基于Venn图的层次信息可视化

为解决具有层次结构的大量信息的可视化问题,文中给出了用嵌套圆表达树型结构信息的可视化方法,即用相切的圆表示兄弟节点,嵌套的圆表示父子节点,圆的位置、大小和颜色分别表示树节点的不同属性信息.同层的兄弟节点并排排列,圆的排列算法快速、稳定、紧密且不相互重叠,排列圆的个数与时间呈线性关系,该排列算法适于大量信息的可视化,既能快速显示大数据集的整体视图,又方便查看细节信息;既能清楚地表达复杂信息间的层次关系,又能显示树节点的属性.该方法可用于文件系统的可视化,实例表明该方法简单、实用、高效、可靠.

Thermal analysis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) irradiated under vacuum

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was irradiated by Co-60 gamma-rays (doses of 50, 100 and 200kGy) under vacuum. The thermal analysis of control and irradiated PHBV, under vacuum was carried out by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The tensile properties of control and irradiated PHBV were examined by using an Instron tensile testing machine. In the thermal degradation of control and irradiated PHBV, a one-step weight loss was observed. The derivative thermogravimetric curves of control and irradiated PHBV confirmed only one weight-loss step change. The onset degradation temperature (T-o) and the temperature of maximum weight-loss rate (T-p) of control and irradiated PHBV were in line with the heating rate (degreesC min(-1)). T-o and T-p of PHBV decreased with increasing radiation dose at the same heating rate. The DSC results showed that Co-60 gamma-radiation significantly affected the thermal properties of PHBV. With increasing radiation dose, the melting temperature (T-m) of PHBV shifted to a lower value, due to the decrease in crystal size. The tensile strength and fracture strain of the irradiated PHBV decreased, hence indicating an increased brittleness.

2,5-二(2-菲基)-[3,2-b]并二噻吩的合成、表征及在有机薄膜晶体管中的应用

近年来,有机薄膜晶体管(OTFTs)因其成本低、加工简便,特别适用于制备大面积柔性器件而引起人们的广泛关注[1].并苯类化合物和噻吩衍生物是目前最重要的两类高迁移率OTFT材料.由并五苯制备的多晶OTFTs器件迁移率可达到5cm2/(V·s)[2];烷基修饰齐聚噻吩的场致迁移率也可达到非晶硅[0·1~1cm2/(V·s)]的水平[3].但是,这两类材料具有较窄的能隙和较高的最高被占分子轨道(HOMO)能级,容易与空气中的氧气和水发生作用,所制备的器件在空气中衰减较快,并且并苯类化合物对光也非常敏感,限制了其应用范围[4~6].因此,制备稳定的高迁移率有机半导体材料是有机光电子研究领域的重要课题之一.制备稳定的高迁移率有机半导体材料的途径包括用较稳定的芳香基团对噻吩齐聚物进行封端,以增大能隙和降低HOMO能级[7].菲类化合物是并苯类化合物的异构体,具有较好的光稳定性[8].[3,2-b]并二噻吩是一种平面稠环分子,与2,2′-二噻吩相比,HOMO能级相对降低,因而具有相对好的稳定性[9].本文合成了2,5-二(2-菲基)-[3,2-b]并二噻吩(PhTT),表征了其基本的物理和化学性质,制备了相应的有机薄膜晶...

Gas phase derivatization of endohedral metallofullerenes R@C-82 and R-2@C-80 (R = Nd, Ce)

Endohedral metallofullerenes Ce@C-82, Ce-2@C-80, Nd@C-82 and Nd-2@C-80 undergo gas phase ion/molecule reactions with the ion system from self-chemical ionization of vinyl acetate, and exohedral derivatives are thus generated, A new heterocycle is formed from metallofullerenes and a C2H3O+ cation, Endohedral metallofullerenes show much higher reactivities than empty fullerenes during the association and the charge and proton transfer processes, The strong electron-donating character of endohedral metallofullerenes is due to their unique super-atom-like electronic structures. (C) 1997 by John Wiley & Sons, Ltd.

一种新型导电聚合物离子选择电极

有机导电聚合物已成为新材料研究中的重要领域。本文首次用电化学法研制成功了一种检测掺杂阴离子的新型聚吡咯(PPY)导电聚合物离子选择电极。吡咯(PY)的电聚合实验参照文献[5]进行。用恒电流法和