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Objective To investigate the clinical effect of buccal fat pad flaps on the restoration of maxillary defects. Methods Nineteen cases with oral-nasal communications and maxillary soft and hard tissue defects ranging from 3.0 cm×2.0 cm-5.0 cm×4.0 cm after resection of the primary tumor foci were repaired with a pedicled buccal fat pad flap, and the maxillary sinus cavity and oral-nasal communication were closed. The survival, healing and complications of the flap were observed during the 3-month follow-up. Results The buccal fat pad flaps of 19 patients all survived. Five days after the operation, the buccal fat pad flap was dark red with slight edema, and the maxillary defect area collapsed. Ten days after the operation, most of the buccal fat pad flap turned pink, and the collapse was alleviated. One month after the operation, the buccal fat pad flap had no obvious collapse, and its surface was epithelialized, with a shape and color close to those of the normal mucosa. The opening was slightly limited. Three months after the operation, the buccal fat pad flap was completely epithelialized, with no difference from the surrounding tissue, and the opening was approximately 3 transverse fingers. No complications, such as swelling and necrosis of the buccal fat pad flap, limitation of mouth opening, maxillary sinus fistulas, oral-nasal communications and facial changes occurred in 19 patients within 3 months after the operation. Conclusion The application of a buccal fat pad flap has a good effect to repair maxillary tissue defects and close oral maxillary sinus communication with diameters less than 5 cm, so it can be widely used in the clinic.

The general aviation airplane is an important component part of civil airplanes,and its shape feature is of important influence on aircraft drag.The numerical simulation method based on Navier-Stokes equation is utilized to analyze the barrel shape feature of drag polar curve of classical general aviation airplane,and the influence of upper surface outline curvature of fuselage.The aerodynamic characteristics difference for a typical general aviation airplane under three different rear fuselage contractions are studied,including upper surface,lower and side ones.The aerodynamic characteristics of basic shape and improvement shape are compared.The results show that,with the increase of contraction rate,the pressure drag and frictional drag for lower surface and side surface are decreased,while for the upper surface,the pressure drag is increased.The suitable fuselage contraction can reduce the pressure drag of 29.76%,and increase the maximum lift-to-drag of the fuselage of 6.34%.The reasonable contraction pattern can not only increase the lift-drag ratio,but improve the longitudinal static stability as well.

Ceramic 3D printing based on stereolithography has attracted wide attention because it can fabricate complex ceramic components with high dimensional accuracy, good surface finish, uniform microstructure, and excellent mechanical properties. It is one of the important technical means to achieve high-performance parts by additive manufacturing. The core of the technology is to prepare ceramic slurries with high solid loading and good printability, and its composition has a vital influence on the curing effect and printing process. In this review, two main additive manufacturing methods, stereolithography (SL) and digital light processing (DLP), commonly used in ceramic 3D printing were introduced, and advantages and disadvantages of the two methods were compared. Based on the research work in the field of ceramic slurries in recent years, the effects of monomer/oligomer and diluent, dispersant, physical properties of ceramic particles and solid loading on viscosity, shear thinning/thickening behavior, viscoelasticity, yield stress were discussed. Finally, the main development trends and challenges of ceramic slurries via stereolithography were put forward in, and a general guiding principle for the construction of ceramic slurries with high solid loading was provided.