of about 900℃ is used. Heat sink copper pipe and stainless steel pipe with larger wall thickness are selected. The welding gap is controlled in 0.1mm to 0.2mm by welding auxiliary parts. The welding heating time is controlled in 30s. After brazing and sealing of stainless steel pipe and copper pipe with the above processes, the welding test results are good and the welding seam is reliable. Leak detection is carried out by helium mass spectrometer after cyclic impact at low temperature of -186℃ and high temperature of 120℃ on the weld. The leak detection data prove that the sealing performance of the weld meets the use requirements of the equipment.

In order to make better use of the properties of active spectrum control of electrochromic glass and provide theoretical support for the application of electrochromic glass in architecture, the sealed insulating glass unit was taken as an example to discuss the changes of visible light transmittance and shielding coefficient(energy saving effect). It is found that in order to obtain a larger visible light transmittance difference(bleach state minus color state), the key point is to improve the transmittance of electrochromic glass. However, compared with the electrochromic glass with higher cost, it is more realistic to improve the transmittance of Low-E glass.In order to give full play to the energy-saving characteristics of electrochromic glass, the electrochromic glass was placed on the outdoor side and indoor side of insulating glass respectively for testing. The results show that when the electrochromic glass is located on the outdoor side, the change of shielding coefficient is the largest(0.46), which is more suitable for a variety of scenarios. At the same time, the better performance of electrochromic glass film is required.

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.