纤维束张紧力缠绕复合材料飞轮的预应力简化分析

在纤维束缠绕时施加张紧力，使得固化成型后的飞轮内部形成一定的预加径向压应力，这是提高飞轮径向强度的有效方法之一。基于过盈配合的思想建立了计算张紧力缠绕导致的复合材料飞轮内部预应力和变形的简化模型和方法。通过算例分析发现：等张力缠绕产生的环向应力在半径方向上先减小后增大，径向压力应力不断变小；变张力缠绕过程中，张紧力由小逐渐变大时，飞轮的径向压应力增大，径向强度提高；飞轮设计中仅仅依靠张紧力缠绕是不够的，还必须和固化成型后的厚壁筒之间的过盈套装一起来设计合理的径向预加压应力。

Multi-armed poly(L-glutamic acid)-graft-oligoethylenimine copolymers as efficient nonviral gene delivery vectors

Background The application of polyethylenimine (PEI) in gene delivery has been severely limited by significant cytotoxicity that results from a nondegradable methylene backbone and high cationic charge density. It is therefore necessary to develop novel biodegradable PEI derivates for low-toxic, highly efficient gene delivery.Methods A series of novel cationic copolymers with various charge density were designed and synthesized by grafting different kinds of oligoethylenimine (OEI) onto a determinate multi-armed poly(L-glutamic acid) backbone. The molecular structures of multi-armed poly(L-glutamic acid)-graft-OEI (MP-g-OEI) copolymers were characterized using nuclear magnetic resonance, viscosimetry and gel permeation chromatography. Moreover, the MP-g-OEI/DNA complexes were measured by a gel retardation assay, dynamic light scattering and atomic force microscopy to determine DNA binding ability, particle size, zeta potential, complex formation and shape, respectively. MP-g-OEI copolymers were also evaluated in Chinese hamster ovary and human embryonic kidney-293 cells for their cytotoxicity and transfection efficiency.

三碘-氯化四-(4-三甲基苯胺基)卟啉-羟基-水合锰水合物的合成与晶体结构

报道了标题化合物([Mn(Ⅲ)OH·H_2O·TMAP]·I_3·Cl·9H_2O)的合成和晶体结构。晶体属P2_(1/a)空间群,a=1.8502(1)nm,b=1.2738(1)nm,c=3.0458(2)nm,β=104.52(4)°,Z=4,R=0.096,R_w=0.087.用顺磁和光谱电化学证明卟啉配合物中心锰为三价,确定了锰卟啉轴向两个配位氧原子,一个属水分子,另一个属氢氧根。讨论了锰卟啉的稳定氧化态。