Vanadium-based Nanomaterials for Improved Zn Ion Storage

Rechargeable aqueous zinc-ion batteries (ZIBs) have been intensively studied as novel promising large-scale energy storage systems recently, owing to their advantages of high abundance, cost effectiveness, and high safety. However, the development of suitable cathode materials with superior performance are severely hampered by the sluggish kinetics of Zn2+ with divalent charge in the host structure. Our Work demonstrates boosting the electrochemical performances of nanostructured cathode materials for aqueous ZIBs. The first project is focused on the interlayer-expanded V6O13∙nH2O nanosheets as promising cathodes. Benefiting from the synthetic merits of its favorable architecture and expanded interlamellar spacing resulted from its structural water, the V6O13∙nH2O cathode exhibits outstanding electrochemical performances with a high reversible capacity of 395 mAh g-1 at 0.1 A g-1, superior rate capability, and durable cycling stability with a capacity retention of 87% up to 1000 cycles. In addition, the reaction mechanism is significantly investigated in detail. Moreover, the second project is focused on the synthesis of NH4V3O8∙1.9H2O nanobelts and investigation of the electrochemical properties in aqueous and quasi-solid-state (QSS) ZIBs. When examined in aqueous ZIBs, this cathode material enables ultrafast Zn2+ diffusion and highly reversible process, exhibiting superior electrochemical performances with a high discharge capacity of 463 mAh g-1 at 0.1 A g-1, excellent rate capability (183 mAh g-1 even at 10 A g-1), and impressive cycling stability with a capacity retention of 81% after 2000 cycles maintaining a decent discharge capacity of 166 mAh g-1 at 10 A g-1. Furthermore, the NH4V3O8∙1.9H2O electrode can deliver a high energy density of 332 Wh kg-1 at a power density of 72 W kg-1 and maintain an energy density of 101 Wh kg-1 at a high power density of 5519 W kg-1. The NH4V4O10∙1.6H2O is also studied as cathode materials for aqueous ZIBs, showing inferior electrochemical properties when compared with NH4V3O8∙1.9H2O. In addition, the QSS flexible Zn/NH4V3O8∙1.9H2O battery is also studied, showing durable cycling performance and stable electrochemical properties under various bending states. The present studies demonstrate that the V6O13∙nH2O nanosheets and NH4V3O8∙1.9H2O nanobelts are emerging as high-potential cathode materials for rechargeable zinc-ion battery, and it sheds light on the rational design of novel cathodes for grid-scale energy storage devices

A Shoulder-Surfing Resistant Scheme Embedded in Traditional Passwords

Typing passwords is vulnerable to shoulder-surfing attacks. We proposed a shoulder-surfing resistant scheme embedded in traditional textual passwords in this study. With the proposed scheme, when the password field is on focus, a pattern appears in it as a hint to tell the user how to enter a password. Following the hint, the user needs to skip some characters while typing the password. The characters to be skipped are randomly selected so that an observer will not be able to see the whole password even if the authentication procedure was recorded. We evaluated the proposed scheme in a usability study. Compared to traditional passwords, our scheme achieved a similar level of accuracy while only required marginal additional time to authenticate users. Participants also expressed significantly higher acceptance of the new technique for security-sensitive applications and gave it significantly higher ratings in perceived security, shoulders-surfing resistance, camera-recording resistance, and guess-attack resistance

A Single-Handed Partial Zooming Technique for Touch-Screen Mobile Devices

Despite its ubiquitous use, the pinch zooming technique is not effective for one-handed interaction. We propose ContextZoom, a novel technique for single-handed zooming on touch-screen mobile devices. It allows users to specify any place on a device screen as the zooming center to ensure that the intended zooming target is always visible on the screen after zooming. ContextZoom supports zooming in/out a portion of a viewport, and provides a quick switch between the partial and whole viewports. We conducted an empirical evaluation of ContextZoom through a controlled lab experiment to compare ContextZoom and the Google maps’ single-handed zooming technique. Results show that ContextZoom outperforms the latter in task completion time and the number of discrete actions taken. Participants also reported higher levels of perceived effectiveness and overall satisfaction with ContextZoom than with the Google maps’ single-handed zooming technique, as well as a similar level of perceived ease of use

From Small to Big: Smartwatch Use in Mitigating COVID-19 – Understanding User Experience from Social Media Content Analysis

Smartwatches offer both functions and convenience that can have great potentials for technological interventions. Despite widespread discussion of technological interventions for COVID-19, smartwatch use has received little attention in the literature. This research aims to fill the literature gap by providing a broad understanding of smartwatch use for COVID-19 mitigation. We investigate smartwatch use through content analysis of the data collected from two social media platforms. The method allows us to draw on user experience beyond technological features and functions. In addition to functions, we also identified the concerns of using smartwatches for mitigating COVID-19. Furthermore, we uncovered both similarities and differences between the different social media platforms in terms of functions and concerns of smartwatch use. Our findings have implications for various stakeholders of the smartwatch technology and for mitigating the impact of the pandemic

Polyamorphic Transformations in Fe‐Ni‐C Liquids: Implications for Chemical Evolution of Terrestrial Planets

During the formation of the Earth’s core, the segregation of metallic liquids from silicate mantle should have left behind evident geochemical imprints on both the mantle and the core. Some distinctive geochemical signatures of the mantle‐derived rocks likely own their origin to the metal‐silicate differentiation of the primitive Earth, setting our planet apart from undifferentiated meteorites as well as terrestrial planets or moons isotopically and compositionally. Understanding the chemical evolution of terrestrial planetary bodies requires knowledge on properties of both liquid iron alloys and silicates equilibrating under physicochemical conditions pertinent to the deep magma ocean. Here we report experimental and computational results on the pressure‐induced structural evolution of iron‐nickel liquids alloyed with carbon. Our X‐ray diffraction experiments up to 7.3 gigapascals (GPa) demonstrate that Fe‐Ni (Fe90Ni10) liquids alloyed with 3 and 5 wt % carbon undergo a polyamorphic liquid structure transition at approximately 5 GPa. Corroborating the experimental observations, our first‐principles molecular dynamic calculations reveal that the structural transitions result from the marked prevalence of three‐atom face‐sharing polyhedral connections in the liquids at >5 GPa. The structure and polyamorphic transitions of liquid iron‐nickel‐carbon alloys govern their physical and chemical properties and may thus cast fresh light on the chemical evolution of terrestrial planets and moons.Key PointsThe X‐ray diffraction measurements reveal a liquid structure transition in the Fe‐Ni‐C liquids at ~5 GPaCalculations show that the nature of the liquid transition is the favoring of three‐atom motifs connections in the high‐pressure liquids at >5 GPaThe structural change may affect the physicochemical properties of the liquids, influencing the chemical evolution of terrestrial bodiesPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141684/1/jgrb52447_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141684/2/jgrb52447-sup-0001-Data_S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141684/3/jgrb52447.pd

A Thumb Stroke-Based Virtual Keyboard for Sight-Free Text Entry on Touch-Screen Mobile Phones

The use of QWERTY on most of the current mobile devices for text entry usually requires users’ full visual attention and both hands, which is not always possible due to situational or physical impairments of users. Prior research has shown that users prefer to hold and interact with a mobile device with a single hand when possible, which is challenging and poorly supported by current mobile devices. We propose a novel thumb-stroke based keyboard called ThumbStroke, which can support both sight-free and one-handed text entry on touch-screen mobile devices. Selecting a character for text entry via ThumbStroke completely relies on the directions of thumb movements at anywhere on a device screen. We evaluated ThumbStroke through a longitudinal lab experiment including 20 sessions with 13 participants. ThumbStroke shows advantages in typing accuracy and user perceptions in comparison to Escape and QWERTY and results in faster typing speed than QWERTY for sight-free text entry

Drell-Yan Massive Lepton-Pair's Angular Distributions at Large QTQ_T

By measuring Drell-Yan massive lepton-pair's angular distributions, we can identify the polarization of the virtual photon of invariant mass $Q$ which decays immediately into the lepton-pair. In terms of a modified QCD factorization formula for Drell-Yan process, which is valid even if $Q_T\gg Q$, we calculate the massive lepton-pair's angular distributions at large $Q_T$. We find that the virtual photons produced at high $Q_T$ are more likely to be transversely polarized. We discuss the implications of this finding to the J/$\psi$ mesons' polarization measured recently at Fermilab.Comment: Latex, 10 pages including 4 figure

Microporous organic polymers based on hexaphenylbiadamantane:synthesis, ultra-high stability and gas capture

Hexaphenylbiadamantane-based microporous organic polymers (MOPs) were successfully synthesized by Suzuki coupling under mild conditions. The obtained MOPs show high surface area (891 m2 g−1), ultra-high thermal (less than 40% mass loss at temperatures up to 1000 °C) and chemical (no apparent decomposition in organic solvents for more than 7 days) stability, gas (H2, CO2, CH4) capture capabilities and vapor (benzene, hexane) adsorption. These combined abilities render the synthesized MOPs an attractive candidate as thermo-chemically stable adsorbents for practical use in gas storage and pollutant vapor adsorption

Nonlinear corrections to the DGLAP equations in view of the HERA data

The effects of the first nonlinear corrections to the DGLAP evolution equations are studied by using the recent HERA data for the structure function $F_2(x,Q^2)$ of the free proton and the parton distributions from CTEQ5L and CTEQ6L as a baseline. By requiring a good fit to the H1 data, we determine initial parton distributions at $Q_0^2=1.4$ GeV$^2$ for the nonlinear scale evolution. We show that the nonlinear corrections improve the agreement with the $F_2(x,Q^2)$ data in the region of $x\sim 3\cdot 10^{-5}$ and $Q^2\sim 1.5$ GeV$^2$ without paying the price of obtaining a worse agreement at larger values of $x$ and $Q^2$. For the gluon distribution the nonlinear effects are found to play an increasingly important role at x\lsim 10^{-3} and Q^2\lsim10 GeV$^2$, but rapidly vanish at larger values of $x$ and $Q^2$. Consequently, contrary to CTEQ6L, the obtained gluon distribution at $Q^2=1.4$ GeV$^2$ shows a power-like growth at small $x$. Relative to the CTEQ6L gluons, an enhancement up to a factor $\sim6$ at $x=10^{-5}$, $Q_0^2=1.4$ GeV$^2$ reduces to a negligible difference at Q^2\gsim 10 GeV$^2$.Comment: 13 pages, 5 eps-figures; revision: references added, Fig. 3 revise