Naβ〃－Al_2O_3与水的作用

本文借助Ｘ射线衍射物相分析和热分析对Ｍｇ或Ｌｉ稳定的Ｎａβ＂－Ａｌ２Ｏ３粉体和陶瓷在不同温度条件下与水发生的作用进行了系统地研究．实验表明，在密闭的常温条件下水主要以分子形式进入Ｎａβ＂－Ａｌ２Ｏ３的传导层内，形成水合物Ｎａβ＂－Ａｌ２Ｏ３·Ｈ２Ｏ；随着温度的升高，在β＂－Ａｌ２Ｏ３中将发生Ｈ３Ｏ＋与Ｎａ＋之间的离子交换，生成（Ｎａ＋，Ｈ３Ｏ＋）β＂－Ａｌ２Ｏ３·Ｈ２Ｏ；当温度进一步提高至２５０℃时，β＂－Ａｌ２Ｏ３结构明显地分解，产生一系列氢氧化物，通常离子交换和分解速度较慢，在短时间内仅局限于陶瓷的表面．研究认为，水合化的β＂－Ａｌ２Ｏ３对泥浆中的游离Ｎａ＋离子具有束缚作用．     

Naβ‘’—AlO3与水的作用

本文借用了Ｘ射线衍射相分析和热分析Ｍｇ或Ｌｉ稳定的Ｎａβ－Ａｌ２Ｏ３粉体和陶瓷在不同温度条件下与水发生的作用进行了系统地研究。实验表明，在密闭的常温条件下水主要以分子形式进入Ｎａβ－Ａｌ２Ｏ３的传导层内，形成水合物Ｎａβ－Ａｌ２Ｏ３．Ｈ２Ｏ；随着温度的升高，在β－Ａｌ２Ｏ３中将发生Ｈ３Ｏ＾＋与Ｎａ＾＋之间的离子交换，生成（Ｎａ＾＋，Ｈ３Ｏ＾＋）β－Ａｌ２Ｏ３．Ｈ２Ｏ；当温度进一步提高至２５０℃时，     

Li1+2x+yAlxNdyTi2-x-ySixP3-xO12系统的锂快离子导体研究

Ｌｉ１＋２ｘ＋ｙＡｌｘＮｄｙＴｉ２－ｘ－ｙＳｉｘＰ３－ｘＯ１２锂快离子导体可以用精选的天然高岭石Ａｌ４「Ｓｉ４Ｏ１０」（ＯＨ）８为起始原料，经与Ｌｉ２Ｃｏ３、ＴｉＯ２、ＮＨ４Ｈ２ＰＯ４进行高温（８００－１０００℃固相反应约２０ｈ而制得，一个空间群属于Ｒ３Ｃ的固溶体导电相可在ｙ＝０．５，ｘ≤０．３和ｙ＝１．０，ｘ≤０．４的组成范围内发现，该盯具有较好的电导性较低的活化能，起始组成ｙ＝１．０，ｘ＝０．     

以高岭石和NaTi2（PO4）3为基的钠快离子导体

本文以高岭石为起始原料、以ＮａＴｉ２（ＰＯ４）３为母体结构，通过高温固相反应合成快离子导体Ｎａ１＋２ｘＡｌｘＴｉ２－ｘＳｉｘＰ３－ｘＯ１２系统，并研究了此系统的相组成、结构和电性能．大多数合成反应在１０７３～１２２３Ｋ下完成．在。ｘ＜０．６的组成范围内可形成具有ＮＡＳＩＣＯＮ结构、空间群为Ｃ２／ｃ的固溶体·ｘ射线粉末衍射分析表明随。的增大，系统各合成物的晶胞参数增大．ｘ＝０．４的合成物具有最好的离子电导率，６７３Ｋ时达３．００×１０－３Ｓ／ｃｍ，而激活能为３６．０２ｋＪ／ｍｏｌ．     

Na2O在Al（OH）3颗粒中的赋存状态及煅烧过程的行为

Ｎａ２Ｏ是非冶金级Ａｌ２Ｏ３的重要技术指标，本文应用Ｄ／ＭＡＸ－３ＢＸ射线衍射，ＩＲ－４４０红外光谱，化学物相分析等方法研究了赋存于氧化铝水合物中的Ｎａ２Ｏ在煅烧过程中行为β－Ｎａ２Ｏ．Ａｌ２Ｏ３随温度升高而分解，最终是αＡｌ２Ｏ３与Ｎａ２Ｏ．１１Ａｌ２Ｏ３共存，氧化铝水合物的Ｎａ２Ｏ含量增加，煅烧产品的α－Ａｌ２Ｏ３含量减少，比表面降低，研究结果对生产及应用Ａｌ２Ｏ３的行业均有益。     

纳米ZrO2/(1-n)SiO2-nAl2O3介孔复合作的制备与光致发光

采用溶胶－凝胶法和超临界干燥技术制备了（１－ｎ）ＳｉＯ２－ｎＡｌ２Ｏ３（ｎ＝０、０．０１、０．１）混合气凝胶体系，并以此作为载体，成功地将纳米ＺｒＯ２粒子组装到（１－ｎ）ＳｉＯ２－ｎＡｌ２Ｏ３介孔体系中，而形成纳米ＺｒＯ２／（１－ｎ）ＳｉＯ２－ｎＡｌ２Ｏ３介孔复合材料。光致发光光谱研究表明，室温下以３１６ｎｍ（３．９２ｅＶ）波长激发时，纳米ＺｒＯ２粒子５４０ｎｍ（２．３０ｅＶ）荧光峰，在介孔复合体     

立方A^4＋M^5＋2O7型化合物与新型负热膨胀材料

概述了立方Ａ＾４＋Ｍ＾５＋２Ｏ７型化合物的结构特点，讨论了ＡＶ２－ｘＰｘＯ７型（Ａ＝Ｚｒ或Ｈｆ；ｘ＝０．１～１．２）及其部分取代的Ａ＾４＋１－ｙＢ＾４＋ｙＶ２－ｘＰｘＯ７型（Ｂ＝Ｔｉ，Ｃｅ，Ｔｈ，Ｕ，Ｍｏ，Ｐｔ，Ｐｂ，Ｓｎ，Ｇｅ或Ｓｉ；ｙ＝０．１～０．４）和Ａ＾４＋１－ｙＣ＾１＋ｙＤ＾３＋ｙＶ２－ｘＰｘＯ７型（Ｃ为碱金属元素，Ｄ为稀土金属元素）材料的负热膨胀性能。     

溶胶—凝胶法合成Li2＋xBxSi1—xO3及其离子导电性能的研究

用溶胶－凝胶法合成了Ｌｉ２＋ｘＢｘＳｉ１－ｘＯ３（ｘ＝０－０．５）,发现形成固溶体的范围是０〈ｘ≤０．２。对其离子导电性的研究发现,当ｘ＝０．３时出现电导率极大值。     

锂快离子导体Li_(1 2x y)Al_xYb_yTi_(2-x-y)Si_xP_(3-x)O_(12)系统的研究

以ＬｉＴｉ２（ＰＯ４）３为基以天然高岭石为起始原料,经高温固相反应（９５０～１１５０℃）制得了 一系列锂快离子导体材料Ｌｉ１＋２ｘ＋ｙＡｌｘＹｂｙＴｉ２－ｘ－ｙＳｉｘＰ３－ｘＯ１２（以下简称Ａｌ－Ｙｂ－Ｌｉｓｉｃｏｎ）．系统 的合成温度随ｘ和ｙ值的增大而降低．应用交流阻抗技术测定的电导率数据结果表明ｙ＝０．３, ｘ＝０．１的合成物的电导率最好,４００℃时电导率达２．４５×１０－２Ｓ／ｃｍ, ２００～４００℃内的电导激 活能为３８．３ｋＪ／ｍｏｌ．ＸＲＤ分析结果表明在ｙ＝０．３,ｘ≤０４及ｙ＝０．５,ｘ≤０．３的组成范围内 均能得到空间群为Ｒ３ｃ的合成物．     

Na掺杂对MTG-YBCO临界电流密度特性的影响

本文研究了Ｎａ掺杂对ＭＴＧ－ＹＢＣＯ（ＹＢａ２－ｘＮａｘＣｕ３Ｏｙ＋４０ｍｏｌ％Ｙ２ＢａＣｕＯ５ｘ＝０．０、０．１、０．２）生长织构及其超导性能的影响。适量Ｎａ的掺入有利于ＭＴＧ－ＹＢＣＯ沿（ａｂ）面的生长,改善晶体生长的宏观形貌。同时,掺Ｎａ后ＭＴＧ－ＹＢＣＯ试样的Ｔｃ,ｏｎ变化不大,但Ｔｃ,ｏｆｆ随掺杂量ｘ的增加而降低,即超导转变宽度△Ｔ增大。适量Ｎａ掺杂改善了ＭＴＧ－ＹＢＣＯ的临界电流密度特     

Eu2+在多铝酸钠体系中的发光

应用高温固相法合成了Na的多铝酸盐,并研究了Eu^2＋在体系中的发光性能．结果表明,Na_1＋xMgAl_11－xO₁₇体系在整个组成范围内保持Na的β－Al₂O₃结构不变,而对于Na_1．67－2xBa_xAl1_0．33O₁₇体系,在x＝0．30附近体系结构发生转变,x＜0．30,体系形成Na的外β－Al2O3结构的固溶体,x＞0．30,体系形成Ba的β－Al₂O₃结构的有序体;与体系组成和结构的变化相对应,Eu^2＋的发射能量和发光强度产生相应的变化,在Na的β－Al₂O₃中Eu^2＋存在高、低能两种发射中心;通过系列化研究,获得了新的组成的、具有β－Al₂O₃结构的荧光体Na_0．67Ba_0．50Mg_0．67Al_10．33O₁₇：Eu^2＋,在较低的掺杂浓度（0．05mol）下可以产生较强的发光．     

Hydrothermal synthesis and photoluminescence of Eu(2-x)Sm(x)Sn2O7 (x = 0-2.0) nanophosphors

Eu(2-x)Sm(x)Sn2O7 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0) solid solutions were successfully synthesized by a simple, mild hydrothermal process. The crystal structure, particle size, and chemical composition of the solid solutions were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. X-ray diffraction patterns and transmission electron microscopy images reveal that all the products were cubic pyrochlore-type Eu(2-x)Sm(x)Sn2O7 nanocrystals with the diameter of approximately 20 nm. Due to efficient energy transfer from Sm3+ to Eu3+, the Eu(2-x)Sm(x)Sn2O7 (x = 0.1, 0.5, 1.0, and 1.5) nanocrystals exhibited strong 5D0 --> 7F1 photoluminescence emission of Eu3+. The dominant 5D0 --> 7F1 transition revealed good monochromaticity and low distortion of the Eu(2-x)Sm(x)Sn2O7 nanophosphors.     

The effects of Mn2+ doping on the luminescence properties of 12CaO 7Al2O:Eu2+ nanocrystal phosphor

The long lasting blue phosphorescence (LLP) and photostimulated luminescence (PSL) after ultraviolet light irradiation at room temperature in 12CaO 7Al2O3:xEu2+, yMn2+ (x = 0, 0.001; y = 0, 0.01) prepared by the chemical co-precipitation method were observed. It was shown that novel oxide 12CaO 7Al2O3:Eu2+, Mn2+ (C12A7:Eu2+, Mn2+) with unique nanocage structure can store energy when irradiated with 365 nm photons. And photon energy can be subsequently released by exposed to 980 nm light. The codopant Mn2+ enhances the intensity of the persistent phosphorescence and PSL due to the existence of more shallow and new deeper electron traps in C12A7: Eu2+, Mn2+. A model for energy storing and recovering and the detailed mechanism of PSL are presented through comparing with the luminescence properties of the co-doped C12A7:Eu2+, Mn2+ and C12A7:Eu2+.     

Ca10K（PO4）7:Eu3+红色荧光粉的制备及其发光性质

高温固相法合成了Ca10-xK(PO4)7:xEu3+(x=0.02,0.04,0.06,0.08,0.10,0.12,0.14和0.16)的红色荧光粉。X射线衍射表明,样品具有标准的Ca10K(PO4)7六角晶体结构,且无第二相存在。在393nm的波长激发下,样品获得由Eu3+的4f-4f跃迁产生红光发射,其中以613nm附近的5 D0→7F2电偶极跃迁发射为最强。通过调节Eu3+的掺杂浓度,获得了色坐标与商业化Y2O2S:Eu3+荧光粉十分接近的接近纯色的红色荧光粉。Ca10K(PO4)7:Eu3+是一种可望应用于紫外激发的白光LED的红色荧光粉。     

La~(3+)掺杂对BaSi_2O_2N_2∶Eu~(2+)荧光粉发光性能的影响

研究了La3+掺杂对BaSi2O2N2∶Eu2+发光性能的影响。通过高温固相反应制备了纯相的Ba0.94-Si2O2N2∶0.06Eu2+荧光粉。在此基础上进行La3+的掺杂,并对少量La3+掺杂的LaxBa0.94-1.5xSi2O2N2∶0.06Eu2+荧光粉的结构和光学性能进行了研究。XRD图谱表明粉体在低掺杂时保持了基质BaSi2O2N2的晶格结构。通过共掺x=0.035的La3+可使荧光粉的发光效率提高到157%,原因是La3+部分取代Ba2+产生了阳离子缺陷,其可以吸收光源能量并将能量传递给Eu2+。最终这些能量通过Eu2+的4f65d→4f7跃迁以光辐射的形式释放出来。     

(Mg1-xSrx)2Al4Si5O18陶瓷的显微结构与微波介电性能研究

采用固相烧结反应法制备(Mg1-xSrx)2Al4Si5O18陶瓷.Sr掺杂促进低温相β-Mg2Al4Si5O18向高温相α-Mg2Al4Si5O18转变,并拓宽了(Mg1-xSrx)2Al4Si5O18陶瓷的致密化烧结温度范围.X射线衍射结果表明在0≤x<0.2范围内,(Mg1-xSrx)2Al4Si5O18陶瓷以(Mg,Sr)2Al4Si5O18堇青石固溶体形式存在;在0.6相似文献   

Characterization and luminescence of Eu3+ ions doped 12CaO 7Al2O3 nanopowders

Eu3+ ions doped 12CaO 7Al2O3 (C12A7) powders with different Eu3+ concentrations were prepared by sol-gel combined with solid state reaction method. The results of XRD and Raman spectra showed that single cubic phase polycrystalline C12A7:Eu3+ powders were prepared. The absorption peaks attributed to f-f transition of Eu3+ ion can be observed, indicating that Eu3+ had been incorporated into C12A7 lattice site. Visible PL peaks around 578, 588, 614 nm were ascribed to 5D0 --> 7FJ (J = 0, 1, 2) transitions of Eu3+ under the excitation of 488 nm line. The PL of C12A7:Eu3+ showed the strongest emission intensity at Eu3+ concentration of 0.5 at%. Two different types of Eu3+ centers were identified by the two lines from 5D0 --> 7F0 transition emission. The doping mechanism of C12A7:Eu3+ might be attributed to Eu3+ ions substitution for two types of Ca2+ lattice sites in C12A7. The temperature dependent PL spectra of Eu-doped C12A7 were measured in the range from 100 to 300 K under the excitation of 488 nm laser line. The PL intensities as a function of temperature were well fitted by using a unified theoretical model, considering thermal activation and nonradiative energy transfer processes.     

Eu3+对Na3Gd2(BO3)3∶Tb3+发光性能的影响及其能量传递

采用高温固相法制备了Na_3Gd_2(BO_3)_3∶Tb~(3+),Eu~(3+)荧光粉,并对样品的物相组成、微观形貌、发光性能和能量传递进行了分析。结果表明,Na_3Gd_(2-x)(BO_3)_3∶xTb~(3+)荧光粉在紫外和近紫外区域有较强的激发峰,在368nm波长激发下,发射光呈绿色,Tb~(3+)最佳掺杂量为x=0.04。随着在Na_3Gd_(1.96)(BO_3)_3∶0.04Tb~(3+)中掺入Eu~(3+),Tb~(3+)对Eu~(3+)产生了以电偶极-电偶极相互作用为主的能量传递,且传递效率随Eu~(3+)掺杂量的增加而逐渐增大。发射光谱中Tb~(3+)的发射峰强度逐渐减弱,而Eu~(3+)的发射峰强度逐渐增强,导致Na_3Gd_(1.96-y)(BO_3)_3∶0.04Tb~(3+),yEu~(3+)荧光粉发光颜色由绿色向橙色变化。     

稀土掺杂双钙钛矿结构红色荧光粉的制备及其发光性能

采用高温固相反应法制备了Sr_(2-x)BaxMgMoO_6∶Eu~(3+)(x=0~1)双钙钛矿结构红色荧光粉。探讨了预处理及煅烧制度、Ba取代量对Sr_(2-x)BaxMgMoO_6∶Eu~(3+)荧光粉的相结构和发光性能的影响。Sr_2Mg_(0.94)Eu_(0.06)MoO_6荧光粉最佳制备工艺为:在700℃下预处理1h再升温至1050℃预处理1h并随炉降温后研细,再在1300℃煅烧4h,所得样品主相为双钙钛矿结构的Sr2MgMoO6四方相。其最强发光峰位于617nm附近,对应于Eu3+的5D0→7F2电偶极跃迁。随着Ba2+对Sr2+的取代量的增加晶体对称性提高,晶体结构由四方相变为立方相,样品的激发峰强度显著提高。由于晶体对称性的提高,抑制了荧光粉在617nm处5D0→7F2红光发射,其发光由电偶极跃迁占主导转变为磁偶极跃迁占主导。     

Dielectric and Piezoelectric Properties of (Na0.5Bi0.5)(Ti1–xMnx)O3 (x = 0–0.1) Modified Ceramics

Inorganic Materials - We have studied the crystal structure and dielectric and local piezoelectric properties of (Na0.5Bi0.5)(Ti1–xMnx)O3 (x = 0–0.1) modified sodium bismuth...