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Micromachines
Volume 13
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Micromachines, Volume 13, Issue 10 (October 2022) – 244 articles

Cover Story (view full-size image): A novel core–shell dual-gate nanowire-structure-based single-transistor neuron with excitatory–inhibitory switching, threshold voltage tuning, and myelination functions was realized. This multi-functional neuron device can contribute to the construction of high-density monolithic SNN hardware combined with the vertical synapse MOSFET devices. View this paper
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14 pages, 6094 KiB  
Article
Thermo-Mechanical Reliability Study of Through Glass Vias in 3D Interconnection
by Jin Zhao, Zuohuan Chen, Fei Qin and Daquan Yu
Micromachines 2022, 13(10), 1799; https://doi.org/10.3390/mi13101799 - 21 Oct 2022
Cited by 12 | Viewed by 6201
Abstract
Three-dimensional (3D) interconnection technology based on glass through vias (TGVs) has been used to integrate passive devices, and optoelectronic devices due to its superior electrical qualities, outstanding mechanical stability, and lower cost. Nevertheless, the performance and reliability of the device will be impacted [...] Read more.
Three-dimensional (3D) interconnection technology based on glass through vias (TGVs) has been used to integrate passive devices, and optoelectronic devices due to its superior electrical qualities, outstanding mechanical stability, and lower cost. Nevertheless, the performance and reliability of the device will be impacted by the thermal stress brought on by the mismatch of the coefficient of thermal expansion among multi-material structures and the complicated structure of TGV. This paper focuses on thermal stress evolution in different geometric and material parameters and the development of a controlled method for filling polymers in TGV interconnected structures. In addition, a numerical study based on the finite element (FE) model has been conducted to analyze the stress distribution of the different thicknesses of TGV-Cu. Additionally, a TGV interconnected structure model with a polymer buffer layer is given to solve the crack problem appearing at the edge of RDL. Meanwhile, after practical verification, in comparison to the experimental results, the FE model was shown to be highly effective and accurate for predicting the evolution of stress, and several recommendations were made to alleviate stress-related reliability concerns. An improved manufacturing process flow for the TGV interconnected structure was proposed and verified as feasible to address the RDL crack issue based on the aforementioned research. It provides helpful information for the creation of highly reliable TGV connection structures. Full article
(This article belongs to the Special Issue Advanced Packaging for Microsystem Applications)
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13 pages, 2250 KiB  
Article
Electrochemical Testing of a New Polyimide Thin Film Electrode for Stimulation, Recording, and Monitoring of Brain Activity
by Samuel Ong, Aura Kullmann, Steve Mertens, Dave Rosa and Camilo A Diaz-Botia
Micromachines 2022, 13(10), 1798; https://doi.org/10.3390/mi13101798 - 21 Oct 2022
Cited by 2 | Viewed by 2134
Abstract
Subdural electrode arrays are used for monitoring cortical activity and functional brain mapping in patients with seizures. Until recently, the only commercially available arrays were silicone-based, whose thickness and lack of conformability could impact their performance. We designed, characterized, manufactured, and obtained FDA [...] Read more.
Subdural electrode arrays are used for monitoring cortical activity and functional brain mapping in patients with seizures. Until recently, the only commercially available arrays were silicone-based, whose thickness and lack of conformability could impact their performance. We designed, characterized, manufactured, and obtained FDA clearance for 29-day clinical use (510(k) K192764) of a new thin-film polyimide-based electrode array. This study describes the electrochemical characterization undertaken to evaluate the quality and reliability of electrical signal recordings and stimulation of these new arrays. Two testing paradigms were performed: a short-term active soak with electrical stimulation and a 29-day passive soak. Before and after each testing paradigm, the arrays were evaluated for their electrical performance using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) and Voltage Transients (VT). In all tests, the impedance remained within an acceptable range across all frequencies. The different CV curves showed no significant changes in shape or area, which is indicative of stable electrode material. The electrode polarization remained within appropriate limits to avoid hydrolysis. Full article
(This article belongs to the Special Issue Progress and Challenges of Implantable Neural Interfaces)
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7 pages, 1647 KiB  
Article
Suppression of the Electrical Crosstalk of Planar-Type High-Density InGaAs Detectors with a Guard Hole
by Jiaxin Zhang, Wei Wang, Haifeng Ye, Runyu Huang, Zepeng Hou, Chen Liu, Weilin Zhao, Yunxue Li, Xu Ma and Yanli Shi
Micromachines 2022, 13(10), 1797; https://doi.org/10.3390/mi13101797 - 21 Oct 2022
Cited by 1 | Viewed by 1733
Abstract
The resolution of InGaAs FPA detectors is degraded by the electrical crosstalk, which is especially severe in high–density FPAs. We propose a guard-hole structure to suppress the electrical crosstalk in a planar-type 640 × 512 15 μm InGaAs short wavelength infrared FPA detector. [...] Read more.
The resolution of InGaAs FPA detectors is degraded by the electrical crosstalk, which is especially severe in high–density FPAs. We propose a guard-hole structure to suppress the electrical crosstalk in a planar-type 640 × 512 15 μm InGaAs short wavelength infrared FPA detector. For comparison, the frequently used guard ring is also prepared according to the same processing. The calculation results show that the electrical crosstalk with a guard hole is suppressed from 13.4% to 4.5%, reducing by 66%, while the electrical crosstalk with a guard ring is suppressed to 0.4%. Furthermore, we discuss the effects of the guard ring and the guard hole on the dark current, quantum efficiency, and detectivity. Experimental results show the detector with a guard-hole structure has higher performance compared with the detector with a guard-ring structure, the dark current density is reduced by 60%, the QE is increased by 64.5%, and the detectivity is increased by 1.36 times, respectively. The guard-hole structure provides a novel suppression method for the electrical crosstalk of high-density InGaAs detectors. Full article
(This article belongs to the Special Issue Terahertz and Infrared Metamaterial Devices)
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12 pages, 5301 KiB  
Article
Origami Inspired Laser Scanner
by Yu-Shin Wu and Shao-Kang Hung
Micromachines 2022, 13(10), 1796; https://doi.org/10.3390/mi13101796 - 21 Oct 2022
Viewed by 2145
Abstract
Diverse origami techniques and various selections of paper open new possibilities to create micromachines. By folding paper, this article proposes an original approach to build laser scanners, which manipulate optical beams precisely and realize valuable applications, including laser marking, cutting, engraving, and displaying. [...] Read more.
Diverse origami techniques and various selections of paper open new possibilities to create micromachines. By folding paper, this article proposes an original approach to build laser scanners, which manipulate optical beams precisely and realize valuable applications, including laser marking, cutting, engraving, and displaying. A prototype has been designed, implemented, actuated, and controlled. The experimental results demonstrate that the angular stroke, repeatability, full scale settling time, and resonant frequency are 20°, 0.849 m°, 330 ms, 68 Hz, respectively. Its durability, more than 35 million cycles, shows the potential to carry out serious tasks. Full article
(This article belongs to the Special Issue Origami Devices: Design and Application)
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22 pages, 6085 KiB  
Article
Strategy for Fast Decision on Material System Suitability for Continuous Crystallization Inside a Slug Flow Crystallizer
by Anne Cathrine Kufner, Adrian Krummnow, Andreas Danzer and Kerstin Wohlgemuth
Micromachines 2022, 13(10), 1795; https://doi.org/10.3390/mi13101795 - 21 Oct 2022
Cited by 7 | Viewed by 2189
Abstract
There is an increasing focus on two-phase flow in micro- or mini-structured apparatuses for various manufacturing and measurement instrumentation applications, including the field of crystallization as a separation technique. The slug flow pattern offers salient features for producing high-quality products, since narrow residence [...] Read more.
There is an increasing focus on two-phase flow in micro- or mini-structured apparatuses for various manufacturing and measurement instrumentation applications, including the field of crystallization as a separation technique. The slug flow pattern offers salient features for producing high-quality products, since narrow residence time distribution of liquid and solid phases, intensified mixing and heat exchange, and an enhanced particle suspension are achieved despite laminar flow conditions. Due to its unique features, the slug flow crystallizer (SFC) represents a promising concept for small-scale continuous crystallization achieving high-quality active pharmaceutical ingredients (API). Therefore, a time-efficient strategy is presented in this study to enable crystallization of a desired solid product in the SFC as quickly as possible and without much experimental effort. This strategy includes pre-selection of the solvent/solvent mixture using heuristics, verifying the slug flow stability in the apparatus by considering the static contact angle and dynamic flow behavior, and modeling the temperature-dependent solubility in the supposed material system using perturbed-chain statistical associating fluid theory (PC-SAFT). This strategy was successfully verified for the amino acids l-alanine and l-arginine and the API paracetamol for binary and ternary systems and, thus, represents a general approach for using different material systems in the SFC. Full article
(This article belongs to the Special Issue Droplet-Based Microfluidics: Design, Fabrication and Applications)
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14 pages, 3153 KiB  
Article
A Refined Hot Melt Printing Technique with Real-Time CT Imaging Capability
by Kirsty Muldoon, Zeeshan Ahmad, Yu-Chuan Su, Fan-Gang Tseng, Xing Chen, James A. D. McLaughlin and Ming-Wei Chang
Micromachines 2022, 13(10), 1794; https://doi.org/10.3390/mi13101794 - 21 Oct 2022
Cited by 3 | Viewed by 2103
Abstract
Personalised drug delivery systems with the ability to offer real-time imaging and control release are an advancement in diagnostic and therapeutic applications. This allows for a tailored drug dosage specific to the patient with a release profile that offers the optimum therapeutic effect. [...] Read more.
Personalised drug delivery systems with the ability to offer real-time imaging and control release are an advancement in diagnostic and therapeutic applications. This allows for a tailored drug dosage specific to the patient with a release profile that offers the optimum therapeutic effect. Coupling this application with medical imaging capabilities, real-time contrast can be viewed to display the interaction with the host. Current approaches towards such novelty produce a drug burst release profile and contrasting agents associated with side effects as a result of poor encapsulation of these components. In this study, a 3D-printed drug delivery matrix with real-time imaging is engineered. Polycaprolactone (PCL) forms the bulk structure and encapsulates tetracycline hydrochloride (TH), an antibiotic drug and Iron Oxide Nanoparticles (IONP, Fe3O4), a superparamagnetic contrasting agent. Hot melt extrusion (HME) coupled with fused deposition modelling (FDM) is utilised to promote the encapsulation of TH and IONP. The effect of additives on the formation of micropores (10–20 µm) on the 3D-printed surface was investigated. The high-resolution process demonstrated successful encapsulation of both bioactive and nano components to present promising applications in drug delivery systems, medical imaging and targeted therapy. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Biology and Biomedicine 2022)
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13 pages, 2887 KiB  
Article
A High-Precision Method of Stiffness Axes Identification for Axisymmetric Resonator Gyroscopes
by Junhao Xiong, Kaiyong Yang, Tao Xia, Jingyu Li, Yonglei Jia, Yunfeng Tao, Yao Pan and Hui Luo
Micromachines 2022, 13(10), 1793; https://doi.org/10.3390/mi13101793 - 21 Oct 2022
Cited by 1 | Viewed by 1596
Abstract
Axisymmetric resonators are key elements of Coriolis vibratory gyroscopes (CVGs). The performance of a CVG is closely related to the stiffness and damping symmetry of its resonator. The stiffness symmetry of a resonator can be effectively improved by electrostatic tuning or mechanical trimming, [...] Read more.
Axisymmetric resonators are key elements of Coriolis vibratory gyroscopes (CVGs). The performance of a CVG is closely related to the stiffness and damping symmetry of its resonator. The stiffness symmetry of a resonator can be effectively improved by electrostatic tuning or mechanical trimming, both of which need an accurate knowledge of the azimuth angles of the two stiffness axes of the resonator. Considering that the motion of a non-ideal axisymmetric resonator can be decomposed as two principal oscillations with two different natural frequencies along two orthogonal stiffness axes, this paper introduces a novel high-precision method of stiffness axes identification. The method is based on measurements of the phase difference between the signals detected at two orthogonal sensing electrodes when an axisymmetric resonator is released from all the control forces of the force-to-rebalance mode and from different initial pattern angles. Except for simplicity, our method works with the eight-electrodes configuration, in no need of additional electrodes or detectors. Furthermore, the method is insensitive to the variation of natural frequencies and operates properly in the cases of either large or small frequency splits. The introduced method is tested on a resonator gyroscope, and two stiffness axes azimuth angles are obtained with a resolution better than 0.1°. A comparison of the experimental results and theoretical model simulations confirmed the validity of our method. Full article
(This article belongs to the Special Issue MEMS Inertial Sensors)
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31 pages, 9249 KiB  
Review
MXene/Ferrite Magnetic Nanocomposites for Electrochemical Supercapacitor Applications
by Arun Thirumurugan, Ananthakumar Ramadoss, Shanmuga Sundar Dhanabalan, Sathish-Kumar Kamaraj, Natarajan Chidhambaram, Suyambrakasam Gobalakrishnan, Carolina Venegas Abarzúa, Yerko Alejandro Reyes Caamaño, Rednam Udayabhaskar and Mauricio J. Morel
Micromachines 2022, 13(10), 1792; https://doi.org/10.3390/mi13101792 - 20 Oct 2022
Cited by 10 | Viewed by 4243
Abstract
MXene has been identified as a new emerging material for various applications including energy storage, electronics, and bio-related due to its wider physicochemical characteristics. Further the formation of hybrid composites of MXene with other materials makes them interesting to utilize in multifunctional applications. [...] Read more.
MXene has been identified as a new emerging material for various applications including energy storage, electronics, and bio-related due to its wider physicochemical characteristics. Further the formation of hybrid composites of MXene with other materials makes them interesting to utilize in multifunctional applications. The selection of magnetic nanomaterials for the formation of nanocomposite with MXene would be interesting for the utilization of magnetic characteristics along with MXene. However, the selection of the magnetic nanomaterials is important, as the magnetic characteristics of the ferrites vary with the stoichiometric composition of metal ions, particle shape and size. The selection of the electrolyte is also important for electrochemical energy storage applications, as the electrolyte could influence the electrochemical performance. Further, the external magnetic field also could influence the electrochemical performance. This review briefly discusses the synthesis method of MXene, and ferrite magnetic nanoparticles and their composite formation. We also discussed the recent progress made on the MXene/ferrite nanocomposite for potential applications in electrochemical supercapacitor applications. The possibility of magnetic field-assisted supercapacitor applications with electrolyte and electrode materials are discussed. Full article
(This article belongs to the Special Issue Sustainable Materials for Energy and Environmental Applications)
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18 pages, 8571 KiB  
Article
Dynamic Adaptive Display System for Electrowetting Displays Based on Alternating Current and Direct Current
by Shixiao Li, Yijian Xu, Zhiyu Zhan, Pengyuan Du, Linwei Liu, Zikai Li, Huawei Wang and Pengfei Bai
Micromachines 2022, 13(10), 1791; https://doi.org/10.3390/mi13101791 - 20 Oct 2022
Cited by 4 | Viewed by 1712
Abstract
As a representative of the new reflective display technology, electrowetting display (EWD) technology can be used as a video playback display device due to its fast response characteristics. Direct current (DC) driving brings excellent reflectivity, but static images cannot be displayed continually due [...] Read more.
As a representative of the new reflective display technology, electrowetting display (EWD) technology can be used as a video playback display device due to its fast response characteristics. Direct current (DC) driving brings excellent reflectivity, but static images cannot be displayed continually due to charge trapping, and it can cause afterimages when playing a dynamic video due to contact angle hysteresis. Alternating current (AC) driving brings a good dynamic video refresh ability to EWDs, but that can cause flickers. In this paper, a dynamic adaptive display model based on thin film transistor-electrowetting display (TFT-EWD) was proposed. According to the displayed image content, the TFT-EWD display driver was dynamically adjusted by AC and DC driving models. A DC hybrid driving model was suitable for static image display, which could effectively suppress oil backflow and achieve static image display while ensuring high reflectivity. A source data non-polarized model (SNPM) is an AC driving model which was suitable for dynamic video display and was proposed at the same time. Compared with DC driving, it could obtain smooth display performance with a loss of about 10 absorbance units (A.U.) of reflective luminance, which could solve the flicker problem. With the DC hybrid driving model, the ability to continuously display static images could be obtained with a loss of 2 (A.U.) of luminance. Under the AC driving in SNPM, the reflected luminance was as high as 67 A.U., which was 8 A.U. higher than the source data polarized model (SPM), and it was closer to the reflected luminance under DC driving. Full article
(This article belongs to the Special Issue Advances in Optoelectronic Devices)
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17 pages, 2590 KiB  
Review
Using Chiplet Encapsulation Technology to Achieve Processing-in-Memory Functions
by Wenchao Tian, Bin Li, Zhao Li, Hao Cui, Jing Shi, Yongkun Wang and Jingrong Zhao
Micromachines 2022, 13(10), 1790; https://doi.org/10.3390/mi13101790 - 20 Oct 2022
Cited by 13 | Viewed by 6639
Abstract
With the rapid development of 5G, artificial intelligence (AI), and high-performance computing (HPC), there is a huge increase in the data exchanged between the processor and memory. However, the “storage wall” caused by the von Neumann architecture severely limits the computational performance of [...] Read more.
With the rapid development of 5G, artificial intelligence (AI), and high-performance computing (HPC), there is a huge increase in the data exchanged between the processor and memory. However, the “storage wall” caused by the von Neumann architecture severely limits the computational performance of the system. To efficiently process such large amounts of data and break up the “storage wall”, it is necessary to develop processing-in-memory (PIM) technology. Chiplet combines processor cores and memory chips with advanced packaging technologies, such as 2.5D, 3 dimensions (3D), and fan-out packaging. This improves the quality and bandwidth of signal transmission and alleviates the “storage wall” problem. This paper reviews the Chiplet packaging technology that has achieved the function of PIM in recent years and analyzes some of its application results. First, the research status and development direction of PIM are presented and summarized. Second, the Chiplet packaging technologies that can realize the function of PIM are introduced, which are divided into 2.5D, 3D packaging, and fan-out packaging according to their physical form. Further, the form and characteristics of their implementation of PIM are summarized. Finally, this paper is concluded, and the future development of Chiplet in the field of PIM is discussed. Full article
(This article belongs to the Special Issue Advanced Packaging for Microsystem Applications)
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17 pages, 1526 KiB  
Review
Developments in FRET- and BRET-Based Biosensors
by Yuexin Wu and Tianyu Jiang
Micromachines 2022, 13(10), 1789; https://doi.org/10.3390/mi13101789 - 20 Oct 2022
Cited by 19 | Viewed by 7320
Abstract
Resonance energy transfer technologies have achieved great success in the field of analysis. Particularly, fluorescence resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) provide strategies to design tools for sensing molecules and monitoring biological processes, which promote the development of biosensors. [...] Read more.
Resonance energy transfer technologies have achieved great success in the field of analysis. Particularly, fluorescence resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) provide strategies to design tools for sensing molecules and monitoring biological processes, which promote the development of biosensors. Here, we provide an overview of recent progress on FRET- and BRET-based biosensors and their roles in biomedicine, environmental applications, and synthetic biology. This review highlights FRET- and BRET-based biosensors and gives examples of their applications with their design strategies. The limitations of their applications and the future directions of their development are also discussed. Full article
(This article belongs to the Special Issue Prospects and Challenges of Biosensors towards Diagnostics of the Diseases and Health Monitoring)
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14 pages, 3241 KiB  
Article
Adaptive Feature Extraction for Blood Vessel Segmentation and Contrast Recalculation in Laser Speckle Contrast Imaging
by Eduardo Morales-Vargas, Juan Pablo Padilla-Martinez, Hayde Peregrina-Barreto, Wendy Argelia Garcia-Suastegui and Julio Cesar Ramirez-San-Juan
Micromachines 2022, 13(10), 1788; https://doi.org/10.3390/mi13101788 - 20 Oct 2022
Cited by 2 | Viewed by 2018
Abstract
Microvasculature analysis in biomedical images is essential in the medical area to evaluate diseases by extracting properties of blood vessels, such as relative blood flow or morphological measurements such as diameter. Given the advantages of Laser Speckle Contrast Imaging (LSCI), several studies have [...] Read more.
Microvasculature analysis in biomedical images is essential in the medical area to evaluate diseases by extracting properties of blood vessels, such as relative blood flow or morphological measurements such as diameter. Given the advantages of Laser Speckle Contrast Imaging (LSCI), several studies have aimed to reduce inherent noise to distinguish between tissue and blood vessels at higher depths. These studies have shown that computing Contrast Images (CIs) with Analysis Windows (AWs) larger than standard sizes obtains better statistical estimators. The main issue is that larger samples combine pixels of microvasculature with tissue regions, reducing the spatial resolution of the CI. This work proposes using adaptive AWs of variable size and shape to calculate the features required to train a segmentation model that discriminates between blood vessels and tissue in LSCI. The obtained results show that it is possible to improve segmentation rates of blood vessels up to 45% in high depths (≈900 μm) by extracting features adaptively. The main contribution of this work is the experimentation with LSCI images under different depths and exposure times through adaptive processing methods, furthering the understanding the performance of the different approaches under these conditions. Results also suggest that it is possible to train a segmentation model to discriminate between pixels belonging to blood vessels and those belonging to tissue. Therefore, an adaptive feature extraction method may improve the quality of the features and thus increase the classification rates of blood vessels in LSCI. Full article
(This article belongs to the Special Issue Laser and Optics in Micromachines for Biomedical Applications)
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14 pages, 4908 KiB  
Article
An Adaptive Fusion Attitude and Heading Measurement Method of MEMS/GNSS Based on Covariance Matching
by Wei Sun, Peilun Sun and Jiaji Wu
Micromachines 2022, 13(10), 1787; https://doi.org/10.3390/mi13101787 - 20 Oct 2022
Cited by 5 | Viewed by 1701
Abstract
Aimed at the problem of filter divergence caused by unknown noise statistical characteristics or variable noise characteristics in an MEMS/GNSS integrated navigation system in a dynamic environment, on the basis of revealing the parameter adjustment logic of covariance matching adaptive technology, a fusion [...] Read more.
Aimed at the problem of filter divergence caused by unknown noise statistical characteristics or variable noise characteristics in an MEMS/GNSS integrated navigation system in a dynamic environment, on the basis of revealing the parameter adjustment logic of covariance matching adaptive technology, a fusion adaptive filtering scheme combining innovation-based adaptive estimation (IAE) and the adaptive fading Kalman filter (AFKF) is proposed. By setting two system tuning parameters, for the process noise covariance adaptation loop and the measurement noise covariance adaptation loop, covariance matching is sped up and achieves an effective suppression of filter divergence. The vehicle-mounted experimental results show that the mean square error of the combined attitude error obtained based on the fusion filtering method proposed in this paper is better than 0.5°, and the mean square error of the heading error is better than 1.5°. The results can provide technical support for the continuous extraction of low-cost attitude information from mobile platforms. Full article
(This article belongs to the Special Issue Controls of Micromachines)
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10 pages, 5440 KiB  
Article
Effect of Layer Orientation and Pore Morphology on Water Transport in Multilayered Porous Graphene
by Chulwoo Park, Ferlin Robinson and Daejoong Kim
Micromachines 2022, 13(10), 1786; https://doi.org/10.3390/mi13101786 - 20 Oct 2022
Viewed by 1800
Abstract
In the present work, the effects on water transport due to the orientation of the layer in the multilayered porous graphene and the different patterns formed when the layer is oriented to some degrees are studied for both circular and non-circular pore configurations. [...] Read more.
In the present work, the effects on water transport due to the orientation of the layer in the multilayered porous graphene and the different patterns formed when the layer is oriented to some degrees are studied for both circular and non-circular pore configurations. Interestingly, the five-layered graphene membrane with a layer separation of 3.5 Å used in this study shows that the water transport through multilayered porous graphene can be augmented by introducing an angle to certain layers of the multilayered membrane system. Full article
(This article belongs to the Special Issue Carbon Nanotube-Based Devices)
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11 pages, 3965 KiB  
Article
Serpentine Micromixers Using Extensional Mixing Elements
by George Tomaras, Chandrasekhar R. Kothapalli and Petru S. Fodor
Micromachines 2022, 13(10), 1785; https://doi.org/10.3390/mi13101785 - 20 Oct 2022
Cited by 5 | Viewed by 2468
Abstract
Computational fluid dynamics modeling was used to characterize the effect of the integration of constrictions defined by the vertices of hyperbolas on the flow structure in microfluidic serpentine channels. In the new topology, the Dean flows characteristic of the pressure-driven fluid motion along [...] Read more.
Computational fluid dynamics modeling was used to characterize the effect of the integration of constrictions defined by the vertices of hyperbolas on the flow structure in microfluidic serpentine channels. In the new topology, the Dean flows characteristic of the pressure-driven fluid motion along curved channels are combined with elongational flows and asymmetric longitudinal eddies that develop in the constriction region. The resulting complex flow structure is characterized by folding and stretching of the fluid volumes, which can promote enhanced mixing. Optimization of the geometrical parameters defining the constriction region allows for the development of an efficient micromixer topology that shows robust enhanced performance across a broad range of Reynolds numbers from Re = 1 to 100. Full article
(This article belongs to the Collection Micromixers: Analysis, Design and Fabrication)
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12 pages, 1794 KiB  
Article
Phase-Optimized Peristaltic Pumping by Integrated Microfluidic Logic
by Erik M. Werner, Benjamin X. Lam and Elliot E. Hui
Micromachines 2022, 13(10), 1784; https://doi.org/10.3390/mi13101784 - 20 Oct 2022
Cited by 3 | Viewed by 2553
Abstract
Microfluidic droplet generation typically entails an initial stabilization period on the order of minutes, exhibiting higher variation in droplet volume until the system reaches monodisperse production. The material lost during this period can be problematic when preparing droplets from limited samples such as [...] Read more.
Microfluidic droplet generation typically entails an initial stabilization period on the order of minutes, exhibiting higher variation in droplet volume until the system reaches monodisperse production. The material lost during this period can be problematic when preparing droplets from limited samples such as patient biopsies. Active droplet generation strategies such as antiphase peristaltic pumping effectively reduce stabilization time but have required off-chip control hardware that reduces system accessibility. We present a fully integrated device that employs on-chip pneumatic logic to control phase-optimized peristaltic pumping. Droplet generation stabilizes in about a second, with only one or two non-uniform droplets produced initially. Full article
(This article belongs to the Special Issue Microfluidic Technologies for Medical Diagnosis and Global Health)
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18 pages, 5515 KiB  
Article
Hybrid Compliant Musculoskeletal System for Fast Actuation in Robots
by Pieter Wiersinga, Aidan Sleavin, Bart Boom, Thijs Masmeijer, Spencer Flint and Ed Habtour
Micromachines 2022, 13(10), 1783; https://doi.org/10.3390/mi13101783 - 20 Oct 2022
Cited by 4 | Viewed by 2409
Abstract
A nature-inspired musculoskeletal system is designed and developed to examine the principle of nonlinear elastic energy storage–release for robotic applications. The musculoskeletal system architecture consists of elastically rigid segments and hyperelastic soft materials to emulate rigid–soft interactions in limbless vertebrates. The objectives are [...] Read more.
A nature-inspired musculoskeletal system is designed and developed to examine the principle of nonlinear elastic energy storage–release for robotic applications. The musculoskeletal system architecture consists of elastically rigid segments and hyperelastic soft materials to emulate rigid–soft interactions in limbless vertebrates. The objectives are to (i) improve the energy efficiency of actuation beyond that of current pure soft actuators while (ii) producing a high range of motion similar to that of soft robots but with structural stability. This paper proposes a musculoskeletal design that takes advantage of structural segmentation to increase the system’s degrees of freedom, which enhances the range of motion. Our findings show that rigid–soft interactions provide a remarkable increase in energy storage and release and, thus, an increase in the undulation speed. The energy efficiency achieved is approximately 68% for bending the musculoskeletal system from the straight configuration, compared to 2.5–30% efficiency in purely soft actuators. The hybrid compliance of the musculoskeletal system under investigation shows promise for alleviating the need for actuators at each joint in a robot. Full article
(This article belongs to the Special Issue 3D Printed Actuators)
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10 pages, 21721 KiB  
Article
Millimeter-Wave Permittivity Variations of an HR Silicon Substrate from the Photoconductive Effect
by Charlotte Tripon-Canseliet and Jean Chazelas
Micromachines 2022, 13(10), 1782; https://doi.org/10.3390/mi13101782 - 19 Oct 2022
Cited by 1 | Viewed by 1583
Abstract
The photoinduced microwave complex permittivity of a highly resistive single-crystal silicon wafer was extracted from a bistatic free-space characterization test bench operating in the 26.5–40 GHz frequency band under CW optical illumination at wavelengths of 806 and 971 nm. Significant variations in the [...] Read more.
The photoinduced microwave complex permittivity of a highly resistive single-crystal silicon wafer was extracted from a bistatic free-space characterization test bench operating in the 26.5–40 GHz frequency band under CW optical illumination at wavelengths of 806 and 971 nm. Significant variations in the real and imaginary parts of the substrate’s permittivity induced by direct photoconductivity are reported, with an optical power density dependence, in agreement with the theoretical predictions. These experimental results open the route to ultrafast system reconfiguration of microwave devices in integrated technology by an external EMI-protected and contactless control with unprecedented performance. Full article
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16 pages, 8369 KiB  
Article
Effect of Tool Coatings on Machining Properties of Compacted Graphite Iron
by Xiaonan Ai, Jun Tan, Hui Sun, Lu Lu, Zhenming Yang, Zhongguang Yu, Guojun Liao, Shiyong Li, Yilin Jin, Yusheng Niu, Ning He and Xiuqing Hao
Micromachines 2022, 13(10), 1781; https://doi.org/10.3390/mi13101781 - 19 Oct 2022
Cited by 4 | Viewed by 1644
Abstract
Compacted graphite iron (CGI) has become the most ideal material for automotive engine manufacturing owing to its excellent mechanical properties. However, tools are severely worn during processing, considerably shortening their lifespan. In this study, we prepared a series of cemented carbide-coated tools and [...] Read more.
Compacted graphite iron (CGI) has become the most ideal material for automotive engine manufacturing owing to its excellent mechanical properties. However, tools are severely worn during processing, considerably shortening their lifespan. In this study, we prepared a series of cemented carbide-coated tools and evaluated their coating properties in cutting tests. Among all tested coatings, PVD coating made of AlCrN (AC) presented with the best surface integrity and mechanical properties, achieving the best comprehensive performance in the coating test. The AC-coated tool also exhibited the best cutting performance at a low speed of 120 m/min, corresponding to a 60% longer cutting life and the lowest workpiece surface roughness relative to other coated tools. In the cutting test at a high speed of 350 m/min, the CVD double-layer coated tool (MT) with a TiCN inner layer of and an Al2O3 outer layer had a 70% longer cutting life and the lowest workpiece surface roughness relative to other coated tools. Full article
(This article belongs to the Special Issue Advanced Manufacturing Technology and Systems, 2nd Edition)
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18 pages, 2100 KiB  
Review
Applications of Nano/Micromotors for Treatment and Diagnosis in Biological Lumens
by Shandeng Huang, Yinghua Gao, Yu Lv, Yun Wang, Yinghao Cao, Weisong Zhao, Dongqing Zuo, Haoran Mu and Yingqi Hua
Micromachines 2022, 13(10), 1780; https://doi.org/10.3390/mi13101780 - 19 Oct 2022
Cited by 4 | Viewed by 2825
Abstract
Natural biological lumens in the human body, such as blood vessels and the gastrointestinal tract, are important to the delivery of materials. Depending on the anatomic features of these biological lumens, the invention of nano/micromotors could automatically locomote targeted sites for disease treatment [...] Read more.
Natural biological lumens in the human body, such as blood vessels and the gastrointestinal tract, are important to the delivery of materials. Depending on the anatomic features of these biological lumens, the invention of nano/micromotors could automatically locomote targeted sites for disease treatment and diagnosis. These nano/micromotors are designed to utilize chemical, physical, or even hybrid power in self-propulsion or propulsion by external forces. In this review, the research progress of nano/micromotors is summarized with regard to treatment and diagnosis in different biological lumens. Challenges to the development of nano/micromotors more suitable for specific biological lumens are discussed, and the overlooked biological lumens are indicated for further studies. Full article
(This article belongs to the Special Issue Medical Micro/Nanorobots)
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10 pages, 1773 KiB  
Article
A Hydrogel-Based Self-Sensing Underwater Actuator
by Shuyu Wang, Zhaojia Sun, Shuaiyang Duan, Yuliang Zhao, Xiaopeng Sha, Shifeng Yu and Lei Zuo
Micromachines 2022, 13(10), 1779; https://doi.org/10.3390/mi13101779 - 19 Oct 2022
Cited by 1 | Viewed by 2424
Abstract
Soft robots made of hydrogels are suited for underwater exploration due to their biocompatibility and compliancy. Yet, reaching high dexterity and actuation force for hydrogel-based actuators is challenging. Meanwhile, real-time proprioception is critical for feedback control. Moreover, sensor integration to mimic living organisms [...] Read more.
Soft robots made of hydrogels are suited for underwater exploration due to their biocompatibility and compliancy. Yet, reaching high dexterity and actuation force for hydrogel-based actuators is challenging. Meanwhile, real-time proprioception is critical for feedback control. Moreover, sensor integration to mimic living organisms remains problematic. To address these challenges, we introduce a hydrogel actuator driven by hydraulic force with a fast response (time constant 0.83 s). The highly stretchable and conductive hydrogel (1400% strain) is molded into the PneuNet shape, and two of them are further assembled symmetrically to actuate bi-directionally. Then, we demonstrate its bionic application for underwater swimming, showing 2 cm/s (0.19 BL/s) speed. Inspired by biological neuromuscular systems’ sensory motion, which unifies the sensing and actuation in a single unit, we explore the hydrogel actuator’s self-sensing capacity utilizing strain-induced resistance change. The results show that the soft actuator’s proprioception can monitor the undulation in real-time with a sensitivity of 0.2%/degree. Furthermore, we take a finite-element method and first-order differential equations to model the actuator’s bending in response to pressure. We show that such a model can precisely predict the robot’s bending response over a range of pressures. With the self-sensing actuator and the proposed model, we expect the new approach can lead to future soft robots for underwater exploration with feedback control, and the underlying mechanism of the undulation control might offer significant insights for biomimetic research. Full article
(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)
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20 pages, 1506 KiB  
Article
Activation and Switching of Supramolecular Chemical Signals in Multi-Output Microfluidic Devices
by Artem Bezrukov and Yury Galyametdinov
Micromachines 2022, 13(10), 1778; https://doi.org/10.3390/mi13101778 - 19 Oct 2022
Cited by 4 | Viewed by 2006
Abstract
In this study, we report on the developing of a continuous microfluidic reaction device that allows selective activation of polyelectrolyte-surfactant chemical signals in microflows and switches them between multiple outputs. A numerical model was developed for convection-diffusion reaction processes in reactive polymer-colloid microfluidic [...] Read more.
In this study, we report on the developing of a continuous microfluidic reaction device that allows selective activation of polyelectrolyte-surfactant chemical signals in microflows and switches them between multiple outputs. A numerical model was developed for convection-diffusion reaction processes in reactive polymer-colloid microfluidic flows. Matlab scripts and scaling laws were developed for this model to predict reaction initiation and completion conditions in microfluidic devices and the location of the reaction front. The model allows the optimization of microfluidic device geometry and the setting of operation modes that provide release of the reaction product through specific outputs. Representing a chemical signal, polyelectrolyte-surfactant reaction products create various logic gate states at microfluidic chip outputs. Such systems may have potential as biochemical signal transmitters in organ-on-chip applications or chemical logic gates in cascaded microfluidic devices. Full article
(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)
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24 pages, 19663 KiB  
Article
A Multi-Part Orientation Planning Schema for Fabrication of Non-Related Components Using Additive Manufacturing
by Osama Abdulhameed, Syed Hammad Mian, Khaja Moiduddin, Abdulrahman Al-Ahmari, Naveed Ahmed and Mohamed K. Aboudaif
Micromachines 2022, 13(10), 1777; https://doi.org/10.3390/mi13101777 - 19 Oct 2022
Cited by 2 | Viewed by 2357
Abstract
Additive manufacturing (AM) is a technique that progressively deposits material in layer-by-layer manner (or in additive fashion) for producing a three-dimensional (3D) object, starting from the computer-aided design (CAD) model. This approach allows for the printing of complicated shaped objects and is quickly [...] Read more.
Additive manufacturing (AM) is a technique that progressively deposits material in layer-by-layer manner (or in additive fashion) for producing a three-dimensional (3D) object, starting from the computer-aided design (CAD) model. This approach allows for the printing of complicated shaped objects and is quickly gaining traction in the aerospace, medical implant, jewelry, footwear, automotive, and fashion industries. AM, which was formerly used for single part customization, is currently being considered for mass customization of parts because of its positive impacts. However, part quality and build time are two main impediments to the deployment of AM for mass production. The optimal part orientation is fundamental for maximizing the part’s quality as well as being critical for reducing the fabrication time. This research provides a new method for multi-part AM production that improves quality while reducing overall build time. The automatic setup planning or orientation approach described in this paper employs two objective functions: the quality of the build component and the build time. To tackle the given problem, it introduces a three-step genetic algorithm (GA)-based solution. A feature-based technique is utilized to generate a collection of finite alternative orientations for each component within a specific part group to ensure each part’s individual build quality. Then, a GA was utilized to find the best combination of part build orientations at a global optimal level to reduce material consumption and build time. A case study of orienting nine components concurrently inside a given building chamber was provided for illustration. The findings suggest that the developed technique can increase quality, reduce support waste, and shorten overall production time. When components are positioned optimally rather than in random orientations, build time and support volume are reduced by approximately 7% and 16%, respectively. Full article
(This article belongs to the Special Issue Recent Advances in 3D Printing and Additive Manufacturing)
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21 pages, 5145 KiB  
Article
Design of Improved Flow-Focusing Microchannel with Constricted Continuous Phase Inlet and Study of Fluid Flow Characteristics
by Zhaohui Wang, Weibing Ding, Yiwei Fan, Jian Wang, Jie Chen and Hongxia Wang
Micromachines 2022, 13(10), 1776; https://doi.org/10.3390/mi13101776 - 19 Oct 2022
Cited by 6 | Viewed by 1836
Abstract
This paper proposed an improved flow-focusing microchannel with a constricted continuous phase inlet to increase microbubble generation frequency and reduce microbubbles’ diameter. The design variables were obtained by Latin hypercube sampling, and the radial basis function (RBF) surrogate model was used to establish [...] Read more.
This paper proposed an improved flow-focusing microchannel with a constricted continuous phase inlet to increase microbubble generation frequency and reduce microbubbles’ diameter. The design variables were obtained by Latin hypercube sampling, and the radial basis function (RBF) surrogate model was used to establish the relationship between the objective function (microbubble diameter and generation frequency) and the design variables. Moreover, the optimized design of the nondominated sorting genetic algorithm II (NSGA-II) algorithm was carried out. Finally, the optimization results were verified by numerical simulations and compared with those of traditional microchannels. The results showed that dripping and squeezing regimes existed in the two microchannels. The constricted continuous phase inlet enhanced the flow-focusing effect of the improved microchannel. The diameter of microbubbles obtained from the improved microchannel was reduced from 2.8141 to 1.6949 μm, and the generation frequency was increased from 64.077 to 175.438 kHz at the same capillary numbers (Ca) compared with the traditional microchannel. According to the fitted linear function, it is known that the slope of decreasing microbubble diameter with increasing Ca number and the slope of increasing generation frequency with increasing Ca number are greater in the improved microchannel compared with those in the traditional microchannel. Full article
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8 pages, 1820 KiB  
Article
Zinc Carboxylate Surface Passivation for Enhanced Optical Properties of In(Zn)P Colloidal Quantum Dots
by Doheon Yoo, Eunyoung Bak, Hae Mee Ju, Yoo Min Shin and Min-Jae Choi
Micromachines 2022, 13(10), 1775; https://doi.org/10.3390/mi13101775 - 19 Oct 2022
Cited by 2 | Viewed by 2096
Abstract
Indium phosphide (InP) colloidal quantum dots (CQDs) have generated great interest as next-generation light-emitting materials owing to their narrow emission spectra and environment-friendly components. The minimized surface defects is essential to achieve narrow full-width at half-maximum (FWHM) and high photoluminescence quantum yield (PLQY). [...] Read more.
Indium phosphide (InP) colloidal quantum dots (CQDs) have generated great interest as next-generation light-emitting materials owing to their narrow emission spectra and environment-friendly components. The minimized surface defects is essential to achieve narrow full-width at half-maximum (FWHM) and high photoluminescence quantum yield (PLQY). However, InP CQDs are readily oxidized in ambient condition, which results in formation of oxidation defect states on the surface of InP CQDs. Herein, we introduce a strategy to successfully passivate the surface defects of InP core by zinc complexes. The zinc carboxylates passivation reduces FWHM of InP CQDs from 130 nm to 70 nm and increases PLQY from 1% to 14% without shelling. Furthermore, the photoluminescence (PL) peak has shifted from 670 nm to 510 nm with an increase of zinc carboxylates passivation, which suggests that excessive zinc carboxylates functions as a size-regulating reagent in the synthesis. Full article
(This article belongs to the Special Issue Quantum Dot Frontiers)
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11 pages, 4001 KiB  
Article
Fabrication and Characterization of an Optimized Low-Loss Two-Mode Fiber for Optoacoustic Sensing
by Zelin Zhang, Guanglei You, Yu Qin, Jianqin Peng, Shuhong Xie, Xinli Jiang, Caoyuan Wang, Ruowei Yu, Yichun Shen and Limin Xiao
Micromachines 2022, 13(10), 1774; https://doi.org/10.3390/mi13101774 - 19 Oct 2022
Viewed by 1738
Abstract
An optimized multi-step index (MSI) 2-LP-mode fiber is proposed and fabricated with low propagation loss of 0.179 dB/km, low intermodal crosstalk and excellent bend resistance. We experimentally clarified the characteristics of backward Brillouin scattering (BBS) and forward Brillouin scattering (FBS) induced by radial [...] Read more.
An optimized multi-step index (MSI) 2-LP-mode fiber is proposed and fabricated with low propagation loss of 0.179 dB/km, low intermodal crosstalk and excellent bend resistance. We experimentally clarified the characteristics of backward Brillouin scattering (BBS) and forward Brillouin scattering (FBS) induced by radial acoustic modes (R0,m) in the fabricated MSI 2-LP-mode fiber, respectively. Via the use of this two-mode fiber, we demonstrated a novel discriminative measurement method of temperature and acoustic impedance based on BBS and FBS, achieving improved experimental measurement uncertainties of 0.2 °C and 0.019 kg/(s·mm2) for optoacoustic chemical sensing. The low propagation loss of the sensing fiber and the new measurement method based on both BBS and FBS may pave the way for long-distance and high spatial resolution distributed fiber sensors. Full article
(This article belongs to the Section E：Engineering and Technology)
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18 pages, 6905 KiB  
Review
Advanced MXene-Based Micro- and Nanosystems for Targeted Drug Delivery in Cancer Therapy
by Fatemeh Mohajer, Ghodsi Mohammadi Ziarani, Alireza Badiei, Siavash Iravani and Rajender S. Varma
Micromachines 2022, 13(10), 1773; https://doi.org/10.3390/mi13101773 - 19 Oct 2022
Cited by 17 | Viewed by 4257
Abstract
MXenes with unique mechanical, optical, electronic, and thermal properties along with a specific large surface area for surface functionalization/modification, high electrical conductivity, magnetic properties, biocompatibility, and low toxicity have been explored as attractive candidates for the targeted delivery of drugs in cancer therapy. [...] Read more.
MXenes with unique mechanical, optical, electronic, and thermal properties along with a specific large surface area for surface functionalization/modification, high electrical conductivity, magnetic properties, biocompatibility, and low toxicity have been explored as attractive candidates for the targeted delivery of drugs in cancer therapy. These two-dimensional materials have garnered much attention in the field of cancer therapy since they have shown suitable photothermal effects, biocompatibility, and luminescence properties. However, outstanding challenging issues regarding their pharmacokinetics, biosafety, targeting properties, optimized functionalization, synthesis/reaction conditions, and clinical translational studies still need to be addressed. Herein, recent advances and upcoming challenges in the design of advanced targeted drug delivery micro- and nanosystems in cancer therapy using MXenes have been discussed to motivate researchers to further investigate this field of science. Full article
(This article belongs to the Special Issue Rise of MXenes: A New Family of Two-Dimensional (2D) Materials and Devices)
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7 pages, 2353 KiB  
Article
A Novel Capacitorless 1T DRAM with Embedded Oxide Layer
by Dongxue Zhao, Zhiliang Xia, Tao Yang, Yuancheng Yang, Wenxi Zhou and Zongliang Huo
Micromachines 2022, 13(10), 1772; https://doi.org/10.3390/mi13101772 - 19 Oct 2022
Viewed by 3456
Abstract
A novel vertical dual surrounding gate transistor with embedded oxide layer is proposed for capacitorless single transistor DRAM (1T DRAM). The embedded oxide layer is innovatively used to improve the retention time by reducing the recombination rate of stored holes and sensing electrons. [...] Read more.
A novel vertical dual surrounding gate transistor with embedded oxide layer is proposed for capacitorless single transistor DRAM (1T DRAM). The embedded oxide layer is innovatively used to improve the retention time by reducing the recombination rate of stored holes and sensing electrons. Based on TCAD simulations, the new structure is predicted to not only have the characteristics of fast access, random read and integration of 4F2 cell, but also to realize good retention and deep scaling. At the same time, the new structure has the potential of scaling compared with the conventional capacitorless 1T DRAM. Full article
(This article belongs to the Special Issue Advances in Emerging Nonvolatile Memory, Volume II)
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11 pages, 7215 KiB  
Article
Fabrication of Chiral 3D Microstructure Using Tightly Focused Multiramp Helico-Conical Optical Beams
by Jisen Wen, Qiuyuan Sun, Mengdi Luo, Chengpeng Ma, Zhenyao Yang, Chenyi Su, Chun Cao, Dazhao Zhu, Chenliang Ding, Liang Xu, Cuifang Kuang and Xu Liu
Micromachines 2022, 13(10), 1771; https://doi.org/10.3390/mi13101771 - 18 Oct 2022
Cited by 16 | Viewed by 2511
Abstract
Beams with optical vortices are widely used in various fields, including optical communication, optical manipulation and trapping, and, especially in recent years, in the processing of nanoscale structures. However, circular vortex beams are difficult to use for the processing of chiral micro and [...] Read more.
Beams with optical vortices are widely used in various fields, including optical communication, optical manipulation and trapping, and, especially in recent years, in the processing of nanoscale structures. However, circular vortex beams are difficult to use for the processing of chiral micro and nanostructures. This paper introduces a multiramp helical–conical beam that can produce a three-dimensional spiral light field in a tightly focused system. Using this spiral light beam and the two-photon direct writing technique, micro–nano structures with chiral characteristics in space can be directly written under a single exposure. The fabrication efficiency is more than 20 times higher than the conventional point-by-point writing strategy. The tightly focused properties of the light field were utilized to analyze the field-dependent properties of the micro–nano structure, such as the number of multiramp mixed screw-edge dislocations. Our results enrich the means of two-photon polymerization technology and provide a simple and stable way for the micromachining of chiral microstructures, which may have a wide range of applications in optical tweezers, optical communications, and metasurfaces. Full article
(This article belongs to the Special Issue Optics and Photonics in Micromachines)
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12 pages, 5694 KiB  
Article
Investigation of a 4H-SiC Trench MOSFET with Back-Side Super Junction
by Lili Zhang, Yuxuan Liu, Junpeng Fang and Yanjuan Liu
Micromachines 2022, 13(10), 1770; https://doi.org/10.3390/mi13101770 - 18 Oct 2022
Cited by 1 | Viewed by 2692
Abstract
In this paper, a 4H-SiC trench gate MOSFET, featuring a super junction layer located on the drain-region side, is presented to enhance the breakdown voltage and the figures of merit (FOM). The proposed structure is investigated and compared with the conventional structure with [...] Read more.
In this paper, a 4H-SiC trench gate MOSFET, featuring a super junction layer located on the drain-region side, is presented to enhance the breakdown voltage and the figures of merit (FOM). The proposed structure is investigated and compared with the conventional structure with a 2D numerical simulator—ATLAS. The investigation results have demonstrated that the breakdown voltage in the proposed structure is enhanced by 21.2%, and the FOM is improved by 39.6%. In addition, the proposed structure has an increased short-circuit capability. Full article
(This article belongs to the Special Issue Semiconductor Power Devices: Reliability and Applications)
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