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Aming Xie - One of the best experts on this subject based on the ideXlab platform.

Rui Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Ultralight polymer-derived ceramic aerogels with wide bandwidth and effective Electromagnetic Absorption properties
    Journal of the European Ceramic Society, 2017
    Co-Authors: Wanyu Zhao, Biao Zhao, Gang Shao, Mingjie Jiang, Hailong Wang, Deliang Chen, Rui Zhang
    Abstract:

    Abstract In this work, ultralight polymer-derived ceramic aerogels (PDCA) were prepared by a facile method of hydrosilylation crosslink and freeze drying. The Electromagnetic Absorption properties of ultralight PDCA were investigated for the first time. The PDCA pyrolyzed at 1000 °C shows a uniform three-dimensional (3D) framework with a low bulk density of ∼0.19 g/cm 3 and high surface area of 134.48 m 2 /g. The Electromagnetic properties of PDCA were characterized by a vector network analyzer. The minimum reflection and Absorption bandwidth of PDCA pyrolyzed at 1000 °C, 1200 °C and 1400 °C are −43.37 dB @ 7.6 GHz, −42.01 dB@12.5 GHz, and −31.69 dB@17.3 GHz and 3.8 GHz, 6.6 GHz and 4.2 GHz, respectively, at the frequency range of 2–18 GHz. The strong Electromagnetic Absorption and wide bandwidth features of PDCA could be attributed to the multiple reflections of microwaves in the 3D framework, as well as the high dielectric loss and proper conductivity.

  • in situ synthesis of novel urchin like zns ni3s2 ni composite with a core shell structure for efficient Electromagnetic Absorption
    Journal of Materials Chemistry C, 2015
    Co-Authors: Biao Zhao, Wanyu Zhao, Gang Shao, Bingbing Fan, Rui Zhang, Shihao Zhang, Keke Guan
    Abstract:

    A novel urchin-like ZnS/Ni3S2@Ni composite with a core–shell structure was successfully synthesized by a facile two-stage method. The structure and morphology were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectrometry. The influence of reaction temperature on the structure and morphology of the ZnS/Ni3S2@Ni products was investigated by the aid of XRD and SEM techniques. A plausible formation mechanism for the core–shell urchin-like architectures was proposed based on temperature dependent experiments. Electromagnetic Absorption measurements show that the urchin-like ZnS/Ni3S2@Ni composite possesses outstanding Electromagnetic Absorption properties compared with other ZnS/Ni3S2@Ni composites. The optimal reflection loss of −27.6 dB can be observed at 5.2 GHz and the effective Absorption (below −10 dB, 90% Electromagnetic Absorption) bandwidth is 2.5 GHz (12.2–14.7 GHz) with a thickness of only 1.0 mm. The location of the minimum reflection loss can be tuned between 4.6 GHz and 18.0 GHz for the absorber by tuning the thickness between 0.8–2.5 mm. The enhanced Electromagnetic Absorption properties were attributed to a synergistic effect between dielectric loss and magnetic loss, multiple interfacial polarization resulting from the heterogeneous structure of the core–shell ternary ZnS/Ni3S2@Ni composite, good impedance matching and a unique urchin-like structure.

  • Corrosive synthesis and enhanced Electromagnetic Absorption properties of hollow porous Ni/SnO2 hybrids.
    Dalton transactions (Cambridge England : 2003), 2015
    Co-Authors: Biao Zhao, Wanyu Zhao, Gang Shao, Bingbing Fan, Rui Zhang
    Abstract:

    In this study, novel porous hollow Ni/SnO2 hybrids were prepared by a facile and flexible two-step approach composed of solution reduction and subsequent reaction-induced acid corrosion. In our protocol, it can be found that the hydrothermal temperature exerts a vital influence on the phase crystal and morphology of Ni/SnO2 hybrids. Notably, the Ni microspheres might be completely corroded in the hydrothermal process at 220 °C. The complex permittivity and permeability of Ni/SnO2 hybrids–paraffin wax composite were measured based on a vector network analyzer in the frequency range of 1–18 GHz. Electromagnetic Absorption properties of samples were evaluated by transmission line theory. Ni/SnO2 hybrid composites exhibit superior Electromagnetic Absorption properties in comparison with pristine Ni microspheres. The outstanding Electromagnetic Absorption performances can be observed for the hollow porous Ni/SnO2 hybrid prepared at 200 °C. The minimum reflection loss is −36.7 dB at 12.3 GHz, and the effective Electromagnetic wave Absorption band (RL < −10 dB, 90% microwave attenuation) was in the frequency range of 10.6–14.0 GHz with a thin thickness of 1.7 mm. Excellent Electromagnetic Absorption properties were assigned to the improved impedance match, more interfacial polarization and unique hollow porous structures, which can result in microwave multi-reflection and scattering. This novel hollow porous hybrid is an attractive candidate for new types of high performance Electromagnetic wave-absorbing materials, which satisfies the current requirements of Electromagnetic absorbing materials, which include wide-band Absorption, high-efficiency Absorption capability, thin thickness and light weight.

  • In situ synthesis of novel urchin-like ZnS/Ni3S2@Ni composite with a core–shell structure for efficient Electromagnetic Absorption
    Journal of Materials Chemistry C, 2015
    Co-Authors: Biao Zhao, Wanyu Zhao, Gang Shao, Bingbing Fan, Zhang Shihao, Guan Keke, Rui Zhang
    Abstract:

    A novel urchin-like ZnS/Ni3S2@Ni composite with a core–shell structure was successfully synthesized by a facile two-stage method. The structure and morphology were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectrometry. The influence of reaction temperature on the structure and morphology of the ZnS/Ni3S2@Ni products was investigated by the aid of XRD and SEM techniques. A plausible formation mechanism for the core–shell urchin-like architectures was proposed based on temperature dependent experiments. Electromagnetic Absorption measurements show that the urchin-like ZnS/Ni3S2@Ni composite possesses outstanding Electromagnetic Absorption properties compared with other ZnS/Ni3S2@Ni composites. The optimal reflection loss of −27.6 dB can be observed at 5.2 GHz and the effective Absorption (below −10 dB, 90% Electromagnetic Absorption) bandwidth is 2.5 GHz (12.2–14.7 GHz) with a thickness of only 1.0 mm. The location of the minimum reflection loss can be tuned between 4.6 GHz and 18.0 GHz for the absorber by tuning the thickness between 0.8–2.5 mm. The enhanced Electromagnetic Absorption properties were attributed to a synergistic effect between dielectric loss and magnetic loss, multiple interfacial polarization resulting from the heterogeneous structure of the core–shell ternary ZnS/Ni3S2@Ni composite, good impedance matching and a unique urchin-like structure.

Mingyang Wang - One of the best experts on this subject based on the ideXlab platform.

Haiqian Zhang - One of the best experts on this subject based on the ideXlab platform.

  • coxfey c composites with tunable atomic ratios for excellent Electromagnetic Absorption properties
    Scientific Reports, 2015
    Co-Authors: Hualiang Lv, Guangbin Ji, Haiqian Zhang, Meng Li, Yue Zhao, Baoshan Zhang, Dongming Tang, Youwei Du
    Abstract:

    The shell on the nano-magnetic absorber can prevent oxidation, which is very important for its practical utilization. Generally, the nonmagnetic shell will decrease the integral magnetic loss and thus weaken the Electromagnetic Absorption. However, maintaining the original Absorption properties of the magnetic core is a major challenge. Here, we designed novel and facile CoxFey@C composites by reducing CoxFe3−xO4@phenolic resin (x = 1, 0.5 and 0.25). High saturation magnetization value (Ms) of CoxFey particle, as a core, shows the interesting magnetic loss ability. Meanwhile, the carbon shell may increase the integral dielectric loss. The resulting composite shows excellent Electromagnetic Absorption properties. For example, at a coating thickness of 2 mm, the RLmin value can reach to −23 dB with an effective frequency range of 7 GHz (11–18 GHz). The mechanisms of the improved microwave Absorption properties are discussed.

  • CoxFey@C Composites with Tunable Atomic Ratios for Excellent Electromagnetic Absorption Properties
    Scientific reports, 2015
    Co-Authors: Haiqian Zhang, Yue Zhao, Baoshan Zhang, Zhongzheng Zuo, Dongming Tang
    Abstract:

    The shell on the nano-magnetic absorber can prevent oxidation, which is very important for its practical utilization. Generally, the nonmagnetic shell will decrease the integral magnetic loss and thus weaken the Electromagnetic Absorption. However, maintaining the original Absorption properties of the magnetic core is a major challenge. Here, we designed novel and facile CoxFey@C composites by reducing CoxFe3−xO4@phenolic resin (x = 1, 0.5 and 0.25). High saturation magnetization value (Ms) of CoxFey particle, as a core, shows the interesting magnetic loss ability. Meanwhile, the carbon shell may increase the integral dielectric loss. The resulting composite shows excellent Electromagnetic Absorption properties. For example, at a coating thickness of 2 mm, the RLmin value can reach to −23 dB with an effective frequency range of 7 GHz (11–18 GHz). The mechanisms of the improved microwave Absorption properties are discussed.

  • a novel rod like mno2 fe loading on graphene giving excellent Electromagnetic Absorption properties
    Journal of Materials Chemistry C, 2015
    Co-Authors: Xiaohui Liang, Haiqian Zhang
    Abstract:

    Impedance matching and the attenuation constant, α, are two key parameters in determining Electromagnetic Absorption properties. Although materials with single magnetic or dielectric loss properties have a high α value, they nonetheless suffer from poor impedance matching. The design of magnetic and dielectric composites might possibly be an effective method of solving this problem, but unfortunately the introduction of magnetic material may give a poor value of α. In order to obtain absorptive materials with high impedance matching and a high value of α, we have designed a novel ternary composite of MnO2@Fe–graphene. A 30 nm wide rod-like strip of MnO2 was first obtained by a simple liquid process. Liquid decomposition of Fe(CO)5 was then carried out to deposit iron on the surface of the rod-like structure, and the MnO2@Fe was finally loaded on graphene by a liquid deposition technique. The resulting ternary composite exhibited attractive Electromagnetic Absorption properties, in which the optimal reflection loss of up to −17.5 dB obtained with a thin coating thickness of 1.5 mm was able to satisfy the requirements of lightness of weight and a high degree of Absorption. The effective bandwidth frequency of MnO2@Fe–GNS is broader than that of pure MnO2 or MnO2@Fe, possibly due to its moderate impedance matching and attenuation ability. The possible attenuation mechanism will also be discussed.

  • Porous Three-Dimensional Flower-like Co/CoO and Its Excellent Electromagnetic Absorption Properties
    ACS applied materials & interfaces, 2015
    Co-Authors: Xiaohui Liang, Haiqian Zhang
    Abstract:

    The porous three-dimensional (3-D) flower structures assembled by numerous ultrathin flakes were favor for strengthen Electromagnetic Absorption capability. However, it still remains a big challenge to fabricate such kind of materials. In this study, an easy and flexible two-step method consisting of hydrothermal and subsequent annealing process have been developed to synthesize the porous 3-D flower-like Co/CoO. Interestingly, we found that the suitable heat treatment temperature played a vital role on the flower-like structure, composition, and Electromagnetic Absorption properties. In detail, only in the composite treated with 400 °C can we gain the porous 3-D flower structure. If the annealing temperature were heated to 300 °C, the Co element was unable to generate. Moreover, when the annealing temperature increased from 400 to 500 °C, these flower-like structures were unable to be kept because the enlarged porous diameter would wreck the flower frame. Moreover, these 3-D porous flower-like structures...

  • A novel rod-like MnO2@Fe loading on graphene giving excellent Electromagnetic Absorption properties
    Journal of Materials Chemistry C, 2015
    Co-Authors: Xiaohui Liang, Haiqian Zhang
    Abstract:

    Impedance matching and the attenuation constant, α, are two key parameters in determining Electromagnetic Absorption properties. Although materials with single magnetic or dielectric loss properties have a high α value, they nonetheless suffer from poor impedance matching. The design of magnetic and dielectric composites might possibly be an effective method of solving this problem, but unfortunately the introduction of magnetic material may give a poor value of α. In order to obtain absorptive materials with high impedance matching and a high value of α, we have designed a novel ternary composite of MnO2@Fe–graphene. A 30 nm wide rod-like strip of MnO2 was first obtained by a simple liquid process. Liquid decomposition of Fe(CO)5 was then carried out to deposit iron on the surface of the rod-like structure, and the MnO2@Fe was finally loaded on graphene by a liquid deposition technique. The resulting ternary composite exhibited attractive Electromagnetic Absorption properties, in which the optimal reflection loss of up to −17.5 dB obtained with a thin coating thickness of 1.5 mm was able to satisfy the requirements of lightness of weight and a high degree of Absorption. The effective bandwidth frequency of MnO2@Fe–GNS is broader than that of pure MnO2 or MnO2@Fe, possibly due to its moderate impedance matching and attenuation ability. The possible attenuation mechanism will also be discussed.

Mengxiao Sun - One of the best experts on this subject based on the ideXlab platform.