Geometrical calculation and drawing of electron diffraction patterns using computers are described according to the reciprocal lattice, Ewald construction and extinction rule. Reciprocal lattice points with the excitation error less than a set value are plotted, including those in high-order Laue zones. A procedure to determine the incident beam direction and indices of the reflections for experimental diffraction patterns is also introduced. The distances between three reflections in the zero-order Laue zone are used to find the candidates of the indices for the reflections and they were examined by the comparison between the experimental and calculated diffraction patterns.
Both (Conventional) Transmission Electron Microscopy (CTEM) and Scanning Transmission Electron Microscopy (STEM) give atomic resolution images under optimum conditions. However, in order to confirm the proposed structure based on the micrographs we need image simulation. Image simulation program will give some images, when we provide sample information and imaging conditions. However, CTEM and STEM images are generated from different signals, and the effect of the objective lens differs between two imaging modes. Thus, in order to evaluate the simulated images we have to understand the fundamental ideas as well as basic concepts of image simulation. In this article, I will explain, based on the multislice method, the fundamentals of high-resolution image simulation, especially the techniques to estimate elastic and thermal diffuse scattering and to handle partial coherence.
First principles calculation gives us fruitful information such as formation energy, atomic structure, and chemical bonding. Thus the combination of the first principles calculation and electron microscopy techniques is indispensable in the field of material science. Here, we are describing the basics of the first principles calculation and its application to EELS.
Multivariate statistical analysis (MSA) is one of essential approaches to effectively analyze large scale spectrum imaging (SI) datasets, which can be acquired in modern analytical electron microscopes (AEMs). In this article, first, principles and advantages of the MSA approaches based on the most popular principal component analysis (PCA) will be explained with several applications. Then, some issues/artifacts that might be introduced by applying the PCA method are also addressed. Finally, the recently developed LocalPCA method is also introduced，which has been developed by the authors to overcome some of artifacts introduced by the PCA.
Graphene is an ideal two dimensional atomic layer, and has been energetically investigated due to its superior electronic properties for high-speed electronic device applications. In this report, focusing on the SiC surface thermal decomposition method, one of the synthetic methods, the growth mechanism, interface structures between graphene and substrate, and the stacking sequence of epitaxial graphene obtained by observation mainly with transmission electron microscopy were interpreted. In particular, the variety and advantages of influence of polarity or surface step-terrace structure of SiC were introduced, and the topics about peculiar electronic properties, crystallographic anisotropy, nano-ribboned structure, and twisted-stacked structure were reviewed, and then its possibility was discussed.
For unraveling original roles of the gene, it is important to determine the regulation at the transcriptional or translational level, the degradation rate and intracellular localization in the individual cells while considering the expression kinetics of both mRNA and protein. In situ hybridization and immunohistochemistry are used to detect the expression and localization of the specific sequence of nucleic acid or protein in tissue sections, respectively. In this review, focusing on in situ hybridization method, we described the necessity and the basic principle of visualization of mRNA, and introduced the methods for evaluation and analysis, and finally explained the application example.
Olfactory bulb (OB) is an attractive region for analyzing neural circuit in the brain. It has been so far well-examined by many researchers with special focus on interneurons in the OB. Recent progress in neuronal labeling and biological application by newly developed microscopes enable to reveal long-distance projection neuron from other brain regions to the OB as centrifugal input, which have not been analyzed for overall morphology becoming structural basis for understanding regulatory function to the OB neural circuit. By using combination of transgenic mice, genetic induction by viral vectors, multiple immuno-labeling, correlative laser and electron microscopies, digital tracing of a single neuron, and electron tomography, we have been analyzing centrifugal regulation to the OB neural circuit. In the review, we show our current and recent findings for serotonin neurons to the OB and discuss significance of presence of regulatory inputs to the OB from other brain regions. We further propose some possibilities in future analyses to be structural basis for neural circuit functions.
In recent research in bioimaging, quantitative treatment of biological morphological information captured by microscopy is very important for objective understanding of biological phenomena. This paper deals with essential methods of digital image processing and analysis for quantification of the biological information. Especially, causes of digital error and measurement error which occur during the process of image measurement are discussed.
In recent years SEM-EDS has become a very friendly and useful surface analysis device by its technological innovation, but it is thought that EPMA (here, this word means “Electron probe microanalyzer with WDS” contrasted with SEM-EDS) which has low minimum detection limit and superior quantitative precision will continue to be used as the surface analysis device which is indispensable in solving problems in various fields. Particularly in late years the space resolving power of the element mapping image was remarkably improved by appearance of the EPMA with FE electron gun (FE-EPMA), so the application range of EPMA is rather spreading. In order to deepen understanding about EPMA, this lecture gives brief explanation about the difference between EPMA and SEM-EDS first, then describes characteristic performance and function of EPMA and shows one of applications with latest FE-EPMA.
A novel Zeff imaging using X-ray interferometer has been developed. Since the effective atomic number (Zeff) corresponds to the ratio of the real to imaginary part of the complex refractive index, an elemental map is calculable with the ratio of an absorption and phase-contrast image. Several metal foils underwent feasibility observations by crystal X-ray interferometry. The obtained Zeff image shows that aluminum, iron, nickel, and copper foil were clearly distinguished, and nickel and copper’s Zeff values coincide with ideal Z number within 5%.
The Cc corrector was developed by applying a combination concave-lens effect from a thick twofold astigmatism field. Magnetic and electrostatic twofold astigmatism fields produced by dodecapoles were used to introduce the concave lens effect. The Cc corrector was mounted below the objective lens, and the Delta-type corrector for a TEM was also installed below the Cc corrector in tandem to correct geometrical aberrations. The simultaneous Cc and Cs correction and atomic-resolution imaging on a TEM using the system were experimentally demonstrated at an accelerating voltage of 30 kV.