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Micromachines, Volume 14, Issue 9 (September 2023) – 158 articles

Cover Story (view full-size image): The escalating impact of global warming poses a grave threat to the environment, prompting efforts to reduce greenhouse gas emissions. Mechanical energy harvesting can power a growing number of electronic devices. Triboelectric nanogenerators (TENGs) are used as force-responsive sensors. The integration of TENGs with CO2-absorbed materials, like CaCO3, presents an eco-friendly approach to mitigate CO2 emissions. This study proposes a single-electrode TENG with CaCO3 as a self-sustainable triboelectric impact sensor and examines the triboelectric property of CaCO3. The sensor, applied in a slap match game, uses support vector machine algorithms to judge the Ddakji's turning state. This eco-friendly strategy combines energy harvesting and environmental mitigation through CaCO3-based TENGs. View this paper
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21 pages, 14695 KiB  
Article
Pseudo-Desublimation of AdBlue Microdroplets through Selective Catalytic Reduction System Microchannels and Surfaces
by Claudiu Marian Picus, Ioan Mihai and Cornel Suciu
Micromachines 2023, 14(9), 1807; https://doi.org/10.3390/mi14091807 - 21 Sep 2023
Viewed by 1083
Abstract
In the present paper, the occurrence and development of the pseudo-desublimation process of AdBlue microdroplets in the microchannels and surfaces of catalytic reduction systems (SCR) are reported. In order to understand how the pseudo-desublimation process develops, the influence of heat flux values on [...] Read more.
In the present paper, the occurrence and development of the pseudo-desublimation process of AdBlue microdroplets in the microchannels and surfaces of catalytic reduction systems (SCR) are reported. In order to understand how the pseudo-desublimation process develops, the influence of heat flux values on the heat transfer of AdBlue injection was analysed, taking into account the structure of the microchannels inside the SCR and the overall configuration of the installation. The evolution of the AdBlue vapour flow in the SCR system was simulated, as well as the temperature variation along an SCR microchannel through which the mixture flows. An experimental set-up was designed in order to visualise and interpret the processes at the onset of pseudo-desublimation. The results described in this paper confirm the existence of a pseudo-desublimation process that occurs only under certain temperature conditions when AdBlue is injected into SCR systems. The characteristics of the crystals formed and their growth rate depend on the working temperature, which could be controlled by efficient preheating methods immediately after engine start. A better understanding of the process will allow the development of methods of avoiding solid depositions on SCR system components, which has a direct impact on SCR catalyst performance and durability. Full article
(This article belongs to the Special Issue Heat Transfer and Fluid Flow in Microstructures)
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17 pages, 4940 KiB  
Article
A Multi-Layer Breast Cancer Model to Study the Synergistic Effect of Photochemotherapy
by Magdalena Flont and Elżbieta Jastrzębska
Micromachines 2023, 14(9), 1806; https://doi.org/10.3390/mi14091806 - 21 Sep 2023
Viewed by 1354
Abstract
Breast cancer is one of the most common cancers among women. The development of new and effective therapeutic approaches in the treatment of breast cancer is an important challenge in modern oncology. Two-dimensional (2D) cell cultures are most often used in the study [...] Read more.
Breast cancer is one of the most common cancers among women. The development of new and effective therapeutic approaches in the treatment of breast cancer is an important challenge in modern oncology. Two-dimensional (2D) cell cultures are most often used in the study of compounds with potential anti-tumor nature. However, it is necessary to develop advanced three-dimensional (3D) cell models that can, to some extent, reflect the physiological conditions. The use of miniature cancer-on-a-chip microfluidic systems can help to mimic the complex cancer microenvironment. In this report, we developed a 3D breast cancer model in the form of a cell multilayer, composed of stromal cells (HMF) and breast cancer parenchyma (MCF-7). The developed cell model was successfully used to analyze the effectiveness of combined sequential photochemotherapy, based on doxorubicin and meso-tetraphenylporphyrin. We proved that the key factor that allows achieving the synergistic effect of combination therapy are the order of drug administration to the cells and the sequence of therapeutic procedures. To the best of our knowledge, studies on the effectiveness of combination photochemotherapy depending on the sequence of the component drugs were performed for the first time under microfluidic conditions on a 3D multilayered model of breast cancer tissue. Full article
(This article belongs to the Special Issue Biosensors for Biomedical and Environmental Applications, Volume 2)
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17 pages, 5925 KiB  
Article
Design and Analysis of XY Large Travel Micro Stage Based on Secondary Symmetric Lever Amplification
by Tao Zhang, Liuguang Xiong, Zequan Pan, Chunhua Zhang, Wen Qu, Yuhang Wang and Chunmei Yang
Micromachines 2023, 14(9), 1805; https://doi.org/10.3390/mi14091805 - 21 Sep 2023
Cited by 1 | Viewed by 1366
Abstract
This study presents a newly developed piezoelectric drive mechanism for the purpose of designing, analyzing, and testing a micro-positioning platform driven by piezoelectric actuators. The platform incorporates a piezoelectric ceramic actuator and a flexible hinge drive and features a symmetrical two-stage lever (STSL) [...] Read more.
This study presents a newly developed piezoelectric drive mechanism for the purpose of designing, analyzing, and testing a micro-positioning platform driven by piezoelectric actuators. The platform incorporates a piezoelectric ceramic actuator and a flexible hinge drive and features a symmetrical two-stage lever (STSL) amplification mechanism and a parallelogram output structure. The implementation of this design has led to notable enhancements in the dynamic properties of the platform, thereby eliminating the undesired parasitic displacement of the mechanism. An analytical model describing the fully elastic deformation of the platform is established, which is further verified by finite element simulation. Finally, the static and dynamic performances of the platform are comprehensively evaluated through experiments. A closed-loop control strategy is adopted to eliminate the nonlinear hysteresis phenomenon of the piezoceramic actuator (PEA). The experimental results show that the piezoelectric micro-actuator platform has a motion range of 97.84 μm × 98.03 μm; the output coupling displacement error is less than 1%; the resolutions of the two axes are 8.1 nm and 8 nm, respectively; and the x-axis and y-axis trajectory tracking errors are both 0.6%. The piezoelectric micromotion platform has good dynamic properties, precision, and stability. The design has a wide application potential in the field of micro-positioning. Full article
(This article belongs to the Special Issue Micro- and Nano-Systems for Manipulation, Actuation and Sensing)
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17 pages, 1605 KiB  
Article
Modeling of Particulate Pollutants Using a Memory-Based Recurrent Neural Network Implemented on an FPGA
by Julio Alberto Ramírez-Montañez, Jose de Jesús Rangel-Magdaleno, Marco Antonio Aceves-Fernández and Juan Manuel Ramos-Arreguín
Micromachines 2023, 14(9), 1804; https://doi.org/10.3390/mi14091804 - 21 Sep 2023
Viewed by 1056
Abstract
The present work describes the training and subsequent implementation on an FPGA board of an LSTM neural network for the modeling and prediction of the exceedances of criteria pollutants such as nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matter (PM [...] Read more.
The present work describes the training and subsequent implementation on an FPGA board of an LSTM neural network for the modeling and prediction of the exceedances of criteria pollutants such as nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matter (PM10 and PM2.5). Understanding the behavior of pollutants and assessing air quality in specific geographical regions is crucial. Overexposure to these pollutants can cause harm to both natural ecosystems and living organisms, including humans. Therefore, it is essential to develop a solution that can accurately evaluate pollution levels. One potential approach is to implement a modified LSTM neural network on an FPGA board. This implementation obtained an 11% improvement compared to the original LSTM network, demonstrating that the proposed architecture is able to maintain its functionality despite reducing the number of neurons in its initial layers. It shows the feasibility of integrating a prediction network into a limited system such as an FPGA board, but easily coupled to a different system. Importantly, this implementation does not compromise the prediction accuracy for both 24 h and 72 h time frames, highlighting an opportunity for further enhancement and refinement. Full article
(This article belongs to the Special Issue FPGA Applications and Future Trends)
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10 pages, 2701 KiB  
Communication
A Low-Profile Dielectric Resonator Filter with Wide Stopband for High Integration on PCB
by Shixian Lin, Mengdan Wang, Kai Xu and Lingyan Zhang
Micromachines 2023, 14(9), 1803; https://doi.org/10.3390/mi14091803 - 21 Sep 2023
Viewed by 910
Abstract
A low-profile dielectric resonator (DR) filter is proposed to achieve the feature of high integration and wide stopband. The high integration is due to the structure of printed circuit board (PCB) substrate instead of metal cavity, which can be easily integrated with other [...] Read more.
A low-profile dielectric resonator (DR) filter is proposed to achieve the feature of high integration and wide stopband. The high integration is due to the structure of printed circuit board (PCB) substrate instead of metal cavity, which can be easily integrated with other planar circuits. Thus, the proposed design can improve the integration level and reduce installation errors. Moreover, the out-of-band harmonics can be well suppressed by the structure combined with introducing rectangular hollowing in the center of the dielectric block, coupling the feed and loading 1/4λ wavelength branch. For demonstration, it is fabricated and measured. The simulated and experimental results with good agreement are presented, the insertion loss is as low as 1.1 dB, the profile height is only 0.77λg, and the stopband reaches 2.61f0. Full article
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20 pages, 6427 KiB  
Article
Design of a Penta-Band Graphene-Based Terahertz Metamaterial Absorber with Fine Sensing Performance
by Runing Lai, Hao Chen, Zigang Zhou, Zao Yi, Bin Tang, Jing Chen, Yougen Yi, Chaojun Tang, Jianguo Zhang and Tangyou Sun
Micromachines 2023, 14(9), 1802; https://doi.org/10.3390/mi14091802 - 21 Sep 2023
Cited by 43 | Viewed by 2080
Abstract
This paper presents a new theoretical proposal for a surface plasmon resonance (SPR) terahertz metamaterial absorber with five narrow absorption peaks. The overall structure comprises a sandwich stack consisting of a gold bottom layer, a silica medium, and a single-layer patterned graphene array [...] Read more.
This paper presents a new theoretical proposal for a surface plasmon resonance (SPR) terahertz metamaterial absorber with five narrow absorption peaks. The overall structure comprises a sandwich stack consisting of a gold bottom layer, a silica medium, and a single-layer patterned graphene array on top. COMSOL simulation represents that the five absorption peaks under TE polarization are at fI = 1.99 THz (95.82%), f = 6.00 THz (98.47%), f = 7.37 THz (98.72%), f = 8.47 THz (99.87%), and fV = 9.38 THz (97.20%), respectively, which is almost consistent with the absorption performance under TM polarization. In contrast to noble metal absorbers, its absorption rates and resonance frequencies can be dynamically regulated by controlling the Fermi level and relaxation time of graphene. In addition, the device can maintain high absorptivity at 0~50° in TE polarization and 0~40° in TM polarization. The maximum refractive index sensitivity can reach SV = 1.75 THz/RIU, and the maximum figure of merit (FOM) can reach FOMV = 12.774 RIU−1. In conclusion, our design has the properties of dynamic tunability, polarization independence, wide-incident-angle absorption, and fine refractive index sensitivity. We believe that the device has potential applications in photodetectors, active optoelectronic devices, sensors, and other related fields. Full article
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18 pages, 7476 KiB  
Article
Microscale Engineering of n-Type Doping in Nanostructured Gallium Antimonide: AC Impedance Spectroscopy Insights on Grain Boundary Characterization and Strategies for Controlled Dopant Distribution
by Michael J. Hall and Daryoosh Vashaee
Micromachines 2023, 14(9), 1801; https://doi.org/10.3390/mi14091801 - 21 Sep 2023
Viewed by 1001
Abstract
This paper investigates the microscale engineering aspects of n-type doped GaSb to address the challenges associated with achieving high electrical conductivity and precise dopant distribution in this semiconductor material. AC impedance spectroscopy is employed as a reliable technique to characterize the microstructural and [...] Read more.
This paper investigates the microscale engineering aspects of n-type doped GaSb to address the challenges associated with achieving high electrical conductivity and precise dopant distribution in this semiconductor material. AC impedance spectroscopy is employed as a reliable technique to characterize the microstructural and electrical properties of GaSb, providing valuable insights into the impact of grain boundaries on overall electrical performance. The uneven distribution of dopants, caused by diffusion, and the incomplete activation of introduced dopants pose significant obstacles in achieving consistent material properties. To overcome these challenges, a careful selection of alloying elements, such as bismuth, is explored to suppress the formation of native acceptor defects and modulate band structures, thereby influencing the doping and compensator formation processes. Additionally, the paper examines the effect of microwave annealing as a potential solution for enhancing dopant activation, minimizing diffusion, and reducing precipitate formation. Microwave annealing shows promise due to its rapid heating and shorter processing times, making it a viable alternative to traditional annealing methods. The study underscores the need for a stable grain boundary passivation strategy to achieve significant improvements in GaSb material performance. Simple grain size reduction strategies alone do not result in better thermoelectric performance, for example, and increasing the grain boundary area per unit volume exacerbates the issue of free carrier compensation. These findings highlight the complexity of achieving optimal doping in GaSb materials and the importance of innovative analytical techniques and controlled doping processes. The comprehensive exploration of n-type doped GaSb presented in this research provides valuable insights for future advancements in the synthesis and optimization of high-conductivity nanostructured n-type GaSb, with potential applications in thermoelectric devices and other electronic systems. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in 'Materials and Processing' 2023)
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15 pages, 3351 KiB  
Article
Effect of Substrate Negative Bias on the Microstructural, Optical, Mechanical, and Laser Damage Resistance Properties of HfO2 Thin Films Grown by DC Reactive Magnetron Sputtering
by Yingxue Xi, Xinghui Qin, Wantong Li, Xi Luo, Jin Zhang, Weiguo Liu and Pengfei Yang
Micromachines 2023, 14(9), 1800; https://doi.org/10.3390/mi14091800 - 21 Sep 2023
Viewed by 1154
Abstract
Hafnium oxide thin films have attracted great attention as promising materials for applications in the field of optical thin films and microelectronic devices. In this paper, hafnium oxide thin films were prepared via DC magnetron sputtering deposition on a quartz substrate. The influence [...] Read more.
Hafnium oxide thin films have attracted great attention as promising materials for applications in the field of optical thin films and microelectronic devices. In this paper, hafnium oxide thin films were prepared via DC magnetron sputtering deposition on a quartz substrate. The influence of various negative biases on the structure, morphology, and mechanical and optical properties of the obtained films were also evaluated. XRD results indicated that (1¯11)-oriented thin films with a monoclinic phase could be obtained under the non-bias applied conditions. Increasing the negative bias could refine the grain size and inhibit the grain preferred orientation of the thin films. Moreover, the surface quality and mechanical and optical properties of the films could be improved significantly along with the increase in the negative bias and then deteriorated as the negative bias voltage arrived at −50 V. It is evident that the negative bias is an effective modulation means to modify the microstructural, mechanical, and optical properties of the films. Full article
(This article belongs to the Special Issue Advanced Thin-Films: Design, Fabrication and Applications)
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25 pages, 6117 KiB  
Article
Surface Acoustic Wave-Based Microfluidic Device for Microparticles Manipulation: Effects of Microchannel Elasticity on the Device Performance
by Gianluca Mezzanzanica, Olivier Français and Stefano Mariani
Micromachines 2023, 14(9), 1799; https://doi.org/10.3390/mi14091799 - 21 Sep 2023
Viewed by 1903
Abstract
Size sorting, line focusing, and isolation of microparticles or cells are fundamental ingredients in the improvement of disease diagnostic tools adopted in biology and biomedicine. Microfluidic devices are exploited as a solution to transport and manipulate (bio)particles via a liquid flow. Use of [...] Read more.
Size sorting, line focusing, and isolation of microparticles or cells are fundamental ingredients in the improvement of disease diagnostic tools adopted in biology and biomedicine. Microfluidic devices are exploited as a solution to transport and manipulate (bio)particles via a liquid flow. Use of acoustic waves traveling through the fluid provides non-contact solutions to the handling goal, by exploiting the acoustophoretic phenomenon. In this paper, a finite element model of a microfluidic surface acoustic wave-based device for the manipulation of microparticles is reported. Counter-propagating waves are designed to interfere inside a PDMS microchannel and generate a standing surface acoustic wave which is transmitted to the fluid as a standing pressure field. A model of the cross-section of the device is considered to perform a sensitivity analysis of such a standing pressure field to uncertainties related to the geometry of the microchannel, especially in terms of thickness and width of the fluid domain. To also assess the effects caused by possible secondary waves traveling in the microchannel, the PDMS is modeled as an elastic solid material. Remarkable effects and possible issues in microparticle actuation, as related to the size of the microchannel, are discussed by way of exemplary results. Full article
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14 pages, 5685 KiB  
Article
A Highly Flexible Piezoelectric Ultrasonic Sensor for Wearable Bone Density Testing
by Zhiqiang Song, Bozhi Wang, Zhuo Zhang, Yirong Yu and Dabin Lin
Micromachines 2023, 14(9), 1798; https://doi.org/10.3390/mi14091798 - 20 Sep 2023
Cited by 1 | Viewed by 2022
Abstract
Driven by the loss of bone calcium, the elderly are prone to osteoporosis, and regular routine checks on bone status are necessary, which mainly rely on bone testing equipment. Therefore, wearable real-time healthcare devices have become a research hotspot. Herein, we designed a [...] Read more.
Driven by the loss of bone calcium, the elderly are prone to osteoporosis, and regular routine checks on bone status are necessary, which mainly rely on bone testing equipment. Therefore, wearable real-time healthcare devices have become a research hotspot. Herein, we designed a high-performance flexible ultrasonic bone testing system using axial transmission technology based on quantitative ultrasound theory. First, a new rare-earth-element-doped PMN-PZT piezoelectric ceramic was synthesized using a solid-state reaction, and characterized by X-ray diffraction and SEM. Both a high piezoelectric coefficient d33 = 525 pC/N and electromechanical coupling factors of k33 = 0.77, kt = 0.58 and kp = 0.63 were achieved in 1%La/Sm-doped 0.17 PMN-0.47 PZ-0.36 PT ceramics. Combining a flexible PDMS substrate with an ultrasonic array, a flexible hardware circuit was designed which includes a pulse excitation module, ultrasound array module, amplification module, filter module, digital-to-analog conversion module and wireless transmission module, showing high power transfer efficiency and power intensity with values of 35% and 55.4 mW/cm2, respectively. Finally, the humerus, femur and fibula were examined by the flexible device attached to the skin, and the bone condition was displayed in real time on the mobile client, which indicates the potential clinical application of this device in the field of wearable healthcare. Full article
(This article belongs to the Topic Piezoelectric Materials and Applications)
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12 pages, 12130 KiB  
Article
Research on the Preparation and Application of Fixed-Abrasive Tools Based on Solid-Phase Reactions for Sapphire Wafer Lapping and Polishing
by Linlin Cao, Xiaolong Zhou, Yingjie Wang, Zhilun Yang, Duowen Chen, Wei Wei and Kaibao Wang
Micromachines 2023, 14(9), 1797; https://doi.org/10.3390/mi14091797 - 20 Sep 2023
Cited by 1 | Viewed by 1184
Abstract
Single-crystal sapphire specimen (α-Al2O3) have been widely applied in the semiconductor industry, microelectronics, and so on. In order to shorten the production time and improve the processing efficiency of sapphire processing, an integrated fixed-abrasive tool (FAT) based on solid-phase [...] Read more.
Single-crystal sapphire specimen (α-Al2O3) have been widely applied in the semiconductor industry, microelectronics, and so on. In order to shorten the production time and improve the processing efficiency of sapphire processing, an integrated fixed-abrasive tool (FAT) based on solid-phase reactions is proposed in this article. The optimal FAT composition is determined using a preliminary experiment and orthogonal experiments. The mass fraction of the abrasives is chosen as 55 wt%, and the mass ratio of SiO2/Cr2O3 is 2. Surface roughness Ra decreased from 580.4 ± 52.7 nm to 8.1 ± 0.7 nm after 150 min, and the average material removal rate was 14.3 ± 1.2 nm/min using the prepared FAT. Furthermore, FAT processing combined with chemical mechanical polishing (CMP) was shortened by 1.5 h compared to the traditional sapphire production process in obtaining undamaged sapphire surfaces with a roughness of Ra < 0.4 nm, which may have the potential to take the place of the fine lapping and rough polishing process. Full article
(This article belongs to the Special Issue High-Quality Surface Integrity of Ultra-Precision Machining)
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12 pages, 3469 KiB  
Article
Raman Lasing in a Tellurite Microsphere with Thermo-Optical on/off Switching by an Auxiliary Laser Diode
by Elena A. Anashkina, Maria P. Marisova, Vitaly V. Dorofeev and Alexey V. Andrianov
Micromachines 2023, 14(9), 1796; https://doi.org/10.3390/mi14091796 - 20 Sep 2023
Cited by 2 | Viewed by 1036
Abstract
The generation of coherent light based on inelastic stimulated Raman scattering in photonic microresonators has been attracting great interest in recent years. Tellurite glasses are promising materials for such microdevices since they have large Raman gain and large Raman frequency shift. We experimentally [...] Read more.
The generation of coherent light based on inelastic stimulated Raman scattering in photonic microresonators has been attracting great interest in recent years. Tellurite glasses are promising materials for such microdevices since they have large Raman gain and large Raman frequency shift. We experimentally obtained Raman lasing at a wavelength of 1.8 µm with a frequency shift of 27.5 THz from a 1.54 µm narrow-line pump in a 60 µm tellurite glass microsphere with a Q-factor of 2.5 × 107. We demonstrated experimentally a robust, simple, and cheap way of thermo-optically controlled on/off switching of Raman lasing in a tellurite glass microsphere by an auxiliary laser diode. With a permanently operating narrow-line pump laser, on/off switching of the auxiliary 405 nm laser diode led to off/on switching of Raman generation. We also performed theoretical studies supporting the experimental results. The temperature distribution and thermal frequency shifts in eigenmodes in the microspheres heated by the thermalized power of an auxiliary diode and the partially thermalized power of a pump laser were numerically simulated. We analyzed the optical characteristics of Raman generation in microspheres of different diameters. The numerical results were in good agreement with the experimental ones. Full article
(This article belongs to the Special Issue New Advances in Micromachined Resonators)
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20 pages, 8327 KiB  
Article
Design and Mixing Analysis of a Passive Micromixer Based on Curly Baffles
by Makhsuda Juraeva and Dong-Jin Kang
Micromachines 2023, 14(9), 1795; https://doi.org/10.3390/mi14091795 - 20 Sep 2023
Cited by 2 | Viewed by 1447
Abstract
A novel passive micromixer based on curly baffles is proposed and optimized through the signal-to-noise analysis of various design parameters. The mixing performance of the proposed design was evaluated across a wide Reynolds number range, from 0.1 to 80. Through the analysis, the [...] Read more.
A novel passive micromixer based on curly baffles is proposed and optimized through the signal-to-noise analysis of various design parameters. The mixing performance of the proposed design was evaluated across a wide Reynolds number range, from 0.1 to 80. Through the analysis, the most influential parameter was identified, and its value was found to be constant regardless of the mixing mechanism. The optimized design, refined using the signal-to-noise analysis, demonstrated a significant enhancement of mixing performance, particularly in the low Reynolds number range (Re< 10). The design set obtained at the diffusion dominance range shows the highest degree of mixing (DOM) in the low Reynolds number range of Re< 10, while the design set optimized for the convection dominance range exhibited the least pressure drop across the entire Reynolds number spectrum (Re< 80). The present design approach proved to be a practical tool for identifying the most influential design parameter and achieving excellent mixing and pressure drop characteristics. The enhancement is mainly due to the curvature of the most influential design parameter. Full article
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10 pages, 16764 KiB  
Article
Comparison of Microcomb-Based Radio-Frequency Photonic Transversal Signal Processors Implemented with Discrete Components Versus Integrated Chips
by Yang Sun, Jiayang Wu, Yang Li and David J. Moss
Micromachines 2023, 14(9), 1794; https://doi.org/10.3390/mi14091794 - 20 Sep 2023
Cited by 1 | Viewed by 995
Abstract
RF photonic transversal signal processors, which combine reconfigurable electrical digital signal processing and high-bandwidth photonic processing, provide a powerful solution for achieving adaptive high-speed information processing. Recent progress in optical microcomb technology provides compelling multi-wavelength sources with a compact footprint, yielding a variety [...] Read more.
RF photonic transversal signal processors, which combine reconfigurable electrical digital signal processing and high-bandwidth photonic processing, provide a powerful solution for achieving adaptive high-speed information processing. Recent progress in optical microcomb technology provides compelling multi-wavelength sources with a compact footprint, yielding a variety of microcomb-based RF photonic transversal signal processors with either discrete or integrated components. Although they operate based on the same principle, the processors in these two forms exhibit distinct performances. This paper presents a comparative investigation of their performances. First, we compare the performances of state-of-the-art processors, focusing on the processing accuracy. Next, we analyze various factors that contribute to the performance differences, including the tap number and imperfect response of experimental components. Finally, we discuss the potential for future improvement. These results provide a comprehensive comparison of microcomb-based RF photonic transversal signal processors implemented using discrete and integrated components and provide insights for their future development. Full article
(This article belongs to the Special Issue Novel Integrated Photonic Devices Incorporating 2D Materials)
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16 pages, 13474 KiB  
Article
High-Performance All-Optical Logic Operations Using Ψ-Shaped Silicon Waveguides at 1.55 μm
by Amer Kotb, Kyriakos E. Zoiros and Chunlei Guo
Micromachines 2023, 14(9), 1793; https://doi.org/10.3390/mi14091793 - 19 Sep 2023
Cited by 2 | Viewed by 1219
Abstract
We simulate with FDTD solutions a complete family of basic Boolean logic operations, which includes XOR, AND, OR, NOT, NOR, NAND, and XNOR, by using compact Ψ-shaped silicon-on-silica optical waveguides that are operated at a 1.55 μm telecommunications wavelength. Four identical slots and [...] Read more.
We simulate with FDTD solutions a complete family of basic Boolean logic operations, which includes XOR, AND, OR, NOT, NOR, NAND, and XNOR, by using compact Ψ-shaped silicon-on-silica optical waveguides that are operated at a 1.55 μm telecommunications wavelength. Four identical slots and one microring resonator, all made of silicon deposited on silica, compose the adopted waveguide. The operating principle of these logic gates is based on the constructive and destructive interferences that result from the phase differences incurred by the launched input optical beams. The performance of these logic operations is evaluated against the contrast ratio (CR) metric. The obtained results suggest that the considered functions designed with the employed waveguide can be realized all-optically with higher CRs and faster speeds than other reported designs. Full article
(This article belongs to the Special Issue Photonic and Optoelectronic Devices and Systems)
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25 pages, 3436 KiB  
Review
Microfluidic Wearable Devices for Sports Applications
by Fangyuan Ju, Yujie Wang, Binfeng Yin, Mengyun Zhao, Yupeng Zhang, Yuanyuan Gong and Changgeng Jiao
Micromachines 2023, 14(9), 1792; https://doi.org/10.3390/mi14091792 - 19 Sep 2023
Cited by 3 | Viewed by 2555
Abstract
This study aimed to systematically review the application and research progress of flexible microfluidic wearable devices in the field of sports. The research team thoroughly investigated the use of life signal-monitoring technology for flexible wearable devices in the domain of sports. In addition, [...] Read more.
This study aimed to systematically review the application and research progress of flexible microfluidic wearable devices in the field of sports. The research team thoroughly investigated the use of life signal-monitoring technology for flexible wearable devices in the domain of sports. In addition, the classification of applications, the current status, and the developmental trends of similar products and equipment were evaluated. Scholars expect the provision of valuable references and guidance for related research and the development of the sports industry. The use of microfluidic detection for collecting biomarkers can mitigate the impact of sweat on movements that are common in sports and can also address the issue of discomfort after prolonged use. Flexible wearable gadgets are normally utilized to monitor athletic performance, rehabilitation, and training. Nevertheless, the research and development of such devices is limited, mostly catering to professional athletes. Devices for those who are inexperienced in sports and disabled populations are lacking. Conclusions: Upgrading microfluidic chip technology can lead to accurate and safe sports monitoring. Moreover, the development of multi-functional and multi-site devices can provide technical support to athletes during their training and competitions while also fostering technological innovation in the field of sports science. Full article
(This article belongs to the Special Issue Recent Development of Micro/Nanofluidic Devices)
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14 pages, 3460 KiB  
Article
Cinnamate-Intercalated Layered Yttrium Hydroxide: UV Light-Responsive Switchable Material
by Maria A. Teplonogova, Alexey D. Yapryntsev, Alexander E. Baranchikov and Vladimir K. Ivanov
Micromachines 2023, 14(9), 1791; https://doi.org/10.3390/mi14091791 - 19 Sep 2023
Cited by 1 | Viewed by 1532
Abstract
In recent years, there has been an increasing interest in stimuli-responsive host–guest materials due to the high potential for their application in switchable devices. Light is the most convenient stimulus for operating these materials; a light-responsive guest affects the host structure and the [...] Read more.
In recent years, there has been an increasing interest in stimuli-responsive host–guest materials due to the high potential for their application in switchable devices. Light is the most convenient stimulus for operating these materials; a light-responsive guest affects the host structure and the functional characteristics of the entire material. UV-transparent layered rare earth hydroxides intercalated with UV-switchable anions are promising candidates as stimuli-responsive host–guest materials. The interlayer distance in the layered rare earth hydroxides depends on the size of the intercalated anions, which could be changed in situ, e.g., via anion isomerisation. Nevertheless, for layered rare earth hydroxides, the possibility of such changes has not been reported yet. A good candidate anion that is capable of intercalating into the interlayer space is the cinnamate anion, which undergoes UV-assisted irreversible trans–cis isomerisation. In this work, both trans- and cis-cinnamate anions were intercalated in layered yttrium hydroxide (LYH). Upon UV-irradiation, the interlayer distance of trans-cinnamate-intercalated layered yttrium hydroxide suspended in isopropanol changed from 21.9 to 20.6 Å. For the first time, the results obtained demonstrate the possibility of using layered rare earth hydroxides as stimuli-responsive materials. Full article
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26 pages, 4038 KiB  
Article
Nonlinear Thermal/Mechanical Buckling of Orthotropic Annular/Circular Nanoplate with the Nonlocal Strain Gradient Model
by Mostafa Sadeghian, Arvydas Palevicius and Giedrius Janusas
Micromachines 2023, 14(9), 1790; https://doi.org/10.3390/mi14091790 - 19 Sep 2023
Cited by 3 | Viewed by 1088
Abstract
This article presents the nonlinear investigation of the thermal and mechanical buckling of orthotropic annular/circular single-layer/bilayer nanoplate with the Pasternak and Winkler elastic foundations based on the nonlocal strain gradient theory. The stability equations of the graphene plate are derived using higher-order shear [...] Read more.
This article presents the nonlinear investigation of the thermal and mechanical buckling of orthotropic annular/circular single-layer/bilayer nanoplate with the Pasternak and Winkler elastic foundations based on the nonlocal strain gradient theory. The stability equations of the graphene plate are derived using higher-order shear deformation theory (HSDT) and first-order shear deformation theory (FSDT) considering nonlinear von Karman strains. Furthermore, this paper analyses the nonlinear thermal and mechanical buckling of the orthotropic bilayer annular/circular nanoplate. HSDT provides an appropriate distribution for shear stress in the thickness direction, removes the limitation of the FSDT, and provides proper precision without using a shear correction coefficient. To solve the stability equations, the differential quadratic method (DQM) is employed. Additionally, for validation, the results are checked with available papers. The effects of strain gradient coefficient, nonlocal parameter, boundary conditions, elastic foundations, and geometric dimensions are studied on the results of the nondimensional buckling loads. Finally, an equation is proposed in which the thermal buckling results can be obtained from mechanical results (or vice versa). Full article
(This article belongs to the Special Issue N/MEMS Intelligent Structures: Design, Manufacturing, and Control)
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21 pages, 22386 KiB  
Article
Low Power Compact 3D-Constructed AlScN Piezoelectric MEMS Mirrors for Various Scanning Strategies
by Jeong-Yeon Hwang, Lena Wysocki, Erdem Yarar, Gunnar Wille, Fin Röhr, Jörg Albers and Shanshan Gu-Stoppel
Micromachines 2023, 14(9), 1789; https://doi.org/10.3390/mi14091789 - 19 Sep 2023
Cited by 3 | Viewed by 2123
Abstract
In this paper, the newly developed 3D-constructed AlScN piezoelectric MEMS mirror is presented. This paper describes the structure and driving mechanism of the proposed mirror device, covering its driving characteristics in both quasi-static and resonant scan modes. Particularly, this paper deals with various [...] Read more.
In this paper, the newly developed 3D-constructed AlScN piezoelectric MEMS mirror is presented. This paper describes the structure and driving mechanism of the proposed mirror device, covering its driving characteristics in both quasi-static and resonant scan modes. Particularly, this paper deals with various achievable scan patterns including 1D line scan and 2D area scan capabilities and driving methods to realize each scanning strategy. Bidirectional quasi-static actuation along horizontal, vertical, and diagonal scanning directions was experimentally characterized and even under a low voltage level of ±20 V, a total optical scan angle of 10.4° was achieved. In addition, 1D line scanning methods using both resonant and non-resonant frequencies were included and a total optical scan angle of 14° was obtained with 100 mVpp under out-of-phase actuation condition. Furthermore, 2D scan patterns including Lissajous, circular and spiral, and raster scans were realized. Diverse scan patterns were realized with the presented AlScN-based MEMS mirror device even under a low level of applied voltage. Further experiments using high voltage up to ±120 V to achieve an enhanced quasi-static scan angle of more than 20° are ongoing to ensure repeatability. This multi-functional MEMS mirror possesses the potential to implement multiple scanning strategies suitable for various application purposes. Full article
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11 pages, 5072 KiB  
Article
Impact of Deposition Power and Gas Flow Ratio on the Tribological Properties of Titanium Vanadium Nitride Thin Films
by Kamlesh V. Chauhan, Sushant Rawal, Nicky P. Patel and Dattatraya G. Subhedar
Micromachines 2023, 14(9), 1788; https://doi.org/10.3390/mi14091788 - 19 Sep 2023
Cited by 1 | Viewed by 1082
Abstract
Magnetron sputtering was used for producing titanium vanadium nitride (TiVN) coatings on brass substrates. In this research, we investigate how changing the sputtering power and nitrogen:argon (N2:Ar) gas ratio affects the structural and tribological properties of TiVN coatings. A scanning electron [...] Read more.
Magnetron sputtering was used for producing titanium vanadium nitride (TiVN) coatings on brass substrates. In this research, we investigate how changing the sputtering power and nitrogen:argon (N2:Ar) gas ratio affects the structural and tribological properties of TiVN coatings. A scanning electron microscope (SEM) was used to examine TiVN coating surface morphology. Both variants showed a gradual increase in the intensity of the TiVN coatings’ (111) and (222) peaks. The TiVN coatings’ tribological properties were examined using a pin-on-disc tribometer with varying loads, speeds, and sliding distances. The wear rates of TiVN-coated brass pins were in the range of 2.5 × 10−4 to 9.14 × 10−4 mm3/Nm depending on load, sliding distance, and gas ratio variation, when compared to the wear rates of TiVN-coated brass pins deposited at various powers, which ranged from 1.76 × 10−3 to 5.87 × 10−3 mm3/Nm. Full article
(This article belongs to the Special Issue Nano-Coating: Design, Fabrication and Applications)
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40 pages, 38086 KiB  
Article
A Novel Approach for Dry Cutting Inconel 718 in a More Sustainable and Low-Cost Way by Actively and Purposely Utilizing the Built-Up Layer
by Xiaoqi Song, Weiming He and Tohru Ihara
Micromachines 2023, 14(9), 1787; https://doi.org/10.3390/mi14091787 - 19 Sep 2023
Cited by 1 | Viewed by 1300
Abstract
Due to its physical and mechanical properties, Inconel 718 remains a difficult-to-cut material and there is an urgent need to develop a more sustainable and low-cost way to machine it. A novel approach for dry cutting Inconel 718 by actively and purposely utilizing [...] Read more.
Due to its physical and mechanical properties, Inconel 718 remains a difficult-to-cut material and there is an urgent need to develop a more sustainable and low-cost way to machine it. A novel approach for dry cutting Inconel 718 by actively and purposely utilizing the built-up layer (BUL), which can be called the self-protective tool (SPT) method, is proposed and investigated in detail in this paper. Various cutting experiments were carried out using the age-treated Inconel 718 and uncoated cemented carbide tools. The formation condition of the BUL, its formation mechanism, its stability, and its protective effect were examined by measuring the tools after cutting using a scanning electron microscope (SEM) and laser confocal microscopy (LCM). The influences of BUL on the cutting process were investigated using cutting force analysis and surface roughness analysis. The results confirmed that the stability of the BUL is very high, and the BUL can not only significantly protect the tool from wear but also reduce friction at the tool–chip interface and maintain surface roughness. It also revealed that the height of the BUL can play a very important role in its protective effect. Comparative experiments verified the effectiveness and generalizability of the proposed SPT method. Full article
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93 pages, 12590 KiB  
Review
Bio-Inspired Nanomaterials for Micro/Nanodevices: A New Era in Biomedical Applications
by Mohammad Harun-Ur-Rashid, Israt Jahan, Tahmina Foyez and Abu Bin Imran
Micromachines 2023, 14(9), 1786; https://doi.org/10.3390/mi14091786 - 18 Sep 2023
Cited by 24 | Viewed by 6909
Abstract
Exploring bio-inspired nanomaterials (BINMs) and incorporating them into micro/nanodevices represent a significant development in biomedical applications. Nanomaterials, engineered to imitate biological structures and processes, exhibit distinctive attributes such as exceptional biocompatibility, multifunctionality, and unparalleled versatility. The utilization of BINMs demonstrates significant potential in [...] Read more.
Exploring bio-inspired nanomaterials (BINMs) and incorporating them into micro/nanodevices represent a significant development in biomedical applications. Nanomaterials, engineered to imitate biological structures and processes, exhibit distinctive attributes such as exceptional biocompatibility, multifunctionality, and unparalleled versatility. The utilization of BINMs demonstrates significant potential in diverse domains of biomedical micro/nanodevices, encompassing biosensors, targeted drug delivery systems, and advanced tissue engineering constructs. This article thoroughly examines the development and distinctive attributes of various BINMs, including those originating from proteins, DNA, and biomimetic polymers. Significant attention is directed toward incorporating these entities into micro/nanodevices and the subsequent biomedical ramifications that arise. This review explores biomimicry’s structure–function correlations. Synthesis mosaics include bioprocesses, biomolecules, and natural structures. These nanomaterials’ interfaces use biomimetic functionalization and geometric adaptations, transforming drug delivery, nanobiosensing, bio-inspired organ-on-chip systems, cancer-on-chip models, wound healing dressing mats, and antimicrobial surfaces. It provides an in-depth analysis of the existing challenges and proposes prospective strategies to improve the efficiency, performance, and reliability of these devices. Furthermore, this study offers a forward-thinking viewpoint highlighting potential avenues for future exploration and advancement. The objective is to effectively utilize and maximize the application of BINMs in the progression of biomedical micro/nanodevices, thereby propelling this rapidly developing field toward its promising future. Full article
(This article belongs to the Special Issue Nanomaterials for Micro/Nano Devices)
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11 pages, 3431 KiB  
Communication
An Active-Matrix Organic Light-Emitting Diode Pixel Circuit Featuring Mobility Compensation for Portable Applications
by Ching-Lin Fan, Wei-Yu Lin and Shih-Yang Liu
Micromachines 2023, 14(9), 1785; https://doi.org/10.3390/mi14091785 - 18 Sep 2023
Viewed by 1504
Abstract
A 6T1C pixel circuit based on low-temperature polycrystalline oxide (LTPO) technology for portable active-matrix organic light-emitting diode (AMOLED) display applications is proposed in this paper. For superior high-end portable applications including 4K high resolution and high PPI (pixels per inch), the proposed pixel [...] Read more.
A 6T1C pixel circuit based on low-temperature polycrystalline oxide (LTPO) technology for portable active-matrix organic light-emitting diode (AMOLED) display applications is proposed in this paper. For superior high-end portable applications including 4K high resolution and high PPI (pixels per inch), the proposed pixel circuit employs a single storage capacitor and signal sharing switch-control design and provides low-voltage driving and immunity to the IR-drop issue and OLED degradation. Furthermore, the threshold voltage and mobility-compensating capabilities are improved by both compensation mechanisms, which are based on a negative feedback system, and mobility-related compensation parameters. Simulation results reveal that threshold voltage variations of ±0.33 V in the driving thin-film transistors can be well sensed and compensated while the maximum OLED current shift is 4.25%. The maximum variation in OLED currents within all gray levels is only 1.05% with mobility variations of ±30%. As a result, the proposed 6T1C pixel circuit is a good candidate for portable AMOLED display usage. Full article
(This article belongs to the Special Issue Novel 3D Display Technology towards Metaverse)
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9 pages, 4165 KiB  
Communication
A Novel High-Isolation Dual-Polarized Patch Antenna with Two In-Band Transmission Zeros
by Fuwang Li, Yi-Feng Cheng, Gaofeng Wang and Jiang Luo
Micromachines 2023, 14(9), 1784; https://doi.org/10.3390/mi14091784 - 18 Sep 2023
Cited by 12 | Viewed by 1314
Abstract
In this study, we present a novel dual-polarized patch antenna that exhibits high isolation and two in-band transmission zeros (TZs). The design consists of a suspended metal patch, two feeding probes connected to an internal neutralization line (I-NL), and a T-shaped decoupling network [...] Read more.
In this study, we present a novel dual-polarized patch antenna that exhibits high isolation and two in-band transmission zeros (TZs). The design consists of a suspended metal patch, two feeding probes connected to an internal neutralization line (I-NL), and a T-shaped decoupling network (T-DN). The I-NL is responsible for generating the first TZ, and its decoupling principles are explained through an equivalent circuit model. Rigorous design formulas are also derived to aid in the construction of the feeding structure. The T-DN realizes the second TZ, resulting in further improvement of the decoupling bandwidth. Simulation and experimental results show that the proposed antenna has a wide operating bandwidth (2.5–2.7 GHz), high port isolation (>30 dB), and excellent efficiency (>85%). Full article
(This article belongs to the Special Issue Recent Advances in Electromagnetic Devices)
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12 pages, 1763 KiB  
Article
A Mesh Space Mapping Modeling Method with Mesh Deformation for Microwave Components
by Shuxia Yan, Chenglin Li, Mutian Li, Zhimou Li, Xu Wang, Jian Wang and Yaocong Xie
Micromachines 2023, 14(9), 1783; https://doi.org/10.3390/mi14091783 - 17 Sep 2023
Viewed by 1023
Abstract
In this study, a low-cost space mapping (SM) modeling method with mesh deformation is proposed for microwave components. In this approach, the coarse-mesh model with mesh deformation is developed as the coarse model, and the fine-mesh model is simulated as the fine model. [...] Read more.
In this study, a low-cost space mapping (SM) modeling method with mesh deformation is proposed for microwave components. In this approach, the coarse-mesh model with mesh deformation is developed as the coarse model, and the fine-mesh model is simulated as the fine model. The SM technique establishes the mapping relationship between the coarse-mesh model and the fine-mesh model. This approach enables us to combine the computational efficiency of the coarse model with the accuracy of the fine model. The automatic mesh deformation technology is embedded in the coarse model to avoid the discontinuous change in the electromagnetic response. The proposed model consisting of the coarse model and two mapping modules can represent the features of the fine model more accurately, and predict the electromagnetic response of microwave components quickly. The proposed mesh SM modeling technique is applied to the four-pole waveguide filter. The value for the training and test errors in the proposed model is less than 1%, which is lower than that for the ANN models and the existing SM models trained with the same data. Compared with HFSS software, the proposed model can save about 70% CPU time in predicting a set of 100 data. The results show that the proposed method achieves a good modeling accuracy and efficiency with few training data and a low computational cost. Full article
(This article belongs to the Special Issue Recent Advances in Microwave Components and Devices)
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12 pages, 3538 KiB  
Article
Applications of a Novel Tunable Piezoelectric Vibration Energy Harvester
by Sreekumari Raghavan, Rishi Gupta and Loveleen Sharma
Micromachines 2023, 14(9), 1782; https://doi.org/10.3390/mi14091782 - 17 Sep 2023
Cited by 1 | Viewed by 1492
Abstract
Conversion of ambient energy to usable electrical energy is attracting attention from researchers since providing a maintenance-free power source for the sensors is critical in any IoT (Internet of Things)-based system and in SHM (structural health monitoring). Continuous health monitoring of structures is [...] Read more.
Conversion of ambient energy to usable electrical energy is attracting attention from researchers since providing a maintenance-free power source for the sensors is critical in any IoT (Internet of Things)-based system and in SHM (structural health monitoring). Continuous health monitoring of structures is advantageous since the damage can be identified at inception and the necessary action taken. Sensor technology has advanced significantly, and MEMS (microelectromechanical systems)-based low-power sensors are available for incorporating into large structures. Relevant signal conditioning and transmission modules have also evolved, making them power-efficient and miniaturized. Various micro wireless sensor nodes (WSN) have also been developed in recent years that require very little power. This paper describes the applications of a novel tunable piezoelectric vibration energy harvester (PVEH) for providing autonomous power to low-power MEMS sensors for use in IoT and remote SHM. The novel device uses piezoelectric material and an ionic polymer–metal composite (IPMC) and enables electrical tuning of the resonant frequency using a small portion of the power generated. Full article
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35 pages, 3020 KiB  
Article
Thermal Fatigue Effect on the Grain Groove Profile in the Case of Diffusion in Thin Polycrystalline Films of Power Electronic Devices
by Tayssir Hamieh, Ali Ibrahim and Zoubir Khatir
Micromachines 2023, 14(9), 1781; https://doi.org/10.3390/mi14091781 - 17 Sep 2023
Cited by 1 | Viewed by 1239
Abstract
In a previous paper, we solved the partial differential equation of Mullins’ problem in the case of the evaporation–condensation in electronic devices and gave an exact solution relative to the geometric profile of the grain boundary grooving when materials are submitted to thermal [...] Read more.
In a previous paper, we solved the partial differential equation of Mullins’ problem in the case of the evaporation–condensation in electronic devices and gave an exact solution relative to the geometric profile of the grain boundary grooving when materials are submitted to thermal and mechanical solicitation and fatigue effect. In this new research, new modelling of the grain groove profile was proposed and new analytical expressions of the groove profile, the derivative and the groove depth were obtained in the case of diffusion in thin polycrystalline films by the resolution of the fourth differential equation formulated by Mullins that supposed y21. The obtained analytical solution gave more accurate information on the geometric characteristics of the groove that were necessary to study the depth and the width of the groove. These new findings will open a new way to study with more accuracy the problem of the evaporation–condensation combined to the diffusion phenomenon on the material surfaces with the help of the analytical solutions. Full article
(This article belongs to the Special Issue Insulated Gate Bipolar Transistor (IGBT) Modules)
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3 pages, 178 KiB  
Editorial
Editorial for the Special Issue on Network on Chip (NoC) and Reconfigurable Systems
by Abdelkrim Zitouni
Micromachines 2023, 14(9), 1780; https://doi.org/10.3390/mi14091780 - 17 Sep 2023
Viewed by 1042
Abstract
In a multiprocessor System-on-Chip (SoC), efficient communication between the associated processors has to be addressed at all levels of the system design to guarantee global interconnection [...] Full article
(This article belongs to the Special Issue Network on Chip (NoC) and Reconfigurable Systems)
8 pages, 3488 KiB  
Communication
Investigation of the Connection Schemes between Decks in 3D NAND Flash
by Jianquan Jia, Lei Jin, Kaikai You and Anyi Zhu
Micromachines 2023, 14(9), 1779; https://doi.org/10.3390/mi14091779 - 17 Sep 2023
Viewed by 1810
Abstract
Dual-deck stacking technology is an effective solution for solving the contradiction between the demand for increasing storage layers and the challenge of the deep hole etching process in 3D NAND flash. The connection scheme between decks is a key technology for the dual-deck [...] Read more.
Dual-deck stacking technology is an effective solution for solving the contradiction between the demand for increasing storage layers and the challenge of the deep hole etching process in 3D NAND flash. The connection scheme between decks is a key technology for the dual-deck structure. It has become one of the necessary techniques for 3D NAND flash storage density improvement. This article mainly studies the impact of connection schemes between decks on cell reliability. Based on experimental data and simulation analysis, unfavorable effects were found as the gate channeling the breakdown and data retention characteristics of the top cells in the lower deck deteriorated due to the local electric field enhancement in the connection scheme without a poly-plug. This mainly contributed to the structural change of these cells within process impact. They will suffer secondary etching during the upper deck channel etching process due to alignment issues between the upper and lower decks. In another scheme with a poly-plug connection between decks, the saturation current of the channel decreased and the current variation increased. The fundamental cause of the current anomaly is that the Poly-plug has a certain shielding effect on channel inversion and the weak inversion region becomes a bottleneck for the channel current. The increase in variation is due to the shielding effect differences in the different structures of the poly-plug. Therefore, for the connection scheme without a poly-plug, the article proposes to improve device reliability by increasing the oxide thickness between decks and setting the top cells of the lower decks to be virtual cells. For the connection scheme with a poly-plug, the plug‘s N-type doping scheme is proposed to avoid the current dropping anomaly. Full article
(This article belongs to the Special Issue Advances in Emerging Nonvolatile Memory, Volume II)
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17 pages, 7390 KiB  
Article
A Robust Triboelectric Impact Sensor with Carbon Dioxide Precursor-Based Calcium Carbonate Layer for Slap Match Application
by Inkyum Kim, Hyunwoo Cho, Narasimharao Kitchamsetti, Jonghyeon Yun, Jeongmin Lee, Wook Park and Daewon Kim
Micromachines 2023, 14(9), 1778; https://doi.org/10.3390/mi14091778 - 17 Sep 2023
Cited by 3 | Viewed by 1484
Abstract
As an urgent international challenge, the sudden change in climate due to global warming needs to be addressed in the near future. This can be achieved through a reduction in fossil fuel utilization and through carbon sequestration, which reduces the concentration of CO [...] Read more.
As an urgent international challenge, the sudden change in climate due to global warming needs to be addressed in the near future. This can be achieved through a reduction in fossil fuel utilization and through carbon sequestration, which reduces the concentration of CO2 in the atmosphere. In this study, a self-sustainable impact sensor is proposed through implementing a triboelectric nanogenerator with a CaCO3 contact layer fabricated via a CO2 absorption method. The triboelectric polarity of CaCO3 with the location between the polyimide and the paper and the effects of varying the crystal structure are investigated first. The impact sensing characteristics are then confirmed at various input frequencies and under applied forces. Further, the high mechanical strength and strong adherence of CaCO3 on the surface of the device are demonstrated through enhanced durability compared to the unmodified device. For the intended application, the as-fabricated sensor is used to detect the turning state of the paper Ddakji in a slap match game using a supervised learning algorithm based on a support vector machine presenting a high classification accuracy of 95.8%. The robust CaCO3-based triboelectric device can provide an eco-friendly advantage due to its self-powered characteristics for impact sensing and carbon sequestration. Full article
(This article belongs to the Collection Piezoelectric Transducers: Materials, Devices and Applications)
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