铋掺杂对铌酸钾钠无铅压电陶瓷结构和性能的影响

用常压烧结法制备铋掺杂铌酸钾钠无铅压电陶瓷(K0.5Na0.5)1-3xBixNbO3(KNBN)。研究不同铋掺杂量对KNN陶瓷结构、形貌、致密度及电学性能的影响。结果表明:在1 120℃烧结的含铋量为1%(摩尔分数)的陶瓷表现出最好的铁电和压电性能及较好的介电性能,即压电常数最大121pC/N,P-E回线形状达到饱和,且剩余极化为12.67μC/cm2,矫顽场Ec为13.58kV/cm,介电常数为575,损耗为5.82%(频率为1kHz)。陶瓷样品在131℃从正交结构转变到四方结构,Curie温度为400℃。     

高炉瓦斯灰的无害化处理及综合利用

韶钢集团公司自１９８８年开始，自选课题，通过５年时间的研究，摸索出了对高炉瓦斯灰进行火法富集—湿法处理的无害化处理工艺，获得了成功，建立了一套完整的活性氧化锌生产线，取得了一定的效益。     

磷酸铋的制备方法及应用进展

磷酸铋具有独特的结构和优异的性能,近年来已成为物理、化学、材料科学等领域的研究热点。综述了磷酸铋各种制备方法的研究进展,如水热合成、溶剂合成、微波合成等。介绍了磷酸铋在光学材料、环境净化等方面的应用。指出开发低成本、易于规模化生产的合成方法,通过改性进一步提高磷酸铋的性能,是磷酸铋未来的研究方向。     

Tunable luminescence from bismuth‐doped phosphate laser glass by engineering photonic glass structure

Because of ultra‐broadband near‐infrared (NIR) emission bismuth‐activated glasses and fibers offer a new promising platform for novel photonic devices such as new type of optical amplifiers and broadly tunable fiber lasers. Yet, challenge remains to manipulate the NIR emission behavior of bismuth (Bi) in photonic glasses for efficient Bismuth‐doped fiber and fiber lasers. Here, by engineering phosphorus and aluminum's topology, broadly tunable NIR emission has been realized in Bismuth‐doped phosphate laser glass. Structural and optical analyses on ²⁷Al magic‐angle spinning nuclear magnetic resonance (MAS NMR), ³¹P MAS NMR, fourier transform infrared (FTIR) and static emission spectra suggest that polymerization of glass network can be improved by proper addition of aluminum into the system, which can be evidenced by partial conversion of Q² to Q³ species of phosphorus and the shift of P–O–P asymmetric stretching vibration toward lower frequency, and this turns out beneficial to Bi NIR emission. Embedding aluminum tetrahedra into phosphorus glass network can reduce the local crystal field around bismuth and therefore lead to the blueshift of Bi emission. This work presents new insights into the luminescent behavior of Bi ions in phosphate glass and it helps the design and fabrication of Bismuth‐doped glasses and fibers in future.     

Enhancement of ultrabroadband Bi NIR emission via fluorination for all wavelength amplification of optical communication

Bismuth (Bi)-doped photonic glasses and fibers with broadband near-infrared (NIR) photoemission have potential applications in tunable lasers and broadband amplifiers. Yet, when it comes to all wavelength amplification of optical communication, it remains challenging to achieve efficient Bi NIR emission in the technically relevant C- and L- bands (1530-1625 nm). Here, we propose a scheme by fluorination triggered enhancement of ultra-broadband Bi NIR emission in nitrided germanate glasses. Besides, compared to previous research, a unique and efficient Bi-activated ultra-wideband NIR emission with new emission bands peaked at ~924 and ~1520 nm under excitation of 450 nm are obtained in nitrided germanate glasses after fluorination. Moreover, the fluorination can modulate the local chemical environment by forcing the conversion of aluminum species from AlO₄ to AlO₅ and AlO₆ and consequently increase the flexibility of the glass network structure, which finally induces the conversion of Bi species and then manipulates the relative emission intensity of different Bi NIR centers. Thus, a flat and tunable emission spectrum covering the entire optical communication band is obtained by optimizing the fluoride amount. We believe this work is helpful to design the Bi-doped tunable fiber lasers and ultra-broadband amplifiers for all wavelength amplification of optical communication.     

Deficient or excessive CuO-TiO2 phase influence on dielectric properties of CaCu3Ti4O12 ceramics

The influence of the CuO–TiO₂ phase (CT) on dielectric properties of the CCTO ceramic was investigated. CaCu_XTi_YO₁₂ (CC_XT_YO) powders were prepared based on the coprecipitated method, where 2.70 ≤ x ≤ 3.30 and 3.25 ≤ y ≤ 4.75. XRD patterns confirmed the presence of CCTO and also the secondary phases as CuO, TiO₂, and CaTiO₃ for each sample and aided in its quantification. Scanning Electron Microscopy (SEM) shows secondary phases evolution in the grain boundaries, and its influence on size and morphology of the grains. Impedance spectroscopy measurements showed that the ceramics with lower amount of CuO and TiO₂ phases (CT/deficient ceramics) exhibited the highest ε′ values (2.1 × 10⁴ at 1 kHz for CC_2.9T_3.75O ceramic). Also, CT/deficient ceramics showed lower tanδ values (0.090 at 1 kHz for CC_2.9T_3.75O ceramic) than ceramics prepared with excessive CuO–TiO₂ phase (0.241 at 1 kHz for CC_3.1T_4.25O ceramics). The deficiency of CuO and TiO₂ phases associated with high percentage of CCTO and CaTiO₃ phases resulted in ceramics with the higher ε′ values.     

水热法制备BiVO_4及其光催化性能研究

采用水热反应法并改变反应条件制备不同形貌和晶体结构的BiVO4可见光催化剂,并探讨不同形貌BiVO4的形成机制及其光催化活性的影响因素。借助X-射线衍射（XRD）、扫描电子显微镜（SEM）及固体紫外-可见漫反射光谱（DRS）对产品进行表征,并在可见光（λ〉420 nm）照射下考察其降解亚甲基蓝（MB）的光催化性能。结果表明,高温更有利于单斜型钒酸铋的生成,反应初始pH值对钒酸铋的形貌影响较大。反应过程中,前驱液中的颗粒通过溶解再结晶、定向聚集自组装、熟化过程最终形成不同形貌的钒酸铋颗粒。钒酸铋的光催化降解速率主要受其晶粒粒径和晶体微观应变的影响,晶粒粒径越大,微观应变越小,结晶度越好,降解速率越高。     

含铋光催化材料的研究进展

含铋光催化材料因其能吸收可见光、催化活性高而具有广阔的应用前景。本文主要回顾了含铋光催化材料近年来的研究概况,详细介绍了铋氧化物、卤氧化铋及钛酸铋、钨酸铋、钒酸铋、钼酸铋、铁酸铋等光催化剂的结构、制备和光催化性能,重点对光催化性能的改进方法进行了综述,包括制备方法的改良、催化剂的掺杂改性及复合催化剂的制备等;最后针对进一步提高光催化剂整体性能、实现工业化应用两点,提出了未来可以利用多元元素掺杂、多元半导体复合进行改性和负载于某些载体制备整体催化剂进行改良的观点。     

SrBi4Ti4O15/Ag复合材料的制备及其介电特性

采用固相烧结工艺制备了SrBi4 Ti4O15(SBTi)/Ag铁电复合材料,用X射线衍射、光学金相显微镜和扫描电子显微镜对材料的组成和微观结构进行了研究,并测量了样品的介电温度谱。结果表明：复合材料是由SBTi和Ag两相组成。金属Ag的加入使SBTi铁电陶瓷的烧结温度从1120℃降低到950℃以下。随着烧结温度的提高,Ag颗粒的尺寸增大,但SBTi晶粒并无明显变化。Ag的加入可以适当提高铁电陶瓷从室温到200℃的介电常数,但对材料的介电损耗影响很小。同时Ag的加入抑制了介电温度曲线介电常数的Curie峰。     

掺钕钛酸铋薄膜的金属有机溶液分解法制备和性能研究

以无机盐为原料 ,采用金属有机溶液分解法在石英衬底上制备了不同钕含量的掺钕钛酸铋 (Bi4 -xNdxTiO1 2 ,BNT)薄膜。用X射线衍射和Raman光谱研究了薄膜的相组成和结构特征 ,用原子力显微镜对薄膜表面形貌和结晶颗粒度大小进行了分析。经过光学透射谱研究得到了薄膜的光学常数。结果表明 :不同钕含量的薄膜经 70 0℃退火处理后 ,都结晶为铋系层状钙钛矿结构 ,薄膜表面平整、无裂纹和空洞 ,颗粒大小为 80～ 10 0nm。Raman光谱分析发现 :当薄膜中钕含量 (x值 )小于 1时 ,钕离子只取代钙钛矿层中A位铋离子 ;而当钕含量超过 1以后 ,Bi2O2 层中的铋离子也被部分取代。透射谱分析得到了Bi3.2 5Nd0 .75Ti3O1 2 薄膜的线性折射率、线性吸收系数和光学带隙分别为 1.92 ,1.98× 10 2cm- 1 和 3 .5 6eV。