Micron-size tab samples were ground using a high-intensity planetary ball mill at different milling times as an attempt to reduce particle size and study the effect on the corresponding hydrophobicity. XRD and SEM res...
Wide‐scale exploitation of renewable energy requires low‐cost efficient energy storage devices. The use of metal‐free, inexpensive redox‐active organic materials represents a promising direction for environmental...
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Wide‐scale exploitation of renewable energy requires low‐cost efficient energy storage devices. The use of metal‐free, inexpensive redox‐active organic materials represents a promising direction for environmental‐friendly, cost‐effective sustainable energy storage. To this end, a liquid battery is designed using hydroquinone (H 2 BQ) aqueous solution as catholyte and graphite in aprotic electrolyte as anode. The working potential can reach 3.4 V, with specific capacity of 395 mA h g −1 and stable capacity retention about 99.7 % per cycle. Such high potential and capacity is achieved using only C, H and O atoms as building blocks for redox species, and the replacement of Li metal with graphite anode can circumvent potential safety issues. As H 2 BQ can be extracted from biomass directly and its redox reaction mimics the bio‐electrochemical process of quinones in nature, using such a bio‐inspired organic compound in batteries enables access to greener and more sustainable energy‐storage technology.
The ultimate goal of multiferroic research is the development of new-generation non-volatile memory devices1, the so-called magnetoelectric (ME) memories, where magnetic bits are controlled via electric fields without...
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Avalanche photodiodes based on impact ionization can amplify optical signals, but the gain is associated with large excess noise and requires high bias near or above breakdown (for Geiger mode). Here we present a dete...
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Studies of superconductivity in multiband correlated electronic systems have become one of the central topics in condensed-matter and materials physics. In this paper, we present the results of thermodynamic measureme...
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Studies of superconductivity in multiband correlated electronic systems have become one of the central topics in condensed-matter and materials physics. In this paper, we present the results of thermodynamic measurements on the superconducting filled skutterudite system Pr1−xCexPt4Ge12 (0≤x≤0.2) to investigate how substitution of Ce at Pr sites affects superconductivity. We find that an increase in Ce concentration leads to a suppression of the superconducting transition temperature from Tc∼7.9 K for x=0 to Tc∼0.6 K for x=0.14. Our analysis of the specific-heat data for x≤0.07 reveals that superconductivity must develop in at least two bands: the superconducting order parameter has nodes on one Fermi pocket and remains fully gapped on the other. Both the nodal and nodeless gaps decrease, with the nodal gap being suppressed more strongly upon Ce substitution. Ultimately, the higher-Ce-concentration samples (x>0.07) display a nodeless gap only.
We report a study of the superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12−xSbx. Polycrystalline samples with Sb concentrations up to x=5 were synthesized and investigated by mean...
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We report a study of the superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12−xSbx. Polycrystalline samples with Sb concentrations up to x=5 were synthesized and investigated by means of x-ray diffraction, electrical resistivity, magnetic susceptibility, and specific heat measurements. We observed a suppression of superconductivity with increasing Sb substitution up to x=4, above which no signature of superconductivity was observed down to 140 mK. The Sommerfeld coefficient, γ, of superconducting specimens decreases with increasing x up to x=3, suggesting that superconductivity may depend on the density of electronic states in this system. The specific heat for x=0.5 exhibits an exponential temperature dependence in the superconducting state, reminiscent of a nodeless superconducting energy gap. We observed evidence for a weak “rattling” mode associated with the Pr ions, characterized by an Einstein temperature ΘE∼60 K for 0≤x≤5; however, the rattling mode may not play any role in suppressing superconductivity.
The microstructure of a material intimately affects the performance of a device made from this material. The microstructure, in turn, is affected by the processing pathway used to fabricate the device. This forms the ...
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The microstructure of a material intimately affects the performance of a device made from this material. The microstructure, in turn, is affected by the processing pathway used to fabricate the device. This forms the process–structure–property triangle that is central to material science. There has been increasing interest to comprehensively understand and subsequently exploit process–structure–property (PSP) relationships to design processing pathways that result in tailored microstructures exhibiting optimal properties. However, unraveling process–structure–property relationships usually requires systematic and tedious combinatorial search of process and system variables to identify the microstructures that are produced. This is further complicated by the necessity to interrogate the properties of the huge set of corresponding microstructures. Motivated by this challenge, we focus on developing a generic methodology to establish and explore PSP pathways. We leverage recent advances in high performance computing (HPC) and high throughput computing (HTC) with the premise that a domain expert should be able to focus on domain specific PSP problems while the highly specialized HPC/HTC knowledge needed to approach such problems should be hidden from the domain expert. Our hypothesis is that PSP exploration can be naturally formulated in terms of a standard paradigm in cloud computing, namely the MapReduce programming model. We show how reformulating PSP exploration into a MapReduce workflow enables us to take advantage of advances in cloud computing while requiring minimal specialized knowledge of HPC. We illustrate this generic approach by exploring PSP relationships relevant to organic photovoltaics. We focus on identifying microstructural traits that correlate with specific properties of the photovoltaic process: exciton generation, exciton dissociation and charge generation. We integrate a graph-based microstructure characterization tool, and a microstructure-aware
Web Service composition is a complex and error-prone process that requires the support of software tools in order to become feasible. Composition tools can help a developer to select compatible services from vast serv...
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