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Full-Text Articles in Engineering
Response Function Of A Two-Dimensional Electron Gas In A Unidirectional Periodic Potential , S. M. Stewart, C. Zhang
Response Function Of A Two-Dimensional Electron Gas In A Unidirectional Periodic Potential , S. M. Stewart, C. Zhang
Faculty of Engineering - Papers (Archive)
The dynamical density-response function of a periodically modulated two-dimensional electron gas under a perpendicular magnetic field is calculated within the random-phase approximation. It is found that the response function is not only broadened by the periodic potential, it also contains a series of subsingularities at the band edges. The maximum number of subsingularities is 2nmax, where nmax is the number of occupied Landau leveles (the last level may be partially filled). It is further proposed that light-scattering or electromagnetic absorption experiments can be performed to study these predicted structures.
Magnetoplasmon Emission Versus Landau-Level Scattering In Resonant Tunneling Through Double-Barrier Structures , C. Zhang, D. J. Fisher
Magnetoplasmon Emission Versus Landau-Level Scattering In Resonant Tunneling Through Double-Barrier Structures , C. Zhang, D. J. Fisher
Faculty of Engineering - Papers (Archive)
We consider electron tunneling in a parallel magnetic field taking into account the electron-electron interaction. It is shown that a self-consistent treatment of the dynamical electron-electron interaction in resonant tunneling can lead to the proposed plasmon assisted resonant tunneling. Such magnetoplasmon assisted resonant tunneling gives rise to satellite peaks or shoulders in the tunneling current. At low temperatures, only magnetoplasmon emission processes contribute and satellites only appear on the high bias side of the main resonance. The mechanism proposed here may be used to study the magnetotunneling in high-mobility systems where disorder is at minimum.
The Influence Of Heavy Water On Boron Requirements For Neutron Capture Therapy, S. A. Wallace, J. N. Mathur, B. J. Allen
The Influence Of Heavy Water On Boron Requirements For Neutron Capture Therapy, S. A. Wallace, J. N. Mathur, B. J. Allen
Faculty of Engineering - Papers (Archive)
Neutron penetration in tissue is a major limitation of thermal NCT, as such much work has centred upon the epithermal neutron beam in an effort to improve this situation. Further gains in neutron flux penetration, and thus therapeutic ratios, are possible if natural water is replaced with heavy water prior to therapy. Applying MCNP to heterogeneous ellopsoidal skull/brain model, advantage depth and therapeutic depth parameters are studied as a function of heavy water replacement for a range of tumor to blood boron ratios.
Theory Of Photoluminescence Of Magnetopolarons In Quantum Wells Containing High Densities Of Electrons , L. Swierkowski, J. Szymanski, Philip E. Simmonds, T. A. Fisher, M. S. Skolnick
Theory Of Photoluminescence Of Magnetopolarons In Quantum Wells Containing High Densities Of Electrons , L. Swierkowski, J. Szymanski, Philip E. Simmonds, T. A. Fisher, M. S. Skolnick
Faculty of Engineering - Papers (Archive)
We present a theory of photoluminescence in the presence of a quantizing magnetic field for a quasi-two-dimensional electron gas interacting with the lattice assuming a weak Fröhlich interaction with bulk longitudinal optical (LO) phonons. Unlike in the conventional cyclotron resonance, the calculated photoluminescence spectrum for high electron concentrations exhibits strong renormalization due to the resonant electron-phonon coupling between two quasiholes in conduction Landau levels whenever the LO-phonon energy is close to the energy difference between any two occupied Landau levels. The high electron concentration is necessary to push the Fermi energy well above that of LO phonons. The screening of …
Magneto-Optical Probe Of The Two-Dimensional Hole-System Low-Temperature Ground States, A. G. Davies, E. E. Mitchell, R G. Clark, Philip E. Simmonds, D. A. Ritchie, D. Y. Simmons, M. Pepper, G. A. Jones
Magneto-Optical Probe Of The Two-Dimensional Hole-System Low-Temperature Ground States, A. G. Davies, E. E. Mitchell, R G. Clark, Philip E. Simmonds, D. A. Ritchie, D. Y. Simmons, M. Pepper, G. A. Jones
Faculty of Engineering - Papers (Archive)
Band-gap magnetophotoluminescence (PL) has been used to study a high-quality, low-density p-type GaAs-AlxGa1-xAs single quantum well at millikelvin temperatures. Two PL lines associated with recombination in the quantum well are observed. The lower-energy line, present over the entire field range, displays intensity minima at integer quantum Hall states and a marked intensity falloff to a minimum value as the Landau-level filling factor is reduced to ν=1/3. The higher-energy line emerges in the extreme quantum regime ν
Large-Scale, Radial Drainage Consolidometer With Central Drain Facility, Buddhima Indraratna, I. Redana
Large-Scale, Radial Drainage Consolidometer With Central Drain Facility, Buddhima Indraratna, I. Redana
Faculty of Engineering - Papers (Archive)
A large scale radial draining consolidometer at the University of Wollongong will be used to study the consolidation and drainage properties of saturated or "wet" materials. A description of the device is given.
Comparison Of Two Methods For Detection Of Cryptosporidium & Giardia In Water, Eva C. Nieminski, Frank W. Schaefer Iii, Jerry E. Ongerth
Comparison Of Two Methods For Detection Of Cryptosporidium & Giardia In Water, Eva C. Nieminski, Frank W. Schaefer Iii, Jerry E. Ongerth
Faculty of Engineering and Information Sciences - Papers: Part A
The steps of two immunofluorescent-antibody-based detection methods were evaluated for their efficiencies in detecting Giardia cysts and Cryptosporidium oocysts. The two methods evaluated were the American Society for Testing and Materials proposed test method for Giardia cysts and Cryptosporidium oocysts in low-turbidity water and a procedure employing sampling by membrane filtration, Percoll-Percoll step gradient, and immunofluorescent staining. The membrane filter sampling method was characterized by higher recovery rates in all three types of waters tested: raw surface water, partially treated water from a flocculation basin, and filtered water. Cyst and oocyst recovery efficiencies decreased with increasing water turbidity regardless of …
Molecular Epidemiology Of A Fast-Food Restaurant-Associated Outbreak Of Escherichia Coli O157:H7 In Washington State, Linda M. Grimm, Marcia Goldoft, John Kobayashi, Jay H. Lewis, Dalia Alfi, Ann Marie Perdichizzi, Phillip I. Tarr, Jerry E. Ongerth, Steve L. Moseley, Mansour Samadpour
Molecular Epidemiology Of A Fast-Food Restaurant-Associated Outbreak Of Escherichia Coli O157:H7 In Washington State, Linda M. Grimm, Marcia Goldoft, John Kobayashi, Jay H. Lewis, Dalia Alfi, Ann Marie Perdichizzi, Phillip I. Tarr, Jerry E. Ongerth, Steve L. Moseley, Mansour Samadpour
Faculty of Engineering and Information Sciences - Papers: Part A
We studied the molecular epidemiology of the recent fast-food restaurant chain-associated Escherichia coli O157:H7 outbreak in Washington State. Genomic DNAs prepared from strains isolated from 433 patients were probed with radiolabelled Shiga-like toxin (SLT) I and SLT II genes and bacteriophage l DNA and were subsequently analyzed for their restriction fragment length polymorphism (RFLP) patterns. The SLT RFLP and l RFLP profiles of an E. coli O157:H7 strain isolated from the incriminated beef and prototype patient were compared with those of the patient isolates for determination of the concordance between patterns. Of the 377 patients with primary and secondary cases …
Mine Boundary Detection Using Markov Random Field Models, Xia Hua, Jennifer L. Davidson, Noel A. Cressie
Mine Boundary Detection Using Markov Random Field Models, Xia Hua, Jennifer L. Davidson, Noel A. Cressie
Faculty of Engineering and Information Sciences - Papers: Part A
Detection of objects in images in an automated fashion is necessary for many applications, including automated target recognition. In this paper, we present results of boundary detection using Markov random fields. Once the boundaries of regions are detected, object recognition can be conducted to classify the regions within the boundaries. Thus, an approach that gives good boundary detection is very important in many automated target recognition systems. Our algorithm for boundary detection combines a Bayesian approach with a histogram specification technique to locate edges of objects that have a closed-loop boundary. The boundary image is modeled by a Markov random …
The Formation Of Ternary Compound Fe3mo3c By Ball Milling, L M. Di, Andrzej Calka, Z L. Li, J S. Williams
The Formation Of Ternary Compound Fe3mo3c By Ball Milling, L M. Di, Andrzej Calka, Z L. Li, J S. Williams
Faculty of Engineering and Information Sciences - Papers: Part A
Ball milling of Mo in nitrogen and ammonia gases has been studied. After heating, the formation of an intriguing ternary compound, Fe3Mo3C1−x , was observed as a result of Fe (and C) contamination from the milling apparatus. For a comparison, mechanical alloying of Fe–Mo–C powders with a stoichiometric composition of Fe3Mo3C was also performed and again an Fe–Mo–C alloy was obtained after milling.Thermal analysis shows a single transition peak for the formation of both the Fe3Mo3C phase in the latter case and also for Fe3 …
Extending Multipliers From Semigroups, Marcelo Laca, Iain Raeburn
Extending Multipliers From Semigroups, Marcelo Laca, Iain Raeburn
Faculty of Engineering and Information Sciences - Papers: Part A
A multiplier on a normal subsemigroup of a group can be extended to a multiplier on the group. This is used to show that normal cancellative semigroups have the same second cohomology as the group they generate, generalising earlier results of Arveson, Chernoff, and Dinh. The main tool is a dilation theorem for isometric multiplier representations of semigroups.
Induced C*-Algebras And Landstad Duality For Twisted Coactions, John C. Quigg, Iain Raeburn
Induced C*-Algebras And Landstad Duality For Twisted Coactions, John C. Quigg, Iain Raeburn
Faculty of Engineering and Information Sciences - Papers: Part A
No abstract provided.
A Simplified Form Of Condensed Detachment, M W. Bunder
A Simplified Form Of Condensed Detachment, M W. Bunder
Faculty of Engineering and Information Sciences - Papers: Part A
This paper gives a simple, elegant statement of the condensed detachment rule that is independent of most general unifiers and proves that this is equivalent to the longer, more usual, formulation.
Piezospectroscopy Of The P3/2 And Fano Series Of Singly Ionised Zn In Ge, Gejin Piao, Peter Fisher, R A. Lewis
Piezospectroscopy Of The P3/2 And Fano Series Of Singly Ionised Zn In Ge, Gejin Piao, Peter Fisher, R A. Lewis
Faculty of Engineering and Information Sciences - Papers: Part B
Abstract presented at the Sixth International Conference on Shallow Level Centers in Semiconductors, 10-12 August 1994, Berkeley, United States