Thermal expansion in lead zirconate titanate

The volume anomalies with temperature variations in tin-modified lead zirconate titanate ceramics are investigated. Experimental results show that the volume changes are related to the phase transitions induced with temperature. The magnitude and orientation of crystal volume changes are dependent on the particular phase transition. When antiferroelectrics is transformed to ferroelectrics or paraelectrics the volume expands. Oppositely when ferroelectrics is transformed to antiferroelectrics or paraelectrics the volume contracts. In the transition of antiferroelectric orthorhombic structure to tetragonal structure or ferroelectric low-temperature rhombohedral structure to high-temperature rhombohedral structure, there are also revealed apparent anomalies in the curves of thermal expansion. Among them, the volume strain caused by the transition between antiferroelectrics and ferroelectrics is the biggest in magnitude, and the linear expansion dL/L₀ and the expansion coefficient (dL/L ₀)/dT can reach 2.8 × 10⁻³ and 7.5 × 10⁻⁴ K⁻¹ respectively.     

微分脉冲伏安法测定铅(Ⅱ)——组氨酸络合物稳定常数

用微分脉冲伏安法在20℃、C、pH7.70的0.50mol/L NaNO_3支持电解质中测定铅(Ⅱ)—组氨酸络合物,获得了该络合物的一级、二级稳定常数为 logβ1∶5.10±0.02和 logβ2∶8.85±0.02。     

Electrorheological behavior of rare earth-doped barium titanate suspensions

Doping Y, La, Ce into barium titanate is found to be able to improve its electrorheological (ER) effect in DC electrical field. The yield stress of a typical doped barium titanate/silicone oil suspension is approximately 3.2 -*7〗kPa at 3.5 -*7〗kV/mm, which is 10 times larger than that of pure barium titanate/silicone oil suspensions. The ER effect increases with the decrease of ionic radius of rare earth (RE) dopant when RE concentration remains constant, and the suspensions exhibit a relatively high shear stress when Y, La, Ce mole fractions are 15%, 10%～15%, and 5%, respectively. Dielectric measurements show that the suitable doping with RE element increases dielectric loss of barium titanate and causes very marked dielectric relaxation at low frequency. By measuring X-ray diffraction patterns of doped barium titanate, it is considered that the occurrence of lattice distortion or defects may be responsible for the change of dielectric properties which results in the improvement of ER effect of barium titanate in DC electrical field.     

固载化螯合烷基钛酸酯——酯化催化活性及重复性能研究

本文报导了螫合烷基钛酸酯(PSAC—1~#)作为酯化反应催化剂,合成邻苯二甲酸二辛酯;研究了反应转化率与反应时间、反应温度、催化剂用量的关系;讨论了催化剂的重复使用性能及失活原因。     

化妆品中微量毒害元素铅、镉的差分脉冲溶出伏安法分析

利用差分脉冲溶出伏安法测定化妆品中微量毒害元素铅、镉的含量,镉和铅的浓度分别在10-5mol/L～10-9mol/L和10-7mol/L～10-9mol/L范围内峰电流与浓度呈现良好的线性关系,线性相关系数分别为0.9991和0.9992.利用(HNO3-HClO4)混合酸-H2SO4湿式消化法对化妆品样品进行预处理,测定了市场上四种化妆品中的铅和镉,取得满意结果.     

钛酸钠纳米线的合成和结构

利用TiO2粉末和NaOH水溶液在175~240℃水热反应得到了具有层状结构的钛酸钠纳米线。研究了原料比例和反应温度的影响。利用X射线粉末衍射、电子显微术和X射线能量色散谱等结构分析手段研究了纳米线的微观结构。观察到纳米线内部存在大量畴界和缺陷。发现上述钛酸钠纳米线的结构与任何已知结构都不相同,初步标定为单斜结构,单胞参数为a=2.15nm,b=0.377nm,c=1.28nm,β=103.5°。进一步用上述纳米线和KOH溶液水热反应合成了钛酸钾(K2Ti8O17)纳米线。     

铅胁迫对甜高粱种子活力的影响

以重金属铅为胁迫因子，采用纸间发芽的方法，研究了不同浓度的铅溶液对甜高粱品种甜2种子萌发及活力的影响．结果表明，随着处理铅浓度的增加，种子的发芽势、发芽率、根长、芽长、根芽鲜重、根芽干重、发芽指数、活力指数等均呈下降趋势．     

锰、钴掺杂PBSZT压电陶瓷性能的研究

为制备大功率低损耗压电陶瓷材料,对铅基压电陶瓷材料Pb0.9Ba0.05Sr0.05(Sn1/3Nb2/3)0.06(Zn1/3Nb2/3)0.06Ti0.44Zr0.44O3 0.5wt%Sb2O3(质量分数,下同)进行掺杂改性研究,结果表明钴最好的掺杂量为0.3wt%~1.0wt%,此时陶瓷可得到较好的综合性能。0.5wt%锰掺杂可得性能为介电损耗tanδ=0.47%、机械品质因素Qm=2065、机电耦合系数Kp=0.515、压电常数d33=322、介电常数εr=1470。在适量的钴和锰同时掺杂时可得到更低的介电损耗(0.45%)和较好的压电性能,表明同时掺杂可最优地降低介电损耗。     

晶须表面改性及其填充聚醚醚酮摩擦学行为

利用溶胶-凝胶(sol-gel)、氟表面活性剂(FSO)和钛酸酯偶联剂(NDZ-102)等对钛酸钾晶须(PTW)进行了表面改性,对比了改性后水接触角的变化,考察了干摩擦条件下PTW改性对聚醚醚酮(PEEK)复合材料摩擦磨损性能的影响. 利用SEM和光学显微镜观察了磨损面和对偶面转移膜形貌,并分析了其磨损机理. 实验结果表明:改性后PTW的水接触角均有不同程度的提高,FSO改性得最高;改性后PEEK复合材料的摩擦因数均降低,在各载荷下FSO和溶胶-凝胶改性PTW后PEEK复合材料耐磨性明显优于未改性的,300 N载荷下较未改性的分别提高2.64和2.11倍;但是NDZ-102改性却降低了复合材料的耐磨性.     

聚酰亚胺/硅石-钛酸钡纳米复合材料的制备与表征

通过分散聚合法成功地制备了聚酰亚胺/硅石-钛酸钡纳米复合粒子,采用FT-IR、XRD、TEM分析手段研究了复合粒子的结构、形貌及其大小.结果表明,硅石包覆钛酸钡粒子的表面有一层浅色的聚合物,该聚合物包覆层的厚度约为10 nm,并且粒子在外观上基本呈球形或近似球形;同时在包覆过程中BaTiO3纳米粒子的晶体结构稳定,有机相与无机相之间是通过化学键键连.