Micron最新文献

{"title":"Low-voltage single-atom electron microscopy with carbon-based nanomaterials","authors":"","doi":"10.1016/j.micron.2024.103706","DOIUrl":"10.1016/j.micron.2024.103706","url":null,"abstract":"<div><p>The properties of materials are strongly correlated with their atomic scale structures. Achieving a comprehensive understanding of the atomic-scale structure-property relationship requires advancements of imaging and spectroscopy techniques. Aberration-corrected scanning transmission electron microscopy (STEM) has seen rapid development over the past decades and is now routinely employed for atomic-scale characterization. However, quantitative STEM imaging and spectroscopy analysis at the single-atom level is challenging due to the extremely weak signals generated from individual atom, thus imposing stringent requirements for analysis sensitivity. This review discusses the development and application of low-voltage STEM techniques with single-atom sensitivity, primarily based on recent research presented on an invited talk at the 5th 2D23 SALVE Symposium, including annular dark-field (ADF) imaging, functional imaging and electron energy-loss spectroscopy (EELS) analysis. Carbon-based nanomaterials were chosen as model systems for demonstrating the capabilities of single-atom STEM imaging and EELS analysis, due to their structural stability under low accelerating voltages and their rich physical and chemical properties. Moreover, this review summarizes recent advancements and applications of low-voltage single-atom STEM imaging and spectroscopy in the study of functional materials and discusses prospects for future developments.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low defect density in MoS2 monolayers grown on Au(111) by metal-organic chemical vapor deposition","authors":"","doi":"10.1016/j.micron.2024.103708","DOIUrl":"10.1016/j.micron.2024.103708","url":null,"abstract":"<div><p>Monolayers of transition metal dichalcogenides (TMDs) possess high potential for applications in novel electronic and optoelectronic devices and therefore the development of methods for their scalable growth is of high importance. Among different suggested approaches, metal-organic chemical vapor deposition (MOCVD) is the most promising one for technological applications because of its lower growth temperature compared to the most other methods, <em>e.g.</em>, conventional chemical vapor or atomic layer deposition (CVD, ALD). Here we demonstrate for the first time the epitaxial growth of MoS₂ monolayers on Au(111) by MOCVD at 450 °C. We confirm the high quality of the grown TMD monolayers down to the atomic scale using several complementary methods. These include Raman spectroscopy, non-contact atomic force microscopy (nc-AFM), X-ray photoelectron spectroscopy and scanning tunneling microscopy (STM). The topographic corrugation of the MoS₂ monolayer on Au(111), revealed in a moiré structure, was measured as ≈20 pm by nc-AFM. The estimated defect density calculated from STM images of the as-grown MoS₂ monolayers is in the order of 10¹² vacancies/cm². The defects are mainly caused by single sulfur vacancies. Our approach is a step forward towards the technologically relevant growth of high-quality, large-area TMD monolayers.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432824001252/pdfft?md5=b776c9f2d037f2977249c2f723f48961&pid=1-s2.0-S0968432824001252-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes of epidermal proteins immunolocalization in the corneous layer from embryonic to definitive avian beak","authors":"","doi":"10.1016/j.micron.2024.103704","DOIUrl":"10.1016/j.micron.2024.103704","url":null,"abstract":"<div><p>The process of keratinization and cornification in the developing beak has been studied through immunofluorescence and immunogold electron microscopy in chick and zebrafinch embryos. After the curved beak anlagen appears at the tip of the maxillar bone, 5–8 layers of embryonic epidermis are generated from the basal layer of the epidermis. These cells are weakly immunoabeled for IFKs (Intermediate Filament Keratins) and more intensely for scaffoldin, a protein of the EDC (Epidermal Differentiation Complex) involved in the soft keratinization of the embryonic epidermis. Immunolabeling for CBPs (Corneous Beta Proteins) is visible in the transitional embryonic layers that are temporarily generated between the embryonic and definitive beak epidermis. The electron microscope reveals that intermediate layers contain immunolabeled periderm granules for scaffoldin mixed with bundles of corneous material immunolabeled for CBPs. Intense CBPs labeling occurs in the compacting corneous bundles of beta-keratinocytes in the definitive beak while scaffolding labeling disappears. The embryonic epidermis is sloughed before hatching. Sox (Sulfhydryl Oxidase) immunolabeling reveals that the enzyme is almost absent in embryonic layers but is present in transitional and definitive beta-keratinocytes. This indicates the formation of cross-linked disulfide bonds in the definitive corneous layer of the beak. Some calcium precipitation, suggested from von Kossa staining, occurs in the corneous layers only on the 18th day of development in the chick, in preparation for hatching.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration of the thickness-depended dynamic properties of differential phase contrast (DPC) and integrated differential phase contrast (iDPC)","authors":"","doi":"10.1016/j.micron.2024.103705","DOIUrl":"10.1016/j.micron.2024.103705","url":null,"abstract":"<div><p>A study on DPC and iDPC images of crystals is achieved with simulation. It highlights the use of electron wave intensity distribution to visualize the dynamic effect on DPC and iDPC contrasts. Electron waves near heavy atoms exhibit significant oscillations and rapid intensity decay. This oscillation causes DPC and iDPC signal inversion. Bloch wave theory is used to derive DPC and iDPC intensity distributions, elucidating the impact of dynamic effect on the contrast.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142058169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of extended defects in 2D materials using aperture-based dark-field STEM in SEM","authors":"","doi":"10.1016/j.micron.2024.103703","DOIUrl":"10.1016/j.micron.2024.103703","url":null,"abstract":"<div><p>Quantitative diffraction contrast analysis with defined diffraction vectors is a well-established method in TEM for studying defects in crystalline materials. A comparable transmission technique is however not available in the more widely used SEM platforms. In this work, we transfer the aperture-based dark-field imaging method from the TEM to the SEM, thus enabling quantitative diffraction contrast studies at lower voltages in SEM. This is achieved in STEM mode by inserting a custom-made aperture between the sample and the STEM detector and centering the hole on a desired reflection. To select individual reflections for dark-field imaging, we use our Low Energy Nanodiffraction (LEND) setup [Schweizer et al., Ultramicroscopy 213, 112956 (2020)], which captures transmission diffraction patterns from a fluorescent screen positioned below the sample. The aperture-based dark-field STEM method is particularly useful for studying extended defects in 2D materials, where (i) stronger diffraction at the lower voltages used in SEM is advantageous, but (ii) two-beam conditions cannot be established, making quantitative diffraction contrast analysis with standard bright-field and annular dark-field detectors impossible. We demonstrate the method by studying basal plane dislocations in bilayer graphene, which have attracted considerable research interest due to their exceptional structural and electronic properties. Direct comparison of results obtained on identical dislocations by the established TEM method and by the new aperture-based dark-field STEM method in SEM shows that a reliable Burgers vector analysis is possible by applying the well-known <strong>g</strong>·<strong>b</strong>=0 invisibility criterion. We further use the LEND setup to acquire 4D-STEM data and show that the virtual dark-field images match well with those in aperture-based dark-field STEM images for reliable Burgers vector analysis.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432824001203/pdfft?md5=64ab2493115192508e2fc931f59d243f&pid=1-s2.0-S0968432824001203-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142006976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deformation twinning and mechanical property of strongly textured titanium deformed at low temperatures","authors":"","doi":"10.1016/j.micron.2024.103702","DOIUrl":"10.1016/j.micron.2024.103702","url":null,"abstract":"<div><p>The exploration of deformation behaviors within titanium and its alloys across a spectrum of temperatures, in particular at the low temperature range, is imperative for the development of strong and tough titanium alloys. This study has been meticulously devised with an emphasis on the deformed microstructure and mechanical property of pure titanium at temperatures of 77 K, 180 K, 240 K, and 298 K. Tensile results indicate a concurrent enhancement in both strength and ductility, as well as the work hardening capacity, as the deformation temperature decreases. Quantitative analysis demonstrated such superior mechanical properties and hardening capacity are attributed to the high twin density and the predominant twin variations converting from {11−22} twins to {10−12} twins at low temperatures. Therefore, the present study potentially offers insights into the understanding and development of titanium alloys by facilitating the strategic manipulation of temperature-mediated twin activity.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141907049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Secondary growth ovarian follicles of the pigmented sterlet sturgeon Acipenser ruthenus L. 1758 (Acipenseriformes, Chondrostei, Actinopterygii, Osteichthyes) – Microscopic study of oocytes, egg envelope and diversification of follicular cells","authors":"","doi":"10.1016/j.micron.2024.103701","DOIUrl":"10.1016/j.micron.2024.103701","url":null,"abstract":"<div><p>The individual ovarian follicle of sturgeons (Acipenseriformes, Acipenseridae) contains an oocyte surrounded by follicular cells (FCs), basal lamina, and thecal cells. The late stages of the secondary growth of follicles (mid- and advanced vitellogenic) are not fully explained in Acipenseriformes. To explore and discuss the ultrastructure of oocytes, FCs, an egg envelope, and explain how micropylar cells differentiate and the canals of a multiple micropyle are formed, the samples of ovaries of the mature sterlet sturgeon <em>Acipenser ruthenus</em> were examined<em>.</em> The oocytes are polarized, the nucleus is located in the animal hemisphere, contains lampbrush chromosomes and multiple nucleoli. In the ooplasm three regions are present: a perinuclear (contains the mitochondria), an endoplasm (contains the lipid droplets and yolk platelets), and a periplasm (contains the cortical granules, melanosomes, endocytotic and exocytotic vesicles). The melanosomes in animal hemisphere form two concentric rings separated by a lighter region between them. The FCs are differentiated into bright and dark cells that are both translationally and secretory active. Diversification of FCs involves repeated and cytoskeleton-dependent change of shape. In the advanced follicles the FCs are diversified into micropylar, the animal and vegetal regions cells, and the cells that delaminated from the epithelium in the animal region. The egg envelope is present in the perioocytic space and consists of three layers: (1) an inner layer or vitelline envelope, (2) a middle layer, and (3) an outer layer. The inner layer consists of four sublayers: (a) a filamentous sublayer composed of filaments released from the oocytes, (b) a trabecular 1 sublayer and (c) a trabecular 2 sublayer named due to the sequence of the deposition, and composed of filaments, fibres and trabecules, (d) a homogeneous sublayer located between the trabecular 1 and trabecular 2 sublayers composed of filaments that adhere to each other closely. The middle layer contains two sublayers: a porous 1 and a porous 2 (composed of granular material) which are released by the oocyte and FCs. The outer layer consists of fibrillar material released by the FCs. The egg envelope is pierced by radial canals formed around the microvilli of the oocyte and the microvilli-like processes of FCs. A micropylar field in the egg envelope that covers the animal pole of the oocyte contains 1 – 4 micropylar canals. Micropylar cells are involved in their formation. The shape of these cells is icicle-like and the cytoplasm is differentiated into two regions (a basal and apical bearing a projection) equipped with different sets of organelles.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432824001185/pdfft?md5=672f91a3a80722ba79134182296a3a5c&pid=1-s2.0-S0968432824001185-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141917088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New insight in secretory structures and secretion composition in Rhus typhina L. – Anatomical, histochemical, and ultrastructural studies","authors":"","doi":"10.1016/j.micron.2024.103692","DOIUrl":"10.1016/j.micron.2024.103692","url":null,"abstract":"<div><p><em>Rhus typhina</em> is a valuable plant used in the pharmaceutical, cosmetic, and food industries due to the presence of biologically active substances accumulated in its organs, especially in secretory structures, i.e. trichomes and secretory ducts. Light microscopy, scanning electron microscopy, and transmission electron microscopy were used to examine the structure of glandular and non-glandular trichomes, as well as secretory ducts present in inflorescence peduncles <em>of R. typhina</em>. The chemical composition of the secretion produced by trichomes and ducts was assessed using histochemical techniques, including observations under brightfield and fluorescence microscopes. Two types of capitate glandular trichomes producing secretions with a similar composition and non-glandular trichomes exhibiting secretory activity were identified. The secretion of glandular trichomes was dominated by acidic and neutral lipids, essential oil, sesquiterpenes, and steroid-containing terpenes. The schizogenic secretory ducts located in the phloem produced a viscous milky substance with acidic polysaccharides, acidic lipids, phenolic compounds, and proteins. The secretion was released into the duct lumen through notches in the walls of the secretory epithelial cell facing the duct lumen. The location, type, and traits of the non-glandular trichomes and secretory structures, as well as the composition of the secreted products are considered important taxonomic features in the family Anacardiaceae and the <em>Rhus</em> genus. Additionally, these characters are important diagnostic markers for the pharmacobotanical identification of the species in medicinal and cosmetic raw materials. The various compounds present in the secretory structures of <em>R. typhina</em> may contribute to plant protection against pathogens or herbivory and probably play a role as attractants for pollinators and seed dispersers.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432824001094/pdfft?md5=a3c45a57e25dfd6af9bfe59e9083dec8&pid=1-s2.0-S0968432824001094-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141902294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological organisation of the digestive tract in the stream catfish Pseudecheneis sulcatus (McClelland)","authors":"","doi":"10.1016/j.micron.2024.103691","DOIUrl":"10.1016/j.micron.2024.103691","url":null,"abstract":"<div><p>We describe the histological organisation and mucin content in the digestive tract of the stream catfish <em>Pseudecheneis sulcatus</em>. The aim is to find the modifications of the digestive tract in relation to food resources of its habitat. The oesophageal mucosa consists of stratified squamous epithelium with many mucous-secreting cells. The thick muscularis contains an inner longitudinal and outer circular, striated muscle cells. The stomach is J-shaped and shows 6–7 thick mucosal folds that are separated from the submucosa by an organised muscularis mucosae. The mucosa consists of superficial cells with mucin granules, and deeper simple tubular gastric glands in cardia and fundus, but absent in pyloric region. The glandular epithelium shows oxynticopeptic cells containing zymogen granules and abundant tubulo-vesicular bodies. We provide evidence that the latter arise by budding from smooth endoplasmic reticulum and reach the apical cytoplasm. The anterior intestine shows longer mucosal folds with goblet cells (GC). GC are more in the posterior intestine and highest in the rectum. Myenteric neurons with myelinated and non-myelinated axons innervate the intrinsic musculature from stomach to rectum. Many stem cells are evident in the basal intestinal epithelium. They show darker nuclei and undifferentiated organelles. Mucin histochemistry reveals the predominance of neutral mucin (PAS⁺ positive) from oesophagus to rectum, and neutral and acidic mucin (alcian blue⁺, pH 2.5) in the posterior intestine to the rectum, with few GC colocalizing both. Ultrastructural features suggest that the species is adapted to omnivory and this is reflected in the predominance of neutral mucin in the digestive tract.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Carbon and Platinum Protective Layers on EDS Accuracy in FIB Cross-Sectional Analysis of W/Hf/W thin-film multilayers","authors":"","doi":"10.1016/j.micron.2024.103689","DOIUrl":"10.1016/j.micron.2024.103689","url":null,"abstract":"<div><p>Achieving high-quality cross sections is essential for accurate analysis of multilayer coatings. One method of performing such cross sections is focused ion beam, where sample protection from ion damage in the form of protective layers applied by FEBID and FIBID methods is used. Due to the lack of comparative summaries of different layers applied by these methods, especially in the context of cross-sectional analysis and elemental analysis of the cross-section, it was decided to address the effect of the protective layer on the reliability of EDS analysis. This study compares the effectiveness of platinum and carbon protective layers in creating cross sections for W/Hf/W samples. The effect of protective layers on elemental mapping and elemental analysis accuracy was evaluated. This study highlights the importance of protective layer selection in providing reliable EDS analysis of cross sections.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432824001069/pdfft?md5=2a4608209d401e80c1ae504c4604d7aa&pid=1-s2.0-S0968432824001069-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141689976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}