共轭聚合物薄膜中光生载流子的产生及输运机制

对共轭聚合物光生载流子的产生机制进行了初步探讨,分析了由最初产生的电子 空穴对经过晶格驰豫之后形成极化子 激子的热离化过程,认为同一链上的激子会迅速复合,只有链间激子对光电流作出贡献.研究了共轭聚合物中载流子的输运机制,导出了共聚物的电导率公式,其计算值与实验结果符合,我们认为是极化子的链间跃迁实现了整个共聚物的电导和光致发光,较好地解释了实验事实.     

Eulerian subgraphs containing given edges

For an integer l0, define to be the family of graphs such that if and only if for any edge subset XE(G) with |X|l, G has a spanning eulerian subgraph H with XE(H). The graphs in are known as supereulerian graphs. Let f(l) be the minimum value of k such that every k-edge-connected graph is in . Jaeger and Catlin independently proved f(0)=4. We shall determine f(l) for all values of l0. Another problem concerning the existence of eulerian subgraphs containing given edges is also discussed, and former results in [J. Graph Theory 1 (1977) 79–84] and [J. Graph Theory 3 (1979) 91–93] are extended.     

Nowhere zero flows in line graphs

Cai an Corneil (Discrete Math. 102 (1992) 103–106), proved that if a graph has a cycle double cover, then its line graph also has a cycle double cover, and that the validity of the cycle double cover conjecture on line graphs would imply the truth of the conjecture in general. In this note we investigate the conditions under which a graph G has a nowhere zero k-flow would imply that L(G), the line graph of G, also has a nowhere zero k-flow. The validity of Tutte's flow conjectures on line graphs would also imply the truth of these conjectures in general.     

过渡金属Schiff碱配合物的研究(Ⅱ)——N-水杨醛甘氨酸三吡啶合镍(Ⅱ)热分解非等温动力学的研究

对由水杨醛及其衍生物所形成的Schiff碱配合物的研究已有不少报道,其中一些配合物具有抑菌、抗癌和抗病毒活性,可作为生物氧载体的模型化合物.     

浸渍法制备钾基半焦在烟气脱硫中的循环再生

采用碳酸钾(K_2CO_3)与活化半焦通过浸渍法制备用于除去烟气SO_2的催化脱硫材料(K/ASC)。研究表明,将活化半焦(ASC)通过10%(质量分数)K_2CO_3改性获得钾基半焦(K10),其在120℃时具有良好的SO_2脱除效率,而且随着再生温度的升高(400～700℃),再生后K10的脱硫活性明显提高。K10(K10-R-600-n)的循环再生测试表明,样品在4次再生循环(K10-R-600-4)后具有最佳的脱硫性能,其硫容量为68.9 mg·g-1,比K10(55.4 mg·g-1)高24.37%。再生分析脱硫产物为物理吸附的SO_2,H_2SO_4和硫酸盐,再生后未分解的硫酸盐沉积会降低样品的脱硫活性。经过10次循环再生(K10-R-600-10),样品的硫容量为初始钾基半焦K10的70%。     

电流密度对锌电积用Pb-Ag平板阳极电化学行为的影响(英文)

研究了在不同电流密度下进行长时间极化后Pb-Ag(0.8%(质量分数,w))平板阳极的阳极电位、腐蚀率及阳极钝化膜.同时,也研究了该阳极在ZnSO4-MnSO4-H2SO4电解液中的阴极电流效率和阴极锌品质.阳极钝化膜的表面形貌用扫描电镜(SEM)进行观测.实验结果表明,不管电解液中是否存在Mn2+,电流密度对阳极和阴极的电化学行为都产生了显著的影响.随着电流密度的升高,阳极电位、腐蚀率、阴极电流效率和阳极泥生成量也增加,而阴极锌中的Pb含量则减少.当电流密度从500A·m-2降到200A·m-2时,阳极在ZnSO4-MnSO4-H2SO4电解液中的稳定电位和腐蚀率分别减少64mV和40%.此外,在比较低的电流密度下,阳极电位更容易稳定,阳极表面生成的钝化膜更加致密并与基体结合牢固,这些都有利于降低阳极腐蚀率.为了降低阳极电位、减小阳极腐蚀率及阳极泥生成量并提高阴极电流效率和阳极锌品质,锌电积的理想工作条件是较低的阳极电流密度和较高的阴极电流密度.     

On (s,t)-supereulerian graphs in locally highly connected graphs

Given two nonnegative integers s and t, a graph G is (s,t)-supereulerian if for any disjoint sets X,Y⊂E(G) with |X|≤s and |Y|≤t, there is a spanning eulerian subgraph H of G that contains X and avoids Y. We prove that if G is connected and locally k-edge-connected, then G is (s,t)-supereulerian, for any pair of nonnegative integers s and t with s+t≤k−1. We further show that if s+t≤k and G is a connected, locally k-edge-connected graph, then for any disjoint sets X,Y⊂E(G) with |X|≤s and |Y≤t, there is a spanning eulerian subgraph H that contains X and avoids Y, if and only if G−Y is not contractible to K₂ or to K_2,l with l odd.     

Ab initio study on phase transition and magnetism of BiFeO3 under pressure

In this paper the first-principles calculations within local spin density approximation (LSDA)+U show that BiFeO3 experiences a mixed phase state with P4mm structure being the intermediate phase before the pressure of phase transition is reached. The critical pressure for the insulator-metal transition (IMT) is found to be about 50 GPa. A pressure induced crossover of high-spin states and low-spin states is observed close to the IMT pressure in R3c structure. The LSDA+U calculations account well for the mechanism of the IMT and crossover of spin states predicted in recent experiment (Ref.[1]).