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1.
Chao Zhang Xiao-Jia Chen Yan-Ling Li Viktor V. Struzhkin Russell J. Hemley Ho-Kwang Mao Rui-Qin Zhang Hai-Qing Lin 《Journal of Superconductivity and Novel Magnetism》2010,23(5):717-719
The electronic properties, lattice dynamics, and electron–phonon coupling of the Cmmm phase of GeH4 have been studied by first-principle calculations using density functional perturbation theory. The electronic band structure shows the Cmmm phase metallic nature. It is found strong electron phonon interaction, and the superconducting critical temperature, predicted by Allen–Dynes modified McMillan equation, is about 40 K at 20 GPa. 相似文献
2.
V. A. Krylov P. G. Sennikov O. Yu. Chernova T. G. Sorochkina A. Yu. Sozin L. A. Chuprov S. A. Adamchik A. P. Kotkov 《Inorganic Materials》2008,44(7):766-772
We have developed analytical techniques for the determination of impurities in isotopically enriched 28SiH4 and 28SiF4. The impurities in SiF4 were first determined by IR spectroscopy, and those in SiH4, by gas chromatography/mass spectrometry. High-sensitivity determination of organic impurities in SiH4 and SiF4 was performed by gas chromatography. SiF4 was found to contain C1–C4 hydrocarbons, hexafluorodisiloxane (Si2F6O), hydrogen fluoride, trifluorosilanol (SiF3OH), fluorosilanes, water, and carbon oxides. The impurities identified in SiH4 include C1–C4 hydrocarbons, disilane (Si2H6), inorganic hydrides, Si2H6O, alkylsilanes, and fluorinated and chlorinated organics. The detection limits of IR spectroscopy were 3 × 10?3 to 5 × 10?5 mol %, those of gas chromatography/mass spectrometry were 8 × 10?6 to 10?8 mol %, and those of gas chromatography were 6 × 10-6 to 2 × 10?7 mol %. 相似文献
3.
We have synthesized materials based on a silver titanium phosphate with partial substitution of tri-, tetra-, or pentavalent
cations for titanium: Ag1±x
Ti2−x
M
x
(PO4)3 (M = Nb5+, Ga3+) and AgTi2−x
Zr
x
(PO4)3. The materials have been characterized by X-ray diffraction and impedance spectroscopy and have been shown to have small
thermal expansion coefficients. Their ionic conductivity has been determined. Silver ions in these materials are difficult
to replace with protons. 相似文献
4.
Xiao-Yu Sun Zheng He Xuan Gu 《Journal of Materials Science: Materials in Electronics》2018,29(20):17217-17221
Zn2GeO4, Zn2GeO4:Mn2+, Zn2GeO4:Pr3+ and Zn2GeO4:Mn2+/Pr3+ phosphors were fabricated by a solid state reaction. The phase and luminescent properties of the fabricated phosphors were investigated. The XRD patterns show that all of the fabricated phosphors have an orthorhombic structure. The fabricated Zn2GeO4 shows an emission band in the range of 350–550 nm. The fabricated Zn2GeO4:Mn2+ and Zn2GeO4:Pr3+ phosphors show emission bands corresponding to Mn2+ and Pr3+ ions, respectively. The fabricated Zn2GeO4:Mn2+/Pr3+ phosphor shows the emission band results from Mn2+ and the codoped Pr3+ enhances the emission intensity of Mn2+. Moreover, Zn2GeO4:Mn2+/Pr3+ phosphor exhibits longer decay time than that of Zn2GeO4:Mn2+. The higher intensity and longer lifetime of Mn2+ emission are induced by the energy transfer from Pr3+ of various vacancies to Mn2+ in Zn2GeO4:Mn2+/Pr3+ phosphors. 相似文献
5.
T. N. Khamaganova T. G. Khumaeva A. K. Subanakov A. V. Perevalov 《Inorganic Materials》2017,53(1):81-85
Polycrystalline samples of undoped, terbium-doped (CdB4O7:Tb3+), and manganese-doped (CdB4O7:Mn2+) cadmium tetraborate have been prepared by solid-state reactions at 850°C. Using differential scanning calorimetry and X-ray diffraction, we have determined the melting point of CdB4O7 (t m = 976°C) and shown that this compound melts incongruently. The observed monotonic decrease in the orthorhombic cell parameters of the doped materials indicates the formation of substitutional solid solutions (sp. gr. Pbca). The thermoluminescence intensity of the doped materials has been shown to depend on the nature and concentration of the activators and the irradiation time. 相似文献
6.
The spectral parameters of Er3+ in Yb3+/Er3+:KY(WO4)2 crystal with space group C2/c have been investigated based on Judd-Ofelt theory. The spectral parameters were obtained: the intensity parameters are: 2 = 6.33 × 10–20 cm2, 4 = 1.35 × 10–20 cm2, 6 = 1.90 × 10–20 cm2. The radiative lifetime and the fluorescence branch ratios were calculated. The emission cross section e (at 1536 nm) is 2.0 × 10–21 cm2. 相似文献
7.
Ada López Mariana G. da Silva Elisa Baggio-Saitovitch Alexandre R. Camara Raimundo N. SilveiraJr. Raul José Mauricio da Fonseca 《Journal of Materials Science》2008,43(2):464-468
Samples of SrAl2O4 and SrAl2O4:Cr3+ were prepared by mixing the powder materials SrCO3, Al2O3, and Cr2O3. The crystal structures of the undoped and doped samples were analyzed by X-ray diffraction (XRD) measurements. The diffraction
patterns reveal a dominant phase, characteristic of the monoclinic SrAl2O4 compound and another unknown secondary phase, in small amount, for doped samples. The data were fitted using the Rietveld
method for structural refinements and lattice parameter constants (a, b, c, and β) were determined. Luminescence of Cr3+ ions in this host is investigated for the first time by excitation and emission spectroscopy at room temperature. Emission
spectra present a larger band and a smaller structure associated to the
and electronic transitions, respectively. The obtained results are analyzed by crystal-field theory and the crystal-field parameter,
Dq, and Racah parameters, B and C, are determined from the excitation measurements. 相似文献
8.
Xiaochun Zhou Xiaojun Wang Renyun Kuang Jin Guo Hongmei Chen 《Inorganic Materials》2010,46(11):1244-1247
Different crystalline Ca3(VO4)2 nanocrystals have been synthesized successfully via a facile low temperature method with lithium addition. After different
ration of Li+ doping into the Ca3(VO4)2: Eu3+ host, the crystallinity of the sample becomes different, resulting in different of luminescence intensity of the characteristic
emission of Eu3+ ions. This approach provides economically viable route for large-scale synthesis of this kind of nanomaterials. 相似文献
9.
Ce3+/Mn2+ singly doped and codoped Mg2Al4Si5O18 phosphors were synthesized by a solid state reaction. The phase, luminescent properties and thermal stability of the synthesized phosphors were investigated. Ce3+ and Mn2+ singly doped Mg2Al4Si5O18 phosphors show emission bands locating in blue and yellow–red regions, respectively. In Ce3+ and Mn2+ codoped Mg2Al4Si5O18, tunable luminescence was obtained because of the energy transfer from Ce3+ to Mn2+. In Mg2Al4Si5O18:Ce3+/Mn2+ phosphors with a fixed Ce3+ concentration, energy transfer efficiency increases with the increasing Mn2+ concentration, which is confirmed by the continually decreasing intensity and shortening decay time of Ce3+ emission. Moreover, the luminescent properties and thermal stability provide a great significance on the applications in the field of light emitting diodes. 相似文献
10.
Emission spectral results of Pr3+ & Ho3+ ions doped Ca4GdO(BO3)3 powder phosphors are reported here. XRD, SEM and FTIR measurements have been carried out for them. The emission spectrum
of Pr3+: Ca4GdO(BO3)3 has shown an emission transition 1D2 → 3H4 at 606 nm with λexci = 480 nm (3H4 → 3P0) and Ho3+: Ca4GdO(BO3)3 phosphor has shown an emission transition 5S2 → 5I8 at 549 nm with λexci = 447 nm (5I8 → 5F1). Emission performances of these two phosphors have been explained in terms of energy level diagrams. 相似文献
11.
Yan-Hua Song Hai-Feng Zou Shu-Cai Gan Yue-Feng Deng Guang-Yan Hong Jian Meng 《Journal of Materials Science》2007,42(13):4899-4904
A red long lasting phosphor Zn3(PO4)2:Mn2+,Ga3+ (ZPMG) was prepared by ceramic method, and phase conversion and spectral properties were investigated. Results indicated
that the phase conversion from α-Zn3(PO4)2, β-Zn3(PO4)2 toγ-Zn3(PO4)2 occurs with different manganese concentration incorporated and sinter process. The structural change induced by the phase
transformation results in a remarkable difference in the spectral properties. The possible luminescence mechanism for this
red LLP with different forms has been illustrated. 相似文献
12.
A. N. Georgobiani B. G. Tagiev O. B. Tagiev S. A. Abushov F. A. Kazymova T. Sh. Gashimova Xu Xurong 《Inorganic Materials》2009,45(2):116-122
The photoluminescence (PL) spectra and Eu2+ excited state lifetime of EuGa2S4 and EuGa2S4:Er3+ have been studied in the range 78–500 K. The spectra show a band at 545 nm, due to the 4f 65d → 4f 7(8 S 7/2) transition. With increasing temperature, the full width at half maximum Γ(T) of the PL band of EuGa2S4 and EuGa2S4:Er3+ crystals increases from 0.15 to 0.22 and from 0.13 to 0.19 eV, respectively. Over the entire temperature range studied, Γ(T) is a linear function of T 1/2. The 545-nm emission intensity and Eu2+ excited state lifetime in EuGa2S4 and EuGa2S4:Er3+ vary exponentially with temperature. The luminescence quenching energies evaluated from the Arrhenius plots of I(103/T) and τ(103/T) coincide (0.10 eV) within the error of determination. 相似文献
13.
A series of Pr3+, Gd3+ and Pr3+–Gd3+-doped inorganic borate phosphors LiSr4(BO3)3 were successfully synthesized by a modified solid-state diffusion method. The crystal structures and the phase purities of samples were characterized by powder X-ray diffraction. Surface morphology of the sample was studied by scanning electronic microscopy (SEM). The optimal concentrations of dopant Gd3+ ions in compound LiSr4(BO3)3 were determined through the measurements of photoluminescence (PL) spectra of phosphors. Gd3+-doped phosphors LiSr4(BO3)3 show strong band absorption in UV spectral region and narrow-band UVB emission under the excitation of 276 nm was only due to 6P J → 8S7/2 transition of Gd3+ ions. The effect of Pr3+ ion on excitation of LiSr4(BO3)3:Gd3+ was also studied. The excitation of LiSr4(BO3)3:Gd3+, Pr3+ gives a broad-band spectra, which show very good overlap with the Hg 253.7 nm line. The photoluminescence spectra of LiSr4(BO3)3 with different doping concentrations Pr3+ and keeping the concentration of Gd3+ constant at 0.03 mol have also been studied. The emission intensity of LiSr4(BO3)3:Pr3+–Gd3+ phosphors increases with increasing Pr3+ doping concentration and reaches a maximum at 0.01 mol. From the photoluminescence study of LiSr4(BO3)3:Gd3+, Pr3+ we conclude that there was efficient energy transfer from Pr3+→ Gd3+ ions in LiSr4?x?y Pr x Gd y (BO3)3 phosphors. 相似文献
14.
T. G. Sorochkina A. D. Bulanov A. Yu. Sozin O. Yu. Chernova 《Inorganic Materials》2017,53(12):1300-1306
The impurity composition of 28SiF4 has been studied for the first time by gas chromatography/mass spectrometry using gas-adsorption capillary columns. For identification and determination of impurity substances by gas chromatography/mass spectrometry, we have proposed using cryogenic preconcentration of the impurities from 28SiF4. The presence of C2–C4 hydrocarbon impurities and sulfur hexafluoride has been confirmed. We have identified 35 impurity substances in 28SiF4, including linear and branched C5–C8 saturated hydrocarbons, aromatic hydrocarbons, chlorine- and fluorine-containing hydrocarbons, and silicon- and sulfur-containing substances, of which 28 have been detected for the first time. 相似文献
15.
G. V. Tikhonov 《Radiochemistry》2009,51(3):256-261
The effect of the synthesis conditions on the properties of inorganic laser-active liquids POCl3-SbCl5-235UO 2 2+ -Nd3+ is considered. The kinetic dependences of the U(IV) content and decay time of the Nd3+ luminescence in POCl3-SbCl5-235UO 2 2+ -Nd3+ solutions for various synthesis procedures at 380 K have been obtained. In POCl3-SbCl5-235UO 2 2+ -Nd3+ solutions, nonradiative energy transfer Nd3+ → U4+ is observed, and quenching of the Nd3+ luminescence is described by the Stern-Volmer law: k q = (6.4 ± 0.6) × 105 l mol?1 s?1. Laser liquids POCl3-SbCl5-235UO 2 2+ -Nd3+ with neodymium concentration of up to 0.7 M, uranyl concentration of up to 0.1 M, and decay time of the Nd3+ luminescence of up to 220 μs have been prepared for the first time. 相似文献
16.
The novel Ca4?x(PO4)2O: xDy3+ and Ca4?x?y(PO4)2O: xDy3+, yEu2+ multi-color phosphors were synthesized by traditional solid-state reaction. The crystal structure, particle morphology, photoluminescence properties and energy transfer process were investigated in detail. The X-ray diffraction (XRD) results demonstrate that the products showed pure monoclinic phase of Ca4(PO4)2O when x < 0.1. The scanning electron microscopy (SEM) indicated that the phosphors were grain-like morphologies with diameters of ~ 3.7–7.0 μm. Under excitation of 345 nm, Dy3+-doped Ca4(PO4)2O phosphors showed multi-color emission bands at 410, 481 and 580 nm originated from oxygen vacancies and Dy3+. Interestingly, Ca4(PO4)2O: Dy3+, Eu2+ phosphors exhibited blue emission band at 481 nm and broad emission band from 530 to 670 nm covering green to red regions. The energy transfer process from Dy3+ to Eu2+ was observed for the co-doped samples, and the energy transfer efficiency reached to 60% when Eu2+ molar concentration was 8%. In particular, warm/cool/day white light with adjustable CCT (2800–6700 K) and high CRI (Ra > 85) can be obtained by changing the Eu2+ co-doping contents in Ca4(PO4)2O: Dy3+, Eu2+ phosphors. The optimized Ca3.952(PO4)2O: 0.04Dy3+, 0.008Eu2+ phosphor can achieve the typical white light with CCT of 4735 K and CRI of 87. 相似文献
17.
Lei Yu Jigong Hao Zhijun Xu Wei Li Ruiqing Chu 《Journal of Materials Science: Materials in Electronics》2017,28(8):5840-5845
Novel green-emitting piezoelectric ceramics of SrBi4?x Er x Ti4O15 (SBT-xEr) were prepared. Strong up-conversion with bright green (524 and 548 nm) and a relatively weak red (660 nm) emission bands were obtained under 980 nm excitation at room temperature, which is attributed to the intra 4f–4f electronic transition of (2H11/2, 4S3/2)–4I15/2 and the transition from 4F9/2 to 4I15/2 of Er3+ ions, respectively. Simultaneously, Er3+ doping promotes the electrical properties. At 0.8 mol%Er, the optimal electric properties with high Curie temperature of T c?~527?°C, large remanent polarization of 2P r?~14.92 μC/cm2 and piezoelectric constant of d 33?~17 pC/N was achieved. As a multifunctional material, Er3+ doped SBT showed a great potential to be used in 3D-display, bio-imaging, solid state laser and optical temperature sensor. 相似文献
18.
Pure and Pb2+ doped SrB2O4 materials were prepared by a solution combustion synthesis method. The synthesized materials were characterized by using
the powder XRD and FTIR. The photoluminescence properties of Pb2+ doped SrB2O4 materials were investigated using spectrofluorometer at room temperature. The emission and excitation bands of SrB2O4: Pb2+ was observed at 363 and 270 nm, respectively. The dependence of the emission intensity on the Pb2+ concentration for SrB2O4: Pb2+ was investigated and the critical Pb2+ concentration was determined
The text was submitted by the authors in English. 相似文献
19.
A. N. Georgobiani B. G. Tagiev G. G. Guseinov T. G. Kerimova O. B. Tagiev S. G. Asadullaeva 《Inorganic Materials》2010,46(5):456-459
The structure of undoped and europium-doped ZnGa2Se4 has been studied, and the interplanar spacings, the Miller indices of the observed reflections, and their relative intensities
have been determined. The photoluminescence spectra of ZnGa2Se4 and ZnGa2Se4:Eu2+ crystals have been measured at temperatures from 77 to 230 K. The 566-nm band in the spectrum of ZnGa2Se4:Eu2+ is assigned to the Eu2+4f
65d→4f
7(8
S
7/2) electronic transition, and the bands at 591 and 646 nm are attributed to transitions of donor-acceptor pairs. 相似文献
20.
Yuguo Yang Bing Liu Yuanyuan Zhang Xianshun Lv Lei Wei Jianhua Xu Huadi Zhang Xuping Wang Cong Zhang Jing Li 《Journal of Materials Science: Materials in Electronics》2018,29(20):17154-17159
Mg2+/Ga3+ doped Y3Al5O12:Ce3+ phosphors were synthesized through a solid state reaction. The phase and luminescent of the synthesized phosphors were investigated. For Ga3+ codoped Y2.96Ce0.04Al(5?x)GaxO12 phosphors, the emission intensity increases with the increase of Ga3+ concentration up to Y2.96Ce0.04Al4.80Ga0.20O12 and then decreases with a further increase of Ga3+ concentration, but the emission peak shifts to shorter wavelength continuously in the Ga3+ doping concentration range of 0.05–0.25. For Mg2+/Ga3+ codoped Y2.96Ce0.04Al(4.8?y)Ga0.20MgyO12 phosphors, the emission intensity decreases and the emission peak shifts to longer wavelength continuously in the Mg2+ doping concentration range of 0.02–0.12. The emission spectra of Y2.96Ce0.04Al(4.8?y)Ga0.20MgyO12 phosphors demonstrate that the codoped Mg2+/Ga3+ ions not only induce the enhancement of Y2.96Ce0.04Al5O12 emission intensity but also lead to the red shift of Y2.96Ce0.04Al5O12 emission peak. The decay lifetimes decrease in Mg2+/Ga3+ codoped Y2.96Ce0.04Al5O12 phosphors due to defects formed by substitutions of Y3+ by Mg2+/Ga3+. 相似文献