排序方式: 共有6条查询结果,搜索用时 515 毫秒
1
1.
2.
3.
疫苗佐剂能够增强机体对抗原的免疫应答反应或改变免疫应答反应类型,延长疫苗在体内作用时间,提高疫苗效力。壳聚糖能有效地将疫苗递送到靶抗原递呈细胞或组织,激活抗原提呈细胞,诱导产生免疫应答,促进Th1/Th2应答反应的平衡,因此,壳聚糖作为疫苗佐剂具有一定的潜力。为了解决壳聚糖在中性和碱性溶液中溶解性差,以及进一步提高其黏膜黏附性和靶向性等问题,通过对壳聚糖进行化学改性,生成一系列壳聚糖衍生物,提高其佐剂性能。本论文就近年来有关壳聚糖及其衍生物作为疫苗佐剂和递送系统在疫苗中的应用进行了综述,总结并提出了壳聚糖及其衍生物在疫苗佐剂应用领域所面临的问题以及其未来的发展方向,使读者对其有全面的了解。 相似文献
4.
BaTiO3/ IPNs的制备及介电性能与阻尼性能的相关性 总被引:3,自引:0,他引:3
BaTiO3/ Interpenetrating Polymer Networks (IPNs) composites were prepared by combination of BaTiO3nanocrystal in tetragonal system and polyurethane(PU) / unsaturated polyester (UP) interpenetrating polymer networks (IPNs). The tetragonal nanocrystalline BaTiO3was obtained by hydrothermal process and calcination at 1 200 ℃. The prepared materials were polarized with high voltage and small current, and protected by silicon oil. The morphology of BaTiO3/ IPNs and the effect of combination of BaTiO3on the damping behavior of IPNs were studied. The relationship between damping performance and dielectric charater was also discussed in terms of dielectric constant and dielectric loss measured. The results show that the areas under loss modulus (E″) and the values of loss factors (tanδ) were both increased by combination of BaTiO3into IPNs system. The maximum value of E″ increased above 100 MPa compared with pure IPNs and the extent increased more remarkably after polarizing process. The main and shoulder peak of tanδ curves both moved toward higher temperature ranges, and the temperature ranges of tanδ>0.3 was higher than 100 ℃. Moreover, through polarizing process, the composites exhibited synergistic action caused by elastomeric damping, interfacial abrasive damping and piezoelectric damping mechanisms. The relationship study of damping property and dielectric characters showed that the temperature ranges exhibited excellent consistency of maximum dielectric loss and modulus with damping loss factor. 相似文献
5.
以水热法合成的BaTiO3纤维和同步法制备的互穿聚合物网络为原料,采用原位分散聚合法获得了一系列BaTiO3/(PU/UP-IPNs)复合材料。采用傅立叶交换红外分光光度计跟踪考察了IPNs的聚合过程,用透射电镜观测了IPNs及其复合物的形貌。结果表明,IPNs中两相相畴尺寸在纳米级范围内,在此基础上,实现了BaTiO3纤维状的复合。动态力学性能的检测结果表明,相较纯IPNs,复合材料的阻尼损耗模量和阻尼损耗因子值均有所提高,且在低温区均出现了肩峰。复合物的最大损耗因子值均大于0.4,在约50℃范围内,E’值提高100MPa。力学性能检测结果表明,IPNs中的连续相是决定材料力学性能的主要因素;有机/无机组分间混溶性的降低,使BaTiO3/IPNs复合材料的抗张强度和断裂伸长率均下降。 相似文献
6.
1