Co-Cu/SiO2催化剂的表征

用溶胶-凝胶法制备了Co-Cu/SiO2系列的担载型催化剂,采用SBET、TPR、XRD、O2滴定等技术对该催化剂进行了研究,并考察了催化剂在F-T合成反应中的催化性能.结果表明,样品的SBET较大,Co和Cu组分均很好分散;Cu2+的加入使得Co更易于被氢气还原,Co是经由Co3+→Co2+→Co0的还原过程,Cu的还原为Cu2+→Cu0;Cu2+的引入使得样品中钴的还原度增大,对F-T合成的催化性能有了一定的改善.     

对甲苯磺酸掺杂聚吡咯的合成、表征及其对金属镁的防腐蚀性能研究

以对甲苯磺酸为掺杂剂, 三氯化铁为氧化剂, 化学氧化吡咯制备了对甲苯磺酸掺杂聚吡咯. 考察了掺杂剂与氧化剂的用量对掺杂聚吡咯电导率的影响, 得到了高电导率聚吡咯的优化条件, 用UV, IR和SEM对其结构和形貌进行了表征. 结果表明, n(对甲苯磺酸)∶n(吡咯)∶n(三氯化铁)＝0.75∶1∶0.5时, 合成的聚吡咯的形貌规则, 电导率达42.7 S•cm^－1. 以聚吡咯为功能成分, 环氧树脂为成膜物质, 得到一种功能膜, 旋涂于金属镁表面, 采用极化曲线和开路电位考察了含有聚吡咯的膜层对金属镁的防腐蚀性能. 结果表明, 含有聚吡咯的膜层对金属镁有很好的防腐蚀性能, 腐蚀电流为0.0981 A, 腐蚀电位为－0.88 V, 在膜层与金属镁之间形成了一层钝化膜.     

聚醚砜酮涂层纤维顶空固相微萃取-气相色谱法分析水中痕量的酚类化合物

应用自制的聚醚砜酮(PPESK,30 μm)涂层纤维,采用顶空固相微萃取-气相色谱法测定水中痕量的酚类化合物。优化了固相微萃取温度、萃取时间、pH值和离子强度。方法的检出限为0.003～0.041 μg/L,相对标准偏差低于16%(n=5)。将PPESK涂层纤维与商品化的聚丙烯酸酯涂层纤维对比,结果表明PPESK萃取酚类化合物有较高的萃取富集倍数。用所制备的PPESK萃取头分析自来水、海水等实际水样,20 μg/L添加水平下的回收率分别为100.5%～111.8%和94.8%～117.3%。     

Natural Compound Curcumin-a Channel Potentiator Rather Than a Corrector of the Defective Intracellular Processing of △F508 Mutant Cystic Fibrosis Transmembrane Conductance Regulator

Cystic fibrosis(CF)is a severe genetic disease caused by the gene mutation of the cystic fibrosis transmembrane conductance regulator(CFTR)chloride channel.The most common point mutation △F508,which leads to impaired intracellular processing and channel gating of CFTR, appears in about 90? patients.The natural compound curcumin was reported to correct the processing defect of △F508-CFTR and proposed as a potential therapeutic drug to cure CF.In the present study.we analyzed the efrect of curcumin on △F508-CFTR and demonstrated that curcumin can restore the impaired chloride conductance of △F508 mutant CFTR.The activity is rapid,reversible and cAMP-dependent.However,we couldn't reproduce the previously reported correction of the defective membrane trafficking of △F508-CFTR by curcumin.Therefore,curcumin may not be a superior lead compound for developing anti-CF drugs.     

基于生物素-亲和素相互作用的胶体晶体阵列的构筑与特性

将胶体晶体阵列(crystalline colloidal arrays,CCA)的Bragg衍射特性与水凝胶的刺激响应性功能结合起来,可制成一种有效的对特定分子具有识别和响应能力的传感材料.采用无皂乳液聚合制备的单分散聚(苯乙烯-4-苯乙烯磺酸钠)纳米颗粒,通过表面电荷的静电斥力可自组装形成CCA,经光聚合固定在水凝胶网络内形成聚合胶体晶阵(polymerized CCA).在水凝胶网络中用共价结合引入生物素分子,通过强的亲和相互作用可与蛋白质亲和素生成生物素-亲和素复合物,在水凝胶网络中形成交联点,引起水凝胶体积相变,进而导致CCA晶面间距发生改变,从而引发Bragg衍射波长发生相应的移动.     

纳米尺度HAp颗粒的制备与表征

通过混合沉积的方式在二甲亚砜(Dimethyl sulfoxide,DMSO)存在下,制备出尺寸分布均一的纳米HAp颗粒.产物通过场发射扫描电子显微镜、粉末X-射线衍射和红外光谱进行了表征.结果表明,HAp颗粒尺寸与溶液中DMSO的体积分数有关,且该类HAp颗粒在溶液中非常稳定.     

高分子溶液壁湍流减阻机理的TRPIV实验研究

利用高时间分辨率粒子图像测速技术(TRPIV)对回流式水槽中低浓度高分子溶液壁湍流的减阻机理进行实验研究。通过对比分析高分子溶液和纯水平板湍流边界层在相同来流速度下的平均速度剖面、湍流强度和雷诺应力,发现高分子溶液的壁面摩擦阻力减小了21.77%,并且其缓冲层增厚,按对数律外移,雷诺应力减小;高分子聚合物主要在近壁区起到抑制湍流脉动的作用,而在主流区的作用不太明显。用流向局部平均多尺度速度结构函数和相干结构条件采样方法,检测并对比了高分子溶液和水的壁湍流相干结构“喷射”和“扫掠”事件中的脉动速度、展向涡量、雷诺应力等物理量的二维拓扑形态,发现高分子溶液近壁区相干结构在猝发时的脉动速度减小,涡量受到抑制,雷诺应力明显减小,说明高分子溶液湍流近壁区相干结构“喷射”和“扫掠”的强度变弱,猝发频率降低,动量和能量的输运减弱,揭示出高分子溶液减阻的重要机理。     

高速铁路连续梁桥的共振响应与振动控制研究

以液体粘滞阻尼器为振动控制外部装置,主桥采用欧拉伯努利梁,通过中国和谐号动车组CRH380AL、日本新干线Shinkansen700和欧洲高速列车HSLMA8三种不同类型的高速列车对比,模拟分析了高速列车作用下桥梁结构共振响应的影响因素,以及粘滞阻尼器的阻尼系数与安装位置对桥梁结构振动响应的减振效果。研究结果表明,（1）合理有效地布置列车荷载轴距,可使桥梁结构发生基频共振的列车时速在运营时速之外,避免了桥梁结构发生较大振动峰值响应,即桥梁结构的基频共振;（2）随着粘滞阻尼器阻尼系数的增大,桥梁的加速度峰值在列车不同时速下均在减少,对桥梁振动有着不同程度的减振效果;（3）通过合理安置液体粘滞阻尼器,可有效降低高速列车作用下桥梁结构的共振响应;（4）随着粘滞阻尼器与主梁的连接点位置逐渐远离支座,粘滞阻尼器的减振效果逐渐明显;（5）随着粘滞阻尼器与桥台的连接点位置逐渐靠近支座,粘滞阻尼器的减振效果略有提升,但不明显。     

A survey on book-embedding of planar graphs

The book-embedding problem arises in several area, such as very large scale integration (VLSI) design and routing multilayer printed circuit boards (PCBs). It can be used into various practical application fields. A book embedding of a graph G is an embedding of its vertices along the spine of a book, and an embedding of its edges to the pages such that edges embedded on the same page do not intersect. The minimum number of pages in which a graph G can be embedded is called the pagenumber or book-thickness of the graph G. It is an important measure of the quality for book-embedding. It is NP-hard to research the pagenumber of book-embedding for a graph G. This paper summarizes the studies on the book-embedding of planar graphs in recent years.     

An attempt to differential Galois theory of second order polynomial system and solvable subgroup of M(o)bius transformations

By introducing the conception "relativistic differential Galois group" for the second order polynomial systems, we establish the relation between the conformal relativistic differential Galois group and the subgroup of M(o)bius transformations, and prove that the system is integrable in the sense of Liouville if its conformal relativistic differential Galois group is solvable with a derived length at most 2. Some omissions on the structures of solvable subgroups of M(o)bius transformations at the first author's article published in this journal in 1996 are refreshed in this paper.