2,840 research outputs found
Low-voltage nanodomain writing in He-implanted lithium niobate crystals
A scanning force microscope tip is used to write ferroelectric domains in
He-implanted single-crystal lithium niobate and subsequently probe them by
piezoresponse force microscopy. Investigation of cross-sections of the samples
showed that the buried implanted layer, \,\textmu m below the surface,
is non-ferroelectric and can thus act as a barrier to domain growth. This
barrier enabled stable surface domains of \,\textmu m size to be written
in 500\,\textmu m-thick crystal substrates with voltage pulses of only 10\,V
applied to the tip
Exploring a rheonomic system
A simple and illustrative rheonomic system is explored in the Lagrangian
formalism. The difference between Jacobi's integral and energy is highlighted.
A sharp contrast with remarks found in the literature is pointed out. The
non-conservative system possess a Lagrangian not explicitly dependent on time
and consequently there is a Jacobi's integral. The Lagrange undetermined
multiplier method is used as a complement to obtain a few interesting
conclusion
Achieving sub-diffraction imaging through bound surface states in negative-refracting photonic crystals at the near-infrared
We report the observation of imaging beyond the diffraction limit due to
bound surface states in negative refraction photonic crystals. We achieve an
effective negative index figure-of-merit [-Re(n)/Im(n)] of at least 380, ~125x
improvement over recent efforts in the near-infrared, with a 0.4 THz bandwidth.
Supported by numerical and theoretical analyses, the observed near-field
resolution is 0.47 lambda, clearly smaller than the diffraction limit of 0.61
lambda. Importantly, we show this sub-diffraction imaging is due to the
resonant excitation of surface slab modes, allowing refocusing of
non-propagating evanescent waves
Asymptotics of relative heat traces and determinants on open surfaces of finite area
The goal of this paper is to prove that on surfaces with asymptotically cusp
ends the relative determinant of pairs of Laplace operators is well defined. We
consider a surface with cusps (M,g) and a metric h on the surface that is a
conformal transformation of the initial metric g. We prove the existence of the
relative determinant of the pair under suitable
conditions on the conformal factor. The core of the paper is the proof of the
existence of an asymptotic expansion of the relative heat trace for small
times. We find the decay of the conformal factor at infinity for which this
asymptotic expansion exists and the relative determinant is defined. Following
the paper by B. Osgood, R. Phillips and P. Sarnak about extremal of
determinants on compact surfaces, we prove Polyakov's formula for the relative
determinant and discuss the extremal problem inside a conformal class. We
discuss necessary conditions for the existence of a maximizer.Comment: This is the final version of the article before it gets published. 51
page
Measuring attitude toward theistic faith : assessing the Astley-Francis Scale among Christian, Muslim and secular youth in England
Empirical research within the social scientific study of religion in general and within the psychology of religion in particular remains very conscious of the complex nature of its subject matter. Empirical research in this field needs to take cognisance of the many forms in which religion is expressed (say, Buddhism, Christianity, Hinduism, Islam, Judaism, and Sikhism) and the many facets within the forms (say, beliefs, behaviours and affiliation). Working in the 1970s, Francis (1978a; 1978b) advanced the view that the attitudinal dimension of religion offered a particularly fruitful basis for coordinating empirical enquiry into the correlates, antecedents and consequences of religiosity across the life span
Symbolic Software for the Painleve Test of Nonlinear Ordinary and Partial Differential Equations
The automation of the traditional Painleve test in Mathematica is discussed.
The package PainleveTest.m allows for the testing of polynomial systems of
ordinary and partial differential equations which may be parameterized by
arbitrary functions (or constants). Except where limited by memory, there is no
restriction on the number of independent or dependent variables. The package is
quite robust in determining all the possible dominant behaviors of the Laurent
series solutions of the differential equation. The omission of valid dominant
behaviors is a common problem in many implementations of the Painleve test, and
these omissions often lead to erroneous results. Finally, our package is
compared with the other available implementations of the Painleve test.Comment: Published in the Journal of Nonlinear Mathematical Physics
(http://www.sm.luth.se/math/JNMP/), vol. 13(1), pp. 90-110 (Feb. 2006). The
software can be downloaded at either http://www.douglasbaldwin.com or
http://www.mines.edu/fs_home/wherema
Metaphoric coherence: Distinguishing verbal metaphor from `anomaly\u27
Theories and computational models of metaphor comprehension generally circumvent the question of metaphor versus “anomaly” in favor of a treatment of metaphor versus literal language. Making the distinction between metaphoric and “anomalous” expressions is subject to wide variation in judgment, yet humans agree that some potentially metaphoric expressions are much more comprehensible than others. In the context of a program which interprets simple isolated sentences that are potential instances of cross‐modal and other verbal metaphor, I consider some possible coherence criteria which must be satisfied for an expression to be “conceivable” metaphorically. Metaphoric constraints on object nominals are represented as abstracted or extended along with the invariant structural components of the verb meaning in a metaphor. This approach distinguishes what is preserved in metaphoric extension from that which is “violated”, thus referring to both “similarity” and “dissimilarity” views of metaphor. The role and potential limits of represented abstracted properties and constraints is discussed as they relate to the recognition of incoherent semantic combinations and the rejection or adjustment of metaphoric interpretations
Effect of Coulomb interactions on the physical observables of graphene
We give an update of the situation concerning the effect of electron-electron
interactions on the physics of a neutral graphene system at low energies. We
revise old renormalization group results and the use of 1/N expansion to
address questions of the possible opening of a low-energy gap, and the
magnitude of the graphene fine structure constant. We emphasize the role of
Fermi velocity as the only free parameter determining the transport and
electronic properties of the graphene system and revise its renormalization by
Coulomb interactions in the light of recent experimental evidence.Comment: Proceedings of the Nobel Symposium on graphene 2010, to appear as a
special issue in Physica Script
Beyond Laggards and Morons: The Complicated World of Special Education
Robert L. Osgood responds to Benjamin Kelsey Kearl\u27s biographical approach to special education in Of Laggards and Morons
Expanding the Scarcity Rationale: The Constitutionality of Public Access Requirements in Cable Franchise Agreements
This Note argues that public access requirements should be upheld because they are constitutional and because they further the goals of the first amendment. As background for the debate over public access, Part I provides a brief description of cable television\u27s history and regulation and discusses the case law concerning public access requirements. Part II examines the nature of the first amendment interests at stake in public access requirements. Before resolving the question of which interests should be protected, Part III argues that an expanded scarcity rationale should be used to justify cable regulation under the first amendment. Part IV asserts that public access requirements are constitutional under the expanded scarcity rationale and that they further the goals of the rationale. Finally, this Part emphasizes the effectiveness of public access channels in promoting the goals of the first amendment and the limited nature of the intrusion on editorial discretion posed by public access requirements. This Note concludes that public access requirements are not only constitutional, but that they offer a sensible compromise of the first amendment interests of both cable operators and the public
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