Synthesis and fungicidal activity of novel strobilurin analogues containing substituted N-phenylpyrimidin-2-amines

A number of novel strobilurin analogues containing substituted N-phenylpyrimidin-2-amines were synthesized.The structures of these new compounds were confirmed by ~1H NMR,IR and elemental analysis.Biological evaluation in the greenhouse showed several compounds have good fungicidal activities at 25 mg/L.     

Selective 1,3-cycloboronation of enantiopure 1,1,4,4-tetrasubstituted butanetetraols: versatile preparation,structural characterization,and properties of chiral cyclic boron-containing bifunctional Lewis acids

The selective cycloboronation of enantiopure 1,1,4,4-tetrasubstituted butanetetraols was investigated, and a general preparation of chiral cyclic boron-containing bifunctional Lewis acids was discovered. Compounds (2R,3R)- or (2S,3S)-1,1,4,4-tetrasubstituted butanetetraols were reacted with ArB(OH)₂ at reflux in toluene, or THF, or under solvent-free condition to furnish tricoordinated, chiral bicyclo[4.4.0]diboronic esters in high yield via selective 1,3-cycloboronation. Structural characterization and properties of the novel chiral boron compounds are also reported.     

On matching and total domination in graphs

A set M of edges of a graph G is a matching if no two edges in M are incident to the same vertex. A set S of vertices in G is a total dominating set of G if every vertex of G is adjacent to some vertex in S. The matching number is the maximum cardinality of a matching of G, while the total domination number of G is the minimum cardinality of a total dominating set of G. In this paper, we investigate the relationships between the matching and total domination number of a graph. We observe that the total domination number of every claw-free graph with minimum degree at least three is bounded above by its matching number, and we show that every k-regular graph with k?3 has total domination number at most its matching number. In general, we show that no minimum degree is sufficient to guarantee that the matching number and total domination number are comparable.     

椭偏光法研究晶体各向异性光学性质————对KNSBN铁电晶体的应用

本文分析了椭偏光法测量各向异性晶体时入射角和起偏角对测量灵敏度的影响, 着重付论了如何选择合适的实验条件以测量低度各向异性(︱n。-n_e︱< 0.1) 晶体的光学性质. 利用单波长椭偏仪和多波长椭偏谱仪测量了方解石和KNSBN 铁电体样品, 得到各向异性折射率和消光系数值, 与文献有关结果作了比较. 对于︱n。-n_e︱< 0.1 的KNSBN 铁电晶体, 获得了可靠的结果. 关键词：     

强流相对论性电子束在低压中性气体中传输的研究

本文给出了强流相对论性电子束(IREB)在低压中性气体中传输特性的理论和实验研究结果。660kV,40kA,脉宽100ns的电子束注入充有H_2,N_2的漂移管,稳定的传输气压范围在(0.7-6.7)×10~2Pa间,传输效率可达80％以上;极低气压时(P≈13.3Pa)由于空间电荷效应,束电子被虚阴极阻滞并径向发散,不能有效传输;而较高气压时,束电子除受自身电磁场作用及库仑碰撞散射外,等离子体不稳定性使束流传输效率明显降低。用蒙特·卡洛法及数值解析法对电荷中和、电流中和过程进行了模拟计算并解释了实验结果。     

煤基腐植酸对久效磷的增效作用研究

水溶性煤基酸分为从含有水溶性煤基酸的低价煤中抽提得到的水溶性煤基酸和从不含有水溶性煤基酸的低阶煤中氧化得到的水溶性煤基酸。考察了从武川风化煤和霍林河风化褐煤通过两步催化氧化法得到的水溶性煤基酸和从晋城风化煤中得到的水溶性煤基酸对高效、高毒性的杀虫剂--久效磷生物活性的影响。结果表明：（1）三种煤基酸都能增加久效磷的生物活性；（2）所用水溶性煤基酸的理想浓度为0.0025％；（3）根据毒力曲线，久效磷、武川煤基酸-久效磷和霍林河-久效磷的致死中浓度为9.94g/ha，5.99g/ha，6.62g/ha，相对毒力系数分别为：100，165.9，150.2；（4）大田实验结果证实了水溶性煤基酸对久效磷的增效作用。     

Constructions of partitioned difference families

Partitioned difference families (PDFs) arise from constructions of optimum constant composition codes. In this paper, a number of infinite classes of PDFs are constructed, based on known cyclotomic difference families in GF(q). A general approach which obtains PDFs from difference packings and coverings in abelian group is also presented.     

求解非线性规划的原始对偶内点法(英文)

In this paper, we propose a primal-dual interior point method for solving general constrained nonlinear programming problems. To avoid the situation that the algorithm we use may converge to a saddle point or a local maximum, we utilize a merit function to guide the iterates toward a local minimum. Especially, we add the parameter ε to the Newton system when calculating the decrease directions. The global convergence is achieved by the decrease of a merit function. Furthermore, the numerical results confirm that the algorithm can solve this kind of problems in an efficient way.