FORCE RIPPLE SUPPRESSION TECHNOLOGY FOR LINEAR MOTORS BASED ON BACK PROPAGATION NEURAL NETWORK

Various force disturbances influence the thrust force of linear motors when a linear motor (LM) is running.Among all of force disturbances,the force ripple is the dominant while a linear motor runs in low speed.In order to suppress the force ripple,back propagation(BP) neural network is proposed to learn the function of the force ripple of linear motors,and the acquisition method of training samples is proposed based on a disturbance observer.An off-line BP neural network is used mainly because of its high running efficiency and the real-time requirement of the servo control system of a linear motor.By using the function,the force ripple is on-line compensated according to the position of the LM.The experimental results show that the force ripple is effectively suppressed by the compensation of the BP neural network.

甲下出血34例皮肤镜特征分析

目的 分析甲下出血皮肤镜下特征,探讨皮肤镜在甲色素性疾病鉴别诊断中的应用价值。方法 收集2017年10月-2019年9月在暨南大学附属第一医院皮肤科门诊就诊并行皮肤镜检查的甲下出血患者60例,选取其中有明确外伤史的34例稳定期甲下出血患者并将其分为挤压伤组及砸伤组,统计34例患者共计45处皮损的皮肤镜检查结果,分析其特征。结果 34例患者,男10例,女24例,其中挤压伤稳定期甲下出血25例,观察皮损36处,砸伤导致的稳定期甲下出血9例,观察皮损9处。45处皮损可见均质的红黑色或棕黑色色素沉着斑,30处皮损沿色素斑两端或侧缘有圆形红色、红黑色小球,22处皮损甲两端伴有条纹,31处色素斑周围颜色变淡。挤压伤和砸伤所致甲下出血皮肤镜下表现无明显差异。结论 甲下出血的皮肤镜表现具有一定的特征性,临床上可辅助诊断甲下出血,挤压伤和砸伤所致甲下出血在皮肤镜下表现无差异性特征。

环状肉芽肿并毛囊黏蛋白病1例

患者男,36岁,左侧颈部环状斑块伴痒麻感3个月余。皮损组织病理示:真皮内多处胶原纤维变性灶,其间见黏蛋白沉积,周边淋巴细胞浸润,毛囊见黏蛋白变性;黏蛋白阿辛蓝染色阳性;免疫组织化学:CD3阳性、CD4阳性、CD8及TiA1散在阳性。诊断:环状肉芽肿并发毛囊黏蛋白病。手术切除后无复发。