Pinus massoniana Lamb. was used as the raw cellulose fiber material to investigate effects of ultrasonic wave pretreatment and PFI pretreatment on fiber bonding and absorbability. Influences of ultrasonic wave pretreatment on fiber crystalline structure and hydrogen bonds were also analyzed by wide-angle X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. The absorption and internal bond strength of fiber pretreated by ultrasonic waves increased by 23.49% and 4.07%, respectively, in comparison with those of virgin fiber, which would result in the improvement of weak bonding and absorbability. Instead, when fiber was pretreated by PFI, absorption decreased in comparison with virgin fiber and internal bond strength increased as much as 1.33 times than that of virgin fiber. The analysis of wide-angle X-ray diffraction curves and FTIR spectroscopy curves revealed that the crystallinity of fiber decreased by 20.59% in comparison with that of virgin fiber when treated by ultrasonic waves. Moreover, the effect of ultrasonic wave pretreatment on intramolecular hydrogen bonds was rather stronger than that of intermolecular hydrogen bonds. Therefore, the optimal swelling ability of fiber would be obtained.

Building point clouds classification is an important task for a Smart City. This paper proposes a method based on multi‐scale and multi‐level cloth simulation to classify buildings in airborne LiDAR point clouds. First, the point clouds are preprocessed to denoise, filter ground and normalise height. The height distribution of point clouds in the whole area is then counted. Point clouds are segmented with similar heights on the top of the internal buildings by using the watershed algorithm based on height hierarchical labelling. Finally, the multi‐scale cloth simulation is used to crudely extract the seed points on the top of the buildings. These seed points are grown to realise the complete classification of airborne building point clouds. Multiple sets of data are selected for experimental verification. The results show that this method has higher classification accuracy and better applicability with a correct classification rate of 96.83%, 95.94% and 94.36%, and a recall rate of 98.18%, 96.32% and 92.33% in point level.

Thanks to its unique structure, diamond has many excellent properties, such as high hardness, low birefringence, high thermal conductivity, good chemical stability, etc., but pure diamond has extremely high resistivity (up to 1012 Ω∙m ), which is an insulator, so it is usually doped to expand the application of diamond in the electrochemical field. B atoms have a very small radius, which is an ideal material for doping diamond, and B-doped diamond has good electrical conductivity. In this paper, on the basis of introducing the phase composition and structure of boron-doped diamond (BDD) film, the common methods for preparing BDD film are analyzed, and the application status and prospect of its application in electrochemistry and other fields are summarized.