1,172 research outputs found

    Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change

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    A theory is described based on resonant thermal diffusion waves in the sun that appears to explain many details of the paleotemperature record for the last 5.3 million years. These include the observed periodicities, the relative strengths of each observed cycle, and the sudden emergence in time for the 100 thousand year cycle. Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism. The particular mechanism described here has been demonstrated empirically, although not previously invoked in the solar context. The theory also lacks most of the problems associated with Milankovitch cycles.Comment: in press with The Journal of Atmospheric and Solr Terrestrial Physic

    Quantum Cybernetics: A New Perspective for Nelson's Stochastic Theory, Nonlocality, and the Klein-Gordon Equation

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    The Klein-Gordon equation is shown to be equivalent to coupled partial differential equations for a sub-quantum Brownian movement of a ''particle'', which is both passively affected by, and actively affecting, a diffusion process of its generally nonlocal environment. This indicates circularly causal, or ''cybernetic'', relationships between ''particles'' and their surroundings. Moreover, in the relativistic domain, the original stochastic theory of Nelson is shown to hold as a limiting case only, i.e., for a vanishing quantum potential.Comment: 21 pages; published in Phys. Lett. A 296 (2002) 1 -

    Electron and Phonon Thermal Waves in Semiconductors: an Application to Photothermal Effects

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    The electron and phonon temperature distribution function are calculated in semiconductors. We solved the coupled one-dimensional heat-diffussion equations in the linear approximation in which the physical parameters on the sample are independent of the temperature. We also consider the heat flux at the surface of the semiconductor as a boundary condition for each electron and phonon systems instead of using a fixed temperature. From this, we obtain an expression for electron and phonon temperature respectively. The characterization of the thermal waves properties is duscussed and some practical procedures for this purpose provide us information about the electron and phonon thermal parameters.Comment: 12 pages, amstex and amssymb macro package (LaTeX2e edition

    Thermal Diffusion of a Two Layer System

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    In this paper thermal conductivity and thermal diffusivity of a two layer system is examined from the theoretical point of view. We use the one dimensional heat diffusion equation with the appropriate solution in each layer and boundary conditions at the interfaces to calculate the heat transport in this bounded system. We also consider the heat flux at the surface of the samle as boundary condition instead of using a fixed tempertaure. From this, we obtain an expression for the efective thermal diffusivity of the composite sample in terms of the thermal diffusivity of its constituent materials whithout any approximations.Comment: 16 pages, 1 figure, RevTeX v. 3.0 macro packag

    Impulse Photothermal Evaluation of Materials Via Frequency Modulated Optical Reflectance II: Experimental

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    Recently, a powerful method of photothermal detection was reported which enabled thermal wave imaging to be carried out on micron sized structures in semiconductors [1,2]. The new method utilized the photothermally induced modulation of the sample’s surface optical reflectivity to detect thermal wave phenomena at bandwidths exceeding 10 MHz. The wide bandwidth capabilities of the method enabled very shallow structures to be analyzed in semiconducting materials because of the relationship that exists between the modulation frequency of the excitation beam and the thermal diffusion length

    Noncontacting Photothermal Radiometry of MOS Capacitor Structures: The Frequency-Domain and DLTS Approaches

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    The measurements of photoexcited excess carrier lifetime and activation energies in a semiconductor are useful in the characterization of the quality of semiconductor materials and in evaluating the performance of working semiconductor devices. The noncontact method of photothermal infrared radiometry (PTR), with both frequency-domain (PTR-FD) [1–3] and rate-window (PTR-RW) [4,5] detection configurations has been shown to be promising for remote on-line or off-line impurity/electronic defect diagnostics. A new PTR deep-level transient spectroscopy (PTR-DLTS) which combines the PTR-RW with semiconductor temperature ramping has been developed recently [6] and found to possess high spectral peak separation and spatial resolution

    Fundamentals of carrier diffusion waves in electronic solids

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    Photocarriers in semiconductors excited by modulated laser sources give rise to charge diffusion waves that can be used to study and characterize the electronic transport properties of materials and devices. In this talk the concept of carrier diffusion waves (CDW) will be introduced for continuous-band semiconductors (e.g. Si); and of hopping diffusion waves in nanolayers (e.g. colloidal quantum dot (CQD) excitonic ensembles)

    Fundamentals of carrier diffusion waves in electronic solids

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