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Full-Text Articles in Physics

Interfacial Coherency And Ferroelectricity Of Batio3/Srtio3 Superlattice Films, Y. L. Li, S. Y. Hu, Dmitri Tenne, A. Soukiassian, D. G. Schlom, X. X. Xi, K. J. Choi Dec 2007

Interfacial Coherency And Ferroelectricity Of Batio3/Srtio3 Superlattice Films, Y. L. Li, S. Y. Hu, Dmitri Tenne, A. Soukiassian, D. G. Schlom, X. X. Xi, K. J. Choi

Physics Faculty Publications and Presentations

We studied the phase transitions, domain morphologies, and polarizations in BaTiO3/SrTiO3 superlattices grown on SrTiO3 substrates. Using the phase field approach, we discovered the remarkable influence of film/substrate interfacial coherency on the ferroelectricity of the SrTiO3 layers within a superlattice: it is an orthorhombic ferroelectric for an incoherent interface while it exhibits only induced polarization by the adjacent BaTiO3 layers for a coherent interface. We presented the domain morphologies within individual BaTiO3 and SrTiO3 layers which have different ferroelectric symmetries. The results are compared to ultraviolet Raman spectroscopy and variable temperature x-ray …


Non-Thiol Reagents Regulate Ryanodine Receptor Function By Redox Interactions That Modify Reactive Thiols, Benjamin S. Marinov, Rotimi O. Olojo, Ruohong Xia, Jonathan J. Abramson May 2007

Non-Thiol Reagents Regulate Ryanodine Receptor Function By Redox Interactions That Modify Reactive Thiols, Benjamin S. Marinov, Rotimi O. Olojo, Ruohong Xia, Jonathan J. Abramson

Physics Faculty Publications and Presentations

The Ca(2+) release channel (CRC) from sarcoplasmic reticulum (SR) is rich in thiol groups, and their oxidation/- reduction by thiol reagents activates/inhibits the CRC. Most channel regulators are not thiol reagents, and the mechanism of their action is illusive. Here the authors show that many channel activators act as electron acceptors, while many channel inhibitors act as electron donors in free radical reactions. The channel activator, caffeine, and the CRC inhibitor, tetracaine, are shown to interact competitively, which suggests that there exists a common site(s) on the CRC, that integrates the donor/acceptor effects of ligands. Moreover, channel activators shift the …


Computation Of Dark Frames In Digital Imagers, Ralf Widenhorn, Armin Rest, Morley M. Blouke, Richard L. Berry, Erik Bodegom Feb 2007

Computation Of Dark Frames In Digital Imagers, Ralf Widenhorn, Armin Rest, Morley M. Blouke, Richard L. Berry, Erik Bodegom

Physics Faculty Publications and Presentations

Dark current is caused by electrons that are thermally exited into the conduction band. These electrons are collected by the well of the CCD and add a false signal to the chip. We will present an algorithm that automatically corrects for dark current. It uses a calibration protocol to characterize the image sensor for different temperatures. For a given exposure time, the dark current of every pixel is characteristic of a specific temperature. The dark current of every pixel can therefore be used as an indicator of the temperature. Hot pixels have the highest signal-to-noise ratio and are the best …


The Challenge Of Understanding Radical Constructivism, Dewey I. Dykstra Jan 2007

The Challenge Of Understanding Radical Constructivism, Dewey I. Dykstra

Physics Faculty Publications and Presentations

Purpose: This contribution to the Festschrift honoring Ernst von Glasersfeld gives some insight into the perpetual problem of understanding radical constructivism (RC). Parallels with the Middle Way school of Buddhism appear to shed light on this challenge. Conclusions: The hegemony realism has over the thinking of even the most highly educated in our civilization plays a major role in their failure to understand RC. Those still subject to realism in their thinking interpret statements by those in RC in ways incompatible with RC. Until realists disequilibrate over mismatches between realist expectations and experiences, no alternative way of thinking is accessible …


“Once More Into The Breech…”, Dewey I. Dykstra Jan 2007

“Once More Into The Breech…”, Dewey I. Dykstra

Physics Faculty Publications and Presentations

No abstract provided.


Raman Study Of Oxygen Reduced And Re-Oxidized Strontium Titanate, Dmitri Tenne, I. E. Gonenli, A. Soukiassian, D. G. Schlom, S. M. Nakhmanson, K. M. Rabe, X. X. Xi Jan 2007

Raman Study Of Oxygen Reduced And Re-Oxidized Strontium Titanate, Dmitri Tenne, I. E. Gonenli, A. Soukiassian, D. G. Schlom, S. M. Nakhmanson, K. M. Rabe, X. X. Xi

Physics Faculty Publications and Presentations

We report Raman study of oxygen-reduced single crystal strontium titanate. Oxygen reduction leads to the appearance of the forbidden first order Raman peaks, as well as new spectral features attributed to the local vibrational modes associated with oxygen vacancies. This assignment is supported by ab initio calculations of phonon modes in SrTiO3 with introduced oxygen vacancies. Raman studies of re-oxidized samples show the same spectra as the initial single crystals. Comparison of Raman spectra of SrTiO3 thin films and reduced SrTiO3 single crystals demonstrates the importance of other factors such as polar grain boundaries in the lattice …


Fabrication Of Carbon Nanotube-Based Nanodevices Using A Combination Technique Of Focused Ion Beam And Plasma-Enhanced Chemical Vapor Deposition, Jianfeng Wu, Micah Eastman, Timothy Gutu, Madeline Wyse, Jun Jiao, S.-M. Kim, M. Mann, Y. Zhang, K. B. Teo Jan 2007

Fabrication Of Carbon Nanotube-Based Nanodevices Using A Combination Technique Of Focused Ion Beam And Plasma-Enhanced Chemical Vapor Deposition, Jianfeng Wu, Micah Eastman, Timothy Gutu, Madeline Wyse, Jun Jiao, S.-M. Kim, M. Mann, Y. Zhang, K. B. Teo

Physics Faculty Publications and Presentations

This study focuses on the fabrication of two nanodevice prototypes which utilized vertical and horizontal carbon nanotubes used the focused ion beam to localize the catalysts, followed by plasma-enhanced chemical vapor deposition. First, metal-gated carbon nanotube field emitter arrays were fabricated on multilayer substrates containing an imbedded catalyst layer. Second, horizontally aligned single-walled carbon nanotubes were grown on a transmission electron microscopy grid. This allows the carbon nanotubes to be directly analyzed in a transmission electron microscope. It is expected that the methodology introduced here will open up opportunities for the direct fabrication of carbon nanotube based nanodevices.


Three-Dimensional Structure Of Cdx (X= Se, Te) Nanocrystals By Total X-Ray Diffraction, S. K. Pradhan, Z. T. Deng, F. Tang, Y. Ren, Peter Moeck, V. Petkov Jan 2007

Three-Dimensional Structure Of Cdx (X= Se, Te) Nanocrystals By Total X-Ray Diffraction, S. K. Pradhan, Z. T. Deng, F. Tang, Y. Ren, Peter Moeck, V. Petkov

Physics Faculty Publications and Presentations

The three-dimensional structure of oleic acid-capped CdSe and thiol-capped CdTe nanocrystals used as quantum dots has been determined by total synchrotron radiationx-ray diffraction and atomic pair distribution function analysis. Both CdSe and CdTe are found to exhibit the zinc-blende-type atomic ordering. It is only slightly distorted in CdSe implying the presence of nanosize domains and very heavily distorted in CdTe due to the presence of distinct core-shell regions. The results well demonstrate the great potential of the experimental approach and thus encourage its wider application in quantum dot research.


Selective Growth Of Single-Crystalline Zno Nanowires On Doped Silicon, Rolf Könenkamp, Robert Campbell Word, M. Dosmailov, J. Meiss, Athavan Nadarajah Jan 2007

Selective Growth Of Single-Crystalline Zno Nanowires On Doped Silicon, Rolf Könenkamp, Robert Campbell Word, M. Dosmailov, J. Meiss, Athavan Nadarajah

Physics Faculty Publications and Presentations

We report the growth of single-crystalline ZnO nanowires on n- and p-type Si wafers by electrodeposition. On strongly doped n-type Si high-quality nanowires can be grown under similar conditions as used for metallic substrates. For low electron concentrations occurring in weakly n-type or in p-type wafers, nanowire growth is inhibited. This difference allows selective growth in strongly n-type areas. The inhibited growth on weakly n-type and p-type wafers can be improved by applying stronger cathodic electrode potentials or by illuminating the growth area. The wires on n-Si show efficient electroluminescence covering the visible and extending into the ultraviolet spectral range.


Quantum Physics And Welfare Policy?, Jack C. Straton Jan 2007

Quantum Physics And Welfare Policy?, Jack C. Straton

Physics Faculty Publications and Presentations

Welfare policy is examined through the paradoxical logic of Nagarjuna’s tetralema, providing a lens through which wave-particle duality in quantum mechanics is then viewed. Through this process students are challenged to radically expand their critical-thinking horizons beyond conventional dualistic bounds. They learn not only this key property of quantum reality, but have to come to grips with the nature of knowledge itself, and the degree to which they censor their own awarenesses.