1,172 research outputs found
Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change
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
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
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
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
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
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
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)
Diffusion-wave inverse problem thermal conductivity depth-profile reconstructions using an integral equation approach
Diffusion-wave inverse problem thermal conductivity depth-profile reconstructions using an integral equation approach
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