296 research outputs found

    DFPENet-geology: A Deep Learning Framework for High Precision Recognition and Segmentation of Co-seismic Landslides

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    The following lists two main reasons for withdrawal for the public. 1. There are some problems in the method and results, and there is a lot of room for improvement. In terms of method, "Pre-trained Datasets (PD)" represents selecting a small amount from the online test set, which easily causes the model to overfit the online test set and could not obtain robust performance. More importantly, the proposed DFPENet has a high redundancy by combining the Attention Gate Mechanism and Gate Convolution Networks, and we need to revisit the section of geological feature fusion, in terms of results, we need to further improve and refine. 2. arXiv is an open-access repository of electronic preprints without peer reviews. However, for our own research, we need experts to provide comments on my work whether negative or positive. I then would use their comments to significantly improve this manuscript. Therefore, we finally decided to withdraw this manuscript in arXiv, and we will update to arXiv with the final accepted manuscript to facilitate more researchers to use our proposed comprehensive and general scheme to recognize and segment seismic landslides more efficiently.Comment: 1. There are some problems in the method and results, and there is a lot of room for improvement. Overall, the proposed DFPENet has a high redundancy by combining the Attention Gate Mechanism and Gate Convolution Networks, and we need to further improve and refine the results. 2. For our own research, we need experts to provide comments on my work whether negative or positiv

    Towards Privacy-Preserving Person Re-identification via Person Identify Shift

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    Recently privacy concerns of person re-identification (ReID) raise more and more attention and preserving the privacy of the pedestrian images used by ReID methods become essential. De-identification (DeID) methods alleviate privacy issues by removing the identity-related of the ReID data. However, most of the existing DeID methods tend to remove all personal identity-related information and compromise the usability of de-identified data on the ReID task. In this paper, we aim to develop a technique that can achieve a good trade-off between privacy protection and data usability for person ReID. To achieve this, we propose a novel de-identification method designed explicitly for person ReID, named Person Identify Shift (PIS). PIS removes the absolute identity in a pedestrian image while preserving the identity relationship between image pairs. By exploiting the interpolation property of variational auto-encoder, PIS shifts each pedestrian image from the current identity to another with a new identity, resulting in images still preserving the relative identities. Experimental results show that our method has a better trade-off between privacy-preserving and model performance than existing de-identification methods and can defend against human and model attacks for data privacy

    Direct observation of structure-assisted filament splitting during ultrafast multiplepulse laser ablation

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    Laser-induced plasma evolution in fused silica through multipulse laser ablation was studied using pump-probe technology. Filament splitting was observed in the early stage of plasma evolution (before ~300 fs). This phenomenon can be attributed to competition between laser divergent propagation induced by a pre-pulse-induced crater and the nonlinear self-focusing effect. This effect was validated through simulation results. With the increasing pulse number, the appearance of filament peak electron density was postponed. Furthermore, a second peak in the filament and peak position separation were observed because of an optical path difference between the lasers propagating from the crater center and edge. The experimental results revealed the influence of a prepulse-induced structure on the energy distribution of subsequent pulses, which are essential for understanding the mechanism of laser–material interactions, particularly in ultrafast multiple-pulse laser ablation

    Control of earth-like magnetic fields on the transformation of ferrihydrite to hematite and goethite

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    Hematite and goethite are the two most abundant iron oxides in natural environments. Their formation is controlled by multiple environmental factors; therefore, their relative concentration has been used widely to indicate climatic variations. In this study, we aimed to test whether hematite and goethite growth is influenced by ambient magnetic fields of Earth-like values. Ferrihydrite was aged at 95 °C in magnetic fields ranging from ~0 to ~100 μT. Our results indicate a large influence of the applied magnetic field on hematite and goethite growth from ferrihydrite. The synthesized products are a mixture of hematite and goethite for field intensities <~60 μT. Higher fields favour hematite formation by accelerating ferrimagnetic ferrihydrite aggregation. Additionally, hematite particles growing in a controlled magnetic field of ~100 μT appear to be arranged in chains, which may be reduced to magnetite keeping its original configuration, therefore, the presence of magnetic particles in chains in natural sediments cannot be used as an exclusive indicator of biogenic magnetite. Hematite vs. goethite formation in our experiments is influenced by field intensity values within the range of geomagnetic field variability. Thus, geomagnetic field intensity could be a source of variation when using iron (oxyhydr-)oxide concentrations in environmental magnetism.This study was supported by the National Natural Science Foundation of China (grants 41504055, 41430962, 41374073, and 41025013). Z.X.J. further acknowledges support from the China Postdoctoral Science Foundation. A.P.R. acknowledges support from the Australian Research Council (grants DP110105419 and DP120103952)

    Controllable Plasmonic Nanostructures induced by Dual-wavelength Femtosecond Laser Irradiation

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    We demonstrated an abnormal double-peak (annular shaped) energy deposition through dualwavelength synthesis of the fundamental frequency (ω) and the second-harmonic frequency (2ω) of a femtosecond (fs) Ti:sapphire laser. The annular shaped distribution of the dual-wavelength fs laser was confirmed through real beam shape detection. This uniquely simple and flexible technique enables the formation of functional plasmonic nanostructures. We applied this double-peak fs-laser-induced dewetting effect to the controlled fabrication and precise deposition of Au nanostructures, by using a simple, lithography-free, and single-step process. In this process, the double-peak energy-shaped fs laser pulse induces surface patterning of a thin film followed by nanoscale hydrodynamic instability, which is highly controllable under specific irradiation conditions. Nanostructure morphology (shape, size, and distribution) modulation can be achieved by adjusting the laser irradiation parameters, and the subsequent ion-beam polishing enables further dimensional reduction and removal of the surrounding film. The unique optical properties of the resulting nanostructure are highly sensitive to the shape and size of the nanostructure. In contrast to a nanoparticle, the resonance-scattering spectrum of an Au nanobump exhibites two resonance peaks. These suggest that the dual-wavelength fs laserbased dewetting of thin films can be an effective means for the scalable manufacturing of patterned functional nanostructures

    Estimating the concentration of aluminum-substituted hematite and goethite using diffuse reflectance spectrometry and rock magnetism: Feasibility and limitations

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    Hematite and goethite in soils are often aluminum(Al) substituted, which can dramatically change their and magnetic properties and bias abundance estimates using diffuse reflectance spectroscopy (DRS) and magnetic techniques. In this study, synthetic Al-substituted hematites and goethites and two Chinese loess/paleosol sequences were investigated to test the feasibility and limitations of estimating Al-hematite and Al-goethite concentration. When Al substitution is limited (Al/(Al+ Fe) molar ratio<~8%), the reflectance spectrumprovides a reliable estimate of the goethite/hematite concentration ratio. New empirical relationships between the DRS band intensity ratio and the true concentration goethite/hematite ratio are estimated as goethite/hematite= 1.56 × (I₄₂₅ nm/I₅₃₅ nm) or goethite/hematite= 6.32 × (I₄₈₀ nm/I₅₃₅ nm), where I₄₂₅ nm, I₄₈₀ nm, and I₅₃₅ nm are the amplitudes of DRS second-derivative curves for characteristic bands at ~425 nm, ~480 nm, and ~535 nm, respectively. High Al substitution (> ~8%) reduces DRS band intensity, which leads to biased estimates of mineral concentration. Al substitution and grain size exert a control on coercivity distributions of hematite and goethite and, thus, affect the hard isothermal remanent magnetization. By integrating DRS and magneticmethods, we suggest a way to constrain hematite and goethite Al substitution in natural loess. Results indicate that hematite and goethite in Chinese loess have Al contents lower than ~8% and, thus, that DRS can be used to trace hematite and goethite concentration variations.This study was supported by the National Natural Science Foundation of China (41374073 and 41430962), the National Program on Global Changes and Air-Sea Interaction (GASI-04-01-02), and the Chinese Continental Shelf Deep Drilling Program (GZH201100202). Pengxiang Hu was further supported by the China Scholarship Council ([2013] 3009). David Heslop and Andrew Roberts were supported by Australian Research Council Discovery Project DP110105419

    Magnetism of Al-substituted magnetite reduced from Al-hematite

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    Aluminum-substituted magnetite (Al-magnetite) reduced from Al-substituted hematite or goethite (Al-hematite or Al-goethite) is an environmentally important constituent of magnetically enhanced soils. In order to characterize the magnetic properties of Al-magnetite, two series of Al-magnetite samples were synthesized through reduction of Al-hematite by a mixed gas (80% CO₂ and 20% CO) at 395°C for 72 h in a quartz tube furnace. Al-magnetite samples inherited the morphology of their parent Al-hematite samples, but only those transformed from Al-hematite synthesized at low temperature possessed surficial micropores, which originated from the release of structural water during heating. Surface micropores could thus serve as a practical fingerprint of fire or other high-temperature mineralogical alteration processes in natural environments, e.g., shear friction in seismic zones. In addition, Al substitution greatly affects the magnetic properties of Al-magnetite. For example, coercivity (Bc) increases with increasing Al content and then decreases slightly, while the saturation magnetization (Ms), Curie temperature (Tc), and Verwey transition temperature (Tv) all decrease with increasing Al content due to crystal defect formation and dilution of magnetic ions caused by Al incorporation. Moreover, different trends in the correlation between Tc and Bc can be used to discriminate titanomagnetite from Al-magnetite, which is likely to be important in environmental and paleomagnetic studies, particularly in soil.This study was supported by National Program on Global Change and Air-Sea Interaction (GASI-04-01-02), the National Natural Science Foundation of China (grants 41504055, 41430962, 41374073, and 41025013), and Chinese Continental Shelf Deep Drilling Program (GZH201100202). Z.X.J. further acknowledges support from the China Postdoctoral Science Foundation. A.P.R. and D.H. acknowledge support from the Australian Research Council (grants DP110105419 and DP120103952)
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