31 research outputs found
Nonvolatile CMOS memristor, reconfigurable array and its application in power load forecasting
© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This is the accepted manuscript version of a conference paper which has been published in final form at https://doi.org/10.1109/TII.2023.3341256The high cost, low yield, and low stability of nano-materials significantly hinder the application and development of memristors. To promote the application of memristors, researchers proposed a variety of memristor emulators to simulate memristor functions and apply them in various fields. However these emulators lack nonvolatile characteristics, limiting their scope of application. This paper proposes an innovative nonvolatile memristor circuit based on complementary metal-oxide-semiconductor (CMOS) technology, expanding the horizons of memristor emulators. The proposed memristor is fabricated in a reconfigurable array architecture using the standard CMOS process, allowing the connection between memristors to be altered by configuring the on-off state of switches. Compared to nano-material memristors, the CMOS nonvolatile memristor circuit proposed in this paper offers advantages of low manufacturing cost and easy mass production, which can promote the application of memristors. The application of the reconfigurable array is further studied by constructing an Echo State Network (ESN) for short-term load forecasting in the power system.Peer reviewe
Superconductivity in the vicinity of antiferromagnetic order in CrAs
One of the common features of unconventional, magnetically mediated
superconductivity as found in the heavy-fermions, high-transition-temperature
(high-Tc) cuprates, and iron pnictides superconductors is that the
superconductivity emerges in the vicinity of long-range antiferromagnetically
ordered state.[1] In addition to doping charge carriers, the application of
external physical pressure has been taken as an effective and clean approach to
induce the unconventional superconductivity near a magnetic quantum critical
point (QCP).[2,3] Superconductivity has been observed in a majority of 3d
transition-metal compounds,[4-9] except for the Cr- and Mn-based compounds in
the sense that the low-lying states near Fermi level are dominated by their 3d
electrons. Herein, we report on the discovery of superconductivity on the verge
of antiferromagnetic order in CrAs via the application of external high
pressure. Bulk superconductivity with Tc ~ 2 K emerges at the critical pressure
Pc ~ 8 kbar, where the first-order antiferromagnetic transition at TN = 265 K
under ambient pressure is completely suppressed. Abnormal normal-state
properties associated with a magnetic QCP have been observed nearby Pc. The
close proximity of superconductivity to an antiferromagnetic order suggests an
unconventional pairing mechanism for the superconducting state of CrAs. The
present finding opens a new avenue for searching novel superconductors in the
Cr and other transitional-metal based systems
Observation of Flat Band and Van Hove Singularity in Non-superconducting Nitrogen-doped Lutetium Hydride
Hydrogen-rich materials offer a compelling avenue towards room temperature
superconductivity, albeit under ultra-high pressure. However, the experimental
investigation of the electronic band structure remains elusive, due to the
inherent instability of most of the hydrogen-rich materials upon pressure
release. Very recently, nitrogen-doped lutetium hydride was claimed to host
room temperature superconductivity under near ambient pressure but was
disproven by following works. Upon decompression, nitrogen doped lutetium
hydride manifests a stable metallic phase with dark blue color. Moreover, high
temperature superconductivity has been reported in lutetium hydrides Lu4H23
(~71 K) under around 200 GPa. These properties engender an unprecedented
opportunity, allowing for the experimental investigation of the electronic band
structure intrinsic to hydrogen-rich material. In this work, using angle
resolved photoemission spectroscopy to investigate the non-superconducting
nitrogen doped lutetium hydride, we observed significant flat band and Van Hove
singularity marginally below the Fermi level. These salient features,
identified as critical elements, proffer potential amplifiers for the
realization of heightened superconductivity, as evidenced by prior research.
Our results not only unveil a confluence of potent strong correlation effects
and anisotropy within the Lu-H-N compound, but also provide a prospect for
engineering high temperature superconductivity through the strategic
manipulation of flat band and the VHS, effectively tailoring their alignment
with the Fermi energy.Comment: 26 pages, 9 figure
Chromosome-level genome assembly of a regenerable maize inbred line A188.
BACKGROUND
The maize inbred line A188 is an attractive model for elucidation of gene function and improvement due to its high embryogenic capacity and many contrasting traits to the first maize reference genome, B73, and other elite lines. The lack of a genome assembly of A188 limits its use as a model for functional studies.
RESULTS
Here, we present a chromosome-level genome assembly of A188 using long reads and optical maps. Comparison of A188 with B73 using both whole-genome alignments and read depths from sequencing reads identify approximately 1.1 Gb of syntenic sequences as well as extensive structural variation, including a 1.8-Mb duplication containing the Gametophyte factor1 locus for unilateral cross-incompatibility, and six inversions of 0.7 Mb or greater. Increased copy number of carotenoid cleavage dioxygenase 1 (ccd1) in A188 is associated with elevated expression during seed development. High ccd1 expression in seeds together with low expression of yellow endosperm 1 (y1) reduces carotenoid accumulation, accounting for the white seed phenotype of A188. Furthermore, transcriptome and epigenome analyses reveal enhanced expression of defense pathways and altered DNA methylation patterns of the embryonic callus.
CONCLUSIONS
The A188 genome assembly provides a high-resolution sequence for a complex genome species and a foundational resource for analyses of genome variation and gene function in maize. The genome, in comparison to B73, contains extensive intra-species structural variations and other genetic differences. Expression and network analyses identify discrete profiles for embryonic callus and other tissues
From One Environment to Many: The Problem of Reproducibility of Experimental Results
Master of ScienceDepartment of StatisticsMichael J. HigginsWhen the same experiment is carried out in a different environment, the error term not only includes the random error within a given experiment, but it also includes the additional sources of variability that are introduced by conducting the same experiment in different environments. These differences include both natural factors such as location, time or weather and other factors such as personnel or equipment necessary to carry out this experiment. By considering the effect of changing experimental environments on the reproducibility of experiments, we try to figure out in what situations the initial experimental results will likely carry over to other environments. We examine how p-value, effect size, sample size, and the ratio of the standard deviation of environment by treatment interaction and the standard deviation of experimental error interact with one another, and as a whole, affect the experiment's reproducibility. We suggest that not only p-values but also the effect sizes and the environmental effect ratio---the ratio of the standard deviation of environment by treatment interaction and the standard deviation of experimental error---should be considered when researchers are making statistical inferences. Large effect sizes and/or small ratios of the environmental effect ratio favor high probability of reproducibility. If the environmental effect ratio is too large, the reproducibility probability may be reduced to just a coin toss, and if effect sizes are small, researchers should be very cautious about making inferences about reproducibility even if the observed p-value is small and sample size is large
Surface Properties of Pine Scrimber Panels with Varying Density
Coating quality for scrimber products against exterior conditions is largely dependent on the surface properties. The wettability, morphology, and chemical composition of pine scrimber surfaces were investigated to better understand the surface properties. The scrimber was found to be a hydrophilic material because the water contact angles were less than 90°. The panels with a density of 1.20 g/cm3 had the largest angle change rate (k = 0.212). As the panel density increased, the instantaneous contact angle of each test liquid (i.e., water, formamide, and diiodomethane) on the panels decreased, and so did surface free energy. Panels with higher density showed lower surface roughness. Surface roughness across the wood grain was greater than that along the grain. SEM observations showed the high-density panels had a smoother surface with fewer irregular grooves in comparison with the low-density panels. X-ray photoelectron spectroscopy (XPS) analysis indicated that more unoxygenated groups appeared on the surface of high-density panels