University of Houston

About: University of Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23074 authors who have published 53903 publications receiving 1641968 citations.

Fano-like interference in self-assembled plasmonic quadrumer clusters.

Abstract: Assemblies of strongly interacting metallic nanoparticles are the basis for plasmonic nanostructure engineering. We demonstrate that clusters of four identical spherical particles self-assembled into a close-packed asymmetric quadrumer support strong Fano-like interference. This feature is highly sensitive to the polarization of the incident electric field due to orientation-dependent coupling between particles in the cluster. This structure demonstrates how careful design of self-assembled colloidal systems can lead to the creation of new plasmonic modes and the enabling of interference effects in plasmonic systems.

Interlayer-expanded molybdenum disulfide nanocomposites for electrochemical magnesium storage

Abstract: Mg rechargeable batteries (MgRBs) represent a safe and high-energy battery technology but suffer from the lack of suitable cathode materials due to the slow solid-state diffusion of the highly polarizing divalent Mg ion. Previous methods improve performance at the cost of incompatibility with anode/electrolyte and drastic decrease in volumetric energy density. Herein we report interlayer expansion as a general and effective atomic-level lattice engineering approach to transform inactive intercalation hosts into efficient Mg storage materials without introducing adverse side effects. As a proof-of-concept we have combined theory, synthesis, electrochemical measurement, and kinetic analysis to improve Mg diffusion behavior in MoS2, which is a poor Mg transporting material in its pristine form. First-principles simulations suggest that expanded interlayer spacing allows for fast Mg diffusion because of weakened Mg-host interactions. Experimentally, the expansion was realized by inserting a controlled amount of poly(ethylene oxide) into the lattice of MoS2 to increase the interlayer distance from 0.62 nm to up to 1.45 nm. The expansion boosts Mg diffusivity by 2 orders of magnitude, effectively enabling the otherwise barely active MoS2 to approach its theoretical storage capacity as well as to achieve one of the highest rate capabilities among Mg-intercalation materials. The interlayer expansion approach can be leveraged to a wide range of host materials for the storage of various ions, leading to novel intercalation chemistry and opening up new opportunities for the development of advanced materials for next-generation energy storage.

Resistance to Brand Switching when a Radically New Brand is Introduced: A Social Identity Theory Perspective:

Abstract: There has been little research on how market disruptions affect customer–brand relationships and how firms can sustain brand loyalty when disruptions occur. Drawing from social identity theory and the brand loyalty literature, the authors propose a conceptual framework to examine these issues in a specific market disruption, namely, the introduction of a radically new brand. The framework focuses on the time-varying effects of customers' identification with and perceived value of the incumbent relative to the new brand on switching behavior. The authors divert from the conventional economic perspective of treating brand switching as functional utility maximization to propose that brand switching can also result from customers' social mobility between brand identities. The results from longitudinal data of 679 customers during the launch of the iPhone in Spain show that both relative customer–brand identification and relative perceived value of the incumbent inhibit switching behavior, but their e...

High thermal conductivity in cubic boron arsenide crystals.

Abstract: The high density of heat generated in power electronics and optoelectronic devices is a critical bottleneck in their application. New materials with high thermal conductivity are needed to effectively dissipate heat and thereby enable enhanced performance of power controls, solid-state lighting, communication, and security systems. We report the experimental discovery of high thermal conductivity at room temperature in cubic boron arsenide (BAs) grown through a modified chemical vapor transport technique. The thermal conductivity of BAs, 1000 ± 90 watts per meter per kelvin meter-kelvin, is higher than that of silicon carbide by a factor of 3 and is surpassed only by diamond and the basal-plane value of graphite. This work shows that BAs represents a class of ultrahigh-thermal conductivity materials predicted by a recent theory, and that it may constitute a useful thermal management material for high-power density electronic devices.

In Situ-DRIFTS Study of Selective Catalytic Reduction of NOx by NH3 over Cu-Exchanged SAPO-34

Abstract: The intrinsic mechanism of the selective catalytic reduction (SCR) reaction over a Cu-exchanged SAPO-34 catalyst at low temperature was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), coupled with mass spectrometry to measure inlet and outlet gas concentrations. The evolution of the surface intermediates, as well as the reactivity of NH3 with surface NOx species and NOx with surface NH3 species, was evaluated. In terms of NOx adsorption, surface nitrates and nitrites are the main NOx adsorption species at low temperature. When NO was exposed to the sample with NH3 preadsorbed, surface NH3 was not reactive because of the low surface coverage of nitrates and nitrites. However, the reactivity is significantly enhanced by the inclusion of O2 in the feed, which promotes an increase in the concentration of surface nitrates and nitrites. DRIFTS results also reveal that the low temperature SCR reaction involves the formation of an NH4NO3 intermediate and its subsequent red...