Next Issue
Volume 15, November
Previous Issue
Volume 15, September
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
5.2
3.0
Journals
Micromachines
Volume 15
Issue 10
share announcement

Micromachines, Volume 15, Issue 10 (October 2024) – 103 articles

Cover Story (view full-size image): The cover depicts two DNA-like helical structures, one blue and one red, held in two hands, symbolizing their distinct chiralities. The DNA molecules are illuminated by circularly polarized light with different handedness. The bright blue and red highlight the different chiralities of light and the interactions between light and chiral objects. Under the influence of chiral light forces and fluid dynamics, the two DAN molecules eventually separate, expressing the utilization of optical forces generated by the interaction of chiral light and matter to manipulate micro-/nanoparticles. Optical forces on chiral particles find numerous applications in the biomedical, chemical and physical sciences. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
17 pages, 7627 KiB  
Article
Research on Optimization of Height Difference of a Precision Horizontal Machining Center
by Lin Han, Zhenyun Zhang, Xueguang Tian, Houjun Qi, Fucong Liu and Yang Qi
Micromachines 2024, 15(10), 1279; https://doi.org/10.3390/mi15101279 - 21 Oct 2024
Viewed by 610
Abstract
This work proposes a methodology to determine the height difference of the guideways of machine tools where two guideways are not placed on the same horizontal plane. Firstly, a rigid–flexible coupling system consisting of a moving rigid mass and an elastic overhanging beam [...] Read more.
This work proposes a methodology to determine the height difference of the guideways of machine tools where two guideways are not placed on the same horizontal plane. Firstly, a rigid–flexible coupling system consisting of a moving rigid mass and an elastic overhanging beam is presented as an equivalent mechanical model of a column and a spindle box. Then, the relationship between the deviation of a reference point and the height difference or the spindle box’s stroke is modeled. Next, the natural frequency and mode shape function of the overhanging beam, and the frequency response functions of the coupling system, are derived. The results indicate that there always exists an optimal height difference minimizing the relative deflection over the stroke of the moving part, and the optimal value depends on the loads in two directions and the stroke of the moving part. Similarly, there is also an optimal choice maximizing the first-order resonant frequency of the coupling system; however, the optimal solutions for both static and dynamic cases are not the same. This work provides beneficial instruction for choosing the height difference of machine tools with two guideways on a bed that are not on the same plane. Full article
►▼ Show Figures

Figure 1

14 pages, 6993 KiB  
Article
Strain-Induced Frequency Splitting in PT Symmetric Coupled Silicon Resonators
by Lifeng Wang, Shangyang Zhang and Qunce Yuan
Micromachines 2024, 15(10), 1278; https://doi.org/10.3390/mi15101278 - 21 Oct 2024
Viewed by 609
Abstract
When two resonators of coupled silicon resonators are identical and the gain on one side is equal to the loss on the other side, a parity-time (PT) symmetric-coupled silicon resonator is formed. As non-Hermitian systems, the PT-symmetric systems have exhibited many special properties [...] Read more.
When two resonators of coupled silicon resonators are identical and the gain on one side is equal to the loss on the other side, a parity-time (PT) symmetric-coupled silicon resonator is formed. As non-Hermitian systems, the PT-symmetric systems have exhibited many special properties and interesting phenomena. This paper proposes the strain-induced frequency splitting in PT symmetry-coupled silicon resonators. The frequency splitting of the PT system caused by strain perturbations is derived and simulated. Theory and simulation both indicate that the PT system is more sensitive to strain perturbation near the exceptional point (EP) point. Then, a feedback circuit is designed to achieve the negative damping required for PT symmetry. Based on a simple silicon-on-insulator (SOI) process, the silicon resonator chip is successfully fabricated. After that, the PT-symmetric-coupled silicon resonators are successfully constructed, and the frequency splitting phenomenon caused by strain is observed experimentally. Full article
(This article belongs to the Special Issue MEMS/NEMS Devices and Applications, 2nd Edition)
►▼ Show Figures

Figure 1

16 pages, 6173 KiB  
Article
Optimal Control of FSBB Converter with Aquila Optimizer-Based PID Controller
by Luoyao Ren, Dazhi Wang and Yupeng Zhang
Micromachines 2024, 15(10), 1277; https://doi.org/10.3390/mi15101277 - 21 Oct 2024
Viewed by 634
Abstract
This paper presents a new methodology for determining the optimal coefficients of a PID controller for a four-switch buck–boost (FSBB) converter. The main objective of this research is to improve the performance of FSBB converters by fine-tuning the parameters of the PID controller [...] Read more.
This paper presents a new methodology for determining the optimal coefficients of a PID controller for a four-switch buck–boost (FSBB) converter. The main objective of this research is to improve the performance of FSBB converters by fine-tuning the parameters of the PID controller using the newly developed Aquila Optimizer (AO). PID controllers are widely recognized for their simple yet effective control in FSBB converters. However, to further improve the efficiency and reliability of the control system, the PID control parameters must be optimized. In this context, the application of the AO algorithm proves to be a significant advance. By optimizing the PID coefficients, the dynamic responsiveness of the system can be improved, thus reducing the response time. In addition, the robustness of the control system is enhanced, which is essential to ensure stable and reliable operation under varying conditions. The use of AOs plays a key role in maintaining system stability and ensuring the proper operation of the control system even under challenging conditions. In order to demonstrate the effectiveness and potential of the proposed method, the performance of the AO-optimized PID controller was compared with that of PID controllers tuned by other optimization algorithms in the same test environment. The results show that the AO outperforms the other optimization algorithms in terms of dynamic response and robustness, thus validating the efficiency and correctness of the proposed method. This work highlights the advantages of using the Aquila Optimizer in the PID tuning of FSBB converters, providing a promising solution for improving system performance. Full article
►▼ Show Figures

Figure 1

17 pages, 5166 KiB  
Article
Integration of Metrology in Grinding and Polishing Processes for Rotationally Symmetrical Aspherical Surfaces with Optimized Material Removal Functions
by Ravi Pratap Singh and Yaolong Chen
Micromachines 2024, 15(10), 1276; https://doi.org/10.3390/mi15101276 - 21 Oct 2024
Viewed by 612
Abstract
Aspherical surfaces, with their varying curvature, minimize aberrations and enhance clarity, making them essential in optics, aerospace, medical devices, and telecommunications. However, manufacturing these surfaces is challenging because of systematic errors in CNC equipment, tool wear, measurement inaccuracies, and environmental disturbances. These issues [...] Read more.
Aspherical surfaces, with their varying curvature, minimize aberrations and enhance clarity, making them essential in optics, aerospace, medical devices, and telecommunications. However, manufacturing these surfaces is challenging because of systematic errors in CNC equipment, tool wear, measurement inaccuracies, and environmental disturbances. These issues necessitate precise error compensation to achieve the desired surface shape. Traditional methods for spherical optics are inadequate for aspherical components, making accurate surface shape error detection and compensation crucial. This study integrates advanced metrology with optimized material removal functions in the grinding and polishing processes. By combining numerical control technology, computer technology, and data analysis, we developed CAM software (version 1) tailored for aspherical surfaces. This software uses a compensation correction algorithm to process error data and generate NC programs for machining. Our approach automates and digitizes the grinding and polishing process, improving efficiency and surface accuracy. This advancement enables high-precision mass production of rotationally symmetrical aspherical optical components, addressing existing manufacturing challenges and enhancing optical system performance. Full article
(This article belongs to the Special Issue Recent Advances in Micro/Nano-Fabrication)
►▼ Show Figures

Figure 1

15 pages, 7954 KiB  
Article
Investigation on the Machinability of Polycrystalline ZnS by Micro-Laser-Assisted Diamond Cutting
by Haoqi Luo, Xue Wang, Lin Qin, Hongxin Zhao, Deqing Zhu, Shanyi Ma, Jianguo Zhang and Junfeng Xiao
Micromachines 2024, 15(10), 1275; https://doi.org/10.3390/mi15101275 - 21 Oct 2024
Viewed by 697
Abstract
Polycrystalline ZnS is a typical infrared optical material. It is widely used in advanced optical systems due to its excellent optical properties. The machining accuracy of polycrystalline ZnS optical elements must satisfy the requirements of high-performance system development. However, the soft and brittle [...] Read more.
Polycrystalline ZnS is a typical infrared optical material. It is widely used in advanced optical systems due to its excellent optical properties. The machining accuracy of polycrystalline ZnS optical elements must satisfy the requirements of high-performance system development. However, the soft and brittle nature of the material poses a challenge for high-quality and efficient machining. In recent years, in situ laser-assisted diamond cutting has been proven to be an effective method for ultra-precision cutting of brittle materials. In this study, the mechanism of in situ laser-assisted cutting on ultra-precision cutting machinability enhancement of ZnS was investigated. Firstly, the physical properties of ZnS were characterized by high-temperature nanoindentation experiments. The result revealed an increase in ductile machinability of ZnS due to plastic deformation and a decrease in microhardness and Young’s modulus at high temperatures. It provided a fundamental theory for the ductile–brittle transition of ZnS. Subsequently, a series of diamond-cutting experiments were carried out to study the removal mechanism of ZnS during in situ laser-assisted cutting. It was found that the mass damage initiation depth groove generated by in situ laser-assisted cutting increased by 57.99% compared to the groove generated by ordinary cutting. It was found that micron-sized pits were suppressed under in situ laser-assisted cutting. The main damage form of HIP-ZnS was changed from flake spalling and pits to radial cleavage cracks. Additionally, the laser can suppress the removal mode difference of different grain crystallographic and ensure the ductile region processing. Finally, planning cutting experiments were carried out to verify that a smooth and uniform surface with Sa of 3.607 nm was achieved at a laser power of 20 W, which was 73.58% better than normal cutting. The main components of roughness were grain boundary steps and submicron pit. This study provides a promising method for ultra-precision cutting of ZnS. Full article
(This article belongs to the Special Issue Recent Advances in Micro/Nano-Fabrication)
►▼ Show Figures

Figure 1

29 pages, 4587 KiB  
Review
A Thorough Review of Emerging Technologies in Micro- and Nanochannel Fabrication: Limitations, Applications, and Comparison
by Koosha Karimi, Ali Fardoost, Nikhil Mhatre, Jay Rajan, David Boisvert and Mehdi Javanmard
Micromachines 2024, 15(10), 1274; https://doi.org/10.3390/mi15101274 - 21 Oct 2024
Viewed by 1503
Abstract
In recent years, the field of micro- and nanochannel fabrication has seen significant advancements driven by the need for precision in biomedical, environmental, and industrial applications. This review provides a comprehensive analysis of emerging fabrication technologies, including photolithography, soft lithography, 3D printing, electron-beam [...] Read more.
In recent years, the field of micro- and nanochannel fabrication has seen significant advancements driven by the need for precision in biomedical, environmental, and industrial applications. This review provides a comprehensive analysis of emerging fabrication technologies, including photolithography, soft lithography, 3D printing, electron-beam lithography (EBL), wet/dry etching, injection molding, focused ion beam (FIB) milling, laser micromachining, and micro-milling. Each of these methods offers unique advantages in terms of scalability, precision, and cost-effectiveness, enabling the creation of highly customized micro- and nanochannel structures. Challenges related to scalability, resolution, and the high cost of traditional techniques are addressed through innovations such as deep reactive ion etching (DRIE) and multipass micro-milling. This paper also explores the application potential of these technologies in areas such as lab-on-a-chip devices, biomedical diagnostics, and energy-efficient cooling systems. With continued research and technological refinement, these methods are poised to significantly impact the future of microfluidic and nanofluidic systems. Full article
(This article belongs to the Special Issue Advances in Micro and Nano Manufacturing: Process Modeling and Applications, 3rd Edition)
►▼ Show Figures

Figure 1

10 pages, 1650 KiB  
Article
A Sub-1 ppm/°C Reference Voltage Source with a Wide Input Range
by Yuchi Xiao, Chunlai Wang, Hongyang Hou and Weihua Han
Micromachines 2024, 15(10), 1273; https://doi.org/10.3390/mi15101273 - 21 Oct 2024
Viewed by 606
Abstract
With the continuous advancement of electronic technology, the application of high-voltage integrated circuits is becoming increasingly prevalent in fields such as power systems, medical devices, and industrial automation. The reference circuit within high-voltage integrated circuits must not only exhibit insensitivity to temperature variations [...] Read more.
With the continuous advancement of electronic technology, the application of high-voltage integrated circuits is becoming increasingly prevalent in fields such as power systems, medical devices, and industrial automation. The reference circuit within high-voltage integrated circuits must not only exhibit insensitivity to temperature variations but also maintain stability across a broad voltage supply. This paper presents a bandgap reference (BGR) source capable of operating over a wide input range. This BGR employs a high-order curvature compensation method to eliminate nonlinear voltage terms, resulting in minimal temperature drift. The circuit achieves an impressive temperature coefficient (TC) of 0.88 ppm/°C over a temperature range from −40 °C to 130 °C. To ensure stable operation within a 4–40 V range, the design incorporates a pre-regulation circuit that stabilizes the supply voltage of the BGR core at a fixed value, thereby enhancing the ability to withstand variations in power supply voltage. Full article
(This article belongs to the Special Issue Latest Advancements in Semiconductor Materials, Devices, and Systems)
►▼ Show Figures

Figure 1

16 pages, 4542 KiB  
Article
Miniaturized Pathogen Detection System Using Magnetic Nanoparticles and Microfluidics Technology
by Benjamin Garlan, Amine Rabehi, Kieu Ngo, Sophie Neveu, Reza Askari Moghadam and Hamid Kokabi
Micromachines 2024, 15(10), 1272; https://doi.org/10.3390/mi15101272 - 20 Oct 2024
Viewed by 765
Abstract
Rapid detection of a biological agent is essential to anticipate a threat to the protection of biodiversity and ecosystems. Our goal is to miniaturize a magnetic pathogen detection system in order to fabricate an efficient and portable system. The detection device is based [...] Read more.
Rapid detection of a biological agent is essential to anticipate a threat to the protection of biodiversity and ecosystems. Our goal is to miniaturize a magnetic pathogen detection system in order to fabricate an efficient and portable system. The detection device is based on flat, multilayer coils associated with microfluidic structures to detect magnetic nanoparticles linked to pathogen agents. One type of immunological diagnosis is based on the measurement of the magnetic sensitivity of magnetic nanoparticles (MNPs), which are markers connected to pathogens. This method of analysis involves the coupling of antibodies or antigen proteins with MNPs. Among the available magnetic techniques, the frequency mixing method has a definite advantage by making it possible to quantify MNPs. An external magnetic field composed of a low- and a high-frequency field is applied to the sample reservoir. Then, the response signal is measured and analyzed. In this paper, magnetic microcoils are implemented on a multilayer Printed Circuit Board (PCB), and a microfluidics microstructure is designed in connection with the planar coils. Simulation software, COMSOL version 5.3, provides an analytical perspective to choose the number of turns in magnetic coils and to understand the effects of changing the shape and dimensions of the microfluidics microstructure. Full article
(This article belongs to the Special Issue Recent Advances in Lab-on-a-Chip and Their Biomedical Applications)
►▼ Show Figures

Figure 1

14 pages, 4403 KiB  
Article
Temperature Compensation Method for Tunnel Magnetoresistance Micro-Magnetic Sensors Through Reference Magnetic Field
by Tao Kuai, Qingfa Du, Jiafei Hu, Shilong Shi, Peisen Li, Dixiang Chen and Mengchun Pan
Micromachines 2024, 15(10), 1271; https://doi.org/10.3390/mi15101271 - 20 Oct 2024
Viewed by 606
Abstract
The sensitivity of Tunnel Magnetoresistance (TMR) sensors is characterized by significant temperature drift and poor sensitivity drift repeatability, which severely impairs measurement accuracy. Conventional temperature compensation techniques are often hindered by low compensation precision, inadequate real-time performance, and an inability to effectively address [...] Read more.
The sensitivity of Tunnel Magnetoresistance (TMR) sensors is characterized by significant temperature drift and poor sensitivity drift repeatability, which severely impairs measurement accuracy. Conventional temperature compensation techniques are often hindered by low compensation precision, inadequate real-time performance, and an inability to effectively address the issue of poor repeatability in temperature drift characteristics. To overcome these challenges, this paper introduces a novel method for suppressing temperature drift in TMR sensors. In this method, an alternating reference magnetic field is applied to TMR sensors, and the output amplitude at the frequency of the reference magnetic field is calculated to compensate the sensitivity temperature drift in real time. Temperature characteristic tests were conducted in a non-magnetic temperature test chamber, and the results revealed that the proposed method significantly reduced the TMR sensitivity drift coefficient from 985.39 ppm/°C to 59.08 ppm/°C. Additionally, the repeatability of sensitivity temperature characteristic curves was enhanced, with a reduction in root mean square error from 0.84 to 0.21. This approach effectively mitigates temperature-induced sensitivity drift without necessitating the use of a temperature sensor, and has the advantages of real-time performance and repeatability, providing a new approach for the high-precision temperature drift suppression of TMR. Full article
►▼ Show Figures

Figure 1

19 pages, 1700 KiB  
Article
Transport in a Two-Channel Nanotransistor Device with Lateral Resonant Tunneling
by Ulrich Wulf, Amanda Teodora Preda and George Alexandru Nemnes
Micromachines 2024, 15(10), 1270; https://doi.org/10.3390/mi15101270 - 19 Oct 2024
Viewed by 607
Abstract
We study field effect nanotransistor devices in the Si/SiO2 material system which are based on lateral resonant tunneling between two parallel conduction channels. After introducing a simple piecewise linear potential model, we calculate the quantum transport properties in the R-matrix approach. In [...] Read more.
We study field effect nanotransistor devices in the Si/SiO2 material system which are based on lateral resonant tunneling between two parallel conduction channels. After introducing a simple piecewise linear potential model, we calculate the quantum transport properties in the R-matrix approach. In the transfer characteristics, we find a narrow resonant tunneling peak around zero control voltage. Such a narrow resonant tunneling peak allows one to switch the drain current with small control voltages, thus opening the way to low-energy applications. In contrast to similar double electron layer tunneling transistors that have been studied previously in III-V material systems with much larger channel lengths, the resonant tunneling peak in the drain current is found to persist at room temperature. We employ the R-matrix method in an effective approximation for planar systems and compare the analytical results with full numerical calculations. This provides a basic understanding of the inner processes pertaining to lateral tunneling transport. Full article
►▼ Show Figures

Figure 1

13 pages, 16639 KiB  
Article
Multi-Wavelength Narrow-Spacing Laser Frequency Stabilization Technology Based on Fabry-Perot Etalon
by Ju Wang, Ye Gao, Jinlong Yu, Hao Luo, Xuemin Su, Shiyu Zhang, Ruize Zhang and Chuang Ma
Micromachines 2024, 15(10), 1269; https://doi.org/10.3390/mi15101269 - 18 Oct 2024
Viewed by 638
Abstract
Classical frequency-stabilized lasers have achieved high-frequency stability and reproducibility; however, their extensive wavelength spacing limits their utility in various scenarios. This study introduces a novel frequency-stabilized laser scheme that integrates a Fabry-Perot etalon (FPE) with digital control technology and wavelength modulation techniques. The [...] Read more.
Classical frequency-stabilized lasers have achieved high-frequency stability and reproducibility; however, their extensive wavelength spacing limits their utility in various scenarios. This study introduces a novel frequency-stabilized laser scheme that integrates a Fabry-Perot etalon (FPE) with digital control technology and wavelength modulation techniques. The FPE, characterized by multiple transmission peaks at minimal frequency intervals, provides stable frequency references for different lasers, thereby enhancing the system’s flexibility and adaptability. An error signal is derived from the first-order differentiation of the FPE’s transmission curve. A 180° phase difference was observed in the feedback output signal when the laser’s central frequency diverged from the reference, determining that the direction of the frequency control was accordingly determined.Employing feedback control, the laser’s output frequency is stabilized at the transmission peak frequency of the FPE. Experimental results demonstrate that this stabilization scheme effectively locks the laser’s output wavelength to different transmission peak frequencies of the FPE, achieving 25 GHz wavelength spacing. The frequency stability is improved by two orders of magnitude on a second-level timescale, maintained within hundreds of kHz, equating to a frequency stability level of 10−10. Full article
(This article belongs to the Special Issue Integrated Photonics and Optoelectronics, 2nd Edition)
►▼ Show Figures

Figure 1

2 pages, 152 KiB  
Editorial
Editorial for the Special Issue on Nanomaterials Photonics
by Raul Rangel-Rojo, Luciana R. P. Kassab and Tiziana Cesca
Micromachines 2024, 15(10), 1268; https://doi.org/10.3390/mi15101268 - 18 Oct 2024
Viewed by 432
Abstract
Back in 1959, Richard Feynman, in his famous lecture, stated that “There is plenty of room at the bottom”, which made us aware of the possibilities of nanotechnology, i [...] Full article
(This article belongs to the Special Issue Nanomaterials Photonics)
20 pages, 4707 KiB  
Review
Optical Forces on Chiral Particles: Science and Applications
by Weicheng Yi, Haiyang Huang, Chengxing Lai, Tao He, Zhanshan Wang, Xinhua Dai, Yuzhi Shi and Xinbin Cheng
Micromachines 2024, 15(10), 1267; https://doi.org/10.3390/mi15101267 - 17 Oct 2024
Viewed by 1030
Abstract
Chiral particles have attracted considerable attention due to their distinctive interactions with light, which enable a variety of cutting-edge applications. This review presents a comprehensive analysis of the optical forces acting on chiral particles, categorizing them into gradient force, radiation pressure, optical lateral [...] Read more.
Chiral particles have attracted considerable attention due to their distinctive interactions with light, which enable a variety of cutting-edge applications. This review presents a comprehensive analysis of the optical forces acting on chiral particles, categorizing them into gradient force, radiation pressure, optical lateral force, pulling force, and optical force on coupled chiral particles. We thoroughly overview the fundamental physical mechanisms underlying these forces, supported by theoretical models and experimental evidence. Additionally, we discuss the practical implications of these optical forces, highlighting their potential applications in optical manipulation, particle sorting, chiral sensing, and detection. This review aims to offer a thorough understanding of the intricate interplay between chiral particles and optical forces, laying the groundwork for future advancements in nanotechnology and photonics. Full article
(This article belongs to the Special Issue The 15th Anniversary of Micromachines)
►▼ Show Figures

Figure 1

23 pages, 10697 KiB  
Article
Mechanical Property of Thermoplastic Polyurethane Vascular Stents Fabricated by Fused Filament Fabrication
by Yun Zhai, Zezhi Sun, Tie Zhang, Changchun Zhou and Xiangpeng Kong
Micromachines 2024, 15(10), 1266; https://doi.org/10.3390/mi15101266 - 17 Oct 2024
Viewed by 720
Abstract
Vascular stents have many applications in treating arterial stenosis and other vascular-related diseases. The ideal vascular stent for clinical application should have radial support and axial bending mechanical properties that meet the requirements of vascular deformation coordination. The materials used for vascular stents [...] Read more.
Vascular stents have many applications in treating arterial stenosis and other vascular-related diseases. The ideal vascular stent for clinical application should have radial support and axial bending mechanical properties that meet the requirements of vascular deformation coordination. The materials used for vascular stents implanted in the human body should have corresponding biocompatibility to ensure that the stents do not cause coagulation, hemolysis, and other reactions in the blood. This study fabricated four types of vascular stents, including inner hexagon, arrowhead, quadrilateral, and outer hexagonal, using fused filament fabrication technology and thermoplastic polyurethane (TPU) as materials. By evaluating the effects of edge width and wall thickness on the radial support and axial bending performance, it was found that the inner hexagonal stent exhibited the best radial support and axial bending performance under the same conditions. The design and fabrication of vascular stents based on 3D printing technology have promising application prospects in personalized customized vascular repair therapy. Full article
(This article belongs to the Special Issue Microfluidics and 3D Printing for Biomedical Applications)
►▼ Show Figures

Figure 1

17 pages, 2167 KiB  
Article
LDF-BNN: A Real-Time and High-Accuracy Binary Neural Network Accelerator Based on the Improved BNext
by Rui Wan, Rui Cen, Dezheng Zhang and Dong Wang
Micromachines 2024, 15(10), 1265; https://doi.org/10.3390/mi15101265 - 17 Oct 2024
Viewed by 555
Abstract
Significant progress has been made in industrial defect detection due to the powerful feature extraction capabilities of deep neural networks (DNNs). However, the high computational cost and memory requirement of DNNs pose a great challenge to the deployment of industrial edge-side devices. Although [...] Read more.
Significant progress has been made in industrial defect detection due to the powerful feature extraction capabilities of deep neural networks (DNNs). However, the high computational cost and memory requirement of DNNs pose a great challenge to the deployment of industrial edge-side devices. Although traditional binary neural networks (BNNs) have the advantages of small storage space requirements, high parallel computing capability, and low power consumption, the problem of significant accuracy degradation cannot be ignored. To tackle these challenges, this paper constructs a BNN with layered data fusion mechanism (LDF-BNN) based on BNext. By introducing the above mechanism, it strives to minimize the bandwidth pressure while reducing the loss of accuracy. Furthermore, we have designed an efficient hardware accelerator architecture based on this mechanism, enhancing the performance of high-accuracy BNN models with complex network structures. Additionally, the introduction of multi-storage parallelism alleviates the limitations imposed by the internal transfer rate, thus improving the overall computational efficiency. The experimental results show that our proposed LDF-BNN outperforms other methods in the comprehensive comparison, achieving a high accuracy of 72.23%, an image processing rate of 72.6 frames per second (FPS), and 1826 giga operations per second (GOPs) on the ImageNet dataset. Meanwhile, LDF-BNN can also be well applied to defect detection dataset Mixed WM-38, achieving a high accuracy of 98.70%. Full article
►▼ Show Figures

Figure 1

26 pages, 62591 KiB  
Article
Thermal Bending Simulation and Experimental Study of 3D Ultra-Thin Glass Components for Smartwatches
by Shunchang Hu, Peiyan Sun, Zhen Zhang, Guojun Zhang and Wuyi Ming
Micromachines 2024, 15(10), 1264; https://doi.org/10.3390/mi15101264 - 17 Oct 2024
Viewed by 721
Abstract
The heating system is an essential component of the glass molding process. It is responsible for heating the glass to an appropriate temperature, allowing it to soften and be easily molded. However, the energy consumption of the heating system becomes particularly significant in [...] Read more.
The heating system is an essential component of the glass molding process. It is responsible for heating the glass to an appropriate temperature, allowing it to soften and be easily molded. However, the energy consumption of the heating system becomes particularly significant in large-scale production. This study utilized G-11 glass for the simulation analysis and developed a finite element model for the thermal conduction of a 3D ultra-thin glass molding system, as well as a thermal bending model for smartwatches. Using finite element software, the heat transfer between the mold and the glass was modeled, and the temperature distribution and thermal stress under various processing conditions were predicted. The findings of the simulation, when subjected to a numerical analysis, showed that heating rate techniques significantly affect energy consumption. This study devised a total of four heating strategies. Upon comparison, optimizing with heating strategy 4, which applies an initial heating rate of 35 mJ/(mm2·s) during the initial phase (0 to 60 s) and subsequently escalates to 45 mJ/(mm2·s) during the second phase (60 to 160 s), resulted in a reduction of 4.396% in the system’s thermal output and a notable decrease of 7.875% in the heating duration, respectively. Furthermore, a single-factor research method was employed to study the forming process parameters. By comparing the numerical simulation results, it was found that within the temperature range of 615–625 °C, a molding pressure of 25–35 MPa, a heating rate of 1.5–2.5 °C/s, a cooling rate of 0.5–1 °C/s, and a pulse pressure of 45–55 Hz, the influence on residual stress and shape deviation in the glass was minimal. The relative error range was within the 20% acceptable limit, according to the experimental validation, which offered crucial direction and ideas for process development. Full article
(This article belongs to the Special Issue Hybrid Energy Field Manufacturing Technology for Difficult-to-Machine Materials)
►▼ Show Figures

Figure 1

21 pages, 5395 KiB  
Article
Air Leakages at Microvalves: Pressure Decay Measurements and Extended Continuum Modelling of Knudsen Flows
by Daniel Anheuer, Johannes Schwarz, Patrick Debera, Klaus Heinrich, Christoph Kutter and Martin Richter
Micromachines 2024, 15(10), 1263; https://doi.org/10.3390/mi15101263 - 16 Oct 2024
Viewed by 625
Abstract
To improve the performance of valves in relation to the leakage rate, a comprehensive evaluation of the valve characteristics and behavior during pressure exposure is important. Often, these low gas flow rates below 0.1 cm3/min cannot be accurately measured with conventional [...] Read more.
To improve the performance of valves in relation to the leakage rate, a comprehensive evaluation of the valve characteristics and behavior during pressure exposure is important. Often, these low gas flow rates below 0.1 cm3/min cannot be accurately measured with conventional flow sensors. This paper presents a small and low-cost test rig for measuring gas leakage rates accurately, even far below 0.1 cm3/min, with the pressure decay method. These leakage flows are substantiated with a flow model, where we demonstrate the feasibility of modeling those gas flows with an extended Navier–Stokes framework to obtain more accurate theoretical predictions. As expected, the comparison to the experimental results proves that the classical Navier–Stokes system is unsuitable for modeling Knudsen flows. Hence, self-diffusion of gas, a wall-slip boundary condition, and an effective mean free path model were introduced in a physically evident manner. In terms of the calculated mass flow, while self-diffusion and slip boundary conditions explain deviations from the classical Navier–Stokes equation for Knudsen numbers already smaller than 1, the effective mean free path model has an effect, especially when Kn > 1. For simplified conditions, an analytical solution was presented and compared to the results of an OpenFOAM CFD-solver for flow rates through more complex gap-flow geometries of the flap valve. Hereby, acceptable deviations between 10% and 20% were observed. A comparison with measurement results was carried out. The reproducibility of the measurement method was verified by comparing multiple measurements of one silicon microvalve sample to a state-of-the-art flow sensor. Three geometrically similar passive silicon microvalves were measured with air overpressure decreasing from 15 kPa relative to atmospheric pressure. Maximum gas volume flowing in a blocking direction of 1–26 µL/min with high reproducibility and marginal noise were observed. Full article
►▼ Show Figures

Figure 1

13 pages, 6414 KiB  
Article
A Net Shape Profile Extraction Approach for Exploring the Forming Appearance of Inclined Thick-Walled Structures by Wire Arc Additive Manufacturing
by Yexing Zheng, Yongzhe Li, Yijun Zhou, Xiaoyu Wang and Guangjun Zhang
Micromachines 2024, 15(10), 1262; https://doi.org/10.3390/mi15101262 - 16 Oct 2024
Viewed by 573
Abstract
Wire arc additive manufacturing (WAAM) offers a viable solution for fabricating large-scale metallic parts, which contain various forms of inclined thick-walled structure. Due to the variety of heat dissipation conditions at different positions, the inclined thick-walled structure is a major challenge in fabrication [...] Read more.
Wire arc additive manufacturing (WAAM) offers a viable solution for fabricating large-scale metallic parts, which contain various forms of inclined thick-walled structure. Due to the variety of heat dissipation conditions at different positions, the inclined thick-walled structure is a major challenge in fabrication that may produce collapses and defects. However, there is a lack of effective sensing method for acquiring the forming appearance of individual beads in the structure. This paper proposes a novel approach for extracting individual bead profiles during the WAAM process. The approach utilizes a structured-laser sensor to capture the morphology of the surface before and after deposition, thereby enabling an accurate acquisition of the bead profile by integrating the laser stripes. Utilizing the proposed approach, the research investigated the forming mechanism of beads in inclined thick-walled components that were fabricated by various deposition parameters. The width of the overlapping area at the overhanging feature decreased as the layer number increased, while the height of the same area increased. The height of the overlapping area in each layer increased with an increase in deposition current and decreased when the deposition speed was increased. These phenomena suggest that the heat input is a major factor that influences the formation of the overhanging feature. Both the deposition current and deposition velocity influence heat input, and thereby have an effect in enhancing the geometrical accuracy of an overhanging feature. The experimental results indicate that the proposed approach facilitates morphology change investigation, providing a sufficient reference for optimizing deposition parameters. Full article
(This article belongs to the Special Issue Advanced Manufacturing Technology and Systems, 3rd Edition)
►▼ Show Figures

Figure 1

16 pages, 21094 KiB  
Article
Development of a Meander-Coil-Type Dual Magnetic Group Circumferential Magnetostrictive Guided Wave Transducer for Detecting Small Defects Hidden behind Support Structures
by Jinjie Zhou, Hang Zhang, Yuepeng Chen and Jitang Zhang
Micromachines 2024, 15(10), 1261; https://doi.org/10.3390/mi15101261 - 15 Oct 2024
Viewed by 634
Abstract
In order to solve the problem that small defects hidden behind pipeline support parts are difficult to detect effectively in small spaces, such as offshore oil platforms, a meander-coil-type dual magnetic group circumferential magnetostrictive guided wave transducer is developed in this paper. The [...] Read more.
In order to solve the problem that small defects hidden behind pipeline support parts are difficult to detect effectively in small spaces, such as offshore oil platforms, a meander-coil-type dual magnetic group circumferential magnetostrictive guided wave transducer is developed in this paper. The transducer, which consists of a coil, two sets of permanent magnets, and a magnetostrictive patch, can excite a high-frequency circumferential shear horizontal (CSH) guided wave. The energy conversion efficiency of the MPT is optimized through magnetic field simulation and experiment, and the amplitude of the defect signal is enhanced 1.9 times. The experimental results show that the MPT developed in this paper can effectively excite and receive CSH2 mode guided waves with a center frequency of 1.6 MHz. Compared with the traditional PPM EMAT transducer, the excitation energy of the transducer is significantly enhanced, and the defects of the 2 mm round hole at the back of the support can be effectively detected. Full article
(This article belongs to the Special Issue Acoustic Transducers and Their Applications, 2nd Edition)
►▼ Show Figures

Figure 1

11 pages, 4237 KiB  
Article
Optimized Driving Scheme for Three-Color Electrophoretic Displays Based on the Elimination of Red Ghost Images
by Mouhua Jiang, Zichuan Yi, Jiashuai Wang, Feng Li, Boyuan Lai, Liangyu Li, Li Wang, Liming Liu, Feng Chi and Guofu Zhou
Micromachines 2024, 15(10), 1260; https://doi.org/10.3390/mi15101260 - 15 Oct 2024
Viewed by 605
Abstract
Three-color electrophoretic display (EPD) is emerging as a display technology due to its extremely low energy consumption and excellent reflective properties. However, in the process of black and white color image transition, due to the different driving characteristics of red particles, the particles [...] Read more.
Three-color electrophoretic display (EPD) is emerging as a display technology due to its extremely low energy consumption and excellent reflective properties. However, in the process of black and white color image transition, due to the different driving characteristics of red particles, the particles within the three-color EPD cannot be ideally driven to the target position, resulting in the appearance of a red ghost image. For this reason, this study utilized the COMSOL 5.6 finite element simulation method to construct a three-dimensional simulation model to explore the motion characteristics of electrophoretic particles, and then proposed a new driving scheme. The driving scheme aimed to drive red particles to the target position and eliminate the red ghost image by optimizing the pixel erasing stage and employing a high-frequency oscillating voltage. The final experimental results showed that after adopting the proposed driving scheme, the red ghost image was reduced by 8.57% and the brightness of the white color image was increased by 17.50%. This method effectively improved the display performance of three-color EPDs and contributed to the better application of three-color EPDs in the field of high-reflectivity and high-quality display. Full article
(This article belongs to the Special Issue Photonic and Optoelectronic Devices and Systems, Second Edition)
►▼ Show Figures

Figure 1

21 pages, 4774 KiB  
Review
Evolution of Tribotronics: From Fundamental Concepts to Potential Uses
by Yue He, Jia Tian, Fangpei Li, Wenbo Peng and Yongning He
Micromachines 2024, 15(10), 1259; https://doi.org/10.3390/mi15101259 - 15 Oct 2024
Viewed by 839
Abstract
The intelligent sensing network is one of the key components in the construction of the Internet of Things, and the power supply technology of sensor communication nodes needs to be solved urgently. As a new field combining tribo-potential with semiconductor devices, tribotronics, based [...] Read more.
The intelligent sensing network is one of the key components in the construction of the Internet of Things, and the power supply technology of sensor communication nodes needs to be solved urgently. As a new field combining tribo-potential with semiconductor devices, tribotronics, based on the contact electrification (CE) effect, realizes direct interaction between the external environment and semiconductor devices by combining triboelectric nanogenerator (TENG) and field-effect transistor (FET), further expanding the application prospects of micro/nano energy. In this paper, the research progress of tribotronics is systematically reviewed. Firstly, the mechanism of the CE effect and the working principles of TENG are introduced. Secondly, the regulation theory of tribo-potential on carrier transportation in semiconductor devices and the research status of tribotronic transistors are summarized. Subsequently, the applications of tribotronics in logic circuits and memory devices, smart sensors, and artificial synapses in recent years are demonstrated. Finally, the challenges and development prospects of tribotronics in the future are projected. Full article
(This article belongs to the Special Issue Triboelectric Nanogenerators: From Fundamental Research to Applications)
►▼ Show Figures

Figure 1

13 pages, 3035 KiB  
Article
Study of Weight Quantization Associations over a Weight Range for Application in Memristor Devices
by Yerim Kim, Hee Yeon Noh, Gyogwon Koo, Hyunki Lee, Sanghan Lee, Rock-Hyun Choi, Shinbuhm Lee, Myoung-Jae Lee and Hyeon-Jun Lee
Micromachines 2024, 15(10), 1258; https://doi.org/10.3390/mi15101258 - 15 Oct 2024
Viewed by 679
Abstract
The development of hardware-based cognitive computing systems critically hinges upon the integration of memristor devices capable of versatile weight expression across a spectrum of resistance levels while preserving consistent electrical properties. This investigation aims to explore the practical implementation of a digit recognition [...] Read more.
The development of hardware-based cognitive computing systems critically hinges upon the integration of memristor devices capable of versatile weight expression across a spectrum of resistance levels while preserving consistent electrical properties. This investigation aims to explore the practical implementation of a digit recognition system utilizing memristor devices with minimized weighting levels. Through the process of weight quantization for digits represented by 25 or 49 input signals, the study endeavors to ascertain the feasibility of digit recognition via neural network computation. The integration of memristor devices into the system architecture is poised to streamline the representation of the resistors required for weight expression, thereby facilitating the realization of neural-network-based cognitive systems. To minimize the information corruption in the system caused by weight quantization, we introduce the concept of “weight range” in this work. The weight range is the range between the maximum and minimum values of the weights in the neural network. We found that this has a direct impact on weight quantization, which reduces the number of digits represented by a weight below a certain level. This was found to help maintain the information integrity of the entire system despite the reduction in weight levels. Moreover, to validate the efficacy of the proposed methodology, quantized weights are systematically applied to an array of double-layer neural networks. This validation process involves the construction of cross-point array circuits with dimensions of 25 × 10 and 10 × 10, followed by a meticulous examination of the resultant changes in the recognition rate of randomly generated numbers through device simulations. Such endeavors contribute to advancing the understanding and practical implementation of hardware-based cognitive computing systems leveraging memristor devices and weight quantization techniques. Full article
(This article belongs to the Special Issue Thin Film Microelectronic Devices and Circuits)
►▼ Show Figures

Figure 1

18 pages, 5782 KiB  
Article
Quasi-Optical Four-Port Acoustic Filters Based on NEMS Coupled Beam Arrays
by Richard Syms
Micromachines 2024, 15(10), 1257; https://doi.org/10.3390/mi15101257 - 14 Oct 2024
Viewed by 632
Abstract
Theoretical models are presented for quasi-optical four-port acoustic devices based on NEMS-coupled beam arrays. Analogies with coupled mode devices in microwaves, ultrasonics, optics, and electron wave optics are first reviewed, together with coupled beam filters. Power transfer between two mechanically coupled, electrostatically driven, [...] Read more.
Theoretical models are presented for quasi-optical four-port acoustic devices based on NEMS-coupled beam arrays. Analogies with coupled mode devices in microwaves, ultrasonics, optics, and electron wave optics are first reviewed, together with coupled beam filters. Power transfer between two mechanically coupled, electrostatically driven, coupled beam arrays is then demonstrated using a lumped element model, and the conditions for full power transfer are established. Four-port devices, including directional couplers and coupler filters with complementary transmission ports, are then demonstrated. Predictions are verified for realistic device layouts using the stiffness matrix method. Full article
(This article belongs to the Special Issue The 15th Anniversary of Micromachines)
►▼ Show Figures

Figure 1

12 pages, 5227 KiB  
Article
Honeycomb-Shaped Phononic Crystals on 42°Y-X LiTaO3/SiO2/Poly-Si/Si Substrate for Improved Performance and Miniaturization
by Panliang Tang, Hongzhi Pan, Temesgen Bailie Workie, Jia Mi, Jingfu Bao and Ken-ya Hashimoto
Micromachines 2024, 15(10), 1256; https://doi.org/10.3390/mi15101256 - 14 Oct 2024
Viewed by 998
Abstract
A SAW device with a multi-layered piezoelectric substrate has excellent performance due to its high Q value. A multi-layer piezoelectric substrate combined with phononic crystal structures capable of acoustic wave reflection with a very small array can achieve miniaturization and high performance. In [...] Read more.
A SAW device with a multi-layered piezoelectric substrate has excellent performance due to its high Q value. A multi-layer piezoelectric substrate combined with phononic crystal structures capable of acoustic wave reflection with a very small array can achieve miniaturization and high performance. In this paper, a honeycomb-shaped phononic crystal structure based on 42°Y-X LT/SiO2/poly-Si/Si-layered substrate is proposed. The analysis of the bandgap distribution under various filling fractions was carried out using dispersion and transmission characteristics. In order to study the application of PnCs in SAW devices, one-port resonators with different reflectors were compared and analyzed. Based on the frequency response curves and Bode-Q value curves, it was found that when the HC-PnC structure is used as a reflector, it can not only improve the transmission loss of the resonator but also reduce the size of the device. Full article
(This article belongs to the Special Issue Acoustic-Wave-Based Sensors and Microfluidics: Theories, Techniques, and Applications)
►▼ Show Figures

Figure 1

14 pages, 2979 KiB  
Article
Ethanol Production Using Zymomonas mobilis and In Situ Extraction in a Capillary Microreactor
by Julia Surkamp, Lennart Wellmann, Stephan Lütz, Katrin Rosenthal and Norbert Kockmann
Micromachines 2024, 15(10), 1255; https://doi.org/10.3390/mi15101255 - 13 Oct 2024
Viewed by 864
Abstract
The bacterium Zymomonas mobilis is investigated as a model organism for the cultivation and separation of ethanol as a product by in situ extraction in continuous flow microreactors. The considered microreactor is the Coiled Flow Inverter (CFI), which consists of a capillary coiled [...] Read more.
The bacterium Zymomonas mobilis is investigated as a model organism for the cultivation and separation of ethanol as a product by in situ extraction in continuous flow microreactors. The considered microreactor is the Coiled Flow Inverter (CFI), which consists of a capillary coiled onto a support structure. Like other microreactors, the CFI benefits from a high surface-to-volume ratio, which enhances mass and heat transfer. Compared to many other microreactors, the CFI offers the advantage of operating without internal structures, which are often used to ensure good mixing. The simplicity of the design makes the CFI particularly suitable for biochemical applications as cells do not get stuck or damaged by internal structures. Despite this simplicity, good mixing is achieved through flow vortices caused by Taylor and Dean vortices. The reaction system consists of two phases, in which the aqueous phase carries the bacterium and an oleyl alcohol phase is used to extract the ethanol produced. Key parameters for evaluation are bacteria growth and the amount of ethanol produced by the microorganism. The results show the suitability of the CFI for microbial production of valuable compounds. A maximum ethanol concentration of 1.26 g L−1 was achieved for the experiment in the CFI. Overall, the cultivation in the CFI led to faster growth of Z. mobilis, resulting in 25% higher ethanol production than in conducted batch experiments. Full article
►▼ Show Figures

Figure 1

11 pages, 5162 KiB  
Article
Thiol-SAM Concentration Effect on the Performance of Interdigitated Electrode-Based Redox-Free Biosensors
by Abdulaziz K. Assaifan
Micromachines 2024, 15(10), 1254; https://doi.org/10.3390/mi15101254 - 12 Oct 2024
Viewed by 665
Abstract
Despite the direct, redox-free and simple detection non-faradaic impedimetric biosensors offer, considerable optimizations are required to enhance their performance for the detection of various biomarkers. Non-faradaic EIS sensors’ performance depends on the interfacial capacitance between a polarized biosensor surface and the tested sample [...] Read more.
Despite the direct, redox-free and simple detection non-faradaic impedimetric biosensors offer, considerable optimizations are required to enhance their performance for the detection of various biomarkers. Non-faradaic EIS sensors’ performance depends on the interfacial capacitance between a polarized biosensor surface and the tested sample solution. Careful engineering and design of the interfacial capacitance is encouraged to magnify the redout signal upon bioreceptor–antigen interactions. One of the methods to achieve this goal is by optimizing the self-assembled monolayer concentration, which has not been reported for non-faradaic impedimetric sensors. Here, the impact of alkanethiolate (cysteamine) concentration on the performance of gold (Au) interdigitated electrode (Au-IDE) biosensors is reported. Six sets of biosensors were prepared, each with a different cysteamine concentration: 100 nM, 1 μM, 10 μM, 100 μM, 1 mM, and 10 mM. The biosensors were prepared for the direct detection of LDL cholesterol by attaching LDL antibodies on top of the cysteamine via a glutaraldehyde cross-linker. As the concentration of cysteamine increased from 100 nM to 100 μM, the sensitivity of the biosensor increased from 6.7 to 16.2 nF/ln (ng/mL). As the cysteamine concentration increased from 100 μM to 10 mM, the sensitivity deteriorated. The limit of detection (LoD) of the biosensor improved as the cysteamine increased from 100 nM to 100 μM (i.e., 400 ng/mL to 59 pg/mL). However, the LoD started to increase to 67 pg/mL and 16 ng/mL for 1 mM and 10 mM cysteamine concentrations, respectively. This shows that the cysteamine concentration has a detrimental effect on redox-free biosensors. The cysteamine layer has to be as thin as possible and uniformly cover the electrode surfaces to maximize positive readout signals and reduce negative signals, significantly improving both sensitivity and LoD. Full article
(This article belongs to the Special Issue Microelectronics and Optoelectronic Devices: From Fundamental Research to Advanced Applications)
►▼ Show Figures

Figure 1

16 pages, 37042 KiB  
Article
Electrochemical Machining of Micro-Pit Arrays on a GH4169 Alloy with a Roll-Print Mask Using a C6H5Na3O7-Containing NaNO3 Mixed Electrolyte
by Ge Qin, Shiwei Li, Meng Li, Haoyu Peng, Shen Niu, Xinchao Li, Huan Liu, Liang Yan and Pingmei Ming
Micromachines 2024, 15(10), 1253; https://doi.org/10.3390/mi15101253 - 12 Oct 2024
Viewed by 714
Abstract
GH4169 alloy, a nickel-based superalloy known for its excellent high temperature resistance, corrosion resistance, mechanical properties, and high-temperature tribological properties, is widely used in industrial applications, such as in gas turbines for space shuttles and rocket engines. This study addresses the issue of [...] Read more.
GH4169 alloy, a nickel-based superalloy known for its excellent high temperature resistance, corrosion resistance, mechanical properties, and high-temperature tribological properties, is widely used in industrial applications, such as in gas turbines for space shuttles and rocket engines. This study addresses the issue of electrolyte product residue in the electrochemical machining process of a GH4169 alloy by utilizing a C6H5Na3O7-containing NaNO3 new mixed electrolyte. Comparative investigations of the electrochemical behavior and electrolyte product removal mechanisms at different concentrations of C6H5Na3O7 additive in NaNO3 solutions were conducted. The effects of additives, applied voltage, and the rotating speed of the cathode tool on the processing performance of micro-pit arrays on a GH4169 alloy were analyzed. The results indicate that the mixed solution containing C6H5Na3O7 significantly improves the localization and geometric morphology of the micro-pits compared to a single NaNO3 solution. The optimal electrochemical machining parameters were identified as 0.5 wt% C6H5Na3O7 + 10 wt% NaNO3 mixed electrolyte, 12 V applied voltage, and 0.1 r/min rotating speed of the cathode tool. Under these conditions, high-quality micro-pit arrays with an average diameter of 405.85 μm, an average depth of 87.5 μm, and an etch factor (EF) of 1.67 were successfully fabricated, exhibiting excellent morphology, localization, and consistency. Full article
►▼ Show Figures

Figure 1

14 pages, 2817 KiB  
Article
Salivary Cortisol Detection with a Fully Inkjet-Printed Paper-Based Electrochemical Sensor
by Miguel Zea, Hamdi Ben Halima, Rosa Villa, Imad Abrao Nemeir, Nadia Zine, Abdelhamid Errachid and Gemma Gabriel
Micromachines 2024, 15(10), 1252; https://doi.org/10.3390/mi15101252 - 12 Oct 2024
Viewed by 941
Abstract
Electrochemical paper-based analytical devices (ePADs) offer an innovative, low-cost, and environmentally friendly approach for real-time diagnostics. In this study, we developed a functional all-inkjet paper-based electrochemical immunosensor using gold (Au) printed ink to detect salivary cortisol. Covalent binding of the cortisol monoclonal antibody [...] Read more.
Electrochemical paper-based analytical devices (ePADs) offer an innovative, low-cost, and environmentally friendly approach for real-time diagnostics. In this study, we developed a functional all-inkjet paper-based electrochemical immunosensor using gold (Au) printed ink to detect salivary cortisol. Covalent binding of the cortisol monoclonal antibody onto the printed Au surface was achieved through electrodeposition of 4-carboxymethylaniline (CMA), with ethanolamine passivation to prevent non-specific binding. The ePAD exhibited a linear response within the physiological cortisol range (5–20 ng/mL), with sensitivities of 25, 23, and 19 Ω·ng/mL and R2 values of 0.995, 0.979, and 0.99, respectively. Additionally, interference studies against tumor necrosis factor-α (TNF-α) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) yielded excellent results. This novel ePAD, fabricated using inkjet printing technology on paper, simplifies the process, reduces environmental impact, and lowers fabrication costs. Full article
(This article belongs to the Special Issue Microelectrodes and Microdevices for Electrochemical Applications)
►▼ Show Figures

Figure 1

13 pages, 2724 KiB  
Article
Reverse Design of Pixel-Type Micro-Polarizer Arrays to Improve Polarization Image Contrast
by Yonggui Shi, Zhihai Lin, Tianran Wang, Chaokai Huang, Hui Chen, Jianxiong Chen and Yu Xie
Micromachines 2024, 15(10), 1251; https://doi.org/10.3390/mi15101251 - 12 Oct 2024
Viewed by 651
Abstract
Micro-polarizer array (MPA) is the core optical component of the Division of Focal-Plane (DoFP) imaging system, and its design is very important to the system’s performance. Traditional design methods rely on theoretical analysis and simulation, which is complicated and requires designers to have [...] Read more.
Micro-polarizer array (MPA) is the core optical component of the Division of Focal-Plane (DoFP) imaging system, and its design is very important to the system’s performance. Traditional design methods rely on theoretical analysis and simulation, which is complicated and requires designers to have profound theoretical foundations. In order to simplify the design process and improve efficiency, this paper proposes a 2 × 2 MPA reverse-design strategy based on particle swarm optimization (PSO). This strategy uses intelligent algorithms to automatically explore the design space in order to discover MPA structures with optimal optical properties. In addition, the all-pass filter is introduced to the MPA superpixel unit in the design, which effectively reduces the crosstalk and frequency aliasing between pixels. In this study, two MPA models were designed: a traditional MPA and an MPA with an all-pass filter. The Degree of Linear Polarization (DOLP) image contrast is used as the evaluation standard and compared with the traditional MPA; the results show that the contrast of the newly designed traditional MPA image is increased by 21%, and the MPA image with the all-pass filter is significantly increased by 82%. Therefore, the reverse-design method proposed in this paper not only simplifies the design process but also can design an MPA with enhanced optical performance, which has obvious advantages over the traditional method. Full article
(This article belongs to the Special Issue Advanced Optical Manufacturing Technologies and Applications)
►▼ Show Figures

Figure 1

19 pages, 10733 KiB  
Article
Image-Based Auto-Focus Microscope System with Visual Servo Control for Micro-Stereolithography
by Yijie Liu, Xuexuan Li, Pengfei Jiang, Ziyue Wang, Jichang Guo, Chao Luo, Yaozhong Wei, Zhiliang Chen, Chang Liu, Wang Ren, Wei Zhang, Juntian Qu and Zhen Zhang
Micromachines 2024, 15(10), 1250; https://doi.org/10.3390/mi15101250 - 11 Oct 2024
Viewed by 789
Abstract
Micro-stereolithography (μSL) is an advanced additive manufacturing technique that enables the fabrication of highly precise microstructures with fine feature resolution. One of the primary challenges in μSL is achieving and maintaining precise focus throughout the fabrication process. For the successful [...] Read more.
Micro-stereolithography (μSL) is an advanced additive manufacturing technique that enables the fabrication of highly precise microstructures with fine feature resolution. One of the primary challenges in μSL is achieving and maintaining precise focus throughout the fabrication process. For the successful application of μSL, it is essential to maintain the sample surface within a focal depth of several microns. Despite the growing interest in auto-focus devices, limited attention has been directed towards auto-focus systems in image-based auto-focus microscope systems for precision μSL. To address this challenge, we propose an image-based auto-focus microscope system incorporating visual servo control. In the optical design, a transflective beam splitter is employed, allowing the laser beam to pass through for fabrication while reflecting the focused beam on the sample surface to the microscope and camera. Utilizing captured spot images and the Foucault knife-edge test, a deep learning-based laser spot image processing algorithm is developed to determine the focus position based on spot size and the number of spot pixels on both sides. Experimental results demonstrate that the proposed auto-focus system effectively determines the relative position of the focal point using the laser spot image and achieves auto-focusing through visual servo control. Full article
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-103
Previous Issue
Next Issue
Back to TopTop