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In order to solve the problem that the linear array image of the two-dimensional road surface is easily affected by factors such as illumination changes, shadows, this thesis carried out the research on the design of the intelligent perception system of the three-dimensional information of the highway road surface. This paper first analyzes the design requirements of the intelligent perception system for 3D information on highway pavement, studies the cooperative working mechanism of various high-precision sensors, and proposes a hardware system architecture scheme for 3D information perception of pavement diseases based on multiple sensors. Then, a method of “blocking” classification of road 3D point cloud images based on deep learning network model is proposed. Based on the construction of a small block road point cloud data set, an experimental comparative study is carried out on Pointnet and Pointnet++ networks. The experimental results show that the recognition rate of pavement diseases is better than 86.7% and 90.0%.

This paper describes the development of an X-band pulsed miniature traveling-wave tube (mini-TWT) at the Aerospace Information Research Institute, Chinese Academy of Sciences (AIRCAS). This mini-TWT can produce more than 600-W peak output power and 47.5% minimum overall efficiency over the frequency range of 9 to 10 GHz. It achieves a compact size less than 180mm $(\mathrm{L})\times 30$mm $(\mathrm{W})\times 20$mm (H) and weighs less than 0.3kg.

A risk assessment model based on the D-S evidence theory is proposed to solve problems concerning the security risks of tourism in inland waterways. First, we explain the risk assessment index system and describe the steps for the inland waterway cruise ship navigation safety assessment. Second, we evaluate all indicators at the bottom level and transform them into the distribution of belief items. Finally, we apply the evidential reasoning (ER) approach to merge the belief structure information with the index level, in order to obtain the evaluation indicators. Subsequently, it would be possible for us to obtain the assessment results of the goal level in a comparable way. The evaluation results are presented through a belief assignment form, but it is necessary to transform the distribution information into crisp values for comparison purposes, by using a comprehensive evaluation function. Furthermore, we also conducted a case study on the Lijiaxia reservoir, to present and validate the proposed model and the corresponding methods. The results show that the safety evaluation score of the investigated waterway is 3.06, a value that can be considered to be of an intermediate level. Thus, it can be seen that the risk grade generated from the proposed model tends to be consistent with the real safety state of the waterway.

In order to improve the corrosion maintenance efficiency of grounding grid metal, the corrosion state of underground grounding grid in an 110kV substation was tested and evaluated by the electrical impedance tomography (EIT) technology. Results indicated that the impedance increase ratio of grounding grid branch was in a reasonable range below the warning value, proving the whole ground grid metal had not suffered severe thinning in soil and no breaking had happened in the grounding grid branches. The two-dimension corrosion image of the whole grounding grid was simulated and drawn accurately using the corrosion diagnosis software, with the consideration of the impedance increase ratio of grounding grid branch and the network topology of grounding grid. By realizing the underground grounding grid from the “black-box state” to the “visible state”, EIT technology could be used to evaluate and detect the corrosion degree, corrosion area and corrosion failure of grounding grid rapidly and effectively, which could reduce the blindness of corrosion detection for grounding grid, provide guidelines on the corrosion maintenance of grounding grid and improve the fine management ability of grounding apparatus in substation.

Vibration and Shock from the rocket launch bring high demands for the design of radiation cooled space travelling wave tube. In the paper, dynamic analysis of Ku band radiation cooled space travelling wave tube was carried on by means of finite element analysis method according to environmental conditions. And an optimized prototype was made and tested.

The couplers play an important role in coupling the power in and out from the helical SWS of a TWT with minimum reflection. For a space helix TWT, coupler should be wide bandwidth and small size. The main objective of the paper is to design a wide band output coaxial coupler, and a filter consisting of different radius and different length of transformer section is optimized. The simulated reflection loss of filter transformer section is obtained by using Ansoft HFSS and compares with that of three-stage transformer section. The wide band matching properties of the transformer is better than the three-section transformer section.

In the paper, Influence of interface status (ratio of brazing area and fit clearance) of brazed collector parts on contact heat resistance was theoretically analysised. And by ANSYS simulation, influence of ratio of brazing area and fit clearance on heat dissipation capability of collector for travelling wave tube was studied.

The industry of building materials whose carbon emissions are huge is viewed as an important part in National Economy. Its total energy consumption lags behind the inetallurgical and the chemical, which ranks third. The carbon emissions of building materials were made up of the direct carbon emission and the indirect carbon emission. The carbon emissions of the raw materials and building materials' producing process are the two important parts to evaluate the direct carbon emission. Indirect carbon emission which was generated from the depreciation of equipments and buildings, the management in each link and the environmental process of garbage processing and transportation should be estimated.