Quantitative analysis of retained austenite in Nb added Fe-based alloySpringer Science and Business Media LLC - Tập 52 - Trang 1-10 - 2022
Kwang Kyu Ko, Jin Ho Jang, Saurabh Tiwari, Hyo Ju Bae, Hyo Kyung Sung, Jung Gi Kim, Jae Bok Seol
The use of Pipelines for long-distance transportation of crude oil, natural gas and similar applications is increasing and has pivotal importance in recent times. High specific strength plays a crucial role in improving transport efficiency through increased pressure and improved laying efficiency through reduced diameter and weight of line pipes. TRIP-based high-strength and high-ductility alloys comprise a mixture of ferrite, bainite, and retained austenite that provide excellent mechanical properties such as dimensional stability, fatigue strength, and impact toughness. This study performs microstructure analysis using both Nital etching and LePera etching methods. At the time of Nital etching, it is difficult to distinctly observe second phase. However, using LePera etching conditions it is possible to distinctly measure the M/A phase and ferrite matrix. The fraction measurement was done using OM and SEM images which give similar results for the average volume fraction of the phases. Although it is possible to distinguish the M/A phase from the SEM image of the sample subjected to LePera etching. However, using Nital etching is nearly impossible. Nital etching is good at specific phase analysis than LePera etching when using SEM images.
Electron beam irradiation induced crystallization behavior of amorphous Ge2Sb2Te5 chalcogenide materialSpringer Science and Business Media LLC - Tập 49 - Trang 1-2 - 2019
Byeong-Seon An
The crystallization of amorphous Ge2Sb2Te5 phase change material induced by electron beam irradiation was investigated by in-situ transmission electron microscopy (TEM). Amorphous matrix transformed into a partially crystalline state after being irradiated with a 200-keV electron beam for a long time. Real-time observation revealed that the crystallization of amorphous Ge2Sb2Te5 film occurs through a nucleation and growth mechanism under electron beam irradiation in TEM. While uncertainty from the 2D projection remains, the nuclei have been observed to grow preferentially along the < 100> direction.
Ultrastructure of the fertilized egg envelope from Melanotaenia praecox, Melanotaeniidae, TeleosteiSpringer Science and Business Media LLC - Tập 51 Số 1 - 2021
Joon Hyung Sohn, Dong Heui Kim
AbstractWe examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of dwarf rainbowfish (Melanotaenia praecox) belong to Melanotaeniidae using light and electron microscopes. The fertilized eggs were spherical with adhesive filament, transparent, demersal, and had a narrow perivitelline space and small oil droplets. The size of fertilized egg was 1.02 ± 0.18 mm (n = 30), and there were two kinds of adhesive filament on the fertilized eggs. The long and thick (diameter 12.22 ± 0.52 μm, n = 20) adhesive filaments were only at the area of animal pole, and short and thin (diameter 1.99 ± 0.23 μm, n = 20) adhesive filaments were around the long filaments. A micropyle was conical shaped with adhesive filament and located near the animal pole of egg. The outer surface of fertilized egg was rough side. Also, the total thickness of the fertilized egg envelope was about 7.46 ± 0.41 μm (n = 20), the fertilized egg envelope consisted of two layers, an inner lamellae layer and an outer layer with high electron-density. And the inner layer was 8 layers. Collectively, these morphological characteristics and adhesive property of fertilized egg with adhesive filaments, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.
Advanced atomic force microscopy-based techniques for nanoscale characterization of switching devices for emerging neuromorphic applicationsSpringer Science and Business Media LLC - Tập 51 - Trang 1-9 - 2021
Young-Min Kim, Jihye Lee, Deok-Jin Jeon, Si-Eun Oh, Jong-Souk Yeo
Neuromorphic systems require integrated structures with high-density memory and selector devices to avoid interference and recognition errors between neighboring memory cells. To improve the performance of a selector device, it is important to understand the characteristics of the switching process. As changes by switching cycle occur at local nanoscale areas, a high-resolution analysis method is needed to investigate this phenomenon. Atomic force microscopy (AFM) is used to analyze the local changes because it offers nanoscale detection with high-resolution capabilities. This review introduces various types of AFM such as conductive AFM (C-AFM), electrostatic force microscopy (EFM), and Kelvin probe force microscopy (KPFM) to study switching behaviors.
TEM sample preparation of microsized LiMn2O4 powder using an ion slicerSpringer Science and Business Media LLC - Tập 51 - Trang 1-7 - 2021
Jung Sik Park, Yoon-Jung Kang, Sun Eui Choi, Yong Nam Jo
The main purpose of this paper is the preparation of transmission electron microscopy (TEM) samples from the microsized powders of lithium-ion secondary batteries. To avoid artefacts during TEM sample preparation, the use of ion slicer milling for thinning and maintaining the intrinsic structure is described. Argon-ion milling techniques have been widely examined to make optimal specimens, thereby making TEM analysis more reliable. In the past few years, the correction of spherical aberration (Cs) in scanning transmission electron microscopy (STEM) has been developing rapidly, which results in direct observation at an atomic level resolution not only at a high acceleration voltage but also at a deaccelerated voltage. In particular, low-kV application has markedly increased, which requires a sufficiently transparent specimen without structural distortion during the sample preparation process. In this study, sample preparation for high-resolution STEM observation is accomplished, and investigations on the crystal integrity are carried out by Cs-corrected STEM.
Chất liệu thăng hoa hỗ trợ việc chuẩn bị mẫu TEM cho các vật liệu nano tan trong dầu Dịch bởi AI Springer Science and Business Media LLC - - 2020
Yingping Deng
Tóm tắtViệc chuẩn bị mẫu là rất quan trọng để xác định vật liệu nano bằng kính hiển vi điện tử truyền qua độ phân giải cao (HRTEM). Tuy nhiên, nhiều dung môi hữu cơ thông thường có thể hòa tan lớp hỗ trợ polymer hữu cơ cần thiết trong lưới TEM, điều này làm cho việc thu được mẫu chất lượng cao của các vật liệu nano tan trong dầu trở nên khó khăn. Trong nghiên cứu này, một phương pháp chuẩn bị mẫu mới cho các vật liệu nano tan trong dầu đã được phát triển bằng cách sử dụng vật liệu thăng hoa làm lớp chuyển tiếp. Các thí nghiệm cũng cho thấy không có thiệt hại nào xảy ra đối với lưới TEM và hình ảnh HRTEM chất lượng cao có thể được thu nhận thông qua phương pháp này. Cách tiếp cận này mở đường cho việc chuẩn bị mẫu HRTEM áp dụng cho các vật liệu nano tan trong dầu.
#chuẩn bị mẫu #vật liệu nano #kính hiển vi điện tử truyền qua #thăng hoa #vật liệu tan trong dầu
Methods of measuring presynaptic function with fluorescence probesSpringer Science and Business Media LLC - Tập 51 - Trang 1-7 - 2021
Yeseul Jang, Sung Rae Kim, Sung Hoon Lee
Synaptic vesicles, which are endogenous to neurotransmitters, are involved in exocytosis by active potentials and release neurotransmitters. Synaptic vesicles used in neurotransmitter release are reused via endocytosis to maintain a pool of synaptic vesicles. Synaptic vesicles show different types of exo- and endocytosis depending on animal species, type of nerve cell, and electrical activity. To accurately understand the dynamics of synaptic vesicles, direct observation of synaptic vesicles is required; however, it was difficult to observe synaptic vesicles of size 40–50 nm in living neurons. The exo-and endocytosis of synaptic vesicles was confirmed by labeling the vesicles with a fluorescent agent and measuring the changes in fluorescence intensity. To date, various methods of labeling synaptic vesicles have been proposed, and each method has its own characteristics, strength, and drawbacks. In this study, we introduce methods that can measure presynaptic activity and describe the characteristics of each technique.
One-step synthesis of Pt/a-CoOx core/shell nanocompositesSpringer Science and Business Media LLC - Tập 49 - Trang 1-5 - 2019
Daewoon Kim, Sung Joo Kim, Jong Min Yuk
Herein, we synthesize a core/shell Pt/a-CoOx nanocomposite via one-step synthesis using a strong reaction agent of borane t-butylamine(BBA) at 200 °C. Transmission electron microscopy study shows that the morphology of nanocomposites is controlled by the stirring time and perfect core/shell structure is formed with over 7 days stirring time.
Automated 3D scoring of fluorescence in situ hybridization (FISH) using a confocal whole slide imaging scannerSpringer Science and Business Media LLC - Tập 51 - Trang 1-12 - 2021
Ziv Frankenstein, Naohiro Uraoka, Umut Aypar, Ruth Aryeequaye, Mamta Rao, Meera Hameed, Yanming Zhang, Yukako Yagi
Fluorescence in situ hybridization (FISH) is a technique to visualize specific DNA/RNA sequences within the cell nuclei and provide the presence, location and structural integrity of genes on chromosomes. A confocal Whole Slide Imaging (WSI) scanner technology has superior depth resolution compared to wide-field fluorescence imaging. Confocal WSI has the ability to perform serial optical sections with specimen imaging, which is critical for 3D tissue reconstruction for volumetric spatial analysis. The standard clinical manual scoring for FISH is labor-intensive, time-consuming and subjective. Application of multi-gene FISH analysis alongside 3D imaging, significantly increase the level of complexity required for an accurate 3D analysis. Therefore, the purpose of this study is to establish automated 3D FISH scoring for z-stack images from confocal WSI scanner. The algorithm and the application we developed, SHIMARIS PAFQ, successfully employs 3D calculations for clear individual cell nuclei segmentation, gene signals detection and distribution of break-apart probes signal patterns, including standard break-apart, and variant patterns due to truncation, and deletion, etc. The analysis was accurate and precise when compared with ground truth clinical manual counting and scoring reported in ten lymphoma and solid tumors cases. The algorithm and the application we developed, SHIMARIS PAFQ, is objective and more efficient than the conventional procedure. It enables the automated counting of more nuclei, precisely detecting additional abnormal signal variations in nuclei patterns and analyzes gigabyte multi-layer stacking imaging data of tissue samples from patients. Currently, we are developing a deep learning algorithm for automated tumor area detection to be integrated with SHIMARIS PAFQ.
Noise reduction of electron holography observations for a thin-foiled Nd-Fe-B specimen using the wavelet hidden Markov modelSpringer Science and Business Media LLC - Tập 54 Số 1
Su-Jin Lee, Yoshihiro Midoh, Yoshifumi Tomita, Takehiro Tamaoka, Mitsunari Auchi, Taisuke Sasaki, Yasukazu Murakami
AbstractIn this study, we investigate the effectiveness of noise reduction in electron holography, based on the wavelet hidden Markov model (WHMM), which allows the reasonable separation of weak signals from noise. Electron holography observations from a Nd2Fe14B thin foil showed that the noise reduction method suppressed artificial phase discontinuities generated by phase retrieval. From the peak signal-to-noise ratio, it was seen that the impact of denoising was significant for observations with a narrow spacing of interference fringes, which is a key parameter for the spatial resolution of electron holography. These results provide essential information for improving the precision of electron holography studies.
