scholarly journals Energy Transfer between Ce3+-Dy3+ in Ca2Al2SiO7: Ce3+, Dy3+ Phosphor

Author(s):  
Tien Do ◽  
Son Nguyen ◽  
Tuat Le ◽  
Liem Le

Ce3+ and Dy3+ ions doped Ca2Al2SiO7 (CAS) phosphors were prepared by the solid-state reaction at 12800C for 1h. X-ray diffraction patterns confirmed a tetragonal crystalline structure. The luminescent spectra of CAS: Ce3+, Dy3+ phosphors consist a board band with peaking at 420 nm corresponding to the luminescence of Ce3+ ions and narrow lines of Dy3+ ions. The energy transfer from Ce3+ ion to Dy3+ ion is presented and discussed

1987 ◽  
Vol 2 (3) ◽  
pp. 176-179 ◽  
Author(s):  
G. Wilson ◽  
F. P. Glasser

AbstractA systematic survey of phase formation in the Na2O-ZrO2-SiO2 system has revealed inconsistencies in the number and identity of ternary phases, and of their X-ray powder data. The phases Na2ZrSiO5, Na4Zr2Si3O12, Na2ZrSi2O7 and Na2ZrSi4O11 were prepared by solid-state reaction and their experimental X-ray diffraction patterns measured. Calculated X-ray diffraction patterns were generated by computer, using published crystallographic data, and critically compared with the experimentally observed values. The unit-cell constants were redefined to a greater accuracy than the presently accepted values published in the Powder Diffraction File. Only Na4Zr2Si3O12 produced an X-ray diffraction pattern which agreed with that previously published; those from the other phases were significantly different in both the intensities and positions of the reflections. Data for synthetic Na2ZrSi4O11 identical to the mineral vlasovite are reported.


2014 ◽  
Vol 29 (3) ◽  
pp. 254-259 ◽  
Author(s):  
Naoki Takani ◽  
Hisanori Yamane

CaTi1−xSnxO3 (x = 0.0–1.0) solid solutions were prepared by solid-state reaction at 1450 °C. Rietveld refinement of their powder X-ray diffraction patterns revealed that all the solid solutions crystallized in orthorhombic cells with the perovskite-type structure, the space group Pbnm. The refined unit-cell parameters linearly increased with nominal tin contents x.


RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25358-25367 ◽  
Author(s):  
Hanen Ghoudi ◽  
Souad Chkoundali ◽  
Zeineb Raddaoui ◽  
Abdelhedi Aydi

In this paper, the synthesis of Ca0.1Na0.9Ti0.1Nb0.9O3 (CNTN) ceramic by a solid-state reaction is reported. The results of Rietveld refinement of X-ray diffraction patterns at room temperature showed a pure tetragonal perovskite (P4mm space group).


2014 ◽  
Vol 1082 ◽  
pp. 57-60
Author(s):  
Jian Qing Li ◽  
Ling Feng Yu ◽  
Zi Peng Chen ◽  
Zheng Zheng Ma

Multiferroic ceramics of Bi5Ti3Fe1-xNixO15(x=0.1,0.2,0.5,0.7) are synthesized b the conventional solid state reaction, and their microstructure, magnetic properties are investigated. X-ray diffraction patterns show that a four-layer Aurivillus phase is formed in each sample and the diffraction peaks change obviously with the temperature increasing. The Ni ion modification induces remarkable ferromagnetism (FM) at room temperature. And the x=0.2 sample has the greatest saturation magnetization Ms~0.26552 emμ/g, and the coercive field Hc~ 0.65478 kOe


2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.


2012 ◽  
Vol 512-515 ◽  
pp. 158-161 ◽  
Author(s):  
Ling Dai ◽  
Qiang Xu ◽  
Shi Zhen Zhu ◽  
Ling Liu

As a new candidate material for the ceramic layer in thermal barrier coatings (TBCs) system, La3NbO7 was synthesized with La2O3 powder and Nb2O5 powder by solid state reaction. The stating powders with a mole ratio of La to Nb of 3:1 were mixed and then the mixture was calcined under the different temperatures(800°C, 1000°C, 1200°C) and dwell times(2h, 6h, 10h). The phase structure of the powder was observed by X–ray diffraction(XRD), and the microstructure of the sample was observed by scanning electron microscope(SEM). The effect of calcination temperature and dwell Time on the phase formation were examined. The results indicate that the La3NbO7 powder with single phase can be synthesized successfully at 1200°C for 10h in air, and the La3NbOsub>7 powders synthesized have an ultra-fine particle size of 0.5˜1µm with a granular particle shape. With the temperature increasing, LaNbO4/sub> was synthesized firstly and then La3NbO7 was synthesized with a mole ratio of La2O3 to LaNbO4 of 1:1.


Author(s):  
Hongqiang Cui ◽  
Yongze Cao ◽  
Lei Zhang ◽  
Yuhang Zhang ◽  
Siying Ran ◽  
...  

Er3+ with different concentrations doped K2Yb(PO4)(MoO4) phosphors were prepared by a solid-state reaction method, and the layered orthorhombic crystal structure of the samples was confirmed by X-ray diffraction (XRD). Under...


2021 ◽  
Vol 321 ◽  
pp. 23-27
Author(s):  
Simona Ravaszová ◽  
Karel Dvořák

The paper is focused on one of the most important component of Portland clinker-on the tricalcium silicate. The study reported in this article is focuses on the changes in crystallite size of synthetic tricalcium silicate obtained using solid state reaction method. Crystallite size changes are monitored during the grinding in three types of laboratory mills in two different conditions. Changing in crystallite size at various grinding time up to 120 minutes are studied with the aid of X-ray diffraction and using the Scherrer equation. It has been found that the most efficient laboratory mill in terms of speed and fineness of the material was the planetary mill.


2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Alpi Zaidah

Pembuatan sampel barium stronsium titanat (BaxSr1-xTiO3) telah dilakukan dengan metode solid state reaction. Variasi komposisi mol Ba(x) untuk pembuatan sampel adalah x=0,4;0,3 dan 0,2. Sampel di-sintering pada suhu 1100oC dengan holding time 2 jam. Karakterisasi sampel dilakukan menggunakan peralatan X-Ray Diffraction (XRD) untuk mengetahui tingkat kekristalan dan ukuran kristal dari sampel. Sedangkan untuk mengetahui besarnya konstanta dielektrik menggunakan RLC-Meter.  Berdasarkan analisa dengan software GSAS, parameter kisi BaxSr1-xTiO3 yang sintering pada suhu 1100°C untuk x=0,4 adalah a=b=c=3,947 nm. Parameter kisi a=b=c=3,947 nm untuk x=0,3, dan parameter kisi a=b=c=3,939 nm untuk x=0,2. Nilai parameter kisi a=b=c menunjukkan struktur kristal berbentuk kubik. Ukuran kristal berturut-turut untuk x=0,4;0,3 dan 0,2 adalah 65 nm, 66 nm dan 69 nm. Ukuran kristal semakin besar seiring dengan meningkatnya penambahan Sr. Pengukuran konstanta dielektrik (K) dilakukan pada rentang frekuensi 1 kHz. Nilai K sampel dengan x=0,4;0,3 dan 0,2 masing-masing sebesar 265, 277 dan 307.


2014 ◽  
Vol 6 (2) ◽  
pp. 217-231 ◽  
Author(s):  
F. Khatun ◽  
M. A. Gafur ◽  
M. S. Ali ◽  
M. S. Islam ◽  
M. A. R. Sarker

The lithium-cobalt oxide LixCoO2 is a promising candidate as highly active cathode material of lithium ion rechargeable batteries. The crystalline-layered lithium cobaltite has attracted increased attention due to recent discoveries of some extraordinary properties such as unconventional transport and magnetic properties. Due to layered crystal structure, Li contents (x) in LixCoO2 might play an important role on its interesting properties. LiCoO2 crystalline cathode material was prepared by using solid-state reaction synthesis, and then LixCoO2 (x<1) has been synthesized by deintercalation of produced single-phase powders. Structure and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), Infrared spectroscopy, Impedance analyzer etc. The influence of lithium composition (x) on structural, electronic and optical properties of lithium cobaltite was studied. Temperature dependent electrical resistivity was measured using four-probe technique. While LixCoO2 with x = 0.9 is a semiconductor, the highly Li-deficient phase (0.75 ? x ? 0.5) exhibits metallic conductivity. The ionic conductivity of LixCoO2 (x = 0.5 – 1.15) was measured using impedance spectroscopy and maximum conductivity of Li0.5CoO2 was found to be 6.5×10-6 S/cm at 273 K. The properties that are important for applications, such as ionic conductivity, charge capacity, and optical absorption are observed to increase with Li deficiency. Keywords: Calcination; Characterization; Inorganic compounds; Solid-State reaction; X-ray diffraction. © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v6i2.17900 J. Sci. Res. 6 (2), 217-231 (2014)  


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