944 resultados para Ultra-high energies


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Dabie shan lies between Northchina crust and Yangzi crust, which is the result of the collisional orogenen in Triassic period. The biggest area of UHP metamorphic zone have been found in Dabie Shan, which have been verified formed during the course of collision and extrusion after orogenic activity. The Dabie shan is divisioned into four parts, which are North Huaiyang metamorphic zone, North Dabie complex zone, South Dabie ultra-high pressure metamorphic zone and Susong metamorphic zone. Extension structure of late Mesozoic is the key to explain the intrusion and outcrop of UHP metamorphic rocks in Dabie Shan. During the course of structure evolution of the Dabie shan in late Mesozoic period, Luotian dome was formed with the old gneiss lifting from the core of the Dabie shan. There are four enormous ductile zone circled Luotian dorm. Xiaotian-mozitan shear zone is the limit of North Huaiyang metamorphic zone and North Dabie complex zone; Shuihou-wuhe shear zone is the limit of North Dabie complex zone and South Dabie ultra-high pressure metamorphic zone; Taihu-mamiao shears zone is the limit of South Dabie ultra-high pressure metamorphic zone and Susong metamorphic zone and Susong-Qingshuihe shear zone is the south limit of Susong metamorphic zone; the old stress at Dabie shan in late Mesozoic was about 90MPa through the experiment of transmission electricity microscope. The main four ductile shear zone of Dabie shan all have the characteristic of detachment, Xiaotian-mozitan shear zone detached to NNE, the detachment direction of Shuihou-wuhe shear zone and Taihu-mamiao shears zone is SSE, and Susong-Qingshuihe shear zone is SW. The finite strain measurement show that Xiaotian-mozitan shear zone have experienced detachment which was more than 50km, and the detachment of Susong-Qingshuihe shear zone was more than 12km in late Mesozoic; the Flin parameter of Shuihou-wuhe shear zone is much smaller than 1(0.01-0.1), which show that this shear zone was squeezed when it was formed and the initiative function of Luotian granite intrusion during the course of detachment. The Flin parameter of Taihu-mamiao shears zone is above 1(1.1) and Susong-Qingshuihe shear zone is much more than 1(7.6), which show that they are formed in the state of extension at the beginning. These all Flin parameter imply a transition from pure shear to simple shear of the south three shear zone circling Luotian dome from north to south. The rock group analysis show that the rocks inside shear zone encountered middle or high temperature metamorphic activity. The single mineral ~(40)Ar/~(39)Ar age of the main shear zone at Dabie shan show that the three shear zone north to Luotian dome were formed about 190Ma.Taihu-mamiao shear zone was the earliest, Susong shear zone was later than former, and Shuihou-wuhe sheanaone was the latest. They were all the chanel of returning of UHP metamorphic rocks, so they all representative the returning age of UHP metamorphic rocks. The final outcrop of these UHP metamorphic rocks was due to the detachment aroused by the enormous magma intrusion. The biotite age of deformed rocks in Susong-Qingshuihe shear zone is in average 126Ma, and the age of Xiaotian-mozitan is about 125Ma, which is in the same time or a little later than magma intrusion of Luotian dome, and imply that granite intrusion of late Mesozoic in Dabie orogenen is the reason of the detachment.

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As far as the architecture of the south Dabie metamorphic terrain is concerned, there have been lots of different opinions for a long time. Wang et al. (1990, 1992) thought of it was a continuous terrain. Okay (1993) held that it consistes of two different tectonic terrains: the 'hot' and 'cold' eclogite belt. Liu and Wang (1998) held that it is composed of different metamorphic blocks through 'melange' in depth. For this reason, we have choiced Hualiangting reservoir of Taihu county as the study area treat eclogite as the investigated objection in this thesis, and employ the detailed 1 :10000 geological mapping, methods of Petrography and electonic probe anaylsis to probe into the architecture of the south Dabie metamorphic terrains. In the light of the eclogite occurrenc in the field, the analysis of Petrography, the research on metamoiphic P-T path and condition of the peak metamorphic P-T condition, the eclogite in the Taihu area of Dabieshan have been classified into three types eclogite from the south to the north: The zhujiachong type eclogite; The Daba type eclogite; (3) The Jinheqiao type eclogite, their mineral composition, structure, and mineral component vary continuously. These eclogites have the same rnetamoiphic stages, P-T evolution pattern, and their peak P-T condition varies continuously. The zhujiachong type eclogite is formed in the high pressure metamoiphic environment. The Jinheqiao type eclogite is formed in the typical ultra-high pressure environment. The Daba type eclogite is formed in the transformed metamorphic environment between high pressure and ultra-high pressure metamorphism. All these evidences show that the south Dabie metamorphic terrain is a continuous metamorphic block and no large fault ever existed.

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The development of ultra high speed (~20 Gsamples/s) analogue to digital converters (ADCs), and the delayed deployment of 40 Gbit/s transmission due to the economic downturn, has stimulated the investigation of digital signal processing (DSP) techniques for compensation of optical transmission impairments. In the future, DSP will offer an entire suite of tools to compensate for optical impairments and facilitate the use of advanced modulation formats. Chromatic dispersion is a very significant impairment for high speed optical transmission. This thesis investigates a novel electronic method of dispersion compensation which allows for cost-effective accurate detection of the amplitude and phase of the optical field into the radio frequency domain. The first electronic dispersion compensation (EDC) schemes accessed only the amplitude information using square law detection and achieved an increase in transmission distances. This thesis presents a method by using a frequency sensitive filter to estimate the phase of the received optical field and, in conjunction with the amplitude information, the entire field can be digitised using ADCs. This allows DSP technologies to take the next step in optical communications without requiring complex coherent detection. This is of particular of interest in metropolitan area networks. The full-field receiver investigated requires only an additional asymmetrical Mach-Zehnder interferometer and balanced photodiode to achieve a 50% increase in EDC reach compared to amplitude only detection.

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Integrated nanowire electrodes that permit direct, sensitive and rapid electrochemical based detection of chemical and biological species are a powerful emerging class of sensor devices. As critical dimensions of the electrodes enter the nanoscale, radial analyte diffusion profiles to the electrode dominate with a corresponding enhancement in mass transport, steady-state sigmoidal voltammograms, low depletion of target molecules and faster analysis. To optimise these sensors it is necessary to fully understand the factors that influence performance limits including: electrode geometry, electrode dimensions, electrode separation distances (within nanowire arrays) and diffusional mass transport. Therefore, in this thesis, theoretical simulations of analyte diffusion occurring at a variety of electrode designs were undertaken using Comsol Multiphysics®. Sensor devices were fabricated and corresponding experiments were performed to challenge simulation results. Two approaches for the fabrication and integration of metal nanowire electrodes are presented: Template Electrodeposition and Electron-Beam Lithography. These approaches allow for the fabrication of nanowires which may be subsequently integrated at silicon chip substrates to form fully functional electrochemical devices. Simulated and experimental results were found to be in excellent agreement validating the simulation model. The electrochemical characteristics exhibited by nanowire electrodes fabricated by electronbeam lithography were directly compared against electrochemical performance of a commercial ultra-microdisc electrode. Steady-state cyclic voltammograms in ferrocenemonocarboxylic acid at single ultra-microdisc electrodes were observed at low to medium scan rates (≤ 500 mV.s-1). At nanowires, steady-state responses were observed at ultra-high scan rates (up to 50,000 mV.s-1), thus allowing for much faster analysis (20 ms). Approaches for elucidating faradaic signal without the requirement for background subtraction were also developed. Furthermore, diffusional process occurring at arrays with increasing inter-electrode distance and increasing number of nanowires were explored. Diffusion profiles existing at nanowire arrays were simulated with Comsol Multiphysics®. A range of scan rates were modelled, and experiments were undertaken at 5,000 mV.s-1 since this allows rapid data capture required for, e.g., biomedical, environmental and pharmaceutical diagnostic applications.

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The Telescope Array is a detector of extensive air shower produced by ultra High energy cosmic ray. This detector is located on Utah, USA. The construction have been completed and the full operation has been running from March 2008. In this talk, the status of observation and our prospects are described. © 2010 American Institute of Physics.

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Computer based mathematical models describing the aircraft evacuation process have a vital role to play in the design and development of safer aircraft, in the implementation of safer and more rigorous certification criteria, cabin crew training and in post mortuum accident investigation. As the risk of personal injury and costs involved in performing large-scale evacuation experiments for the next generation 'Ultra High Capacity Aircraft' (UHCA) are expected to be high, the development and use of these evacuation modelling tools may become essential if these aircraft are to prove a viable reality. In this paper the capabilities and limitations of the airEXODUS evacuation model are described. Its successful application to the prediction of a recent certification trial, prior to the actual trial taking place, is described. Also described is a newly defined parameter known as OPS which can be used as a measure of evacuation trial optimality. In addition, sample evacuation simulations in the presence of fire atmospheres are described. Finally, the data requiremnets of the airEXODUS evacuation model is discussed along with several projects currently underway at the the Univesity of Greenwich designed to obtain this data. Included in this discussion is a description of the AASK - Aircraft Accident Statistics and Knowledge - data base which contains detailed information from aircraft accident survivors.

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Computer based mathematical models describing the aircraft evacuation process have a vital role to play in the design and development of safer aircraft, in the implementation of safer and more rigorous certification criteria and in cabin crew training and post mortuum accident investigation. As the risk of personal injury and costs involved in performing large-scale evacuation experiments for the next generation `Ultra High Capacity Aircraft' (UHCA) are expected to be high, the development and use of these evacuation modelling tools may become essential if these aircraft are to prove a viable reality. This paper describes the capabilities and limitations of the airEXODUS evacuation model and some attempts at validation, including its successful application to the prediction of a recent certification trial, prior to the actual trial taking place, is described. Also described is a newly defined parameter known as OPS which can be used as a measure of evacuation trial optimality. In addition, sample evacuation simulations in the presence of fire atmospheres are described.

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Computer based mathematical models describing the aircraft evacuation process have a vital role to play in the design and development of safer aircraft, the implementation of safer and more rigorous certification criteria, in cabin crew training and post-mortem accident investigation. As the risk of personal injury and the costs involved in performing large-scale evacuation experiments for the next generation ultra high capacity aircraft (UHCA) are expected to be high, the development and use of these evacuation modelling tools may become essential if these aircraft are to prove a viable reality. This paper describes the capabilities and limitations of the airEXODUS evacuation model and some attempts at validation, including its successful application to the prediction of a recent certification trial, prior to the actual trial taking place. Also described is a newly defined performance parameter known as OPS that can be used as a measure of evacuation trial optimality. In addition, sample evacuation simulations in the presence of fire atmospheres are described.

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Computer based mathematical models describing the aircraft evacuation process have a vital role to play in the design and development of safer aircraft, in the implementation of safer and more rigorous certification criteria and in post mortuuum accident investigation. As the risk of personal injury and costs involved in performing large-scale evacuation experiments for the next generation 'Ultra High Capacity Aircraft' (UHCA) are expected to be high, the development and use of these evacuation modelling tools may become essential if these aircraft are to prove a viable reality. In this paper the capabilities and limitation of the air-EXODUS evacuation model are described. Its successful application to the prediction of a recent certificaiton trial, prior to the actual trial taking place, is described. Also described is a newly defined parameter known as OPS which can be used as a measure of evacuation trial optimality. Finally, the data requirements of aircraft evacuation models is discussed along with several projects currently underway at the University of Greenwich designed to obtain this data. Included in this discussion is a description of the AASK - Aircraft Accident Statistics and Knowledge - data base which contains detailed information from aircraft accident survivors.

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Computer based mathematical models describing aircraft fire have a role to play in the design and development of safer aircraft, in the implementation of safer and more rigorous certification criteria and in post mortuum accident investigation. As the cost involved in performing large-scale fire experiments for the next generation 'Ultra High Capacity Aircraft' (UHCA) are expected to be prohibitively high, the development and use of these modelling tools may become essential if these aircraft are to prove a safe and viable reality. By describing the present capabilities and limitations of aircraft fire models, this paper will examine the future development of these models in the areas of large scale applications through parallel computing, combustion modelling and extinguishment modelling.

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The ageing behaviour of ultra-high molecular weight polyethylene (UHMWPE) has been studied following gamma irradiation (25 or 40 kGy) in air. Accelerated ageing procedures used elevated temperature (70°C) and/or pressurised oxygen (5 bar). Shelf-aged UHMWPE was also studied. The variation in surface density and mechanical properties were determined following the various sterilisation and ageing treatments. Microabrasive wear testing was also performed. Wear rates were found to correlate well with stress at break for sterilised and aged UHMWPE but not with elongation to failure. It is proposed that the wear mechanism is fracture dominated and occurs following some disentanglement of the polymer chains. Wear also depends upon embrittlement of the surface layer due to its processing and ageing. Elongation to failure in a tensile test is not a good measure of this embrittlement whereas the microabrasion test provides more surface sensitive information concerning this property.

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Cooling of mechanical resonators is currently a popular topic in many fields of physics including ultra-high precision measurements, detection of gravitational waves and the study of the transition between classical and quantum behaviour of a mechanical system. Here we report the observation of self-cooling of a micromirror by radiation pressure inside a high-finesse optical cavity. In essence, changes in intensity in a detuned cavity, as caused by the thermal vibration of the mirror, provide the mechanism for entropy flow from the mirror's oscillatory motion to the low-entropy cavity field. The crucial coupling between radiation and mechanical motion was made possible by producing free-standing micromirrors of low mass (m approximately 400 ng), high reflectance (more than 99.6%) and high mechanical quality (Q approximately 10,000). We observe cooling of the mechanical oscillator by a factor of more than 30; that is, from room temperature to below 10 K. In addition to purely photothermal effects we identify radiation pressure as a relevant mechanism responsible for the cooling. In contrast with earlier experiments, our technique does not need any active feedback. We expect that improvements of our method will permit cooling ratios beyond 1,000 and will thus possibly enable cooling all the way down to the quantum mechanical ground state of the micromirror.

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Tissue-implanted ultra-high frequency (UHF) radio devices are being employed in both humans and animals for telemetry and telecommand applications, This paper describes the experimental measurement and electromagnetic modeling of propagation from 418-MHz and 916.5-MHz sources placed in the human vagina. Whole-body homogeneous and semi-segmented software models were constructed using data from the Visible Human Project. Bodyworn radiation efficiencies for a vaginally placed 418-MHz source were calculated using finite-difference time-domain and ranged between 1.6% and 3.4% (corresponding to net body losses of between 14.7 and 18.0 dB), Greater losses were encountered at 916.5 MHz, with efficiencies between 0.36% and 0.46% (net body loss ranging between 23.4 and 24.4 dB), Practical measurements were in good agreement with simulations, to within 2 dB at 418 MHz and 3 dB at 916.5 MHz. The degree of tissue-segmentation for whole-body models was found to have a minimal effect on calculated azimuthal radiation patterns and bodyworn radiation efficiency, provided the region surrounding the implanted source was sufficiently detailed.

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Monte Carlo simulation of chemical ordering kinetics in nano-layered L10 AB binary intermetallics was performed. The study addressed FePt thin layers considered as a material for ultra-high-density magnetic storage media and revealed metastability of the L10 c-variant superstructure with monoatomic planes parallel to the surface and off-plane easy magnetization. The layers, originally perfectly ordered in a c-variant of the L10 superstructure, showed homogeneous disordering running in parallel with a spontaneous re-orientation of the monoatomic planes leading to a mosaic microstructure composed of a- and b-L10-variant domains. The domains nucleated heterogeneously on the surface of the layer and grew discontinuously inwards its volume. Finally, the domains relaxed towards an equilibrium microstructure of the system. Two “atomistic-scale” processes: (i) homogeneous disordering and (ii) nucleation of the a- and b-L10-variant domains showed characteristic time scales. The same was observed for the domain microstructure relaxation. The discontinuous domain growth showed no definite driving force and proceeded due to thermal fluctuations. The above complex structural evolution has recently been observed experimentally in epitaxially deposited thin films of FePt.

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Using a multichannel Thomson spectrometer we have implemented a tomographic approach allowing the reconstruction of the emission characteristic of a laser driven proton source with high energy and spatial resolution. The results demonstrate the complexity of the temporal and spatial characteristics of such a source. The emitted proton beam, which is laminar and divergent at high energies, becomes convergent at low energies. This implies that a fraction of the proton beam having this kinetic energy is emitted in a collimated way from the target at the