Employing the spin-wave formalism within and beyond the harmonic-oscillator approx-imation, we study the dynamic structure factors of spin-12 nearest-neighbor quantum Heisenberg antiferromagnets on two-dimensional quasiperiodic lattices with particular emphasis on a mag-netic analog to the well-known confined states of a hopping Hamiltonian for independent electrons on a two-dimensional Penrose lattice. We present comprehensive calculations on the C5v Penrose tiling in comparison with the C8v Ammann–Beenker tiling, revealing their decagonal and octagonal antiferromagnetic microstructures. Their dynamic spin structure factors both exhibit linear soft modes emergent at magnetic Bragg wavevectors and have nearly or fairly flat scattering bands, signifying magnetic excitations localized in some way, at several different energies in a self-similar manner. In particular, the lowest-lying highly flat mode is distinctive of the Penrose lattice, which is mediated by its unique antiferromagnons confined within tricoordinated sites only, unlike their itinerant electron counterparts involving pentacoordinated, as well as tricoordinated, sites. Bringing harmonic antiferromagnons into higher-order quantum interaction splits, the lowest-lying nearly flat scattering band in two, each mediated by further confined antiferromagnons, which is fully demonstrated and throughly visualized in the perpendicular as well as real spaces. We disclose superconfined antiferromagnons on the two-dimensional Penrose lattice.
{"title":"Magnon Confinement on the Two-Dimensional Penrose Lattice: Perpendicular-Space Analysis of the Dynamic Structure Factor","authors":"Shoji Yamamoto, Takashi Inoue","doi":"10.3390/cryst14080702","DOIUrl":"https://doi.org/10.3390/cryst14080702","url":null,"abstract":"Employing the spin-wave formalism within and beyond the harmonic-oscillator approx-imation, we study the dynamic structure factors of spin-12 nearest-neighbor quantum Heisenberg antiferromagnets on two-dimensional quasiperiodic lattices with particular emphasis on a mag-netic analog to the well-known confined states of a hopping Hamiltonian for independent electrons on a two-dimensional Penrose lattice. We present comprehensive calculations on the C5v Penrose tiling in comparison with the C8v Ammann–Beenker tiling, revealing their decagonal and octagonal antiferromagnetic microstructures. Their dynamic spin structure factors both exhibit linear soft modes emergent at magnetic Bragg wavevectors and have nearly or fairly flat scattering bands, signifying magnetic excitations localized in some way, at several different energies in a self-similar manner. In particular, the lowest-lying highly flat mode is distinctive of the Penrose lattice, which is mediated by its unique antiferromagnons confined within tricoordinated sites only, unlike their itinerant electron counterparts involving pentacoordinated, as well as tricoordinated, sites. Bringing harmonic antiferromagnons into higher-order quantum interaction splits, the lowest-lying nearly flat scattering band in two, each mediated by further confined antiferromagnons, which is fully demonstrated and throughly visualized in the perpendicular as well as real spaces. We disclose superconfined antiferromagnons on the two-dimensional Penrose lattice.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"1 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vijayakumar Manavalan, Brad Coward, Vesna Najdanovic-Visak, Stephen D. Worrall
Supercapacitors hold promise for energy storage due to their exceptional power density and fast charge/discharge cycles. However, their performance hinges on the electrode material. Zeolitic imidazolate frameworks (ZIFs) are attractive options due to their tailorable structure and high surface area. But traditional ZIF synthesis relies on toxic solvents derived from fossil fuels, hindering their envisioned environmental benefit. This study explores using bio-derived solvents for a greener and potentially superior approach. The researchers employed anodic electrodeposition to synthesise cobalt-based ZIFs (Co-ZIFs) as supercapacitor electrode materials. Two linkers (2-methylimidazole and benzimidazole) and two bio-derived solvents (CyreneTM and γ-valerolactone (GVL)) were investigated. X-ray diffraction analysis revealed that bio-derived solvents enhanced the crystallinity of Co-ZIFs compared to traditional solvents. Notably, CyreneTM promoted better crystallinity for Co-bIM/Co-mIM structures. The Full Width at Half Maximum (FWHM) analysis suggests CyreneTM promotes Co-bIM/Co-mIM crystallinity (lower FWHM). Co-mIM in CyreneTM exhibits the best crystallinity (FWHM = 0.233) compared to other ZIF samples. Scanning electron microscopy confirmed these findings, showing larger and well-defined crystals for bio-derived solvent-synthesised ZIFs. The choice of solvent significantly impacted the final ZIF structure. While 2-methylimidazole consistently formed ZIF-67 regardless of the solvent, benzimidazole exhibited solvent-dependent behaviour. GVL yielded the highly porous Co-ZIF-12 structure, whereas DMF (N,N-dimethylformamide) and CyreneTM produced the less porous ZIF-9. This work reports the first-ever instance of ZIF-12 synthesis via an electrochemical method, highlighting the crucial interplay between solvent and precursor molecule in determining the final ZIF product. The synthesised binder-free Co-ZIF electrodes were evaluated for supercapacitor performance. The capacitance data revealed GVL as the most effective solvent, followed by DMF and then CyreneTM. This suggests GVL is the preferred choice for this reaction due to its superior performance. The ZIF-12-based electrode exhibits an impressive specific capacitance (Csp) of 44 F g⁻1, significantly higher than those achieved by ZIF-9-Cyrene (1.2 F g⁻1), ZIF-9-DMF (2.5 F g⁻1), ZIF-67-GVL (35 F g⁻1), ZIF-67-Cyrene (6 F g⁻1), and ZIF-67-DMF (16 F g⁻1) at 1 A g−1. This surpasses the Csp of all other ZIFs studied, including high-performing ZIF-67(GVL). ZIF-12(GVL) maintained superior Csp even at higher current densities, demonstrating exceptional rate capability. Among the bio-derived solvents, GVL outperformed CyreneTM. Notably, the Co-bIM in the GVL sample exhibited a ZIF-12-like structure, offering potential advantages due to its larger pores and potentially higher surface area compared to traditional ZIF-67 and ZIF-9 structures. This work presents a significant advancement in Co-ZIF synthesis. By uti
超级电容器因其超高的功率密度和快速充放电循环而在能量存储方面大有可为。然而，其性能取决于电极材料。沸石咪唑啉框架（ZIF）因其可定制的结构和高表面积而成为极具吸引力的选择。但传统的 ZIF 合成依赖于从化石燃料中提取的有毒溶剂，阻碍了其预期的环境效益。本研究探讨了使用生物衍生溶剂的更环保、更优越的方法。研究人员采用阳极电沉积法合成了钴基 ZIF（Co-ZIF）作为超级电容器电极材料。研究人员对两种连接剂（2-甲基咪唑和苯并咪唑）和两种生物衍生溶剂（CyreneTM 和 γ-戊内酯 (GVL)）进行了研究。X 射线衍射分析表明，与传统溶剂相比，生物衍生溶剂提高了 Co-ZIF 的结晶度。值得注意的是，CyreneTM 提高了 Co-bIM/Co-mIM 结构的结晶度。半最大值全宽（FWHM）分析表明，CyreneTM 提高了 Co-bIM/Co-mIM 的结晶度（FWHM 较低）。与其他 ZIF 样品相比，CyreneTM 中的 Co-mIM 结晶性最好（FWHM = 0.233）。扫描电子显微镜证实了这些发现，显示生物衍生溶剂合成的 ZIF 晶体更大、更清晰。溶剂的选择对最终的 ZIF 结构有很大影响。无论使用何种溶剂，2-甲基咪唑都能形成 ZIF-67，而苯并咪唑则表现出溶剂依赖性。GVL 产生了高孔隙率的 Co-ZIF-12 结构，而 DMF（N,N-二甲基甲酰胺）和 CyreneTM 则产生了孔隙率较低的 ZIF-9。这项工作首次报道了通过电化学方法合成 ZIF-12 的实例，强调了溶剂和前驱体分子之间在决定最终 ZIF 产品方面的重要相互作用。对合成的无粘合剂 Co-ZIF 电极进行了超级电容器性能评估。电容数据显示，GVL 是最有效的溶剂，其次是 DMF，然后是 CyreneTM。这表明 GVL 因其卓越的性能而成为该反应的首选。基于 ZIF-12 的电极显示出 44 F g-1 的惊人比电容 (Csp)，明显高于 ZIF-9-Cyrene (1.2 F g-1)、ZIF-9-DMF (2.5 F g-1)、ZIF-67-GVL (35 F g-1)、ZIF-67-Cyrene (6 F g-1) 和 ZIF-67-DMF (16 F g-1) 在 1 A g-1 下的比电容。这超过了所研究的所有其他 ZIF 的 Csp，包括高性能的 ZIF-67(GVL)。即使在更高的电流密度下，ZIF-12(GVL) 也能保持出色的 Csp，显示出卓越的速率能力。在生物衍生溶剂中，GVL 的性能优于 CyreneTM。值得注意的是，GVL 样品中的 Co-bIM 显示出类似 ZIF-12 的结构，与传统的 ZIF-67 和 ZIF-9 结构相比，它具有更大的孔隙和潜在的更高表面积，因而具有潜在的优势。这项工作是 Co-ZIF 合成技术的一大进步。通过利用生物衍生溶剂，它提供了一种更具可持续性和潜在优势的替代方法。这为以生态友好的方式生产出性能更好的 Co-ZIF，用于超级电容器、气体分离、催化和其他应用铺平了道路。
{"title":"Electrosynthesis of Co-ZIF Using Bio-Derived Solvents: Electrochemical Evaluation of Synthesised MOFs as a Binder-Free Supercapacitor Electrode in Alkaline Electrolyte","authors":"Vijayakumar Manavalan, Brad Coward, Vesna Najdanovic-Visak, Stephen D. Worrall","doi":"10.3390/cryst14080700","DOIUrl":"https://doi.org/10.3390/cryst14080700","url":null,"abstract":"Supercapacitors hold promise for energy storage due to their exceptional power density and fast charge/discharge cycles. However, their performance hinges on the electrode material. Zeolitic imidazolate frameworks (ZIFs) are attractive options due to their tailorable structure and high surface area. But traditional ZIF synthesis relies on toxic solvents derived from fossil fuels, hindering their envisioned environmental benefit. This study explores using bio-derived solvents for a greener and potentially superior approach. The researchers employed anodic electrodeposition to synthesise cobalt-based ZIFs (Co-ZIFs) as supercapacitor electrode materials. Two linkers (2-methylimidazole and benzimidazole) and two bio-derived solvents (CyreneTM and γ-valerolactone (GVL)) were investigated. X-ray diffraction analysis revealed that bio-derived solvents enhanced the crystallinity of Co-ZIFs compared to traditional solvents. Notably, CyreneTM promoted better crystallinity for Co-bIM/Co-mIM structures. The Full Width at Half Maximum (FWHM) analysis suggests CyreneTM promotes Co-bIM/Co-mIM crystallinity (lower FWHM). Co-mIM in CyreneTM exhibits the best crystallinity (FWHM = 0.233) compared to other ZIF samples. Scanning electron microscopy confirmed these findings, showing larger and well-defined crystals for bio-derived solvent-synthesised ZIFs. The choice of solvent significantly impacted the final ZIF structure. While 2-methylimidazole consistently formed ZIF-67 regardless of the solvent, benzimidazole exhibited solvent-dependent behaviour. GVL yielded the highly porous Co-ZIF-12 structure, whereas DMF (N,N-dimethylformamide) and CyreneTM produced the less porous ZIF-9. This work reports the first-ever instance of ZIF-12 synthesis via an electrochemical method, highlighting the crucial interplay between solvent and precursor molecule in determining the final ZIF product. The synthesised binder-free Co-ZIF electrodes were evaluated for supercapacitor performance. The capacitance data revealed GVL as the most effective solvent, followed by DMF and then CyreneTM. This suggests GVL is the preferred choice for this reaction due to its superior performance. The ZIF-12-based electrode exhibits an impressive specific capacitance (Csp) of 44 F g⁻1, significantly higher than those achieved by ZIF-9-Cyrene (1.2 F g⁻1), ZIF-9-DMF (2.5 F g⁻1), ZIF-67-GVL (35 F g⁻1), ZIF-67-Cyrene (6 F g⁻1), and ZIF-67-DMF (16 F g⁻1) at 1 A g−1. This surpasses the Csp of all other ZIFs studied, including high-performing ZIF-67(GVL). ZIF-12(GVL) maintained superior Csp even at higher current densities, demonstrating exceptional rate capability. Among the bio-derived solvents, GVL outperformed CyreneTM. Notably, the Co-bIM in the GVL sample exhibited a ZIF-12-like structure, offering potential advantages due to its larger pores and potentially higher surface area compared to traditional ZIF-67 and ZIF-9 structures. This work presents a significant advancement in Co-ZIF synthesis. By uti","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"8 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sonia J. Bailón-Ruiz, Yarilyn Cedeño-Mattei, Angelie M. Núñez-Colón, Kerianys Torres-Torres
Semiconductor Zn-based nanomaterials have emerged as promising agents for the photocatalytic degradation of organic pollutants in wastewater treatment. However, achieving efficient synthesis protocols capable of rapidly producing small structures directly in aqueous environments remains challenging. Microwave-assisted synthesis presents a viable solution by enabling one-step particle generation swiftly and directly in water through increased pressure, thereby easily elevating the boiling point. This study investigates the microwave-assisted one-step synthesis of pure and iron-doped ZnS nanoparticles and assesses their efficacy in photodegrading Quinoline Yellow (QY) in aqueous suspensions. The results demonstrate a significant degradation of QY in the presence of 1% iron-doped ZnS nanoparticles, achieving approximately 66.3% degradation with 500 ppm of doped nanoparticles after 270 min. These findings highlight the considerable potential of 1% iron-doped ZnS nanoparticles as effective nanocatalysts.
{"title":"Fast One-Step Microwave-Assisted Synthesis of Iron-Doped ZnS for Photocatalytic Applications","authors":"Sonia J. Bailón-Ruiz, Yarilyn Cedeño-Mattei, Angelie M. Núñez-Colón, Kerianys Torres-Torres","doi":"10.3390/cryst14080699","DOIUrl":"https://doi.org/10.3390/cryst14080699","url":null,"abstract":"Semiconductor Zn-based nanomaterials have emerged as promising agents for the photocatalytic degradation of organic pollutants in wastewater treatment. However, achieving efficient synthesis protocols capable of rapidly producing small structures directly in aqueous environments remains challenging. Microwave-assisted synthesis presents a viable solution by enabling one-step particle generation swiftly and directly in water through increased pressure, thereby easily elevating the boiling point. This study investigates the microwave-assisted one-step synthesis of pure and iron-doped ZnS nanoparticles and assesses their efficacy in photodegrading Quinoline Yellow (QY) in aqueous suspensions. The results demonstrate a significant degradation of QY in the presence of 1% iron-doped ZnS nanoparticles, achieving approximately 66.3% degradation with 500 ppm of doped nanoparticles after 270 min. These findings highlight the considerable potential of 1% iron-doped ZnS nanoparticles as effective nanocatalysts.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"108 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phononic crystals (PnCs) have garnered significant attention due to their unique ability to control elastic waves in unconventional ways. One area of research focuses on utilizing defects within PnCs. Defects create new pass bands within band gaps, leading to concentrated wave energy within the defects. However, defect-mode-enabled wave localization is effective only at specific frequencies, limiting its usefulness when the frequencies of incident waves vary. Existing methods to mechanically tune defect bands involve changing the geometries of unit cells or defects or attaching elastic foundations, which necessitates the detachment and reattachment of certain structures depending on the engineering situation. Considering these challenges, this study introduces a novel approach that utilizes the reconfigurable PnC design, incorporating permanent magnets and ferromagnetic materials. The case study involves a one-dimensional PnC consisting of a long metal beam with rectangular block-shaped permanent magnets periodically arranged and attached to the beam by magnetic forces. A defect is created by shifting a subset of these block-shaped permanent magnets in parallel. The extent of this parallel movement alters the vibrating characteristics of the defect, facilitating the mechanical control of the defect bands in the defective PnC. The effectiveness of this approach is experimentally validated.
{"title":"Experimental Validation for Mechanically Tunable Defect Bands of a Reconfigurable Phononic Crystal with Permanent Magnets","authors":"Jeonggyu Yang, Soo-Ho Jo","doi":"10.3390/cryst14080701","DOIUrl":"https://doi.org/10.3390/cryst14080701","url":null,"abstract":"Phononic crystals (PnCs) have garnered significant attention due to their unique ability to control elastic waves in unconventional ways. One area of research focuses on utilizing defects within PnCs. Defects create new pass bands within band gaps, leading to concentrated wave energy within the defects. However, defect-mode-enabled wave localization is effective only at specific frequencies, limiting its usefulness when the frequencies of incident waves vary. Existing methods to mechanically tune defect bands involve changing the geometries of unit cells or defects or attaching elastic foundations, which necessitates the detachment and reattachment of certain structures depending on the engineering situation. Considering these challenges, this study introduces a novel approach that utilizes the reconfigurable PnC design, incorporating permanent magnets and ferromagnetic materials. The case study involves a one-dimensional PnC consisting of a long metal beam with rectangular block-shaped permanent magnets periodically arranged and attached to the beam by magnetic forces. A defect is created by shifting a subset of these block-shaped permanent magnets in parallel. The extent of this parallel movement alters the vibrating characteristics of the defect, facilitating the mechanical control of the defect bands in the defective PnC. The effectiveness of this approach is experimentally validated.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"54 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the radiative relaxation of electronic excitations through luminescence spectroscopy techniques applied to high-purity KBr crystals subjected to low-temperature (85 K) uniaxial deformation along the <100> and <110> crystallographic directions. Results demonstrate that the most significant enhancement in the intensity of σ-(4.42 eV) and π-(2.3 eV) luminescence from self-trapped excitons in KBr crystals occurs with elastic deformation along the <110> direction, aligning with the axis of the hole component of the anion self-trapped exciton. Deformation-induced changes in X-ray, tunneling, and thermally stimulated luminescence spectra reveal a new band, denoted as Ex, peaking at approximately 3.58 eV, attributed to tunneling charge exchange between the F’- and VK-centers in their ground state.
{"title":"Mechanisms for Enhancing Luminescence Yield in KBr Crystals under the Influence of Low-Temperature Uniaxial Elastic Deformation","authors":"Kuanyshbek Shunkeyev, Shynar Sagimbayeva, Zhiger Ubaev, Adelya Kenzhebayeva","doi":"10.3390/cryst14080698","DOIUrl":"https://doi.org/10.3390/cryst14080698","url":null,"abstract":"This study investigates the radiative relaxation of electronic excitations through luminescence spectroscopy techniques applied to high-purity KBr crystals subjected to low-temperature (85 K) uniaxial deformation along the <100> and <110> crystallographic directions. Results demonstrate that the most significant enhancement in the intensity of σ-(4.42 eV) and π-(2.3 eV) luminescence from self-trapped excitons in KBr crystals occurs with elastic deformation along the <110> direction, aligning with the axis of the hole component of the anion self-trapped exciton. Deformation-induced changes in X-ray, tunneling, and thermally stimulated luminescence spectra reveal a new band, denoted as Ex, peaking at approximately 3.58 eV, attributed to tunneling charge exchange between the F’- and VK-centers in their ground state.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"31 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiao Wang, Zizhi Ying, En Hu, Juntao Ma, Xiaoqing Zhang, Tengfei Ma, Xiaohong Wang
To refine the grain size and improve the mechanical properties of ultrahigh-strength aluminum alloy (Al-10Zn-1.9Mg-1.6Cu-0.12Zr), the Al-Ti-B-Er grain refiner was prepared by the melt reaction method using the aluminum melt and Al + Ti + B precursor. The results exhibit that the Al-Ti-B-Er grain refiner is mainly composed of a block TiAl3 phase, and loose agglomerated nano-sized TiB2 and Al3Er phases. The microstructure of ultrahigh-strength aluminum is significantly affected by the Al-Ti-B-Er refiner, which changes from dendrite to equiaxial grain with increasing Al-Ti-B-Er content, and the size of the eutectic phase is significantly refined. The high-efficiency refinement of Al-Ti-B-Er is due to Er promoting the uniform distribution of TiAl3 particles and the formation of loose agglomerated nano-sized TiB2 particles. The optimal addition content of Al-Ti-B-Er into ultrahigh-strength aluminum alloys is 1 wt%, whose grain size is approximately 40 µm. Additionally, the strength and ductility of ultrahigh-strength aluminum alloys are simultaneously improved by adding 1wt% Al-Ti-B-Er after the T6 treatment, reaching 756 MPa and 20%, respectively. This enhancement in strength and ductility is mainly attributed to grain refinement and the eutectic phase refinement.
为了细化超高强度铝合金（Al-10Zn-1.9Mg-1.6Cu-0.12Zr）的晶粒尺寸并改善其机械性能，研究人员利用铝熔体和 Al + Ti + B 前驱体，采用熔融反应法制备了 Al-Ti-B-Er 晶粒细化剂。结果表明，Al-Ti-B-Er 晶粒细化剂主要由块状 TiAl3 相、疏松团聚的纳米级 TiB2 相和 Al3Er 相组成。Al-Ti-B-Er 精炼剂对超高强度铝的微观结构影响显著，随着 Al-Ti-B-Er 含量的增加，铝的微观结构由树枝状晶粒转变为等轴晶粒，共晶相的尺寸也显著细化。Al-Ti-B-Er 的高效细化是由于 Er 促进了 TiAl3 颗粒的均匀分布和疏松团聚纳米级 TiB2 颗粒的形成。超高强度铝合金中 Al-Ti-B-Er 的最佳添加量为 1 wt%，其晶粒大小约为 40 µm。此外，在 T6 处理后添加 1wt% 的 Al-Ti-B-Er，可同时提高超高强度铝合金的强度和延展性，分别达到 756 兆帕和 20%。强度和延展性的提高主要归因于晶粒细化和共晶相细化。
{"title":"Effect of Al-Ti-B-Er on the Microstructure and Properties of Ultrahigh-Strength Aluminum Alloy","authors":"Xiao Wang, Zizhi Ying, En Hu, Juntao Ma, Xiaoqing Zhang, Tengfei Ma, Xiaohong Wang","doi":"10.3390/cryst14080695","DOIUrl":"https://doi.org/10.3390/cryst14080695","url":null,"abstract":"To refine the grain size and improve the mechanical properties of ultrahigh-strength aluminum alloy (Al-10Zn-1.9Mg-1.6Cu-0.12Zr), the Al-Ti-B-Er grain refiner was prepared by the melt reaction method using the aluminum melt and Al + Ti + B precursor. The results exhibit that the Al-Ti-B-Er grain refiner is mainly composed of a block TiAl3 phase, and loose agglomerated nano-sized TiB2 and Al3Er phases. The microstructure of ultrahigh-strength aluminum is significantly affected by the Al-Ti-B-Er refiner, which changes from dendrite to equiaxial grain with increasing Al-Ti-B-Er content, and the size of the eutectic phase is significantly refined. The high-efficiency refinement of Al-Ti-B-Er is due to Er promoting the uniform distribution of TiAl3 particles and the formation of loose agglomerated nano-sized TiB2 particles. The optimal addition content of Al-Ti-B-Er into ultrahigh-strength aluminum alloys is 1 wt%, whose grain size is approximately 40 µm. Additionally, the strength and ductility of ultrahigh-strength aluminum alloys are simultaneously improved by adding 1wt% Al-Ti-B-Er after the T6 treatment, reaching 756 MPa and 20%, respectively. This enhancement in strength and ductility is mainly attributed to grain refinement and the eutectic phase refinement.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"123 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oliver Daniel Schreiner, Petrisor Samoila, Thomas Gabriel Schreiner, Diana Socotar, Romeo Cristian Ciobanu
This paper describes a process to obtain magnetite functionalized with carboxymethylcellulose via coprecipitation by means of a preliminary stabilization of magnetite in citric acid. The magnetite assemblies successfully passed in vitro and in vivo tests of bio-compatibility. The measured values for the dielectric loss factor are remarkably high, a prerequisite for the assemblies’ potential use as contrast agents. Broadband THz spectroscopy analysis was performed to identify the most relevant frequency bands (here, 3.2–4 THz) where the signal difference between normal cells and cancer cells is relevant for the particles’ potential use as contrast agents for THz imaging, with applications in oncology.
{"title":"Synthesis and Characterization of Carboxymethylcellulose-Functionalized Magnetite Nanoparticles as Contrast Agents for THz Spectroscopy with Applications in Oncology","authors":"Oliver Daniel Schreiner, Petrisor Samoila, Thomas Gabriel Schreiner, Diana Socotar, Romeo Cristian Ciobanu","doi":"10.3390/cryst14080696","DOIUrl":"https://doi.org/10.3390/cryst14080696","url":null,"abstract":"This paper describes a process to obtain magnetite functionalized with carboxymethylcellulose via coprecipitation by means of a preliminary stabilization of magnetite in citric acid. The magnetite assemblies successfully passed in vitro and in vivo tests of bio-compatibility. The measured values for the dielectric loss factor are remarkably high, a prerequisite for the assemblies’ potential use as contrast agents. Broadband THz spectroscopy analysis was performed to identify the most relevant frequency bands (here, 3.2–4 THz) where the signal difference between normal cells and cancer cells is relevant for the particles’ potential use as contrast agents for THz imaging, with applications in oncology.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"214 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the strong reducibility and chemical activity of rare earths, the diffusion behavior and secondary oxidation of rare earths in the steel liquid will also have a significant impact on the modified products when rare earths are added to bearing steel, resulting in poor control of distribution behavior. Therefore, this paper studies the influence of time factors on the evolution of rare earth inclusions. The inclusion evolution behavior at different times when the bearing steel was treated with rare earths and subjected to secondary oxidation was simulated at 1873 K (1600 °C). At a cerium content of 0.012% in steel and a secondary oxidation of 0.0025%, the cerium content in steel and the total oxygen (T.O.) content in steel were determined at the 30 s, 3 min, 5 min, and 7 min after the addition and the inclusions were characterized by automatic scanning electron microscopy. The results demonstrated the formation of a cerium-enriched zone after the addition of the cerium alloy to the steel. As time progressed, a considerable number of inclusions were generated in the cerium-enriched zone, which subsequently disappeared. The trend in the composition of the inclusions can be described as Al2O3 → Ce2O2S + CeS → Ce2O2S. The final composition of the inclusions matches the thermodynamic phase diagram. Following the addition of the transient oxidant Fe2O3 to the molten steel, an oxygen-enriched zone was formed. As time progressed, a considerable number of inclusions were generated in the oxygen-enriched zone and subsequently disappeared. The trend of inclusions composition was as follows: Ce2O3 + CeAlO3 + Al2O3 → Ce2O3 + CeAlO3 → Ce2O2S + CeAlO3. The final inclusion composition coincides with the thermodynamic phase diagram.
{"title":"Time-Dependent Study of Inclusions in Bearing Steel Subjected to Rare Earth Treatment with Secondary Oxidation","authors":"Weining Wang, Wenzhi Xia, Yun Zhou, Aijun Deng, Guangda Bao, Zhiyou Liao, Haichuan Wang","doi":"10.3390/cryst14080697","DOIUrl":"https://doi.org/10.3390/cryst14080697","url":null,"abstract":"Due to the strong reducibility and chemical activity of rare earths, the diffusion behavior and secondary oxidation of rare earths in the steel liquid will also have a significant impact on the modified products when rare earths are added to bearing steel, resulting in poor control of distribution behavior. Therefore, this paper studies the influence of time factors on the evolution of rare earth inclusions. The inclusion evolution behavior at different times when the bearing steel was treated with rare earths and subjected to secondary oxidation was simulated at 1873 K (1600 °C). At a cerium content of 0.012% in steel and a secondary oxidation of 0.0025%, the cerium content in steel and the total oxygen (T.O.) content in steel were determined at the 30 s, 3 min, 5 min, and 7 min after the addition and the inclusions were characterized by automatic scanning electron microscopy. The results demonstrated the formation of a cerium-enriched zone after the addition of the cerium alloy to the steel. As time progressed, a considerable number of inclusions were generated in the cerium-enriched zone, which subsequently disappeared. The trend in the composition of the inclusions can be described as Al2O3 → Ce2O2S + CeS → Ce2O2S. The final composition of the inclusions matches the thermodynamic phase diagram. Following the addition of the transient oxidant Fe2O3 to the molten steel, an oxygen-enriched zone was formed. As time progressed, a considerable number of inclusions were generated in the oxygen-enriched zone and subsequently disappeared. The trend of inclusions composition was as follows: Ce2O3 + CeAlO3 + Al2O3 → Ce2O3 + CeAlO3 → Ce2O2S + CeAlO3. The final inclusion composition coincides with the thermodynamic phase diagram.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"49 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Uranium silicide (U3Si2) is regarded as a viable fuel option for improving the safety of nuclear power plants. In the present work, phase-field simulations were employed to investigate grain growth phenomena, encompassing both isotropic and anisotropic grain growth. In simulations of isotropic grain growth, it is commonly assumed that the energy and mobility of the grain boundaries (GBs) remain constant, represented by average values. The calculated grain growth kinetic rate constant, K, exhibits a close correspondence with the experimental measurements, indicating a strong agreement between the two. In simulations of anisotropic grain growth, the values of GB energy and mobility are correlated with the angular disparity between GBs. The simulation results demonstrated that the growth rate of U3Si2 can be influenced by both the energy anisotropy and mobility anisotropy of GBs. Furthermore, the anisotropy in mobility results in a greater prevalence of low-angle GB distribution in comparison to high-angle GBs. However, the energy anisotropy of GBs does not impact the frequency distribution of the angle difference between GBs.
{"title":"Phase-Field Simulation of Grain Growth in Uranium Silicide Nuclear Fuel","authors":"Xiaoqiang Pan, Yongxiao La, Yuxuan Liao, Yifan Wang, Yonghong Lu, Wenbo Liu","doi":"10.3390/cryst14080691","DOIUrl":"https://doi.org/10.3390/cryst14080691","url":null,"abstract":"Uranium silicide (U3Si2) is regarded as a viable fuel option for improving the safety of nuclear power plants. In the present work, phase-field simulations were employed to investigate grain growth phenomena, encompassing both isotropic and anisotropic grain growth. In simulations of isotropic grain growth, it is commonly assumed that the energy and mobility of the grain boundaries (GBs) remain constant, represented by average values. The calculated grain growth kinetic rate constant, K, exhibits a close correspondence with the experimental measurements, indicating a strong agreement between the two. In simulations of anisotropic grain growth, the values of GB energy and mobility are correlated with the angular disparity between GBs. The simulation results demonstrated that the growth rate of U3Si2 can be influenced by both the energy anisotropy and mobility anisotropy of GBs. Furthermore, the anisotropy in mobility results in a greater prevalence of low-angle GB distribution in comparison to high-angle GBs. However, the energy anisotropy of GBs does not impact the frequency distribution of the angle difference between GBs.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"153 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bo Cheng, Zengxuan Jiang, Yuxiao Zou, Guofeng Song
The angle of incidence of the compact polarization conversion device is crucial for practical use in integrated miniaturized optical systems. However, this index is often ignored in the design of quarter-wave plate based on metasurface. Herein, it is shown that a thick metallic cross-shaped hole array supports extraordinary optical transmission peaks controlled by a Fabry–Pérot (FP) resonator mode. The positions of these peaks have been proven to be independent over a large range of incidence angles. We numerically design a miniatured quarter-wave plate (QWP) with an 80 nm bandwidth (840~920 nm) and approximately 80% average efficiency capable of effectively functioning as a linear-to-circular (LTC) polarization converter at an incidence inclination angle of less than 30°. This angle-insensitive compact polarization conversion device may be significant in a new generation of integrated metasurface-based photonics devices.
{"title":"A Highly Efficient Plasmonic Polarization Conversion Metasurface Supporting a Large Angle of Incidence","authors":"Bo Cheng, Zengxuan Jiang, Yuxiao Zou, Guofeng Song","doi":"10.3390/cryst14080694","DOIUrl":"https://doi.org/10.3390/cryst14080694","url":null,"abstract":"The angle of incidence of the compact polarization conversion device is crucial for practical use in integrated miniaturized optical systems. However, this index is often ignored in the design of quarter-wave plate based on metasurface. Herein, it is shown that a thick metallic cross-shaped hole array supports extraordinary optical transmission peaks controlled by a Fabry–Pérot (FP) resonator mode. The positions of these peaks have been proven to be independent over a large range of incidence angles. We numerically design a miniatured quarter-wave plate (QWP) with an 80 nm bandwidth (840~920 nm) and approximately 80% average efficiency capable of effectively functioning as a linear-to-circular (LTC) polarization converter at an incidence inclination angle of less than 30°. This angle-insensitive compact polarization conversion device may be significant in a new generation of integrated metasurface-based photonics devices.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"78 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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