Gallium nitride(GaN), as the representative of the wide gap semiconductor materials, is one of the important strategic development directions in our country. As an important material growth technology, hydride vapor phase epitax(HVPE) is an effective method for the fabrication of single crystal materials. In this paper, we propose a new flow field and temperature field of HVPE under the condition of stratified flow rate. The results indicate that the reaction precursors can be effectively distributed on the surface of the substrate susceptor when the flow velocity in the outer jet inlets region is three times that in the center region. Finally, HVPE material was grown on the surface of GaN seed crystal on sapphire substrate, and GaN single crystal with average thickness of 20.1 μm and uniformity fluctuation of 6.9% was obtained, which proved that good single crystal film material was grown under theoretical optimization design.

With the introduction of 5G, cloud computing, data center and other concepts, the optical fiber technology not only puts forward the demand of quantity, but also requires the development of optical fiber technology to meet the needs of new applications. Fiber equipment technology is the cornerstone of optical fiber technology, in which plasma equipment technology can realize the development of a variety of large-capacity new optical fiber technology, with a wide range of application prospects and significant research value. Through the relevant simulation, a device based on PCVD fiber precast rod microwave system is designed. The fiber precast rod is successfully manufactured by the device, which proves that the design of microwave system device has a good feasibility. It has certain economic value and development prospects.

Cr/TiN nanoscale multilayers were deposited by arc ion plating with different modulation ratios. The surface morphology, microstructure, hardness and adhesion strength to the substrate of the multilayers were investigated by SEM, AFM, XRD and nano-indenter, respectively. The results show that the Cr/TiN nano-multilayers have compact microstructure with smooth surfaces and comprehensively excellent mechanical properties, indicating nano-interface effects exist in the films. The maximum hardness of 33.22GPa was achieved as the modulation ratio of 2∶3 was applied.

This work aims to study the effects of evaporation rate on refractive index, surface morphology and stress of ZnS films. Electron beam evaporation was used to prepare the ZnS films. Firstly, the film was deposited on K9 substrate and the transmittance curve was tested by spectrophotometer. The refractive index of the film was obtained by spectral inversion method and the surface morphology of the sample was characterized by atomic force microscope. The film was also deposited on PI substrate and the stress of the film was calculated by Stoney formula. With the increase of evaporation rate, the refractive index first increases and then decreases. At the wavelength of 2000 nm, the maximum refractive index was 2.21, and the minimum was 2.07. The higher the evaporation rate, the looser the surface structure of the film sample is. The films prepared at different evaporation rates all show compressive stress. Increasing the evaporation rate can significantly reduce the stress of films. The performance of ZnS film was significantly affected by the evaporation rate. When the rate was 1.5 nm/s, the refractive index can reach the maximum value. When the rate was 2.5 nm/s, the stress can obtain the minimum value.

This article mainly introduces the preparation of four-meter long slot solar vacuum tube-a monomer intermittent coating machine and automatically continuous coating line. We carried out the comparative analysis on the various types of equipment with emphasis on the advantages and disadvantages of the existing problems. It can provide certain reference for the development of other industries coating equipment and design improvement.

According to the basic idea of genetic algorithm and focusing on the field of optical coating, this paper introduced a way to implement genetic algorithm for optical coating designing optimization. This approach included detailed operational steps in “building population” “building fitness function” “selection” “crossover” “mutation”and“elitist strategy”. Based on this method, an optimal design example of implementing 4 passbands in 400-900 nm was given. The result shows that this method can achieve better optimization effect in coating system design. At the end of the paper, we pointed out that this method only realized simple genetic algorithm, and it had a large space for improvement in operation efficiency and optimization ability.

This paper first analyzes the main forms of vacuum precision casting furnace both at home and abroad,and discusses the shortcomings of these forms in the face of large precision casting. Then,in view of these shortcomings,a new structure layout for large vacuum precision casting furnace and its derivative furnace are proposed.Finally,the development opportunity and prospect of this new structure layout are discussed.

With the rapid development of steelmaking technology, vacuum degassing treatment technology has become an effective measure to reduce gas and non-metal impurities in steel, and its key lies in how to obtain vacuum. This article takes one factory′s secondary vacuum treatment of molten steel using a vapour jet pump as an example, which introduces the equipment composition of the vacuum system, expounds the pumping theory of the vacuum pump, and optimizes the pumping performance of the steam jet pump by improving the method while testing. Finally, the vacuum degassing treatment process of molten steel and its effect are given.

With the development of miniaturization,high density and high reliability of microelectronic packaging, various industries have put forward the requirements of high penetration rate,high quality of brazed joints and high cleanliness of materials for brazing technology. High vacuum brazing technology is becoming more and more popular with accelerating development. Such technology ensures the cleanness of vacuum chamber and welding vacuum degree, and then guarantees the welding quality and service life of components. High vacuum brazing technology requires high vacuum and low pressure rise rate. The outgassing of materials at high temperature is the main gas source in the furnace under high vacuum condition, which directly affects the vacuum holding time. In view of the assembled vacuum brazing furnace, the theoretical research and calculation of the outgassing of the furnace material surface and the pressure rise rate of the furnace body are carried out. The vacuum degree and pressure rise rate that vacuum brazing furnace can achieve are tested. The outgassing characteristics of material surface at high temperature are analyzed in detail. The influence of different temperature on the outgassing of materials is analyzed. A model of out gassing pressure rise rate of materials is established, in order to better guide the design of vacuum brazing furnace.

Vacuum refining furnace is a secondary smelting device used for producing high quality molten steel,and the core of which is mechanical vacuum pump system. The long-term stable operation of the system will directly affect the molten steel smelting effect and the cost of steel per ton. Therefore, online monitoring and rapid fault diagnosis of the system are particularly important. In this paper, we take the RH vacuum refining furnace as an example, couple mechanical vacuum pumps at various levels with various monitoring equipment, and introduce remote Internet of Things technology to create a remote fault diagnosis system, which has been verified by a domestic steel plant.

The utilization of thermal compressors is an important way to exceed flexibility transformation of thermal power plants. The extreme ejection ability of thermal compressors is significant for the feasibility evaluation of transformation strategy. The present research conducts theoretical derivation of the related physical process inside the thermal compressor and builds a theoretical model for calculating the maximum entrainment ration. The results show that the present model can describe the ejection ability of the thermal compressor with satisfactory accuracy and application scope. Moreover, the results of the model calculation indicate that the ejection ability is enhanced with the increase of primary and suction steam pressure, but weakened by the increase of compressed steam pressure. The increase of primary steam pressure will promote the increase of entrainment ration while suction steam pressure does not affect the ejection ability.

The storage of metal parts is the basic condition for the microwave vacuum devices. Slow wave components are generally stored in vacuum cabinets. After storage for a period of time, blackening occurs on the copper plating surface of the helix in the slow wave component. The analysis showed that the copper plating on the surface of the helix was vulcanized. Combined with further experimental research and theoretical analysis, the rubber products placed in the vacuum cabinet caused the surface blackening of the copper material. In the vacuum, sulfur is relatively easy to sublimate from the rubber sleeve into the vacuum cabinet, which will diffuse a large amount of sulfur vapor in the vacuum cabinet. These sulfur vapor easily reacts with copper to form Cu₂S, so the sulfur-containing rubber sleeve should not be placed in a vacuum cabinet, and the use of sulfur-containing rubber products in vacuum electronic devices should be prevented from contacting copper parts.

The 60Hz high-frequency cryogenic pellet preparation system was successfully developed with the collaboration of PELIN Laboratory Ltd. It was designed to produce cylindrical cryogenic pellets with diameter of 1.0mm and adjustable length of 1.0mm~1.3mm. The pellets can be injected into the plasma at a frequency within 60Hz with an adjustable speed at 100m/s~300m/s. The engineering commissioning shows that the preparation system meets the design requirements of preparing pellets, and can run stably and reliably. It provides a basis for the physical research of pellet injection on the HL-2A/2M tokamak.

Orbit maintenance, attitude control, damping compensation, formation flight and other tasks of micro-satellites under 200kg put forward clear application requirements for micro-electric propulsion technology and products. Different types of micro-electric propulsion have their own advantages in different power ranges. The scheme and development of LPPT-5 pulse plasma electric propulsion system for 12U standard cubic satellite, LPPT-25 pulse plasma electric propulsion system for 150kg small satellite, LVAT-1 vacuum arc electric propulsion system for 12U standard cubic satellite, LCT-10 colloid electric propulsion system for gravitational wave detection satellite and LHT-40 hall electric propulsion system for low orbit small satellite constellation are discussed in this paper. In the end, the recent progress and future application of LRIT-40 radio frequency ion electric propulsion system and LECR-50 microwave ion electric propulsion system are prospected.

Compared with the traditional fuse additive manufacturing technology based on hot cathode electron beam gun, the fuse additive manufacturing technology based on gas discharge electron beam gun of beam coaxial wire has obvious advantages. In order to shorten the technology gap between the advanced fuse additive manufacturing technology of electron beam in the world, a set of gas discharge electron beam gun of beam coaxial wire with independent intellectual property rights has been developed by analyzing the generation mechanism of gas discharge electron beam gun, and optimizing the cathode and anode parameters that affect the beam quality by using simulation technology. The output electron beam of the gas discharge electron beam gun of beam coaxial wire presents an “X” shape, the droplet transfer mode can be adjusted, and the forming efficiency of the fuse additive manufacturing can reach 5.02kg/h.

In recent years, linear friction welding technology has attracted much attention due to its high efficiency and high quality. This paper briefly introduces the working principle and system composition of linear friction welding,and designs a set of hydraulic vibration servo system according to the practical requirements of welding machine. Firstly, according to the technical parameters of the vibration servo system, the required oil source flow, maximum acceleration, speed and other parameters are calculated. According to the calculation results, the key power components and vibration servo valve in the hydraulic system are then designed and selected. The mathematical model of the friction vibration system is established, and the main parameters are calculated. The mathematical model is simulated, and Bode diagram of the system are drawn. Combined with the simulation results and Bode diagram, the scheme is feasible and can be applied, which provides a reference for future equipment development.