250 research outputs found
Energy exchange between electron and molecular gases
Energy transfer between electron and molecular gase
Direct observation of Levy flight of holes in bulk n-InP
We study the photoluminescence spectra excited at an edge side of n-InP slabs
and observed from the broadside. In a moderately doped sample the intensity
drops off as a power-law function of the distance from the excitation - up to
several millimeters - with no change in the spectral shape.The hole
distribution is described by a stationary Levy-flight process over more than
two orders of magnitude in both the distance and hole concentration. For
heavily-doped samples, the power law is truncated by free-carrier absorption.
Our experiments are near-perfectly described by the Biberman-Holstein transport
equation with parameters found from independent optical experiments.Comment: 4 pages, 3 figure
Carotenoids and chlorophyll content in natural soap with addition of vegetative raw material
In the present study, we performed quantitative and qualitative determination of carotenoids and chlorophyll in five samples of natural soap with addition of vegetative raw material: Green tea, Chamerion angustifolium (L.) Holub, Trifolium pratense L., Alchemilla vulgaris L. and Urtica dioica L. There was developed the method of quantitative content of carotenoids and chlorophyll using spectrophotometry with analytical wavelength at 450 nm (carotenoids) and 667 nm (chlorophyll). Qualitative determination was carried out by the comparative TLC analysis. As mobile phases were used in the experiment following a mixed solvent of hexane-acetone (3: 1). Identification of carotenoids was carried out according to standard samples β -carotene and literature data
Atomic hydrogen and argon ground state density determination in a recombining plasma using visible light absorption spectroscopy
Charge state and time resolved plasma composition of a pulsed zirconium arc in a nitrogen environment
Learning from a fool: searching for the 'unmanaged' context for radical learning
Drawing on the existing theorizing of organizational learning from a radical perspective, this article attempts to problematize such notion of learning and position it within the existing organizational contexts informed by divergent types of rationality. The study scrutinizes these frameworks with a view to reflect on the potentiality for radical learning to occur within them. In this vein, the conceptual analysis of non-technical and non-marginal notions, namely, ‘spirituality’, ‘luck’ and ‘wisdom’, in different modes of rationality is conducted. This article demonstrates that since the conceptual inclusiveness is entailed by the specificity of sensemaking mechanisms, which these modes employ, the analysed notions can be approached as their litmus paper. The functionalist rationality types are found to be incommensurate with exigencies of the radical context for learning. In pursue of the conducive area for radical learning, the notions of unmanaged organization and the technology of foolishness provide the theoretical frame for the study, and their joint sensemaking context is discussed using examples. This unmanaged space driven by inclusive foolishness is recognized as one that enables the liminal sensemaking processes conducive for radical learning to occur
Regenerative oscillation and four-wave mixing in graphene optoelectronics
The unique linear and massless band structure of graphene, in a purely
two-dimensional Dirac fermionic structure, have led to intense research
spanning from condensed matter physics to nanoscale device applications
covering the electrical, thermal, mechanical and optical domains. Here we
report three consecutive first-observations in graphene-silicon hybrid
optoelectronic devices: (1) ultralow power resonant optical bistability; (2)
self-induced regenerative oscillations; and (3) coherent four-wave mixing, all
at a few femtojoule cavity recirculating energies. These observations, in
comparison with control measurements with solely monolithic silicon cavities,
are enabled only by the dramatically-large and chi(3) nonlinearities in
graphene and the large Q/V ratios in wavelength-localized photonic crystal
cavities. These results demonstrate the feasibility and versatility of hybrid
two-dimensional graphene-silicon nanophotonic devices for next-generation
chip-scale ultrafast optical communications, radio-frequency optoelectronics,
and all-optical signal processing.Comment: Accepted at Nature Photonics, July (2012
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