Publications (12)15.46 Total impact
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Dataset: Smith MA et al 2012 s001
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Dataset: Smith MA et al 2012 s002
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Dataset: Smith MA et al 2012 s003
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Article: Effect of synthesis temperature on the phase structure and electrochemical performance of nickel hydroxide
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ABSTRACT: Nickel hydroxide powder is prepared by chemical precipitation method, and the effect of synthesis temperature on the phase structure and electrochemical performances of nickel hydroxide is investigated. The phase structure is characterized by X-ray diffraction (XRD), and the electrochemical performances are characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge tests. The XRD results show that low temperatures (0–20°C) induce the precipitation of badly crystallized nickel hydroxide while at high temperatures (40–60°C) crystallized β-nickel hydroxide is formed. Electrochemical performance tests show that the nickel hydroxide synthesized at low temperature has better electrochemical reversibility, lower electrochemical reaction impedance, and higher discharge capacity than that of the nickel hydroxide synthesized at high temperature. KeywordsNickel hydroxide-Phase structure-Electrochemical performanceIonics 05/2012; 16(3):221-225. · 1.29 Impact Factor -
Article: Wolbachia and DNA Barcoding Insects: Patterns, Potential, and Problems
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ABSTRACT: Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When .2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region.PLoS ONE 05/2012; 7(5):e36514. doi:10.1371/journal.pone.0036514. · 4.09 Impact Factor -
Article: Wolbachia and DNA barcoding insects: patterns, potential, and problems.
[show abstract] [hide abstract]
ABSTRACT: Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein--wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor--which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region.PLoS ONE 01/2012; 7(5):e36514. · 4.09 Impact Factor -
Article: Theoretical Investigation on the Electron Transport Behavior of Fe-Porphyrin Complexes
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ABSTRACT: The electron transport behaviors of oxygen and carbon monoxide complexes of Fe-porphyrin (FeP) are investigated by nonequilibrium Green's function techniques combined with Density Functional Theory calculations. The results show that the molecular current of FeP decreases dramatically after adsorptions of oxygen and carbon monoxide. The molecular current decreases with a order of FeP > FeP+O2 complex > FeP+CO complex. This change of the molecular current after adsorption of oxygen or carbon monoxide can be potentially used to design a molecular sensor or a molecular switch.Integrated Ferroelectrics 01/2011; 127(1):91-96. · 0.30 Impact Factor -
Article: First principles study of the electron transport through cis-polyacetylene based molecular wires
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ABSTRACT: The electron transport properties of cis-polyacetylene and cis-polyacetylene based molecular wires (oligo(cyclopentadiene), oligo(pyrrole), and oligo(furan)) have been studied theoretically using a combination of density-functional theory and non-equilibrium Green′s functions method. The results demonstrate that the introduction of bridging group X (X=CH2, NH, and O) in cis-polyacetylene has a profound effect on the electron transport behavior of the molecules. The conductance of the four molecular wires decreases in the order of polyacetylene>oligo(cyclopentadiene)>oligo(furan)>oligo(pyrrole). In particular, the conductances of oligo(furan) and oligo(pyrrole) are much lower than those of polyacetylene and oligo(cyclopentadiene). The mechanism of this difference of electron transport properties of these four molecular systems is analyzed in terms of their geometric structures, electronic structures, transmission spectra, and spatial distribution of frontier orbitals. It is found that the energy levels of frontier molecular orbitals and the evolution of spatial distribution of frontier molecular orbitals with the applied bias are the essential reason for generating this difference of electron transport behaviors of the four molecular systems.Physica B Condensed Matter 406(20):3969-3974. · 1.06 Impact Factor -
Article: Synthesis and characterization of amorphous α-nickel hydroxide
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ABSTRACT: Amorphous α-nickel hydroxide was successfully synthesized by rapid freezing micro-emulsion precipitation method. The structure and property of the amorphous α-nickel hydroxide were characterized by XRD, TEM, IR, Raman spectra, and thermal gravimetric analysis. The results of the IR spectroscopy and thermal gravimetric analysis indicate that the amorphous α-nickel hydroxide contains water molecules and anions. Raman spectrum displays more peaks, indicating the highly disordered feature of the amorphous α-nickel hydroxide. Cyclic voltammogram and charge/discharge tests show that the amorphous α-nickel hydroxide in alkaline media has a relatively high discharge capacity (350 mAh g−1) and good structural stability, which indicates its potential application as an electrode material for secondary alkaline batteries.Journal of Alloys and Compounds 478:415-418. · 2.29 Impact Factor -
Article: Theoretical investigation on electron transport properties of a single molecular diode
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ABSTRACT: The nonequilibrium Green’s function (NEGF) approach in combination with density functional theory (DFT) was used to investigate the electron transport properties of a single diode molecule that consists of two weakly coupled electron donating π-system and electron withdrawing π-system, resembling the conventional p–n junctions. The results demonstrate rectification behavior of the diode molecule and the maximum rectification ratio is up to 7.7. The mechanism of the rectification behavior was analyzed in terms of the evolution of molecular energy levels, the change of spatial distribution of molecular orbitals, and the electron transmission spectra. The asymmetric evolutions of the energy levels and the alignment of the states localized on the electro donating and electron withdrawing segments with the applied voltage were found to be essential in generating this rectification behavior for the molecular system.Journal of Molecular Structure THEOCHEM 867:59-63. · 1.44 Impact Factor -
Article: Synthesis and characterization of the structural and electrochemical properties of Nd-Al codoped amorphous nickel hydroxide
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ABSTRACT: Nd-Al codoped amorphous nickel hydroxide powders were synthesized by microemulsion precipitation method combined with rapid freezing technique. The microstructure of the prepared samples was analyzed with X-ray diffractometer (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The electrochemical performances of the prepared samples were characterized with charge/discharge test, cyclic voltammetry, and electrochemical impedance spectra. The results showed that the codoping of Nd-Al resulted in more structural defects within the nickel hydroxide. Compared with the Al singly doped amorphous nickel hydroxide, the Nd-Al codoped amorphous nickel hydroxide showed improved electrochemical properties, such as better electrochemical reversibility, lower charge transfer resistance, and higher discharge capacity.Journal of Rare Earths 28(2):265-269. · 0.90 Impact Factor -
Article: Structure and electrochemical performance of nickel hydroxide synthesized by rapid quench method
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ABSTRACT: Nickel hydroxide with amorphous structure has been synthesized successfully by chemical precipitation method combined with rapid quench technique. The microstructure and morphology of the prepared samples were analyzed by XRD, Raman spectra, IR spectra, and SEM. The electrochemical performance of the sample was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge tests. The discharge capacity of the amorphous nickel hydroxide is 330.0 mAh g−1 at 0.2C, much higher than that of the theoretical capacity of β-nickel hydroxide (289.0 mAh g−1). Moreover, the amorphous nickel hydroxide exhibits higher electrochemical reaction reversibility, lower electrochemical impedance, and better cyclic stability compared with β-nickel hydroxide.Materials Research Bulletin. 45(12):2001-2005.
Top co-authors
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Institutions
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2012
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University of Guelph
- Department of Integrative Biology
Guelph, Ontario, Canada
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2011–2012
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Guilin University of Technology
Guilin, Guangxi Zhuangzu Zizhiqu, China
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