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Using P.O 42.5 Portland cement as raw material, high-performance foam concrete was prepared by adding plant protein composite cement foaming agent. The influence of the volume ratio of foaming agent and water on the pore size distribution, the unit weight, water absorption, mechanical properties and thermal insulation properties of foam concrete was studied. The results show that with the increase of the volume ratio of foaming agent and water, the pore size of foam concrete increases, the pore shape gradually tends to be round, the integrity of pores increases, the unit weight continues decreasing, and the water absorption continues increasing. When V (foaming agent) :V (water) =4 : 80, the minimum pore shape factor Is 1.351, and the pore shape is closest to spherical. With the increase of the volume ratio of foaming agent and water, the compressive strength and flexural strength of foam concrete first increase and then decrease, and the thermal conductivity first decreases and then increases. When V (foaming agent) :V (water) =4 : 80, the pore size distribution of foam concrete is the most uniform, its compressive strength and flexural strength are the maximum values, respectively 8.16 and 1.29 MPa, and the thermal conductivity is the lowest 0.163 W/(m ⋅ K). The mechanical properties and thermal insulation properties are optimal. [ABSTRACT FROM AUTHOR]

Based on the connotation of green development, SBM-Undesirable model was used to measure the land use efficiency of Lanxi Urban Agglomeration in 2006, 2010, 2014 and 2018, and Theil Index and Spatial Autocorrelation Methods were used to reveal the spatial difference characteristics. The results show that: (1) From 2006 to 2018, the county land use efficiency of Lanxi Urban Agglomeration increased steadily, and the regional differences first expanded and then narrowed. (2) The land use efficiency of counties in Lanxi Urban Agglomeration presents a spatial difference law of “high in the middle-low in the periphery, high in the west and low in the east, and differentiated between the north and the south”, while the two provinces present a decreasing law of “west-east”. (3) The spatial agglomeration characteristics of land use efficiency in Lanxi Urban Agglomeration are remarkable. Locally, the high-high agglomeration is typical in the central region, while the low-low agglomeration spreads from southeast to southwest.

The operation reliability of spacecraft in orbitis affected by the interaction with space plasma, research on the space enviroment by advanced testing method is important. It is costly to carry out research and analysis with space flight. Therefore, tests using ground vacuum environment simulation system are of significance. This paper proposed the structure design, simulation analysis and numerical calculation methods for the three subsystems of plasma environment simulation system, including vacuum vessel, vacuum acquisition and vacuum measurement and control. The simulation results show that the maximum stress of the vacuum vessel is 113.2MPa , and the maximum deformation is 0.59mm , at the same time, vacuum technology index, structural stability and human-machine interaction performance of the system can meet the experimental research requirement.