稀土含氮黄长石固溶体R2Si3-xAlxO3+xN4-x的X射线衍射研究

用热压和无压烧结工艺，在１７００～１８００℃制备了含氮稀土黄长石固溶体Ｒ２Ｓｉ３－ｘＡｌｘＯ３＋ｘＮ４－ｘ（Ｒ＝Ｎｄ，Ｓｍ，ｘ＝０，０．３，０．６，１．０，１．２；Ｒ＝Ｄｙ，Ｙ，Ｘ＝０，０．３，０．６，１．０；Ｒ＝Ｙｂ，Ｘ＝０，０．３）利用Ｇｕｉｎｉｅｒ－Ｈａｅｇｇ照相法，光密度计在ＬＳ－１８和相应的程序系统（ＳＣＡＮ，ＳＣＡＮＰＩ和ＰＩＲＵＭ）给出了稀土黄长石的Ｘ射线衍射图谱，精密测定了具有不同     

用于燃料电池的Ln_（1－x）Sr_xMnO_3系阴极材料的研究

用固相反应合成了Ｌｎ１－ｘＳｒｘＭｎＯ３（Ｌｎ＝Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ，Ｙｂ和Ｙ，ｘ≤０．５）系钙钛矿型多元氧化物，用Ｘ光衍射分析测定了反应产物的相组成和结构类型．离子半径＞０．１Ａ的Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ等取代后的Ｌｎ１－ｒＳｒｘＭｎＯ３仍具有正交ＬａＭｎＯ３的结构，而离子半径＜０．９５Ａ的Ｙ和Ｙｂ取代后的产物，则为六方结构（Ｙｂ，Ｙ）ＭｎＯ３及第二相Ｓｒ（Ｙｂ，Ｙ）２Ｏ４还测定了产物的烧结性能和电导率．发现（Ｐｒ，Ｎｄ，Ｓｍ）１－ｘＳｒｘＭｎＯ３的电导率比Ｌａ１－ｘＳｒｘＭｎＯ３约高一个数量级以上，而且都能在ＺｒＯ２固体电解质上形成结合良好的膜材，所以有可能成为另一类性能良好的燃料电池的阴极材料．     

无Co混合导电型陶瓷透氧膜的制备和性质研究

首次合成了Ｓｒ１０－ｎ／２ＢｉｎＦｅ２０Ｏｍ（ｎ＝２，４，６，８，１０等）系列氧化物透氧膜，它们具有较高的透氧能力，其中，样品ｎ＝１０在１１００Ｋ时的透氧率为０．９０ｍｌ（ＳＴＤ）／（ｃｍ２·ｍｉｎ），比Ｓｒ１－ｘＢｉｘＦｅＯ３高约两倍．Ｓｒ１－ｘＢｉｘＦｅＯ３（ｘ＝０．１，０．３，０．５）系列的透氧率随Ｂｉ含量增加而增大．通过两个系列氧化物的ＸＲＤ和化学组成的对比，发现Ｂｉ离子含量和晶格空位浓度对透氧能力大小起决定性作用．     

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。     

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     

P2O3—B2O3—Al2O3—SrO—BaO玻璃中的Yb^3＋非辐射能量转移下E …

本文研究了共掺Ｅｒ＾３＋／Ｙｂ＾３Ｐ２Ｏ３－Ｂ２Ｏ３－Ａｌ２Ｏ３－ＳｒＯ－ＢａＯ玻璃的能量转移过程。实验中制备了高掺杂Ｂｂ＾３＋离子的双掺Ｅｒ＾＃＋／Ｙｂ＆＾３＋的磷酸盐玻璃样品。在Ｅｒ＾３＋／Ｙｂ＾３＋掺杂比率〉１：１８（ｍｏｌ％）时,观测到了基于Ｙｂ＾３＋离子至Ｅｒ＾３＋离子能量转移下Ｅｒ＾３＋（＾３Ｉ１３／２→＾４Ｉ１５／２）的增强发射和ｂ＾３＋（＾２Ｆ７１／→＾２Ｆ５／２）发射的减弱,当Ｂ     

用于燃料电池的Ln1—xSrxMnO3系阴极材料的研究

用固相反应合成了Ｌｎ１－ｘＳｒｘＭｎＯ３系钙钛矿型多元氧化物，用Ｘ光衍射分析测定了反应产物 相组成和结构类型。离子半径〉０．１Ａ的Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ等取代后的Ｌｎ１－ｘＳｒｘＭｎＯ３仍具有正交ＬａＭｎＯ３的结构，而离子半径〈０．９５Ａ的Ｙ和Ｙｂ取代后的产物，则为六方结构（Ｙｂ，Ｙ）ＭｎＯ３及第二相Ｓｒ（Ｙｂ，Ｙ）２Ｏ４。还测定了产物的烧结性能的电导率。发现（Ｐｒ，Ｎｄ，Ｓｍ）１－ｘＳｒｘＭｎＯ     

MSnO3和MSn0.5Zr0.5O3（M=Sr,Ba）的水热合成

本文利用水热合成方法对ＭＳｎＯ３和ＭＳｎ０．５Ｚｒ０．５（Ｍ＝Ｓｒ，Ｂａ）的合成进行了研究，并采用ＸＲＤ、ＳＥ几ＩＣＰ等进行产物进行了表征，结果表明：在Ｍ（ＯＨ）２．ＳｎＯ２（呈ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ体系中，当ＫＯＨ／Ｓｎ和ＫＯＨ（Ｓｎ＋Ｚｒ）≥３０时，２６０℃下晶化５－７天，可获得ＭＳｎＯ３和ＭＳｎ０．５Ｏ３纯相，在Ｍ（ＯＨ）３－（ＳｎＯ２＋ＺｒＯ３）－ＫＯＨ－Ｈ２Ｏ体系中，可通过控制介质     

MSnO_3和MSn_（0．5）Zr_（0．5）O_3（M＝Sr，Ba）的水热合

本文利用水热合成方法对ＭＳｎＯ３和ＭＳｎ（０．５）Ｚｒ（０．５）Ｏ３（Ｍ＝Ｓｒ，Ｂａ）的合成进行了研究，并采用ＸＲＤ、ＳＥＭ和ＩＣＰ等方法对产物进行了表征，结果表明：在Ｍ（ＯＨ）２－ＳｎＯ２（或ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ体系中，当ＫＯＨ／Ｓｎ和ＫＯＨ／（Ｓｎ＋Ｚｒ）≥３０时，２６０℃下晶化５～７天，可获得ＭＳｎＯ３和ＭＳｎ（０．５）Ｚｒ（０．５）Ｏ３纯相，在Ｍ（ＯＨ）２－（ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ－Ｈ２Ｏ体系中，可通过控制介质碱度来获得ＭＳｎＯ３＋ＭＺｒＯ３混合物和ＭＳｎ（０．５）Ｚｒ（０．５）Ｏ３，并根据合成规律初步探讨了反应过程．     

Bi2（Te1—xSex）3单晶生长热力学研究

本工作研究了Ｂｉ－Ｆｅ－Ｓｅ三元相在富Ｂｉ２Ｔｅ３区的相图。测定了Ｂｉ２Ｔｅ３和Ｂｉ２Ｓｅ３从５５０℃到它们的熔点范围内的等浓度线,用移动加热器（ＴＨＭ）法生长Ｂｉ２（Ｔｅ１－ｘＳｅｘ）３（ｘ＝０．０２５和ｘ＝０．０５）。用霍尔（Ｈａｌｌ）效应测定这些化合物在富Ｔｅ区的固线,研究表明,可再生法生长热力学定义的单晶是可能的。     

Optically and thermally stimulated luminescence of KMgF3:Ce3 and NaMgF3:Ce3+

The potentialities of optically stimulated luminescence (OSL) for personal dosimetry of ionising radiation have stimulated the search for new synthetic materials with good dosimetric properties. The sensitivity of two new OSL materials KMgF3 and NaMgF3 doped with Ce3+ ions has been evaluated and found to be of the same order of magnitude as that of Al2O3:C. Several other characteristics have also been investigated. Promising results for KMgF3:Ce are the high sensitivity and the low fading. However, this material suffers from a high self-dose due to the presence of 40K. NaMgF5:Ce is sensitive as well but shows strong fading. Interesting information on the mechanism has been obtained by correlating the signals of OSL and TL. Furthermore, the different bleachabilities under blue LED illumination of the strongly overlapping glow peaks allowed the extraction of one single peak for KMgF3:Ce3+. The results demonstrate new possibilities offered by the combination of TL and OSL.     

LiTaO3 and LiNbO3 Epitaxial Films

The preparation of film-forming peroxide solutions of LiTaO₃ and LiNbO₃ precursors is described. The solutions are used to produce LiTaO₃ films on single-crystal corundum and LiNbO₃ substrates by the spinning process and dip coating, followed by heat treatment, and LiNbO₃ films on single-crystal corundum substrates by the spinning process.     

Heat capacities and latent heats of LiNO3, NaNO3, and KNO3

Enthalpies of fusion and transition together with heat capacities in both solid and liquid phases have been measured on LiNO₃, NaNO₃, and KNO₃ with a high accuracy by differential scanning calorimetry (DSC). Polynomial expressions of heat capacities are given.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

Dielectric Relaxation and Conductivity of Ba(Mg1/3Ta2/3)O3and Ba(Zn1/3Ta2/3)O3

The frequency dependent dielectric properties of barium magnesium tantalate(BMT),Ba(Mg_(1/3)Ta(2/3))O_3 and barium zinc tantalate(BZT),Ba(Zn_(1/3)Ta_(2/3))O_3 synthesized by solid state reaction technique have been investigated at various temperatures by impedance spectroscopy.BMT and BZT possess cubic structure with lattice parameter a = 0.708 and 0.451 nm,respectively.The resonance peaks due to dielectric relaxation processes are observed in the loss tangent of these oxides.The relaxation in the samples is polydispersive in nature.The temperature dependence of dc conductivity,the most probable relaxation frequency(ω_m) obtained from tanδ vs logw plots and ω_m obtained from imaginary parts of the complex electrical modulus vs logw plots follow the Arrhenius behavior.According to these Arrhenius plots the activation energies of BMT and BZT are about 0.54 and 0.40 eV,respectively.Thus the results indicate that samples are semiconducting in nature.The frequency-dependent electrical data are analyzed in the framework of conductivity and electric modulus formalisms.Both these formalisms show qualitative similarities in relaxation time.Our study points that for complex perovskite oxides with general formula A(B'B")O_3,the dielectric properties significantly depend on the atomic radii of both A and B type cations.BMT and BZT exhibit enhancement in dielectric property compared to their niobate counterparts.They may find several technological applications such as in capacitors,resonators and filters owing to their high dielectric constant and low loss tangent.     

溶液法CH3NH3PbCl3单晶的生长与性能研究

分别采用蒸发结晶法和逆温结晶法生长尺寸约为4 mm×3 mm×3 mm的CH₃NH₃PbCl₃单晶。对两种方法生长的单晶粉体的XRD分析结果显示, 单晶具有立方晶系结构, 其晶格常数分别为0.56833、0.56891 nm。实验测量了CH₃NH₃PbCl₃单晶的红外光谱(FT-IR)和拉曼光谱, 并对谱峰进行了指认; 使用UV-VIS-NIR分光光度计、荧光光度计对CH₃NH₃PbCl₃单晶的光学性能进行了测试。结果表明: CH₃NH₃PbCl₃晶体的吸收边约为423 nm, 光致发光峰为433 nm, 带隙值为2.97 eV, 与CH₃NH₃PbCl₃薄膜的光学特性相比, CH₃NH₃PbCl₃单晶更具潜在的应用前景。最后, 结合第一性原理研究了CH₃NH₃PbCl₃晶体的能带结构, 计算得出带隙值2.428 eV, 与实验值吻合较好。