介孔SBA-15棒负载的Pd3Cl催化剂催化Sonogashira偶联反应（英文）

通过静电吸引策略将具有高度分散性的原子精确纳米团簇[Pd3Cl(PPh2)2(PPh3)3]+(Pd3Cl)负载在介孔SBA-15棒上。结构明确的Pd3Cl/SBA-15催化剂在以水作为溶剂以及温和的反应条件下对催化Sonogashira碳-碳偶联反应展现了较好的催化性能以及循环性。在此基础上,我们研究了Pd3Cl团簇结构与性能之间的关系,并证实内核的Pdδ+(0<δ<2)与配体之间的协同效应是催化反应的关键。     

Effects of mechanical loadings on the performance of a piezoelectric hetero-junction

A fully-coupled model for a piezoelectric hetero-junction subjected to a pair of stresses is proposed by discarding the depletion layer approximation. The effect of mechanical loadings on PN junction performance is discussed in detail. Numerical examples are carried out for a p-Si/ZnO-n hetero-junction under a pair of stresses acting on the ntype ZnO portion near the PN interface, where ZnO has the piezoelectric property while Si is not. It is found that the bottom of conduction band is lowered/raised near the two loading points due to the decrease/increase in the electron potential energy there induced by a tensile-stress mode via sucking in majority-carriers from two outside regions, which implies appearance of a potential barrier and a potential well near two loading points. Furthermore, the barrier height and well depth gradually become large with increasing tensile stress such that more and more electrons/holes are inhaled in loading region from the n-/p-zone, respectively. Conversely, rising/dropping of conduction band bottom is brought out near the two loading points by a compressive-stress mode due to the increase/decrease in the potential energy of electrons by pumping out the majority-carriers from the loading region to the two outside regions. Therefore, a potential well and a potential barrier are induced near the two loading points, such that more and more electrons/holes are driven away from the loading region to the n-zone/p-zone, respectively, with the increasing compressive stress. These effects are important to tune the carrier recombination rate near the PN interface. Thus, the present study possesses great referential significance to piezotronic devices.     

Snap-through path in a bistable dielectric elastomer actuator

The dielectric elastomer (DE) has attracted significant attention due to its desired features, including large deformation, fast response, and high energy density. However, for a DE actuator (DEA) utilizing a snap-through deformation mode, most existing theoretical models fail to predict its deformation path. This paper develops a new finite element method (FEM) based on the three-parameter Gent-Gent model suitable for capturing strain-stiffening behaviors. The simulation results are verified by experiments, indicating that the FEM can accurately characterize the snap-through path of a DE. The method proposed in this paper provides theoretical guidance and inspiration for designing and applying DEs and bistable electroactive actuators.     

CoMoO_4晶须材料的制备及烯烃环氧化催化性能研究

利用Co(CH_3COO)_2、氧化钼、钼酸和咪唑为基础原料,在水热条件下成功制备了CoMoO_4晶须材料.通过元素分析、X-射线衍射、傅里叶变换红外光谱以及扫描电子显微镜等手段对材料的结构和形态进行了表征,证明为完整均匀的CoMoO_4晶须.在环辛烯环氧化催化反应中对材料的催化性能进行了测试,结果证明CoMoO_4晶须具有优良的非均相催化性能.     

Synthesis and Complexation Properties of Novel Chiral Calix[4]-1,3-aza-crown and Calix[4]arene Hydrazone Derivative

<正>Refluxing calix[4]-1,3-substituted benzaldehyde derivative(4) with glycine hydrazide derivative,we obtained a novel calix[4]arene hydrazone derivative(5) via"1+2"condensation in a yield of 78%.In the reaction of compound 4 with L-leucine hydrazide derivative at room temperature,lariat calix[4]-1,3-aza-crown(6) with chiral amino acid group as branched chain was synthesized via"1+1"addition in a yield of 70%.The preliminary extraction experiments suggested that hosting compounds 5 and 6 possessed good complexation abilities forα-amino acids.     

分布式拉曼光纤放大器动态增益控制研究

介绍了动态增益控制的必要性，对动态拉曼传输方程进行了简化，并将其以矩阵形式表示，从而减少了方程的数量，提高了计算速度。由拉曼传输耦合方程推出一种适用于分布式拉曼放大器实时控制的自动控制算法。考虑工程需要，该算法忽略了噪声功率、泵浦间的受激拉曼效应，以及信号和泵浦间受激拉曼效应对泵浦功率的损耗。结果表明该算法能够达到快速抑制输入信号功率突变引起的输出功率／增益波动的目的。     

耗散量子隧道系统中的形变效应与热库维数的关系

本文利用微扰及变分法研究了耗散量子隧道系统中热库声子波函数的形变效应,发现形变与热库的维数有关。随着维数降低,一方面形变效应增大,另一方面形变效应对量子隧道系统的影响变得更为显著。 关键词：     

某些算法时间复杂性的下界

本文定义了两类机器,并讨论了在这两类机器上完成某类作业所需时间的下界。其中包括:在n个排好序的有理数中同时查询n个数至少需时cn log n;把n个有理数按大小排列分类至少需时cn log n,其中c为某个常数。     

NOTES ON GLAISHER＇S CONGRUENCES

Let p be an odd prime and let n≥1,k≥0 and r be integers,denote by Bk the kth Bernoulli number,It is proved that(i) If r≥1 is odd and suppose 1≥r+4,then ∑j=1^p-1 1/(np+j)^r=-(2n+1)r(r+1)/2(r+2)Bp-r-2p^2(mod p^3).(ii)If r≥2 is even and suppose p≥r+3, then p-1∑j=1 1/(np+j)^r=r/r+1Bv-r-1p(mod P^2).(iii) p-1∑j=1 1/(np+j)p-2=-(2n+1)p(mod P^2).This result generalizes the Glaisher‘s congruence. As a corollary, a generalization of the Wolsten-holme‘s theorem is obtained.