As a type of field emission cathode material, carbon nanotube film shows various of benefits, such as no thermal effect, physico-chemical stability and fast-response, which make it suitable for kinds of vacuum electronics devices. This paper reviews the researches on preparations and applications of carbon nanotubes in Lanzhou Institute of Physics. The experimental method for preparing carbon nanotube films with different micromorphologies by chemical vapor deposition method is summarized. The field emission characteristics of different carbon nanotube cathodes were analyzed. The recent applications of carbon nanotube cathodes in the ultrahigh vacuum measurement instruments and ion thrusters are also introduced.

Carbon nanotube(CNT) field emission cathode has the advantages of quick start, high resolution, long lifetime, and low power consumption. The CNT cathode can be employed in a variety of vacuum electronic devices and components, including flat panel display, vacuum measurement, and vacuum electronic devices. This article discusses major methods for development of carbon nanotube cathode, and emphasizes on direct growth of CNT emitters on catalytic substrate by chemical vapor deposition and substrate anodization with strong adhesion and advantages for applications in the X -ray tube and other vacuum electronic devices. The field emission properties of CNT cathode grown directly on stainless steel substrate are investigated, with the turn -on electric field of 1.46 V/滋m. The high current emission and stability properties of the direct grown CNT emitters are improved significantly comparing with that of the CNT cathode by conventional synthesis on catalytic metal film. The substrate anodization improves clearly the CNT structure and field emission performance. Advantages of large scale production of up to 2 cm in diameter and high current emission of 500 mA/cm2 are also demonstrated.

This paper describes a single vacuum pump operating parameter monitoring system. The system consists of a main master chip STM32F103ZET6 microcontroller and corresponding monitoring sensors. The system's overall design, measurement principles and some key technologies are introduced. The hardware design, software programming, transmission test and other processes are elaborated in detail. The system can acquire and display the operating parameters of the pump, including temperature, pressure, rotating speed and so on. It can also communicate with the PC host computer. The as-designed system is compact in size, low in power consumption, high in reliability and strong in anti -jamming capability, which can effectively realize the real -time monitoring of vacuum pump operating parameters.

In the process of removing tiny metal burrs in the vacuum tube, DC high voltage dedurring has some problems such as removing burr, removing unclean, larger burr residual, and influencing the test of product voltage and frequency. In order to overcome the technical shortcomings of DC high-voltage deburring, high voltage pulse with low repetition rate is used to remove the burr. In order to overcome the complicated design and high cost of the traditional high -voltage pulse power supply with vacuum tube as pulse switch and the whole circuit and control loop of all solid-state high-voltage pulse power supply with semiconductor device as pulse switch, a high voltage low frequency and wide duty ratio based on two transistor forward converter pulse for deburring power supply is developed. Through increasing the number of two transistor forward converters, and dual forward converter, it can meet the wide duty cycle of high voltage output. The design of the main circuit and control loop of the power supply is simple, stable, reliable, expansibility and low cost, which provides a relatively new solution for the design of high -voltage pulse power supply. The experimental results show that the output parameters of the power supply meet the design requirements, and are stable and reliable.

Spacce traveling-wave tube (STWT) are used in a wide variety of areas, such as radar, space technology and electron accelerators. The vacuum is one of the basic conditions for the work of STWT. We use ultra -high vacuum exhaust station to obtain a microwave device with the ultimate vacuum better than 5 伊 10 -9Pa; The residual gases in a macro-wave device during thermal degassing was in-situ monitored with quadrupole mass spectrometer ( QMS ). The major residual gases, including but not limited to H2O, CO, and H2, was investigated. It is shown that 36 hours was economically for the baking exhaust time. The operating principle and method of vacuum leak detection using QMS are introduced, and the leak detection was conducted for macro-wave device experimentally. Satisfactory results were obtained and showed that QMS has so predominant advantage that no leak detector can get over. A test platform for measuring the vacuum of the microwave device has been established. After the STWT sealing off the exhaust equipment, sophisticated, storage and high and low temperature test process of vacuum was tested. When the STWT is sophisticated, the vacuum in the device is reduced by an order of magnitude. After 140h, the vacuum of the device rises to 5.0 伊 10-8 Pa under the ion pump. At this time, the vacuum remained basically unchanged after removing the ion pump. Finally, high and low temperature impact experiments were performed and stored at room temperature for 6 months, the vacuum of the STWT is kept in good. These results provide a good basis for analyzing the quality of the STWT.

This paper focuses on the environmental pollution and management of domestic and international enviroment, based on the engineering experience of polymerization gas recovery and oil & gas recovery, the application characteristics of the water ring pump unit in these different processes was introduced for specific cases under different process conditions. A digital structure model of the water ring compressor was established. The paper investigated the structure parameters formula of water ring vacuum pump under different process parameters, the combination of different process conditions and the materials selection. The development direction of equipment is energy -saving and environment -friendly. It shows that the chemical gases vacuum - compression recovery system has great potential in energy saving and corrosion resistance depend on industry innovation and technological progress.

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

Based on the CFD simulation and an assumption that a tiny gas mass in the lateral of a big accumulation chamber was used to simulate the sampling Xenon, the distributing law under the forced convection condition was studied. The results indicate that, under the forced convection condition, the distributing law absolutely depends on the flow field of the fan built in the big accumulation chamber and the Xenon concentration in the big accumulation chamber can be less than 3% after 220s under forced convection condition. The conclusion here may provide technical support for the operation of the non -vacuum accumulation leak detection method.

The similarity law of the liquid ring compressor performance is the main basis for developing products and expanding their operating ranges. Currently, the study of the similarity law of liquid ring compressor at home and abroad is quite different. The structure, working principle, medium and flow law of liquid ring compressors are very different from those of vane pumps and compressors. The current similar laws cannot be directly used for liquid ring compressor. In this paper, the 2BE1 liquid ring compressors were selected as the research object. The external performance test and statistical regression method were performed. MATLAB fitting function polyfit was used to fit the test data regression. The similar relationships were obtained between the performance parameters such as the suction flowrate and shaft power with the parameters such as the rotational speed and the geometric ratio of the liquid ring compressor, which could provide the basis for the optimum design and application of the liquid ring compressor.

In order to study the spectral reflectance characteristics of the thermal barrier coatings deposited on the surface of turbine blades in aero-engines, the NiCrAlYSi and NiCoCrAlYHf bondcoat of thermal barrier coatings (TBCs) were deposited on the 304 stainless steel substrate by vacuum arc ion plating and the topcoat of YSZ was deposited by EB -PVD. The spectral reflectance of TBCs within a wavelength range of 0.3 to 2.5 μm at room temperature was measured by UV -VIS -NIR spectrophotometer. The results show that no matter which kind of bondcoat is, the reflectance spectra of the NiCrAlYSi/YSZ and NiCoCrAlYHf/YSZ with the same thickness of bondcoat and topcoat are very close in the whole wavelength band. The spectral reflectance of the NiCrAlYSi/YSZ coat shows different characteristics under the topcoat thickness of 20, 100 and 170μm. Within the wavelength range from 0.3 to 0.45 μm, the coating with a 20 μm topcoat shows the strongest reflct ability on purple light, while the other two grayish-white sample show similar ability. Reflectance has a positive relativity to the YSZ thickness in the 0.45 to 2.5 μm wavelength range. Compared with that of the conventional YSZ, the spectral reflectance of micro laminate deposited by modified EB-PVD process is improved by two times.

The anode layer ion source, with simple structure, high beam density and controllable ion energy, can be applied for surface modification especially in large area. It can be also applied for applications of ion beam assisted deposition, thin film etching and surface cleaning. This paper reviews the history and development of anode layer ion source. It introduces the principles of anode layer ion source and research status, discusses its key designs, including the design requirements of magnetic field, electromagnetic field and gas discharge simulation. Finally, it summarizes the applications and future developments of anode layer ion source.

The development status of vacuum arc skull investment casting equipment at home and abroad is described. The application of this kind of equipment and the technical characteristics of equipment development companies in various countries are briefly compared and analyzed. Focusing on the electrical parameter design of the core components of the vacuum arc skull casting equipment, the current density characteristics of different conductive structures are summarized and the special phenomena such as the uneven conduction and distribution of the vacuum arc around the electrode rod and molten pool are discussed and analyzed. Finally, several directions of the development of precision casting technology are introduced.

The wall current probe, as a probe for measuring the longitudinal size and intensity of the bunch, is widely used in the accelerator system. The accelerator vacuum system is an ultra-high vacuum system, and the alumina ceramics are resistant to high temperature with high insulation performance, low outgassing rate and high dielectric strength. Stainless steel is resistant to corrosion, can be baked and has low outgassing rate, which is a common and excellent material for ultra-high vacuum system. This paper introduces the brazing technology of ceramic and Kovar, the argon arc welding structure of Kovar and stainless steel and the helium mass spectrometer leak detection.

To satisfy the special infrared calibration test of large caliber spaceborne remote sensor in space environment, the radiation shielded door was developed. In this paper, functional characteristics and working environment of the radiation shielding door are considered. The material selection, low temperature realization, radiation shielding, solid lubrication and measurement control are analyzed. The successful development of the radiation shielded door has solved the problems of heat radiation interference between the remote sensor, the blackbody and the simulated space environment during the infrared calibration. Meanwhile, accuracy of the infrared calibration is improved. The radiation shielded door with the largest "ultra large radiant surface vacuum calibration blackbody" in our country successfully implemented special large-diameter spaceborne remote sensor infrared calibration test, which marked the large-diameter infrared radiation calibration techniques in our country has reached the world-class level.

Due to memristor's unique electrical characteristics, it has a good prospect in resistive random access memory, artificial neural networks and circuits. The cross -bar was widely used in two -dimensional integration, the three -dimensional integration can be divided into stacked cross -bar array and vertical cross -bar array. The two kinds of three -dimensional structures, models under different mechanisms, window functions and circuit structure were compared and discussed, the method of improving the integration density was analyzed. The memristor's biological synaptic behaviors, application in artificial neural networks and circuits were also introduced.