Franziska U. Huschmann, Janis Mueller, Alexander Metz, Moritz Ruf, Johanna Senst, Serghei Glinca, Johannes Schiebel, Andreas Heine, Gerhard Klebe
Fragment screening directly on protein crystals has been applied using AnalytiCon’s collection of intermediates that have been utilized to generate libraries of larger synthetic natural product-like molecules. The fragments with well-balanced physicochemical properties show an impressively high hit rate for a screen using the aspartic protease endothiapepsin. The subsequent validation and expansion of the discovered fragment hits benefits from AnalytiCon’s comprehensive library design. Since the screened fragments are intermediates that share a common core with larger and closely related analogs with modulated substitution patterns, they allow for the retrieval of off-the-shelf follow-up compounds, which enable the development of design strategies for fragment optimization. A promising bicyclic core scaffold found in several fragment hits could be validated by selecting a set of enlarged follow-up compounds. Due to unexpected changes in binding mode and no significant improvement in ligand efficiency, this series was quickly deemed unsuitable and therefore discontinued. The structures of follow-up compounds of two other fragments helped to evaluate a putative fusion of two overlapping fragment hits. A design concept on how to fuse the two fragments could be proposed and helps to plan a suitable substitution pattern and promising central bridging element.
{"title":"Screening, Growing, and Validation by Catalog: Using Synthetic Intermediates from Natural Product Libraries to Discover Fragments for an Aspartic Protease Through Crystallography","authors":"Franziska U. Huschmann, Janis Mueller, Alexander Metz, Moritz Ruf, Johanna Senst, Serghei Glinca, Johannes Schiebel, Andreas Heine, Gerhard Klebe","doi":"10.3390/cryst14090755","DOIUrl":"https://doi.org/10.3390/cryst14090755","url":null,"abstract":"Fragment screening directly on protein crystals has been applied using AnalytiCon’s collection of intermediates that have been utilized to generate libraries of larger synthetic natural product-like molecules. The fragments with well-balanced physicochemical properties show an impressively high hit rate for a screen using the aspartic protease endothiapepsin. The subsequent validation and expansion of the discovered fragment hits benefits from AnalytiCon’s comprehensive library design. Since the screened fragments are intermediates that share a common core with larger and closely related analogs with modulated substitution patterns, they allow for the retrieval of off-the-shelf follow-up compounds, which enable the development of design strategies for fragment optimization. A promising bicyclic core scaffold found in several fragment hits could be validated by selecting a set of enlarged follow-up compounds. Due to unexpected changes in binding mode and no significant improvement in ligand efficiency, this series was quickly deemed unsuitable and therefore discontinued. The structures of follow-up compounds of two other fragments helped to evaluate a putative fusion of two overlapping fragment hits. A design concept on how to fuse the two fragments could be proposed and helps to plan a suitable substitution pattern and promising central bridging element.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"28 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202545","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}
Qing Wan, Zeping Li, Huifeng Wang, Gang Xiong, Geng Wang
High-permittivity Ba(Eu1/5Sm1/5Nd1/5Pr1/5La1/5)2Ti4O12 (BESNPLT) high-entropy ceramics (HECs) were synthesized via a solid-state route. The microstructure, sintering behavior, phase structure, vibration modes, and microwave dielectric characteristics of the BESNPLT HECs were thoroughly investigated. The phase structure of the BESNPLT HECs was confirmed to be a single-phase orthorhombic tungsten-bronze-type structure of Pnma space group. Permittivity (εr) was primarily influenced by polarizability and relative density. The quality factor (Q×f) exhibited a significant correlation with packing fraction, whereas the temperature coefficient (TCF) of the BESNPLT HECs closely depended on the tolerance factor and bond valence of B-site. The BESNPLT HECs sintered at 1400 °C, demonstrating high relative density (>97%) and optimum microwave dielectric characteristics with TCF = +38.9 ppm/°C, Q×f = 8069 GHz (@6.1 GHz), and εr = 87.26. This study indicates that high-entropy strategy was an efficient route in modifying the dielectric characteristics of tungsten-bronze-type microwave ceramics.
{"title":"Crystal Structure and Microwave Dielectric Characteristics of Novel Ba(Eu1/5Sm1/5Nd1/5Pr1/5La1/5)2Ti4O12 High-Entropy Ceramic","authors":"Qing Wan, Zeping Li, Huifeng Wang, Gang Xiong, Geng Wang","doi":"10.3390/cryst14090754","DOIUrl":"https://doi.org/10.3390/cryst14090754","url":null,"abstract":"High-permittivity Ba(Eu1/5Sm1/5Nd1/5Pr1/5La1/5)2Ti4O12 (BESNPLT) high-entropy ceramics (HECs) were synthesized via a solid-state route. The microstructure, sintering behavior, phase structure, vibration modes, and microwave dielectric characteristics of the BESNPLT HECs were thoroughly investigated. The phase structure of the BESNPLT HECs was confirmed to be a single-phase orthorhombic tungsten-bronze-type structure of Pnma space group. Permittivity (εr) was primarily influenced by polarizability and relative density. The quality factor (Q×f) exhibited a significant correlation with packing fraction, whereas the temperature coefficient (TCF) of the BESNPLT HECs closely depended on the tolerance factor and bond valence of B-site. The BESNPLT HECs sintered at 1400 °C, demonstrating high relative density (>97%) and optimum microwave dielectric characteristics with TCF = +38.9 ppm/°C, Q×f = 8069 GHz (@6.1 GHz), and εr = 87.26. This study indicates that high-entropy strategy was an efficient route in modifying the dielectric characteristics of tungsten-bronze-type microwave ceramics.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"234 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202386","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}
Irving K. Cashwell, Donovan A. Thomas, Jonathan R. Skuza, Aswini K. Pradhan
This paper demonstrates how the treatment of III-V semiconductor surface affects the number of defects and ensures the conformal growth of the high-k dielectric thin film. We present the electrical properties of an HfO2/InGaAs-based MOS capacitor, in which growth temperatures and surface treatments of the substrate are two key factors that contribute to the uniformity and composition of the HfO2 thin films. A remarkable asymmetry observed in capacitance versus voltage measurements was linked to the interface defects and charge redistribution, as confirmed from X-ray photoelectron spectroscopy. The GaAs substrates that were etched with only NH4OH showed a large frequency dispersion and a higher surface roughness; however, the HfO2 thin films grown on GaAs pre-treated with both NH4OH etching and (NH4)2S passivation steps produced a desirable surface and superior electronic properties.
本文展示了 III-V 族半导体表面处理如何影响缺陷数量并确保高 K 介电薄膜的保形生长。我们介绍了基于 HfO2/InGaAs 的 MOS 电容器的电气特性，其中基底的生长温度和表面处理是影响 HfO2 薄膜均匀性和组成的两个关键因素。X 射线光电子能谱证实，在电容与电压测量中观察到的明显不对称性与界面缺陷和电荷再分布有关。仅用 NH4OH 蚀刻的砷化镓基底显示出较大的频率离散性和较高的表面粗糙度；然而，在砷化镓上生长的 HfO2 薄膜经过 NH4OH 蚀刻和 (NH4)2S 钝化步骤的预处理，产生了理想的表面和优异的电子特性。
{"title":"Electronic Properties of Atomic Layer Deposited HfO2 Thin Films on InGaAs Compared to HfO2/GaAs Semiconductors","authors":"Irving K. Cashwell, Donovan A. Thomas, Jonathan R. Skuza, Aswini K. Pradhan","doi":"10.3390/cryst14090753","DOIUrl":"https://doi.org/10.3390/cryst14090753","url":null,"abstract":"This paper demonstrates how the treatment of III-V semiconductor surface affects the number of defects and ensures the conformal growth of the high-k dielectric thin film. We present the electrical properties of an HfO2/InGaAs-based MOS capacitor, in which growth temperatures and surface treatments of the substrate are two key factors that contribute to the uniformity and composition of the HfO2 thin films. A remarkable asymmetry observed in capacitance versus voltage measurements was linked to the interface defects and charge redistribution, as confirmed from X-ray photoelectron spectroscopy. The GaAs substrates that were etched with only NH4OH showed a large frequency dispersion and a higher surface roughness; however, the HfO2 thin films grown on GaAs pre-treated with both NH4OH etching and (NH4)2S passivation steps produced a desirable surface and superior electronic properties.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"12 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202544","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}
In the pursuit of sustainable energy, magnesium hydride (MgH2) stands out as a promising candidate for hydrogen storage due to its high capacity. Nevertheless, its high thermodynamic stability necessitates elevated operating temperatures, thereby hindering practical applications. To mitigate this limitation, our study employs a defect engineering approach by introducing a mono-vacancy to decrease its thermodynamic stability. Utilizing first-principles density functional theory calculations, we investigate the influence of a mono-vacancy on the structural and electronic properties of MgH2 crystal. Introducing the defect results in a 0.57% contraction of the a/b lattice parameters and a 1.03% expansion along the c-axis, causing lattice distortion. Electronically, the band gap narrows by 0.67 eV, indicating an increase in metallic character. We observe a distinct vacancy-affected zone, characterized by substantial alterations in electron density within a 26.505 Å3 volume and modifications to the potential energy distribution encompassing a 19.514 Å3 volume. The mono-vacancy enhances the polarity of the Mg-H bonds and maximally decreases the bond energy by 0.065 eV. A localized high-energy region of 0.354 eV emerges, functioning as an energy barrier to atomic diffusion. This energy barrier is encompassed by low-energy pathways, potentially facilitating H atom migration within the MgH2 crystal.
在追求可持续能源的过程中，氢化镁（MgH2）因其高容量而成为储氢的理想候选材料。然而，其较高的热力学稳定性要求较高的工作温度，从而阻碍了其实际应用。为了缓解这一限制，我们的研究采用了缺陷工程方法，通过引入单空位来降低其热力学稳定性。利用第一原理密度泛函理论计算，我们研究了单空位对 MgH2 晶体结构和电子特性的影响。缺陷的引入导致 a/b 晶格参数收缩 0.57%，沿 c 轴膨胀 1.03%，从而引起晶格畸变。在电子学上，带隙缩小了 0.67 eV，表明金属特性增强。我们观察到一个明显的空位影响区，其特点是 26.505 Å3 体积内的电子密度发生了重大变化，19.514 Å3 体积内的势能分布也发生了变化。单空位增强了 Mg-H 键的极性，最大程度地降低了键能 0.065 eV。出现了一个 0.354 eV 的局部高能区域，作为原子扩散的能量屏障。这一能量障碍被低能量路径所覆盖，有可能促进 H 原子在 MgH2 晶体内的迁移。
{"title":"Localized Structural and Electronic Perturbations Induced by Mono-Vacancy in MgH2: A Comprehensive First-Principles Investigation","authors":"Lei Bao, Jun Shi, Qichi Le","doi":"10.3390/cryst14090750","DOIUrl":"https://doi.org/10.3390/cryst14090750","url":null,"abstract":"In the pursuit of sustainable energy, magnesium hydride (MgH2) stands out as a promising candidate for hydrogen storage due to its high capacity. Nevertheless, its high thermodynamic stability necessitates elevated operating temperatures, thereby hindering practical applications. To mitigate this limitation, our study employs a defect engineering approach by introducing a mono-vacancy to decrease its thermodynamic stability. Utilizing first-principles density functional theory calculations, we investigate the influence of a mono-vacancy on the structural and electronic properties of MgH2 crystal. Introducing the defect results in a 0.57% contraction of the a/b lattice parameters and a 1.03% expansion along the c-axis, causing lattice distortion. Electronically, the band gap narrows by 0.67 eV, indicating an increase in metallic character. We observe a distinct vacancy-affected zone, characterized by substantial alterations in electron density within a 26.505 Å3 volume and modifications to the potential energy distribution encompassing a 19.514 Å3 volume. The mono-vacancy enhances the polarity of the Mg-H bonds and maximally decreases the bond energy by 0.065 eV. A localized high-energy region of 0.354 eV emerges, functioning as an energy barrier to atomic diffusion. This energy barrier is encompassed by low-energy pathways, potentially facilitating H atom migration within the MgH2 crystal.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"27 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202547","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}
Marco A. Obregón Mendoza, Gabriela Marmolejo Escamilla, Rosario Tavera-Hernández, Rubén Sánchez-Obregón, Rubén A. Toscano, Raúl G. Enríquez
Curcuminoids are widely studied due to their well-recognized therapeutic properties. These molecules are often derivatized with metals, producing their corresponding homoleptic metal complexes. Numerous crystal structures of homoleptic symmetric curcuminoids with physiologically essential metals are known, although the literature lacks reports of homoleptic metal complexes of unsymmetric curcuminoids (or hemi-curcuminoids) as ligands. Three unknowns must be solved when an unsymmetric curcuminoid ligand is reacted with a metal ion: (a) the degree of coordination (MLn); (b) the spatial geometry; and (c) the conformational nature (syn or anti) of the complex. Herein, we report the structure of the anti-isomer of the Zn complex of the hemi-curcuminoid 5-hydroxy-1-(4-methoxyphenyl)hexa-1,4-dien-3-one. While the NMR shows only one set of signals for this homoleptic complex, the unambiguous stereochemistry was established through single-crystal X-ray diffractometry, revealing an anti-hexacoordinated octahedral ML2 structure.
姜黄素因其公认的治疗特性而被广泛研究。这些分子通常会与金属发生衍生物反应，生成相应的同性金属复合物。目前已知有大量同孔对称姜黄素与生理必需金属的晶体结构，但缺乏以不对称姜黄素（或半姜黄素）为配体的同孔金属配合物的文献报道。非对称莪术配体与金属离子反应时，必须解决三个未知问题：（a）配位度（MLn）；（b）空间几何；以及（c）配合物的构象性质（同步或反同步）。在此，我们报告了 5-羟基-1-(4-甲氧基苯基)己-1,4-二烯-3-酮的半莪术苷 Zn 复合物的反异构体结构。虽然核磁共振只显示了这一同色复合物的一组信号，但通过单晶 X 射线衍射测定法确定了其明确的立体化学结构，揭示了反六配位八面体 ML2 结构。
{"title":"The First Crystal Structure of an Anti-Geometric Homoleptic Zinc Complex from an Unsymmetric Curcuminoid Ligand","authors":"Marco A. Obregón Mendoza, Gabriela Marmolejo Escamilla, Rosario Tavera-Hernández, Rubén Sánchez-Obregón, Rubén A. Toscano, Raúl G. Enríquez","doi":"10.3390/cryst14090751","DOIUrl":"https://doi.org/10.3390/cryst14090751","url":null,"abstract":"Curcuminoids are widely studied due to their well-recognized therapeutic properties. These molecules are often derivatized with metals, producing their corresponding homoleptic metal complexes. Numerous crystal structures of homoleptic symmetric curcuminoids with physiologically essential metals are known, although the literature lacks reports of homoleptic metal complexes of unsymmetric curcuminoids (or hemi-curcuminoids) as ligands. Three unknowns must be solved when an unsymmetric curcuminoid ligand is reacted with a metal ion: (a) the degree of coordination (MLn); (b) the spatial geometry; and (c) the conformational nature (syn or anti) of the complex. Herein, we report the structure of the anti-isomer of the Zn complex of the hemi-curcuminoid 5-hydroxy-1-(4-methoxyphenyl)hexa-1,4-dien-3-one. While the NMR shows only one set of signals for this homoleptic complex, the unambiguous stereochemistry was established through single-crystal X-ray diffractometry, revealing an anti-hexacoordinated octahedral ML2 structure.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"167 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202546","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}
Darina Kaisheva, Georgi Kotlarski, Maria Ormanova, Angel Anchev, Vladimir Dunchev, Borislav Stoyanov, Stefan Valkov
In this work, the results from the electron beam welding of copper and Al6082T6 aluminum alloy with a titanium filler are presented. The influence of the filler on the structure and mechanical properties of the welded joint is studied in comparison with one without filler. The X-ray diffraction (XRD) method was used to obtain the phase composition of the welded joints. Scanning electron microscopy (SEM) was used for the study of the microstructure of the welds. Energy-dispersive X-ray spectroscopy (EDX) was applied to investigate the chemical composition. The mechanical properties were studied by means of microhardness measurements and tensile tests. A three-phase structure was obtained in the fusion zone consisting of an aluminum matrix, an intermetallic compound CuAl2, and pure copper. The application of Ti filler significantly decreased the amount of molten copper introduced in the molten pool and the number of intermetallic compounds (IMCs). This improved the strength of the joint; however, some quantity of IMCs was still present in the zone of fusion (FZ), which reflected the microhardness of the samples. The application of a titanium filler resulted in refining the electron beam weld’s structure. The finer structure and the reduced amount of the brittle intermetallic phases has led to an increase in the strength of the joint.
本文介绍了使用钛填充物对铜和 Al6082T6 铝合金进行电子束焊接的结果。与无填充物的焊点相比，研究了填充物对焊点结构和机械性能的影响。采用 X 射线衍射 (XRD) 方法获得了焊点的相组成。扫描电子显微镜（SEM）用于研究焊缝的微观结构。能量色散 X 射线光谱法（EDX）用于研究化学成分。通过显微硬度测量和拉伸试验研究了机械性能。在熔合区获得了由铝基体、金属间化合物 CuAl2 和纯铜组成的三相结构。钛填料的使用大大减少了熔池中铜的含量和金属间化合物（IMC）的数量。这提高了接头的强度；然而，熔合区（FZ）中仍存在一定数量的 IMC，这反映了样品的显微硬度。钛填料的应用使电子束焊缝的结构更加精细。结构的细化和脆性金属间相数量的减少提高了接头的强度。
{"title":"Electron Beam Welding of Copper and Aluminum Alloy with Magnetron Sputtered Titanium Filler","authors":"Darina Kaisheva, Georgi Kotlarski, Maria Ormanova, Angel Anchev, Vladimir Dunchev, Borislav Stoyanov, Stefan Valkov","doi":"10.3390/cryst14090752","DOIUrl":"https://doi.org/10.3390/cryst14090752","url":null,"abstract":"In this work, the results from the electron beam welding of copper and Al6082T6 aluminum alloy with a titanium filler are presented. The influence of the filler on the structure and mechanical properties of the welded joint is studied in comparison with one without filler. The X-ray diffraction (XRD) method was used to obtain the phase composition of the welded joints. Scanning electron microscopy (SEM) was used for the study of the microstructure of the welds. Energy-dispersive X-ray spectroscopy (EDX) was applied to investigate the chemical composition. The mechanical properties were studied by means of microhardness measurements and tensile tests. A three-phase structure was obtained in the fusion zone consisting of an aluminum matrix, an intermetallic compound CuAl2, and pure copper. The application of Ti filler significantly decreased the amount of molten copper introduced in the molten pool and the number of intermetallic compounds (IMCs). This improved the strength of the joint; however, some quantity of IMCs was still present in the zone of fusion (FZ), which reflected the microhardness of the samples. The application of a titanium filler resulted in refining the electron beam weld’s structure. The finer structure and the reduced amount of the brittle intermetallic phases has led to an increase in the strength of the joint.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"20 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202549","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}
Koji Kobayashi, Ryosuke Okuyama, Takeshi Kadono, Ayumi Onaka-Masada, Ryo Hirose, Akihiro Suzuki, Sho Nagatomo, Yoshihiro Koga, Koji Sueoka, Kazunari Kurita
The surface recrystallization model of the fully amorphized C3H5-molecular-ion-implanted silicon (Si) substrate is investigated. Transmission electron microscopy is performed to observe the amorphous/crystalline interface near the C3H5-molecular-ion-implanted Si substrate surface after the subsequent recovery thermal annealing treatment. At a depth of high-concentration carbon of approximately 4.8 × 1020 atoms/cm3, recrystallization from the crystalline template to the surface by solid-phase epitaxial growth is partially delayed, and the activation energy was estimated to be 2.79 ± 0.14 eV. The change in the crystalline fraction of the fully amorphized C3H5-molecular-ion-implanted Si substrate surface is quantitatively evaluated from the binding energy of Si 2p spectra by X-ray photoelectron spectroscopy. Using the Kolmogorov–Johnson–Mehl–Avrami equation, the surface recrystallization of the fully amorphized C3H5-molecular-ion-implanted Si substrate is assumed to proceed two-dimensionally, and its activation energy is obtained as 2.71 ± 0.28 eV without the effect of carbon. Technology computer-aided design (TCAD) process simulations calculate recrystallization under the effect of high-concentration carbon and demonstrate the reach of some crystalline regions to the surface first. In the fully amorphized C3H5-molecular-ion-implanted Si substrate, it is considered that recrystallization is partially delayed due to high-concentration carbon and surface recrystallization proceeds two-dimensionally from some crystalline regions reaching the surface first.
{"title":"Surface Recrystallization Model of Fully Amorphized C3H5-Molecular-Ion-Implanted Silicon Substrate","authors":"Koji Kobayashi, Ryosuke Okuyama, Takeshi Kadono, Ayumi Onaka-Masada, Ryo Hirose, Akihiro Suzuki, Sho Nagatomo, Yoshihiro Koga, Koji Sueoka, Kazunari Kurita","doi":"10.3390/cryst14090748","DOIUrl":"https://doi.org/10.3390/cryst14090748","url":null,"abstract":"The surface recrystallization model of the fully amorphized C3H5-molecular-ion-implanted silicon (Si) substrate is investigated. Transmission electron microscopy is performed to observe the amorphous/crystalline interface near the C3H5-molecular-ion-implanted Si substrate surface after the subsequent recovery thermal annealing treatment. At a depth of high-concentration carbon of approximately 4.8 × 1020 atoms/cm3, recrystallization from the crystalline template to the surface by solid-phase epitaxial growth is partially delayed, and the activation energy was estimated to be 2.79 ± 0.14 eV. The change in the crystalline fraction of the fully amorphized C3H5-molecular-ion-implanted Si substrate surface is quantitatively evaluated from the binding energy of Si 2p spectra by X-ray photoelectron spectroscopy. Using the Kolmogorov–Johnson–Mehl–Avrami equation, the surface recrystallization of the fully amorphized C3H5-molecular-ion-implanted Si substrate is assumed to proceed two-dimensionally, and its activation energy is obtained as 2.71 ± 0.28 eV without the effect of carbon. Technology computer-aided design (TCAD) process simulations calculate recrystallization under the effect of high-concentration carbon and demonstrate the reach of some crystalline regions to the surface first. In the fully amorphized C3H5-molecular-ion-implanted Si substrate, it is considered that recrystallization is partially delayed due to high-concentration carbon and surface recrystallization proceeds two-dimensionally from some crystalline regions reaching the surface first.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"8 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202550","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}
Chun Gao, Yang Zhang, Jingjiang Jiang, Rui Fu, Leiming Du, Xiangnan Pan
Additive manufacturing (AM) or 3D printing is a promising industrial technology that enables rapid prototyping of complex configurations. Powder Bed Fusion (PBF) is one of the most popular AM techniques for metallic materials. Until today, only a few metals and alloys are available for AM, e.g., titanium alloys, the most common of which is Ti-6Al-4V. After optimization of PBF parameters, with or without post processing such as heat treatment or hot isostatic pressing, the printed titanium alloy can easily reach tensile strengths of over 1100 MPa due to the quick cooling of the AM process. However, attributed to the unique features of metallurgical defects and microstructure introduced by this AM process, their fatigue strength has been low, often less than 30% of the tensile strength, especially in very-high-cycle regimes, i.e., failure life beyond 107 cycles. Here, based on our group’s research on the very-high-cycle fatigue (VHCF) of additively manufactured (AMed) Ti-6Al-4V alloys, we have refined the basic quantities of porosity, metallurgical defects, and the AMed microstructure, summarized the main factors limiting their VHCF strengths, and suggested possible ways to improve VHCF performance.
快速成型制造（AM）或三维打印是一种前景广阔的工业技术，可实现复杂结构的快速原型制造。粉末床熔融（PBF）是最流行的金属材料 AM 技术之一。迄今为止，只有少数金属和合金可用于 AM，例如钛合金，其中最常见的是 Ti-6Al-4V 。在优化 PBF 参数后，无论是否进行热处理或热等静压等后处理，由于 AM 工艺的快速冷却，打印出的钛合金都能轻松达到 1100 兆帕以上的抗拉强度。然而，由于这种 AM 工艺引入的冶金缺陷和微观结构的独特性，其疲劳强度一直很低，通常不到拉伸强度的 30%，尤其是在超高循环情况下，即失效寿命超过 107 个循环。在此，根据我们小组对添加剂制造（AMed）Ti-6Al-4V合金的超高循环疲劳（VHCF）的研究，我们完善了孔隙率、冶金缺陷和AMed微结构的基本量，总结了限制其VHCF强度的主要因素，并提出了改善VHCF性能的可能方法。
{"title":"Research Viewpoint on Performance Enhancement for Very-High-Cycle Fatigue of Ti-6Al-4V Alloys via Laser-Based Powder Bed Fusion","authors":"Chun Gao, Yang Zhang, Jingjiang Jiang, Rui Fu, Leiming Du, Xiangnan Pan","doi":"10.3390/cryst14090749","DOIUrl":"https://doi.org/10.3390/cryst14090749","url":null,"abstract":"Additive manufacturing (AM) or 3D printing is a promising industrial technology that enables rapid prototyping of complex configurations. Powder Bed Fusion (PBF) is one of the most popular AM techniques for metallic materials. Until today, only a few metals and alloys are available for AM, e.g., titanium alloys, the most common of which is Ti-6Al-4V. After optimization of PBF parameters, with or without post processing such as heat treatment or hot isostatic pressing, the printed titanium alloy can easily reach tensile strengths of over 1100 MPa due to the quick cooling of the AM process. However, attributed to the unique features of metallurgical defects and microstructure introduced by this AM process, their fatigue strength has been low, often less than 30% of the tensile strength, especially in very-high-cycle regimes, i.e., failure life beyond 107 cycles. Here, based on our group’s research on the very-high-cycle fatigue (VHCF) of additively manufactured (AMed) Ti-6Al-4V alloys, we have refined the basic quantities of porosity, metallurgical defects, and the AMed microstructure, summarized the main factors limiting their VHCF strengths, and suggested possible ways to improve VHCF performance.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"11 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202552","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}
In recent years, cerium dioxide (CeO2) has attracted considerable attention owing to its remarkable performance in various applications, including photocatalysis, fuel cells, and catalysis. This study explores the effect of nickel (Ni) doping on the structural, thermal, and chemical properties of CeO2 nanorods, particularly focusing on oxygen vacancy-related phenomena. Utilizing X-ray powder diffraction (XRD), alterations in crystal structure and peak shifts were observed, indicating successful Ni doping and the formation of Ni2O3 at higher doping levels, likely due to non-equilibrium reactions. Thermal gravimetric analysis (TGA) revealed changes in oxygen release mechanisms, with increasing Ni doping resulting in the release of lattice oxygen at lower temperatures. Raman spectroscopy corroborated these findings by identifying characteristic peaks associated with oxygen vacancies, facilitating the assessment of Ni doping levels. Ni-doped CeO2 can catalyze the ultrasonic degradation of methylene blue, which has good application prospects for catalytic ultrasonic degradation of organic pollutants. Overall, this study underscores the substantial impact of Ni doping on CeO2 nanorods, shedding light on tailored catalytic applications through the modulation of oxygen vacancies while preserving the nanorod morphology.
近年来，二氧化铈（CeO2）因其在光催化、燃料电池和催化等各种应用中的卓越性能而备受关注。本研究探讨了掺杂镍（Ni）对二氧化铈纳米棒的结构、热和化学特性的影响，尤其关注与氧空位相关的现象。利用 X 射线粉末衍射 (XRD)，观察到晶体结构的改变和峰值移动，表明掺杂镍成功，并且在掺杂水平较高时形成了 Ni2O3，这可能是由于非平衡反应造成的。热重分析（TGA）显示了氧释放机制的变化，掺杂镍量的增加导致晶格氧在较低温度下释放。拉曼光谱通过识别与氧空位相关的特征峰证实了这些发现，从而有助于评估掺镍水平。掺杂镍的 CeO2 可以催化亚甲基蓝的超声降解，在催化超声降解有机污染物方面具有良好的应用前景。总之，本研究强调了掺杂镍对 CeO2 纳米棒的重大影响，通过在保持纳米棒形态的同时调节氧空位，为定制催化应用提供了启示。
{"title":"Influence of Ni Doping on Oxygen Vacancy-Induced Changes in Structural and Chemical Properties of CeO2 Nanorods","authors":"Yuanzheng Zhu, Weixia Wang, Gejunxiang Chen, Huyi Li, Yuedie Zhang, Chang Liu, Hao Wang, Ping Cheng, Chunguang Chen, Gimyeong Seong","doi":"10.3390/cryst14080746","DOIUrl":"https://doi.org/10.3390/cryst14080746","url":null,"abstract":"In recent years, cerium dioxide (CeO2) has attracted considerable attention owing to its remarkable performance in various applications, including photocatalysis, fuel cells, and catalysis. This study explores the effect of nickel (Ni) doping on the structural, thermal, and chemical properties of CeO2 nanorods, particularly focusing on oxygen vacancy-related phenomena. Utilizing X-ray powder diffraction (XRD), alterations in crystal structure and peak shifts were observed, indicating successful Ni doping and the formation of Ni2O3 at higher doping levels, likely due to non-equilibrium reactions. Thermal gravimetric analysis (TGA) revealed changes in oxygen release mechanisms, with increasing Ni doping resulting in the release of lattice oxygen at lower temperatures. Raman spectroscopy corroborated these findings by identifying characteristic peaks associated with oxygen vacancies, facilitating the assessment of Ni doping levels. Ni-doped CeO2 can catalyze the ultrasonic degradation of methylene blue, which has good application prospects for catalytic ultrasonic degradation of organic pollutants. Overall, this study underscores the substantial impact of Ni doping on CeO2 nanorods, shedding light on tailored catalytic applications through the modulation of oxygen vacancies while preserving the nanorod morphology.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"4 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202553","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}
High-sensitivity magnetic sensors are fundamental components in fields such as biomedicine and non-destructive testing. Flux concentration technology enhances the sensitivity of magnetic sensors by amplifying the magnetic field to be measured, making it the most effective method to improve the magnetic field resolution of magnetic sensors. Superconductors and high-permeability soft magnetic materials exhibit completely different magnetic effects. The former possesses complete diamagnetism, while the latter has extremely high magnetic permeability. Both types of materials can be used to fabricate flux concentrators. This paper compares superconducting and soft magnetic flux concentration technologies through theoretical simulations and experiments, investigating the impact of different structural parameters on the magnetic field amplification performance of superconducting and soft magnetic concentrators. This research is significant for the development of magnetic focusing technology and its applications in weak magnetic detection and other fields.
{"title":"Magnetic Flux Concentration Technology Based on Soft Magnets and Superconductors","authors":"Yue Wu, Liye Xiao, Siyuan Han, Jiamin Chen","doi":"10.3390/cryst14080747","DOIUrl":"https://doi.org/10.3390/cryst14080747","url":null,"abstract":"High-sensitivity magnetic sensors are fundamental components in fields such as biomedicine and non-destructive testing. Flux concentration technology enhances the sensitivity of magnetic sensors by amplifying the magnetic field to be measured, making it the most effective method to improve the magnetic field resolution of magnetic sensors. Superconductors and high-permeability soft magnetic materials exhibit completely different magnetic effects. The former possesses complete diamagnetism, while the latter has extremely high magnetic permeability. Both types of materials can be used to fabricate flux concentrators. This paper compares superconducting and soft magnetic flux concentration technologies through theoretical simulations and experiments, investigating the impact of different structural parameters on the magnetic field amplification performance of superconducting and soft magnetic concentrators. This research is significant for the development of magnetic focusing technology and its applications in weak magnetic detection and other fields.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":"14 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202555","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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