9,326 research outputs found
Pressure Induced Charge Disproportionation in LaMnO
We present a total energy study as a function of volume in the cubic phase of
LaMnO. A charge disproportionated state into planes of
MnO/MnO was found. It is argued that the pressure
driven localisation/delocalisation transition might go smoothly through a
region of Mn and Mn coexistence.Comment: 3 pages, 1 figure, Conference Proceedings: Nanospintronics: Design
and Realization (Kyoto, Japan 24-28 May, 2004
Ensemble of Hankel Matrices for Face Emotion Recognition
In this paper, a face emotion is considered as the result of the composition
of multiple concurrent signals, each corresponding to the movements of a
specific facial muscle. These concurrent signals are represented by means of a
set of multi-scale appearance features that might be correlated with one or
more concurrent signals. The extraction of these appearance features from a
sequence of face images yields to a set of time series. This paper proposes to
use the dynamics regulating each appearance feature time series to recognize
among different face emotions. To this purpose, an ensemble of Hankel matrices
corresponding to the extracted time series is used for emotion classification
within a framework that combines nearest neighbor and a majority vote schema.
Experimental results on a public available dataset shows that the adopted
representation is promising and yields state-of-the-art accuracy in emotion
classification.Comment: Paper to appear in Proc. of ICIAP 2015. arXiv admin note: text
overlap with arXiv:1506.0500
Voltage-controlled current loops with nanofluidic diodes electrically coupled to solid state capacitors
[EN] We describe experimentally and theoretically voltage-controlled current loops obtained with nanofluidic diodes immersed in aqueous salt solutions. The coupling of these soft matter diodes with conventional electronic elements such as capacitors permits simple equivalent circuits which show electrical properties reminiscent of a resistor with memory. Different conductance levels can be reproducibly achieved under a wide range of experimental conditions (input voltage amplitudes and frequencies, load capacitances, electrolyte concentrations, and single pore and multipore membranes) by electrically coupling two types of passive components: the nanopores (ionics) and the capacitors (electronics). Remarkably, these electrical characteristics do not result from slow ionic redistributions within the nanopores, which should be difficult to control and would give only small conductance changes, but arise from the robust collective response of equivalent circuits. Coupling nanoscale diodes with conventional electronic elements allows interconverting ionic and electronic currents, which should be useful for electrochemical signal processing and energy conversion based on charge transport.Support from the Ministry of Economic Affairs and Competitiveness and FEDER (project MAT2015-65011-P), the Generalitat Valenciana (project Prometeo/GV/0069 for Groups of Excellence). M. A, S. N. and W. E acknowledge the funding from the Hessen State Ministry of Higher Education, Research and the Arts, Germany, in the frame of LOEWE project iNAPO. Z. S. acknowledges the funding from the National Science Foundation (CHE 1306058).Ramirez Hoyos, P.; Gómez Lozano, V.; Cervera, J.; Nasir, S.; Ali, M.; Ensinger, W.; Siwy, Z.... (2016). Voltage-controlled current loops with nanofluidic diodes electrically coupled to solid state
capacitors. RSC Advances. 6(60):54742-54746. https://doi.org/10.1039/c6ra08277gS5474254746660Fologea, D., Krueger, E., Mazur, Y. I., Stith, C., Okuyama, Y., Henry, R., & Salamo, G. J. (2011). Bi-stability, hysteresis, and memory of voltage-gated lysenin channels. Biochimica et Biophysica Acta (BBA) - Biomembranes, 1808(12), 2933-2939. doi:10.1016/j.bbamem.2011.09.005Pustovoit, M. A., Berezhkovskii, A. M., & Bezrukov, S. M. (2006). Analytical theory of hysteresis in ion channels: Two-state model. The Journal of Chemical Physics, 125(19), 194907. doi:10.1063/1.2364898Ramirez, P., Cervera, J., Ali, M., Ensinger, W., & Mafe, S. (2014). Logic Functions with Stimuli-Responsive Single Nanopores. ChemElectroChem, 1(4), 698-705. doi:10.1002/celc.201300255Martin, C. R., & Siwy, Z. S. (2007). CHEMISTRY: Learning Nature’s Way: Biosensing with Synthetic Nanopores. Science, 317(5836), 331-332. doi:10.1126/science.1146126Hou, X., & Jiang, L. (2009). Learning from Nature: Building Bio-Inspired Smart Nanochannels. ACS Nano, 3(11), 3339-3342. doi:10.1021/nn901402bZhang, H., Tian, Y., & Jiang, L. (2016). Fundamental studies and practical applications of bio-inspired smart solid-state nanopores and nanochannels. Nano Today, 11(1), 61-81. doi:10.1016/j.nantod.2015.11.001Chun, H., & Chung, T. D. (2015). Iontronics. Annual Review of Analytical Chemistry, 8(1), 441-462. doi:10.1146/annurev-anchem-071114-040202Tagliazucchi, M., & Szleifer, I. (2015). Transport mechanisms in nanopores and nanochannels: can we mimic nature? Materials Today, 18(3), 131-142. doi:10.1016/j.mattod.2014.10.020Misra, N., Martinez, J. A., Huang, S.-C. J., Wang, Y., Stroeve, P., Grigoropoulos, C. P., & Noy, A. (2009). Bioelectronic silicon nanowire devices using functional membrane proteins. Proceedings of the National Academy of Sciences, 106(33), 13780-13784. doi:10.1073/pnas.0904850106Senapati, S., Basuray, S., Slouka, Z., Cheng, L.-J., & Chang, H.-C. (2011). A Nanomembrane-Based Nucleic Acid Sensing Platform for Portable Diagnostics. Topics in Current Chemistry, 153-169. doi:10.1007/128_2011_142Haywood, D. G., Saha-Shah, A., Baker, L. A., & Jacobson, S. C. (2014). Fundamental Studies of Nanofluidics: Nanopores, Nanochannels, and Nanopipets. Analytical Chemistry, 87(1), 172-187. doi:10.1021/ac504180hPérez-Mitta, G., Tuninetti, J. S., Knoll, W., Trautmann, C., Toimil-Molares, M. E., & Azzaroni, O. (2015). Polydopamine Meets Solid-State Nanopores: A Bioinspired Integrative Surface Chemistry Approach To Tailor the Functional Properties of Nanofluidic Diodes. Journal of the American Chemical Society, 137(18), 6011-6017. doi:10.1021/jacs.5b01638Ali, M., Nasir, S., Ramirez, P., Ahmed, I., Nguyen, Q. H., Fruk, L., … Ensinger, W. (2011). Optical Gating of Photosensitive Synthetic Ion Channels. Advanced Functional Materials, 22(2), 390-396. doi:10.1002/adfm.201102146Ali, M., Nasir, S., Ramirez, P., Cervera, J., Mafe, S., & Ensinger, W. (2013). Carbohydrate-Mediated Biomolecular Recognition and Gating of Synthetic Ion Channels. The Journal of Physical Chemistry C, 117(35), 18234-18242. doi:10.1021/jp4054555Ali, M., Ahmed, I., Nasir, S., Ramirez, P., Niemeyer, C. M., Mafe, S., & Ensinger, W. (2015). Ionic Transport through Chemically Functionalized Hydrogen Peroxide-Sensitive Asymmetric Nanopores. ACS Applied Materials & Interfaces, 7(35), 19541-19545. doi:10.1021/acsami.5b06015Albrecht, T. (2011). How to Understand and Interpret Current Flow in Nanopore/Electrode Devices. ACS Nano, 5(8), 6714-6725. doi:10.1021/nn202253zLemay, S. G. (2009). Nanopore-Based Biosensors: The Interface between Ionics and Electronics. ACS Nano, 3(4), 775-779. doi:10.1021/nn900336jGomez, V., Ramirez, P., Cervera, J., Nasir, S., Ali, M., Ensinger, W., & Mafe, S. (2015). Charging a Capacitor from an External Fluctuating Potential using a Single Conical Nanopore. Scientific Reports, 5(1). doi:10.1038/srep09501Ramirez, P., Gomez, V., Cervera, J., Nasir, S., Ali, M., Ensinger, W., & Mafe, S. (2015). Energy conversion from external fluctuating signals based on asymmetric nanopores. Nano Energy, 16, 375-382. doi:10.1016/j.nanoen.2015.07.013Tybrandt, K., Forchheimer, R., & Berggren, M. (2012). Logic gates based on ion transistors. Nature Communications, 3(1). doi:10.1038/ncomms1869Apel, P. (2001). Track etching technique in membrane technology. Radiation Measurements, 34(1-6), 559-566. doi:10.1016/s1350-4487(01)00228-1Cervera, J., Schiedt, B., Neumann, R., Mafé, S., & Ramírez, P. (2006). Ionic conduction, rectification, and selectivity in single conical nanopores. The Journal of Chemical Physics, 124(10), 104706. doi:10.1063/1.2179797Ali, M., Ramirez, P., Mafé, S., Neumann, R., & Ensinger, W. (2009). A pH-Tunable Nanofluidic Diode with a Broad Range of Rectifying Properties. ACS Nano, 3(3), 603-608. doi:10.1021/nn900039fRamirez, P., Gomez, V., Verdia-Baguena, C., Nasir, S., Ali, M., Ensinger, W., & Mafe, S. (2016). Designing voltage multipliers with nanofluidic diodes immersed in aqueous salt solutions. Physical Chemistry Chemical Physics, 18(5), 3995-3999. doi:10.1039/c5cp07203dWang, D., Kvetny, M., Liu, J., Brown, W., Li, Y., & Wang, G. (2012). Transmembrane Potential across Single Conical Nanopores and Resulting Memristive and Memcapacitive Ion Transport. Journal of the American Chemical Society, 134(8), 3651-3654. doi:10.1021/ja211142eMomotenko, D., & Girault, H. H. (2011). Scan-Rate-Dependent Ion Current Rectification and Rectification Inversion in Charged Conical Nanopores. Journal of the American Chemical Society, 133(37), 14496-14499. doi:10.1021/ja2048368Zhang, A., & Lieber, C. M. (2015). Nano-Bioelectronics. Chemical Reviews, 116(1), 215-257. doi:10.1021/acs.chemrev.5b0060
Effective one-band electron-phonon Hamiltonian for nickel perovskites
Inspired by recent experiments on the Sr-doped nickelates,
, we propose a minimal microscopic model capable to describe
the variety of the observed quasi-static charge/lattice modulations and the
resulting magnetic and electronic-transport anomalies. Analyzing the motion of
low-spin (s=1/2) holes in a high-spin (S=1) background as well as their their
coupling to the in-plane oxygen phonon modes, we construct a sort of
generalized Holstein t-J Hamiltonian for the planes, which contains
besides the rather complex ``composite-hole'' hopping part non-local spin-spin
and hole-phonon interaction terms.Comment: 12 pages, LaTeX, submitted to Phys. Rev.
Geometrical quadrupolar frustration in DyB
Physical properties of DyB have been studied by magnetization, specific
heat, and ultrasonic measurements. The magnetic entropy change and the
ultrasonic properties in the intermediate phase II indicate that the degeneracy
of internal degrees of freedom is not fully lifted in spite of the formation of
magnetic order. The ultrasonic attenuation and the huge softening of
in phase II suggests existence of electric-quadrupolar (orbital) fluctuations
of the 4-electron. These unusual properties originate from the geometrical
quadrupolar frustration.Comment: 4 pages, 4 figures, accepted for publication in Journal of the
Physical Society of Japa
Effects of Prescribed Fire Timing on Stocker Cattle Performance, Native Plant Composition, Forage Biomass, and Root Carbohydrate Reserves in the Kansas Flint Hills: Year One of Six
Objective: Our objective was to document the effects of prescribed fire timing on yearling beef cattle performance, native plant composition, and forage biomass accumulation in the Kansas Flint Hills.
Study Description: Our study took place at the Kansas State Beef Stocker Unit located northwest of Manhattan, KS. Pastures were assigned to one of three prescribed burn treatments: early spring (April), mid-summer (August), or early fall (October). Treatments were applied and yearling heifers (n = 360) were subsequently grazed from May to August. Native plant composition and forage biomass were evaluated annually in late June and early July.
The Bottom Line: The first year of data from a six-year study indicated that prescribed fire timing affected stocker cattle performance and forage biomass availability but not basal cover of forage grasses and forbs
Competition between ferromagnetic and charge-orbital ordered phases in PrCaMnO for =1/4, 3/8, and 1/2
Spin, charge, and orbital structures in models for doped manganites are
studied by a combination of analytic mean-field and numerical relaxation
techniques. At realistic values for the electron-phonon and antiferromagnetic
spin couplings, a competition between a ferromagnetic (FM) phase and a
charge-orbital ordered (COO) insulating state is found for =1/4, 3/8, and
1/2, as experimentally observed in PrCaMnO for
=0.30.5. The theoretical predictions for the spin-charge-orbital
ordering pattern are compared with experiments. The FM-COO energy difference is
surprisingly small for the densities studied, result compatible with the
presence of a robust colossal-magnetoresistive effect in
PrCaMnO in a large density interval.Comment: 4 pages, Revtex, with 2 figures embedded in the text. Submitted to
Phys. Rev.
Universal Short-time Behaviour of the Dynamic Fully Frustrated XY Model
With Monte Carlo methods we investigate the dynamic relaxation of the fully
frustrated XY model in two dimensions below or at the Kosterlitz-Thouless phase
transition temperature. Special attention is drawn to the sublattice structure
of the dynamic evolution. Short-time scaling behaviour is found and
universality is confirmed. The critical exponent is measured for
different temperature and with different algorithms.Comment: 18 pages, LaTeX, 8 ps-figure
Soft spin waves in the low temperature thermodynamics of Pr_{0.7}Ca_{0.3}MnO_{3}
We present a detailed magnetothermal study of Pr(0.7)Ca(0.3)MnO(3), a
perovskite manganite in which an insulator-metal transition can be driven by
magnetic field, but also by pressure, visible light, x-rays, or high currents.
We find that the field-induced transition is associated with an enormous
release of energy which accounts for its strong irreversibility. In the
ferromagnetic metallic state, specific heat and magnetization measurements
indicate a much smaller spin wave stiffness than that seen in any other
manganite, which we attribute to spin waves among the ferromagnetically ordered
Pr moments. The coupling between the Pr and Mn spins may also provide a basis
for understanding the low temperature phase diagram of this most unusual
manganite.Comment: 10 pages, LATEX, 5 PDF figures, corrected typo
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