Intercalation of pyrographite by NO2+ and NO+ salts

BF₄^?, PF₆^? and SbF₆^? ions have been intercalated into pyrographite HOPG by chemical oxidation. The graphite is oxidized by NO₂⁺ (or NO⁺ in certain experiments) coming from NO₂BF₄, NO₂PF₆ and NO₂SbF₆ (or NOSbF₆) salts dissolved in dry nitromethane. X-ray diffraction allows us to determine the identity period along the $\text{c}$ axis leading to the stage n and the interpianar distance d_I. Relative weight change leads us to believe that the MF_x^? anions are solvated by the solvent. Chemical analyses confirm this hypothesis allowing us to give to these compounds the ideal formula C⁺_23nMF^?_x (CH₃NO₂)_y.     

Luminescent branching ratios and radiative lifetimes of Tm3+ in POCl3:SnCl4 laser liquid

For the first time, the optical spectrum of Tm³⁺ ion in POCl₃:SnCl₄ laser liquid was recorded in the UV-VIS and NIR regions. From the observed energy levels, Racah (E^h), spin-orbit (ξ_4f) and configuration interaction (α, β) parameters we evaluated by the least-squares fit method. Radiative transition probabilities and luminescent branching ratios were calculated for the excited fluorescent levels of Tm³⁺ ion using the Judd-Ofelt theory and the intensity parameters obtained from the measured intensities of the absorption bands.     

The luminescence of Eu3+, Tb3+ and Tm3+ activated Gd2BaZnO5 and La2BaZnO5

The luminescence of several rare-earth activators in the new compounds Gd₂BaZnO₅ and La₂BaZnO₅ is reported and discussed. Activation with the Eu³⁺ ion yields highly efficient red-emitting phosphors. Some unknown structural details can be derived from the luminescence spectra.     

Luminescent properties of GdAl3(BO3)4:Ln3+ (Ln3+:Eu3+, Tb3+, Dy3+) nano-phosphors

GdAl₃(BO₃)₄:Ln³⁺ (Ln³⁺:Eu³⁺, Tb³⁺, Dy³⁺) nano-phosphors were prepared by sol–gel method. The structure properties of the phosphors are characterized by XRD, and GdAl₃(BO₃)₄:Ln³⁺ nano-phosphors have average sizes around 40 nm. The doping concentrations of Eu³⁺, Tb³⁺ and Dy³⁺ ions in GdAl₃(BO₃)₄ nano-phosphors are from 1 to 9 mol% for Eu³⁺ ions, from 2 to 12 mol% for Tb³⁺ ions and from 1 to 5 mol% for Dy³⁺ ions, respectively. The luminescent properties of rare-earth ions doped GdAl₃(BO₃)₄ nano-phosphors are analyzed by the photoluminescence spectra, which prime doping concentration of Eu³⁺, Tb³⁺, and Dy³⁺ ions are at 5, 12 and 3 mol%, respectively. The energy transfers in the luminescent processes of rare-earth ions doped GdAl₃(BO₃)₄ nano-phosphors are discussed.     

Analysis of oxyanion (BO33?, CO32?, SO42?, PO43?, SeO44-) substitution in Y123 compounds studied by X-ray photoelectron spectroscopy

XPS core level spectra of Y123 compounds doped by C, B, S, P, and Se elements are presented. It is found that the C1s, E1s, S2p, P2p, and Se3d binding energies of doped compounds are close to those of CaCO₃, FeBO₃, CuSO₄, NaH₂,PO₄, and SeO₂, reference compounds. It is concluded that these impurity elements form oxyanion groups in Y123 compounds.     

Sm3+/Ce3+/Tb3+共掺CaO-B2O3-SiO2发光玻璃的制备及发光性能研究

采用高温熔融法制备了Sm3+/Ce3+/Tb3+共掺杂的CaO-B2O3-SiO2发光玻璃材料,并用荧光分光光度计和CIE色度坐标对其发光性能进行了研究。发射光谱表明,在374nm激发下,Sm3+/Ce3+/Tb3+共掺杂CaO-B2O3-SiO2发光玻璃的发射光谱中同时观测到了红橙光、蓝光和绿光的发射带,这些发射带的混合实现了白光发射。此外,在Sm2O3和Tb4O7含量不变的情况下,随着CeO2含量的减小,Sm3+/Ce3+/Tb3+共掺杂发光玻璃的发光颜色在白光区逐渐由蓝光区附近过渡到黄光区附近。     

白光LED用Sr3-x-yMySiO5:Eux2+系列发光材料性能的研究

采用高温固相法合成白光LED用Sr3-x-yMySiO5:Eu2x+(M=mg2+、Ca2+、Ba2+、Zn2+等)发光材料,优化荧光粉的合成条件,测定样品的光谱数据,寻找Eu2+和Mg2+、Ca2+、Ba2+、Zn2+等的最佳掺杂量,使其在460nm蓝光激发下得到最优的光谱性能。     

CeO2∶Eu3+纳米晶的发光特性与Gd3+离子掺杂影响研究

以尿素为燃烧剂,采用低温燃烧法制备了Eu3+单掺杂和Eu3+、Gd3+共掺杂CeO2纳米晶粉末,用X射线衍射(XRD)和透射电镜(TEM)对样品进行了结构分析和形貌表征.对掺杂Gd3+离子的CeO2∶1％ Eu3+纳米晶的光谱研究发现,随着Gd3+离子掺杂浓度的增加,5D0→7F2跃迁与5D0→7F1跃迁的强度比随之增加,这表明Eu3++离子的格位对称性有所下降,且有利于提高红橙光的比例.鉴于CeO2基质在300～390nm有强吸收,Eu3+掺杂CeQ2纳米晶在近紫外激发LED荧光粉方面有潜在应用前景.     

Er3+/Yb3+掺杂NaGd(WO4)2粉体的制备与发光性能

采用水热法成功制备了Er~(3+)/Yb~(3+)双掺杂的NaGd(WO_4)_2纳米粉体,研究了不同络合剂、水热温度对样品形貌和结构的影响。测量了不同Er~(3+)掺杂浓度样品的可见上转换和近红外发射光谱。结果表明:在980nm LD激发下,可观测到样品强烈的绿色上转换发光,对应Er~(3+)的~2H_(11/2)→~4I_(15/2)(530nm)和~4S_(3/2)→~4I_(15/2)(552nm)跃迁,以及较弱的红色上转换和近红外发光,分别对应Er~(3+)的~4F_(9/2)→4I15/2(656nm)和~4I_(13/2)→~4I_(15/2)(1 532nm)跃迁。且随着Er~(3+)掺杂浓度的增加,样品的上转换红绿光和1.54μm附近的近红外光均呈现出先增大后减小的趋势。样品的激发和发射光谱显示,在378nm处的激发峰最强,对应Er~(3+)的~4I_(15/2)→~4 G_(11/2)能级跃迁,最强发射峰位于552nm。根据泵浦功率与发光强度的关系可以得出,红光和绿光的发射主要为双光子吸收过程,但红光还包含了一定的单光子吸收成分。     

Synthesis and study of compounds A 2I (UO2)2Si5O13 · 3H2O (AI = Na, K)

Sodium and potassium diuranyl pentasilicates were prepared by precipitation from a solution followed by hydrothermal treatment. The structure, properties, and thermal behavior of these compounds were studied by X-ray diffraction, IR spectroscopy, and thermal analysis. Original Russian Text ? N.G. Chernorukov, A.V. Knyazev, A.A. Sazonov, 2007, published in Radiokhimiya, 2007, Vol. 49, No. 2, pp. 114–115.     

Physical prerequisites, mechanisms, and kinetics of formation of Pd 2+ molecular complexes in metallic palladium

The issue of whether Pd₂⁺ molecular complexes can be formed in metallic palladium has been considered. It has been shown that in the structure of the face-centered cubic palladium crystal lattice, there are the energy and geometric prerequisites for the formation, from the atoms at the centers of adjacent lattice faces, of Pd₂⁺ molecular complexes with a hole in the 4d shell of one atom. The average content of these complexes and holes per palladium atom has been evaluated. Possible mechanism and kinetics of formation of Pd₂⁺ molecular complexes in metallic palladium have been considered.     

硼酸铋玻璃中Er3+和Yb3+的光谱特性

采用熔体冷却法制备了单掺Er3+和Yb3+的硼酸铋玻璃,并利用理论方法计算了硼酸铋玻璃中Er3+和Yb3+的光谱参数.详细分析了硼酸铋玻璃中Er3+和Yb3+离子光谱参数与玻璃组成和掺杂浓度的关系,并研究了Yb3+离子的辐射陷阱效应.实验表明,掺Er3+和Yb3+的硼酸铋玻璃是一种具有潜在发展前途的固体激光器和光纤放大器用激光材料.     

Luminescence properties for the high-pressure polymorphs of CaSiO3:Pb2+ and SrSiO3:Pb2+

High-pressure phases of CaSiO₃:Pb²⁺ and SrSiO₃:Pb²⁺ phosphors were synthesized at 40–55 kbar and 1000°C, $\text{viz}$. δ-CaSiO₃:Pb²⁺, δ-SrSiO₃:Pb²⁺, and δ′-SrSiO₃:Pb²⁺, and their luminescence properties were investigated. Among them, δ-CaSiO₃:Pb²⁺ was found to give a strong violet-blue emission ($\text{ca}$. 341 nm) as well as β-CaSiO₃:Pb²⁺ (an atmospheric phase), and the emission intensity of SrSiO₃:Pb²⁺ drastically increased when the host lattice transformed into high-pressure phases (δ and δ′ forms). These results were discussed by considering their structures and quenching temperatures of luminescences.     

铅离子显色印迹吸附剂的制备及其吸附性能

以Pb2+为模版分子,在硅胶表面接枝双硫腙,利用溶胶-凝胶法合成一种Pb2+显色印迹吸附剂(MIPs)。采用红外(IR)和扫描电镜(SEM)对MIPs进行了表征。通过平衡吸附实验,研究了MIPs的吸附性能、显色性能和其对Pb2+的选择识别性能。结果表明,双硫腙通过与硅胶形成氢键而接枝在硅胶表面;MIPs对Pb2+的显色限为10μmol/L;在Cd2+存在的条件下,其对Pb2+的相对选择系数为250;MIPs对Pb2+的吸附可以用Langmiur等温吸附方程来拟合,吸附焓变为66.054kJ/mol。制备的MIPs在5min内吸附率可以达到97%,可以用于含铅废水中Pb2+的分离和测定。     

Effects of pH and initial Ca2+?H2PO4? concentration on fibroin mineralization

In the present study, the effects of pH and initial Ca²⁺−H₂PO₄ ⁻ (Ca-P) concentration on fibroin mineralization were studied. The crystal growth of calcium phosphates was regulated by regenerated silk fibroin for 8 h (at pH 4.0, 7.0 and 10.0, respectively). Meanwhile, different concentrations of Ca²⁺ were employed at a certain pH value, keeping the initial Ca-P molar ratio constant at 1.67, i.e., the stoichiometry of hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HAP]. The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results demonstrated that, compared to pH 4.0 and 10.0, pH 7.0 promoted the transformation of brushite (CaHPO₄·2H₂O, DCPD) to HAP. In the composites of mineralized fibroin, DCPD is the main inorganic phase at both relatively low and high pH, while HAP is the main inorganic phase at pH 7.0. Additionally, the initial Ca-P concentration does not affect the kind of inorganic phase in the synthesized mineralized fibroin, but induce to different contents of inorganic mineral and different morphology of DCPD at pH 4.0 and pH 10.0.     

Na+,Ca2+和Al3+对聚丙烯酸钠的自组装行为的影响

采用荧光探针、动态光散射和透射电子显微镜研究了NaCl、CaCl<'2>和AlCl<.3>对水溶液中的聚丙烯酸钠(PAANa)自组装行为的影响.实验结果表明,在含有NaCl的聚丙烯酸钠水溶液中,分子链以线团形式存在;而Ca<'2+>或Al<'3+>与聚丙烯酸钠主链间通过静电相互作用自组装形成疏水胶束.当Ca<'2+>/...     

紫外激发蓝色荧光粉Sr2-x-yB5O9Cl:xEu2+,yTb3+的合成和发光性能

采用高温固相反应法合成Sr_2-x-yB₅O₉Cl:xEu²⁺,yTb³⁺蓝色荧光粉。用X射线衍射表征材料的晶体结构、用荧光光谱仪测定Eu²⁺和Tb³⁺的掺杂浓度,研究了助溶剂H₃BO₃过量浓度和反应温度对荧光粉发光性质的影响。结果表明,单掺杂Eu²⁺时,其浓度猝灭机理为电偶极-电偶极交互作用机制,浓度猝灭临界距离为R_C=1.71 nm。在紫外（230-410 nm）波段有强而宽的吸收带,表明此粉是一种近紫外白光LED用的蓝色荧光粉。     

Precision interferometric frequency measurement of the 674 nm2S1/2-2D5/2 transition in asingle cold Sr+ ion

The narrow linewidth 674 nm ²S_1/2-² D_5/2 transition in a cold Sr⁺ ion confined within an RF Paul trap has been probed using an optically narrowed 674 nm diode laser offset-locked to a second diode laser stabilized to a high-finesse ultra-low-expansion reference cavity. The transition frequency has been measured by means of interferometric comparison with an iodine-stabilized 633 nm He-Ne reference standard. A preliminary value for the ²S_1/2-²D_5/2 transition line center is 444 779 045 (9) MHz, limited by residual micromotion and low magnetic field Zeeman splitting     

Evaluation of judd-ofelt intensity parameters for sm3+ and Dy3+ in a laser liquid

From the reported absorption measurements the spectral intensities of the observed bands of Sm³⁺ and Dy³⁺ ions in a SeOCl₂ + SnCl₄ laser liquid are reported in this paper. The judd-Ofelt intensity (T₂,T₄,T₆) parameters have been evaluated by a least-squares fit method. From the magnitude of the bonding parameter (δ), it is suggested that the Sm³⁺ and Dy³⁺ ions in the laser liquid studied may be found to be covalent in nature. By applying the Judd-Ofelt theory, a good correlation has been established between the experimental and calculated spectral intensities of the ions studied.     

Eu2+、Dy3+、Li+共掺杂CaSi2O2N2荧光粉的发光性能

采用高温固相反应法制备了一系列白光LED用CaSi2O2N2:0.05Eu2+,xDy3+,xLi+(0≤x≤0.03)荧光粉.利用X射线衍射仪对样品的物相结构进行了分析,结果表明:Dy3+和Li+离子的掺入没有改变CaSi2O2N2:Eu2+荧光粉的主晶相.利用荧光光谱仪对样品的发光性能进行了测试,发现所有样品的激发光谱均覆盖了从近紫外到蓝光的较宽范围,400 nm激发下得到的发射光谱为宽波段的单峰,峰值位于545 nm左右,是Eu2+离子5d-4f电子跃迁引起的.Dy3+离子掺杂可以提高CaSi2O2N2:Eu2+荧光粉的发光强度,Dy3+与Li+共掺杂可进一步提高荧光粉的发光强度,当Dy3+和Li+的掺杂量为1mol%时,荧光粉的发光强度达到最大值,是单掺杂Eu2+的荧光粉发光强度的157%.