Wear behaviors of MoSi2 doped with La2O3 against SiC under different loads at 1000 oC in air were investigated by using an XP-5 type high temperature friction and wear tester. The worn surfaces and phases of the sampl...Wear behaviors of MoSi2 doped with La2O3 against SiC under different loads at 1000 oC in air were investigated by using an XP-5 type high temperature friction and wear tester. The worn surfaces and phases of the samples were analyzed by scanning electron microscopy （SEM） and X-ray diffraction, respectively. Results showed that the addition of La2O3 could obviously improve wear resistance of MoSi2. Because of the formation of MoO3 phase on the worn surface, La2O3/MoSi2 composite mainly exhibited oxidation and abrasive wear, which was different from the wear form of MoSi2 such as adhesion, oxidation and abrasion.展开更多
我国是乙型肝炎病毒（hepatitis B virus，HBV）感染高发流行区，虽然预防接种疫苗使得青少年感染率明显下降，但中老年人感染率仍然很高。近年来，戊型肝炎在我国的发病率显著上升。作为戊型肝炎病毒（hapatitis E virus，HEV）感染的...我国是乙型肝炎病毒（hepatitis B virus，HBV）感染高发流行区，虽然预防接种疫苗使得青少年感染率明显下降，但中老年人感染率仍然很高。近年来，戊型肝炎在我国的发病率显著上升。作为戊型肝炎病毒（hapatitis E virus，HEV）感染的特殊人群，老年人戊型肝炎病程长、病情重、预后不佳[1]。老年在感染其他类型的肝炎病毒的基础上更加容易受到HEV的侵犯[2-3]。HBV重叠HEV感染导致肝功能损害严重，肝组织炎症程度高、预后更差[4]，老年人群HBV重叠HEV感染常见。重叠感染者的病情重、病程长、病死率高[5]。老年人常合并有心、脑、肾等基础疾病，更增加了预后的危险性。展开更多
文摘在金属钼表面分别制备了MoSi2涂层和MoSi2/Si3N4涂层,利用SEM和XRD分析研究了涂层的微观结构和物相组成,并比较了涂层在1 450℃大气环境下的抗氧化性能.结果表明:两种涂层与基体结合好且均匀致密;MoSi2涂层钼氧化16 h后出现贯穿裂纹,破坏了SiO2保护膜的连续性,导致涂层失效;Si3N4相的引入可明显改善MoSi2基涂层钼的高温抗氧化性,其抗氧化时间达76 h.
基金supported by the National Natural Science Foundation of China (51071133)
文摘Wear behaviors of MoSi2 doped with La2O3 against SiC under different loads at 1000 oC in air were investigated by using an XP-5 type high temperature friction and wear tester. The worn surfaces and phases of the samples were analyzed by scanning electron microscopy （SEM） and X-ray diffraction, respectively. Results showed that the addition of La2O3 could obviously improve wear resistance of MoSi2. Because of the formation of MoO3 phase on the worn surface, La2O3/MoSi2 composite mainly exhibited oxidation and abrasive wear, which was different from the wear form of MoSi2 such as adhesion, oxidation and abrasion.
文摘我国是乙型肝炎病毒（hepatitis B virus，HBV）感染高发流行区，虽然预防接种疫苗使得青少年感染率明显下降，但中老年人感染率仍然很高。近年来，戊型肝炎在我国的发病率显著上升。作为戊型肝炎病毒（hapatitis E virus，HEV）感染的特殊人群，老年人戊型肝炎病程长、病情重、预后不佳[1]。老年在感染其他类型的肝炎病毒的基础上更加容易受到HEV的侵犯[2-3]。HBV重叠HEV感染导致肝功能损害严重，肝组织炎症程度高、预后更差[4]，老年人群HBV重叠HEV感染常见。重叠感染者的病情重、病程长、病死率高[5]。老年人常合并有心、脑、肾等基础疾病，更增加了预后的危险性。
