Zhang Lan
,
Gao Qin
,
Han Yong
材料科学技术（英）
doi:10.1016/j.jmst.2016.01.008
Micro-porous TiO2 coatings co-doped with Zn2+ and Ag nanoparticles were fabricated on Ti by micro-arc oxidation (MAO) for 0.5, 1.5, 2 and 4?min, respectively. The evolutions of morphology and phase component of the coating as a function of processing time were investigated. The microstructure of the 2?min treated coating was further observed by transmission electron microscopy to explore the coating formation mechanism. The amounts of Ag and Zn released from the 2?min treated coating were measured and the antibacterial properties of the coatings against Staphylococcus aureus (S.?aureus) were also investigated. The obtained results showed that with prolonged MAO time, the contents of Ag and Zn on the coating surfaces increased. All the coatings were micro-porous with pore diameters of 1-4?μm; however, some pores were blocked by deposits on the 4?min treated coating. The 2?min treated coating was composed of amorphous TiO2, anatase, rutile, ZnO, Zn2TiO4 and homogenously distributed Ag nanoparticles. After immersion, Zn2+, Ag+, Ti2+ and Ca2+ were released from the coating and with the immersion time prolonged, the accumulated concentrations of these ions increased. After immersion for 36 weeks, the accumulated Zn2+ and Ag+ concentrations were 6.88 and 0.684?ppm, respectively, which are higher than the minimal inhibitory concentration but much lower than the cytotoxic concentration. Compared with polished Ti control, the coatings co-doped with Zn2+ and Ag nanoparticles significantly inhibited the adhesions of S.?aureus and reduced the amounts of planktonic bacteria in culture medium, indicating that the Zn and Ag co-doped TiO2 could be a bio-adaptable coating for long-lasting anti-microbial performance.
关键词:
Zn
,
Ag nanoparticle
,
Co-doped TiO2
,
Micro-arc oxidation
,
Bio-adaptable
Zhang Yanni
,
Han Yong
,
Zhang Lan
材料科学技术（英）
doi:10.1016/j.jmst.2016.06.007
SrTiO3 nanotube films with good adhesion strengths to Ti substrates were fabricated by using a hybrid approach with a modified anodization and a hydrothermal treatment (HT). The effect of Sr2+ concentration in HT solutions on the morphologies and phase components of the nanotubes were investigated, the SrTiO3 nanotubes formation mechanism was explored, and the adhesion strengths, hydrophilicity and apatite-forming ability of the SrTiO3 nanotubes were also evaluated. The results demonstrated that with increasing the incorporation of Sr2+ into the nanotubes, no obvious changes of the lengths and outer diameters of the nanotubes were observed, but the wall thickness and the crystallinity of SrTiO3 in the nanotubes increased. The accumulation of Sr at the inner tube wall indicated that the reaction of Sr2+ with TiO2 mainly occurred in the vicinity of internal surfaces of the closely arranged nanotubes. The formation of the SrTiO3 nanotubes could be attributed to an in situ dissolution-recrystallization process. The SrTiO3 nanotubes exhibited good hydrophilicity and bioactivity, and the induced apatite preferred to nucleate on the nanotubes with higher crystallinity and Sr content, indicating a good bio-adaptability of the SrTiO3 nanotubes for orthopedic application.
关键词:
SrTiO3 nanotubes
,
Modified anodization
,
Hydrothermal treatment
,
Bio-adaptability
郑桂丽
,
姜丽
,
张志东
液晶与显示
doi:10.3969/j.issn.1007-2780.2010.06.001
根据Erickson-Leslie流体动力学理论,研究了混合排列向列相-共面转换液晶盒的引流效应.在强锚定边界条件下,经过理论推导,得出液晶指向矢与流速的关系方程,进一步通过数值计算得出指向矢分布与时间的关系.发现引流效应加快了指向矢达到平衡态的速度,而且破坏了指向矢分布的瞬态对称性,特别在加电压的初始几毫秒这种现象非常明显.
关键词:
混合排列向列相
,
共面转换
,
引流效应
,
指向矢分布
余永刚
,
王玉强
,
周彦煌
,
陆欣
工程热物理学报
为了探索液体火箭发动机的新型点火方法,设计了一种周期性序列脉冲放电火花的模拟点火装置,该装置采用电机驱动电极转动,在圆周上形成放电火花的时空分布.采用高速录像系统,开展了HAN基液体推进剂LP1846液雾在不同条件下电点火特性的实验研究,结果表明,电极转速在3-5 r/s时,电火花在圆周放电空间内的分布比较密集,电能时空分布比较均匀,LP1846液雾点火效果较好.喷雾场流速、液雾细度与周向放电火花能量分布存在一个最佳匹配关系.
关键词:
液体推进剂
,
喷雾
,
电点火
,
瞬态测量
钱晨
,
杨斌
,
章于川
,
夏茹
,
钱家盛
高分子材料科学与工程
通过动态流变学方法研究了不同配比下聚丙烯/乙烯-丙烯-二烯三元共聚物(PP/EPDM)共混体系相分离行为.结果表明,EPDM与PP相容性不佳,当EPDM质量分数达到20％即已发生相分离,在质量分数为50％时形成双连续相结构,在质量分数50％～60％时发生相反转.采用Cole-Cole曲线、Han曲线、van Gurp曲线等方法表征了PP/EPDM体系相分离行为,其中van Gurp曲线最为敏感.
关键词:
聚乙烯
,
三元乙丙橡胶
,
共混
,
动态流变行为
,
相分离
李艳梅
,
白露
,
王宇
,
杨伟
,
杨鸣波
高分子材料科学与工程
将少量超高分子量聚乙烯(UHMWPE)引入高密度聚乙烯(HDPE)构成共混体系,考察了共混物的动态流变行为随组成、温度、频率的变化规律.研究结果表明,体系储能模量、损耗模量、复数黏度随UHMPWE含量增加而增大;Han曲线斜率均小于2且不存在温度依赖性;Cole-Cole曲线均呈半弧形未表现出相分离特征,说明共混体系在熔体状态下并未发生分相过程;所有试样的时温叠加(TTS)主曲线在低频区并未出现特殊的粘弹松弛行为,而在高频区随着UHMWPE含量增加,时温叠加原理失效现象更加显著.
关键词:
高密度聚乙烯
,
超高分子量聚乙烯
,
共混
,
动态流变行为
