12,030 research outputs found
Anomalous elasticity of nematic elastomers
We study the anomalous elasticity of nematic elastomers by employing the
powers of renormalized field theory. Using general arguments of symmetry and
relevance, we introduce a minimal Landau-Ginzburg-Wilson elastic energy for
nematic elastomers. Performing a diagrammatic low temperature expansion, we
analyze the fluctuations of the displacement fields at and below the upper
critical dimension 3. Our analysis reveals an anomaly of certain elastic moduli
in the sense that they depend on the length scale. In this dependence
is logarithmic and below it is of power law type with anomalous scaling
exponents. One of the 4 relevant shear moduli vanishes at long length scales
whereas the only relevant bending modulus diverges.Comment: 4 page
Fully gapped superconducting state in Au2Pb: a natural candidate for topological superconductor
We measured the ultra-low-temperature specific heat and thermal conductivity
of AuPb single crystal, a possible three-dimensional Dirac semimetal with a
superconducting transition temperature 1.05 K. The electronic
specific heat can be fitted by a two-band s-wave model, which gives the gap
amplitudes (0)/ = 1.38 and (0)/ = 5.25.
From the thermal conductivity measurements, a negligible residual linear term
in zero field and a slow field dependence of at low
field are obtained. These results suggest that AuPb has a fully gapped
superconducting state in the bulk, which is a necessary condition for
topological superconductor if AuPb is indeed one.Comment: 6 pages, 4 figure
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Thin Solid Electrolyte Layers Enabled by Nanoscopic Polymer Binding
To achieve high-energy all-solid-state batteries (ASSBs), solid-state electrolytes (SE) must be thin, mechanically robust, and possess the ability to form low resistance interfaces with electrode materials. Embedding an inorganic SE into an organic polymer combines the merits of high conductivity and flexibility. However, the performance of such an SE-in-polymer matrix (SEPM) is highly dependent on the microstructure and interactions between the organic and inorganic components. We report on the synthesis of a free-standing, ultrathin (60 μm) SEPM from a solution of lithium polysulfide, phosphorus sulfide, and ethylene sulfide (ES), where the polysulfide triggers the in situ polymerization of ES and the formation of Li3PS4. Reactant ratios were optimized to achieve a room-temperature conductivity of 2 × 10-5 S cm-1. Cryogenic electron microscopy confirmed a uniform nanoscopic distribution of β-Li3PS4 and PES (polyethylene sulfide). This work presents a facile route to the scalable fabrication of ASSBs with promising cycling performance and low electrolyte loading
Effect of 1-methylcyclopropene and modified atmosphere packaging on chilling injury and antioxidative defensive mechanism of sweet pepper
Some sweet peppers (Capsicum annuum L.) are chilling sensitive and can develop injury when stored at temperatures less than 7°C. This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP) (650 ppb) and modified atmosphere packaging (MAP) on chilling injuries (CI) of sweet pepper during 30 days storage at 4°C. The results showed that, 1-MCP and MAP reduced chilling injury symptoms which were correlated with decreased electrolyte leakage and malondialdehyde content. The combination of 1-MCP and MAP further reduced chilling injury. Atomic force microscope (AFM) images showed that, the surface of the sweet peppers with 1-MCP and MAP treatments were smoother than of the control samples. The activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) of sweet peppers were also influenced by 1-MCP and MAP. SOD, CAT and POD activities of sweet peppers were 87.3, 28.97 and 0.248 U·g-1, respectively at the beginning of the storage. The activities decreased during the first 15 days of storage followed by an increase during the later period of storage. Treatment with 1-MCP, MAP alone and in combination frequently reduced the activities of those enzymes during storage. These results suggested that, combination of 1-MCP treatment and MAP is a promising treatment for reducing chilling injuries of peppers stored at 4°C.Key words: 1-MCP, chilling injuries, modified atmosphere packaging, sweet pepper
Initiation and Early Kinematic Evolution of Solar Eruptions
We investigate the initiation and early evolution of 12 solar eruptions,
including six active region hot channel and six quiescent filament eruptions,
which were well observed by the \textsl{Solar Dynamics Observatory}, as well as
by the \textsl{Solar TErrestrial RElations Observatory} for the latter. The
sample includes one failed eruption and 11 coronal mass ejections, with
velocities ranging from 493 to 2140~km~s. A detailed analysis of the
eruption kinematics yields the following main results. (1) The early evolution
of all events consists of a slow-rise phase followed by a main-acceleration
phase, the height-time profiles of which differ markedly and can be best fit,
respectively, by a linear and an exponential function. This indicates that
different physical processes dominate in these phases, which is at variance
with models that involve a single process. (2) The kinematic evolution of the
eruptions tends to be synchronized with the flare light curve in both phases.
The synchronization is often but not always close. A delayed onset of the
impulsive flare phase is found in the majority of the filament eruptions (5 out
of 6). This delay, and its trend to be larger for slower eruptions, favor ideal
MHD instability models. (3) The average decay index at the onset heights of the
main acceleration is close to the threshold of the torus instability for both
groups of events (although based on a tentative coronal field model for the hot
channels), suggesting that this instability initiates and possibly drives the
main acceleration.Comment: Accepted for publication in ApJ; 24 pages, 12 figures, 3 table
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