42,439 research outputs found
A VLSI compatible conducting polymer composite based "electronic nose" chip
The focus of this work would be to exploit the vapor detection technology developed recently at Caltech that forms the basis for a low power, simple "electronic nose". In this work we have integrated the sensors, signal preprocessing, signal processing, and data analysis functions into a single, low power, low cost, "nose chip". Such a device could be implantable covertly or overtly onto suspect sites, deployable through remote delivery methods, worn by soldiers for CW alerts and in principle for IFF or military/nonmilitary identification purposes, and for other areas of national security where low power, lightweight, small, chemical sensing is of importance
Tolkien’s Sub-Creation and Secondary Worlds: Implications for a Robust Moral Psychology
In his work, “On Fairy Stories,” J. R. R. Tolkien offers a detailed account of what he calls Sub-creation, along with the corresponding notions of Primary and Secondary Worlds. In this paper, I suggest that Tolkien’s concept of Sub-creation can be creatively appropriated in the realm of moral psychology and there applied to the fundamental relationship between self and other – or in Judeo-Christian terms, “I” and my neighbor. Through appeal to Tolkien’s thought and to the wider Christian theological tradition, and in constructive tension with the contemporary psychoanalytic attention to “intersubjectivity,” I attempt to elucidate the power and appropriate function of the human imagination to dispose us to good moral action, and so to bring us closer to ultimate happiness
Divine Foreknowledge and the Problem of Evil: Four Views
This paper examines the issues of divine foreknowledge and the Problem of Evil from the standpoint of four different theological systems: Open Theism, Arminianism, Molinism, and Calvinism. The author summarizes each view’s understanding of divine foreknowledge and then explains how this understanding applies to the view’s refutation of the Problem of Evil
The Sometimes “Craven Watchdog”: The Disparate Criminal-Civil Application of the Presumption Against Extraterritoriality
Increasingly, courts must decide whether U.S. law applies extraterritorially. Courts largely resolve questions of extraterritorial scope using tools of statutory construction. Of these tools, the presumption against extraterritoriality has been ascendant. However, this presumption is subject to two divergent lines of cases: Morrison v. National Australia Bank Ltd. affirmed the strict operation of the presumption in civil cases, but United States v. Bowman continues to govern the presumption\u27s looser role in criminal cases, thereby creating a doctrinal asymmetry. This Note furthers the argument that courts should reconcile Morrison and Bowman, by laying out three arguments for why an expansive Bowman exception is problematic and unsustainable. First, the two lines of cases create unjustified doctrinal incoherencies, given the interrelated contexts in which the presumption is applied and the rationales underlying the presumption. Second, an expansive exception to the presumption in criminal contexts undermines the smart allocation of authority between the branches of government. Finally, an expansive Bowman exception runs counter to the tradition of offering fair notice of criminal law\u27s prohibitions. This Note asserts that these arguments counsel for the abrogation or, at least, substantial narrowing of the Bowman exception, to harmonize it with Morrison\u27s stricter vision of the presumption against extraterritoriality
High-temperature durability considerations for HSCT combustor
The novel combustor designs for the High Speed Civil Transport will require high temperature materials with long term environmental stability. Higher liner temperatures than in conventional combustors and the need for reduced weight necessitates the use of advanced ceramic matrix composites. The combustor environment is defined at the current state of design, the major degradation routes are discussed for each candidate ceramic material, and where possible, the maximum use temperatures are defined for these candidate ceramics
Topological singularities and the general classification of Floquet-Bloch systems
Recent works have demonstrated that the Floquet-Bloch bands of
periodically-driven systems feature a richer topological structure than their
non-driven counterparts. The additional structure in the driven case arises
from the periodicity of quasienergy, the energy-like quantity that defines the
spectrum of a periodically-driven system. Here we develop a new paradigm for
the topological classification of Floquet-Bloch bands, based on the
time-dependent spectrum of the driven system's evolution operator throughout
one driving period. Specifically, we show that this spectrum may host
topologically-protected degeneracies at intermediate times, which control the
topology of the Floquet bands of the full driving cycle. This approach provides
a natural framework for incorporating the role of symmetries, enabling a
unified and complete classification of Floquet-Bloch bands and yielding new
insight into the topological features that distinguish driven and non-driven
systems.Comment: 19 pages, 6 figure
Transmission Infrared Spectra of CH_3-, CD_3-, and C_(10)H_(21)-Ge(111) Surfaces
The surface chemistry of CH_3–, CD_3–, and C_(10)H_(21)–Ge(111) surfaces prepared through a bromination/alkylation method have been investigated by infrared spectroscopy. Well-ordered CH_3–Ge(111) surfaces could be prepared only if, prior to bromination, the surface was etched with 6.0 M HCl or with a two-step etch of H_2O_2 (1.5 M)/HF (5.1 M) followed by a short HF (6.0 M) etch. The etching method used to make the Ge precursor surface, and the formation of a bromine-terminated intermediate Ge surface, were of critical importance to obtain clear, unambiguous infrared absorption peaks on the methyl-terminated Ge surfaces. Polarization-dependent absorption peaks observed at 1232 cm^(–1) for CH_3–Ge(111) surfaces and at 951 cm^(–1) for CD_3–Ge(111) surfaces were assigned to the methyl “umbrella” vibrational mode. A polarization-dependent peak at 2121 cm^(–1) for CD_3–Ge(111) surfaces was assigned to the symmetric methyl stretching mode. Polarization-independent absorption peaks at 755 cm^(–1) for CH_3–Ge(111) and at 577 cm^(–1) for CD_3–Ge(111) were assigned to the methyl rocking mode. These findings provide spectroscopic evidence that the methyl monolayer structure on the alkylated Ge is well-ordered and similar to that on analogous Si(111) surfaces, despite differences in the composition of the precursor surfaces. The X-ray photoelectron spectra of CH_3–Ge(111) surfaces, however, were not highly dependent upon the etching method and showed a constant C 1s:Ge 3d ratio, independent of the etching method. The infrared spectra of C_(10)H_(21)–Ge(111) surfaces were also not sensitive to the initial etching method. Hence, while the final packing density of the alkyl groups on the surface was similar for all etch methods studied, not all methods yielded a well-ordered Ge(111)/overlayer interface
Chemical, Electronic, and Electrical Properties of Alkylated Ge(111) Surfaces
The use of Ge in semiconductor electronics has been constrained by the lack of a simple method of passivating the crystal surface. Toward that end, we have explored the utility of chemically bonded hydrocarbon monolayers. Alkylated Ge(111) surfaces have been prepared by addition of 1-alkenes to the H-terminated Ge(111) surface as well as by a two-step halogenation/alkylation procedure. The chemical compositions of the resulting methyl-, ethyl-, and decyl-terminated surfaces have been evaluated using X-ray photoelectron spectroscopy (XPS). Thermal addition of 1-decene produced hydrophobic surfaces with 0.3 ± 0.1 monolayer of Ge oxide detected by XPS, whereas no oxide was observed on the methyl-, ethyl-, or decyl-terminated surfaces that were prepared using the two-step halogenation/alkylation method. Methyl-terminated Ge(111) surfaces prepared by the two-step method displayed a well-resolved C 1s XPS peak at a binding energy of 284 eV, consistent with carbon bonded to a less electronegative element such as Ge. The electronic properties of all of the alkylated surfaces were characterized by measurements of the surface recombination velocity as a function of an externally applied gate voltage. Treatment of HF-etched Ge(111) surfaces with Br2 vapor, followed by reaction with alkylmagnesium or alkyllithium reagents, yielded air-stable surfaces that had surface recombination velocities of 100 cm s^(−1) or less under flat-band conditions. The field-dependent surface recombination velocity experiments indicated that, in contact with air, methyl-terminated n-type Ge(111) samples had a negative surface potential approaching 300 mV, in contrast to the oxidized Ge(111) surface, which exhibited a strongly positive surface potential under the same conditions. Mercury contacts to n-type methyl-, ethyl-, or decyl-terminated Ge(111) substrates that were alkylated using the two-step method formed rectifying junctions with barrier heights of 0.6 ± 0.1 eV, whereas no measurable rectification was observed for Hg contacts to p-type Ge(111) substrates that were alkylated by the two-step method, to n-type Ge(111) substrates that were alkylated through addition of 1-decene, or to oxidized n-type Ge(111) samples
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