Liyong Wang

Hebei University, Pao-ting-shih, Hebei, China

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Publications (11)26.01 Total impact

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    ABSTRACT: BiPO4:Tb3+ green phosphors were synthesized by a polymer Mediated Solid-state method with Polyvinyl-alcohol (PVA). The morphology, crystal structure and composition of the samples were measured and characterized by SEM, XRD, and FT-IR methods. The results showed that different monoclinic phases could be controlled by PVA addition when calcination temperature reached 600 °C. A pure monoclinic phase was formed when annealing temperature was increased to 600 °C and calcination temperature could be another factor that affecting the samples' crystal structure. The luminescence properties of doping BiPO4 were measured by excitation and emission spectrum. And the characteristic emission bands 487, 542, 589 and 621 nm were corresponding to 5D4 → 7F6, 5D4 → 7F5, 5D4 → 7F4 and 5D4 → 7F3 transitions of Tb3+ ion. The strongest transition was at the band of 542 nm. The methodology discussed here is fundamentally important, which may provide an excellent platform for the phase-controlled synthesis and further optimized phosphors with the potential application in the fields of near UV-excited diodes.
    No preview · Article · Dec 2015 · Journal of Nanoelectronics and Optoelectronics
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    ABSTRACT: Eu3+ doped BiPO4 phosphors were synthesized via a facile precipitation method with surfactant-free environment. The X-ray diffraction results demonstrated that the samples possessed the different standard BiPO4 structure with dopants concentration and calcination temperature increases. Scanning electron microscopy images showed that the samples composed of well-dispersed, nanometer-sized crystals with spherical shape. The synthesized materials were characterized using other spectroscopic techniques such as FT-IR, Raman and Photoluminescence (PL). The difference in the symmetries and crystal structures is clearly reflected in the spectral results of multiphase doped BiPO4. The methodology discussed here is fundamentally important, which may provide an excellent platform for the phase-controlled synthesis and further optimized phosphors with the potential application in the fields of near UV-excited white-light-emitting diodes.
    No preview · Article · Apr 2015 · Journal of Nanoelectronics and Optoelectronics
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    ABSTRACT: Monodisperse barium tungstate (BaWO4) hierarchical ellipsoidal particles have been prepared via a simple citrate-assisted hydrothermal method. The as-synthesized particles are non-aggregated with narrow size distribution and are composed of closely packed nanoparticles. The possible formation process of the BaWO4 ellipsoids were investigated by time-dependent experiments. During the hydrothermal process, the chelating agent trisodium citrate plays a crucial role for the formation of BaWO4 hierarchical ellipsoidal particles. The as-synthesized BaWO4:Tb3+ phosphor shows intense green emission under ultraviolet light excitation, which may find potential applications in fields of fluorescent lamps, display systems, and optoelectronic devices. Moreover, this simple synthesis route may be of great significance in the preparation of other well-defined tungstate functional materials.
    No preview · Article · Apr 2014 · Science of Advanced Materials
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    ABSTRACT: Uniform and well-dispersed SrWO4 microspheres have been successfully synthesized through a hydrothermal method by using trisodium citrate and SDS as surfactants. XRD and SEM results demonstrate that the as-synthesized SrWO4 particles are high purity well crystallized and exhibit a relatively uniform spherical morphology. The as-obtained SrWO4:Ln3+ (Ln = Tb, Eu, Dy, and Sm) microspheres show intense light emissions with different colors coming from different Ln3+ ions under ultraviolet excitation, which might find potential applications in the fields such as light emitting phosphors, advanced flat panel displays, and light-emitting diodes (LEDs).
    No preview · Article · May 2013 · Journal of Nanoscience and Nanotechnology
  • Liyong Wang · Yongqiang Cheng · Hui Wang · Zhengping Li
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    ABSTRACT: Based on the high efficiency of fluorescence quenching and the different affinities of water-soluble carbon nanoparticles (CNPs) towards single-stranded DNA (ssDNA) and double-stranded DNA/RNA hybrid, a novel, rapid and cost-effective assay for detection of microRNA and nuclease activity was developed. The fluorescein-labeled ssDNA probe (FAM-P) could be adsorbed on the surface of CNPs through π-π stacking interaction giving rise to fluorescence quenching. By introduction of microRNA complementary to the DNA probe, the double-stranded DNA/miRNA hybrid could be formed and released from the surface of CNPs resulting in the fluorescence recovery. Thus, microRNA was successfully detected in homogenous fashion without any amplification or enzyme-involving reactions. Moreover, we demonstrated that the nuclease activities of RNase H and DNase I could also be sensitively monitored by using CNPs based on the fluorescence changing of the DNA probe. So, the CNPs provide an excellent homogeneous sensing platform for studying molecular diagnosis and therapeutics.
    No preview · Article · Jul 2012 · The Analyst
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    ABSTRACT: Ligase chain reaction (LCR) offers a simple and robust alternative platform for nucleic acid amplification, but its application has been limited because the LCR products are mostly detected by gel electrophoresis separation or heterogeneous analysis. In this paper, we report a novel homogeneous LCR assay by using cationic conjugated polymers (CCPs) as an indicator for detection of single-nucleotide polymorphism (SNP). For LCR, we design two pairs of unique target-complement probes. Each pair of probes contains two adjacent probes, in which one probe is designed with phosphorothioate modification at its 3'-end, and the other probe is labeled with fluorescein at its 5'-end. After the LCR, the two adjacent probes are ligated to form one DNA strand with a fluorescein label at its 5'-end and phosphorothioate modification at its 3'-end, which is resistant to the exonuclease I and exonuclease III degradation. When the CCP is added, because of the strong electrostatic interactions between CCP and DNA, effective fluorescence resonance energy transfer (FRET) from the CCP to the fluorescein-labeled DNA can be observed. In contrast, the unligated fluorescein-labeled probes are degraded to the mononucleotides by exonuclease I and exonuclease III. Introduction of CCP leads to inefficient FRET results because much weaker electrostatic interactions between the fluorescein-labeled mononucleotides and CCP keep the fluorescein far away from CCP. Accordingly, homogeneous LCR for SNP detection is performed successfully. The method is sensitive and specific enough to detect 1 fM (600 zmol) DNA molecules. It is possible to quantify SNP and accurately determine the allele frequency as low as 1.0%. This proposed assay strategy extends the application of LCR and provides a new platform for homogeneous detection of SNP.
    No preview · Article · Mar 2012 · Analytical Chemistry
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    ABSTRACT: Uniform and well-dispersed quasi-spherical YVO4:Ln3+ (Ln = Eu, Dy) nanoparticles have been successfully synthesized through a solvothermal approach using EG and PVP as solvent and surfactant, respectively. SEM and TEM images indicate that the as-obtained quasispheres are composed of tiny packed nanocrystallites. The YVO4:Eu3+ and YVO4:Dy3+ samples show strong red and yellow light emissions under ultraviolet excitation. The luminescence intensities of the phosphors are greatly enhanced by co-doping Ba2+ ions into the YVO4host lattice. Nitrogen adsorption–desorption measurements reveals that the as-synthesized luminescent quasi-spherical nanoparticles have a porous structure, which might find potential applications in the fields of luminescence, drug delivery, and disease therapy.
    Preview · Article · Dec 2011 · CrystEngComm
  • Guang Jia · Cuimiao Zhang · Shiwen Ding · Liyong Wang
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    ABSTRACT: Uniform upconversion luminescent gadolinium oxide hollow spheres were successfully synthesized via a homogeneous precipitation method with carbon spheres as template followed by a calcination process. During the annealing process, the carbon spheres template can be effectively removed and the amorphous precursor has converted to crystalline Gd2O3, which can be confirmed by the XRD and TG-DSC analysis. SEM and TEM images indicate that the Gd2O3 hollow spheres with diameters of 300-400 nm are uniform in size and distribution. The rare earth activator ions Ln3+-doped Gd2O3 hollow spheres exhibit intense upconversion luminescence with different colors under 980 nm light excitation, which may find potential applications in the fields such as drug delivery or biological labeling. Moreover, the upconversion luminescent mechanisms of the hollow spherical phosphors were investigated in detail.
    No preview · Article · Aug 2011 · Journal of Nanoscience and Nanotechnology
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    ABSTRACT: Well-dispersed lutetium oxide (Lu2O3) hollow spheres have been obtained by a template-directed method with carbon spheres as template followed by a heat treatment. The main synthesis process was carried out in aqueous condition without any organic solvents, surfactant, or etching agents. SEM and TEM images reveal that the Lu2O3 hollow spheres inherit the spherical shape and good dispersion of carbon spheres, and the shells of the hollow spheres are composed of a large amount of uniform nanoparticles. The lanthanide activator ions doped Lu2O3 hollow spheres show intense down- and upconversion luminescence with different colors under ultraviolet or 980nm light excitation, which may find potential applications in the fields of drug delivery or biological labeling. Furthermore, the luminescent mechanisms of the luminescent hollow spheres were investigated.
    No preview · Article · Jun 2011 · Journal of Alloys and Compounds
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    ABSTRACT: Polycrystalline BiFeO3 nanoparticles (size 30-50 nm) were prepared by a simple microwave synthesis technique. The nanoparticles were characterized by XRD, TEM and TG-DTA. The applied experiments show that they are very efficient for photo-catalytic decomposition of organic contaminants under irradiation ultraviolet frequency. The as-obtained BiFeO3 nanoparticles also demonstrate strong ferromagnetism of about 0.045 microB/Fe at room temperature, which is in good agreement with theoretical calculations.
    No preview · Article · Jun 2011 · Journal of Nanoscience and Nanotechnology
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    ABSTRACT: TiCl4 and MnSO4· H2O as raw materials are hydrolyzed stiochiometrically, following the intermediate of oxide hydrating reacts at 150°C, 0.5 MPa in high-pressure reactor, after filtering, washing and drying, nanometric TiO2-MnO2 (Ti1-X Mn X O2) is prepared. The effects of the reaction temperature and time on nanometric TiO2-MnO2 are also discussed. XRD shows that the product is TiO2-MnO2 with amorphous phase. After being sintered at above 780 °C, it transfers into Ti1-X Mn X O2 with a rutile structure. TEM shows that TiO2-MnO2 is the spherical particle. And the average diameter of the particles is 20 nm. The optical absorbance was determined by UV-265 spectrophotometer after dispersing the sample in the mixture of water and glycerol with the ratio of 1 : 1 equably. It is found that the nano-material possesses the advantages of both nano-TiO2 and nano-MnO2, and it has strong absorption in the UV and visible region. Photodegradation of dyes in an aqueous solution is investigated using nanometricTiO2-MnO2 as a photocatalyst. The results show that after 60 min illumination, the decolorization rate of the acidic red B and acidic black 234 dye can be as high as 100%.
    No preview · Article · Jan 2003 · Science in China Series B Chemistry