128 research outputs found

    Anderson Localization from Berry-Curvature Interchange in Quantum Anomalous Hall System

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    We theoretically investigate the localization mechanism of the quantum anomalous Hall effect (QAHE) in the presence of spin-flip disorders. We show that the QAHE keeps quantized at weak disorders, then enters a Berry-curvature mediated metallic phase at moderate disorders, and finally goes into the Anderson insulating phase at strong disorders. From the phase diagram, we find that at the charge neutrality point although the QAHE is most robust against disorders, the corresponding metallic phase is much easier to be localized into the Anderson insulating phase due to the \textit{interchange} of Berry curvatures carried respectively by the conduction and valence bands. At the end, we provide a phenomenological picture related to the topological charges to better understand the underlying physical origin of the QAHE Anderson localization.Comment: 6 pages, 4 figure

    Erythritol attenuates postprandial blood glucose by inhibiting α-glucosidase

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    This work was supported by grants from Natural Science Foundation of Qinghai (No. 2016-ZJ-942Q), West Light Foundation of the Chinese Academy of Sciences (No. Y629071211), National Natural Science Foundation of China (No. 31701243), International Cooperative Projects of Qinghai province (No. 2017-HZ-811), Project of Discovery, Evaluation and Transformation of Active Natural Compounds, Strategic Biological Resources Service Network Program of Chinese Academy of Sciences (No. ZSTH-027), Major Special Science and Technology Projects in Qinghai Province (2014-GX-A3A-01).Diabetes mellitus (DM) is a serious metabolic disorder where impaired postprandial blood glucose regulation often leads to severe health complications. The natural chemical, erythritol is a C4 polyol approved by FDA for use as a sweetener. Here we examined a potential role for erythritol in the control of postprandial blood glucose levels in DM. An anti-postprandial hyperglycemia effect upon erythritol administration (500 mg kg-1) was demonstrated in alloxan-induced DM model mice by monitoring changes in blood glucose after intragastric administration of drugs and starch. We also found that erythritol most likely exerts its anti-postprandial hyperglycemic activities by inhibiting α-glucosidase in a competitive manner. This was supported by enzyme activity assays and molecular modelling experiments. In the latter experiments it was possible to successful dock erythritol into the catalytic pocket of α-glucosidase, with the resultant interaction likely to be driven by electrostatic interactions involving Asp 215, Asp69 and Arg446 residues. This study suggests that erythritol may not only serve as a glucose substitute but may also be a useful agent in the treatment of diabetes mellitus to help manage postprandial blood glucose levels.PostprintPeer reviewe

    Prostate Volumes Derived From MRI and Volume-Adjusted Serum Prostate-Specific Antigen: Correlation With Gleason Score of Prostate Cancer

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    The purpose of this article is to study relationships between MRI-based prostate volume and volume-adjusted serum prostate-specific antigen (PSA) concentration estimates and prostate cancer Gleason score

    The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125

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    We report on multi-wavelength observations, ranging from the X-ray to radio wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic observations reveal the presence of absorption lines due to O I, Si II, and C IV, implying a likely redshift of z = 1.547. The well-sampled light curves, in particular from 0.5 to 4 days after the burst, suggest a jet break at 3.7 days, corresponding to a jet opening angle of ~7.0 degrees, and implying an intrinsic GRB energy in the 1 - 10,000 keV band of around E = (6.3 - 6.9)x 10^(51) erg (based on the fluences measured by the gamma-ray detectors of the IPN network). GRB 070125 is among the brightest afterglows observed to date. The spectral energy distribution implies a host extinction of Av < 0.9 mag. Two rebrightening episodes are observed, one with excellent time coverage, showing an increase in flux of 56% in ~8000 seconds. The evolution of the afterglow light curve is achromatic at all times. Late-time observations of the afterglow do not show evidence for emission from an underlying host galaxy or supernova. Any host galaxy would be subluminous, consistent with current GRB host-galaxy samples. Evidence for strong Mg II absorption features is not found, which is perhaps surprising in view of the relatively high redshift of this burst and the high likelihood for such features along GRB-selected lines of sight.Comment: 50 pages, 9 figures, 5 tables Accepted to the Astrophysical Journa

    What Is Affecting the Popularity of New Energy Vehicles? A Systematic Review Based on the Public Perspective

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    The dependence of traditional fuel vehicles on petroleum energy has aggravated the energy crisis, while the harmful gas emissions generated during the use of traditional fuel vehicles have aggravated environmental pollution and climate warming. Therefore, it is urgent to alleviate energy consumption and environmental pollution in the transportation sector. The development and promotion of energy-saving and environmentally friendly new energy vehicles has become an important initiative in the world automotive industry. However, there is still a gap between the promotion of new energy vehicles and the public’s purchase preference, and understanding and respecting the public’s purchase preference can help promote the popularity of new energy vehicles. Based on the core database of the Web of Science, we extracted 1498 papers related to the public’s purchase preference and the popularization of new energy vehicles in the past two decades. We adopted a systematic literature review framework to clarify the research trajectory and research hotspots from literature combing, with the aim to reveal the interaction between the popularity of new energy vehicles and the public’s purchase preference. In addition, we further refined and summarized the existing major studies in order to provide solution ideas for achieving the transition to new energy vehicles in an effort to promote the green and sustainable development of energy

    COSY: COunterfactual SYntax for Cross-Lingual Understanding

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    Effective In-vehicle Intrusion Detection via Multi-view Statistical Graph Learning on CAN Messages

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    As an important component of internet of vehicles (IoV), intelligent connected vehicles (ICVs) have to communicate with external networks frequently. In this case, the resource-constrained in-vehicle network (IVN) is facing a wide variety of complex and changing external cyber-attacks, especially the masquerade attack with high difficulty of detection while serious damaging effects that few counter measures can identify successfully. Moreover, only coarse-grained recognition can be achieved in current mainstream intrusion detection mechanisms, i.e., whether a whole data flow observation window contains attack labels rather than fine-grained recognition on every single data item within this window. In this paper, we propose StatGraph: an Effective Multi-view Statistical Graph Learning Intrusion Detection to implement the fine-grained intrusion detection. Specifically, StatGraph generates two statistical graphs, timing correlation graph (TCG) and coupling relationship graph (CRG), based on data streams. In given message observation windows, edge attributes in TCGs represent temporal correlation between different message IDs, while edge attributes in CRGs denote the neighbour relationship and contextual similarity. Besides, a lightweight shallow layered GCN network is trained based graph property of TCGs and CRGs, which can learn the universal laws of various patterns more effectively and further enhance the performance of detection. To address the problem of insufficient attack types in previous intrusion detection, we select two real in-vehicle CAN datasets that cover four new attacks never investigated before. Experimental result shows StatGraph improves both detection granularity and detection performance over state-of-the-art intrusion detection methods.Comment: 14 pages, 8 figures, 6 tables, 27 reference

    Social-Aware Resource Allocation for Device-to-Device Communications Underlaying Cellular Networks

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    Improving Efficiency by Hybrid TiO2 Nanorods with 1,10-Phenanthroline as A Cathode Buffer Layer for Inverted Organic Solar Cells

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    We reported a significant improvement in the efficiency of organic solar cells by introducing hybrid TiO2:1,10-phenanthroline as a cathode buffer layer. The devices based on polymer thieno[3,4-b]thiophene/benzodithiophene:[6,6]-phenyl C-71-butyric acid methyl ester (PTB7:PC71BM) with hybrid buffer layer exhibited an average power conversion efficiency (PCE) as high as 8.02%, accounting for 20.8% enhancement compared with the TiO2 based devices. The cathode modification function of this hybrid material could also be extended to the poly(3-hexylthiophene):[6,6]-phenyl-C-61-butyric acid methyl ester (P3HT:PC61BM) system. We anticipate that this study will stimulate further research on hybrid materials to achieve more efficient charge collection and device performance

    Investigating the confining compressibility of STF at high deformation rate

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    The split Hopkinson pressure bar (SHPB) was used to study the compressibility of shear thickening fluid (STF) at high deformation rate. In this study, a steel bulk was introduced into the SHPB system to confine and load the STF. A series of STFs with different particle types (SiO2 and PSt-EA) and volume fractions (63 vol.% and 65 vol.%) were tested and the results were compared. The reliability of the results was proved by repeating the tests and the force balance in suspension. The bulk modulus was used to evaluate the compressibility of STF, which indicated that the SiO2-based STF exhibited a larger compressibility than the PSt-EA-based STF. It was found that the bulk modulus increases with increasing of the strain rate and the volume fraction shows little effect on the bulk modulus. The structure-dependent mechanical property was analyzed and the loading effect of bulk modulus was considered to be originated from the interparticle clustering
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