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Articles 1 - 30 of 59
Full-Text Articles in Engineering
Thermionic Cooling Of Optoelectronic And Microelectronic Devices, S. P. Lee, B. C. Lough, R. A. Lewis, C. Zhang
Thermionic Cooling Of Optoelectronic And Microelectronic Devices, S. P. Lee, B. C. Lough, R. A. Lewis, C. Zhang
Faculty of Engineering - Papers (Archive)
Solid-state thermionic cooling has gained attention recently because of its potential high cooling power. Thermionic devices based on semiconductor heterostructures utilize the band-edge offset at a heterojunction as the thermionic emission potential barrier and a thin layer to separate the cold and hot junction. In this paper, we present the behavior of thermionic coolers with periodic barriers using gallium arsenide/aluminium gallium arsenide (GaAs/Al/sub x/Ga/sub 1-x/As) semiconductor heterostructures. The exact numerical calculation to model the device performance has shown that the thermal efficiency in a multilayer structure is optimised when the effect of phonon scattering is introduced in the model. Besides, …
Chandra Observation Of Abell 2142: Survival Of Dense Subcluster Cores In A Merger, M. Markevitch, T. J. Ponman, P. Nulsen, M. W. Bautz, D. J. Burke, L. P. David, D. Davis, R. H. Donnelly, W. R. Forman, C. Jones, J. Kaastra, E. Kellogg, D. W. Kim, J. Kolodziejczak, P. Mazzotta, A. Pagliaro, S. Patel, L. Van Speybroeck, A. Vikhlinen, J. Vrtilek, M. Wise, P. Zhao
Chandra Observation Of Abell 2142: Survival Of Dense Subcluster Cores In A Merger, M. Markevitch, T. J. Ponman, P. Nulsen, M. W. Bautz, D. J. Burke, L. P. David, D. Davis, R. H. Donnelly, W. R. Forman, C. Jones, J. Kaastra, E. Kellogg, D. W. Kim, J. Kolodziejczak, P. Mazzotta, A. Pagliaro, S. Patel, L. Van Speybroeck, A. Vikhlinen, J. Vrtilek, M. Wise, P. Zhao
Faculty of Engineering - Papers (Archive)
We use Chandra data to map the gas temperature in the central region of the merging cluster A2142. The cluster is markedly nonisothermal; it appears that the central cooling flow has been disturbed but not destroyed by a merger. The X-ray image exhibits two sharp, bow-shaped, shocklike surface brightness edges or gas density discontinuities. However, temperature and pressure profiles across these edges indicate that these are not shock fronts. The pressure is reasonably continuous across these edges, while the entropy jumps in the opposite sense to that in a shock (i.e., the denser side of the edge has lower temperature, …
Internal Transitions Of Confined Neutral Magnetoexcitons In Gaas/Alxga1–Xas Quantum Wells, H. A. Nickel, G. Kioseoglou, T. Yeo, H. D. Cheong, A. Petrou, B. D. Mccombe, D. Broido, K. K. Bajaj, R. A. Lewis
Internal Transitions Of Confined Neutral Magnetoexcitons In Gaas/Alxga1–Xas Quantum Wells, H. A. Nickel, G. Kioseoglou, T. Yeo, H. D. Cheong, A. Petrou, B. D. Mccombe, D. Broido, K. K. Bajaj, R. A. Lewis
Faculty of Engineering - Papers (Archive)
Optically detected resonance spectroscopy has been used to study resonant absorption of electrons, holes, and their complexes in GaAs/AlxGa1–xAs quantum wells (QW's) in magnetic fields up to 15 T. In undoped multiple-QW samples with well widths of 12.5, 15, and 20 nm, in addition to an electron and two hole cyclotron resonances, 1s-->np+,– (in the hydrogenic notation) internal exciton transitions (IET's) arising from two distinct neutral heavy-hole magneto-excitons were observed. The unique capability of observing electron and hole cyclotron resonance as well as several IET's in a single sample permitted verification of a predicted relationship resulting from the symmetry …
Characterisation Of Indium Phosphide Using Terahertz Radiation, R. L. Causley, R. A. Lewis
Characterisation Of Indium Phosphide Using Terahertz Radiation, R. L. Causley, R. A. Lewis
Faculty of Engineering - Papers (Archive)
Specimens of undoped, n-type and p-type bulk InP have been investigated using THz radiation. Reflection spectroscopy permits the determination of the TO and LO phonon energies as well as the carrier concentration. Absorption spectroscopy reveals transitions between impurity states. We report the first absorption spectrum of an acceptor in InP. The transition energies agree well with electronic Raman scattering and photoluminescence data.
Population Inversion In An Optically-Pumped Single Quantum Well, T. J. Green, W. Xu
Population Inversion In An Optically-Pumped Single Quantum Well, T. J. Green, W. Xu
Faculty of Engineering - Papers (Archive)
An optically-pumped intersubband laser generator is proposed in which the continuum states above an Al0.2Ga0.8As-GaAs-Al0.2Ga0.8 As single quantum well with a width of L=17 nm serve as the highest level in a four-level laser system. The design allows much greater flexibility in the choice of pumping source and simplifies considerably the device fabrication. We have obtained the electrode subband structure of the proposed device and utilized a simple rate equation approach to examine the electron density in different states under optical pumping.
Chandra X-Ray Observations Of The Hydra A Cluster: An Interaction Between The Radio Source And The X-Ray–Emitting Gas, B. R. Mcnamara, M. Wise, P. Nulsen, L. P. David, C. L. Sarazin, M. Bautz, M. Markevitch, A. Vikhlinin, W. R. Forman, C. Jones, D. E. Harris
Chandra X-Ray Observations Of The Hydra A Cluster: An Interaction Between The Radio Source And The X-Ray–Emitting Gas, B. R. Mcnamara, M. Wise, P. Nulsen, L. P. David, C. L. Sarazin, M. Bautz, M. Markevitch, A. Vikhlinin, W. R. Forman, C. Jones, D. E. Harris
Faculty of Engineering - Papers (Archive)
We present Chandra X-ray observations of the Hydra A cluster of galaxies, and we report the discovery of structure in the central 80 kpc of the cluster's X-ray-emitting gas. The most remarkable structures are depressions in the X-ray surface brightness, ~25-35 kpc in diameter, that are coincident with Hydra A's radio lobes. The depressions are nearly devoid of X-ray-emitting gas, and there is no evidence for shock-heated gas surrounding the radio lobes. We suggest that the gas within the surface brightness depressions was displaced as the radio lobes expanded subsonically, leaving cavities in the hot atmosphere. The gas temperature declines …
Piezospectroscopy Of The P3/2 And Fano Series Of Singly Ionized Zinc In Germanium, G. Piao, P. Fisher, R. A. Lewis
Piezospectroscopy Of The P3/2 And Fano Series Of Singly Ionized Zinc In Germanium, G. Piao, P. Fisher, R. A. Lewis
Faculty of Engineering - Papers (Archive)
The absorption spectrum of singly ionized zinc in Ge has been studied using Fourier spectroscopy. Improved experimental conditions give more details for the p3/2 series than previously. Quantitative piezospectroscopy has been performed with compression along <111> and <100>. It is deduced that the final states of the compound C line include 1Gamma7-, 3Gamma8-, 3Gamma8+, and 4Gamma8+. More reliable deformation potential constants of some energy states have been obtained. Fano resonances associated with bound-hole states have been studied with and without applied uniaxial compression. The piezospectroscopic behavior of these is compared with that of the parent p3/2 series.
Chandra X-Ray Detection Of The Radio Hot Spots Of 3c 295, D. E. Harris, P. Nulsen, T. J. Ponman, M. Bautz, R. A. Cameron, L. P. David, R. H. Donnelly, W. R. Forman, L. Grego, M. J. Hardcastle, J. P. Henry, C. Jones, J. P. Leahy, M. Markevitch, A. R. Martel, B. R. Mcnamara, P. Mazzotta, W. Tucker, S. N. Virani, J. Vrtilek
Chandra X-Ray Detection Of The Radio Hot Spots Of 3c 295, D. E. Harris, P. Nulsen, T. J. Ponman, M. Bautz, R. A. Cameron, L. P. David, R. H. Donnelly, W. R. Forman, L. Grego, M. J. Hardcastle, J. P. Henry, C. Jones, J. P. Leahy, M. Markevitch, A. R. Martel, B. R. Mcnamara, P. Mazzotta, W. Tucker, S. N. Virani, J. Vrtilek
Faculty of Engineering - Papers (Archive)
An observation of the radio galaxy 3C 295 during the calibration phase of the Chandra X-Ray Observatory reveals X-ray emission from the core of the galaxy, from each of the two prominent radio hot spots, and from the previously known cluster gas. We discuss the possible emission processes for the hot spots and argue that a synchrotron self-Compton (SSC) model is preferred for most or all of the observed X-ray emission. SSC models with near-equipartition fields thus explain the X-ray emission from the hot spots in the two highest surface brightness FR II radio galaxies, Cygnus A and 3C 295. …
Evaluation Of Surface And Groundwater Management Strategies For Drained Sulfidic Soil Using Numerical Models, B. Blunden, Buddhima Indraratna
Evaluation Of Surface And Groundwater Management Strategies For Drained Sulfidic Soil Using Numerical Models, B. Blunden, Buddhima Indraratna
Faculty of Engineering - Papers (Archive)
The effective management of acid sulfate soils is a major issue for many coastal regions in Australia. Simulations were conducted to evaluate 4 different water management strategies that could be applied to agricultural land on the south coast of New South Wales, Australia, to minimise acid generation from acid sulfate soils. The water management strategies are compared with the existing extensively drained situation which generates and discharges large quantities of acidic pyrite oxidation products. The 4 water management strategies include elevated drain water levels using a weir, 25 mm irrigation on a 7- or 14- day cycle, and elevated drain …
A Computational Technique For Simulating Ionization Energy Deposition By Energetic Ions In Complex Targets, I. Cornelius, Anatoly B. Rosenfeld, P. D. Bradley, R. L. Maughan
A Computational Technique For Simulating Ionization Energy Deposition By Energetic Ions In Complex Targets, I. Cornelius, Anatoly B. Rosenfeld, P. D. Bradley, R. L. Maughan
Faculty of Engineering - Papers (Archive)
An ion transport code was developed for simulating ionization energy deposition by energetic ions in sensitive volumes of complex structures. The code was used to simulate recent microdosimetry measurements performed with silicon-on-insulator (SOI) microdosimeters in Fast Neutron Therapy (FNT).
A New Silicon Detector For Microdosimetry Applications In Proton Therapy, Anatoly B. Rosenfeld, P. Bradley, I. Cornelius, G. I. Kaplan, B. J. Allen, J. B. Flanz, M. Goitein, A. Van Meerbeeck, J. Schubert, J. Bailey, Y. Takada, A. Maruhashi, Y. Hayakawa
A New Silicon Detector For Microdosimetry Applications In Proton Therapy, Anatoly B. Rosenfeld, P. Bradley, I. Cornelius, G. I. Kaplan, B. J. Allen, J. B. Flanz, M. Goitein, A. Van Meerbeeck, J. Schubert, J. Bailey, Y. Takada, A. Maruhashi, Y. Hayakawa
Faculty of Engineering - Papers (Archive)
A silicon-on-insulator diode array with a sensitive depth of 10 microns has been developed for microdosimetry in proton therapy. The detector was coupled to a radiation-hard charge sensitive amplifier with the probe assembly capable of measuring an LET down to 1.2 keV/μm. The device has been successfully tested at two proton therapy centers. The 230 MeV Northeastern Proton Therapy Center, Boston and the 250 MeV Proton Medical Research Center at Tsukuba, Japan. The device offers much improved spatial resolution compared with a proportional gas counter particularly in the critical high dose region around the proton Bragg peak. Due to its …
Design And Simulation Of Continuous Scintillator With Pixellated Photodetector, G. J. Takacs, Anatoly B. Rosenfeld, M. L. Lerch, S. W. Lindsay, G. N. Taylor, S. R. Meikle, S. Eberl, V. L. Perevertailo
Design And Simulation Of Continuous Scintillator With Pixellated Photodetector, G. J. Takacs, Anatoly B. Rosenfeld, M. L. Lerch, S. W. Lindsay, G. N. Taylor, S. R. Meikle, S. Eberl, V. L. Perevertailo
Faculty of Engineering - Papers (Archive)
Presents results of simulations performed as part of the development of a gamma-ray detector module comprising a non-pixellated scintillator and pixellated photodiode detector. The simulations have been carried out to determine the effect of surface treatment and dimensions of the scintillator on the ability to determine to 2-D position of interaction. A set of 32 different combinations of surface treatments have been considered for each crystal size. Scintillator dimensions considered have been 25 mm×25 mm×(3-6 mm). For scintillator thicknesses at the low end of this range, an average accuracy of 0.5 to 0.6 mm is achievable for many different surface …
Spectral Characterisation Of A Blue-Enhanced Silicon Photodetector, M. L. Lerch, Anatoly B. Rosenfeld, Philip E. Simmonds, G. N. Taylor, S. R. Meikle, V. L. Perevertailo
Spectral Characterisation Of A Blue-Enhanced Silicon Photodetector, M. L. Lerch, Anatoly B. Rosenfeld, Philip E. Simmonds, G. N. Taylor, S. R. Meikle, V. L. Perevertailo
Faculty of Engineering - Papers (Archive)
In this work we report on spectral response data and gamma ray spectroscopy measurements using two newly developed silicon photodetectors that are designed to have enhanced sensitivity in the blue spectral region. The enhanced sensitivity is a result of our newly developed ion implantation profile used to create the active area of the photodetector. The quantum efficiency of the new photodetectors (without any optimised antireflective coating) has been measured to be ~40% at a wavelength of 420 nm. Gamma ray spectroscopy experiments have been performed using a CsI(Tl) and a LSO crystal excited by a 137Cs or 22Na source and …
Improved Spatial Resolution By Mosfet Dosimetry Of An X-Ray Microbeam, G. I. Kaplan, Anatoly B. Rosenfeld, B. J. Allen, J. T. Booth, M. G. Carolan, A. Holmes-Siedle
Improved Spatial Resolution By Mosfet Dosimetry Of An X-Ray Microbeam, G. I. Kaplan, Anatoly B. Rosenfeld, B. J. Allen, J. T. Booth, M. G. Carolan, A. Holmes-Siedle
Faculty of Engineering - Papers (Archive)
Measurement of the lateral profile of the dose distribution across a narrow x-ray microbeam requires a dosimeter with a micron resolution. We investigated the use of a MOSFET dosimeter in an ‘‘edge-on’’ orientation with the gate insulating oxide layer parallel to the direction of the beam. We compared results using this technique to Gafchromic film measurements of a 200 micrometer wide planar x-ray microbeam. The microbeam was obtained by using a vernier micrometerdriven miniature collimator attached to a Therapax DXT300 x-ray machine operated at 100 kVp . The ‘‘edge-on’’ application allows utilization of the ultra thin sensitive volume of the …
Measurement Of Radiotherapy X-Ray Skin Dose On A Chest Wall Phantom, K. Y. Quach, J. Morales, Martin Butson, Anatoly B. Rosenfeld, Peter E. Metcalfe
Measurement Of Radiotherapy X-Ray Skin Dose On A Chest Wall Phantom, K. Y. Quach, J. Morales, Martin Butson, Anatoly B. Rosenfeld, Peter E. Metcalfe
Faculty of Engineering - Papers (Archive)
Sufficient skin dose needs to be delivered by a radiotherapy chest wall treatment regimen to ensure the probability of a near surface tumor recurrence is minimized. To simulate a chest wall treatment a hemicylindrical solid water phantom of 7.5 cm radius was irradiated with 6 MV x-rays using 20×20 cm2 and 10×20 cm2 fields at 100 cm source surface distance (SSD) to the base of the phantom. A surface dose profile was obtained from 0 to 180°, in 10° increments around the circumference of the phantom. Dosimetry results obtained from radiochromic film (effective depth of 0.17 mm) were …
Electrochemical Characterization Of Single-Walled Carbon Nanotube Electrodes, J. N. Barisci, G G. Wallace, R. H. Baughman
Electrochemical Characterization Of Single-Walled Carbon Nanotube Electrodes, J. N. Barisci, G G. Wallace, R. H. Baughman
Faculty of Engineering - Papers (Archive)
The cyclic voltammetric responses and capacitive behavior of single-walled carbon nanotube sheets or papers are described. Broad redox responses have been observed in aqueous solutions that are probably due to the presence of oxygen-containing groups bound to the surface of the nanotubes or to the impurities produced during nanotube purification. The voltammetry and capacitance of the nanotube paper do not vary significantly when the chemical nature of the electrolyte ions is changed. In nonaqueous media, no redox responses are produced except in solutions of Li1, where an intense reduction response, possibly due to lithium insertion into the nanotube bundles, is …
Synthesis Of Nonstoichiometric Amorphous Mg-Based Alloy Electrodes By Mechanical Milling, L. Sun, Hua-Kun Liu, D. H. Bradhurst, S. X. Dou
Synthesis Of Nonstoichiometric Amorphous Mg-Based Alloy Electrodes By Mechanical Milling, L. Sun, Hua-Kun Liu, D. H. Bradhurst, S. X. Dou
Faculty of Engineering - Papers (Archive)
Nonstoichiometric amorphous Mg-Ni and Mg-Ni-V alloys were synthesized by mechanical milling the crystalline Mg2Ni alloy with Ni and/or V powders. All the nonstoichiometric amorphous Mg-based alloys result in Mg-based alloy electrodes with very high discharge capacities by comparison with crystalline Mg2Ni alloys. The results indicate that nonstoichiometric amorphous Mg-based alloys can be obtained either by increasing the Ni content, adding a range of other elements, or both, using a mechanical milling method. The nonstoichiometric Mg-based alloy electrodes studied have shown improved initial discharge capacities compared with the stoichiometric amorphous MgNi alloy. These results describe a method of achieving better Mg-based …
Measurement Of Rotary Valve Air Leakage In A Pneumatic Conveying System, D. B. Hastie, Peter W. Wypych, D. M. Cook, I. Frew
Measurement Of Rotary Valve Air Leakage In A Pneumatic Conveying System, D. B. Hastie, Peter W. Wypych, D. M. Cook, I. Frew
Faculty of Engineering - Papers (Archive)
This paper explains the procedure used to determine the amount of air leakage being generated from the use of a drop-through rotary valve in a full-scale pneumatic conveying system. When producing a set ofpneumatic conveying characteristics for a test program, rotary valve air leakage is often not considered. In reality, the air mass flowrate in the conveying line will be less than the total supplied air mass flowrate due to air leakage through the rotary valve. By measuring the air leakage and adjusting the total supplied air mass flowrate to represent the actual air mass flowrate travelling through the conveying …
Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith
Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith
Faculty of Engineering - Papers (Archive)
In two-phase flow within a rock mass, where both air and water phases flow together, the accurate flow measurement of each individual phase is important in numerical analyses. The increased quantity of water phase decreases the relative permeability of the air phase, and vice versa. The relative permeability is important to analyse the risk of groundwater inundation and gas outbursts particularly in underground excavations. Two-phase flow (i.e., water and air) behaviour through naturally and artificially fractured standard rock cores is investigated using the high-pressure triaxial equipment developed by the authors. Findings of this study show that the individual flow rate …
Modeling Of Acid Generation In Pyritic Estuarine Soils, Buddhima Indraratna, Bruce G Blunden
Modeling Of Acid Generation In Pyritic Estuarine Soils, Buddhima Indraratna, Bruce G Blunden
Faculty of Engineering - Papers (Archive)
The effective management of acid sulfate or pyritic soils is a major issue for many coastal regions in Australia. Drainage and subsequent aeration of potential acid sulfate soils often leads to pyrite oxidation and the acidification of the soil and groundwater. A numerical model has been developed to calculate the rate and magnitude of pyrite oxidation in acid sulfate soils, and the distribution of oxidation products such as H+, SO4 2- and Fe3+ within the soil profile. The pyrite oxidation model includes vertical diffusion of oxygen from the atmosphere through soil macropores, lateral diffusion of dissolved oxygen from the macropores …
Modeling Of Bolted Joint Behaviour Under Constant Normal Stiffness Conditions - Laboratory Study, Buddhima Indraratna, Najdat I. Aziz, A Dey
Modeling Of Bolted Joint Behaviour Under Constant Normal Stiffness Conditions - Laboratory Study, Buddhima Indraratna, Najdat I. Aziz, A Dey
Faculty of Engineering - Papers (Archive)
The shear behaviour of grouted joints has been studied in the recent past using the conventional direct shear apparatus, where the normal load on the joint plane is kept constant during testing. The Constant Normal Stiffness (CNS) condition is adopted in this study of shear behaviour of bolted joints, as the CNS condition represents a better approximation of the deformation behaviour of grouted joints in underground excavations as compared to the conventional Constant Normal Load (CNL) condition. A series of tests were conducted to study the behaviour of these stabilised joints under constant normal stiffness condition at an initial normal …
Predicted And Observed Behaviour Of Soft Clay Foundations Stabilised With Vertical Drains, Buddhima Indraratna, Wadud Salim, I W Redana
Predicted And Observed Behaviour Of Soft Clay Foundations Stabilised With Vertical Drains, Buddhima Indraratna, Wadud Salim, I W Redana
Faculty of Engineering - Papers (Archive)
A novel plane strain approach is introduced to model the behaviour of embankment foundations on soft clay stabilised with vertical drains, where the classical axisymmetric solutions are converted to an equivalent plane strain model, incorporating the effects of smear and well resistance. This paper describes the behaviour of an embankment stabilised with vertical drains, where a specific case history is selected from Malaysia. The consolidation of soft clay is modelled on the basis of the modified Cam-clay. The settlement behaviour at various stages of embankment loading is analysed using the finite element technique, and the numerical results are compared with …
State Of The Art Large Scale Testing Of Ballast, Buddhima Indraratna, D J Ionescu
State Of The Art Large Scale Testing Of Ballast, Buddhima Indraratna, D J Ionescu
Faculty of Engineering - Papers (Archive)
Poor performance of rail roads is often associated with the loss of cross level, track profile and track alignment. The initial as placed condition of ballast and its engineering behaviour govern the stability and the performance of a railway track. The load bearing capacity of ballast and its short and long term degradation characteristics can only be studied using large scale testing equipment, because the conventional geotechnical equipment cannot accommodate the relatively large aggregates. Large-scale testing provides specific geotechnical knowledge on the shear strength and particle degradation of ballast, in relation to the particle size distribution. The influence of principal …
Two 1-Substituted 4-Nitroimidazoles, Maciej Kubicki, Teresa Borowiak, Jerzy Suwinski, Pawel Wagner
Two 1-Substituted 4-Nitroimidazoles, Maciej Kubicki, Teresa Borowiak, Jerzy Suwinski, Pawel Wagner
Australian Institute for Innovative Materials - Papers
Crystalline 4-nitro-1-phenylimidazole, C9H7N3O2, (I), and 4′-nitro-1-phenyl-4,1′-biiimidazole, C12H9N5O2, (II), contain C—H⃛O and C—H⃛N hydrogen bonds, connecting the molecules into infinite chains. The aromatic fragments in both compounds are nearly planar. The dihedral angles between the benzene and imidazole rings are 26.78 (5)° in (I) and 29.36 (8)° in (II).
Population Inversion In An Optically Pumped Single Quantum Well, Timoghy J. Green, Wen Xu
Population Inversion In An Optically Pumped Single Quantum Well, Timoghy J. Green, Wen Xu
Australian Institute for Innovative Materials - Papers
An optically pumped intersubband laser generator is proposed in which the continuum states above an Al0.2Ga0.8As–GaAs–Al0.2Ga0.8As single quantum well with a width of L=17 nm serve as the highest level in a four-level laser system. The design allows much greater flexibility in the choice of pumping source and simplifies considerably the device fabrication. We have obtained the electronic subband structure of the proposed device and utilized a simple rate equation approach to examine the electron density in different states under optical pumping.
Microscopic Treatment Of Substrate Effects On Linear And Quadratic Optical Response Of Model Langmuir-Blodgett Multilayers, Marc In Het Panhuis, R W. Munn
Microscopic Treatment Of Substrate Effects On Linear And Quadratic Optical Response Of Model Langmuir-Blodgett Multilayers, Marc In Het Panhuis, R W. Munn
Australian Institute for Innovative Materials - Papers
Microscopic calculations are reported of linear and quadratic nonlinear optical response in model Langmuir-Blodgett films on a substrate, which is treated by the method of images. The effect of the substrate is significant in the first two layers, and is greatest for tilted molecules with their head groups adjacent to the substrate. The main qualitative effect is to lower the symmetry relative to a free-standing film. Calculations for stearic acidfilms show that the substrate effect is most important for molecules with nonuniform response on a metallic substrate.
Microscopic Calculations Of Linear And Quadratic Optical Response In Model Langmuir-Blodgett Multilayers, Marc In Het Panhuis, R W. Munn
Microscopic Calculations Of Linear And Quadratic Optical Response In Model Langmuir-Blodgett Multilayers, Marc In Het Panhuis, R W. Munn
Australian Institute for Innovative Materials - Papers
Microscopic calculations are reported of linear and quadratic nonlinear optical response in Langmuir–Blodgett films. The films are modeled as ordered layers of molecules that can tilt from the vertical and have a higher polarizability and first hyperpolarizability in the head than in the tail. The local electric field varies little after the first layer and negligibly after the second, which simplifies the analysis. Tilted two-layer Y-type films can have quadratic susceptibility components as large as X- or Z-type ones. Overall the results provide a systematic account of the linear and nonlinear optical properties as a function of …
Asymmetry And Rectification In The Tunnel Current Of A Nanometer-Sized Metal-Conjugated Polymer-Metal Junction, S T. Yau, C Zhang, Peter Innis
Asymmetry And Rectification In The Tunnel Current Of A Nanometer-Sized Metal-Conjugated Polymer-Metal Junction, S T. Yau, C Zhang, Peter Innis
Australian Institute for Innovative Materials - Papers
Electron transport processes of a nanometer metal-conjugated polymer–metal tunnel junction have been probed using a scanning tunneling microscope. The tunnel current of the junction shows two effects. The appearance of an asymmetry in the tunnel current indicates that the junction transport mechanism is different from that for which tunneling occurs directly between two metallic electrodes. Thus, understanding of the asymmetry and hence the transport mechanism demands a detailed description of the metal–polymer interface. By applying the theories of the metal–semiconductor interface to the tunnel junction, we show the presence of an asymmetric electrostatic potential-energy profile, which, together with the metal-induced …
Fair On-Line Gambling, Weiliang Zhao, Vijay Varadharajan, Yi Mu
Fair On-Line Gambling, Weiliang Zhao, Vijay Varadharajan, Yi Mu
Faculty of Engineering - Papers (Archive)
This paper proposes a fair electronic gambling scheme for the Internet. The proposed scheme provides a unique link between payment and gambling outcome so that the winner can be ensured to get the payment. Since an optimal fair exchange method is used in gambling message exchange, the proposed system guarantees that no one can successfully cheat during a gambling process. Our system requires an off-line Trusted Third Party (TTP). If a cheating occurs, the TTP can resolve the problem and make the gambling process fair
Toward A Heuristic Optimum Design Of Rolling Schedules For Tandem Cold Rolling Mills, Dadong Wang, A Kiet Tieu, Friso Deboer, B Ma, W. Y. Daniel Yuen
Toward A Heuristic Optimum Design Of Rolling Schedules For Tandem Cold Rolling Mills, Dadong Wang, A Kiet Tieu, Friso Deboer, B Ma, W. Y. Daniel Yuen
Faculty of Engineering and Information Sciences - Papers: Part A
Scheduling for tandem cold mills refers to the determination of inter-stand gauges, tensions and speeds of a specified product. Optimal schedules should result in maximized throughput and minimized operating cost. This paper presents a genetic algorithm based optimization procedure for the scheduling of tandem cold rolling mills. The optimization procedure initiates searching from a logical staring point - an empirical rolling schedule - and ends with an optimum cost. Cost functions are constructed to heuristically direct the genetic algorithm's searching, based on the consideration of power distribution, tension, strip flatness and rolling constraints. Numerical experiments have shown that the proposed …