- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Evaluation of art subjects implemented in the marquetry technique by the optical coherence microscopy method
摘要： Evaluation of internal microstructure of decorative and applied art objects implemented in the intarsia and marquetry techniques by the optical coherence tomography method is considered. The high resolving optical coherence microscope with a radiation source with tunable wavelength in the range of 1305 ± 75 nm was applied. The ability to analyse layered microstructure of wood object surface layer in intarsia regions is demonstrated. The geometric features evaluation of the object's microstructure in the areas of interest was conducted. Systematisation of layers structure and typical defects inherent in intarsia regions was performed considering the structural features that may be important for restoration of such objects. Examples of experimentally obtained B‐scans and three‐dimensional representations of sample fragments of microstructure studied by the optical coherence microscopy method are given.
关键词： intarsia,optical coherence microscopy,incrustation,marquetry,3‐D imaging
更新于2025-09-23 15:22:29
-
Voids in Kesterites and the Influence of Lamellae Preparation by Focused Ion Beam for Transmission Electron Microscopy Analyses
摘要： Kesterite solar cells based on Cu2 ZnSnS4 and Cu2 ZnSnSe4 (CZTSe) are potential future candidates to be used in thin-film solar cells. The technology still has to be developed to a great extent and for this to happen, high levels of confidence in the characterization methods are required, so that improvements can be made on solid interpretations. In this study, we show that the interpretations of one of the most used characterization techniques in kesterites, scanning transmission electron microscopy (STEM), might be affected by its specimen preparation when using focused ion beam (FIB). Using complementary measurements based on scanning electron microscopy and Raman scattering spectroscopy, compelling evidence shows that secondary phases of ZnSe mixed in the bulk of CZTSe are the likely cause of the appearance of voids in STEM lamellae. Sputtering simulations support this interpretation by showing that Zn in a ZnSe matrix is preferentially sputtered compared with any metal atom in a CZTSe matrix.
关键词： Cu2 ZnSn(S, Se)4 (CZTSSe),thin-film solar cells,transmission electron microscopy (TEM),focused ion beam (FIB),kesterite
更新于2025-09-23 15:22:29
-
SMoLR: visualization and analysis of single-molecule localization microscopy data in R
摘要： Background: Single-molecule localization microscopy is a super-resolution microscopy technique that allows for nanoscale determination of the localization and organization of proteins in biological samples. For biological interpretation of the data it is essential to extract quantitative information from the super-resolution data sets. Due to the complexity and size of these data sets flexible and user-friendly software is required. Results: We developed SMoLR (Single Molecule Localization in R): a flexible framework that enables exploration and analysis of single-molecule localization data within the R programming environment. SMoLR is a package aimed at extracting, visualizing and analyzing quantitative information from localization data obtained by single-molecule microscopy. SMoLR is a platform not only to visualize nanoscale subcellular structures but additionally provides means to obtain statistical information about the distribution and localization of molecules within them. This can be done for individual images or SMoLR can be used to analyze a large set of super-resolution images at once. Additionally, we describe a method using SMoLR for image feature-based particle averaging, resulting in identification of common features among nanoscale structures. Conclusions: Embedded in the extensive R programming environment, SMoLR allows scientists to study the nanoscale organization of biomolecules in cells by extracting and visualizing quantitative information and hence provides insight in a wide-variety of different biological processes at the single-molecule level.
关键词： Image analysis,Image quantification,Super-resolution,Microscopy,R,Single-molecule localization
更新于2025-09-23 15:22:29
-
Reflectance confocal microscopy of cutaneous melanoma. Correlation with dermoscopy and histopathology
摘要： In vivo Confocal Microscopy is a method for non-invasive, real-time visualization of microscopic structures and cellular details of the epidermis and dermis, which has a degree of resolution similar to that obtained with histology. We present a case of cutaneous melanoma in which diagnosis was aided by confocal microscopy examination. We also correlate the observed features with the dermoscopic and histopathological findings. Confocal microscopy proved to be an useful adjunct to dermoscopy, playing an important role as a method 'between clinical evaluation and histopathology'.
关键词： Melanoma,Diagnosis,Dermoscopy,Confocal microscopy
更新于2025-09-23 15:22:29
-
An optimized harmonic probe with tailored resonant mode for multifrequency atomic force microscopy
摘要： For simultaneously measuring specimen’s surface morphology and material properties, multifrequency atomic force microscopy is often employed. In this kind of atomic force microscopy, if the probe’s higher-order resonance frequencies match the integer multiples of its fundamental frequency, the probe’s responses at such harmonic frequencies will be enhanced. Meanwhile, an enlarged effective slope during vibration at the probe’s tip results in an improved probe sensitivity. Moreover, increasing the probe’s natural frequency leads to a fast scanning speed. In this study, we propose to design cantilever probes that satisfy the aforementioned requirements via a structural optimization technique. A cantilever probe is represented by a three-layer symmetrical geometric model, and its width profile is continuously varied through the optimization procedure. Thereafter, an optimized design of probe considering the fifth harmonic is prepared by focused ion beam milling. Both simulation and experiment results show that the prepared probe agrees well with design requirements.
关键词： resonant frequency,tapping-mode,structural optimization,modal assurance criterion,Multifrequency atomic force microscopy
更新于2025-09-23 15:22:29
-
V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate
摘要： InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.
关键词： V defects,Transmission electron microscopy (TEM),InGaN multi-quantum well (MQW),Threading dislocations (TDs)
更新于2025-09-23 15:22:29
-
DNA origami deposition on native and passivated molybdenum disulfide substrates
摘要： Maintaining the structural fidelity of DNA origami structures on substrates is a prerequisite for the successful fabrication of hybrid DNA origami/semiconductor-based biomedical sensor devices. Molybdenum disulfide (MoS2) is an ideal substrate for such future sensors due to its exceptional electrical, mechanical and structural properties. In this work, we performed the first investigations into the interaction of DNA origami with the MoS2 surface. In contrast to the structure-preserving interaction of DNA origami with mica, another atomically flat surface, it was observed that DNA origami structures rapidly lose their structural integrity upon interaction with MoS2. In a further series of studies, pyrene and 1-pyrenemethylamine, were evaluated as surface modifications which might mitigate this effect. While both species were found to form adsorption layers on MoS2 via physisorption, 1-pyrenemethylamine serves as a better protective agent and preserves the structures for significantly longer times. These findings will be beneficial for the fabrication of future DNA origami/MoS2 hybrid electronic structures.
关键词： atomic force microscopy (AFM),molybdenum disulfide (MoS2),1-pyrenemethylamine,pyrene,DNA origami,surface modification
更新于2025-09-23 15:22:29
-
Transmission Electron Microscopy of Halide Perovskite Materials and Devices
摘要： Transmission electron microscopy (TEM)-based techniques are uniquely suited for site-specific structural and analytical characterization of halide perovskites (HPs) at atomic, nanometer, and micrometer length scales. TEM-based studies hold the key to understanding the nature and functionality of these fascinating materials that are at the heart of emerging solar cells and (opto)electronic devices. While TEM-based techniques have made several groundbreaking discoveries that have resulted in astonishing advancements in the field of materials science in general over the past decades, their application to HPs has been relatively sparse. Here, we provide a perspective on TEM-based studies of HPs that have been conducted so far and project a vision for how these powerful characterization techniques can be brought to bear on research problems in the field of HPs. An outlook discussing important challenges and opportunities that lay ahead is also presented.
关键词： Halide Perovskites,Optoelectronics,Materials Characterization,Solar Cells,Transmission Electron Microscopy
更新于2025-09-23 15:22:29
-
Photoacoustic microscopy reveals the hemodynamic basis of sphingosine 1-phosphate-induced neuroprotection against ischemic stroke
摘要： Rationale: Emerging evidence has suggested that sphingosine 1-phosphate (S1P), a bioactive metabolite of sphingolipids, may play an important role in the pathophysiological processes of cerebral hypoxia and ischemia. However, the influence of S1P on cerebral hemodynamics and metabolism remains unclear. Material and Methods: Uniquely capable of high-resolution, label-free, and comprehensive imaging of hemodynamics and oxygen metabolism in the mouse brain without the influence of general anesthesia, our newly developed head-restrained multi-parametric photoacoustic microscopy (PAM) is well suited for this mechanistic study. Here, combining the cutting-edge PAM and a selective inhibitor of sphingosine kinase 2 (SphK2) that can increase the blood S1P level, we investigated the role of S1P in cerebral oxygen supply-demand and its neuroprotective effects on global brain hypoxia induced by nitrogen gas inhalation and focal brain ischemia induced by transient middle cerebral artery occlusion (tMCAO). Results: Inhibition of SphK2, which increased the blood S1P, resulted in the elevation of both arterial and venous sO2 in the hypoxic mouse brain, while the cerebral blood flow remained unchanged. As a result, it gradually and significantly reduced the metabolic rate of oxygen. Furthermore, pre-treatment of the mice subject to tMCAO with the SphK2 inhibitor led to decreased infarct volume, improved motor function, and reduced neurological deficit, compared to the control treatment with a less potent R-enantiomer. In contrast, post-treatment with the inhibitor showed no improvement in the stroke outcomes. The failure for the post-treatment to induce neuroprotection was likely due to the relatively slow hemodynamic responses to the SphK2 inhibitor-evoked S1P intervention, which did not take effect before the brain injury was induced. Conclusions: Our results reveal that elevated blood S1P significantly changes cerebral hemodynamics and oxygen metabolism under hypoxia but not normoxia. The improved blood oxygenation and reduced oxygen demand in the hypoxic brain may underlie the neuroprotective effect of S1P against ischemic stroke.
关键词： Sphingosine 1-phosphate,Photoacoustic microscopy,Neuroprotection,Hypoxia,Ischemic stroke
更新于2025-09-23 15:22:29
-
European Microscopy Congress 2016: Proceedings || Fivefold symmetries in silicon thin films induced by multiple twinning
摘要： Fivefold symmetry, like any kind of n-fold rotational symmetry, can be identifiable when rotating a crystalline configuration 5 times (or n times) around a certain axis and realizing that the structure is transformed into a configuration that is equivalent to the initial one. The occurrence of this specific symmetry, forbidden by the conventional periodic crystallography, was attributed in the literature to the presence of a new state of matter 'the quasicrystals' [1] [2] or simply to an effect of multiple twinning. Particularly, the tendency of multiply twinning in a fivefold symmetry has been widely reported in small particles having a special morphology like the decahedral [3] or icosahedral [4] structures, usually called multiply twinned particles. In this study, we will highlight on the fivefold symmetry observed in the electron diffraction patterns of two types of materials elaborated in different growth conditions, originating from multiple twinning and not from the presence of multiply twinned particles. The first case concerns the fivefold symmetry on p-type doped silicon thin films containing a non-negligible amount of carbon and oxygen. These films were deposited in a plasma enhanced chemical vapor deposition reactor (PECVD) at 0.2 W/cm2 using silane, hydrogen, diborane and hexamethydisiloxane (C6H18OSi2, HMDSO) diluted in argon. Since all the diffraction patterns recorded on different regions of these films exhibit a fivefold symmetry along [0-11] zone axis (Figure 1), it is clear that this symmetry is real and characteristic of our films. Further diffraction measurements reveal that there is a relation of epitaxy with the (100) crystalline silicon substrate. This is also confirmed by high resolution TEM images, where {111} planes are continuing from the substrate to the film across the interface. Moreover, energy filtered TEM images were correlated with SIMS measurements to provide elemental mapping of silicon, carbon and oxygen with absolute values. The second case illustrates a quasi-fivefold symmetry recorded on intrinsic silicon thin films deposited by PECVD using silicon tetrafluoride, hydrogen and argon chemistry at a purposely high power density of 0.3 W/cm2. After few hundred nanometers of epitaxial growth, a high density of defects appears, followed by a multiply twinned part (as shown in Figure 2a). Fourier Transforms recorded on the first part reveal a monocrystalline structure (Figure 2c), and on the second part a fivefold symmetry (Figure 2b), which is, in this case also, linked to an epitaxial growth. It has been proved in some references [5] [6] that a high power density is responsible for a high ion energy impinging on the substrate and causing some surface or even bulk damage. Thus, the twin defects present in our films are most probably caused by the application of a high power density. However, to obtain a fivefold symmetry, it is necessary to have at least three orders of twinning that contribute to 10 spots in the diffraction pattern, i.e, if there only exist two orders of twinning, some additional diffraction spots appear without giving rise to a fivefold symmetry as it is the case of Figure 3. Detailed investigation of the multiple twinning in a fivefold symmetry fashion will be presented.
关键词： silicon,Transmission electron microscopy,epitaxy,twin,fivefold symmetry
更新于2025-09-23 15:22:29