Papers by Author: Dong Lin Zhao

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Authors: Dong Lin Zhao, Hong Ye Zhao, Xian Wei Zeng, Qi Sheng Xia, Jin Tian Tang
1185
Authors: Dong Lin Zhao, Hong Feng Yin, Yong Dong Xu, Fa Luo, Wan Cheng Zhou
Abstract: Three-dimensional textile SiC fiber reinforced SiC composites with pyrolytic carbon interfacial layer (3D-SiC/C/SiC) were fabricated by chemical vapor infiltration. The microstructure and complex permittivity of the 3D textile SiC/C/SiC composites were investigated. The flexural strength of the 3D textile SiC/C/SiC composites was 860 MPa at room temperature. The real part (ε′) and imaginary part (ε″) of the complex permittivity of the 3D-SiC/C/SiC composites are 9.11~10.03 and 4.11~4.49, respectively at the X-band frequency. The 3D-SiC/C/SiC composites would be a good candidate for structural microwave absorbing material.
1028
Authors: Dong Dong Zhang, Dong Lin Zhao, Bin He
Abstract: Graphene nanosheets (GNSs) were mass-produced from flake natural graphite by oxidation, rapid expansion and ultrasonic treatment. The effects of ultrasonic times on the morphology and structure of GNSs and mechanical properties of GNS/epoxy nanocomposites were systematically investigated. GNS/epoxy nanocomposites were fabricated by ultrasonication and cast molding method. The mechanical properties of GNS/epoxy nanocomposites were influenced by the specific surface area, layer stacking and oxygen-containing functional group contents of GNSs. GNSs had excellent exfoliation degree when the sonication time was 15 h and there were some slightly changes on surface functional group comparing with 0 h sonication graphene and 5 h sonication graphene. When the sonication time was 15 h, the tensile strength and flexural strength of GNS/epoxy nanocomposites reached the highest value of 60.9 MPa and 91.33 MPa, which were increased by 25.3% and 30.94%, respectively, compared with pristine epoxy. The stress-strain curves of tensile testing demonstrated that extending the sonication time of GNSs can increased the fracture toughness of GNS/epoxy nanocomposites.
496
Authors: Hong Mei Chai, Dong Lin Zhao, Zeng Min Shen
Abstract: The carbon nanotube/PMMA/PVAc composite film was prepared by solution casting. The carbon nanotube (CNT) and graphitized carbon nanotube (GCNT) were employed as conductive fillers in the composite films. The conductivity of the GCNT/PMMA/PVAc film is better than that of CNT/PMMA/PVAc film. The electrical percolation thresholds were at 5wt% and 2wt% respectively in the CNT/PMMA/PVAc film and GCNT/PMMA/PVAc film. The volume electric resistivities of CNT/PMMA/PVAc and GCNT/PMMA/PVAc composite film are at 0.044⋅m and 0.007⋅m respectively at 15wt% carbon nanotube. The significant difference of resistivity for the both types of composite film was due to different structure and crystallinity of CNT and GCNT.
555
Authors: Dong Lin Zhao, Hong Mei Chai, Yun Fang Liu, Zeng Min Shen
Abstract: Thin films of poly(methyl methacrylate) (PMMA),poly(vinyl acetate) (PVAc) and carbon nanotube composites were produced by different coating methods. The best way to produce the carbon nanotube / PMMA / PVAc composite film with conductive network is dispersing carbon nanotubes in PMMA and PVAc by ultrasonic and by solution casting. Electrical resistance responses of carbon nanotube / PMMA / PVAc composite sensors against various organic vapors at low concentrations are investigated. The experimental results indicate that the composites have high selectivity to various organic vapors at the same concentration. In addition, the electric resistance response of the composites against organic vapors takes place in step with their vapor adsorption procedure. Compatible blends of poly(methyl methacrylate) and poly(vinyl acetate) would be a good candidate to produce a series of electrically conducting carbon nanotubes composite film whose resistance is sensitive to the nature and concentration of an analyte in the vapor phase. The results indicate that the carbon nanotube / PMMA / PAVc composite film can be used as a novel organic vapor sensor to detect, quantify and discriminate various organic vapors.
809
Authors: Liang Yu Li, Dong Lin Zhao, Dong Dong Zhang
Abstract: Graphene nanosheets (GNSs) were prepared from flake natural graphite by oxidation, rapid expansion and ultrasonic treatment. The morphology, structure and electrochemical performance of GNSs as electrode materials for supercapacitors were systematically investigated via high-resolution transmission electron microscopy, X-ray diffraction, nitrogen adsorption and desorption isotherms and a variety of electrochemical testing techniques. The electrodes with freestanding GNSs prepared by coating method exhibited good rate capability and reversibility at high scan rates in electrochemical performances. GNS electrode with specific surface area of 243 m2 g1 maintained a stable specific capacitance of 200 F g1 under specific current of 0.1 A g1 for 500 cycles of charge/discharge.
581
Authors: Feng Li, Dong Lin Zhao, Li Zhong Bai, Dong Dong Zhang
Abstract: nanohollow graphene oxide spheres have been successfully fabricated from graphene oxide nanosheets utilizing a water-in-oil emulsion technique. High quality graphene oxide nanosheets were prepared from natural flake graphite by oxidation and ultrasonic treatment. Graphene oxide nanosheets were supported by the water-in-oil interface, and self-assembled around water droplets under the assistance of ammonia. With the removal of aqueous ammonia, the graphene oxide nanosheets stacked and condensed at the water-in-oil interface and finally formed a shell structure around the soft template. The nanohollow graphene oxide spheres would be good candidates for catalyst supports, drug delivery and electrode materials in lithium-ion batteries.
540
Authors: Dong Lin Zhao, Xian Wei Zeng, Qi Sheng Xia, Jin Tian Tang
Abstract: The magnetite (Fe3O4) nanoparticles were prepared by coprecipitation of Fe3+ and Fe2+ with aqueous NaOH solution. The Fe3O4/polyaniline (PANI) magnetic composite nanoparticles with core-shell structure with diameter of 30-50 nm were prepared via an in-situ polymerization of aniline in aqueous solution containing Fe3O4 magnetic fluid. The inductive heat property of Fe3O4/polyaniline composite nanoparticles in an alternating current (AC) magnetic field was investigated. The potential of Fe3O4/polyaniline nanoparticles was evaluated for localized hyperthermia treatment of cancers. The saturation magnetization Ms and coercivity Hc of Fe3O4 nanoparticles are 50.05 emu/g and 137 Oe respectively, the Fe3O4/polyaniline composite nanoparticles, 26.34 emu/g and 0 Oe. Exposed in the alternating current (AC) magnetic field for 29 min, the temperatures of physiological saline suspension containing Fe3O4 nanoparticles or Fe3O4/polyaniline composite nanoparticles are 63.6 °C and 52.4 °C respectively. The Fe3O4/polyaniline composite nanoparticles would be useful as good thermoseeds for localized hyperthermia treatment of cancers.
1189
Authors: Dong Lin Zhao, Xia Li, Wei Dong Chi, Zeng Min Shen
Abstract: The filling of multi-walled carbon nanotubes (MWNTs) with metallic silver nanowires via wet chemistry method was investigated. The carbon nanotubes were filled with long continuous silver nanowires. The carbon nanotubes were almost opened and cut after being treated with concentrated nitric acid. Silver nitrate solution filled carbon nanotubes by capillarity. Carbon nanotubes were filled with silver nanowires after calcinations by hydrogen. The diameters of silver nanowires were in the range of 20-40nm, and lengths of 100nm-10μm. We studied the micromorphology of the silver nanowires filled in carbon nanotubes by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Based on the experimental results, a formation mechanism of the Ag nanowire-filled carbon nanotubes was proposed. And the microwave permittivity of the carbon nanotubes filled with metallic silver nanowires was measured in the frequency range from 2 GHz to 18 GHz. The loss tangent of the carbon nanotubes filled with metallic silver nanowires is high. So the carbon nanotubes filled with metallic silver nanowires would be a good candidate for microwave absorbent.
685
Authors: Shao Wu Ma, Dong Lin Zhao, Ning Na Yao, Li Xu
Abstract: The graphene/sulfur nanocomposite has been synthesized by heating a mixture of graphene sheets and elemental sulfur. The morphology, structure and electrochemical performance of graphene/sulfur nanocomposite as cathode material for lithium-sulfur batteries were systematically investigated by field-emission scanning electron microscope, X-ray diffraction and a variety of electrochemical testing techniques. The graphene/sulfur nanocomposite cathodes display a high reversible capacity of 800-1200 mAh g-1, and stable cycling for more than 100 deep cycles at 0.1 C. The graphene sheets have good conductivity and an extremely high surface area, and provide a robust electron transport network. The graphene network also accommodates the volume change of the electrode during the Li-S electrochemical reaction.
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