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Full-Text Articles in Engineering

Effect Of Frozen Spin On The Magnetocaloric Property Of La0.7ca0.3coo3 Polycrystalline And Single Crystal Samples, J C. Debnath, R Zeng, J H. Kim, P Shamba, Dapeng Chen, S X. Dou Jan 2012

Effect Of Frozen Spin On The Magnetocaloric Property Of La0.7ca0.3coo3 Polycrystalline And Single Crystal Samples, J C. Debnath, R Zeng, J H. Kim, P Shamba, Dapeng Chen, S X. Dou

Australian Institute for Innovative Materials - Papers

Polycrystalline (PC) and single crystalline (SC) samples of La0.7Ca0.3CoO3 (LCCO) with the perovskite structure were synthesized by conventional solid-state reaction and the floating-zone growth method. We conducted isothermal magnetization measurements of the PC and SC samples at temperatures from 2.8 K to 140 K, and evaluated the magnetic entropy change (−ΔSM) under zero field cooling (ZFC) and field cooling (FC) to 2.8 K. An interesting result has been obtained, where the −ΔSM–T curves in the low temperature range show totally different features between the ZFC and FC cooling procedures. The −ΔS …


Effect Of Grain Size On The Hydrogen Diffusion Process In Steel Using Cellular Automaton Approach, Druce P. Dunne, E V. Pereloma, Nima Yazdipour Jan 2012

Effect Of Grain Size On The Hydrogen Diffusion Process In Steel Using Cellular Automaton Approach, Druce P. Dunne, E V. Pereloma, Nima Yazdipour

Faculty of Engineering - Papers (Archive)

The role of microstructure in susceptibility to hydrogen uptake and property degradation is being evaluated using a number of high strength pipeline steels. To do so, a cellular automaton (CA) model has been used to examine the effect of grain size, as a first step in assessing the influence of microstructure. The simulation results of hydrogen diffusion into microstructures with different grain sizes are presented.


Effect Of Gas Atmosphere On Carbothermal Reduction And Nitridation Of Titanium Dioxide, Sheikh A. Rezan, Guangqing Zhang, Oleg Ostrovski Jan 2012

Effect Of Gas Atmosphere On Carbothermal Reduction And Nitridation Of Titanium Dioxide, Sheikh A. Rezan, Guangqing Zhang, Oleg Ostrovski

Faculty of Engineering - Papers (Archive)

This article examined the reduction/nitridation of rutile in the He-N2, Ar-N2, and He (Ar)-H2- N2 gas mixtures, as well as pure nitrogen, in the temperature-programmed and isothermal experiments in a fixed-bed reactor. The extents of reduction and nitridation were determined from the off gas composition and LECO analysis. The off-gas composition was monitored using the infrared sensor (CO, CO2, and CH4) and dew point analyzer (H2O). The phase composition of the reduced samples was analyzed using X-ray diffraction (XRD). The temperature and gas composition had a strong effect on the rutile reduction. The reduction was the fastest in the H2- …


Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn Jan 2012

Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn

Faculty of Engineering - Papers (Archive)

This study was focused on the effects of compaction energy on the dynamic properties of a silty sand in its as-compacted state in relation to the measured values of matric suction. The influence of the imparted energy on the shear wave velocity and the small-strain shear modulus of the compacted soil was studied for three different energy levels that correspond to the standard Proctor as well as reduced and enhanced. The specimens were prepared with moisture contents ranging from the dry to wet of optimum, and subsequently compacted to known dry unit weights for which the corresponding matric suction and …


Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna Jan 2012

Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Faculty of Engineering - Papers (Archive)

A system of vertical drains (PVDs) with preloading is a successful method for promoting horizontal drainage and accelerating soil consolidation. A piecewise technique is used to capture the radial consolidation in the multi-layer soil system to incorporate (a) the effect of soil downdrag and (b) smear zone where soil permeability varying linearly. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of required time for consolidation. It can be seen that the consolidation of the multi layer soil depends on the interaction between 2 adjacent layer, penetration depth, and …


Effect Of Coal Fines On The Shear Strength And Deformation Characteristics Of Ballast, S S. Nimbalkar, Buddhima Indraratna, Cholachat Rujikiatkamjorn, M Martin Jan 2012

Effect Of Coal Fines On The Shear Strength And Deformation Characteristics Of Ballast, S S. Nimbalkar, Buddhima Indraratna, Cholachat Rujikiatkamjorn, M Martin

Faculty of Engineering - Papers (Archive)

Ballast is the most common material supporting the rail track structure due to its large shear strength, high load bearing capacity and free-drainage. However, the fouling of ballast effects deterioration of track performance, and eventually demands track cleaning. Fouling refers to the progressive intrusion of fines into the ballast layer and subsequently filling the voids. Coal spilling from wagons during transport, sleeper and ballast degradation and soil pumping from soft subgrade are the major factors contributing to ballast fouling. Queensland rail network suffers mainly due to ballast breakdown and intrusion of coal fines. The maintenance costs of ballasted tracks can …


The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn Jan 2012

The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn

Faculty of Engineering - Papers (Archive)

In this paper, cyclic triaxial loading tests were conducted on specimens of soft clay with varying cyclic stresses and frequencies to investigate the performance of soft soil subgrade subjected to cyclic loading. The laboratory results indicate that given the same level of cyclic stress, the stability of clay subgrade is primarily dependent on the loading time with no consistent frequency/train speed effect. There exists a critical level of cyclic stress between 60 and 80% of the monotonic shear strength, above which failure may occur regardless of the loading frequency. The nature that soils behave dependently on cyclic stress level rather …


Effect Of Annealing On The Microstructure, Texture And Mechanical Properties Of Severely Deformed Interstitial Free Steel, Sujoy S. Hazra, Azdiar A. Gazder, E V. Pereloma Jan 2012

Effect Of Annealing On The Microstructure, Texture And Mechanical Properties Of Severely Deformed Interstitial Free Steel, Sujoy S. Hazra, Azdiar A. Gazder, E V. Pereloma

Faculty of Engineering - Papers (Archive)

Ti-stabilised interstitial free (IF) steel initially subjected to 8 passes, route BC equal channel angular pressing (ECAP) was further cold rolled (CR) at room temperature to 95% thickness reduction. Both samples were isothermally annealed at 710 °C following which their microstructures and micro-textures were compared via electron back-scattering diffraction (EBSD). The mechanical properties first obtained by shear punch testing (SPT) were later corroborated by uniaxial tensile tests. In the case of the ECAP material, continuous recrystallisation is followed by abnormal growth at prolonged annealing times with minor increases in high angle boundary (HAGB) fraction. On the other hand, the …


The Effect Of Reduced Graphene Oxide Addition On The Superconductivity Of Mgb2, K S. B De Silva, S Gambhir, Xiaolin Wang, X Xu, W X. Li, David L. Officer, D Wexler, G G. Wallace, S. X. Dou Jan 2012

The Effect Of Reduced Graphene Oxide Addition On The Superconductivity Of Mgb2, K S. B De Silva, S Gambhir, Xiaolin Wang, X Xu, W X. Li, David L. Officer, D Wexler, G G. Wallace, S. X. Dou

Faculty of Engineering - Papers (Archive)

Reduced graphene oxide (rGO) and highly reduced chemically converted graphene (ICCO) samples were prepared under different processing condition! and were doped into MgBz by a diffusion process at 800 °C for 10 houn. It was demonstrated that a small addition rCCG can significantly improve the supcn;onducting properties of MgBz. Doping of M8B2 with 1 mol% of rCCG resulted in a Ie of 5.45 X lOS A cm-2 at 20 K in self-fields, which il nearly 32% improvement over that of the undopcd sample. This is a significant improvement as most carbon sources adversely affect the Ie performance: at the zero …


Terahertz Photon Mixing Effect In Gapped Graphene, Yee Sin Ang, Shareef Sultan, Asya Tawfiq, Juncheng Cao, Chao Zhang Jan 2012

Terahertz Photon Mixing Effect In Gapped Graphene, Yee Sin Ang, Shareef Sultan, Asya Tawfiq, Juncheng Cao, Chao Zhang

Faculty of Engineering - Papers (Archive)

We theoretically calculate the terahertz waves mixing effect in doped graphene with a finite bandgap. The temperature dependence of the nonlinear intraband optical response at bandgap opening of few tens of meVare investigated. When the external electric field is weak, a moderate level of bandgap opening is found to slightly enhance the nonlinear optical response. The optical response is however significantly altered under strong-field condition. The strong-field nonlinear optical conductivity exhibits two distinct response ‘hot spot’: (i) low temperature with large bandgap and (ii) high temperature with small bandgap. The electric field required for the nonlinear response to dominate over …


"Oxygen-Vacancy Effect On Structural, Magnetic, And Ferroelectric Properties In Multiferroic Ymno3 Single Crystals", Dapeng Chen, Yi Du, Xiaolin Wang, Zhenxiang Cheng, S. X. Dou, Zhi W. Lin, Jian G. Zhu, Bo Xu Jan 2012

"Oxygen-Vacancy Effect On Structural, Magnetic, And Ferroelectric Properties In Multiferroic Ymno3 Single Crystals", Dapeng Chen, Yi Du, Xiaolin Wang, Zhenxiang Cheng, S. X. Dou, Zhi W. Lin, Jian G. Zhu, Bo Xu

Faculty of Engineering - Papers (Archive)

"We have investigated the structural, magnetic, and ferroelectric properties of magnetically frustrated multiferroic YMnO3 single crystals. The ferroelectric domain structures of YMnO3 samples were studied by piezoresponse force microscopy. Instead of domain vortex structure in stoichiometric crystals, YMnO3-delta exhibits a random domain configuration with straight domain walls. In magnetic measurements, the YMnO3-delta crystal shows typical antiferromagnetic behavior with higher Neel temperature and lower magnetization compared to the stoichiometric sample. The ordered oxygen vacancies dominate multiferroicity through tailoring the domain wall structure. (C) 2012 American Institute of Physics. [doi:10.1063/1.3676000]"


Long-Distance Walking Effect On Below-Knee Amputee Compensatory Gait Patterns And Implications On Prosthetic Designs And Training, L F. Yeung, Aaron Leung, Ming Zhang, Winson Lee Jan 2012

Long-Distance Walking Effect On Below-Knee Amputee Compensatory Gait Patterns And Implications On Prosthetic Designs And Training, L F. Yeung, Aaron Leung, Ming Zhang, Winson Lee

Faculty of Engineering and Information Sciences - Papers: Part A

Trans-tibial amputees are advised to walk as much as able people to achieve healthy and independent life. However, they usually have difficulties in doing so. Previous researches only included data from a few steps when studying the gait of amputees. Walking over a long distance was rarely examined. The objective of this study was to investigate the changes in spatial-temporal, kinetic and kinematic gait parameters of trans-tibial amputees after long-distance walking. Six male unilateral trans-tibial amputees performed two sessions of 30-min walking on a level treadmill at their self-selected comfortable speed. Gait analysis was undertaken over-ground: (1) before walking, (2) …


Semi-Analytical Solutions For Cubic Autocatalytic Reaction-Diffusion Equations; The Effect Of A Precursor Chemical, Muteb Alharthi, Timothy Marchant, Mark Nelson Jan 2012

Semi-Analytical Solutions For Cubic Autocatalytic Reaction-Diffusion Equations; The Effect Of A Precursor Chemical, Muteb Alharthi, Timothy Marchant, Mark Nelson

Faculty of Engineering and Information Sciences - Papers: Part A

Semi-analytical solutions for a cubic autocatalytic reaction, with linear decay and a precursor chemical, are considered. The model is coupled with diffusion and considered in a one-dimensional reactor. In this model the reactant is supplied by two mechanisms, diffusion via the cell boundaries and decay of an abundant precursor chemical present in the reactor. The Galerkin method is used to approximate the spatial structure of the reactant and autocatalyst concentrations in the reactor. Ordinary differential equations are then obtained as an approximation to the governing partial differential equations and analyzed to obtain semi-analytical results for the reaction-diffusion cell. Singularity theory …


Effect Of The Austenitising Heat Treatment On The Microstructure And Hardness Of Martensitic Stainless Steel Aisi 420, Lilian D. Barlow, Madeleine Du Toit Jan 2012

Effect Of The Austenitising Heat Treatment On The Microstructure And Hardness Of Martensitic Stainless Steel Aisi 420, Lilian D. Barlow, Madeleine Du Toit

Faculty of Engineering and Information Sciences - Papers: Part A

The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 C, followed …


Effect Of Gallium Doping And Ball Milling Process On The Thermoelectric Performance Of N-Type Zno, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou Jan 2012

Effect Of Gallium Doping And Ball Milling Process On The Thermoelectric Performance Of N-Type Zno, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou

Faculty of Engineering and Information Sciences - Papers: Part A

We report a systematic investigation of the thermoelectric properties of n-type Ga-doped ZnO synthesized using different ball milling conditions. Samples fabricated by the high-energy ball milling resulted in a highly dense layered structure with randomly distributed voids. These samples measured the lowest room temperature thermal conductivity, i.e., 27 W/mK due to increased phonon scattering. Furthermore, the Ga:ZnO system showed a metal–semiconductor transition above 300 K with transition temperature decreasing with increasing doping level. Measurement of the activation energy revealed the presence of one donor level around 3.9–7.8 meV and a deeper donor level around 15.4–18.1 meV below the conduction band …


The Effect Of Incomplete Mixing Upon The Belousov-Zhabotinskii Reaction, Ahmed Hussein Msmali, Mark I. Nelson, Maureen P. Edwards Jan 2012

The Effect Of Incomplete Mixing Upon The Belousov-Zhabotinskii Reaction, Ahmed Hussein Msmali, Mark I. Nelson, Maureen P. Edwards

Faculty of Engineering and Information Sciences - Papers: Part A

The aim of this research to investigate the effect of incomplete mixing upon the existence of periodic solutions. To this end we study the behaviour of the Belousov- Zhabotinskii (B-Z) reaction in a batch reactor. The B-Z reaction is a well studied chemical system that exhibits periodic behaviour. Furthermore, simplified mathematical models exist which have been validated both against experimental data and larger chemical mechanisms. Specifically, we study the `Oregonator' model for the B-Z reaction due to Field and Noyes (1974). This consists of five chemical reactions involving three independent chemical intermediates. We extend this model by combining it with …


On The Dosimetric Effect And Reduction Of Inverse Consistency And Transitivity Errors In Deformable Image Registration For Dose Accumulation, Edward T. Bender, Nicholas Hardcastle, Wolfgang A. Tome Jan 2012

On The Dosimetric Effect And Reduction Of Inverse Consistency And Transitivity Errors In Deformable Image Registration For Dose Accumulation, Edward T. Bender, Nicholas Hardcastle, Wolfgang A. Tome

Faculty of Engineering and Information Sciences - Papers: Part A

Purpose: Deformable image registration (DIR) is necessary for accurate dose accumulation between multiple radiotherapy image sets. DIR algorithms can suffer from inverse and transitivity inconsistencies. When using deformation vector fields (DVFs) that exhibit inverse-inconsistency and are nontransitive, dose accumulation on a given image set via different image pathways will lead to different accumulated doses. The purpose of this study was to investigate the dosimetric effect of and propose a postprocessing solution to reduce inverse consistency and transitivity errors. Methods: Four MVCT images and four phases of a lung 4DCT, each with an associated calculated dose, were selected for analysis. DVFs …


Terahertz Photon Mixing Effect In Graphene And Topological Insulator, Yee Sin Ang, Qinjun Chen, Xiaolin Wang, R A. Lewis, Chao Zhang Jan 2012

Terahertz Photon Mixing Effect In Graphene And Topological Insulator, Yee Sin Ang, Qinjun Chen, Xiaolin Wang, R A. Lewis, Chao Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

We theoretically investigate the nonlinear terahertz photon-mixing effect in graphene and topological insulator. We show that the nonlinear intraband optical absorption in both materials dominate over the linear response under a very moderate external electric field strength. The nonlinear response is thermally enhanced and the optical nonlinearity is well-preserved even in high temperature regime.


Effect Of Manganese Content And Microstructure On The Susceptibility Of X70 Pipeline Steel To Hydrogen Cracking, D Hejazi, A J. Haq, N Yazdipour, D P. Dunne, A Calka, Frank J. Barbaro, E V. Pereloma Jan 2012

Effect Of Manganese Content And Microstructure On The Susceptibility Of X70 Pipeline Steel To Hydrogen Cracking, D Hejazi, A J. Haq, N Yazdipour, D P. Dunne, A Calka, Frank J. Barbaro, E V. Pereloma

Faculty of Engineering and Information Sciences - Papers: Part A

The influence of composition and microstructure on susceptibility to hydrogen induced cracking (HIC) was investigated in high strength pipeline steels, with Mn contents of 1.2% (standard, X70), and 0.5% (medium, MX70). The HIC resistance of the simulated coarse grained heat affected zone microstructures and normalized X70 transfer bar was also investigated. Notched and fatigue pre-cracked samples were charged with hydrogen prior to three point bend tests. The conditional fracture toughness JQ was determined. The results are discussed in relation to grain size, microstructure, composition and the type and distribution of non-metallic inclusions and precipitates.


Effect Of Coiling Temperature On Oxide Scale Of Hot-Rolled Strip, Xianglong Yu, Zhengyi Jiang, Xiaodong Wang, Dongbin Wei, Quan Yang Jan 2012

Effect Of Coiling Temperature On Oxide Scale Of Hot-Rolled Strip, Xianglong Yu, Zhengyi Jiang, Xiaodong Wang, Dongbin Wei, Quan Yang

Faculty of Engineering and Information Sciences - Papers: Part A

The influence of the coiling temperature, ranging from 550 to 570℃, on the morphology and the phase composition of the oxide scale formed on the microalloyed low carbon steel for automobiles after hot strip rolling was investigated. Physicochemical characteristics of the oxide scales were examined and their formation mechanism was discussed. Thickness of the oxide scale is in the range of 8-11μm and decreases with a decrease of coiling temperature. The microstructure and phase composition, XRD analysis shows a large amount of magnetite (Fe3O4) and some sparse hematite (Fe2O3) exist on the surface of hot rolled strip when the coiling …


The Effect Of Chromium Addition On The Strain Ageing And Recrystallisation Behaviour Of Low Carbon Steel, Elena Pereloma, V Bata, Azdiar A. Gazder Jan 2012

The Effect Of Chromium Addition On The Strain Ageing And Recrystallisation Behaviour Of Low Carbon Steel, Elena Pereloma, V Bata, Azdiar A. Gazder

Faculty of Engineering and Information Sciences - Papers: Part A

The strain ageing and recrystallisation behaviour of conventional low carbon A06 steel was compared with those containing varying amounts of chromium (0.26, 0.52 and 0.74 wt.%). The results show that the A06 steel undergoes four stages of strain ageing: (i) the pinning by solute atoms of dislocations generated during pre-strain, (ii) the generation of fresh dislocations from grain boundaries, (iii) the onset of precipitation and, (iv) the inhibition of dislocation generation from grain boundaries due to pinning by carbon segregation. On the other hand, the chromium containing steels only exhibit the fIrst three stages of strain ageing. An approximately twofold …


Effect Of A Static Magnetic Field On Nanodosimetric Quantities In A Dna Volume, Peter Lazarakis, Marion U. Bug, Elisabetta Gargioni, Susanna Guatelli, Sabastien Incerti, Hans Rabus, Anatoly B. Rosenfeld Jan 2012

Effect Of A Static Magnetic Field On Nanodosimetric Quantities In A Dna Volume, Peter Lazarakis, Marion U. Bug, Elisabetta Gargioni, Susanna Guatelli, Sabastien Incerti, Hans Rabus, Anatoly B. Rosenfeld

Faculty of Engineering - Papers (Archive)

Abstract Purpose: With the advent of magnetic resonance imaging (MRI)-guided radiation therapy it is becoming increasingly important to consider the potential influence of a magnetic field on ionising radiation. This paper aims to study the effect of a magnetic field on the track structure of radiation to determine if the biological effectiveness may be altered. Methods: Using the Geant4-DNA (GEometry ANd Tracking 4) Monte Carlo simulation toolkit, nanodosimetric track structure parameters were calculated for electrons, protons and alpha particles moving in transverse magnetic fields up to 10 Tesla. Applying the model proposed by Garty et al., the track structure parameters …


Rietveld Analysis Of The Effect Of Annealing Atmosphere On Phase Evolution Of Nanocrystalline Tio 2 Powders, M Salari, M Rezaee, A T. Chidembo, Konstantin Konstantinov, Hua-Kun Liu Jan 2012

Rietveld Analysis Of The Effect Of Annealing Atmosphere On Phase Evolution Of Nanocrystalline Tio 2 Powders, M Salari, M Rezaee, A T. Chidembo, Konstantin Konstantinov, Hua-Kun Liu

Faculty of Engineering and Information Sciences - Papers: Part A

The struclUral evolution of nanocrystaUine Ti02 was studied by X-ray diffraction (XRD) and the Rietveld refinement method (RRM). Ti02 powders were prepared by the sol-gel technique. Post annealing of as·synthesized powders in the temperature range from 500°C to 600 °C under air and argon atmospheres led to the formation of Ti02 nanoparticles with mean crystallite size in the range of 37-165 nm. based on the Rietveld refinement results. It was found that the phase structure, composition, and crystallite size of the resulting particles were dependent on not only the annealing temperature, but also the annealing atmosphere. Rietveld refinement of the …


Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou Jan 2012

Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

YFeO3 single crystal displays two relaxor-like dielectric relaxations, one at low temperature (170300 K) and one at high temperature (370520 K), which are attributed to the activation of electrons and oxygen vacancies, respectively. Above the temperature at which electrons are activated, the sample displays a large magnetocapacitance effect. Comparison of the impedance Cole-Cole plots measured with and without applied magnetic field reveals that the occurrence of magnetocapacitance effect is accompanied with an increasing in DC conductivity under magnetic field after the activation of electrons, which is explained by the enhancement of electron jumping in Fe2b-O-Fe3b chains by magnetic field. Thus …


Magnetovolume Effect In Ho2fe17-Xmnx Compounds, Jianli Wang, A J. Studer, S J. Kennedy, R Zeng, S. X. Dou, S J. Campbell Jan 2012

Magnetovolume Effect In Ho2fe17-Xmnx Compounds, Jianli Wang, A J. Studer, S J. Kennedy, R Zeng, S. X. Dou, S J. Campbell

Faculty of Engineering - Papers (Archive)

The structural and magnetic properties of seven compounds in the Ho2Fe17-xMnx series (x = 0-5) have been investigated. The spontaneous magnetization Ms at 10 K exhibits a minimum at x ≈ 3.8 while the 3d-sublattice magnetization MT is found to decrease at ∼ −3.4 μB/per Mn atom compared with the rate of ∼−2.0 μB/per Mn atom expected from a simple dilution model. All of the Ho2Fe17-xMnx compounds exhibit anisotropic thermal expansion below their Curie temperatures leading to the presence of strong magnetovolume …


Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou Jan 2012

Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou

Faculty of Engineering - Papers (Archive)

A nanostructured honeycomb lattice consisting of MnPS3 nanoparticles synthesized via the ion-exchange technique was found to have restacked molecular layers stabilized by H2O insertion between the layers. Susceptibility (χ) and heat capacity measurements showed the absence of long range magnetic ordering, at least down to 2 K. However, the χ data showed that the system possesses a high effective Curie temperature, suggesting that the system is in a high spin lattice disordered state. Evaluation of the magnetocaloric effect indicates that the system has a large reversible magnetic-entropy change (−ΔSm) of 6.8 and 12.8 J/kg K …


Probing And Modelling The Localized Self-Mixing In A Gan/Algan Field-Effect Terahertz Detector, J D. Sun, H Qin, R A. Lewis, Y F. Sun, X Y. Zhang, Y Cai, D M. Wu, B S. Zhang Jan 2012

Probing And Modelling The Localized Self-Mixing In A Gan/Algan Field-Effect Terahertz Detector, J D. Sun, H Qin, R A. Lewis, Y F. Sun, X Y. Zhang, Y Cai, D M. Wu, B S. Zhang

Faculty of Engineering - Papers (Archive)

In our previous work, we inferred the existence of localized self-mixing in an antenna-coupled field-effect terahertz detector. In this Letter, we report a quasistatic self-mixing model taking into account the localized terahertz fields and its verification by comparing the simulated results with the experimental data in a two-dimensional space of the gate voltage and the drain/source bias. The model well describes the detector characteristics: not only the magnitude, but also the polarity, of the photocurrent can be tuned. The existence of strongly localized self-mixing in such detectors is confirmed.