Numerical Study on Effect of Non-uniform CMAS Penetration on TGO Growth and Interface Stress Behavior of APS TBCs

The penetration of CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)is one of the most significant factors that induce the failure of air-plasma-sprayed thermal barrier coatings(APS TBCs).The direct penetration of CMAS changes the thermal/mechanical properties of the top coat(TC)layer,which affects the thermal mismatch stress behavior and the growth of thermally grown oxide(TGO)at the TC/bond coat(BC)interface,thereby resulting in a more complicated interface stress state.In the present study,a two-dimensional global model of APS TBCs with half of the TC layer penetrated by CMAS is established to investigate the effect of non-uniform CMAS penetration on the interface stress behavior.Subsequently,a local model extracted from the global model is established to investigate the effects of interface morphologies and CMAS penetration depth.The results show that non-uniform CMAS penetration causes non-uniform TGO growth in APS TBCs,which consequently causes the stress behavior to vary along the interface.Furthermore,the CMAS pen-etration depth imposes a significant effect on the TC/TGO interface stress behavior,whereas the interface roughness exerts a prominent effect on the stress level at the BC/TGO interface under CMAS penetration.This study reveals the mechanism associated with the effect of non-uniform CMAS penetration on the interface stress behavior in APS TBCSs.

Turner综合征临床研究现状

Turner综合征(TS)是一种罕见的女性性染色体疾病,该病患者常表现为身材矮小、性腺发育不良、先天性心脏病、内分泌紊乱和淋巴水肿等。导致TS患儿死亡的主要原因是并发心血管疾病。嵌合体核型是TS患者常见染色体核型。由于TS患者临床表现差异、染色体核型多样及二者不一致性,增加临床对该病的诊断难度。笔者拟就TS患者相关遗传学与基因组学、常见并发症、诊断和治疗最新研究进展进行阐述,重点介绍嵌合体核型TS患儿的临床表现及诊断,旨在帮助医师进一步认识TS,减少对该病患者的漏诊和误诊。