8 research outputs found

    Dynamic spin-lattice coupling and nematic fluctuations in NaFeAs

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    We use inelastic neutron scattering to study acoustic phonons and spin excitations in single crystals of NaFeAs, a parent compound of iron pnictide superconductors. NaFeAs exhibits a tetragonal-to-orthorhombic structural transition at Ts58T_s\approx 58 K and a collinear antiferromagnetic (AF) order at TN45T_N\approx 45 K. While longitudinal and out-of-plane transverse acoustic phonons behave as expected, the in-plane transverse acoustic phonons reveal considerable softening on cooling to TsT_s, and then harden on approaching TNT_N before saturating below TNT_N. In addition, we find that spin-spin correlation lengths of low-energy magnetic excitations within the FeAs layer and along the cc-axis increase dramatically below TsT_s, and show weak anomaly across TNT_N. These results suggest that the electronic nematic phase present in the paramagnetic tetragonal phase is closely associated with dynamic spin-lattice coupling, possibly arising from the one-phonon-two-magnon mechanism

    A Deformable Spatial Attention Mechanism-Based Method and a Benchmark for Dock Detection

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    Dock is a significant site in the shipbuilding industry. The detection of docks contributes to many important fields. With the abundant methods and datasets, the deep learning-based object detection in remote sensing images has received wide attention. However, there is no dataset that includes the dock class. This article first proposes a dock dataset to build a benchmark and advance dock detection research. Further, object detection of docks using existing methods cannot yield convincing results due to the characteristics of docks. To meet the challenges in dock detection, a novel deformable spatial attention module (DSAM) is proposed to enhance the feature representation and localization of docks. Based on the DSAM, a novel network architecture is proposed to perform accurate and efficient dock detection. The ablation and comparison experiments reveal that the proposed methods are accurate and effective, which are superior to the existing methods

    Rapid, Simultaneous, and Automatic Determination of Lead and Cadmium in Cereals with a New High Performance Composite Hollow Cathode Lamp Coupled to Graphite Furnace Atomic Absorption Spectrometry

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    A simple, rapid, sensitive, accurate, and automatic graphite furnace atomic absorption spectrometry (GFAAS) method for detecting Cd and Pb in cereals is presented. This method enables the simultaneous determination of Cd and Pb in cereals with a pre-treatment method of diluted acid extraction and a high-performance lead–cadmium composite hollow-cathode lamp (LCC-HCL), and it realizes automatic determination from sample weighing to result output through an automatic diluted acid extraction system. Under the optimization, Pb and Cd in cereals were simultaneously and automatically detected in up to 240 measurements in 8 h. The LOD and LOQ of this method were 0.012 and 0.040 mg·kg−1 for Pb, and 0.0014 and 0.0047 mg·kg−1 for Cd, respectively. The results of the four certified reference materials were satisfied; there was no significant difference compared with the ICP-MS method according to a t-test, and the RSDs were less than 5% for Cd and Pb. The recoveries of naturally contaminated samples compared with the ICP-MS method were favorable, with 80–110% in eight laboratories. The developed method is rapid, low-cost, and highly automated and may be a good choice for grain quality discrimination and rapid analysis of Cd and Pb in different institutions

    Erratum to: Performance evaluation of operational atmospheric correction algorithms over the East China Seas (Chinese Journal of Oceanology and Limnology, (2017), 35, 1, (1-22), 10.1007/s00343-016-5170-6)

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    Unfortunately for all articles of Vol. 35 No. 1 the future journal title “Journal of Oceanology and Limnology” was used instead of the current journal title “Chinese Journal of Oceanology and Limnology”. All articles in the issue are affected. Please make sure to cite the articles with the following Vol. and No. info: Chinese Journal of Oceanology and Limnology, Vol. 35 No. 1, [page range]

    Erratum to : Performance evaluation of operational atmospheric correction algorithms over the East China Seas (Chinese Journal of Oceanology and Limnology, (2017), 35, 1, (1-22), 10.1007/s00343-016-5170-6)

    No full text
    Unfortunately for all articles of Vol. 35 No. 1 the future journal title “Journal of Oceanology and Limnology” was used instead of the current journal title “Chinese Journal of Oceanology and Limnology”. All articles in the issue are aff ected. Please make sure to cite the articles with the following Vol. and No. info: Chinese Journal of Oceanology and Limnology, Vol. 35 No. 1, [page range]
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