ZST微波陶瓷在介质振荡器上的应用研究

用传统固相法制备ZST(氧化锆-氧化锡-氧化钛)系微波陶瓷,研究了ZST系微波陶瓷的组成对介电性能的影响。通过X-射线衍射(XRD)和HP8714ET网络分析仪对其晶体结构和微波介电性能进行研究,实验结果表明:少量掺Bi2O3的ZST系陶瓷材料可把烧结温度降低至1 260℃,微波介电性能较好;掺入量大于2%(质量分数)时,ZST系微波陶瓷在晶界偏析形成了Bi2Ti2O7新相,微波性能下降。用微波介电性能较好的ZST系陶瓷制成的介质振荡器进行测试,其电性能满足设计要求。     

Application of the stabilization method to interacting resonances

The stabilization method is applied to the case of interacting resonances in the photo-dissociation of van der Waals clusters composed by a rare gas atom bound to a dihalogen molecule. The study of an illustrative two-dimensional model consisting in a T-shaped NeI₂ molecule shows the adequacy of the method whenever the projection of the stabilization wave functions on the assumed prepared initial state is accounted for. The agreement of the fragmentation cross-sections with some previous results using the effective resolvent method and accurate close-coupling calculations is excellent. The method reveals its utility as a complementary tool since allows, through the analysis of the stabilization wave function in terms of zero-order levels, a precise characterization of the resonant states involved. Received 5 April 2002 / Received in final form 24 May 2002 Published online 19 July 2002     

Hopf代数上的扭曲模和(斜)余配对Hopf模

本文第一部分主要把扭曲的方法运用到模上,从而得到扭曲模．作为特例,我们构造了H  M的Smaush模和量子模．当K是有限维Hopf代数,证明K*  M是一个右D(K)-Hopf模,因此得到了一个基本同构定理．第二部分主要把斜余配对双代数进行推广,得到了斜余配对Hopf模,并且给出判断斜余配对Hopf模的一个充要条件．     

Poly(ortho‐phenylene ethynylene)s: Synthetic accessibility and optical properties

Poly(ortho‐phenylene ethynylene)s (PoPEs) have been synthesized via an in situ activation/coupling AB′ polycondensation protocol. The resulting polymers have been characterized by several analytical methods and are shown to have no structural defects. Although the Sonogashira–Hagihara polycondensation reaction is less efficient than for the preparation of the corresponding meta‐ and para‐linked polymers, presumably because of steric hindrance caused by the ortho substituents, the process can be accelerated by the use of microwave irradiation. Optical spectroscopy indicates solvent‐dependent conformational changes between extended transoid and helical cisoid conformations, providing the first experimental evidence for solvophobically driven folding of the PoPE backbone. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1619–1627, 2006     

SDH微波接力通信系统差错性能指标的分配和预测方法

本文根据ＩＴＵ－ＴＧ．８２６建议和ＩＴＵ－Ｒ有关文件，分析了Ｇ．８２６指标在ＳＤＨ微波接力通信系统中的分配方法；提出了ＳＤＨ微波接力通信系统差错性能指标的预测方法；介绍了在ＳＤＨ微波接力通信系统中主要的抗衰落措施及其对差错性能指标的改善效果。     

微波促进下N,N-二甲基甲酰胺中的Knoevenagel反应

在微波促进下，芳醛与丙二腈或氰基乙酸乙酯在DMF中进行Knoevenagel缩合反应，以77％～98％的产率生成相应E-式烯烃。     

微波辐射下苯亚磺酸钠的S-烃基化

在微波辐射下，不用任何有机溶剂和无机载体，苯亚磺酸钠和卤代烃能迅速发生反应生成相应的S-烃基化产物。     

微波辐射下9-芳基-10-对甲苯基多氢吖啶衍生物的合成

芳醛、5,5-二甲基-1，3-环已二酮（达米酮）与对甲基苯胺在以乙二醇为溶剂 ，微波辐射下反应生成一素列新的3，3，6，6-四甲基-1，8-二氧代-9-芳基-10-对 甲基苯基-1，2，3，4，5，6，7，8，9，10-十氢吖啶，产物的结构通过单晶X射线 衍射分析确证。     

纳米Zn-Co铁氧体的固相合成及电磁损耗特性研究

采用NH₄HCO₃与FeCl₃·6H₂O，Zn(NO₃)₂·6H₂O，Co(NO₃)₂·6H₂O进行室温固相反应制得前驱物，经微波加热处理后，进而热分解分别制得复合氧化物ZnFe₂O₄、CoFe₂O₄和Co_0.5Zn_0.5Fe₂O₄。由激光粒度分析仪、XRD和SEM表征：获得了颗粒分布比较均一、平均粒度为65 nm左右、立方晶系尖晶石结构的纳米铁氧体粉体。经测试样品的相对介电常数和相对磁导率后，研究了它们的电磁损耗特性。结果表明：Co_0.5Zn_0.5Fe₂O₄在100～1 800 MHz内比另外两种铁氧体具有更好的电磁损耗特性。