Fraktionierte Kristallisation von Ammonium- und Magnesiumdoppelnitraten der Ceriterden; Bestimmung der Trennfaktoren und Vergleich der Trennwirkung

Summary The Separation Factors for Pr/La, Nd/Pr, and Sm/Nd, characterizing the crystallization of ammonium and magnesium double nitrates under practical conditions, were determined analytically and are discussed. They confirm that La and Pr can be separated better by fractional crystallization of ammonium double nitrates, whereas in the presence of Sm the magnesium double nitrates are preferable.

     

Etude de phosphates condenses diagramme d’equilibre du systeme AgPO3−Pr(PO3)3 Données sur AgPr(PO3)4

The AgPO₃?Pr(PO₃)₃ system has been studied for the first time by differential thermal analysis, X-ray diffraction and IR spectroscopy. The system shows one compound AgPr(PO₃)₄ which melts in a peritectic decomposition at 1069 K. An eutectic appears at 761 K. AgPr(PO₃)₄ belongs to the monoclinic system with space group P2_t/c,Z=4. The parameters of the unit cell are:a=12.000(9),b=13.177(4),c=7.046(5) Å and β=123^o,81(6),Z=4. Its IR absorption spectrum is typical of chain phosphates.     

真空紫外光激发下掺Pr3+铝酸盐的自陷激子对Pr3+发光的影响

研究了SrAl12 O19:Pr3+和Y3Al5O12(YAG):Pr3+在20K,77K和300K的真空紫外(VUV)光谱,二者除了表现出Pr3+特有的发射性质外,还产生了一种特殊的发射现象,即自陷激子(STE)发射,并且其随着稀土离子浓度和温度的降低而增强.还着重讨论了自陷激子对Pr3+发光的影响.     

Preparation, characterization and infrared emissivity study of helical polyurethane@SiO2 core-shell composite

Helical polyurethane@SiO₂ (HPU@SiO₂) core-shell composite was prepared after surface modification of SiO₂ nanoparticles. HPU@SiO₂ was characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet (UV) spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate that the helical polyurethane has been successfully grafted onto the surfaces of the modified SiO₂. HPU@SiO₂ composite exhibits clearly core-shell structure. The ultraviolet absorption and crystallizability of HPU@SiO₂ are changed due to the shell of helical polyurethane, which possesses regular single-handed conformation and inter-chain hydrogen bonds. The infrared emissivity of HPU@SiO₂ was also investigated. The result indicates that the interfacial interactions between organic shell and inorganic core induce the infrared emissivity value being reduced from 0.781 for SiO₂ to 0.503 for HPU@SiO₂.     

基于ZBLANⅩⅣPr,Yb频率上转换发光的三维立体显示

本文对利用ZBLANⅩⅣPr,Yb频率上转换发光的三维立体显示做了研究,探讨了其中的一些物理问题.在实验中,我们利用Yb³⁺离子敏化的方法提高Pr³⁺的上转换发光效率;通过降低能引起单频上转换发光的激光强度来提高寻址点和非寻址点在显示过程中的对比度.     

CaTiO3:Pr3+长余辉玻璃的制备与发光性能

用二次熔融法制备了CaTiO3：Pr^3＋红色长余辉玻璃。测量了样品的发射光谱,其发射光谱峰值为611．7,614．5nm,对应于Pr^3＋的4f-4f（^1D2→^3H4）跃迁,与CaTiO3：Pr^3＋晶态长余辉发光粉的发射光谱峰值相一致。玻璃粉与发光粉的质量配比在95：5～80：20时,都可以形成玻璃态并得到红色长余辉发光。研究了气氛和熔融温度对发光性能的影响,在空气环境下,800℃即可得到性能良好的样品。     

Statistical Interaction Term of One-Dimensional Anyon Models

A form of statistical interaction term of one-dimensional anyons is introduced, based on which one-dimensional anyon models are theoretically realized, and the statistical transmutation between bosons （or fermions） and anyons is established in quantum mechanics formalism. Two kinds of anyon models which are being studied are recovered and reexplained naturally in our formalism.     

Ca4LaNbMo4O20:Pr3+荧光粉的发光性质

采用高温固相法成功制备出荧光粉Ca₄LaNbMo₄O₂₀:Pr³⁺,通过X射线衍射分析了样品的结构,其结构与CaMoO₄结构相似。在Ca₄LaNbMo₄O₂₀:Pr³⁺的激发光谱中出现了NbO₄^3-和MoO₄^2-的电荷迁移(CTS)吸收和Pr³⁺离子的4f→4f5d激发跃迁,以及Pr³⁺-金属离子的价间电荷迁移(IVCT)吸收;另外在420~520 nm处,还观测到属于Pr³⁺离子的典型f-f激发跃迁。发射光谱中,在452 nm激发下,主要出现绿光和红光两种发射,其峰值位于490 nm和607 nm处,分别是Pr³⁺的³P₀→³H₄和¹D₂→³H₄的跃迁作用;在紫外287 nm激发下出现NbO₄^3-和MoO₄^2-发射和Pr³⁺离子的4f5d→4f跃迁宽带,以及Pr³⁺离子的4f→4f发射峰。