掺锶量对羟基磷灰石形貌及其荧光特性的影响

采用水热合成法制备了一系列具有不同微观形貌和荧光性能的掺锶羟基磷灰石粉末。通过X射线衍射、红外光谱、电子能谱、扫描电镜和荧光光谱表征样品的物相、形貌及荧光性能。结果表明: 所制备的样品形貌为1~ 3 μm的由微小晶粒聚集而成的球形颗粒, 但随着掺锶量的变化, 组成球形颗粒的微小晶粒形貌会出现较大的差异。 未掺锶羟基磷灰石晶粒形貌为短棒状, 随着掺锶量的增加, 微小晶粒逐渐变为片状而后转变为长棒状。样品能在紫外光(波长351 nm)激发下发出明亮的蓝色荧光(波长375~500 nm, 最强峰位432 nm), 且荧光强度随掺锶量增加先增强, 而后减弱, 在掺锶量为30mol%时达到最大。     

Luminescence of Unusual Bismuth in Barium Borates (BaB8O13:Bi)

Theuniqueorange-redluminescenceofunusualdi-valentbismuthinstrolltiumtetraborate(SrB'O,)[']andalkalineearthborophosphates[2]havereportedrecently.Thestabilizationofthedivalentokidationstateofbismuthinthesehostsisattributedtotheuniquemolecularstructure.Thecationsaretetrahe-drallycoordinatedbyBo4unitsinthehostlattices.Thebismuthisenclosedbythethree-dimensionalBO`networkandhardlyexpectedtobeattackedbyoxygenintheairathightemperatureandhencethedivalentstateofBi2+ionwillbecomeverysta-ble.Sincebariu…     

锶含量对稀土Eu掺杂锶钙羟基磷灰石发光性能及取代位置的影响

采用化学共沉淀法制备了一系列Sr含量不同的铕掺杂锶钙羟基磷灰石粉体(Ca_10-x-Sr_x-HAp: Eu), 通过X射线衍射(XRD)、荧光光谱以及发光能量传递等研究了锶含量对稀土掺杂锶钙羟基磷灰石结构、荧光性能和取代位置的影响。XRD分析表明, 掺杂Eu对锶钙羟基磷灰石样品的结构无明显影响, 而Sr含量增加会使得样品的结晶程度和晶面间距增大。光谱分析表明, 在394 nm波长激发下, Ca_10-x-Sr_x-HAp: Eu样品在596 nm和618 nm处的荧光强度随着Sr含量的增加先升高再降低, 最强峰值出现在Ca₃-Sr₇-HAp: Eu样品中。同时, 样品的荧光寿命随着Sr含量增加也出现相同的变化。此外, 随着基体中Sr含量的增加, 样品的电偶极跃迁与磁偶极跃迁强度比值(I_R/I_O)先增加后减小, 而Eu荧光衰减过程中不同格点之间的能量传递参数(f)则先减小后增大, 两者的转折点都出现在Ca₃-Sr₇-HAp: Eu样品中。实验表明: Eu在基质晶格中的取代位置受Sr在基质中含量和位置的影响, 通过Sr/Ca比例的调节则可以使得Eu在基质中取代不同位点的比例变化进而获得可调节的荧光性能。     

硼酸对蓝色铝酸锶长余辉材料的物相及发光特性的影响

采用高温固相法制备了xSrO·yAl2O3:Eu2+,Dy3++m%(摩尔分数)(H3BO3)(m=15,20,23,25,30,35)系列蓝色光致发光材料。X射线衍射(XRD)结果表明:m=15～20之间产品为SrAl2O4,Sr2Al6O11和Sr4Al14O25的混合物,m=23时产品主相为Sr2Al6O11,m=25～35之间产品主相为Sr4Al14O25。利用荧光分光光度计和亮度计研究了材料的发射光谱,衰减曲线,结果显示:随着硼酸量的增加,发射峰值先蓝移后红移,而余辉时间则逐渐变长。从而得到了制备蓝色铝酸锶发光材料Sr2Al6O11:Eu2+,Dy3+的最佳硼酸量,并且对硼酸在材料合成过程中的作用机理进行了探讨。     

硼酸盐晶体的结构特征与新材料设计

从硼酸盐晶体的结构出发,综述了硼酸盐的不同分类方法,并在此基础上详细介绍了复杂晶体化学键理论及其在硼酸盐晶体非线性光学性质上的应用.此外,介绍了键合模型及其对硼酸盐晶体结构的预测,提出了从硼酸盐的结构预测到结构分类再到非线性光学效应计算的一体化的硼酸盐晶体材料设计的新思路.     

Preparation and Characterization of Copper Borates as Lubricant Additives

The present study attempts the preparation of copper borate as a lubricating oil additive by the reaction of copper nitrate and borax solutions. Effects of borax/copper ratio, surface active agent （Span 60）, pH, temperature and mixing time on properties of the products were investigated. The obtained products were not pure form; therefore they were analyzed in detail. They were characterized by color measurement, X-ray diffraction, SEM, zeta sizer, ICP, EDX, TG, DSC, CHNS analysis and FTIR spectroscopy. Mainly Cu2（OH）3NO3 with nitrate ions partially substituted with borate ions was obtained at pH 3.7. There were borate ions equivalent to 0.32 tools of Cu（BO）2 per tool of CUE（OH）3NO3. The borate ions should have replaced partially the nitrate ions in Cu2（OH）3NO3 without changing its crystal structure. On the other hand, Cu （BO2）l 5（OH）074＇（H20）015 was produced at pH 10.2. It also contained 0.11 mol NO3- per tool. By mixing of dilute solutions at pH 8.2 and drying at room temperature nanopartieles of Cu（BO2）I 5（H20）6 having 0.05 NO3 per tool was obtained. The precipitates obtained at pH 10.1 and 8.2 were tested as lubricant additives. When they were added to lubricating oil with Span 60, the friction coefficient was reduced 28 % and 65 % for the precipitates prepared at pH 10.1 and 8.2, respectively.     

Homogeneity Range of Samarium Manganite in Air

The solubility limits of samarium and manganese oxides in SmMnO₃ are determined using x-ray diffraction analysis of Sm_{2 ? x}MnxO₃ samples (0.90 ≤ x ≤ 1.20, Δx = 0.02) prepared from oxide mixtures by solid-state reactions in air between 800 and 1400°C. The composition dependences of lattice parameters are presented for samarium manganite synthesized at 1400°C. The solubility of samarium oxide in SmMnO₃ is tentatively attributed to structural defects, and that of manganese oxides is interpreted in terms of structural defects, oxygen nonstoichiometry of samarium manganite, the disproportionation reaction 2Mn³⁺ =Mn²⁺ + Mn⁴⁺, and partial substitution of the resulting Mn₂₊ for Sm₃₊ on the cuboctahedral site of the perovskite structure.     

火焰原子吸收光谱法测定光学新材料钛酸钡锶中钡和锶

本文介绍了火焰原子吸收光谱法测定光学新材料钛酸钡锶中钡和锶,研究样品制备、测试条件和共存元素干扰消除。本法的准确度和精密度均达到满意的结果。     

Double Cyclohexaphosphates of Cesium and Divalent Metals

The double cyclohexaphosphates Cs₂Mg₂P₆O₁₈ (forms I and II) and Cs₂Zn₂P₆O₁₈ (II) are prepared by reacting Cs₂CO₃ and MgO or ZnO in molten polyphosphoric acids in the presence of Ln₂O₃ (Ln = Lu, Yb) or V₂O₅ at 250–350°C. Their structures and lattice parameters are determined. Cs₂Mg₂P₆O₁₈-I: a = 18.243 Å, b = 12.023 Å, c= 12.021 Å, = 96.86°, sp. gr. Pc; Cs₂Mg₂P₆O₁₈-II:a= 12.042 Å, sp. gr. P2₁3; Cs₂Zn₂P₆O₁₈: a= 12.023 Å, sp. gr. P2₁3. Yb and Lu do not form mixed-cation phosphates with Cs, Mg, or Zn but are favorable for cyclization and the formation of the double cyclohexaphosphates Cs₂Mg₂P₆O₁₈ and Cs₂Zn₂P₆O₁₈.     

Heat Capacity and Thermal Expansion of Samarium Hafnate

Inorganic Materials - The molar heat capacity and lattice parameter of samarium hafnate with the pyrochlore structure have been measured as functions of temperature in the ranges 320–1300 and...     

Eu~(2+)掺杂硫化锶/铝酸锶复合体系的发光性能

采用高温固相法制备了Eu2+掺杂的硫化锶/铝酸锶复合荧光体样品,研究了样品随组成成分变化的相变过程及其光谱特性。结果表明,随着n(SrSO4)/n(SrCO3+SrSO4)值的增加,样品中铝酸锶成分逐步由SrAl2O4相向SrAl4O7相转变。在469nm激发下,当SrSO4达到8%(摩尔分数)时红光发射强度最强。此外,该复合荧光体能在417nm激发下得到红绿双波段荧光,且红、绿荧光相对强度可通过变化基质成分实现调节,在近紫外LED照明上具有潜在的应用价值。更重要的是,该复合荧光体中的SrS成分在铝酸盐的包覆下耐水性得到显著改善,有效增强了其实用性。     

钛酸锶的还原工艺和晶粒性质

将纯钛酸锶陶瓷和石墨粉放入加盖坩埚内加热，可使晶粒电阻率降低至９．２３Ωｃｍ；而晶界呈电容性，其电阻比晶粒大五十倍。在氢气氛中将钛酸锶陶瓷还原，则晶界近于短路。用极化子跳跃导电对晶粒的电感性作了解释。     

锶在镁合金中的应用及其研究新进展

综述了锶对镁合金组织和性能的影响以及Mg-Al-Sr耐热镁合金开发的研究概况,分析了锶对镁合金组织的细化和变质机理.研究表明,锶是对镁合金组织和性能有益的合金元素,主要体现在细化和变质合金的组织、减少铸造缺陷的产生、提高合金高温下的机械性能.此外,指出了目前还存在的问题,并对今后的发展进行了展望.     

Valence stability of molybdenum in alkaline earth molybdates

Presence of oxygen stability range in ternary oxides was experimentally verified for molybdenum(IV) perovskites, and the widths of stability range were determined of BaMoO₃, SrMoO₃ and CaMoO₃. Moreover, the tetravalent state of molybdenum was found to be more strongly stabilized in these compounds than in its binary oxide. A concept of lattice self-potential was examined in order to explain this phenomenon. Contribution of A-cation to the retention of high valence state of B-cation in the perovskite ABO₃ was also discussed.     

含钐稀土-高分子荧光材料的制备和表征

合成了聚N-异丙基丙烯酰胺-丙烯酸P(NIPAM-co-AAc)共聚微凝胶与Sm(Ⅲ)离子、α--噻吩甲酰三氟丙酮(HTTA)的三元配合物.用激光光散射、Zeta电位、紫外光谱、红外光谱、荧光光谱进行了表征.结果表明,微凝胶粒径为360nm;Sm(Ⅲ)与微凝胶、HTTA之间以配位作用为主;微凝胶、HTTA和Sm(Ⅲ)之间能进行有效的能量传递.配合物的最佳激发波长为348 nm,在此激发波长下Sm(Ⅲ)有荧光特征发射.     

原子吸收光谱法测定光学新材料钛酸钡锶中锶的研究

本文介绍火焰原子吸收光谱法测定光学新材料钛酸钡锶中锶的方法,研究样品制备和测试条件,消除共存元素干扰。本法的回收率为99～101％,相对标准偏差为0.72％。     

Mixture of Oxides with Different Valence States in Nanotubes

Oxide nanotubes with different diameters and lengths were fabricated on the biomedical Ti2448 alloy by anodic oxidation in neutral electrolyte.Similar to oxide nanotubes fabricated on pure titanium and its alloys,the as-grown nanotubes on Ti2448 also exhibit gradually changing chemical distribution along the direction of tube growth.Furthermore,several kinds of oxides with different valence states(MxOy)are formed simultaneously for each alloying element M,while their volume fractions vary gradually along the tube-growth direction.The findings of this study would provide insight into the effect of valence states on the desired nanotube properties and help develop ways to enhance the properties of the preferred oxide.