氮化物颗粒补强石英基复合材料的制备和性能研究

热压制备了氮化物颗粒补强石英基复合材料,研究了氮化物颗粒的引入对石英基复合材料力学性能、介电性能和热学性能的影响．结果说明,氮化物颗粒的引入对石英基复合材料的力学性能有显的补强增韧作用;介电损耗在指标值以内,且随测试温度变化不大;以AlN为第二相的石英基复合材料其临界热震温差在600℃左右,复合引入AlN Si3N4时复合材料的热学性能无明显改善,而复合引入AlN BN使复合材料的临界热震温差提高到1000℃．复合引入AlN BN的石英基复合材料因为有着较好的力学性能、介电性能和热学性能等综合性能而有望用作天线窗材料。     

噻菁感蓝染料的合成及其紫外可见光谱的研究

合成了染料中间体２－甲基－３－磺酸丙基－取代苯并噻唑氢氧化物内盐Ⅰ＿（ａ－ｆ）及２－磺酸丙硫基－３－磺酸丙基苯并噻唑氢氧化物内盐Ⅱ，由Ⅰ与Ⅱ在三乙胺的催化下缩合制得－甲川噻菁染料Ⅲ＿（ａ－ｆ）；初步研究了Ⅲ＿（ａ－ｆ）的结构与其在甲醇中最大吸收的关系。     

LOW-FREQUENCY INTERNAL FRICTION STUDY FOR SrBi2Ta2O9 FERROELECTRIC CERAMICS

Low-frequency internal friction (IF) of SrBi₂Ta₂O₉(SBT) ceramics has been measured at temperatures ranging from 293 to 623 K. Two IF peaks, with their locations around 393 K (P1) and 569 K (P2) (f≈1.58 Hz), respectively, are observed. P1 is found to be associated with a relaxation process with activation energy of 0.97 eV and pre-exponential factor of 3.58×10^-14 s. Peak shape analyses reveal that P1 can be well described by a broadened Debye peak with the width parameter β from 2.70 to 2.92. The mechanism responsible for P1 is proposed to be relaxation of oxygen vacancies near domain walls(DWs). P2 is considered to arise from viscous motion of DWs since it shows characteristics of static hysteresis type. Comparisons for the IF behavior between SBT and Pb(Zr, Ti)O₃(PZT) suggest that in SBT oxygen vacancies are much less localized near DWs than that in PZT. This result provides a possible explanation for the weak DW pinning due to oxygen vacancies in SBT.     

Bi-Pb-Sr-Ca-Cu-O超导体的某些调制结构特征

本文利用高分辨电子显微术对Bi-Pb-Sr-Ca-Cu-O系超导体的显微结构进行了研究。本文发现在2212相中存在两种新的一维调制结构:调制矢量为q=c^*+0.074b~*和D_s=0的调制结构,并发现D_s=0的结构在长时间电子照射下会演变成D_s=1/2ws的稳定结构,同时从倒空间和正空间详细讨论了该体系中的几种调制现象。     

铋钙锶铜氧高温超导体的纳米结构特点

利用X衍射,X能量散射谱(EDS)和高分辨电子显微镜研究了3种Bi-Ca-Sr-Cu-O体系的超导材料及其纳米结构特点。除了具有a=5.41,b=5.44和c=30.8的正交晶胞作为基本结构A₁之外,还发现了3个与钙钛矿结构有关的结构类型:A₀,A₃和A₄。进而,并大量发现一个很显著的结构现象:A₁结构与那些钙钛矿有关的结构(A₀,A₂和A₄)发生共生长。     

3—甲基—2—(取代苯乙烯基)—苯并噻唑碘盐的合成及紫外可见光谱

报道了7种属于半菁染料的苯乙烯噻菁染料的合成及紫外可见光谱研究。发现在甲醇溶液中,取代基对吸收光谱具有一定的影响。     

LOW-FREQUENCY INTERNAL FRICTION STUDY ON MODIFIED LEAD METANIOBATE CERAMICS

Six Q^-1 peaks in freshly-worked PbNb₂O₆ ceramics are observed by low-frequency internal friction measurement so far as we know for the first time. P₁, P₂, and P₄ appear at the first heating process with remarkable shear modulus anomalies. But they are not observed during the cooling process or in the well-annealed samples. Those peaks are considered to be related with the working processes. P₃ is a widened Debye relaxation peak in nature. The activation energy and pre-exponential factor are about 1.01 eV and 2.5×10^-12 s, respectively. This peak is attributed to the interaction of domain walls and oxygen vacancies. P₆ is corresponded with the paraelectric and ferroelectric phase transition. P₅, appearing near T_c, is thought to be caused by the viscous movement of the domain walls.     

菁染料共价键合在单晶硅表面的X－光电子能谱

在单晶硅表面通过多步化学反应共价键合多种菁染料，对它们的ＸＰＳ分析表明，单晶硅表面存在着与各单体染料组成相同的化学元素及化学环境，并由有关元素结合能的分析证明它们是通过硅氮键键合于单晶硅表面上的。     

3—甲基—2—（取代苯乙烯基）—苯并噻唑碘盐的合成及紫…

报道了７种属于半菁染料的苯乙烯噻菁染料的合成及紫外可见光谱研究。发现在甲醇溶液中，取代基对吸收光谱具有一定的影响。