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Now showing 1 - 5 of 5
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    Ionophobicity of carbon sub-nanometer pores enables efficient desalination at high salinity
    (Maryland Heights, MO : Cell Press, 2022) Zhang, Yuan; Prehal, Christian; Jiang, Huili; Liu, Yang; Feng, Guang; Presser, Volker
    Electrochemical seawater desalination has drawn significant attention as an energy-efficient technique to address the global issue of water remediation. Microporous carbons, that is, carbons with pore sizes smaller than 2 nm, are commonly used for capacitive deionization. However, micropores are ineffective for capacitive deionization at high molar strength because of their inability to permselectively uptake ions. In our work, we combine experimental work with molecular dynamics simulation and reveal the ability of sub-nanometer pores (ultramicropores) to effectively desalinate aqueous media at seawater-like molar strength. This is done without any ion-exchange membrane. The desalination capacity in 600 mM reaches 12 mg/g, with a charge efficiency of 94% and high cycling stability over 200 cycles (97% of charge efficiency retention). Using molecular dynamic simulations and providing experimental data, our work makes it possible both to understand and to calculate desalination capacity and charge efficiency at high molar strength as a function of pore size.
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    Temperature-dependent dynamic compressive properties and failure mechanisms of the additively manufactured CoCrFeMnNi high entropy alloy
    (Oxford : Elsevier Science, 2022) Chen, Hongyu; Liu, Yang; Wang, Yonggang; Li, Zhiguo; Wang, Di; Kosiba, Konrad
    CoCrFeMnNi high entropy alloy (HEA) parts were fabricated by laser powder bed fusion (LPBF), and their dynamic compressive properties at different temperatures as well as the resulting microstructures were analyzed. The HEAs showed an unprecedented strength-ductility combination, especially at a cryogenic temperature of 77 K and a high strain rate of 3000 s−1. Under this testing condition, the yield strength (YS) of the HEAs amounted to 665 MPa. Regardless of the testing temperature, the deformation mechanism of all investigated HEAs was dominated by a synergistic effect consisting of deformation twinning and dislocation pile-up around twins. The fraction of twin boundaries and dislocation density within the deformed microstructure of the HEA correlated with the test temperature. At 77 K, the formation of nanotwins together with dislocation slip prevailed and contributed to pronounced twin-twin and twin-dislocation interactions which effectively restricted the dislocation movement and, hence, contributed to a higher YS as well as strain hardening rate in comparison to that of the HEAs at room temperature of 298 K. The LPBF-fabricated HEAs showed unpronounced thermal softening even at a high testing temperature of 1073 K. Continuous dynamic recrystallization was restricted in the HEA because of its inherent sluggish dislocation kinetics and low stacking fault energy.
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    Laser powder bed fusion of Fe60(CoCrNiMn)40 medium-entropy alloy with excellent strength-ductility balance
    (Amsterdam [u.a.] : Elsevier Science, 2024) Yang, Shengze; Liu, Yang; Chen, Hongyu; Wang, Yonggang; Kosiba, Konrad
    In this study, Fe60(CoCrNiMn)40 medium-entropy alloy (MEA) was fabricated by laser powder bed fusion (LPBF) via mixing of pure Fe and FeCoCrNiMn powders, the processability, microstructure and mechanical properties were systematically investigated, and the mechanism of strengthening and toughening were revealed through combination of experiments and molecular dynamics (MD) simulations. Results show that fraction of BCC phase decreased gradually with increasing volume energy density (VED), and thus heterostructue with varying FCC and BCC phases were produced through regulating the VED. The Fe60(CoCrNiMn)40 MEA (with scanning speeds of 700 and 800 mm/s) showed excellent strength-plasticity balance (e.g. 476 MPa, 612 MPa and 63 %) compared to the equiatomic FeCoCrNiMn HEA, which is ascribed to the synergistic strengthening and toughening effects involving the twinning induced plasticity (TWIP) and the reinforcement caused by the BCC phase (act as reinforced particle) embedded in the FCC matrix.
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    Laser additive manufacturing of Miura-origami tube inspired quasi-zero stiffness metamaterial with prominent longitudinal wave propagation
    (London [u.a.] : Taylor and Francis, 2023) Wan, Haoran; Chen, Hongyu; Wang, Yonggang; Fang, Xiang; Liu, Yang; Kosiba, Konrad
    Origami metamaterials have become frontiers of research in many disciplines due to their infinite design space, simple size variation, and topologically variable properties. In this study, a novel metamaterial inspired by Miura-origami tubes with a complex quasi-zero-stiffness (QZS) structure was fabricated via laser powder bed fusion (LPBF). The unit of the QZS metamaterial consists of a two-layer quadrilateral frame and two vertical springs attached to its diagonal points. The geometric accuracy, densification level and mechanical properties of the QZS parts fabricated at various processing conditions were investigated and the optimised processing parameters were determined. The displacement response of the QZS parts was analysed by experiments in conjunction with simulation analysis. The results show that the LPBF-fabricated QZS metamaterials form four extra-wide longitudinal wave band gaps under low frequencies from 660 Hz to 2500 Hz. The proposed LPBF-fabricated QZS metamaterial shows great potential in impeding the longitudinal vibration of engineering structures.
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    Accurate in vivo tumor detection using plasmonic-enhanced shifted-excitation Raman difference spectroscopy (SERDS)
    (Wyoming, NSW : Ivyspring, 2021) Strobbia, Pietro; Cupil-Garcia, Vanessa; Crawford, Bridget M.; Fales, Andrew M.; Pfefer, T. Joshua; Liu, Yang; Maiwald, Martin; Sumpf, Bernd; Vo-Dinh, Tuan
    For the majority of cancer patients, surgery is the primary method of treatment. In these cases, accurately removing the entire tumor without harming surrounding tissue is critical; however, due to the lack of intraoperative imaging techniques, surgeons rely on visual and physical inspection to identify tumors. Surface-enhanced Raman scattering (SERS) is emerging as a non-invasive optical alternative for intraoperative tumor identification, with high accuracy and stability. However, Raman detection requires dark rooms to work, which is not consistent with surgical settings. Methods: Herein, we used SERS nanoprobes combined with shifted-excitation Raman difference spectroscopy (SERDS) detection, to accurately detect tumors in xenograft murine model. Results: We demonstrate for the first time the use of SERDS for in vivo tumor detection in a murine model under ambient light conditions. We compare traditional Raman detection with SERDS, showing that our method can improve sensitivity and accuracy for this task. Conclusion: Our results show that this method can be used to improve the accuracy and robustness of in vivo Raman/SERS biomedical application, aiding the process of clinical translation of these technologies. © The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See http://ivyspring.com/terms for full terms and conditions.