代铬复合电沉积研究现状与影响因素分析

复合电沉积是一种可用来代替硬铬镀层的表面防护技术。概述了复合电沉积的技术优势,包括绿色环保、成本低廉、操作简单以及镀层性能的自由度大、可控性好等。同时归纳了复合电沉积的颗粒和基质类型,总结了主要性能评价指标和影响因素。在此基础上,重点综述了近年来复合电沉积技术的研究进展,包括复合电沉积机理和颗粒沉积历程。选取了复合颗粒的粒径、晶型、表面状况以及施镀工艺（如电流波形、电流密度、脉冲电流参数、镀液温度、镀液pH、外加力场、热处理等工艺参数）,分别探究各因素对复合电沉积的沉积过程、阴极极化度、镀层形貌、结构、组分、硬度、耐磨性等性能指标的影响,对其中的规律进行了总结。最后展望了复合电沉积技术的发展方向。     

Recognition and segmentation of teeth and mandibular nerve canals in panoramic dental X-rays by Mask RCNN

This study proposes a method based on the instance segmentation algorithm Mask RCNN for recognizing and segmenting 32 teeth and 2 mandibular nerve canals in panoramic dental X-rays. Compared with Faster RCNN, Mask RCNN has an additional semantic segmentation branch, which could directly obtain the position of teeth and the information about mandibular nerve canals in this study. At the same time, Mask RCNN introduces ROI Align, making Mask segmentation more accurate. A total of 120 training sets, 40 validation sets, and 120 test sets were used in the training and testing process. Forty of the test sets were used to test the full-tooth panoramic dental X-rays, and 40 were used for the edentulous panoramic dental X-rays, with 40 for the mandibular canals. The average precision, recall, and F1-score values of the full teeth were 96.59 %, 96.4 %, and 96.5 %, respectively. The P_m value of the defined edentulous panoramic dental X-rays was 95.41 %, and the average precision, recall, and F1-score values of mandibular canals were 76.05 %, 83.70 %, and 78.10 %, respectively. The results showed that the algorithm could effectively identify each tooth, including missing teeth and mandibular nerve canals in panoramic dental X-rays, solving the problem of too many oral structures in panoramic dental X-rays, which makes it difficult to determine the overall oral state. This study will help other researchers promote the research on artificial intelligence-assisted diagnosis in the oral field.