307 research outputs found
Advantages and developments of Raman spectroscopy for electroceramics
Despite being applied with success in many fields of materials science, Raman
spectroscopy is not yet determinant in the study of electroceramics. Recent
experimental and theoretical developments, however, should increase the
popularity of Raman spectroscopy in this class of materials. In this Review, we
outline the fields of application of Raman spectroscopy and microscopy in
various electroceramic systems, defining current key bottlenecks and explaining
promising recent developments. We focus our attention to recent experimental
developments, including coupling Raman spectroscopy with other methodologies,
and modelling approaches involving both the model-based data interpretation and
the ab initio calculation of realistic Raman spectra
Virtual screening of the inhibitors targeting at the viral protein 40 of Ebola virus
Multilingual abstracts in the six official working languages of the United Nations. (PDF 373 kb
De-Pinning Transition of Bubble Phases in a High Landau Level
While in the lowest Landau level the electron-electron interaction leads to
the formation of the Wigner crystal, in higher Landau levels a solid phase with
multiple electrons in a lattice site of crystal was predicted, which was called
the bubble phase. Reentrant integer quantum Hall states are believed to be the
insulating bubble phase pinned by disorder. We carry out nonlinear transport
measurements on the reentrant states and study the de-pinning of the bubble
phase, which is complementary to previous microwave measurements and provides
unique information. In this study, conductivity is directly measured with
Corbino geometry. Based on the threshold electric field of de-pinning, a phase
diagram of the reentrant state is mapped. We discuss an interaction-driven
topological phase transition between the integer quantum Hall state and the
reentrant integer quantum Hall state.Comment: 11 pages, 3 figure
Development on a high-beam-transparency gridded electron gun based on a carbon nanotube cold cathode
Anomalous quantized plateaus in two-dimensional electron gas with gate confinement
Quantum information can be coded by the topological protected edges of
fractional quantum Hall (FQH) states. Investigation on FQH edges in the hope of
searching and utilizing non-Abelian statistics has been a focused challenge for
years. Manipulating the edges, e.g. to bring edges close to each other or to
separate edges spatially, is a common and essential step for such studies. The
FQH edge structures in a confined region are typically presupposed to be the
same as that in the open region in analysis of experimental results, but
whether they remain unchanged with extra confinement is obscure. In this work,
we present a series of unexpected plateaus in a confined single-layer
two-dimensional electron gas (2DEG), which are quantized at anomalous fractions
such as 3/2, 9/4, 17/11 and 16/13. We explain all the plateaus by assuming
surprisingly larger filling factors in the confined region, and determine the
edge structures of FQH states with and without confinement together simply from
the quantization value. The information of the 5/2, 5/3, 8/5 and 7/5 FQH edge
modes in the dimension of ~1 micron have been probed, which is crucial for the
experiments with quantum point contact and interferometer.Comment: 13 pages, 4 figures + 9 pages, 4 figure
Asymptotic Behavior of Ext functors for modules of finite complete intersection dimension
Let be a local ring, and let and be finitely generated
-modules such that has finite complete intersection dimension. In this
paper we define and study, under certain conditions, a pairing using the
modules \Ext_R^i(M,N) which generalizes Buchweitz's notion of the Herbrand
diference. We exploit this pairing to examine the number of consecutive
vanishing of \Ext_R^i(M,N) needed to ensure that \Ext_R^i(M,N)=0 for all
. Our results recover and improve on most of the known bounds in the
literature, especially when has dimension at most two
Parameter selection of Gaussian kernel SVM based on local density of training set
Support vector machine (SVM) is regarded as one of the most effective techniques for supervised learning, while the Gaussian kernel SVM is widely utilized due to its excellent performance capabilities. To ensure high performance of models, hyperparameters, i.e. kernel width and penalty factor must be determined appropriately. This paper studies the influence of hyperparameters on the Gaussian kernel SVM when such hyperparameters attain an extreme value (0 or ∞). In order to improve computing efficiency, a parameter optimization method based on the local density and accuracy of Leave-One-Out (LOO) method are proposed. Kernel width of each sample is determined based on the local density needed to ensure a higher separability in feature space while the penalty parameter is determined by an improved grid search using the LOO method. A comparison with grid method is conducted to verify validity of the proposed method. The classification accuracy of five real-life datasets from UCI database are 0.9733, 0.9933, 0.7270, 0.6101 and 0.8867, which is slightly superior to the grid method. The results also demonstrate that this proposed method is computationally cheaper by 1 order of magnitude when compared to the grid method
Induced proximity of a TIR signaling domain on a plant-mammalian NLR chimera activates defense in plants
Plant and animal intracellular nucleotide-binding, leucine-rich repeat (NLR) immune receptors detect pathogen-derived molecules and activate defense. Plant NLRs can be divided into several classes based upon their N-terminal signaling domains, including TIR (Toll-like, Interleukin-1 receptor, Resistance protein)- and CC (coiled-coil)-NLRs. Upon ligand detection, mammalian NAIP and NLRC4 NLRs oligomerize, forming an inflammasome that induces proximity of its N-terminal signaling domains. Recently, a plant CC-NLR was revealed to form an inflammasome-like hetero-oligomer. To further investigate plant NLR signaling mechanisms, we fused the N-terminal TIR domain of several plant NLRs to the N terminus of NLRC4. Inflammasome-dependent induced proximity of the TIR domain in planta initiated defense signaling. Thus, induced proximity of a plant TIR domain imposed by oligomerization of a mammalian inflammasome is sufficient to activate authentic plant defense. Ligand detection and inflammasome formation is maintained when the known components of the NLRC4 inflammasome is transferred across kingdoms, indicating that NLRC4 complex can robustly function without any additional mammalian proteins. Additionally, we found NADase activity of a plant TIR domain is necessary for plant defense activation, but NADase activity of a mammalian or a bacterial TIR is not sufficient to activate defense in plants
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