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University of Nebraska - Lincoln

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2015

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Articles 571 - 585 of 585

Full-Text Articles in Physical Sciences and Mathematics

Surface Analytical Investigation On Organometal Triiodide Perovskite, Chengong Wang, Xiaoliang Liu, Congcong Wang, Zhengguo Xiao, Cheng Bi, Yuchuan Shao, Jinsong Huang, Yongli Gao Jan 2015

Surface Analytical Investigation On Organometal Triiodide Perovskite, Chengong Wang, Xiaoliang Liu, Congcong Wang, Zhengguo Xiao, Cheng Bi, Yuchuan Shao, Jinsong Huang, Yongli Gao

Department of Mechanical and Materials Engineering: Faculty Publications

In a little over a year, there has been an unexpected breakthrough and rapid evolution of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite materials. This technology has the potential to produce solar cells with the very highest efficiencies while retaining the very lowest cost. The authors have measured the electronic density of states of CH3NH3PbI3 using ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and x-ray photoemission spectroscopy (XPS). The valence band maximum and conduction band minimum positions are obtained from the UPS and IPES spectra, respectively, by linear extrapolation of …

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Phase Transformation And Magnetic Properties Of Rapidly Solidified Mn-Al-C Alloys Modified With Zr, Yunlong Geng, Micheal J. Lucis, Pamela Rasmussen, Jeffrey E. Shield Jan 2015

Phase Transformation And Magnetic Properties Of Rapidly Solidified Mn-Al-C Alloys Modified With Zr, Yunlong Geng, Micheal J. Lucis, Pamela Rasmussen, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Faculty Publications

Mn54-xAl43C3Zrx (x=1, 3) alloys were prepared by rapid solidification followed by heat treatment to produce the ferromagnetic s phase. The substitution of Zr for Mn in the structure resulted in an increase of the saturation magnetization (Ms) compared to that of Mn54-xAl43C3. While the highest Ms (12861 emu/g) was obtained in Mn54-xAl43C3Zr1, the coercivity was also improved to 1.62 kOe, compared to 1.25 kOe for Mn54-xAl43C3. To further improve the coercivity through grain …

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Few-Layer Titanium Trisulfide (Tis3) Field-Effect Transistors, Alexey Lipatov, Peter M. Wilson, Mikhail Shekhirev, Jacob D. Teeter, Ross Netusil, Alexander Sinitskii Jan 2015

Few-Layer Titanium Trisulfide (Tis3) Field-Effect Transistors, Alexey Lipatov, Peter M. Wilson, Mikhail Shekhirev, Jacob D. Teeter, Ross Netusil, Alexander Sinitskii

Chemistry Department: Faculty Publications

Titanium trisulfide (TiS3) is a promising layered semiconductor material. Several-mm-long TiS3 whiskers can be conveniently grown by the direct reaction of titanium and sulfur. In this study, we exfoliated these whiskers using the adhesive tape approach and fabricated few-layer TiS3 field-effect transistors (FETs). The TiS3 FETs showed an n-type electronic transport with roomtemperature field-effect mobilities of 18-24 cm2V-1s-1 and ON/OFF ratios up to 300. We demonstrate that TiS3 is compatible with the conventional atomic layer deposition (ALD) procedure for Al2O3. ALD of alumina on TiS3 …

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Fast Strain Wave Induced Magnetization Changes In Long Cobalt Bars: Domain Motion Versus Coherent Rotation, S Davis, J A. Borchers, B B. Maranville, Shireen Adenwalla Jan 2015

Fast Strain Wave Induced Magnetization Changes In Long Cobalt Bars: Domain Motion Versus Coherent Rotation, S Davis, J A. Borchers, B B. Maranville, Shireen Adenwalla

Department of Physics and Astronomy: Faculty Publications

A high frequency (88 MHz) traveling strain wave on a piezoelectric substrate is shown to change the magnetization direction in 40 lm wide Co bars with an aspect ratio of 103. The rapidly alternating strain wave rotates the magnetization away from the long axis into the short axis direction, via magnetoelastic coupling. Strain-induced magnetization changes have previously been demonstrated in ferroelectric/ferromagnetic heterostructures, with excellent fidelity between the ferromagnet and the ferroelectric domains, but these experiments were limited to essentially dc frequencies. Both magneto-optical Kerr effect and polarized neutron reflectivity confirm that the traveling strain wave does rotate the magnetization away …

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Continuous Third Harmonic Generation In A Terahertz Driven Modulated Nanowire, Kathleen E. Hamilton, Alexey Kovalev, Amrit De, Leonid P. Pryadko Jan 2015

Continuous Third Harmonic Generation In A Terahertz Driven Modulated Nanowire, Kathleen E. Hamilton, Alexey Kovalev, Amrit De, Leonid P. Pryadko

Department of Physics and Astronomy: Faculty Publications

We consider the possibility of observing continuous third-harmonic generation using a strongly driven, single-band one-dimensional metal. In the absence of scattering, the quantum efficiency of frequency tripling for such a system can be as high as 93%. Combining the Floquet quasienergy spectrum with the Keldysh Green’s function technique, we derive a semiclassical master equation for a one-dimensional band of strongly and rapidly driven electrons in the presence of weak scattering by phonons. The power absorbed from the driving field is continuously dissipated by phonon modes, leading to a quasi-equilibrium in the electron distribution. We use the Kronig-Penney model with varying …

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Thresholds For Correcting Errors, Erasures, And Faulty Syndrome Measurements In Degenerate Quantum Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko Jan 2015

Thresholds For Correcting Errors, Erasures, And Faulty Syndrome Measurements In Degenerate Quantum Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko

Department of Physics and Astronomy: Faculty Publications

We suggest a technique for constructing lower (existence) bounds for the fault-tolerant threshold to scalable quantum computation applicable to degenerate quantum codes with sublinear distance scaling. We give explicit analytic expressions combining probabilities of erasures, depolarizing errors, and phenomenological syndrome measurement errors for quantum low-density parity-check codes with logarithmic or larger distances. These threshold estimates are parametrically better than the existing analytical bound based on percolation.

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Spin Glass Reflection Of The Decoding Transition For Quantum Error Correcting Codes, Alexey Kovalev, Leonid P. Pryadko Jan 2015

Spin Glass Reflection Of The Decoding Transition For Quantum Error Correcting Codes, Alexey Kovalev, Leonid P. Pryadko

Department of Physics and Astronomy: Faculty Publications

We study the decoding transition for quantum error correcting codes with the help of a mapping to random-bond Wegner spin models. Families of quantum low density parity-check (LDPC) codes with a finite decoding threshold lead to both known models (e.g., random bond Ising and random plaquette Z2 gauge models) as well as unexplored earlier generally non-local disordered spin models with non-trivial phase diagrams. The decoding transition corresponds to a transition from the ordered phase by proliferation of "post-topological" extended defects which generalize the notion of domain walls to non-local spin models. In recently discovered quantum LDPC code families with …

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Metadata And Linked Data In Word Sense Disambiguation, Matthew Corsmeier Jan 2015

Metadata And Linked Data In Word Sense Disambiguation, Matthew Corsmeier

Library Philosophy and Practice (e-journal)

Word Sense Disambiguation (WSD) can be assisted by taking advantage of the metadata embedded in the various ontologies, lexica, databases, etc… that exist in the Semantic Web. Automated processes that exploit the links already present in the Semantic Web can strengthen parsing of word senses by using user-contributed and semantically-linked data. These processes are only possible because of a commitment to interoperability and the creation of shared standards. This paper will review some of the most heavily used Linguistic Linked Open Data (LLOD) tools and models which show the most promise for using metadata to alleviate problems caused by polysemous …

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Investigating Diurnal And Seasonal Climatic Response To Land Use And Land Cover Change Over Monsoon Asia With The Community Earth System Model, Rezaul Mahmood Jan 2015

Investigating Diurnal And Seasonal Climatic Response To Land Use And Land Cover Change Over Monsoon Asia With The Community Earth System Model, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

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Neural Network Analysis On The Effect Of Heat Fluxes On Greenhouse Gas Emissions From Anaerobic Swine Waste Treatment Lagoon, N. Lovanh, J. Loughrin, M. Rysz, A. I. Quintanar, B. T. Oh, Rezaul Mahmood Jan 2015

Neural Network Analysis On The Effect Of Heat Fluxes On Greenhouse Gas Emissions From Anaerobic Swine Waste Treatment Lagoon, N. Lovanh, J. Loughrin, M. Rysz, A. I. Quintanar, B. T. Oh, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

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Nebraska Statewide Groundwater-Level Monitoring Report 2015, A. R. Young, M. E. Burbach, L. M. Howard Jan 2015

Nebraska Statewide Groundwater-Level Monitoring Report 2015, A. R. Young, M. E. Burbach, L. M. Howard

Conservation and Survey Division

No abstract provided.

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Evaluating A Satellite-Based Seasonal Evapotranspiration Product And Identifying Its Relationship With Other Satellite-Derived Products And Crop Yield: A Case Study For Ethiopia, Tsegaye Tadesse, Gabriel B. Senay, Getachew Berhan, Teshome Regassa, Shimelis Beyene Jan 2015

Evaluating A Satellite-Based Seasonal Evapotranspiration Product And Identifying Its Relationship With Other Satellite-Derived Products And Crop Yield: A Case Study For Ethiopia, Tsegaye Tadesse, Gabriel B. Senay, Getachew Berhan, Teshome Regassa, Shimelis Beyene

Department of Agronomy and Horticulture: Faculty Publications

Satellite-derived evapotranspiration anomalies and normalized difference vegetation index (NDVI) products from Moderate Resolution Imaging Spectroradiometer (MODIS) data are currently used for African agricultural drought monitoring and food security status assessment. In this study, a process to evaluate satellite-derived evapotranspiration (ETa) products with a geospatial statistical exploratory technique that uses NDVI, satellite-derived rainfall estimate (RFE), and crop yield data has been developed. The main goal of this study was to evaluate the ETa using the NDVI and RFE, and identify a relationship between the ETa and Ethiopia’s cereal crop (i.e., teff, sorghum, corn/maize, barley, and wheat) yields during the main rainy …

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Energetics, Structure, And Rovibrational Spectroscopic Properties Of The Sulfurous Anions Sno− And Osn−, Ryan C. Fortenberry, Joseph S. Francisco Jan 2015

Energetics, Structure, And Rovibrational Spectroscopic Properties Of The Sulfurous Anions Sno− And Osn−, Ryan C. Fortenberry, Joseph S. Francisco

Chemistry Department: Faculty Publications

The SNO− and OSN− anions are shown in this work to be very stable negatively charged species in line with other recent work [T. Trabelsi et al., J. Chem. Phys. 143, 164301 (2015)]. Utilizing established quartic force field techniques, the structural and rovibrational data for these anions are produced. The SNO− anion is less linear and has weaker bonds than the corresponding neutral radical giving much smaller rotational constants.OSN− is largely unchanged in these regards with inclusion of the additional electron.The S–N bond is actually stronger,and the rotational constants of OSN− versus OSN are …

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Simulation Evidence Of Hexagonal-To-Tetragonal Znse Structure Transition: A Monolayer Material With A Wide-Range Tunable Direct Bandgap, Lei Li, Pengfei Li, Ning Lu, Jun Dai, Xiao Cheng Zeng Jan 2015

Simulation Evidence Of Hexagonal-To-Tetragonal Znse Structure Transition: A Monolayer Material With A Wide-Range Tunable Direct Bandgap, Lei Li, Pengfei Li, Ning Lu, Jun Dai, Xiao Cheng Zeng

Chemistry Department: Faculty Publications

2D material with tunable direct bandgap in the intermediate region (i.e., ≈2–3 eV) is key to the achievement of high efficiency in visible-light optical devices. Herein, a simulation evidence of structure transition of monolayer ZnSe from the experimental pseudohexagonal structure to the tetragonal structure (t-ZnSe) under lateral pressure is shown, suggesting a possible fabrication route to achieve the t-ZnSe monolayer. The as-produced t-ZnSe monolayer exhibits highly tunable bandgap under the biaxial strains, allowing strain engineering of t-ZnSe’s bandgap over a wide range of 2–3 eV. Importantly, even under the biaxial strain up to 7%, the t-ZnSe monolayer still keeps its …

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Uncertainty Analysis Of An Irrigation Scheduling Model For Water Management In Crop Production, S. Mun, G. F. Sassenrath, Amy M. Schmidt, N. Lee, M. C. Wadsworth, B. Rice, Jason Q, Corbitt, J. M. Schneider, M. L. Tagert, J. Pote, R. Prabhu Jan 2015

Uncertainty Analysis Of An Irrigation Scheduling Model For Water Management In Crop Production, S. Mun, G. F. Sassenrath, Amy M. Schmidt, N. Lee, M. C. Wadsworth, B. Rice, Jason Q, Corbitt, J. M. Schneider, M. L. Tagert, J. Pote, R. Prabhu

Department of Biological Systems Engineering: Papers and Publications

Irrigation scheduling tools are critical to allow producers to effectively manage water resources for crop production. To be useful, these tools need to be accurate, complete, and relatively reliable. The current work presents an uncertainty analysis and its results for the Mississippi Irrigation Scheduling Tool (MIST) model, showing the margin of error (uncertainty) of the resulting irrigation advice arising solely from the propagation of measurement uncertainty through the MIST calculations. The final relative uncertainty in the water balance value from MIST was shown to be around 9% of that value, which is in the normal range of the margin of …

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