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Articles 31 - 60 of 163
Full-Text Articles in Engineering
Laboratory Evaluation Of Smear Zone And Correlation Between Permeability And Moisture Content, I. Sathananthan, B. Indraratna
Laboratory Evaluation Of Smear Zone And Correlation Between Permeability And Moisture Content, I. Sathananthan, B. Indraratna
Faculty of Engineering - Papers (Archive)
In this study, the extent of the smear zone and the reduction of permeability and water content within the smear zone were investigated using a large-scale consolidometer. The installation of vertical drains by means of a mandrel causes significant disturbance of the subsoil surrounding the mandrel, resulting in a smear zone. The extent of the smear zone for Moruya clay New South Wales, Australia was estimated on the basis of normalized permeability and the reduction of water content by taking undisturbed samples horizontally and vertically at different locations. This study reveals that a significant reduction in water content and horizontal …
Shot Noise And Conductance In Metallic Carbon Nanotubes In The Presence Of Correlated Defects, Q. Zhang, H. Yang, C. Zhang, Z. Ma
Shot Noise And Conductance In Metallic Carbon Nanotubes In The Presence Of Correlated Defects, Q. Zhang, H. Yang, C. Zhang, Z. Ma
Faculty of Engineering - Papers (Archive)
We investigate the effect of isolated scattering centers on the electronic transport in metallic carbon nanotubes. It is found that the impurity potential significantly alters the overlap of electronic wave functions and results in a rapid oscillation in the conductance and the shot noise. Furthermore, the conductance and the shot noise near the neutral Fermi energy depend periodically on the relative position of the scatterers and on the phase factor ϕ which is generated by the scattering. If two defects are in the same sublattice and Δd≫ac, the conductance near the neutral Fermi energy is dropped to G …
Electro-Oxidation Of Ethanol On Pt-Wo3/C Electrocatalyst, D. Y. Zhang, Z. F. Ma, G. X. Wang, Konstantin Konstantinov, X. X. Yuan, Hua-Kun Liu
Electro-Oxidation Of Ethanol On Pt-Wo3/C Electrocatalyst, D. Y. Zhang, Z. F. Ma, G. X. Wang, Konstantin Konstantinov, X. X. Yuan, Hua-Kun Liu
Faculty of Engineering - Papers (Archive)
Ptx-WO3/C electrocatalysts were prepared by microwave colloid-reduction method. Transmission electron microscopy examination showed uniform dispersion of platinum with particle sizes less than 5 nm. Structures of the Ptx-WO3/C electrocatalysts were characterized by X-ray diffraction and energy dispersive spectroscopy, the electrochemical characteristics and electro-oxidation of electro-oxidation of ethanol on the Ptx-WO3/C electrocatalysts were also studied by cyclic voltammetry, linear sweep, and chronoamperometry. The results show that the Ptx-WO3/C electrocatalysts have higher catalytic activity to ethanol electrooxidation than the commercial Pt/C catalysts; perhaps caused by the “hydrogen spill-over effect.” The reaction mechanisms of the ethanol electro-oxidation on the Ptx-WO3/C were inferred according …
Metastable Behavior Of Vortex Matter In The Electronic Transport Processes Of Homogenous Superconductors, X. B. Xu, Y. Liu, H. Fangohr, L. Zhang, Shichao Ding, Z. H. Wang, S. L. Liu, G. J. Wu, H. M. Shao
Metastable Behavior Of Vortex Matter In The Electronic Transport Processes Of Homogenous Superconductors, X. B. Xu, Y. Liu, H. Fangohr, L. Zhang, Shichao Ding, Z. H. Wang, S. L. Liu, G. J. Wu, H. M. Shao
Faculty of Engineering - Papers (Archive)
We study numerically the effect of vortex pinning on the hysteresis voltage-temperature (V-T) loop of vortex matter. It is found that different types of the V-T loops result from different densities of vortex pinning center. An anticlockwise V-T loop is observed for the vortex system with dense pinning centers, whereas a clockwise V-T loop is brought about for vortices with dilute pinning centers. It is shown that the size of the V-T loop becomes smaller for lower experimental speed, higher magnetic field, or weak pinning strength. Our numerical observation is in good agreement with experiments.
Optical Absorption Coefficients In Two-Dimensional Semiconductors Under Strong Magnetic Field, L. Y. Yu, J. C. Cao, C. Zhang
Optical Absorption Coefficients In Two-Dimensional Semiconductors Under Strong Magnetic Field, L. Y. Yu, J. C. Cao, C. Zhang
Faculty of Engineering - Papers (Archive)
We calculate the photon absorption coefficient of hot two-dimensional electrons in the presence of a strong magnetic field. The electrons interact strongly with the optical phonons and the acoustic phonons in quantum wells. The dependence of the optical absorption on the magnetic field is obtained by using the quantum mechanical kinetic theory. It is found that the photon absorption spectrum displays a local magnetophonon resonance. The magnetophonon absorption resulting from inelastic scattering between Landau levels is more pronounced at higher temperature. The effect of subband nonparabolicity on the absorption coefficient is also discussed.
Chandra Observations Of Gas Stripping In The Elliptical Galaxy Ngc 4552 In The Virgo Cluster, M. Machacek, C. Jones, W. R. Forman, P. Nulsen
Chandra Observations Of Gas Stripping In The Elliptical Galaxy Ngc 4552 In The Virgo Cluster, M. Machacek, C. Jones, W. R. Forman, P. Nulsen
Faculty of Engineering - Papers (Archive)
We use a 54.4 ks Chandra observation to study ram pressure stripping in NGC 4552 (M89), an elliptical galaxy in the Virgo Cluster. Chandra images in the 0.5–2 keV band show a sharp leading edge in the surface brightness 3.1 kpc north of the galaxy center, a cool (kT = 0.51 keV) tail with mean density ne ∼ (5.4±1.7) × 10-3 cm-3 extending ∼10 kpc to the south of the galaxy, and two 3–4 kpc horns of emission extending southward away from the leading edge. These are all features characteristic of supersonic ram pressure stripping of galaxy …
Acid Sulphate Soil Remediation Techniques On The Shoalhaven River Floodplain, Australia, Buddhima Indraratna, A. N. Golab, W. Glamore, B. Blunden
Acid Sulphate Soil Remediation Techniques On The Shoalhaven River Floodplain, Australia, Buddhima Indraratna, A. N. Golab, W. Glamore, B. Blunden
Faculty of Engineering - Papers (Archive)
A commonly used flood mitigation technique in coastal areas of Australia during the late 1960’s was the installation of one-way floodgates on flood mitigation drains. In regions affected by acid sulphate soils (the oxidation of pyrite in the soil forms sulphuric acid), the floodgates prevent tidal carbonate/bicarbonate buffering of the drains and thereby create reservoirs of acidic water (pH < 4.5) that discharge during low tide. Several acid sulphate soil remediation techniques have been used in coastal lowland in southeastern NSW, Australia. Following extensive monitoring and finite element modelling of groundwater conditions and quality, fixed level v-notch weirs were installed at three elevations to maintain elevated groundwater levels. The weirs successfully maintained the groundwater level above the acid sulphate soils, preventing additional pyrite oxidation, and reduced the rate of discharge of acid to the drain. Following further monitoring, investigation into anaerobic acid sources, and finite element based geochemical modelling, modified two-way floodgates that allow tidal ingress were installed. The modified floodgates were successful in buffering the drain water pH before discharging the drain water into adjacent waterways. Numerical analysis based on FEM was extended to illustrate that saline intrusion into the surrounding soil (as a result of tidal ingress and acid buffering in the drains) was not a major concern for the pastureland or other agricultural activities
Three-Dimensional Analysis Of Soft Soil Consolidation Improved By Prefabricated Vertical Drains, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Three-Dimensional Analysis Of Soft Soil Consolidation Improved By Prefabricated Vertical Drains, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Faculty of Engineering - Papers (Archive)
A system of prefabricated vertical drains (PVDs) with a surcharge load is an effective method for accelerating soil consolidation by promoting radial flow. This study presents a three-dimensional (3D) finite element model for soft soil improved by a single drain. In the finite element analysis, the actual rectangular PVD cross-section is considered, and the equivalent drain diameter is then back calculated based on the consolidation curves. The numerical predictions are then compared to previous studies. The settlements observed in the laboratory are subsequently compared with the three-dimensional finite element analysis incorporating the modified Cam-Clay model and Hansbo’s theory.
Stabilisation Of Ballasted Rail Tracks And Underlying Soft Formation Soils With Geosynthetic Grids And Drains, Buddhima Indraratna, Mohamed A. Shahin, Cholachat Rujikiatkamjorn, David Christie
Stabilisation Of Ballasted Rail Tracks And Underlying Soft Formation Soils With Geosynthetic Grids And Drains, Buddhima Indraratna, Mohamed A. Shahin, Cholachat Rujikiatkamjorn, David Christie
Faculty of Engineering - Papers (Archive)
Railway ballast deforms and degrades progressively under heavy cyclic loading. Ballast degradation is influenced by several factors including the amplitude and number of load cycles, gradation of aggregates, track confining pressure, angularity and fracture strength of individual grains. The degraded ballast is usually cleaned on track, otherwise, fully or partially replaced by fresh ballast, depending on the track settlement and current density. The use of composite geosynthetics at the bottom of recycled ballast layer is highly desirable to serve the functions of both drainage and separation of ballast from subballast. Construction of the rail track also requires appropriate improvement of …
Second Order Nonlinear Inelastic Analysis Of Composite Steel–Concrete Members. Ii: Applications, Y. L. Pi, M. A. Bradford, B. Uy
Second Order Nonlinear Inelastic Analysis Of Composite Steel–Concrete Members. Ii: Applications, Y. L. Pi, M. A. Bradford, B. Uy
Faculty of Engineering - Papers (Archive)
In the companion paper, a total Lagrangian finite element (FE) model was formulated for the second order nonlinear inelastic analysis of steel–concrete composite members. This paper describes the implementation of the incremental–iterative procedure for the FE model. It has been found that using the standard tangent modulus matrix in an incremental–iterative solution procedure may cause error accumulations. These errors in turn lead to an unsafe drift from the yield surfaces, and the yield criteria may be violated. Consequently, the quadratic asymptotic rate of convergence of the Newton–Raphson method is lost. To solve this problem, a consistent tangent modulus matrix is …
Two Colour Plasmon Excitation In An Electron-Hole Bilayer Structure Controlled By The Spin-Orbit Interaction, C. H. Yang, A. Wright, Feng Gao, C. Zhang, Z. Zeng, W. Xu
Two Colour Plasmon Excitation In An Electron-Hole Bilayer Structure Controlled By The Spin-Orbit Interaction, C. H. Yang, A. Wright, Feng Gao, C. Zhang, Z. Zeng, W. Xu
Faculty of Engineering - Papers (Archive)
In recent years, the terahertz plasma effects in high-mobility electronic systems have attracted much attention theoretically and experimentally. Plasma excitation in the terahertz regime can be used for generation, detection, and frequency multiplication of terahertz radiation. A channel of a field-effect transistor with sufficiently high electron mobility can serve as a resonant cavity for the plasma oscillation. When the signal period is in the vicinity of the electron transit time, self-excitation of plasma oscillation can occur. If the typical plasma frequency is in the terahertz regime, the phenomenon can be used as a terahertz source.
Selection Of Potential Reactive Materials For A Permeable Reactive Barrier For Remediating Acidic Groundwater In Acid Sulphate Soil Terrains, A. N. Golab, M. A. Peterson, Buddhima Indraratna
Selection Of Potential Reactive Materials For A Permeable Reactive Barrier For Remediating Acidic Groundwater In Acid Sulphate Soil Terrains, A. N. Golab, M. A. Peterson, Buddhima Indraratna
Faculty of Engineering - Papers (Archive)
A permeable reactive barrier is being designed to remediate leachate from acid sulphate soils. The current research relates to testing of alkaline materials for use in the barrier, with an emphasis on waste materials. Thirteen alkaline materials including recycled concrete, limestone, calcite-bearing zeolitic breccia, blast furnace slag, lime and fly ash were tested. The batch tests involved several phases, such as leaching in deionised water to characterise the soluble components of the materials and the pH that each material could achieve. Another phase involved testing with acidic water (pH 3) to determine the acid leachable components of the materials and …
Electrochemical Performance Of Co3o4–C Composite Anode Materials, Scott A. Needham, G. X. Wang, Konstantin Konstantinov, Y. Tournayre, Z. Lao, Hua-Kun Liu
Electrochemical Performance Of Co3o4–C Composite Anode Materials, Scott A. Needham, G. X. Wang, Konstantin Konstantinov, Y. Tournayre, Z. Lao, Hua-Kun Liu
Faculty of Engineering - Papers (Archive)
Co3O4–C composite powder has been synthesized via spray pyrolysis of cobalt nitrate-sugar solution at 600°C and assessed for application as anode materials in Li-ion batteries. Microstructural characterization by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirm an even distribution of carbon throughout particles, as well as the presence of a carbon-based surface sheath surrounding Co3O4–C particle agglomerates. Charge-discharge cycling of half-cells indicates a stable reversible discharge capacity above 800 mAh g−1. Equivalent circuit modeling of Nyquist plots show the Co3O4–C electrode has significant kinetic advantages over non-composite transition metal oxide electrodes.
Deterioration Of Dynamic Rail Pad Characteristics, Alexander Remennikov, Sakdirat Kaewunruen, Karl Ikaunieks
Deterioration Of Dynamic Rail Pad Characteristics, Alexander Remennikov, Sakdirat Kaewunruen, Karl Ikaunieks
Faculty of Engineering - Papers (Archive)
Impact loads applied to concrete sleepers, either due to the wheel flats of a train or rail abnormalities, may cause the sleepers to crack. The rail pads have been used to attenuate the effect of these impact loads on concrete sleepers and on the substructures in ballasted railway tracks. The rail pads experience high intensity loads due to wheel impacts and, as a result, the pad properties deteriorate during the service life. The consequences can be significant for the dynamic behaviour of railway tracks, interaction of vehicle and track, and impact forces on track components. However, there is currently no …
Second Order Nonlinear Inelastic Analysis Of Composite Steel–Concrete Members. I: Theory, Y. L. Pi, M. A. Bradford, B. Uy
Second Order Nonlinear Inelastic Analysis Of Composite Steel–Concrete Members. I: Theory, Y. L. Pi, M. A. Bradford, B. Uy
Faculty of Engineering - Papers (Archive)
A total Lagrangian finite element (FE) model has been formulated for the nonlinear inelastic analysis of both composite beams and columns. An accurate rotation matrix is used in the position vector analysis and nonlinear strain derivations. The slip between the steel and concrete components due to the flexible shear connection at their interface is considered as an independent displacement in the formulation which makes it easier to assign the corresponding proper slip conditions at the connections between composite beams and columns. The effects of nonlinearities and slip on the deformations and strains in the steel and concrete components, and so …
Three-Dimensional Hysteresis Of Soft Magnetic Composite, Z. W. Lin, J. G. Zhu, Y. G. Guo, Xiaolin Wang, S. Y. Ding
Three-Dimensional Hysteresis Of Soft Magnetic Composite, Z. W. Lin, J. G. Zhu, Y. G. Guo, Xiaolin Wang, S. Y. Ding
Faculty of Engineering - Papers (Archive)
Hysteresis phenomenon is one of the important characteristics of soft magnetic materials. A three-dimensional (3D) magnetic property measurement system has been developed. This system can effectively control the locus of the time-varying magnetic flux density vector B and measure the corresponding magnetic field strength vector H in a cubic sample of soft magnetic material. The sample involved in this study is a soft magnetic composite sample made of highly pure iron powder. This paper investigates the B and H loci in 3D space and the power loss when the B loci are controlled to become circles and ellipses lying in …
Transport Of Spin-Polarized Electrons In A Magnetic Superlattice , J. Liu, W. Deng, K. Xia, C. Zhang, Z. Ma
Transport Of Spin-Polarized Electrons In A Magnetic Superlattice , J. Liu, W. Deng, K. Xia, C. Zhang, Z. Ma
Faculty of Engineering - Papers (Archive)
We investigated the ballistic transport of two-dimensional electrons subjected to a periodically modulated magnetic field in the presence of the spin-orbit coupling of both the Rashba and the Dresselhaus types. It is shown that the spin splitting leads to additional gaps in the band structure and a series of minima in the transmission probability. The boundaries of the superlattice cause a finite spin polarization which can be tuned by the magnetic field, the electronic energy, and the superlattice period. The potential of such magnetic modulated structures as spin filters is discussed.
Enhanced Electrical Polarization And Ferromagnetic Moment In A Multiferroic Bifeo3/Bi3.25sm0.75ti2.98v0.02o12 Double-Layered Thin Film, Z. Cheng, Xiaolin Wang, C. V. Kannan, Kiyoshi Ozawa, H. Kimura, T. Nishida, S. Zhang, T. R. Shrout
Enhanced Electrical Polarization And Ferromagnetic Moment In A Multiferroic Bifeo3/Bi3.25sm0.75ti2.98v0.02o12 Double-Layered Thin Film, Z. Cheng, Xiaolin Wang, C. V. Kannan, Kiyoshi Ozawa, H. Kimura, T. Nishida, S. Zhang, T. R. Shrout
Faculty of Engineering - Papers (Archive)
Multiferroic BiFeO3/Bi3.25Sm0.75Ti2.98V0.02O12 double-layered thin films on Pt/Ti/SiO2/Si were fabricated using the pulsed-laser deposition technique. The films showed greatly enhanced ferroelectric and ferromagnetic properties. The values of the remanent polarization (2Pr) and coercive field (Ec) were 71.8 µC/cm2 and 148 kV/cm at a maximum applied voltage of 13 V, respectively. The value of the magnetic moment was found to be 17.5 emu/cm3. The enhancement of the polarization originated from the BiFeO3 with Bi3.25Sm0.75Ti2.98V0.02O12 working as a barrier layer. The enhancement of the magnetization is from the structural distortion of BiFeO3, due to partial epitaxial growth on the bismuth titanate surface.
Improvement Of Soft Clays Using Vacuum-Assisted Consolidation Method, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Improvement Of Soft Clays Using Vacuum-Assisted Consolidation Method, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Faculty of Engineering - Papers (Archive)
In this study, the analytical modeling of one-dimensional consolidation by vertical drains with vacuum preloading considering both vertical and horizontal drainage is presented. In this method, the total degree of consolidation based on excess pore water pressure dissipation is related to the time factor (Th), drain configuration and anisotropic soil permeability. The analytical predictions are compared with the observed data from consolidation testing. Three different test series were conducted in a large-scale consolidation apparatus designed and installed at the University of Wollongong. It is shown that the authors’ analytical model can accurately predict the laboratory behavior. Finally, the analysis of …
Spray Pyrolyzed Pbo-Carbon Nanocomposites As Anode For Lithium-Ion Batteries, S. H. Ng, J. Wang, Konstantin Konstantinov, D. Wexler, Jun Chen, Hua-Kun Liu
Spray Pyrolyzed Pbo-Carbon Nanocomposites As Anode For Lithium-Ion Batteries, S. H. Ng, J. Wang, Konstantin Konstantinov, D. Wexler, Jun Chen, Hua-Kun Liu
Faculty of Engineering - Papers (Archive)
A new approach has been used to prepare nanostructured lead oxide-carbon (PbO-C) composites via the spray pyrolysis technique. In this study, the electrochemical performance of the PbO-carbon nanocomposites as anode materials for lithium-ion rechargeable batteries was investigated. The prepared powders consist of fine nanocrystalline PbO homogeneously distributed within an amorphous carbon matrix with highly developed surface area. The estimated average crystal sizes of these nanocomposites from X-ray diffraction (XRD) patterns are in the range of 26–102nm . The combination of spray technology and carbon addition increased the specific surface area (above 6m2g−1 ) and the conductivity of PbO, improved the …
Supercurrent Transport In Yba2cu3o7–Delta Epitaxial Thin Films In A Dc Magnetic Field, V. Pan, Y. Cherpak, V. Komashko, S. Pozigun, C. Tretiatchenko, A. Semenov, E. Pashitskii, A. V. Pan
Supercurrent Transport In Yba2cu3o7–Delta Epitaxial Thin Films In A Dc Magnetic Field, V. Pan, Y. Cherpak, V. Komashko, S. Pozigun, C. Tretiatchenko, A. Semenov, E. Pashitskii, A. V. Pan
Faculty of Engineering - Papers (Archive)
Magnetic field and angle dependences of the critical current density JcH, in epitaxial c-oriented YBa2Cu3O7−delta thin films are measured by the four-probe transport current technique, low-frequency ac magnetic susceptibility, and superconducting quantum interference device magnetometry. The films under study are deposited by off-axis dc magnetron sputtering onto r-cut sapphire substrates buffered with a CeO2 layer. A consistent model of vortex pining and supercurrent limitation is developed and discussed. Rows of growthinduced out-of-plane edge dislocations forming low-angle boundaries LAB’s are shown to play a key role in achievement of the highest critical current density Jc2106 A/cm2 at 77 K. The model …
Numerical Analysis Of Matric Suction Effects Of Tree Roots, Buddhima Indraratna, Behzad Fatahi, H. Khabbaz
Numerical Analysis Of Matric Suction Effects Of Tree Roots, Buddhima Indraratna, Behzad Fatahi, H. Khabbaz
Faculty of Engineering - Papers (Archive)
The use of native vegetation in the coastal regions of Australia has become increasingly popular for stabilising railway corridors built over expansive clays and compressive soft soils. The tree roots provide three stabilising functions: (a) they reinforce the soil; (b) they dissipate excess pore pressures; and (c) they establish sufficient matric suction to increase the shear strength. The matric suction generated within the tree root zone propagates radially into the soil matrix, as a function of the moisture content change. Considering soil conditions, the type of vegetation and atmospheric conditions, a mathematical model for the rate of root water uptake …
A 70 Kiloparsec X-Ray Tail In The Cluster A3627, M. Sun, C. Jones, P. Nulsen, M. Donahue, G. M. Voit
A 70 Kiloparsec X-Ray Tail In The Cluster A3627, M. Sun, C. Jones, P. Nulsen, M. Donahue, G. M. Voit
Faculty of Engineering - Papers (Archive)
We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001, in the nearby, hot (T = 6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of ∼10. It is luminous (L0.5–2 keV ∼ 1041 ergs s-1), with a temperature of ∼0.7 keV and an X-ray Mgas of ∼109 M⊙ (∼10% of the galaxy's stellar mass). We interpret this tail as the stripped interstellar medium of ESO 137-001 mixed with the hot cluster medium, with this blue galaxy being converted into a gas-poor galaxy. Three X-ray …
Guided-Wave Thz Time-Domain Spectroscopy Of Highly Doped Silicon Using Parallel-Plate Waveguides, Rajind Mendis
Guided-Wave Thz Time-Domain Spectroscopy Of Highly Doped Silicon Using Parallel-Plate Waveguides, Rajind Mendis
Faculty of Engineering - Papers (Archive)
A novel spectroscopy technique that uses parallel-plate waveguides for the characterisation of highly conductive materials in the terahertz (THz) frequency regime is presented. This guided-wave technique resolves some of the fundamental problems associated with standard THz time-domain spectroscopy (THz-TDS) as applied to these optically dense materials. The technique is demonstrated by measuring the conductivity of highly phosphorus doped silicon
Electrochemic Properties Of Single-Wall Carbon Nanotube Electrodes, J. N. Barisci, G G. Wallace, D. Chattopadhyay, F. Papadimitrakopoulos, R. H. Baughman
Electrochemic Properties Of Single-Wall Carbon Nanotube Electrodes, J. N. Barisci, G G. Wallace, D. Chattopadhyay, F. Papadimitrakopoulos, R. H. Baughman
Faculty of Engineering - Papers (Archive)
The electrochemical properties of single-wall carbon nanotube ~CNT! electrodes in the form of sheets or papers have been examined. Thermal annealing has produced significant changes in a range of properties of the material including increased hydrophobicity and elimination of electroactive surface functional groups and other impurities. As a result of these changes, the treated electrodes exhibit lower double-layer capacitance, absence of faradaic responses and associated pseudocapacitance, and a better frequency response. The basic electrochemical behavior of the CNT paper electrodes is not markedly affected by relatively large differences in electrolyte ion size, consistent with an average pore size of 9 …
Synthesis And Characterization Of Lifepo4 And Liti0.01fe0.99po4 Cathode Materials, G. X. Wang, S. Bewlay, Scott A. Needham, Hua-Kun Liu, R. C. Liu, V. A. Drozd, J. F. Lee, J. M. Chen
Synthesis And Characterization Of Lifepo4 And Liti0.01fe0.99po4 Cathode Materials, G. X. Wang, S. Bewlay, Scott A. Needham, Hua-Kun Liu, R. C. Liu, V. A. Drozd, J. F. Lee, J. M. Chen
Faculty of Engineering - Papers (Archive)
Nanocrystalline LiFePO4 and doped LiTi0.01Fe0.99PO4 powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O K -edge X-ray absorption near-edge structure (XANES) measurements show that Ti4+ doping induces an increased unoccupied d-state in LiFePO4, resulting in an enhanced p-type semiconductivity. In situ Fe K -edge XANES measurements of Ti-doped and undoped LiFePO4 electrodes have been performed to determine the change of Fe valence during the lithium intercalation and …
Synthesis And Characterization Of One-Dimensional Cdse Nanostructures, G. X. Wang, M. S. Park, Hua-Kun Liu, D. Wexler, Jun Chen
Synthesis And Characterization Of One-Dimensional Cdse Nanostructures, G. X. Wang, M. S. Park, Hua-Kun Liu, D. Wexler, Jun Chen
Faculty of Engineering - Papers (Archive)
No abstract provided.
A Simple Means To Immobilize Enzyme Into Conducting Polymers Via Entrapment, Jun Chen, B. Winther-Jensen, C. Lynam, O Ngamna, S. Moulton, W. Zhang, G G. Wallace
A Simple Means To Immobilize Enzyme Into Conducting Polymers Via Entrapment, Jun Chen, B. Winther-Jensen, C. Lynam, O Ngamna, S. Moulton, W. Zhang, G G. Wallace
Faculty of Engineering - Papers (Archive)
No abstract provided.
Synthesis Of Chiral Polyaniline Films Via Chemical Vapor Phase Polymerization, J. Chen, B. Winther-Jensen, Y. Pornputtkul, K. West, L. Kane-Macguire, Gordon G. Wallace
Synthesis Of Chiral Polyaniline Films Via Chemical Vapor Phase Polymerization, J. Chen, B. Winther-Jensen, Y. Pornputtkul, K. West, L. Kane-Macguire, Gordon G. Wallace
Faculty of Engineering - Papers (Archive)
Electrically and optically active polyaniline films doped with (1R)-(-)-10-camphorsulfonic acid were successfully deposited on nonconductive substrates via chemical vapor phase polymerization. The above polyaniline∕R-camphorsulfonate films were characterized by electrochemical and physical methods, such as cyclic voltammetry (CV), UV-vis spectroscopy, four-point probe conductivity measurement, Raman spectroscopy, circular dichroism spectroscopy, and scanning electron microscopy. The poly aniline films grown by this method not only showed high electrochemical activity, supported by CV and Raman spectrum, but also exhibited optical activity corresponding to the polymer chains as observed by circular dichroism spectra.
Drastic Improvement Of Surface Structure And Current-Carrying Ability In Yba2cu3o7 Films By Introducing Multilayered Structure, Alexey Pan, Serhiy V. Pysarenko, S X. Dou
Drastic Improvement Of Surface Structure And Current-Carrying Ability In Yba2cu3o7 Films By Introducing Multilayered Structure, Alexey Pan, Serhiy V. Pysarenko, S X. Dou
Faculty of Engineering - Papers (Archive)
Much smoother surfaces and significantly improved superconducting properties of relatively thick YBa2Cu3O7 (YBCO) films have been achieved by introducing a multilayered structure with alternating main YBCO and additional NdBCO layers. The surface of thick (1 µm) multilayers has almost no holes compared to YBCO films. Critical current density (Jc) has been drastically increased up to a factor >3 in 1 µm multilayered structures compared to YBCO films over entire temperature and applied magnetic field range. Moreover, Jc values measured in thick multilayers are even larger than in much thinner YBCO films. The Jc and surface improvement have been analyzed and …