State Key Laboratory of Superhard Materials
State Key Laboratory of Superhard Materials
Li F.,State Key Laboratory of Superhard Materials
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2016
Electroactive polyamides containing dense oligoaniline functionalizations (PAs) were synthesized via oxidative coupling polymerization followed by postpolymerization functionalization, and exhibit excellent solubility, good thermal stability and reversible electroactivity. Interesting spectroscopic changes that occurred through chemical oxidation have been shown, which demonstrate the potential of PAs as an electrochromic material. As a result, the electrochromic behaviors of PAs were investigated in detail, exhibiting high contrast value, moderate switching time, and satisfactory coloration efficiency. Tunable conductive and dielectric properties have also been accomplished by varying the incorporation of oligoaniline segments. © 2016 Wiley Periodicals, Inc.
Wu Y.-L.,State Key Laboratory of Superhard Materials |
Wu Y.-L.,Jilin University |
Liu T.-Y.,Jilin University |
Sun C.-L.,State Key Laboratory of Superhard Materials |
And 4 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2013
The resonance Raman spectra of nonpolar molecule all-trans-β-carotene and polar molecule canthaxanthin in nonpolar CS2 and polar 1, 2-dicholoroethane in a temperature range from 243 K to 293 K are measured. The results show that polarities of the solute and solvent have a great effect on Raman spectrum. Raman scattering cross-section of nonpolar all-trans-β-carotene in nonpolar solvent CS2 is biggest and its bandwidth is narrowest. Raman scattering cross-section of polar canthaxanthin in polar solvent 1, 2-dicholoroethane is smallest and its bandwidth is widest. The experimental phenomena are explained by solvent effects, coherent weakly damped electron-lattice vibration and effective conjugated length. © 2013 Chinese Physical Society.
Sun Y.,Jilin University |
Sun Y.,State Key Laboratory of Superhard Materials |
Sun Y.,Key Laboratory of Drilling and Exploitation Technology |
Wu H.,Jilin University |
And 12 more authors.
Materials | Year: 2016
Metal matrix-impregnated diamond composites are widely used in diamond tool manufacturing. In order to satisfy the increasing engineering requirements, researchers have paid more and more attention to enhancing conventional metal matrices by applying novel methods. In this work, ZrO2 nanoparticles were introduced into the WC-bronze matrix with and without diamond grits via hot pressing to improve the performance of conventional diamond composites. The effects of ZrO2 nanoparticles on the microstructure, density, hardness, bending strength, and wear resistance of diamond composites were investigated. The results indicated that the hardness and relative density increased, while the bending strength decreased when the content of ZrO2 nanoparticles increased. The grinding ratio of diamond composites increased significantly by 60% as a result of nano-ZrO2 addition. The enhancement mechanism was discussed. Diamond composites showed the best overall properties with the addition of 1 wt % ZrO2 nanoparticles, thus paving the way for further applications. © 2016 by the authors.
Ouyang S.-L.,State Key Laboratory of Superhard Materials |
Ouyang S.-L.,Jilin University |
Li Z.-W.,Jilin University |
Chen Y.-Z.,Jilin University |
And 3 more authors.
Chemical Research in Chinese Universities | Year: 2011
Raman spectra and ultraviolet-visible(UV-Vis) absorption spectra of linear polyene molecule-canthaxanthin in n-hexane are measured and analyzed. In addition, the optimized structure of canthaxanthin was calculated via density functional theory(DFT) functional B3LYP. With decreasing the concentration, Raman scattering cross section (RSCS) of fundamental frequency is extremely high, and the UV-Vis absorption bands become narrower. The results of coherent weakly damped electron-Lattice vibration model were analyzed.
Qu G.-N.,State Key Laboratory of Superhard Materials |
Qu G.-N.,Jilin University |
Li D.-F.,Jilin University |
Li Z.-L.,Jilin University |
And 8 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2010
We have measured the UV-visible absorption and Raman spectra of β-carotene which contains 9 CC conjugated double bond polyenes biological molecules in 9 kinds of solvents. The results showed that the Raman scattering cross-section for C-C and C=C stretching vibration bands of β-carotene increases linearly with the increase of solvent density. The mechanism is that β-carotene in high density solvent is less affected by perturbation, has higher structure order, more extended π electron delocalization, and stronger coherent weakly damping C-C bond vibration, which results in a large Raman scattering cross section. Studies on the influence of solvent density to molecular Raman cross section have not been reported. This paper is promising as on experimental hint on theoretical study of light scattering, and provides a reference for research of polyenes chain molecules and the development of optoelectronic devices. © 2010 Chin. Phys. Soc.
Wang Y.,Jilin University |
Liu F.,Jilin University |
Hua Y.,Hainan Normal University |
Wang C.,Hainan Normal University |
And 3 more authors.
Journal of Colloid and Interface Science | Year: 2016
Tb3+ doped BiVO4 has been successfully synthesized by a simple microwave-assisted hydrothermal method at 140 °C for 30 min. The structure, morphology and optical property of the Tb3+ doped BiVO4 products have been systematically investigated. This study indicates that the incorporation of Tb3+ could induce the conversion of structure from monoclinic to tetragonal for BiVO4. Furthermore, the as-obtained Tb3+ doped BiVO4 samples showed an obvious morphological change: the hollow square rod-like BiVO4 crystal gradually changed to spindle-like crystal. The Tb3+ doped BiVO4 products exhibited extraordinary photocatalytic activity for Methylene Blue (MB) degradation under visible light irradiation. The doped BiVO4 at a molar ratio of 2 at% (Tb and Bi) with a mixture of monoclinic and tetragonal phases showed and prominent photocatalytic degradation rate, which reached 99.9% in 120 min. The results suggest that the differences in the photocatalytic activity of these BiVO4 crystals with different Tb3+ doping concentrations can be attributed to the change of crystalline phases, and the coexistence of the monoclinic/tetragonal phases in BiVO4 products, which improve the efficient charge separation and transportation. © 2016
Yang J.-G.,State Key Laboratory of Superhard Materials |
Yang J.-G.,PLA Air Force Aviation University |
Sun C.-L.,Jilin University |
Yang Y.-B.,PLA Air Force Aviation University |
And 4 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2012
Fermi resonance (FR) plays an important role in the spectral line identification and assignment in spectral analysis. It contains a wealth of physical laws which are urgently needed for research. In the present paper, we propose a new method of varying the refractive index of the solution to study the FR, which is based on the model of Onsager. The basic principle of this method is to use Raman scattering intensity (Raman scattering coefficient) changing with the refractive index of solution to study the FR. With this method we not only can give the relationship between the FR parameters and the refractive index of solution, but also find new spectrum phenomena (including the asymmetric shift of Fermi doublet and the FR tuned fundamental freguency of the overtone). In this article we provide a new research method to study the FR. © 2012 Chinese Physical Society.
Zhao S.,State Key Laboratory of Superhard Materials |
Zhao S.,Jilin University |
Zhang W.,State Key Laboratory of Superhard Materials |
Wang S.,Jilin University |
And 7 more authors.
Gaodeng Xuexiao Huaxue Xuebao/Chemical Journal of Chinese Universities | Year: 2014
Hydrogenated graphite/graphene nanostructures(HGNSs) were synthesized via a solvothermal route at 180 °C using potassium as the reductant and halogenobenzene(bromobenzene and dibromobenzene) as the carbon precursor. Selective cleavage of the relatively lower stable C-Br bonds(compared to C-H bonds) of the carbon precursor(C6H5Br and C6H4Br2, respectively) by K metal results in the growth of hydrogenated carbon nanostructures. The HGNSs grow through the polymerization and bonding of the remained hexagonal carbon rings after the debromination. The samples synthesized using C6H5Br and C6H4Br2 as carbon precursor are visually tawny and black, respectively. Raman and infrared spectra of the samples show that the black product is hydrogenated graphite nanosheets with the size of about 2 nm, while the tawny sample has smaller size. X-Ray diffraction(XRD) measurements show that the products are stacked in a rhombohedral structure, but with low crystallinity. Photoluminescence(PL) measurements of the samples reveal that the fluorescence intensity and energy are related to the size of the formed HGNSs. The fluorescence intensity of the tawny pro-duct is about 15 times higher than that of the black one under the same experimental conditions. A photoluminescence mechanism similar to that of graphite oxide has been proposed for the HGNSs.
PubMed | Jilin University, Hainan Normal University and State Key Laboratory of Superhard Materials
Type: | Journal: Journal of colloid and interface science | Year: 2016
Tb(3+) doped BiVO4 has been successfully synthesized by a simple microwave-assisted hydrothermal method at 140C for 30min. The structure, morphology and optical property of the Tb(3+) doped BiVO4 products have been systematically investigated. This study indicates that the incorporation of Tb(3+) could induce the conversion of structure from monoclinic to tetragonal for BiVO4. Furthermore, the as-obtained Tb(3+) doped BiVO4 samples showed an obvious morphological change: the hollow square rod-like BiVO4 crystal gradually changed to spindle-like crystal. The Tb(3+) doped BiVO4 products exhibited extraordinary photocatalytic activity for Methylene Blue (MB) degradation under visible light irradiation. The doped BiVO4 at a molar ratio of 2at% (Tb and Bi) with a mixture of monoclinic and tetragonal phases showed and prominent photocatalytic degradation rate, which reached 99.9% in 120min. The results suggest that the differences in the photocatalytic activity of these BiVO4 crystals with different Tb(3+) doping concentrations can be attributed to the change of crystalline phases, and the coexistence of the monoclinic/tetragonal phases in BiVO4 products, which improve the efficient charge separation and transportation.
Wang L.,State Key Laboratory of Superhard Materials |
Ke F.,HIGH-TECH |
Li Y.,State Key Laboratory of Superhard Materials |
Wang Q.,Shandong Key Laboratory of Optical Communication Science and Technology |
And 6 more authors.
Physica Status Solidi (B) Basic Research | Year: 2016
Theoretical and experimental methods have been conducted to study the high-pressure structures of CaWO4, which have never been definitely determined during the past decades. By using the CALYPSO method, in addition to the previously known tetragonal scheelite structure (I41/a), monoclinic fergusonite structure (I2/a), and the orthorhombic structure (Cmca) predicted by previous works, we have found two other new phases of CaWO4 at higher pressure: monoclinic P21/c and P21/m structures. Although the P21/c structure has the lowest energy (above 26.0GPa), synchrotron-radiation-based X-ray diffraction measurements show that only the P21/m structure stably exists above 38.0GPa. The kinetical hindrance of P21/c structure formation in the experiment has been attributed to its larger W-O coordination number than that of the P21/m structure at high pressure. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.