Fast-switching phase gratings using in-plane addressed short-pitch polymer stabilized chiral nematic liquid crystals

We demonstrate a fast-switching (sub-millisecond) phase grating based upon a polymer stabilized short-pitch chiral nematic liquid crystal that is electrically addressed using in-plane electric fields. The combination of the short-pitch and the polymer stabilization enables the diffraction pattern to be switched on and off reversibly in 600 μs. Results are presented on the far-field diffraction pattern along with the intensity of the diffraction orders as a function of the applied electric field and the response times. © 2011 American Institute of Physics.

白颊长臂猿染色体的研究

用各种染色体显带技术对云南南部的白颊长臂猿核型进行了详细研究, 并探讨了与其它长臂猿间的亲缘关系及核型进化的可能途径。它的2n=52, 核型公式为44(M或SM)+6(A), xy(M,A)。C带表明一些染色体着丝点C带弱化; 有的染色体出现插入的和端位的C带; X染色体两臂有端位C带, Y染色体是C带阳性和晚复制的。Ag-NORs的数目, 雌体有4个, 雄体有5个, Y染色体上具NOR。对白颊长臂猿与其它长臂猿间的亲缘关系和核型进化的可能途径进行了讨论。

Innovative fabrication of PZT pillar arrays by a colloidal approach

An innovative approach for fabricating pillar arrays for ultrasonic transducer applications is disclosed. It involves the preparation of concentrated piezoelectric lead zirconate titanate (PZT) suspensions in aqueous solutions of epoxy resin and its polymerization upon adding a polyamine based hardener. Zeta potential and rheological measurements revealed that 1wt.% dispersant, 20wt.% of epoxy resin and a hardener/epoxy resin ratio of 0.275mLg -1, were the optimized contents to obtain strong PZT samples with high green strength (35.21±0.39MPa). Excellent ellipsoidal and semi-circle shaped pillar arrays presenting lateral dimensions lower than 10μm and 100μm height were successfully achieved. The organics burning off was conducted at 500°C for 2h at a heating rate of 1°Cmin -1. Sintering was then carried out in the same heating cycle at 1200°C for 1h. The microstructures of the green and sintered ceramics were homogeneous and no large defects could be detected. © 2011 Elsevier Ltd.