Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Amorphous ferric iron species (ferrihydrite or akaganeite of <5 nm in size) is the only known solid ferric iron oxide that can be reductively transformed by dissimilatory iron-reducing bacteria to magnetite completely. The lepidocrocite crystallite can be transformed into magnetite in the presence of abiotic Fe(II) at elevated pH or biogenic Fe(II) with particular growth conditions. The reduction of lepidocrocite by dissimilatory iron-reducing bacteria has been widely investigated showing varying results. Vali et al. (Proc Natl Acad Sci USA 101:16121-16126, 2004) captured a unique biologically mediated mineralization pathway where the amorphous hydrous ferric oxide transformed to lepidocrocite was followed by the complete reduction of lepidocrocite to single-domain magnetite. Here, we report the 57Fe Mössbauer hyperfine parameters of the time-course samples reported in Vali et al. (Proc Natl Acad Sci USA 101:16121-16126, 2004). Both the quadrupole splittings and linewidths of Fe(III) ions decrease consistently with the change of aqueous Fe(II) and transformations of mineral phases, showing the Fe(II)-mediated gradual regulation of the distorted coordination polyhedrons of Fe 3+ during the biomineralization process. The aqueous Fe(II) catalyzes the transformations of Fe(III) minerals but does not enter the mineral structures until the mineralization of magnetite. The simulated abiotic reaction between Fe(II) and lepidocrocite in pH-buffered, anaerobic media shows the simultaneous formation of green rust and its gradual transformation to magnetite plus a small fraction of goethite. We suggested that the dynamics of Fe(II) supply is a critical factor for the mineral transformation in the dissimilatory iron-reducing cultures. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

Experimental studies of the material properties of the forewing of cicada (Homóptera, Cicàdidae)

Detailed investigations on the structural and mechanical properties of the forewing of the cicada were carried out. Measurement of the structures of the wings showed that the thickness of the membrane of each cell and the diameter of each vein were non-uniform in both the longitudinal and transverse directions, and their means were approximately 12.2 and 133.3 μm, respectively. However, the aspect ratios of the wings and the bodies were quite uniform and were approximately equal to 2.98 and 2.13, respectively. Based on the measured thickness, mass and area of the membranes of the cells, the mean density and the mean area density of the wing were approximately 2.3 g cm -3 and 2.8×10 -3 g cm -2, respectively. In addition, the diameters of the veins of the wings, including the diameters of the holes in the vein of the leading edge, were examined. The mechanical properties of the wing were investigated separately by nanoindentation and tensile testing. The results indicated that the mean Young's modulus, hardness and yield stress of the membranes of the wings were approximately 3.7 GPa, 0.2 GPa and 29 MPa, respectively, and the mean Young's modulus and strength of the veins along the direction of the venation of wings were approximately 1.9 GPa and 52 MPa, respectively. Finally, the relevant results were briefly analyzed and discussed, providing a guideline to the biomimetic design of the aerofoil materials of micro air vehicles.published_or_final_versio

A Novel NFC Antenna for Metal Cover Smartphone Applications

© 2018 IEEE. A miniaturized dual-loop near field communication antenna of size 15 mm×25 mm is proposed for metal cover smartphone applications. By embedded it with a small rectangular slot of size 8 mm×16 mm loaded metal cover, the direction of the eddy current induced on metal cover will be the same with the current flow the on the dual loop NFC antenna coil. It's worth noting that the proposed NFC antenna design was certified by the Europay, Mastercard and Visa (EMV) test

An experimental study on self-powered vibration control and monitoring system using electromagnetic TMD and wireless sensors

Author name used in this manuscript: You-lin Xu2011-2012 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Linear electromagnetic devices for vibration damping and energy harvesting : modeling and testing

Author name used in this manuscript: You-lin Xu2011-2012 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Multi-type sensor placement and data fusion for structural monitoring: numerical simulation

Author name used in this publication: S. ZhuVersion of RecordPublishe

Strain Softening Induced by High Pressure Torsion in Copper Alloys

Three kinds of Cu-Al alloys and a pure Cu sample with different stacking fault energies (SFEs) are deformed using room temperature rolling (RR) and high pressure torsion (HPT), respectively. The microstructure is analysed by means of transaction electron microscopy and X-ray diffraction. It is found that HIPT is more feasible to obtain nanocrystals and profuse twins. Tailoring the SFE can promote sample strength without sacrificing the ductility of the Cu alloys. The tensile properties of samples processed by HPT and RR are compared. It is discovered that the HPT process leads to the strain softening phenomenon in samples with relatively high SFE. The excellent mechanical properties can be obtained in samples deformed by HPT with a SFE of 6 mJ/m(2), in which strain softening was restrained and strain hardening played a dominant role in the deformation process. The relationship between tensile properties and microstructures of the deformed metals is also investigated.110Ysciescopu

2.5D large eddy simulation of vertical axis wind turbine in consideration of high angle of attack flow

Author name used in this manuscript: You-lin Xu2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Displacement-based design approach for highway bridges with SMA isolators

Author name used in this manuscript: You-lin Xu2011-2012 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe