Jing CHANG
材料科学技术（英文）
Chitin and chitosan films were prepared by solution casting method. Chitosan specimens used in this study were deacetylated by 56.4%, 69.2%, 85.5% and 96.3%. Their water content, protein adhesion ability, cyto-compatibility, cell adhesion ability, in vitro and vivo degradability and biocompatibility were evaluated. Results indicated that with the degree of deacetylation (DD) between 50% and 70%, the chitosan showed higher water content. The higher the DD, the stronger protein adhesion ability the chitosan had. All the films have good cytocompatibility and the films with higher DD have better cell adhesion ability. Chitin films degraded more rapidly than others, which disappeared in 2 to 4 weeks after they were implanted in subcutaneous tissue and musculature. Their inflammatory reaction became weaker as the films degraded. As the DD got higher, the films degraded slower. The films of DD 85.5% and DD 96.3% even didn0t disappeared in 12 weeks after they were implanted. Their inflammatory reaction was mild at the beginning of degradation, and became severe in 4 to 8 weeks, then weaken at last. This basic result can be very helpful for tissue engineering.
关键词:
Chitosan
,
degree
,
of
,
deacetylation
,
biodegr
叶飞
,
许斐范
,
刘金美
,
谭毅
材料导报
B和O是太阳能级多晶硅中的主要非金属杂质,它们经常以B-O原子对的形式存在.利用第一性原理计算方法,通过对比B-O对在真空、B2 O3和硅中的键合状态,理解Si环境对B-O键合特征的影响.计算结果表明,在这3种原子环境中,O原子的s和p轨道对键合的贡献都比B原子的s和p轨道大得多.其中,在真空中主要是O的2p轨道参与成键,而在氧化物和硅中O原子的2s轨道和2p轨道都参与成键.在硅中,由于B-O间距较大,以及与Si键合导致B-O键合电子态密度的降低,使B-O对在硅中的结合强度低于在氧化物和真空中.
关键词:
第一性原理
,
多晶硅
,
杂质
,
态密度
,
键合
