Yuedong Meng
Chinese Academy of Sciences
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Publication
Featured researches published by Yuedong Meng.
Journal of Physical Chemistry B | 2009
Dadong Shao; Zhongqing Jiang; Xiangke Wang; Jiaxing Li; Yuedong Meng
Carboxymethyl cellulose (CMC) is grafted on multiwalled carbon nanotubes (MWCNT) by using plasma techniques. The CMC grafted MWCNT (MWCNT-g-CMC) is characterized by using Fourier transform infrared spectra (FT-IR), Raman spectra, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA)-differential thermal analysis (DTA), scanning electron microscopy (SEM), and N(2)-BET methods in detail. The application of MWCNT-g-CMC in the removal of UO(2)(2+) from aqueous solution is investigated. MWCNT-g-CMC has much higher sorption ability in the removal of UO(2)(2+) than raw MWCNT. The MWCNT-g-CMC is a suitable material in the preconcentration and solidification of heavy metal ions from large volume of aqueous solutions.
Journal of Materials Chemistry | 2009
Zhongqing Jiang; Xingyao Yu; Zhong-Jie Jiang; Yuedong Meng; Yicai Shi
Plasma-treated multi-walled carbon nanotubes (MWCNTs) have been used as a substrate for the deposition of Pt nanoparticles. These Pt nanoparticles deposited on MWCNTs showed a higher catalytic activity in a methanol electro-oxidation reaction even with a lower amount of precious metal catalyst used. The higher catalytic activity is attributed to less damage of the carbon nanotubes during plasma treatment. It also shows that direct contact between metal nanoparticles and carbon nanotubes can improve the performance of composites.
Journal of Physical Chemistry B | 2011
Di B; Yuedong Meng; Yao Wang; X. J. Liu; Zhisheng An
Combining the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model and the extended Hubbard model (EHM), we analyze the scattering and combination in conjugated polymers of two polarons with the same charges and parallel or antiparallel spins using a nonadiabatic evolution method. Results show that collisions between the two same charge polarons with parallel spin are essentially elastic due to strong Pauli repulsion, whereas the two same charge polarons with antiparallel spins can combine into a singlet bipolaronic state. The dynamics of bipolarons on two coupled polymer chains and at the interface of a polymer/polymer heterojunction are discussed in detail. This knowledge will serve to understand the dynamics of the system when many polarons are created in the system, e.g., by electroluminescence.
Physics of Plasmas | 2010
L. Chen; Peng Zhao; Xingsheng Shu; Jie Shen; Yuedong Meng
For the purpose of unveiling the parameters influencing the length of atmospheric pressure plasma plume, an over 165 cm long argon plasma plume is generated in the quartz tube attached to the nozzle of the device. Dependence of plasma length on discharge parameters such as applied voltage, frequency of power supply, and argon gas flow rate was investigated. Experimental results indicated that (a) the applied voltage plays crucial roles on plasma plume length, that is, the plasma plume length exponentially increases with the applied voltage, (b) the plasma plume length increases with frequency, more obviously when the applied voltage is higher, (c) the plasma plume length increases with argon gas flow rate, reaches its maximum at critical value of the gas flow rate, and then decreases again. An evaluation of the physical phenomena involved in streamer propagation, particularly of the energy balance, was investigated. The numerical results were qualitatively consistent with previous experimental results by ...
Applied Physics Express | 2012
Jie Shen; Cheng Cheng; Shidong Fang; Hongbing Xie; Yan Lan; Yuedong Meng; Jiarong Luo; Xiangke Wang
To determine an efficient sterilization mechanism, Bacillus subtilis spore samples were exposed to an atmospheric plasma jet. By using argon/oxygen mixture gas, the decimal reduction value was reduced from 60 s (using argon gas) to 10 s. More dramatically, after 5 min treatment, the colony-forming unit (CFU) was reduced by six orders. To understand the underlying mechanism of the efficient sterilization by plasma, the contributions from heat, UV radiation, charged particles, ozone, and reactive oxygen radicals were distinguished in this work, showing that charged particles and ozone were the main killing factors. The shape changes of the spores were also discussed.
Journal of Applied Physics | 2013
P. Zhao; W. Zheng; Yuedong Meng; Masaaki Nagatsu
With a view to fabricating future flexible electronic devices, an atmospheric-pressure plasma jet driven by 13.56 MHz radio-frequency power is developed for depositing Cu thin films on polyimide, where a Cu wire inserted inside the quartz tube was used as the evaporation source. A polyimide substrate is placed on a water-cooled copper heat sink to prevent it from being thermally damaged. With the aim of preventing oxidation of the deposited Cu film, we investigated the effect of adding H2 to Ar plasma on film characteristics. Theoretical fitting of the OH emission line in OES spectrum revealed that adding H2 gas significantly increased the rotational temperature roughly from 800 to 1500 K. The LMM Auger spectroscopy analysis revealed that higher-purity Cu films were synthesized on polyimide by adding hydrogen gas. A possible explanation for the enhancement in the Cu film deposition rate and improvement of purity of Cu films by H2 gas addition is that atomic hydrogen produced by the plasma plays important ...
Journal of Applied Physics | 2014
Dezhi Xiao; Cheng Cheng; Jie Shen; Yan Lan; Hongbing Xie; Xingsheng Shu; Yuedong Meng; Jiangang Li; Paul K. Chu
An atmospheric-pressure non-thermal plasma jet driven by high frequency alternating current and operating on N2 and N2/O2 gas mixture is investigated. The plasma jet can reach 55 mm in length at a gas flow rate of 2500 l/h. The gas temperature at a distance of 4 mm from the nozzle is close to room temperature. Optical emission spectroscopy is employed to investigate the important plasma parameters such as the excited species, rotational temperature, vibrational temperature, and excitation temperature under different discharge conditions. The results show that the plasma source operates under non-equilibrium conditions. The absolute irradiance intensity of the vibrational band N2(C-B) in the active region is measured. Taking into account the irradiance intensity of N2(C-B,0-0) and N2(B-X,0-0) as well as measured current, the electron density, which is determined by considering direct and step-wise electron impact excitation of nitrogen emission, reaches a maximum value of 5.6 × 1020/m3.
Journal of Physical Chemistry B | 2011
Di B; Yuedong Meng; Yao Wang; X. J. Liu; Zhisheng An
Combining the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model and the extended Hubbard model (EHM), the scattering and combination of oppositely charged bipolarons in conjugated polymers are investigated using a nonadiabatic evolution method. On the basis of this physical picture, bipolarons can scatter into a singlet biexcitonic state, in which two electrons and two holes are trapped together by a lattice distortion. This biexcitonic state can emit one photon to an exciton state, which can subsequently decay to the ground state. The results indicate that the scattering and combination of oppositely charged bipolarons may provide guidance for improving the internal quantum efficiency for electroluminescence to as high as 75% in polymer light-emitting diodes.
Journal of Hazardous Materials | 2010
Peng Zhao; Yiman Jiang; L. Chen; Mingzhou Chen; Yuedong Meng
Due to the toxicity of dioxins, furans and heavy metals, there is a growing environmental concern on municipal solid waste incinerator (MSWI) fly ash in China. The purpose of this study is directed towards the volume-reduction of fly ash without any additive by thermal plasma and recycling of vitrified slag. This process uses extremely high-temperature in an oxygen-starved environment to completely decompose complex waste into very simple molecules. For developing the proper plasma processes to treat MSWI fly ash, a new crucible-type plasma furnace was built. The melting process metamorphosed fly ash to granulated slag that was less than 1/3 of the volume of the fly ash, and about 64% of the weight of the fly ash. The safety of the vitrified slag was tested. The properties of the slag were affected by the differences in the cooling methods. Water-cooled and composite-cooled slag showed more excellent resistance against the leaching of heavy metals and can be utilized as building material without toxicity problems.
Surface Review and Letters | 2009
Zhongqing Jiang; Yuedong Meng; Zhong-Jie Jiang; Yicai Shi
Sulfonated ultra-thin proton-exchange polymer membrane carrying pyridine groups was made from a plasma polymerization of styrene, 2-vinylpyridine, and trifluoromethanesulfonic acid by after-glow capacitively coupled discharge technique. Pyridine groups tethered to the polymer backbone acts as a medium through the basic nitrogen for transfer of protons between the sulfonic acid groups of proton exchange membrane. It shows that the method using present technology could effectively depress the degradation of monomers during the plasma polymerization. Spectroscopic analyses reveal that the obtained membranes are highly functionalized with proton exchange groups and have higher proton conductivity. Thus, the membranes are expected to be used in direct methanol fuel cells.