4,627 research outputs found
Explosive events associated with a surge
The solar atmosphere contains a wide variety of small-scale transient
features. Here, we explore the inter-relation between some of them such as
surges, explosive events and blinkers via simultaneous spectral and imaging
data taken with the TRACE imager, the SUMER, and CDS spectrometers on board
SoHO, and SVST La Palma. The alignment of all data both in time and solar XY
shows that SUMER line profiles, which are attributed to explosive events, are
due to a surge phenomenon. The surge is triggered, most probably, by one or
more Elerman bombs which are best visible in Halpha +-350 A but were also
registered by TRACE Fe IX/X 171 A and correspond to a strong radiance increase
in the CDS Mg IX 368.07 A line. With the present study we demonstrate that the
division of small-scale transient events into a number of different subgroups,
for instance explosive events, blinkers, spicules, surges or just brightenings,
is ambiguous, implying that the definition of a feature based only on either
spectroscopic or imaging characteristics as well as insufficient spectral and
spatial resolution can be incomplete.Comment: 17 pages, 7 figures, 1 tabl
Predictability of reset switching voltages in unipolar resistance switching
In unipolar resistance switching of NiO capacitors, Joule heating in the
conducting channels should cause a strong nonlinearity in the low resistance
state current-voltage (I-V) curves. Due to the percolating nature of the
conducting channels, the reset current IR, can be scaled to the nonlinear
coefficient Bo of the I-V curves. This scaling relationship can be used to
predict reset voltages, independent of NiO capacitor size; it can also be
applied to TiO2 and FeOy capacitors. Using this relation, we developed an error
correction scheme to provide a clear window for separating reset and set
voltages in memory operations
Putting Enterohemorrhagic E. coli on a Pedestal
Many pathogenic bacteria exploit host cytoskeletal pathways to promote infection. In this issue of Cell Host & Microbe, Weiss et al. (2009) identify the host factor IRSp53 as the missing link that connects two intracellular bacterial proteins, thereby completing an actin cytoskeletal signaling pathway critical to enterohemorrhagic Escherichia coli pathogenesis
Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2
An abrupt first-order metal-insulator transition (MIT) without structural
phase transition is first observed by current-voltage measurements and
micro-Raman scattering experiments, when a DC electric field is applied to a
Mott insulator VO_2 based two-terminal device. An abrupt current jump is
measured at a critical electric field. The Raman-shift frequency and the
bandwidth of the most predominant Raman-active A_g mode, excited by the
electric field, do not change through the abrupt MIT, while, they, excited by
temperature, pronouncedly soften and damp (structural MIT), respectively. This
structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure
Interfacial Issues and Modification of Solid Electrolyte Interphase for Li Metal Anode in Liquid and Solid Electrolytes
The high energy density required for the next generation of lithium batteries will likely be enabled by a shift toward lithium metal anode from the conventional intercalation-based anode such as graphite. However, several critical challenges for Li metal originate from its highly reactive nature and the hostless reaction of deposition and stripping impede the practical use of Li metal as an anode. The role of the solid electrolyte interphase (SEI) is very important for the Li metal anode where the SEI must protect the dynamically changing surface of the Li metal. Since the SEI-generating reaction mechanisms for the two different electrolyte systems, liquid and solid, are considerably different, the SEI layers formed between the Li metal and the electrolytes in the two electrolyte systems have substantially different properties, causing different interfacial issues. Inhibition of the interfacial problems requires different strategies to reinforce the SEI layer for each of the electrolyte systems. However, the differences in the two electrolyte systems have not been clearly compared in the prior literature. In this report, the interfacial issues for the two different electrolyte systems are compared and different strategies for SEI modification are provided to overcome the issues
Observational Signatures of Simulated Reconnection Events in the Solar Chromosphere and Transition Region
We present the results of numerical simulations of wave-induced magnetic
reconnection in a model of the solar atmosphere. In the magnetic field geometry
we study in this article, the waves, driven by a monochromatic piston and a
driver taken from Hinode observations, induce periodic reconnection of the
magnetic field, and this reconnection appears to help drive long-period
chromospheric jets. By synthesizing observations for a variety of wavelengths
that are sensitive to a wide range of temperatures, we shed light on the often
confusing relationship between the plethora of jet-like phenomena in the solar
atmosphere, e.g., explosive events, spicules, blinkers, and other phenomena
thought to be caused by reconnection.Comment: 13 pages, 22 figures. Submitted to The Astrophysical Journa
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