变导的

Viral vector mainly contain adenovirus, retrovirus,adeno-associated virus and so on, but it has potential danger of safety; it isrepeled by immune system when it is injected to organism for a greatimmunogenicity. An injection with adenovirus vector with highconcentration, it leads to serious inflammatory reaction of liver. Viralvector such as liposome and polycation are commonly used lately. But,liposome and polycation have low specificness and targetness of genetransfer tissue, have lower transfection efficiency and short period ofgene expression, for they can be phagocytized by endothelial system.

许多的载体，病毒载体和非病毒载体以前已广泛应用，病毒载体主要包括腺病毒，逆转录病毒，腺相关病毒等；但病毒载体在安全性方面存在潜在的危险；免疫原性比较强，注射到机体后很快会被机体的免疫系统排斥，当静脉注射高浓度的腺病毒载体会使肝脏发生严重的炎症反应；非病毒载体目前常用的有脂质体及多聚阳离子聚合物；但脂质体和阳离子聚合物介导基因转移缺乏组织的特异性和靶向性，转染效率较低且易被网状内皮系统吞噬，基因表达时间短；因此研制新型的非病毒载体已成为研究的热点，纳米颗粒具有小尺寸效应，表面效应，随着颗粒直径变小，比表面积将会显著增大，故具有很高的化学活性，因而纳米成为了最有应用前景的非病毒载体。

In this paper an innovative method for machining sculptured surfaces is presented. By using a disc cutter with a concave end instead of traditional ball-ended or drum-shaped tools, and adjusting the cut- ted axis to swing relative to the component being machined under some special rules, the envelope formed by the trace of the tool-nose may have the same derivative up to the third order as the required theoretical surface.

本文提出了一种加工自由曲面的新方法，即采用中凹的盘形铣刀取代传统的球头或鼓形铣刀，在每一行程中让刀具轴线相对于工件按特定的规律摆动，使得在垂直于进给方向的法截面中，由刀尖轨迹形成的包络面与理论曲面的法截线具有相同的1～3阶导数，从而在保持精度不变的前提下，使实际行程次数得以大幅度的减少。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。