ASU Scholarship Showcase

Permanent Link Feedback

Date Range
2006 2017

Mechanical oscillations or vibrations on spacecraft, also called pointing jitter, cause geometric distortions and/or smear in high resolution digital images acquired from orbit. Geometric distortion is especially a problem with pushbroom type sensors, such as the High Resolution Imaging Science Experiment (HiRISE) instrument on board the Mars Reconnaissance Orbiter (MRO). Geometric distortions occur at a range of frequencies that may not be obvious in the image products, but can cause problems with stereo image correlation in the production of digital elevation models, and in measuring surface changes over time in orthorectified images. The HiRISE focal plane comprises a staggered array ...

Contributors
Sutton, S. S., Boyd, Aaron, Kirk, R. L., et al.
Created Date
2017-08-16

The giant magnetoresistance (GMR) of a point contact between a Co/Cu multilayer and a superconductor tip varies for different bias voltage. Direct measurement of spin polarization by Andreev reflection spectroscopy reveals that the GMR change is due to a change in spin polarization. This work demonstrates that the GMR structure can be utilized as a spin source and that the spin polarization can be continuously controlled by using an external magnetic field.

Contributors
Gifford, Jessica, Zhao, Gejian, Li, Bochao, et al.
Created Date
2016-05-23

Increasing penetration of energy efficiency programs and distributed renewable energy generation has imposed significant challenges for utilities to recoup their large upfront costs. There is a heated debate on what surcharges should be implemented to help the utilities recover their fixed costs; however, very few studies focus on consumers’ attitudes regarding this topic. This study surveys about 190 residential consumers throughout the United States in November 2015, investigating their preferences and attitudes towards extra demand charges and volumetric energy price increases. We apply probit models and regress consumers’ attitudes on selected socio-demographic and behavioral variables. The results indicate the homeowners ...

Contributors
Liang, Jing, Qiu, Yueming, Padmanabhan, Poornima, et al.
Created Date
2017-08-19

A model of low-temperature polar liquids is constructed that accounts for the configurational heat capacity, entropy, and the effect of a strong electric field on the glass transition. The model is based on the Padé-truncated perturbation expansions of the liquid state theory. Depending on parameters, it accommodates an ideal glass transition of vanishing configurational entropy and its avoidance, with a square-root divergent enumeration function at the point of its termination. A composite density-temperature parameter ρ[superscript γ]/T, often used to represent combined pressure and temperature data, follows from the model. The theory is in good agreement with the experimental data for ...

Contributors
Matyushov, Dmitry, College of Liberal Arts and Sciences, Department of Physics, et al.
Created Date
2016-07-20

Protein evolution is most commonly studied by analyzing related protein sequences and generating ancestral sequences through Bayesian and Maximum Likelihood methods, and/or by resurrecting ancestral proteins in the lab and performing ligand binding studies to determine function. Structural and dynamic evolution have largely been left out of molecular evolution studies. Here we incorporate both structure and dynamics to elucidate the molecular principles behind the divergence in the evolutionary path of the steroid receptor proteins. We determine the likely structure of three evolutionarily diverged ancestral steroid receptor proteins using the Zipping and Assembly Method with FRODA (ZAMF). Our predictions are within ...

Contributors
Glembo, Tyler, Farrell, Daniel W., Gerek, Z. Nevin, et al.
Created Date
2012-03-29

Background Grip strength, walking speed, chair rising and standing balance time are objective measures of physical capability that characterise current health and predict survival in older populations. Socioeconomic position (SEP) in childhood may influence the peak level of physical capability achieved in early adulthood, thereby affecting levels in later adulthood. We have undertaken a systematic review with meta-analyses to test the hypothesis that adverse childhood SEP is associated with lower levels of objectively measured physical capability in adulthood. Methods and Findings Relevant studies published by May 2010 were identified through literature searches using EMBASE and MEDLINE. Unpublished results were obtained ...

Contributors
Birnie, Kate, Cooper, Rachel, Martin, Richard M., et al.
Created Date
2011-01-26

Salmonella enterica serovar Typhimurium genome encodes 13 fimbrial operons. Most of the fimbriae encoded by these operons are not produced under laboratory conditions but are likely to be synthesized in vivo. We used an in vivo expression technology (IVET) strategy to identify four fimbrial operons, agf, saf, sti, and stc that are expressed in the spleen. When any three of these operons were deleted, the strain retained wild-type virulence. However, when all four operons were deleted, the resulting strain was completely attenuated, indicating that these four fimbriae play functionally redundant roles critical for virulence. In mice, oral doses of as ...

Contributors
Laniewski, Pawel, Baek, Chang-Ho, Roland, Kenneth, et al.
Created Date
2017-08-22

We study the low efficiency droop characteristics of semipolar InGaN light-emitting diodes (LEDs) using modified rate equation incoporating the phase-space filling (PSF) effect where the results on c-plane LEDs are also obtained and compared. Internal quantum efficiency (IQE) of LEDs was simulated using a modified ABC model with different PSF filling (n[subscript 0]), Shockley-Read-Hall (A), radiative (B), Auger (C) coefficients and different active layer thickness (d), where the PSF effect showed a strong impact on the simulated LED efficiency results. A weaker PSF effect was found for low-droop semipolar LEDs possibly due to small quantum confined Stark effect, short carrier ...

Contributors
Fu, Houqiang, Lu, Zhijian, Zhao, Yuji, et al.
Created Date
2016-06-15

InGaN semiconductors are promising candidates for high-efficiency next-generation thin film solar cells. In this work, we study the photovoltaic performance of single-junction and two-junction InGaN solar cells using a semi-analytical model. We analyze the major loss mechanisms in InGaN solar cell including transmission loss, thermalization loss, spatial relaxation loss, and recombination loss. We find that transmission loss plays a major role for InGaN solar cells due to the large bandgaps of III-nitride materials. Among the recombination losses, Shockley-Read-Hall recombination loss is the dominant process. Compared to other III-V photovoltaic materials, we discovered that the emittance of InGaN solar cells is ...

Contributors
Huang, Xuangqi, Fu, Houqiang, Chen, Hong, et al.
Created Date
2016-06-01

The quantum anomalous Hall effect (QAHE) that emerges under broken time-reversal symmetry in topological insulators (TIs) exhibits many fascinating physical properties for potential applications in nanoelectronics and spintronics. However, in transition metal–doped TIs, the only experimentally demonstrated QAHE system to date, the QAHE is lost at practically relevant temperatures. This constraint is imposed by the relatively low Curie temperature (T[subscript c]) and inherent spin disorder associated with the random magnetic dopants. We demonstrate drastically enhanced T[subscript c] by exchange coupling TIs to Tm[subscript 3]Fe[subscript 5]O[subscript 12], a high-T[subscript c] magnetic insulator with perpendicular magnetic anisotropy. Signatures showing that the TI ...

Contributors
Tang, Chi, Chang, Cui-Zu, Zhao, Gejian, et al.
Created Date
2017-06-23