Quasiparticle states around a nonmagnetic impurity in electron-doped iron-based superconductors with spin-density-wave order

The quasiparticle states around a nonmagnetic impurity in electron-doped iron-based superconductors with spin-density-wave (SDW) order are investigated as a function of doping and impurity scattering strength. In the undoped sample, where a pure SDW state exists, two impurity-induced resonance peaks are observed around the impurity site and they are shifted to higher (lower) energies as the strength of the positive (negative) scattering potential (SP) is increased. For the doped samples where the SDW order and the superconducting order coexist, the main feature is the existence of sharp in-gap resonance peaks whose positions and intensity depend on the strength of the SP and the doping concentration. In all cases, the local density of states exhibits clear $C_2$ symmetry. We also note that in the doped cases, the impurity will divide the system into two sublattices with distinct values of magnetic order. Here we use the band structure of a two-orbital model, which considers the asymmetry of the As atoms above and below the Fe-Fe plane. This model is suitable to study the properties of the surface layers in the iron-pnictides and should be more appropriate to describe the scanning tunneling microscopy experiments.Comment: 11 pages, 18 figure

Recent Advances in Ambipolar Transistors for Functional Applications

Ambipolar transistors represent a class of transistors where positive (holes) and negative (electrons) charge carriers both can transport concurrently within the semiconducting channel. The basic switching states of ambipolar transistors are comprised of common offâ state and separated onâ state mainly impelled by holes or electrons. During the past years, diverse materials are synthesized and utilized for implementing ambipolar charge transport and their further emerging applications comprising ambipolar memory, synaptic, logic, and lightâ emitting transistors on account of their special bidirectional carrierâ transporting characteristic. Within this review, recent developments of ambipolar transistor field involving fundamental principles, interface modifications, selected semiconducting material systems, device structures, ambipolar characteristics, and promising applications are highlighted. The existed challenges and prospective for researching ambipolar transistors in electronics and optoelectronics are also discussed. It is expected that the review and outlook are well timed and instrumental for the rapid progress of academic sector of ambipolar transistors in lighting, display, memory, as well as neuromorphic computing for artificial intelligence.Ambipolar transistors represent transistors that allow synchronous transport of electrons and holes and their accumulation within semiconductors. This review provides a comprehensive summary of recent advances in various semiconducting materials realized in ambipolar transistors and their functional memory, synapse, logic, as well as lightâ emitting applications.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151885/1/adfm201902105_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151885/2/adfm201902105.pd

A Summary Review of Correlations between Temperatures and Vibration Properties of Long-Span Bridges

The shift of modal parameters induced by temperature fluctuation may mask the changes of vibration properties caused by structural damage and result in false structural condition identification. Thoroughly understanding the temperature effects on vibration properties of long-span bridges becomes an especially important issue before vibration-based damage detection methodologies are applied in real bridges. This paper presents an overview of current research activities and developments in the field of correlations between temperatures and vibration properties of long-span bridges. The theoretical derivation methods using classical structural dynamics and closed-form formulations are first briefly introduced. Then the trend analysis methods that are intended to extract the degree of variability in vibration property under temperature variation for different bridges by numerical analysis, laboratory test, or field monitoring are reviewed in detail. Following that, the development of quantitative models to quantify the temperature influence on vibration properties is discussed including the linear model, nonlinear model, and learning model. Finally, some promising research efforts for promoting the study of correlations between temperatures and vibration properties of long-span bridges are suggested

Isolation, identification and complete genome sequence analysis of a strain of foot-and-mouth disease virus serotype Asia1 from pigs in southwest of China

Abstract Backgroud Foot-and-mouth disease virus (FMDV) serotype Asia1 generally infects cattle and sheep, while its infection of pigs is rarely reported. In 2005-2007, FMD outbreaks caused by Asia1 type occurred in many regions of China, as well as some parts of East Asia countries. During the outbreaks, there was not any report that pigs were found to be clinically infected. Results In this study, a strain of FMDV that isolated from pigs was identified as serotype Asia1, and designated as "Asia1/WHN/CHA/06". To investigate the genomic feature of the strain, complete genome of Asia1/WHN/CHA/06 was sequenced and compared with sequences of other FMDVs by phylogenetic and recombination analysis. The complete genome of Asia1/WHN/CHA/06 was 8161 nucleotides (nt) in length, and was closer to JS/CHA/05 than to all other strains. Potential recombination events associated with Asia1/WHN/CHA/06 were found between JS/CHA/05 and HNK/CHA/05 strains with partial 3B and 3C fragments. Conclusion This is the first report of the isolation and identification of a strain of FMDV type Asia1 from naturally infected pigs. The Asia1/WHN/CHA/06 strain may evolve from the recombination of JS/CHA/05 and HNK/CHA/05 strains.</p