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}
Half-metallic semi-Heusler compounds (also known as half-Heusler compounds) are currently at the forefront of scientific research due to their potential applications in spintronic devices. Unlike other semi-Heuslers, the p0(d0)-d compounds do not appear to crystallize in the typical variant of the C1b structure. We investigate this phenomenon in the p0-d Heusler compounds LiYGa and LiYGe, where Y varies between Ca and Zn, using first-principles ab initio electronic band-structure calculations. We examine the electronic and magnetic properties of these compounds in relation to the three possible C1b structures. Notably, LiVGa, LiVGe, LiMnGa, and LiCrGe are half-metallic ferromagnets across all three variations of the C1b lattice structure. Our findings will serve as a foundation for future experimental studies on these compounds.
半金属半海斯勒化合物（又称半海斯勒化合物）因其在自旋电子器件中的潜在应用，目前正处于科学研究的前沿。与其他半海斯勒化合物不同，p0(d0)-d 化合物似乎不会以 C1b 结构的典型变体形式结晶。我们利用第一原理 ab initio 电子能带结构计算，研究了 p0-d Heusler 化合物 LiYGa 和 LiYGe（其中 Y 在 Ca 和 Zn 之间变化）中的这一现象。我们研究了这些化合物与三种可能的 C1b 结构相关的电子和磁性能。值得注意的是，在 C1b 晶格结构的所有三种变化中，LiVGa、LiVGe、LiMnGa 和 LiCrGe 都是半金属铁磁体。我们的发现将为今后对这些化合物的实验研究奠定基础。
{"title":"Interplay between Structural, Electronic, and Magnetic Properties in the p0-d Semi-Heusler Compounds: The Case of Li-Based Compounds","authors":"Kemal Özdoğan, Iosif Galanakis","doi":"10.3390/cryst14080693","DOIUrl":"https://doi.org/10.3390/cryst14080693","url":null,"abstract":"Half-metallic semi-Heusler compounds (also known as half-Heusler compounds) are currently at the forefront of scientific research due to their potential applications in spintronic devices. Unlike other semi-Heuslers, the p0(d0)-d compounds do not appear to crystallize in the typical variant of the C1b structure. We investigate this phenomenon in the p0-d Heusler compounds LiYGa and LiYGe, where Y varies between Ca and Zn, using first-principles ab initio electronic band-structure calculations. We examine the electronic and magnetic properties of these compounds in relation to the three possible C1b structures. Notably, LiVGa, LiVGe, LiMnGa, and LiCrGe are half-metallic ferromagnets across all three variations of the C1b lattice structure. Our findings will serve as a foundation for future experimental studies on these compounds.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"45 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871900","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}
Abdulla F. Alshater, Abbas S. Hakeem, Ablikim Bake, Hatim D. Mohamed, Hosni M. Ezuber, Alia Mustafa, Ruqayah R. Alnasser, Mezna K. Al Ruwaihi, Aysha I. Rashdan, Fatema A. Jaberi, Khadija S. Bahar
In a quest to vet UNS S32205 as a potential structural material to serve moderate-to-high temperature operations of NPP auxiliary components, the DL-EPR test was exploited. A bifronted scheme comprised of 650 and 850 °C discrete treatments intended to explore progressive eutectoid decomposition and degree-of-sensitization (DoS) scenarios was adopted. The nuance witnessed with yet another dual approach—the Cihal- and image processing (IP)-normalized signal landscape—was rationalized through its attribution to culprit microstructures. This was sought, inter alia, in the vicinity of grain boundaries and σ-phase inclusions by virtue of postmortem FESEM, STEM-EDX, HRTEM SAED and XRD ascertainment. Discernable reactivation-kinetics resurgence was believed to mark the onset of deleterious σ-phase dissolution. This only came into fruition with longer ageing times (8–17 h) at 650 °C and succumbed to prematurely (1 h), and at DC biases more cathodic than −0.25 VAg/AgCl with the 850 °C counterpart. Opportune corroboration was offered in ir/ia breakaway for the respective conditions, which was unveiled to be particularly pre-emptive (5 h) with IP- vs. Cihal-normalized peers (8 h) related to the 650 °C condition. Meanwhile, the 850 °C condition endured a similar surge after as little as 1 h of ageing across the board, which hints at concomitant sigma-phase culpability.
为了将 UNS S32205 作为一种潜在的结构材料，用于核电厂辅助部件的中高温运行，我们利用了 DL-EPR 试验。该试验采用了一个由 650 和 850 °C 离散处理组成的双轨方案，旨在探索渐进式共晶分解和敏化度 (DoS) 方案。通过另一种双重方法--Cihal 和图像处理 (IP) 归一化信号景观--所观察到的细微差别通过归因于罪魁祸首的微观结构得到了合理化。除其他外，还通过死后 FESEM、STEM-EDX、HRTEM SAED 和 XRD 确定了晶界和 σ 相夹杂物附近的情况。可辨别的再活化-动力学恢复被认为标志着有害σ相溶解的开始。这种情况只有在 650 °C 下经过较长的老化时间（8-17 小时）后才会出现，并在过早（1 小时）和直流偏压高于 -0.25 VAg/AgCl 的阴极时（与 850 °C 对应）才会消失。相应条件下的ir/ia断裂提供了适当的佐证，650 °C条件下的ir/ia断裂尤其先发制人（5小时），IP与Cihal归一化同行（8小时）。与此同时，850 °C条件在经过短短1小时的老化后也出现了类似的激增，这暗示了同时发生的西格玛阶段的罪魁祸首。
{"title":"A Bi-Pronged Attempt at Normalizing DL-EPRT Vis-à-Vis Grain-Boundary/σ-Phase Locales in Thermally Sensitized UNS S32205 Duplex Stainless Steel","authors":"Abdulla F. Alshater, Abbas S. Hakeem, Ablikim Bake, Hatim D. Mohamed, Hosni M. Ezuber, Alia Mustafa, Ruqayah R. Alnasser, Mezna K. Al Ruwaihi, Aysha I. Rashdan, Fatema A. Jaberi, Khadija S. Bahar","doi":"10.3390/cryst14080692","DOIUrl":"https://doi.org/10.3390/cryst14080692","url":null,"abstract":"In a quest to vet UNS S32205 as a potential structural material to serve moderate-to-high temperature operations of NPP auxiliary components, the DL-EPR test was exploited. A bifronted scheme comprised of 650 and 850 °C discrete treatments intended to explore progressive eutectoid decomposition and degree-of-sensitization (DoS) scenarios was adopted. The nuance witnessed with yet another dual approach—the Cihal- and image processing (IP)-normalized signal landscape—was rationalized through its attribution to culprit microstructures. This was sought, inter alia, in the vicinity of grain boundaries and σ-phase inclusions by virtue of postmortem FESEM, STEM-EDX, HRTEM SAED and XRD ascertainment. Discernable reactivation-kinetics resurgence was believed to mark the onset of deleterious σ-phase dissolution. This only came into fruition with longer ageing times (8–17 h) at 650 °C and succumbed to prematurely (1 h), and at DC biases more cathodic than −0.25 VAg/AgCl with the 850 °C counterpart. Opportune corroboration was offered in ir/ia breakaway for the respective conditions, which was unveiled to be particularly pre-emptive (5 h) with IP- vs. Cihal-normalized peers (8 h) related to the 650 °C condition. Meanwhile, the 850 °C condition endured a similar surge after as little as 1 h of ageing across the board, which hints at concomitant sigma-phase culpability.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"175 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141871901","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}
Kevon Kadiwala, Luize Dipane, Eriks Dipans, Arturs Bundulis, Martins Zubkins, Andrejs Ogurcovs, Jevgenijs Gabrusenoks, Dmitry Bocharov, Edgars Butanovs, Boris Polyakov
The promise of two-dimensional (2D) rhenium diselenide (ReSe2) in electronics and optoelectronics has sparked considerable interest in this material. However, achieving the growth of high-quality ReSe2 thin films on a wafer scale remains a significant challenge. In this study, we adopted a two-step method to produce ReSe2 thin films by combining magnetron sputtering of Re and ReOx onto flat substrates with subsequent selenization via atmospheric pressure chemical vapor transport (CVT). After analyzing the produced films using X-ray diffraction to identify the crystalline phase in formed thin film and scanning electron microscopy (SEM) to examine surface morphology, it was determined that the suitable temperature range for the 15 min selenization process with CVT is 650 °C–750 °C. Further investigation of these optimally produced ReSe2 thin films included atomic force microscopy (AFM), X-ray photoelectron spectroscopy, and Raman spectroscopy. The bulk electrical analysis of these films and AFM and SEM surface morphology revealed a strong reliance on the type of precursor material used for their synthesis, whereas optical measurements indicated a potential for the films in non-linear optics applications, irrespective of the precursor or temperature used. This study not only provides a new pathway for the growth of ReSe2 films but also sheds light on the synthesis approaches of other 2D transition metal dichalcogenide materials.
{"title":"Synthesis and Investigation of ReSe2 Thin Films Obtained from Magnetron Sputtered Re and ReOx","authors":"Kevon Kadiwala, Luize Dipane, Eriks Dipans, Arturs Bundulis, Martins Zubkins, Andrejs Ogurcovs, Jevgenijs Gabrusenoks, Dmitry Bocharov, Edgars Butanovs, Boris Polyakov","doi":"10.3390/cryst14080690","DOIUrl":"https://doi.org/10.3390/cryst14080690","url":null,"abstract":"The promise of two-dimensional (2D) rhenium diselenide (ReSe2) in electronics and optoelectronics has sparked considerable interest in this material. However, achieving the growth of high-quality ReSe2 thin films on a wafer scale remains a significant challenge. In this study, we adopted a two-step method to produce ReSe2 thin films by combining magnetron sputtering of Re and ReOx onto flat substrates with subsequent selenization via atmospheric pressure chemical vapor transport (CVT). After analyzing the produced films using X-ray diffraction to identify the crystalline phase in formed thin film and scanning electron microscopy (SEM) to examine surface morphology, it was determined that the suitable temperature range for the 15 min selenization process with CVT is 650 °C–750 °C. Further investigation of these optimally produced ReSe2 thin films included atomic force microscopy (AFM), X-ray photoelectron spectroscopy, and Raman spectroscopy. The bulk electrical analysis of these films and AFM and SEM surface morphology revealed a strong reliance on the type of precursor material used for their synthesis, whereas optical measurements indicated a potential for the films in non-linear optics applications, irrespective of the precursor or temperature used. This study not only provides a new pathway for the growth of ReSe2 films but also sheds light on the synthesis approaches of other 2D transition metal dichalcogenide materials.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"36 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141873227","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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