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2022 ◽  
Vol 12 (2) ◽  
pp. 882
Author(s):  
Yu-Lin Song ◽  
Manoj Kumar Reddy ◽  
Hung-Yung Wen ◽  
Luh-Maan Chang

The extremely low-frequency (ELF) and its corresponding electromagnetic field influences the yield of CMOS processes in the foundry, especially for high-end equipment such as scanning electron microscopy (SEM) systems, transmission electron microscopy (TEM) systems, focused ion beam (FIB) systems, and electron beam lithography (E-Beam) systems. There are several techniques to mitigate electromagnetic interference (EMI), among which active shielding systems and passive shielding methods are widely used. An active shielding system is used to generate an internal electromagnetic field to reduce the detected external electromagnetic field in electric coils with the help of the current. Although the active shielding system reduces the EMI impact, it induces an internal electromagnetic field that could affect the function of nearby tools and/or high-performance probes. Therefore, in this study, we have used a C-shaped cylindrical device combined with an active shielding system and passive shielding techniques to reduce EMI for online monitoring and to overcome the aforementioned issues. In this study, the active shielding system was wrapped with a permalloy composite material (i.e., a composite of nickel and iron alloy) as a tubular device. A C-shaped opening was made on the tubular structure vertically or horizontally to guide the propagation of the electromagnetic field. This C-shaped cylindrical device further reduced electromagnetic noise up to −5.06 dB and redirected the electromagnetic field toward the opening direction on the cylindrical device. The results demonstrated a practical reduction of the electromagnetic field.


Author(s):  
Alraune Zech ◽  
Matthijs de Winter

AbstractWe investigate the upscaling of diffusive transport parameters using a stochastic framework. At sub-REV (representative elementary volume) scale, the complexity of the pore space geometry leads to a significant scatter of the observed diffusive transport. We study a large set of volumes reconstructed from focused ion beam-scanning electron microscopy data. Each individual volume provides us sub-REV measurements on porosity and the so-called transport-ability, being a dimensionless parameter representing the ratio of diffusive flux through the porous volume to that through an empty volume. The detected scatter of the transport-ability is mathematically characterized through a probability distribution function (PDF) with a mean and variance as function of porosity, which includes implicitly the effect of pore structure differences among sub-REV volumes. We then investigate domain size effects and predict when REV scale is reached. While the scatter in porosity observations decreases linearly with increasing sample size as expected, the observed scatter in transport-ability does not converge to zero. Our results confirm that differences in pore structure impact transport parameters at all scales. Consequently, the use of PDFs to describe the relationship of effective transport coefficients to porosity is advantageous to deterministic semiempirical functions. We discuss the consequences and advocate the use of PDFs for effective parameters in both continuum equations and data interpretation of experimental or computational work. The presented statistics-based upscaling technique of sub-REV microscopy data provides a new tool in understanding, describing and predicting macroscopic transport behavior of microporous media.


2022 ◽  
pp. 1-10
Author(s):  
Dong Hyun Kim ◽  
Eun-Mi Kim ◽  
Gi-Seok Heo ◽  
Dong Wook Lee ◽  
Jin Young Oh ◽  
...  

Author(s):  
Osamu Ueda ◽  
Makoto Kasu ◽  
Hirotaka Yamaguchi

Abstract This paper reviews the status of characterization of defects in β-Ga2O3 crystals grown by edge-defined film-fed growth and hydride vapor phase epitaxy using chemical etching, scanning electron microscopy, focused ion beam scanning ion microscopy, X-ray topography (XRT), and transmission electron microscopy (TEM). The observed defects are classified into four types: dislocations, stacking faults (SFs), twins, and plate-like nanovoids (PNVs). First, we present the detailed characterization of dislocations in the crystal by chemical etching, XRT, and TEM, and discuss possible slip systems. Next, we describe XRT analyses of two types of SFs: SFs 1 lying on the (2 ̅01) plane and SFs 2 on the (111) and (11 ̅1) planes. We describe the results for twins found in crystals via high-resolution TEM and electron diffraction analysis, and PNVs corresponding to etch pits on the (010) plane. Finally, we discuss possible generation mechanisms of the defects and their influence on device characteristics.


2022 ◽  
Vol 1 (1) ◽  
pp. 30
Author(s):  
Po-Kai Chiu ◽  
Donyau Chiang ◽  
Chien-Nan Hsiao ◽  
Fong Zhi Chen

2022 ◽  
Author(s):  
Dongye Zhao ◽  
Sebastijan Brezinsek ◽  
Rongxing Yi ◽  
Jannis Oelmann ◽  
Cai Laizhong ◽  
...  

Abstract One set of horizontal target elements of the Test Divertor Units (TDU), retrieved from the Wendelstein 7-X (W7-X) vessel after the end of second divertor Operation Phase (OP1.2B) in Hydrogen (H), were investigated by picosecond Laser-Induced Breakdown Spectroscopy (ps-LIBS). The Boron (B) distribution, H pattern and the material erosion/deposition pattern on these target elements were analyzed with high depth resolution and mapped in the poloidal direction of W7-X. From the spectroscopic analysis, B, H, Carbon (C) and Molybdenum (Mo) were clearly identified. A non-uniformly distributed B pattern on these divertor target elements was determined by the combination of B layer deposition during the three boronizations and W7-X plasma operation with multiple erosion and deposition steps of B. Like the TDU, the analyzed target elements are made of fine grain graphite, but have two marker layers which allow us to determine the material migration via the ps-LIBS technique. Two net erosion zones including one main erosion zone with a peak erosion depth of 6.5 μm and one weak erosion with a peak erosion of 1.3 μm were determined. Between two net erosion zones, a net deposition zone with width of 135 mm and a thickness up to 3.5 μm at the peak deposition location was determined by the ps-LIBS technique. The B distributions are correlated with the erosion/deposition pattern and the operational time in standard magnetic configuration of W7-X in the phases after the boronizations. The thickness of the containing B layer on these target elements also correlates with the erosion/deposition depth, in which the thickness of the containing B layer varies spatially in poloidal direction between 0.1 μm and 6 μm. Complementary, Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) was employed also to verify and investigate the deposition layer thicknesses at typical net erosion and net deposition zones as well as to identify the three boronizations in depth.


2022 ◽  
Vol 9 (1) ◽  
pp. 30
Author(s):  
Alessio Zanza ◽  
Marco Seracchiani ◽  
Rodolfo Reda ◽  
Gabriele Miccoli ◽  
Luca Testarelli ◽  
...  

Since there are no reviews of the literature on this theme, the aim of this narrative review is to summarize the metallurgical tests used in endodontics, pointing out their functional use and their pros and cons and giving readers a user-friendly guide to serve as an orientation aid in the plethora of metallurgical tests. With this purpose, a literature search for articles published between January 2001 and December 2021 was conducted, using the electronic database PubMed to collect all published articles regarding the metallurgical tests used in endodontics for the evaluation of NiTi rotary instruments. The search was conducted using the following keywords: “metallurgy”, “differential scanning calorimetry” (DSC), “X-ray diffraction” (XRD), “atomic force microscopy” (AFM), “energy-dispersive X-ray spectroscopy” (EDS), “focused ion beam analysis” (FIB) and “Auger electron spectroscopy” (AES) combined with the term “endodontics” or “NiTi rotary instruments”. Considering the inclusion and exclusion criteria, of the 248 articles found, only 81 were included in the narrative review. According to the results, more than 50% of the selected articles were published in one of the two most relevant journals in endodontics: International Endodontic Journal (22.2%) and Journal of Endodontics (29.6%). The most popular metallurgical test was DSC, with 43 related articles, followed by EDS (33 articles), AFM (22 articles) and XRD (21 articles). Few studies were conducted using other tests such as FIB (2 articles), micro-Raman spectroscopy (4 articles), metallographic analysis (7 articles) and Auger electron spectroscopy (2 articles).


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Rui Yang ◽  
Ichiro Ogura ◽  
ZhenYan Jiang ◽  
LinJun An ◽  
Kiwamu Ashida ◽  
...  

AbstractThe application of self-excitation is proposed to improve the efficiency of the nanoscale cutting procedure based on use of a microcantilever in atomic force microscopy. The microcantilever shape is redesigned so that it can be used to produce vibration amplitudes with sufficient magnitudes to enable the excitation force applied by an actuator to be transferred efficiently to the tip of the microcantilever for the cutting process. A diamond abrasive that is set on the tip is also fabricated using a focused ion beam technique to improve the cutting effect. The natural frequency of the microcantilever is modulated based on the pressing load. Under conventional external excitation conditions, to maintain the microcantilever in its resonant state, it is necessary to vary the excitation frequency in accordance with the modulation. In this study, rather than using external excitation, the self-excitation cutting method is proposed to overcome this difficulty. The self-excited oscillation is produced by appropriate setting of the phase difference between the deflection signal of the microcantilever and the feedback signal for the actuator. In addition, it is demonstrated experimentally that the change in the phase difference enables us to control the amplitude of the self-excitation. As a result, control of the cutting depth is achieved via changes in the phase difference.


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