ORCID Profile
0000-0001-5527-199X
Current Organisation
Northwestern Polytechnical University
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Publisher: Wiley
Date: 26-06-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CC09608B
Abstract: Unit cell volume collapse in Ba 2 BiRuO 6 , Ba 2 BiIrO 6 and Ba 2 BiOsO 6 when Bi( iii ) is oxidised to Bi( v ) by external applied pressure.
Publisher: AIP Publishing
Date: 08-2008
DOI: 10.1063/1.2966717
Abstract: MgTiO 3 ceramic s le was synthesized and its Raman spectra were recorded. The Raman-active vibrational modes of MgTiO3 were calculated using first-principle calculations (density functional theory). Based on experimental data and calculation results, the Raman peaks were assigned as 225 cm−1 (Ag), 306 cm−1 (Ag), 398 cm−1 (Ag), 500 cm−1 (Ag), 715 cm−1 (Ag) and 281 cm−1 (Eg), 328 cm−1 (Eg), 353 cm−1 (Eg), 486 cm−1 (Eg), 641 cm−1 (Eg). The assignment was supported by the polarized Raman spectrum. Meanwhile, the symmetry coordinates of MgTiO3 primitive cell were analyzed and employed to expand the Raman-active modes.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 08-2012
Publisher: IOP Publishing
Date: 04-2011
Publisher: Springer Science and Business Media LLC
Date: 15-09-2022
Publisher: American Chemical Society (ACS)
Date: 24-10-2022
Publisher: Elsevier BV
Date: 03-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM13852B
Publisher: Elsevier BV
Date: 04-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TC00965H
Abstract: The anion order of Y 4 Al 2 O 9 –Y 4 Si 2 O 7 N 2 solid solutions has been studied by the Rietveld refinement of neutron powder diffraction data. The luminescence properties of Ce 3+ doped Y 4 Al 2−2x Si 2x O 9−2x N 2x are also investigated.
Publisher: American Chemical Society (ACS)
Date: 09-04-2019
DOI: 10.1021/ACS.INORGCHEM.9B00406
Abstract: In situ synchrotron powder X-ray diffraction measurements have demonstrated that the isostructural AUO
Publisher: Wiley
Date: 02-07-2013
DOI: 10.1111/JACE.12429
Publisher: Informa UK Limited
Date: 03-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TA02328H
Abstract: Extensive diffuse scatter observed by single crystal neutron diffraction was modelled to gain insight into structural distortions in apatite-type lanthanum silicate.
Publisher: Elsevier BV
Date: 08-2019
Publisher: American Chemical Society (ACS)
Date: 27-04-2016
Publisher: Elsevier BV
Date: 04-2019
Publisher: American Chemical Society (ACS)
Date: 21-09-2020
Publisher: American Chemical Society (ACS)
Date: 13-07-2016
DOI: 10.1021/ACS.INORGCHEM.6B00923
Abstract: We report a new gaudefroyite-type compound YCa3(CrO)3(BO3)4, in which Cr(3+) ions (3d(3), S = 3/2) form an undistorted kagomé lattice. Using a flux agent, the synthesis was significantly accelerated with the typical calcining time reduced from more than 2 weeks to 2 d. The structure of YCa3(CrO)3(BO3)4 was determined by combined Rietveld refinements against X-ray and neutron diffraction data. Symmetry distortion refinement starting from a disordered YCa3(MnO)3(BO3)4 model was applied to avoid overparameterization. There are two ordering models, namely, K2-1 and K2-2, with the space groups P63 (No. 173) and P3̅ (No. 147), respectively, that differ in the [BO3] ordering between different channels (in-phase or out-of-phase). Both models give similarly good fits to the diffraction data. YCa3(CrO)3(BO3)4 is an insulator with the major band gap at Eg = 1.65 eV and a second transition at 1.78 eV. Magnetically, YCa3(CrO)3(BO3)4 is dominated by anti-ferromagnetic exchange along edge-sharing CrO6 octahedral chains perpendicular to the kagomé planes, with Θ ≈ -120 K and μeff ≈ 3.92 μB. The compound shows no spin ordering or freezing down to at least 2 K.
Publisher: American Physical Society (APS)
Date: 11-08-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4DT03336A
Abstract: We report the synthesis of new A 4 O 4 Se 3 (A = rare earth element) materials and identify three new structure types (β, γ, δ).
Publisher: American Chemical Society (ACS)
Date: 10-04-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP00084K
Abstract: Here, we have discovered a new high-pressure phase of Sb 2 O 3 , and reported pressure-induced anomalies in orthorhombic β-Sb 2 O 3 (valentinite) by the combination of synchrotron in situ X-ray diffraction and first-principles theoretical calculations up to 40.5 GPa.
Publisher: American Chemical Society (ACS)
Date: 14-02-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1RA07097E
Abstract: Ag 2 Mo 2 O 7 is an oxide solid-state Ag + electrolyte with the conductivity ∼5 × 10 −4 S cm −1 at 450 °C and carrier activation energy 0.88(3) eV.
Publisher: Elsevier BV
Date: 2011
Publisher: Springer Science and Business Media LLC
Date: 03-2022
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 03-2011
Publisher: Wiley
Date: 23-12-2021
DOI: 10.1111/JACE.17603
Publisher: IOP Publishing
Date: 06-2011
Abstract: MgTiO 3 ceramics were annealed in various atmospheres of air, O 2 and N 2 at a low temperature of 800 °C and the influences of annealing on the conductivity and microwave dielectric loss were investigated. The conductivity variation with the annealing atmosphere is consistent with the defect equilibrium 2O O × ↔2V O •• + O 2 ↑+ 2e', indicating n-type conductance for MgTiO 3 . Annealing in air/O 2 is favorable for eliminating oxygen vacancies and electron defects and thus decreases the conductivity. The N 2 -annealing increases the contents of oxygen vacancies and electron defects as well as the conductivity. Annealing in air/O 2 /N 2 reduced the microwave dielectric loss irrespective of the contrary effects of air/O 2 -annealing and N 2 -annealing on the defects and conductivity, suggesting the frozen defects associated with the oxygen loss during the high-temperature sintering and the low-temperature N 2 -annealing have negligible effects on microwave dielectric loss. Other factors, such as the release of thermally induced strain, may be responsible for the reduction of microwave dielectric loss due to the low-temperature annealing in air/O 2 /N 2 .
Publisher: Wiley
Date: 27-09-2010
Publisher: International Union of Crystallography (IUCr)
Date: 06-2017
DOI: 10.1107/S2052520617001123
Abstract: In this work we synthesized BaTaO 2 N and SrTaO 2 N using a two-step high-temperature solid-state reaction method and analysed the structural distortions, relative to the ideal cubic perovskite structure, according to group theory. From a complete distortion analysis/refinement using high-resolution neutron diffraction data in the temperature range 8 to 613 K, we identified tetragonal structures for BaTaO 2 N [ P 4/ mmm (No. 123)] and SrTaO 2 N [ I 4/ mcm (No. 140)]. In contrast to an anion-disordered cubic perovskite (Pm \\overline{3}m No. 221) with Ta at the cell center, both systems show a site preference for oxygen anions in the two opposite corners (along the c axis) of the Ta–O/N octahedra rather than the four square corners in the ab plane ( Γ 3 + occupancy distortion), which induces a tetragonal elongation of the unit cell with the c axis being longer than the a axis. A further Ta–O/N octahedra displacement [ R 5 − ( a ,0,0), rotation about the c axis] distortion was observed in SrTaO 2 N. This distortion mode is accompanied by an increased unit-cell distortion that decreases as the temperature increases. Ultimately a second-order phase transition caused by the loss of the R 5 − ( a ,0,0) mode was observed at 400–450 K.
Publisher: Royal Society of Chemistry (RSC)
Date: 20-10-2014
DOI: 10.1039/C4TC01966K
Publisher: Springer Science and Business Media LLC
Date: 24-06-2019
Publisher: Elsevier BV
Date: 06-2019
Publisher: Elsevier BV
Date: 12-2018
Publisher: Springer Science and Business Media LLC
Date: 19-08-2022
Publisher: AIP Publishing
Date: 06-2012
DOI: 10.1063/1.4732134
Abstract: We perform first-principles calculations of mechanical and electronic properties of silicene under strains. The in-plane stiffness of silicene is much smaller than that of graphene. The yielding strain of silicene under uniform expansion in the ideal conditions is about 20%. The homogeneous strain can introduce a semimetal-metal transition. The semimetal state of silicene, in which the Dirac cone locates at the Fermi level, can only persist up to tensile strain of 7% with nearly invariant Fermi velocity. For larger strains, silicene changes into a conventional metal. The work function is found to change significantly under biaxial strain. Our calculations show that strain tuning is important for applications of silicene in nanoelectronics.
Publisher: American Chemical Society (ACS)
Date: 24-04-2022
Abstract: The heterostructure and hierarchical morphology of carbonaceous absorbents play an important role in the construction of high-performance electromagnetic wave absorbing materials. Herein, novel micron-scale hard carbon particles with morphology heterogeneity were developed as lightweight superior electromagnetic wave absorbents via a facile and ecofriendly process. The as-prepared hard carbon particle composed of pseudographite and a highly disordered region shows a unique heterostructure. Concurrently, constructing a multilevel geometric shape and size can cause a decrease of the percolation threshold and an excellent balance between polarization and conduction loss, which enhances the electromagnetic wave absorption significantly. The composites (thickness
Publisher: AIP Publishing
Date: 04-2008
DOI: 10.1063/1.2903913
Abstract: A MgTiO3 ceramic s le was synthesized by solid-state reactions and its far infrared (IR) reflection spectrum recorded. The IR-active vibrational modes of MgTiO3 were calculated using first-principle calculations and the modes were represented by linear combinations of the symmetry coordinates. Using the eigenfrequencies obtained by the density functional theory calculations as initial values, we fitted the infrared reflection spectrum using the four-parameter semiquantum (FPSQ) model and the Lorentz three-parameter classical model. The parameters (ΩjTO, ΩjLO, γjTO, γjLO in FPSQ fitting and Ωj, Sj, γj in the three-parameter model fitting) of seven of the eight modes predicted by group theory analysis were obtained. The transverse optical modes (in FPSQ) are assigned as 279cm−1 (Au), 383cm−1 (Au), 472cm−1 (Au), 673cm−1 (Au) and ∼262cm−1 (Eu), 317cm−1 (Eu), 416cm−1 (Eu), 531cm−1 (Eu). The modes Au (279cm−1), Eu (317cm−1), Au (472cm−1), and Eu (531cm−1), which contain larger components of cation vibrations, contribute most to the microwave dielectric constant and dielectric loss.
Publisher: American Chemical Society (ACS)
Date: 05-2018
DOI: 10.1021/ACS.INORGCHEM.8B00463
Abstract: In situ synchrotron powder X-ray diffraction measurements have demonstrated that SrUO
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 12-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6SC02830F
Abstract: Pressure induced polymerization of CaC 2 in the amorphous phase is evidenced for the first time, accompanied by a 10 7 fold enhancement of the electrical conductivity.
Publisher: IOP Publishing
Date: 02-2013
Abstract: A new spinel compound, MgFeVO 4 , was prepared by solid-state reactions. On the basis of the Mössbauer spectrum, it can be deduced that both Fe and V in MgFeVO 4 are trivalent. Structure refinements based on X-ray and neutron diffraction data indicated that V 3+ ions are likely to occupy the octahedral site, whereas Fe 3+ and Mg 2+ ions take both octahedral and tetrahedral sites. The formula of the compound can be represented as (Mg 1- x Fe x )[Mg x Fe 1- x V]O 4 ( x =0.638). The transport measurements indicate that MgFeVO 4 is an n-type semiconductor with the hopping mechanism below 170 K and thermally activated mechanism at high temperatures. The DC and AC magnetic data show the antiferromagnetic interactions and spin glass behavior in MgFeVO 4 . The time-dependent magnetic relaxation and the exchange bias effect related to the spin glass phase are also analyzed. The curve fittings give long flipping times and large n values, indicating that strongly interacting clusters rather than in idual spins are the predominant spin glass features.
Publisher: American Chemical Society (ACS)
Date: 13-01-2015
DOI: 10.1021/IC502551N
Abstract: The quaternary transition metal oxyselenide Ce2O2ZnSe2 has been shown to adopt a ZrCuSiAs-related structure with Zn(2+) cations in a new ordered arrangement within [ZnSe2](2-) layers. The color of the compound changes as a function of cell volume, which can vary by ∼0.4% under different synthetic conditions. At the highest, intermediate, and lowest cell volumes, the color is yellow-ochre, brown, and black, respectively. The decreased volume is attributed to oxidation of Ce from 3+ to 4+, the extent of which can be controlled by synthetic conditions. Ce2O2ZnSe2 is a semiconductor at all cell volumes with experimental optical band gaps of 2.2, 1.4, and 1.3 eV for high, intermediate, and low cell volume s les, respectively. SQUID measurements show Ce2O2ZnSe2 to be paramagnetic from 2 to 300 K with a negative Weiss temperature of θ = -10 K, suggesting weak antiferromagnetic interactions.
Publisher: Springer Science and Business Media LLC
Date: 07-05-2008
Publisher: The Electrochemical Society
Date: 2009
DOI: 10.1149/1.3106058
Publisher: Elsevier BV
Date: 09-2011
Publisher: AIP Publishing
Date: 17-03-2014
DOI: 10.1063/1.4868226
Abstract: 1:2 B-site cation ordered Ba(Mg1/3Nb2/3)O3 ceramic was synthesized using conventional solid-state reaction at 1600 °C for 12 h. The structure parameters were obtained through Rietveld refinement of X-ray diffraction data. The Raman peak frequencies were obtained by Lorenz fitting on Raman spectrum. Four-parameter semiquantum model was used to fit the infrared (IR) reflectivity spectrum, and the fitted parameters were used to calculate the dielectric permittivity ε and dielectric loss tanδ. A total of 9 active Raman and 16 active IR modes were obtained using first-principle calculations based on density functional theory with local density approximation. All of the vibrational modes were assigned and represented by linear combinations of the symmetry coordinates deduced using group theory analysis. The Raman mode with the highest frequency A1g(4) (789 cm−1) can be described as the breathing vibration of NbO6. The IR modes Eu(1) (149 cm−1) and A2u(2) (212 cm−1), which can be described as the twisting vibrations of Ba–MgO6/Ba–NbO6 on the a–b plane and the stretching vibrations of Ba–MgO6/Ba–NbO6 along the c direction, respectively, are the dominant contributing modes to ε and tanδ. The dielectric property parameters obtained using IR spectrum fittings, first-principal calculations, and microwave measurements were compared.
Publisher: Elsevier BV
Date: 11-2021
Publisher: American Chemical Society (ACS)
Date: 22-07-2019
Publisher: American Chemical Society (ACS)
Date: 06-05-2010
DOI: 10.1021/IC100361Y
Abstract: The series BaBi(1-x)Ta(x)O(3) (0 <or= x <or= 0.5) has been synthesized by traditional solid-state reactions. Their structures are analyzed by the combinational use of X-ray, neutron, and converged-beam electron diffractions. They all crystallize in P1. FTIR and Raman data confirm that an inversion center is absent in the crystal structure of the series BaBi(1-x)Ta(x)O(3) (0 <or= x <or= 0.5). No obvious P-E (polarization-electrical field) loops are observed for them.
Publisher: American Chemical Society (ACS)
Date: 29-02-2012
DOI: 10.1021/IC202340Q
Abstract: A novel oxonitridosilicate phosphor host Sr(3)Si(2)O(4)N(2) was synthesized in N(2)/H(2) (6%) atmosphere by solid state reaction at high temperature using SrCO(3), SiO(2), and Si(3)N(4) as starting materials. The crystal structure was determined by a Rietveld analysis on powder X-ray and neutron diffraction data. Sr(3)Si(2)O(4)N(2) crystallizes in cubic symmetry with space group Pa ̅3, Z = 24, and cell parameter a = 15.6593(1) Å. The structure of Sr(3)Si(2)O(4)N(2) is constructed by isolated and highly corrugated 12 rings which are composed of 12 vertex-sharing [SiO(2)N(2)] tetrahedra with bridging N and terminal O to form three-dimensional tunnels to accommodate the Sr(2+) ions. The calculated band structure shows that Sr(3)Si(2)O(4)N(2) is an indirect semiconductor with a band gap ≈ 2.84 eV, which is close to the experimental value ≈ 2.71 eV from linear extrapolation of the diffuse reflection spectrum. Sr(3-x)Si(2)O(4)N(2):xEu(2+) shows a typical emission band peaking at ~600 nm under 460 nm excitation, which perfectly matches the emission of blue InGaN light-emitting diodes. For Ce(3+)/Li(+)-codoped Sr(3)Si(2)O(4)N(2), one excitation band is in the UV range (280-350 nm) and the other in the UV blue range (380-420 nm), which matches emission of near-UV light-emitting diodes. Emission of Sr(3-2x)Si(2)O(4)N(2):xCe(3+),xLi(+) shows a asymmetric broad band peaking at ~520 nm. The long-wavelength excitation and emission of Eu(2+) and Ce(3+)/Li(+)-doped Sr(3)Si(2)O(4)N(2) make them attractive for applications in phosphor-converted white light-emitting diodes.
Publisher: The Electrochemical Society
Date: 2008
DOI: 10.1149/1.2898897
Publisher: Wiley
Date: 30-08-2007
Publisher: American Chemical Society (ACS)
Date: 30-04-2015
DOI: 10.1021/ACS.INORGCHEM.5B00599
Abstract: A number of Ln2O2MSe2 (Ln = La and Ce M = Fe, Zn, Mn, and Cd) compounds, built from alternating layers of fluorite-like [Ln2O2](2+) sheets and antifluorite-like [MSe2](2-) sheets, have recently been reported in the literatures. The available MSe4/2 tetrahedral sites are half-occupied, and different compositions display different ordering patterns: [MSe2](2-) layers contain MSe4/2 tetrahedra that are exclusively edge-sharing (stripe-like), exclusively corner-sharing (checkerboard-like), or mixtures of both. This paper reports 60 new compositions in this family. We reveal that the transition-metal arrangement can be systematically controlled by either Ln or M doping, leading to an "infinitely adaptive" structural family. We show how this is achieved in La2O2Fe1-xZnxSe2, La2O2Zn1-xMnxSe2, La2O2Mn1-xCdxSe2, Ce2O2Fe1-xZnxSe2, Ce2O2Zn1-xMnxSe2, Ce2O2Mn1-xCdxSe2, La2-yCeyO2FeSe2, La2-yCeyO2ZnSe2, La2-yCeyO2MnSe2, and La2-yCeyO2CdSe2 solid solutions.
Publisher: Springer Science and Business Media LLC
Date: 20-06-2022
Publisher: Elsevier BV
Date: 11-2018
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Chun-Hai Wang.