26,092 research outputs found

    Observation of the single-electron regime in a highly tunable silicon quantum dot

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    We report on low-temperature electronic transport measurements of a silicon metal-oxide-semiconductor quantum dot, with independent gate control of electron densities in the leads and the quantum dot island. This architecture allows the dot energy levels to be probed without affecting the electron density in the leads, and vice versa. Appropriate gate biasing enables the dot occupancy to be reduced to the single-electron level, as evidenced by magnetospectroscopy measurements of the ground state of the first two charge transitions. Independent gate control of the electron reservoirs also enables discrimination between excited states of the dot and density of states modulations in the leads.Comment: 4 pages, 3 figures, accepted for Applied Physics Letter

    Effects Of Post-Deposition Annealing Temperature And Time On Physical Properties Of Metal-Organic Decomposed Lanthanum Cerium Oxide Thin Film.

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    Lanthanum cerium oxide (LaxCeyOz) precursor was prepared using metal-organic decomposition method. The effects of post-deposition annealing temperatures (400-1000 °C) and annealing time (15-120 minutes) in argon ambient on physical properties of the deposited film were investigated

    Clinical translation of [18F]ICMT-11 for measuring chemotherapy-induced caspase 3/7 activation in breast and lung cancer

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    Background: Effective anticancer therapy is thought to involve induction of tumour cell death through apoptosis and/or necrosis. [18F]ICMT-11, an isatin sulfonamide caspase-3/7-specific radiotracer, has been developed for PET imaging and shown to have favourable dosimetry, safety, and biodistribution. We report the translation of [18F]ICMT-11 PET to measure chemotherapy-induced caspase-3/7 activation in breast and lung cancer patients receiving first-line therapy. Results: Breast tumour SUVmax of [18F]ICMT-11 was low at baseline and unchanged following therapy. Measurement of M30/M60 cytokeratin-18 cleavage products showed that therapy was predominantly not apoptosis in nature. While increases in caspase-3 staining on breast histology were seen, post-treatment caspase-3 positivity values were only approximately 1%; this low level of caspase-3 could have limited sensitive detection by [18F]ICMT-11-PET. Fourteen out of 15 breast cancer patients responded to first–line chemotherapy (complete or partial response); one patient had stable disease. Four patients showed increases in regions of high tumour [18F]ICMT-11 intensity on voxel-wise analysis of tumour data (classed as PADS); response was not exclusive to patients with this phenotype. In patients with lung cancer, multi-parametric [18F]ICMT-11 PET and MRI (diffusion-weighted- and dynamic contrast enhanced-MRI) showed that PET changes were concordant with cell death in the absence of significant perfusion changes. Conclusion: This study highlights the potential use of [18F]ICMT-11 PET as a promising candidate for non-invasive imaging of caspase3/7 activation, and the difficulties encountered in assessing early-treatment responses. We summarize that tumour response could occur in the absence of predominant chemotherapy-induced caspase-3/7 activation measured non-invasively across entire tumour lesions in patients with breast and lung cancer

    Influence of blade aerodynamic model on prediction of helicopter rotor aeroacoustic signatures

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    Brown’s vorticity transport model has been used to investigate how the local blade aerodynamic model influences the quality of the prediction of the high-frequency airloads associated with blade–vortex interactions, and thus the accuracy with which the acoustic signature of a helicopter rotor can be predicted. The vorticity transport model can accurately resolve the structure of the wake of the rotor and allows significant flexibility in the way that the blade loading can be represented. The Second Higher-Harmonic Control Aeroacoustics Rotor Test was initiated to provide experimental insight into the acoustic signature of a rotor in cases of strong blade–vortex interaction. Predictions of two models for the local blade aerodynamics are compared with the test data. A marked improvement in accuracy of the predicted high-frequency airloads and acoustic signature is obtained when a lifting-chord model for the blade aerodynamics is used instead of a lifting-line-type approach. Errors in the amplitude and phase of the acoustic peaks are reduced, and the quality of the prediction is affected to a lesser extent by the computational resolution of the wake, with the lifting-chord model producing the best representation of the distribution of sound pressure below the rotor

    Entanglement and statistics in Hong-Ou-Mandel interferometry

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    Hong-Ou-Mandel interferometry allows one to detect the presence of entanglement in two-photon input states. The same result holds for two-particles input states which obey to Fermionic statistics. In the latter case however anti-bouncing introduces qualitative differences in the interferometer response. This effect is analyzed in a Gedankenexperiment where the particles entering the interferometer are assumed to belong to a one-parameter family of quons which continuously interpolate between the Bosonic and Fermionic statistics.Comment: 7 pages, 3 figures; minor editorial changes and new references adde

    Comparative Distribution of System Losses to Market Participants Using Different Loss Allocation Methods

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    A key part of electricity pricing is the fair and equitable allocation of system losses. This paper critically compares several existing loss allocation methods. The methods addressed include existing approaches such as pro rata method, proportional sharing method [1], loss formula [2], and incremental method [3], in addition to a new method proposed by the authors, which allocates losses from a loop-based representation of system behaviour. The distinct numerical allocation of losses in both the IEEE 14-bus network and a modified Nordic 41 bus system is listed for comparison. The similarity between the different loss allocations methods varies considerably, depending upon the system to which the methods are applied. This is primarily a result of the manner in which the different allocation methods address the impact of network structure. Further work is still required to determine which method encourages better system operation

    Comparative effectiveness of loss allocation methods for providing signals to affect market operation

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    The distribution of system losses, an integral part of electricity pricing, can play an important role in the operation of electricity markets. To date, despite the existence of many loss allocation methods, no one method is commonly used in established electricity markets. Furthermore, some markets are still considering using different methods that will provide more efficient treatment of losses and aid in improving market operations and structures. This paper compares the loss allocation methods used in existing markets in Eastern Australia and Great Britain, as well as with the pro rata and proportional sharing approaches. Through implementation of the loss allocation methods on the CIGRE Nordic 32 bus system we examine what behaviour each method encourages. Results suggest that the method used in the Australian market provides the most sophisticated signal to market participants. Similar results, however, can be obtained using the simpler approach taken in Great Britain. This reinforces that the selection of loss allocation will be a market dependent problem
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