碱性燃料电池聚合物电解质膜的研究

碱性聚合物电解质膜燃料电池(APEMFC)有望摆脱铂基催化剂的限制，其主要挑战是 缺少高离子电导率和化学稳定性的碱性聚合物电解质膜(APEM)。本论文围绕提高APEM 的电导率和稳定性，研究了低温和高温环境下APEM 及离子聚合物，结果如下： ⒈ 以四氟乙烯-全氟烷氧基乙烯基醚共聚物膜为基膜，通过辐射接枝法制备了一种季 铵盐型APEM。APEM 在常温高浓度碱液和60℃去离子水中化学稳定性良好，在60℃时 电导率达到0.05S•cm-1。以APEM 为电解质膜的APEMFC 单体电池在60℃时峰值功率密 度达16mWcm-2。 ⒉ 合成了聚N-乙烯基咪唑鎓盐(QPVIm)，将其与PBI 共混制备了PBI-QPVIm 共混膜。 与PBI/KOH 膜相比，PBI-QPVIm /KOH 膜的离子传导能力显著增强；共混膜在高温(80℃) 碱中的化学稳定性良好；采用QPVIm-PBI/KOH 为电解质膜的APEMFC 单体电池峰值功 率密度大幅提高。 ⒊ 采用辐射接枝法制备了以聚偏氟乙烯为基底的碱性离子聚合物(QPVDF)，将其添 加到催化层中制备的APEMFC 单体电池性能大幅提高，60℃时，峰值功率密度达 4.2mWcm-2。 探索了利用4,4-二氮杂二环[2,2,2]辛烷(DABCO)制备APEMFC 一体化膜电极的方法。 使用DABCO 对氯甲基苯乙烯接枝的PFA 基膜进行季铵化改性，制得离子电导率较高且在 低温下稳定的APEM；使用DABCO 为过渡金属络合物配体制备具有氧还原反应活性的电 催化剂

波分-模分复用/解复用器的设计和性能分析

为了进一步提高通信容量,提出一种基于光子晶体的波分-模分混合复用/解复用器。该器件由4个组合谐振腔、4个波长选择反射微腔以及一对用于模式转换的非对称平行波导组成,通过调节微腔的半径和折射率以及非对称平行波导的宽度和耦合长度实现波分-模分复用和解复用。利用时域有限差分法进行了仿真分析,结果表明,该器件可以实现1 530、1 550nm的TE0模和TE1模4个信道的波分-模分复用和解复用,其插入损耗<0.11dB,信道串扰<-16dB,可以满足现如今大容量光通信系统的要求

fast three-phase clustering algorithm for line segments

针对图像处理获得杂乱边缘线条信息，本文提出了一种新的三步快速线段聚类算法。该算法首先利用线条检测算法对原始图像进行线条检测获得初始线条集合，然后根据这些线段的方向进行粗分类，在此基础上对构成的每个集合内部根据距离差异再进行细分，把距离较远的线段进一步聚类到不同的集合中，最后根据线段之间的邻近关系进行合并和分离，形成最终线段聚类效果。通过试验，与前人工作相比，本文算法效率更高，而且容易实现，所形成的线段聚类能充分反映出目标的结构信息。 For mess lines detected from image processing,this paper presents a new fast line segment clustering algorithm.Firstly we use line segment detector to generate the initial line set from the input original image,then group these lines into different sets according to their directions roughly.Based on these direction sets,each set is further subdivided into different sub-sets according to their relative distances,and then the lines are merged or split on the basis of their neighborhood relations to form the final grouping effects.Compared to previous work,our method is more efficient and easier to be implemented, and the clustered line segments can fully indicate the structure information of targets in the image,which is verified by the experiments

DNA Barcoding for Cephalopoda in classification and phylogeny

应用dnA条形码通用引物扩增了11种中国近海习见头足类(CEPHAlOPOdA)共计97个个体的线粒体细胞色素C氧化酶亚基I(CyTOCHrOME COXIdASEI,COI)基因片段,与gEnbAnk收录的19种95条头足类同源序列进行比对。结果表明,头足类COI基因存在碱基插入缺失现象,杜氏枪乌贼(urOTEuTHIS duVAuCElI)插入缺失位点数多达33个;碱基组成偏倚明显,A+T含量(66.70%)显著高于g+C(33.30%)含量。基于kIMurA双参数模型计算,29个物种的种内平均遗传距离为0.0072,种间平均遗传距离(0.2024)是种内遗传距离的28.11倍。针对剑尖枪乌贼(lOlIgO EdulIS,urOTEuTHIS EdulIS,PHOTOlOlIgO EdulIS)分类和命名的分歧,dnA条形码分类结果显示,该物种与枪乌贼属(lOlIgO)和尾枪乌贼属(urOTEuTHIS)的COI基因同源性较低,不支持将其划归到lOlIgO或urOTEuTHIS。近爱尔斗蛸属(PArElEdOnE)6个代表物种的种间遗传距离较小(0.0120~0.0385),对于此类变异程度较低的物种,dnA条形码仍可准确区分,但其种间遗传距离的阈值尚待深入探讨。系统发育树的聚类分析结果表明,COI基因在种、属水平的分类鉴定及其系统进化关系与传统方法所得结果一致性较高,分别为100%、91.67%;科、目水平的一致性略低,分别为80%和66.67%。可见,线粒体COI基因作为头足类dnA条形码在物种鉴定中适用性较高,亦适用于种属水平的系统进化分析,是形态学分类系统的必要补充和佐证。The mitochondrial cytochrome c oxidase subunit Ⅰ genes (CO I) were sequenced from 97 individuals out of 11 common species of Cephalopoda in China by using the universal barcoding primers.The 97 sequences were compared with the other 95 homologous sequences belonging to 19 species of Cephalopoda obtained from the GenBank.As a result,23.33% of the Cephalopoda species' COI sequences included Insert-Deletion sites.The indels of COI sequences in Uroteuthis duvauceli counted up to 33.The COI sequences of Cephalopoda present the base preference.On average,the content of A+T (66.70%) was significantly higher than that of G+C (33.30%).As calculated by Kimera-2-parameter model,the mean distance pairwise-species and within-species was 0.202 4 and 0.007 2,respectively.The valid name and taxonomy of swordtip squid (Loligo edulis or Uroteuthis edulis or Photololigo edulis) remain controversial or unresolved.Here data gathered using COI genes does not support the assertion that swordtip squid should position in the genera of Loligo and Uroteuthis.In view of the fact that small genetic distance (0.012 0-0.038 5) among 6 species of Pareledone is found,suggesting that the threshold of barcodes (0.02) to identify species be worth furthering studies,particularly for those species with low genetic variation.According to maximum parsimony and neighbor joining trees for all 192 sequences of Cephalopoda,the consistency with morphological classification on both species and genus levels was much higher (100%,91.67%) than that of family or order levels (80%,66.67%).Consequently,providing essential revision and supplement to morphology taxonomy,the COI barcoding is a useful tool for both identification and phylogeny of Cephalopoda.国家自然科学基金项目(40776097;31061160187);公益性行业(农业)科研专项(200903005

Preparation and characterization of radiation-grafted poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) membranes for alkalineanion-exchange membrane fuel cells

Preparation and characterization of radiation-grafted poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) membranes for alkalineanion-exchange membrane fuel cell