K_2Ln(NO_3)_5·2H_2O(Ln=La,Ce,Pr,Nd,Sm)的晶体生长和热重-差热分析研究

本文生长出了K2Ln（NO3）5.2H2O（Ln=La；Ce；Pr；Nd；Sm）的单晶，并对其进行了晶体结构及差热-热重分析研究．结果表明，K2Ln（NO3）5.2H2O（Ln=La；Ce；Pr；Nd）的晶体属正交晶系，Fdd2空间群．首次生长出KPrN单晶并用直接法解出其晶体结构．解得KPrN的晶胞参数为：a=11．2210（10）,b=21．411（3），c=12．208（2）,Z=6；R=0．0240．对KLnN加热，则依次出现脱水、熔化、不可逆相变和NO的分解过程（K2Ce（NO3）5·2H2O除外）K2Ln（NO3）5·2H2O（Ln＝La；Nd；Sm）的NO分三步分解，K2Ln（NO3）5·2H。O（Ln=Ce；Pr）的NO分两步分解·KNO3和Ln（NO3）3·nH2O的混合物在225℃左右生成K2Ln（NO3）5     

Extraction Mechanism of Rare Earths with Sec-Octylphenoxy Acetic Acid by Two-Phase Titration Technique

Ｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓａｒｅｕｓｅｄｗｉｄｅｌｙｂｅ ｃａｕｓｅｏｆｔｈｅｉｒｓｐｅｃｉａｌｅｌｅｃｔｒｉｃａｌ,ｍａｇｎｅｔｉｃａｎｄｏｐｔｉｃａｌｎａｔｕｒｅｓ .Ｗｉｔｈｔｈｅｈｉｇｈ ｓｐｅｅｄｄｅｖｅｌｏｐ ｍｅｎｔｏｆｍｏｄｅｒｎｓｃｉｅｎｃｅａｎｄｔｅｃｈｎｏｌｏｇｙ ,ｔｈｅｎｅｅｄｆｏｒｒａｒｅｅａｒｔｈｓｗｉｔｈｈｉｇｈｐｕｒｉｔｙｉｓｉｎｃｒｅａｓ ｉｎｇ .Ｓｏｉｔｉｓｖｅｒｙｉｎｔｅｒｅｓｔｉｎｇｔｏｓｔｕｄｙｔｈｅｓｅｐａ ｒａｔｉｏｎａｎｄｐｕｒｉｆｉｃａｔｉｏｎｏ…     

Synthesis, Structure and Ionic Conductivity of La2／3-x Li3x MoO4

AlargenumberofM0 .5A0 .5M′O4 (M :rareearthion ,Bi3+,Fe3+,Cr3+,etc .A :alkaliion ,Cu+,Ag+,etc .M′ :Mo ,W )withtetragonalscheelite typestructurehavegoodcatalyticproperties .Aslumines centsubstrates ,theyhaveexcellentsensitizationtolu minescenceofrareearthion .Manyresearchesontheirstructure ,catalytic ,magneticandluminescentproper tieshavebeenmadesince 196 0s[1～ 10 ] .Thegeneralformulaforcompoundswiththetetragonalscheelite typestructureisAM′O4 wherethecationM′istetrahe drallycoordinat…     

杂质离子对Y_2O_3∶Eu~(3+)发光性能的影响

研究了碱金属及碱土金属离子掺杂的荧光体Y2 O3∶Eu3+ 0 .0 5,A+ 0 .0 2 (A =Li、Na、K)和Y2 O3∶Eu3+ 0 .0 5,B2 + 0 .0 2 (B =Mg、Ca、Sr、Ba)的荧光、余辉发光及热释光特性。余辉光谱数据表明 :杂质离子掺杂的荧光体Y2 O3∶Eu3+ 的余辉发射主峰与未掺杂荧光体Y2 O3∶Eu3+ 的荧光发射主峰 (611nm)一致 ,为经典Eu3+ 的5D0 7F2 电偶极跃迁 ;杂质离子的引入明显地延缓了Y2 O3∶Eu3+ 的余辉衰减 ,其中Y2 O3∶Eu3+ ,A+ (A =Li、Na、K)的余辉衰减趋势几乎完全一致 ,而Y2 O3∶Eu3+ 、B2 + (B =Mg、Ca、Sr、Ba)的余辉衰减趋势由慢到快依次为Ca、Sr、Ba、Mg。热释光谱数据显示 ,杂质离子的掺杂导致基质中电子陷阱能级的生成 ,这是导致余辉衰减减慢的直接原因。Y2 O3∶Eu3+ ,A+ 的热释峰都位于 175℃左右 ,相应电子陷阱能级深度为 0 .966eV左右 ;而Y2 O3∶Eu3+ ,B2 + 的热释峰由高到低分别位于 192℃ (Ca)、164℃ (Sr)、13 5℃ (Ba)、118℃(Mg) ,电子陷阱能级深度分别为 1.0 0 3eV(Ca)、0 .942eV(Sr)、0 .880eV(Ba)、0 .843eV(Mg)。结合余辉衰减数据 ,可以看到 ,Y2 O3∶Eu3+ ,A+ 和Y2 O3∶Eu3+ ,B2 + 的热释光谱与相应荧光体的余辉衰减趋势吻合得十分好 ,由此可以得出 ,一定相同的条件下 ,热释峰值温度越高 ,杂     

Photoluminescence and thermoluminescence properties of dysprosium doped zinc metaborate phosphors

Polycrystalline powder samples of dysprosium doped Zn（BO2）2 phosphors were prepared by solid state reaction in air at high temperature and characterized by X-ray powder diffraction. The IR, Photoluminescence （PL）, diffuse reflectance and three-dimensional （3D） thermoluminescence （TL） emission spectrum after 60^Co gamma ray irradiation were investigated. The characteristic 3D TL emission bands at about 425, 481 and 573 um with a main emission band of around 573 um were attributed to the host emission, 4^F9/2→6H15/2 and F9/2→6^H13/2 f-f transitions of Dy^3＋ ions. No emission from Dy^2＋ ions was observed in the measurement wavelength range. The TL-dose response of the Zn（BO2）2：Dy polycrystalline powder sample to gamma ray radiation in the range from 1 to 100 Gy at clinical dose levels was almost linear. The experimental results showed that Zn（BO2）2：Dy had potential use as the materials of gamma-ray thermoluminescence dosimeter （TLD） for clinical dosimetry.     

Luminescence properties of a new yellow long-lasting phosphorescence phosphor NaAlSiO_4:Eu~(2+),Ho~(3+)

A new aluminosilicate long-lasting phosphor with composition of NaAlSiO4:Eu2+,Ho3+ was synthesized and investigated. Under UV light excitation, the phosphor emitted yellow light corresponding to the characteristic emission of Eu2+ due to 5d-4f transition. Bright yellow phosphorescence sustaining for more than 30 min was observed after ceasing the excitation. The phosphorescence intensity decay obeyed a t–1 decay law, indicating a tunneling electron-hole recombination process in the phosphor. Four peaks appeared in the thermoluminescence curve and the ones at 322 and 370 K were thought to account for the long lasting phosphorescence at room temperature. The Ho3+ ion incorporated into the phosphor did not give any light but dramatically increased the intensities of both photoluminescence and phosphorescence via promoting defect levels in the phosphor.     

Preparation of ternary rare earth sulfide LaxCe2-xS3 as red pigment

In order to investigate the suitability of ternary rare earth sulfide LaxCe2-xS3 in plastic application as a red pigment,we prepared LaxCe2-xS3 via the sulfurization of the oxide powders using CS2 gas.In the sulfurization of LaxCe2-xS3,β-phase and γ-phase ternary rare earth sulfide LaxCe2-xS3 were synthesized at the sulfurization temperature of 1000 and 1250 oC for 3 h,respectively.The UV-vis absorption spectra of synthesized LaxCe2-xS3 showed that the absorption wavelengths of β-phase and γ-phase LaxCe2-xS3 samples were in the region of 617-670 nm and 607-653 nm,respectively.They were in red absorption region.Furthermore,the scanning electron microscopy(SEM)results of the synthesized LaxCe2-xS3 samples were investigated.The typical SEM micrographs indicated that the particle sizes of synthesized LaxCe2-xS3 were in the range of 0.5-6 μm.     

Bi~(3+)和Eu~(3+)在Y_3SbO_7中的发光性能

本文观察不同浓度的Eu~3和Bi~(3+)在具有立方晶系的Y_3SbO_7中发光性能及Bi~(3+)→Eu~(3+)的能量传递。Y_3SbO_7∶Eu~(3+)、Bi~(3+)磷光体在393nm激发下,Bi~(3+)将吸收紫外光的一部分能量传递给Eu~(3+),使其红光发射增强。其余的能量则以兰光(440nm)和绿光(540nm)发射。其“相对强度比”与合成温度有关,该磷光体可能是一种在多波段发光的新材料。     

K2Ln(NO3)5·2H2O(Ln=La,Ce,Pr,Nd,Sm)的晶体生长和热重-差热分析研究

本文生长出了K₂Ln（NO₃）₅·2H₂O（Ln=La；Ce；Pr；Nd；Sm）的单晶，并对其进行了晶体结构及差热-热重分析研究．结果表明，K₂Ln（NO₃）₅.2H₂O（Ln=La；Ce；Pr；Nd）的晶体属正交晶系，Fdd2空间群．首次生长出KPrN单晶并用直接法解出其晶体结构．解得KPrN的晶胞参数为：a=11．2210（10）A, b=21．411（3）A，c=12．208（2）A,Z=6；R=0．0240．对KLnN加热，则依次出现脱水、熔化、不可逆相变和NO的分解过程（K₂Ce（NO₃）₅·2H₂O除外）K₂Ln（NO₃）₅·2H₂O（Ln＝La；Nd；Sm）的NO分三步分解，K₂Ln（NO₃）₅·2H₂O（Ln=Ce；Pr）的NO分两步分解·KNO₃和Ln（NO₃）₃·nH₂O的混合物在225℃左右生成K₂Ln（NO₃）₅