Marko Radulović, Xingyu Li, Goran J Djuričić, Jelena Milovanović, Nataša Todorović Raković, Tijana Vujasinović, Dušan Banovac, Ksenija Kanjer
Tumor histomorphology is crucial for the prognostication of breast cancer outcomes because it contains histological, cellular, and molecular tumor heterogeneity related to metastatic potential. To enhance breast cancer prognosis, we aimed to apply radiomics analysis-traditionally used in 3D scans-to 2D histopathology slides. This study tested radiomics analysis in a cohort of 92 breast tumor specimens for outcome prognosis, addressing -omics dimensionality by comparing models with moderate and high feature counts, using least absolute shrinkage and selection operator for feature selection and machine learning for prognostic modeling. In the test folds, models with radiomics features [area under the curves (AUCs) range 0.799-0.823] significantly outperformed the benchmark model, which only included clinicopathological (CP) parameters (AUC = 0.584). The moderate-dimensionality model with 11 CP + 93 radiomics features matched the performance of the highly dimensional models with 1,208 radiomics or 11 CP + 1,208 radiomics features, showing average AUCs of 0.823, 0.799, and 0.807 and accuracies of 79.8, 79.3, and 76.6%, respectively. In conclusion, our application of deep texture radiomics analysis to 2D histopathology showed strong prognostic performance with a moderate-dimensionality model, surpassing a benchmark based on standard CP parameters, indicating that this deep texture histomics approach could potentially become a valuable prognostic tool.
{"title":"Bridging Histopathology and Radiomics Toward Prognosis of Metastasis in Early Breast Cancer.","authors":"Marko Radulović, Xingyu Li, Goran J Djuričić, Jelena Milovanović, Nataša Todorović Raković, Tijana Vujasinović, Dušan Banovac, Ksenija Kanjer","doi":"10.1093/mam/ozae057","DOIUrl":"10.1093/mam/ozae057","url":null,"abstract":"<p><p>Tumor histomorphology is crucial for the prognostication of breast cancer outcomes because it contains histological, cellular, and molecular tumor heterogeneity related to metastatic potential. To enhance breast cancer prognosis, we aimed to apply radiomics analysis-traditionally used in 3D scans-to 2D histopathology slides. This study tested radiomics analysis in a cohort of 92 breast tumor specimens for outcome prognosis, addressing -omics dimensionality by comparing models with moderate and high feature counts, using least absolute shrinkage and selection operator for feature selection and machine learning for prognostic modeling. In the test folds, models with radiomics features [area under the curves (AUCs) range 0.799-0.823] significantly outperformed the benchmark model, which only included clinicopathological (CP) parameters (AUC = 0.584). The moderate-dimensionality model with 11 CP + 93 radiomics features matched the performance of the highly dimensional models with 1,208 radiomics or 11 CP + 1,208 radiomics features, showing average AUCs of 0.823, 0.799, and 0.807 and accuracies of 79.8, 79.3, and 76.6%, respectively. In conclusion, our application of deep texture radiomics analysis to 2D histopathology showed strong prognostic performance with a moderate-dimensionality model, surpassing a benchmark based on standard CP parameters, indicating that this deep texture histomics approach could potentially become a valuable prognostic tool.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141555180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deformation bands are common constituents of porous clastic fluid reservoirs. Various techniques have been used to study deformation band structure and the associated changes in porosity and permeability. However, the use of electron backscatter diffraction technique is limited. Thus, more information is needed regarding the crystallographic relationships between detrital crystals, which can significantly impact reservoir rock quality. We employ microscopic and microstructural investigation techniques to analyze the influence of cataclastic deformation bands on pore space. Porosity measurements of the Cretaceous Ilhas Group sandstone in NE Brazil, obtained through computerized microtomography, indicate that the undeformed domains exhibit a total porosity of up to 13%. In contrast, this porosity is slightly over 1% in the deformation bands. Scanning electron microscopy analyses revealed the presence of grain fragmentation and dissolution microstructures, along with cement-filling pre-existing pores. The electron backscatter diffraction analyses indicated extensive grain fragmentation and minimal contribution from intracrystalline plasticity as a deformation mechanism. However, the c axes of quartz crystals roughly align parallel to the orientation of the deformation band. In summary, we have confirmed and quantified the internal changes in a deformation band cluster, with grain size reduction and associated compaction as the main mechanism supported by quartz cementation.
变形带是多孔碎屑岩储层的常见成分。研究形变带结构以及相关的孔隙度和渗透率变化已经使用了多种技术。然而,电子反向散射衍射技术的使用受到限制。因此,我们需要更多有关碎屑晶体之间结晶关系的信息,这可能会对储层岩石质量产生重大影响。我们采用显微镜和微结构调查技术来分析碎屑岩变形带对孔隙空间的影响。通过计算机显微层析成像技术对巴西东北部白垩纪伊尔哈斯组砂岩进行的孔隙度测量表明,未变形域的总孔隙度高达 13%。相比之下,变形带的孔隙率略高于 1%。扫描电子显微镜分析显示,存在晶粒破碎和溶解微结构,以及水泥填充原有孔隙。电子反向散射衍射分析表明了广泛的晶粒破碎,而晶内塑性作为变形机制的作用微乎其微。不过,石英晶体的 c 轴大致与变形带的方向平行。总之,我们证实并量化了变形带团的内部变化,晶粒尺寸减小和相关压实是石英胶结支持的主要机制。
{"title":"Application of the EBSD Technique in the Study of Porosity and Permeability in Deformation Bands in Sandstone.","authors":"Flávia Priscila Souza Afonso, Leonardo Lagoeiro, Haakon Fossen, Paola Ferreira Barbosa, Celeste Bertassoni Pinto, Camila Gomes Peçanha de Souza","doi":"10.1093/mam/ozae070","DOIUrl":"10.1093/mam/ozae070","url":null,"abstract":"<p><p>Deformation bands are common constituents of porous clastic fluid reservoirs. Various techniques have been used to study deformation band structure and the associated changes in porosity and permeability. However, the use of electron backscatter diffraction technique is limited. Thus, more information is needed regarding the crystallographic relationships between detrital crystals, which can significantly impact reservoir rock quality. We employ microscopic and microstructural investigation techniques to analyze the influence of cataclastic deformation bands on pore space. Porosity measurements of the Cretaceous Ilhas Group sandstone in NE Brazil, obtained through computerized microtomography, indicate that the undeformed domains exhibit a total porosity of up to 13%. In contrast, this porosity is slightly over 1% in the deformation bands. Scanning electron microscopy analyses revealed the presence of grain fragmentation and dissolution microstructures, along with cement-filling pre-existing pores. The electron backscatter diffraction analyses indicated extensive grain fragmentation and minimal contribution from intracrystalline plasticity as a deformation mechanism. However, the c axes of quartz crystals roughly align parallel to the orientation of the deformation band. In summary, we have confirmed and quantified the internal changes in a deformation band cluster, with grain size reduction and associated compaction as the main mechanism supported by quartz cementation.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141897776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Materials characterization using electron backscatter diffraction (EBSD) requires indexing the orientation of the measured region from Kikuchi patterns. The quality of Kikuchi patterns can degrade due to pattern overlaps arising from two or more orientations, in the presence of defects or grain boundaries. In this work, we employ constrained nonnegative matrix factorization to segment a microstructure with small grain misorientations, (<1∘), and predict the amount of pattern overlap. First, we implement the method on mixed simulated patterns-that replicates a pattern overlap scenario, and demonstrate the resolution limit of pattern mixing or factorization resolution using a weight metric. Subsequently, we segment a single-crystal dendritic microstructure and compare the results with high-resolution EBSD. By utilizing weight metrics across a low-angle grain boundary, we demonstrate how very small misorientations/low-angle grain boundaries can be resolved at a pixel level. Our approach constitutes a versatile and robust tool, complementing other fast indexing methods for microstructure characterization.
{"title":"Employing Constrained Nonnegative Matrix Factorization for Microstructure Segmentation.","authors":"Ashish Chauniyal, Pascal Thome, Markus Stricker","doi":"10.1093/mam/ozae056","DOIUrl":"10.1093/mam/ozae056","url":null,"abstract":"<p><p>Materials characterization using electron backscatter diffraction (EBSD) requires indexing the orientation of the measured region from Kikuchi patterns. The quality of Kikuchi patterns can degrade due to pattern overlaps arising from two or more orientations, in the presence of defects or grain boundaries. In this work, we employ constrained nonnegative matrix factorization to segment a microstructure with small grain misorientations, (<1∘), and predict the amount of pattern overlap. First, we implement the method on mixed simulated patterns-that replicates a pattern overlap scenario, and demonstrate the resolution limit of pattern mixing or factorization resolution using a weight metric. Subsequently, we segment a single-crystal dendritic microstructure and compare the results with high-resolution EBSD. By utilizing weight metrics across a low-angle grain boundary, we demonstrate how very small misorientations/low-angle grain boundaries can be resolved at a pixel level. Our approach constitutes a versatile and robust tool, complementing other fast indexing methods for microstructure characterization.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141559122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The controlled creation and manipulation of defects in 2D materials has become increasingly popular as a means to design and tune new material functionalities. However, defect characterization by direct atomic-scale imaging is often severely limited by surface contamination due to a blanket of hydrocarbons. Thus, analysis techniques that can characterize atomic-scale defects despite the contamination layer are advantageous. In this work, we take inspiration from X-ray absorption spectroscopy and use broad-beam electron energy loss spectroscopy (EELS) to characterize defect structures in 2D hexagonal boron nitride (hBN) based on averaged fine structure in the boron K-edge. Since EELS is performed in a transmission electron microscope (TEM), imaging can be performed in-situ to assess contamination levels and other factors such as tears in the fragile 2D sheets, which can affect the spectroscopic analysis. We demonstrate the TEM-EELS technique for 2D hBN samples irradiated with different ion types and doses, finding spectral signatures indicative of boron-oxygen bonding that can be used as a measure of sample defectiveness depending on the ion beam treatment. We propose that even in cases where surface contamination has been mitigated, the averaging-based TEM-EELS technique can be useful for efficient sample surveys to support atomically resolved EELS experiments.
作为设计和调整新材料功能的一种手段,在二维材料中可控地制造和操纵缺陷已变得越来越流行。然而,通过直接原子尺度成像进行缺陷表征往往会受到碳氢化合物覆盖层造成的表面污染的严重限制。因此,尽管存在污染层,但仍能表征原子尺度缺陷的分析技术是非常有优势的。在这项工作中,我们从 X 射线吸收光谱学中汲取灵感,利用宽束电子能量损失光谱(EELS),根据硼 K 边的平均精细结构来表征二维六方氮化硼(hBN)中的缺陷结构。由于 EELS 是在透射电子显微镜(TEM)中进行的,因此可以在原位进行成像,以评估污染程度和其他因素,如脆弱的二维薄片中的裂缝,这些都会影响光谱分析。我们对经过不同离子类型和剂量辐照的二维 hBN 样品演示了 TEM-EELS 技术,发现了指示硼-氧键合的光谱特征,根据离子束处理的不同,这些特征可用作样品缺陷的衡量标准。我们建议,即使在表面污染已得到缓解的情况下,基于平均化的 TEM-EELS 技术也可用于高效的样品调查,以支持原子分辨 EELS 实验。
{"title":"Probing Defectivity Beneath the Hydrocarbon Blanket in 2D hBN Using TEM-EELS.","authors":"Dana O Byrne, Jim Ciston, Frances I Allen","doi":"10.1093/mam/ozae064","DOIUrl":"10.1093/mam/ozae064","url":null,"abstract":"<p><p>The controlled creation and manipulation of defects in 2D materials has become increasingly popular as a means to design and tune new material functionalities. However, defect characterization by direct atomic-scale imaging is often severely limited by surface contamination due to a blanket of hydrocarbons. Thus, analysis techniques that can characterize atomic-scale defects despite the contamination layer are advantageous. In this work, we take inspiration from X-ray absorption spectroscopy and use broad-beam electron energy loss spectroscopy (EELS) to characterize defect structures in 2D hexagonal boron nitride (hBN) based on averaged fine structure in the boron K-edge. Since EELS is performed in a transmission electron microscope (TEM), imaging can be performed in-situ to assess contamination levels and other factors such as tears in the fragile 2D sheets, which can affect the spectroscopic analysis. We demonstrate the TEM-EELS technique for 2D hBN samples irradiated with different ion types and doses, finding spectral signatures indicative of boron-oxygen bonding that can be used as a measure of sample defectiveness depending on the ion beam treatment. We propose that even in cases where surface contamination has been mitigated, the averaging-based TEM-EELS technique can be useful for efficient sample surveys to support atomically resolved EELS experiments.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141727431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jasmine Eshun, Natalie C Lamar, Sinan G Aksoy, Sarah Akers, Benjamin Garcia, Heather Cunningham, George Chin, Jenna A Bilbrey
Automated particle analysis (APA) provides a vast amount of compositional data via energy-dispersive X-ray spectroscopy along with size and shape data via scanning electron microscopy for individual particles in a sample. In many instances, APA data are leveraged to support identification of the source of a sample based on the detection of particles of a specific composition. Often, the particles that provide context make up a minuscule portion of the sample. Additionally, the interpretation of complex samples can be difficult due to the diversity of compositions both in the mixture and within a particle. In this work, we demonstrate a method to compute and cluster similarity graphs that describe inter-particle relationships within a sample using a multi-modal few-shot learning neural network. As a proof-of-concept, we show that samples known to have been exposed to gunshot residue can be distinguished from samples occasionally mistaken for gunshot residue. Our workflow builds upon standard APA techniques and data processing methods to unveil additional information in a readily interpretable and quantitatively comparable format.
自动颗粒分析(APA)通过能量色散 X 射线光谱提供大量成分数据,并通过扫描电子显微镜提供样品中单个颗粒的尺寸和形状数据。在许多情况下,APA 数据可用于根据特定成分颗粒的检测结果来识别样品来源。通常情况下,提供背景信息的颗粒只占样品的极小部分。此外,由于混合物和颗粒内部成分的多样性,对复杂样品的解释也很困难。在这项工作中,我们展示了一种计算和聚类相似性图谱的方法,该图谱使用多模态少量学习神经网络来描述样本中粒子间的关系。作为概念验证,我们展示了已知接触过枪击残留物的样本可以与偶尔被误认为枪击残留物的样本区分开来。我们的工作流程以标准 APA 技术和数据处理方法为基础,以易于解释和定量比较的形式揭示更多信息。
{"title":"Identifying Sample Provenance From SEM/EDS Automated Particle Analysis via Few-Shot Learning Coupled With Similarity Graph Clustering.","authors":"Jasmine Eshun, Natalie C Lamar, Sinan G Aksoy, Sarah Akers, Benjamin Garcia, Heather Cunningham, George Chin, Jenna A Bilbrey","doi":"10.1093/mam/ozae068","DOIUrl":"10.1093/mam/ozae068","url":null,"abstract":"<p><p>Automated particle analysis (APA) provides a vast amount of compositional data via energy-dispersive X-ray spectroscopy along with size and shape data via scanning electron microscopy for individual particles in a sample. In many instances, APA data are leveraged to support identification of the source of a sample based on the detection of particles of a specific composition. Often, the particles that provide context make up a minuscule portion of the sample. Additionally, the interpretation of complex samples can be difficult due to the diversity of compositions both in the mixture and within a particle. In this work, we demonstrate a method to compute and cluster similarity graphs that describe inter-particle relationships within a sample using a multi-modal few-shot learning neural network. As a proof-of-concept, we show that samples known to have been exposed to gunshot residue can be distinguished from samples occasionally mistaken for gunshot residue. Our workflow builds upon standard APA techniques and data processing methods to unveil additional information in a readily interpretable and quantitatively comparable format.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141860221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Probe formation in scanning electron microscope (SEM) is often reduced to objective lens action modeling based on a point-spread function or Fourier transforms. In this study, we present the first complete wave optical modeling of the whole SEM column based on plane-by-plane propagation of the electron beam wavefunction without simplifying the optical system. We identify the challenges in plane-by-plane beam propagation and show how sampling limitations produce aliased results. Through a careful selection and combination of propagators, we have developed a general wave optical propagation method that is able to overcome the aliasing problem to achieve the appropriate probe widths. Using a two-step propagator, we show that it is possible to model the electron beam distribution throughout the column from the virtual source plane to the specimen plane. We also show that our results from the wave optical simulations are consistent with the geometrical theory of probe formation. Finally, as a direct application of this method, we demonstrated that the combined effect of aberrations in the condenser lens and the probe forming objective lens cannot be accurately represented using only the objective lens. Designing beam shaping experiments and studying the effect of partial coherence can be some novel applications.
{"title":"Wave Optical Modeling of the SEM Column From Source to Specimen.","authors":"Surya Kamal, Yongjian Zhou, Zizhou Gong","doi":"10.1093/mam/ozae072","DOIUrl":"https://doi.org/10.1093/mam/ozae072","url":null,"abstract":"<p><p>Probe formation in scanning electron microscope (SEM) is often reduced to objective lens action modeling based on a point-spread function or Fourier transforms. In this study, we present the first complete wave optical modeling of the whole SEM column based on plane-by-plane propagation of the electron beam wavefunction without simplifying the optical system. We identify the challenges in plane-by-plane beam propagation and show how sampling limitations produce aliased results. Through a careful selection and combination of propagators, we have developed a general wave optical propagation method that is able to overcome the aliasing problem to achieve the appropriate probe widths. Using a two-step propagator, we show that it is possible to model the electron beam distribution throughout the column from the virtual source plane to the specimen plane. We also show that our results from the wave optical simulations are consistent with the geometrical theory of probe formation. Finally, as a direct application of this method, we demonstrated that the combined effect of aberrations in the condenser lens and the probe forming objective lens cannot be accurately represented using only the objective lens. Designing beam shaping experiments and studying the effect of partial coherence can be some novel applications.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142000391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examines the egg-laying behavior and egg morphology of Hydrometra stagnorum (Linnaeus, 1753) (Gerromorpha: Heteroptera) to provide ecofaunistic information about the species. Newly recorded H. stagnorum samples were collected from the Karabük province of Western Black Sea region of Türkiye. Physicochemical parameters of the water were also recorded. The morphology and egg-laying behavior of H. stagnorum eggs were identified using a stereo, light and electron microscopy. Mature eggs were observed to be blackish dark brown in color. The study reveals distinctive characteristics of the egg structure and micropyle areas, which may contribute to the classification of the species at the subfamily level. Additionally, it was found that H. stagnorum inhabits high-quality waters.
本研究考察了水螅(Hydrometra stagnorum)(林尼厄斯,1753 年)(Gerromorpha:异翅目)的产卵行为和卵形态,以提供有关该物种的生态环境信息。从土耳其西黑海地区的卡拉比克省采集了新记录的水螅样本。同时还记录了水体的理化参数。使用立体、光学和电子显微镜鉴定了死水蛙卵的形态和产卵行为。观察到成熟的卵呈黑褐色。该研究揭示了卵结构和微孔区域的独特特征,这可能有助于在亚科水平上对该物种进行分类。此外,研究还发现 H. stagnorum 栖息于优质水域。
{"title":"Ecofaunistic Study and Egg Morphology: Egg Laying Behavior of Hydrometra stagnorum (Linnaeus, 1753) (Gerromorpha: Heteroptera) Newly Recorded From the Karabük Province of Western Black Sea (Türkiye).","authors":"Hakan Ozdamar, Suat Kiyak","doi":"10.1093/mam/ozae073","DOIUrl":"https://doi.org/10.1093/mam/ozae073","url":null,"abstract":"<p><p>This study examines the egg-laying behavior and egg morphology of Hydrometra stagnorum (Linnaeus, 1753) (Gerromorpha: Heteroptera) to provide ecofaunistic information about the species. Newly recorded H. stagnorum samples were collected from the Karabük province of Western Black Sea region of Türkiye. Physicochemical parameters of the water were also recorded. The morphology and egg-laying behavior of H. stagnorum eggs were identified using a stereo, light and electron microscopy. Mature eggs were observed to be blackish dark brown in color. The study reveals distinctive characteristics of the egg structure and micropyle areas, which may contribute to the classification of the species at the subfamily level. Additionally, it was found that H. stagnorum inhabits high-quality waters.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141917110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Identifying clusters of solute atoms in a matrix of solvent atoms helps to understand precipitation phenomena in alloys, for example, during the age hardening of certain aluminum alloys. Atom probe tomography datasets can deliver such information, provided that appropriate cluster identification routines are available. We investigate algorithms based on the local composition of the neighborhood of solute atoms and compare them with traditional approaches based on the local solute number density, such as the maximum separation distance method. For an ideal solid solution, the pair correlation functions of the kth nearest solute atom in the coordination number representation are derived, and the percolation threshold and the size distribution of clusters are studied. A criterion for selecting optimal control parameters based on maximizing the phase separation by the degree of clustering is proposed for a two-phase system. A map of phase compositions accessible for cluster analysis is constructed. The coordination number approach reduces the influence of density variations commonly observed in atom probe tomography data. Finally, a practical cluster analysis technique applied to the early stages of aluminum alloy aging is described.
识别溶剂原子矩阵中的溶质原子簇有助于了解合金中的沉淀现象,例如某些铝合金在时效硬化过程中的沉淀现象。原子探针层析成像数据集可提供此类信息,前提是具备适当的原子团识别程序。我们研究了基于溶质原子邻域局部组成的算法,并将其与基于局部溶质数量密度的传统方法(如最大分离距离法)进行了比较。对于理想固溶体,我们推导出了配位数表示中第 k 个最近溶质原子的成对相关函数,并研究了渗流阈值和簇的大小分布。针对两相体系,提出了基于聚类程度最大化相分离的最佳控制参数选择标准。构建了可用于聚类分析的相组成图。配位数方法减少了原子探针断层扫描数据中常见的密度变化的影响。最后,介绍了一种应用于铝合金老化早期阶段的实用聚类分析技术。
{"title":"A Concept of Local Coordination Number for the Characterization of Solute Clusters within Atom Probe Tomography Data.","authors":"Mykola Lazarev, John Banhart","doi":"10.1093/mam/ozae074","DOIUrl":"https://doi.org/10.1093/mam/ozae074","url":null,"abstract":"<p><p>Identifying clusters of solute atoms in a matrix of solvent atoms helps to understand precipitation phenomena in alloys, for example, during the age hardening of certain aluminum alloys. Atom probe tomography datasets can deliver such information, provided that appropriate cluster identification routines are available. We investigate algorithms based on the local composition of the neighborhood of solute atoms and compare them with traditional approaches based on the local solute number density, such as the maximum separation distance method. For an ideal solid solution, the pair correlation functions of the kth nearest solute atom in the coordination number representation are derived, and the percolation threshold and the size distribution of clusters are studied. A criterion for selecting optimal control parameters based on maximizing the phase separation by the degree of clustering is proposed for a two-phase system. A map of phase compositions accessible for cluster analysis is constructed. The coordination number approach reduces the influence of density variations commonly observed in atom probe tomography data. Finally, a practical cluster analysis technique applied to the early stages of aluminum alloy aging is described.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141897775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The accuracy of carbon composition measurement of carbide precipitates in steel or other alloys is limited by the evaporation characteristics of carbon and the performance of current detector systems. Carbon evaporates in a higher fraction as clustered ions leading to detector pile-up during so-called multiple hits. To achieve higher accuracy, a grid was positioned behind the local electrode, reducing the detection efficiency from 52 to 7% and thereby reducing the fraction of multi-hit events. This work confirms the preferential loss of carbon due to detector pile-up. Furthermore, we demonstrate that the newer generation of commercial atom probe instruments displays somewhat higher discrepancy of carbon composition than previous generations. The reason for this might be different laser-matter interaction leading to less metal ions in multi-hit events.
{"title":"Revisiting Compositional Accuracy of Carbides Using a Decreased Detector Efficiency in a LEAP 6000 XR Atom Probe Instrument.","authors":"Severin Jakob, Mattias Thuvander","doi":"10.1093/mam/ozae069","DOIUrl":"https://doi.org/10.1093/mam/ozae069","url":null,"abstract":"<p><p>The accuracy of carbon composition measurement of carbide precipitates in steel or other alloys is limited by the evaporation characteristics of carbon and the performance of current detector systems. Carbon evaporates in a higher fraction as clustered ions leading to detector pile-up during so-called multiple hits. To achieve higher accuracy, a grid was positioned behind the local electrode, reducing the detection efficiency from 52 to 7% and thereby reducing the fraction of multi-hit events. This work confirms the preferential loss of carbon due to detector pile-up. Furthermore, we demonstrate that the newer generation of commercial atom probe instruments displays somewhat higher discrepancy of carbon composition than previous generations. The reason for this might be different laser-matter interaction leading to less metal ions in multi-hit events.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141860223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Levi Tegg, Ingrid E McCarroll, Se-Ho Kim, Renelle Dubosq, Eric V Woods, Ayman A El-Zoka, Baptiste Gault, Julie M Cairney
The application of atom probe tomography (APT) to frozen liquids is limited by difficulties in specimen preparation. Here, we report on the use of nanoporous Cu needles as a physical framework to hold water ice for investigation using APT. Nanoporous Cu needles are prepared by electropolishing and dealloying Cu-Mn matchstick precursors. Cryogenic scanning electron microscopy and focused ion beam milling reveal a hierarchical, dendritic, highly wettable microstructure. The atom probe mass spectrum is dominated by peaks of Cu+ and H(H2O)n+ up to n ≤ 3, and the reconstructed volume shows the protrusion of a Cu ligament into an ice-filled pore. The continuous Cu ligament network electrically connects the apex to the cryostage, leading to an enhanced electric field at the apex and increased cooling, both of which simplify the mass spectrum compared to previous reports.
{"title":"Analysis of Water Ice in Nanoporous Copper Needles Using Cryo Atom Probe Tomography.","authors":"Levi Tegg, Ingrid E McCarroll, Se-Ho Kim, Renelle Dubosq, Eric V Woods, Ayman A El-Zoka, Baptiste Gault, Julie M Cairney","doi":"10.1093/mam/ozae062","DOIUrl":"https://doi.org/10.1093/mam/ozae062","url":null,"abstract":"<p><p>The application of atom probe tomography (APT) to frozen liquids is limited by difficulties in specimen preparation. Here, we report on the use of nanoporous Cu needles as a physical framework to hold water ice for investigation using APT. Nanoporous Cu needles are prepared by electropolishing and dealloying Cu-Mn matchstick precursors. Cryogenic scanning electron microscopy and focused ion beam milling reveal a hierarchical, dendritic, highly wettable microstructure. The atom probe mass spectrum is dominated by peaks of Cu+ and H(H2O)n+ up to n ≤ 3, and the reconstructed volume shows the protrusion of a Cu ligament into an ice-filled pore. The continuous Cu ligament network electrically connects the apex to the cryostage, leading to an enhanced electric field at the apex and increased cooling, both of which simplify the mass spectrum compared to previous reports.</p>","PeriodicalId":18625,"journal":{"name":"Microscopy and Microanalysis","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141723908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}