Micromachines

14 pages, 2054 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Paperclip-Type Flexible Inductive Sensor Based on Liquid Metal Coils for Simple Fabrication and Multifunctional Applications

by Xun Sun, Kaixin Li, Zifeng Zhang, Linling Xiang, Yihao Zhou and Bin Sheng

Micromachines 2025, 16(8), 965; https://doi.org/10.3390/mi16080965 - 21 Aug 2025

Viewed by 451

Abstract

At present, high-resolution and reliable inductive sensors have increasingly emerged as a pivotal component in the advancement of flexible electronic devices. The integration of liquid metal with flexible substrates presents a promising approach for the fabrication of inductive sensors. This paper introduces a [...] Read more.

At present, high-resolution and reliable inductive sensors have increasingly emerged as a pivotal component in the advancement of flexible electronic devices. The integration of liquid metal with flexible substrates presents a promising approach for the fabrication of inductive sensors. This paper introduces a novel paperclip-type helical coil inductive sensor, characterized by advancements in both structural design and a simplified manufacturing process. The sensor comprises a fine silicone tube filled with liquid metal, encapsulated within polydimethylsiloxane (PDMS) glue. A significant innovation of this design is its complete elimination of the need for high-precision sacrificial metal molds. This approach bypasses complex processes such as precision mold machining, demolding, and post-mold residue cleaning, thereby significantly streamlining the production work-flow. We optimized the parameters of the paperclip-type helical coil, the aspect ratio, and the number of turns, achieving the maximum sensitivity under limited conditions. Experimental results demonstrate that this sensor is capable of tensile, pressure, and non-contact distance sensing. The linearity of the tensile sensing is exceptional (

R^{2} = 0.999

), with consistent performance observed after 800 tensile cycles. The pressure sensing range extends from 0 to 230 kPa, and the non-contact distance sensing is effective within a range of 10 mm. Furthermore, the sensor exhibits strong performance in monitoring human physiological activities and metal distance detection, demonstrating significant application potential in flexible electronics and wearable devices. Full article

(This article belongs to the Special Issue Structural Analyses and Designs for Flexible/Stretchable Electronics, 3rd Edition)

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29 pages, 9158 KB

Open AccessReview

Advancements and Future Prospects of Energy Harvesting Technology in Power Systems

by Haojie Du, Jiajing Lu, Wenye Zhang, Guang Yang, Wenzhuo Zhang, Zejun Xu, Huifeng Wang, Kejie Dai and Lingxiao Gao

Micromachines 2025, 16(8), 964; https://doi.org/10.3390/mi16080964 - 21 Aug 2025

Viewed by 664

Abstract

The electric power equipment industry is rapidly advancing toward “informationization,” with the swift progression of intelligent sensing technology serving as a key driving force behind this transformation, thereby triggering significant changes in global electric power equipment. In this process, intelligent sensing has created [...] Read more.

The electric power equipment industry is rapidly advancing toward “informationization,” with the swift progression of intelligent sensing technology serving as a key driving force behind this transformation, thereby triggering significant changes in global electric power equipment. In this process, intelligent sensing has created an urgent demand for high-performance integrated power systems that feature compact size, lightweight design, long operational life, high reliability, high energy density, and low cost. However, the performance metrics of traditional power supplies have increasingly failed to meet the requirements of modern intelligent sensing, thereby significantly hindering the advancement of intelligent power equipment. Energy harvesting technology, characterized by its long operational lifespan, compact size, environmental sustainability, and self-sufficient operation, is capable of capturing renewable energy from ambient power sources and converting it into electrical energy to supply power to sensors. Due to these advantages, it has garnered significant attention in the field of power sensing. This paper presents a comprehensive review of the current state of development of energy harvesting technologies within the power environment. It outlines recent advancements in magnetic field energy harvesting, electric field energy harvesting, vibration energy harvesting, wind energy harvesting, and solar energy harvesting. Furthermore, it explores the integration of multiple physical mechanisms and hybrid energy sources aimed at enhancing self-powered applications in this domain. A comparative analysis of the advantages and limitations associated with each technology is also provided. Additionally, the paper discusses potential future directions for the development of energy harvesting technologies in the power environment. Full article

(This article belongs to the Special Issue Nanogenerators: Design, Fabrication and Applications)

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21 pages, 4566 KB

Open AccessArticle

A Suppression Method for Random Errors of IFOG Based on the Decoupling of Colored Noise-Spectrum Information

by Zhe Liang, Zhili Zhang, Zhaofa Zhou, Hongcai Li, Junyang Zhao, Longjie Tian and Hui Duan

Micromachines 2025, 16(8), 963; https://doi.org/10.3390/mi16080963 - 21 Aug 2025

Viewed by 300

Abstract

In high-precision inertial navigation systems, suppressing the random errors of a fiber-optic gyroscope is of great importance. However, the traditional rule-based autoregressive moving average modeling method, when applied in Kalman filtering considering colored noise, presents inherent disadvantages in principle, including inaccurate state equations [...] Read more.

In high-precision inertial navigation systems, suppressing the random errors of a fiber-optic gyroscope is of great importance. However, the traditional rule-based autoregressive moving average modeling method, when applied in Kalman filtering considering colored noise, presents inherent disadvantages in principle, including inaccurate state equations and difficulties in state dimension expansion. To this end, the noise characteristics in the fiber-optic gyroscope signal are first deeply analyzed, a random error model form is clarified, and a new model-order determination criterion is proposed to achieve the high-precision modeling of random errors. Then, based on the effective suppression of the angle random walk error of the fiber-optic gyroscope, and combined with the linear system equation of its colored noise, an adaptive Kalman filter based on noise-spectrum information decoupling is designed. This breaks through the principled limitations of traditional methods in suppressing colored noise and provides a scheme for modeling and suppressing fiber-optic gyroscope random errors under static conditions. Experimental results show that, compared with existing methods, the initial alignment accuracy of the proposed method based on 5 min data of fiber-strapdown inertial navigation is improved by an average of 48%. Full article

(This article belongs to the Special Issue Integrated Photonics and Optoelectronics, 2nd Edition)

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14 pages, 2771 KB

Open AccessArticle

Investigation into Ultrasonic Oscillation-Assisted Nickel Electroplating onto a Diamond Surface

by Qingming Fan, Bin Guo, Guokang Su, Hui Qi, Pengfan Li, Chuanyun Zhang and Kai Cheng

Micromachines 2025, 16(8), 962; https://doi.org/10.3390/mi16080962 - 21 Aug 2025

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Abstract

At present, there are some challenging issues for diamond electroplating devices, such as poor particle–cathode contact uniformity, low conductivity, inefficient deposition, and complex disassembly/cleaning process of the device. To overcome these issues, an ultrasonic oscillation-assisted nickel electroplating device is innovatively designed and presented [...] Read more.

At present, there are some challenging issues for diamond electroplating devices, such as poor particle–cathode contact uniformity, low conductivity, inefficient deposition, and complex disassembly/cleaning process of the device. To overcome these issues, an ultrasonic oscillation-assisted nickel electroplating device is innovatively designed and presented in this paper. The device features: (1) innovative architecture enabling rapid disassembly; (2) ultrasonic enhancement of diamond particle mobility (frequency × amplitude); (3) optimized electrical contact interfaces. In this paper, the effects of electroplating current, output power of ultrasonic oscillator and diamond particle size on nickel electroplating onto diamond surface are further studied particularly by ultrasonic assisted electroplating. The experimental results show that the ultrasonic oscillation assisted electroplating greatly improves the uniformity of the coating on the diamond surface and effectively prevents the adhesion between diamond particles. While the process parameters are electroplating current of 3 A, output power of ultrasonic oscillator 900 W, diamond particle size of 120/140, the weight-gain rate is 20.6%, the nickel content of the coating reaches 81.95%, and the coating is excellent uniformed without agglomeration. The research presented provides fundamental understanding for further development and application of ultrasonic oscillation-assisted electroplating technology particularly for broad precision engineering purposes. Full article

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13 pages, 4654 KB

Open AccessArticle

Design and Parameter Optimization of Quasi-Zero-Stiffness Structures Based on Cosine-Curve Compliant Beams

by Zhuo Sun, Jinpeng Hu, Deng Li and Long Huang

Micromachines 2025, 16(8), 961; https://doi.org/10.3390/mi16080961 - 21 Aug 2025

Viewed by 432

Abstract

Quasi-zero-stiffness (QZS) structures can provide a near constant force output in a certain range of displacement without force sensors and controllers. Therefore, they can be used in overload protection, vibration isolation, and biomedical application. In this paper, we propose a novel QZS structure [...] Read more.

Quasi-zero-stiffness (QZS) structures can provide a near constant force output in a certain range of displacement without force sensors and controllers. Therefore, they can be used in overload protection, vibration isolation, and biomedical application. In this paper, we propose a novel QZS structure based on cosine-curve compliant beams, which have a large QZS stoke and compact layout. The proposed QZS structure is composed of two half-period cosine-curve compliant beams with negative stiffness and two one-period cosine-curve compliant beams with positive stiffness. Then, we conducted the modeling of the force-displacement relationship of the compliant beams and analyzed the influence of the parameters on the mechanical performance. Based on the influence analysis, we propose the optimization processes to achieve QZS and obtain a QZS structure with the required force-displacement behavior. Finally, the mechanical performance of the QZS structure is verified through compression experiments on the prototype. Full article

(This article belongs to the Section E：Engineering and Technology)

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18 pages, 1808 KB

Open AccessArticle

Holmium Metal Nanoparticle PbO₂ Anode Formed by Electrodeposition for Efficient Removal of Insecticide Acetamiprid and Improved Oxygen Evolution Reaction

by Milica Kaludjerović, Sladjana Savić, Danica Bajuk-Bogdanović, Aleksandar Jovanović, Lazar Rakočević, Goran Roglić, Jadranka Milikić and Dalibor Stanković

Micromachines 2025, 16(8), 960; https://doi.org/10.3390/mi16080960 - 20 Aug 2025

Viewed by 462

Abstract

This work examines the possibility of using a PbO₂-based electrode doped with the rare-earth metal holmium in the field of oxygen evolution and the development of an efficient method for the degradation of acetamiprid. Acetamiprid is a widely used insecticide and, [...] Read more.

This work examines the possibility of using a PbO₂-based electrode doped with the rare-earth metal holmium in the field of oxygen evolution and the development of an efficient method for the degradation of acetamiprid. Acetamiprid is a widely used insecticide and, as such, it very often reaches waterways, where it can cause many problems for wildlife and the environment. X-ray powder diffraction analysis, Raman spectroscopy, and energy-dispersive X-ray spectroscopy results confirmed the structure of Ti/SnO₂-Sb₂O₃/Ho-PbO₂, while the morphology of its surface was investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy. Ti/SnO₂-Sb₂O₃/Ho-PbO₂ showed good OER activity in alkaline media with a Tafel slope of 138 mV dec⁻¹. The Ti/SnO₂-Sb₂O₃/Ho-PbO₂ electrode shows very good efficiency in removing acetamiprid. By optimizing the degradation procedure, the following operating conditions were obtained: a current density of 20 mA cm⁻², a pH value of the supporting electrolyte (sodium sulfate) of 2, and a concentration of the supporting electrolyte of 0.035 M. After optimization, the maximum efficiency of removing acetamiprid (10 mg L⁻¹, 4.5 × 10⁻⁵ mol) from water was achieved, 96.8%, after only 90 min of treatment, which represents an efficiency of 1.125 mol cm⁻² of the electrode. Additionally, it was shown that the degradation efficiency is strictly related to the concentration of the treated substance. Full article

(This article belongs to the Special Issue Nanoparticle-Based (Bio)Sensors for Biomedical and Environmental Monitoring)

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23 pages, 5532 KB

Open AccessArticle

Pulsed CO₂ Laser-Fabricated Cascades of Double Resonance Long Period Gratings for Sensing Applications

by Tinko Eftimov, Sanaz Shoar Ghaffari, Georgi Dyankov, Veselin Vladev and Alla Arapova

Micromachines 2025, 16(8), 959; https://doi.org/10.3390/mi16080959 - 20 Aug 2025

Viewed by 311

Abstract

We present a detailed theoretical and experimental study of cascaded double resonance long period gratings (C DR LPGs) for fabricated sensing applications. The matrix description of cascaded LPGs is presented, and several important particular cases are considered related to the regular and turn [...] Read more.

We present a detailed theoretical and experimental study of cascaded double resonance long period gratings (C DR LPGs) for fabricated sensing applications. The matrix description of cascaded LPGs is presented, and several important particular cases are considered related to the regular and turn around point (TAP) gratings. A pulsed CO₂ laser was used to fabricate ordinary and cascaded DR LPGs in a photosensitive optical fiber. The responses of the fabricated C DR LPGs to surrounding refractive index (SRI) temperature as well to longitudinal strain have been studied. A statistical comparison of the SRI sensitivities of ordinary and cascaded DR LPGs is presented to outline the capabilities and advantages of cascaded DR gratings. It was experimentally established that the temperature dependence of the wavelength split at the TAP follows a logarithmic dependence and the sensitivity to temperature is inversely proportional to the temperature itself. We evaluate the temperature stability needed for SRI-based sensing application and the importance of fine-tuning to the operational point slightly after the TAP to ensure maximum sensitivity of the sensor. Full article

(This article belongs to the Special Issue Micro- and Nanosensors: Fabrication, Applications and Performance Enhancements, Third Edition)

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9 pages, 882 KB

Open AccessArticle

Sensitivity and Contrast Characterization of PMMA 950K Resist Under 30 keV Focused Ga⁺ Ion Beam Exposure

by Mukhit Muratov, Yana Shabelnikova, Sergey Zaitsev, Renata Nemkayeva and Nazim Guseinov

Micromachines 2025, 16(8), 958; https://doi.org/10.3390/mi16080958 - 20 Aug 2025

Viewed by 419

Abstract

In this study, the key lithographic performance of PMMA 950K resist was evaluated by exposure to a 30 keV focused gallium (Ga⁺) ion beam. The sensitivity and contrast of PMMA 950K were directly compared with those of electron exposure under identical [...] Read more.

In this study, the key lithographic performance of PMMA 950K resist was evaluated by exposure to a 30 keV focused gallium (Ga⁺) ion beam. The sensitivity and contrast of PMMA 950K were directly compared with those of electron exposure under identical development conditions. It was found that the sensitivity of PMMA 950K to Ga⁺ ions for 50 nm films reaches a value of about 0.4 μC/cm², which is more than 250 times higher than its sensitivity to electron exposure. A method for evaluating the resist contrast during ion exposure is proposed in this work, taking into account the highly non-uniform dose distribution across the resist depth; it yielded a contrast value of γ = 2.6, which is consistent with the result obtained with electron exposure (γ = 2.8). In addition, a pronounced dependence of the resist sensitivity on the resist thickness was found: with an increase in thickness from 10 nm to 60 nm the sensitivity decreases by an order of magnitude. The obtained results form a reliable methodological basis for characterizing the behavior of polymer resists under ion irradiation and provide valuable recommendations for optimizing lithography with a focused beam of Ga⁺ ions when creating nanostructures for microelectronics, photonics, and quantum technologies. Full article

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18 pages, 3836 KB

Open AccessArticle

A Microfluidic Approach for Assessing the Rheological Properties of Healthy Versus Thalassemic Red Blood Cells

by Hao Jiang, Xueying Li, Zhuoyan Liu, Siyu Luo, Junbin Huang, Chun Chen, Rui Chen and Fenfang Li

Micromachines 2025, 16(8), 957; https://doi.org/10.3390/mi16080957 - 19 Aug 2025

Viewed by 498

Abstract

The deformability of red blood cells (RBCs) is critical for microvascular circulation and is impaired in hematological disorders such as thalassemia, a prevalent public health concern in Guangdong, China. While microfluidics enable high-precision deformability assessment, current studies lack standardization in deformation metrics and [...] Read more.

The deformability of red blood cells (RBCs) is critical for microvascular circulation and is impaired in hematological disorders such as thalassemia, a prevalent public health concern in Guangdong, China. While microfluidics enable high-precision deformability assessment, current studies lack standardization in deformation metrics and rarely investigate post-deformation recovery dynamics. This study introduces an automated microfluidic platform for systematically evaluating RBC deformability in healthy and thalassemic individuals. A biomimetic chip featuring 4 µm, 8 µm, and 16 µm wide channels (7 µm in height) was designed to simulate capillary dimensions, with COMSOL CFD numerical modeling validating shear stress profiles. RBC suspensions (10⁷ cells/mL in DPBS) were hydrodynamically focused through constrictions while high-speed imaging (15,000 fps) captured deformation–recovery dynamics. Custom-built algorithms with deep-learning networks automated cell tracking, contour analysis, and multi-parametric quantification. Validation confirmed significantly reduced deformability in Paraformaldehyde (PFA)-treated RBCs compared to normal controls. Narrower channels and higher flow velocities amplified shear-induced deformations, with more deformable cells exhibiting faster post-constriction shape recovery. Crucially, the platform distinguished thalassemia patient-derived RBCs from healthy samples, revealing significantly lower deformability in diseased cells, particularly in 4 µm channels. These results establish a standardized, high-throughput framework for RBC mechanical characterization, uncovering previously unreported recovery dynamics and clinically relevant differences in deformability in thalassemia. The method’s diagnostic sensitivity highlights its translational potential for screening hematological disorders. Full article

(This article belongs to the Special Issue Application of Microfluidic Technology in Bioengineering)

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18 pages, 6030 KB

Open AccessArticle

Impact of Rapid Thermal Annealing and Oxygen Concentration on Symmetry Bipolar Switching Characteristics of Tin Oxide-Based Memory Devices

by Kai-Huang Chen, Chien-Min Cheng, Ming-Cheng Kao, Hsin-Chin Chen, Yao-Chin Wang and Yu-Han Tsai

Micromachines 2025, 16(8), 956; https://doi.org/10.3390/mi16080956 - 19 Aug 2025

Viewed by 393

Abstract

In this study, tin oxide (SnO₂) resistive random-access memory (RRAM) thin films were fabricated using the thermal evaporation and radiofrequency and dc frequency sputtering techniques for metal–insulator–metal (MIM) structures. The fabrication process began with the deposition of a silicon dioxide (SiO [...] Read more.

In this study, tin oxide (SnO₂) resistive random-access memory (RRAM) thin films were fabricated using the thermal evaporation and radiofrequency and dc frequency sputtering techniques for metal–insulator–metal (MIM) structures. The fabrication process began with the deposition of a silicon dioxide (SiO₂) layer onto a silicon (Si) substrate, followed by the deposition of a titanium nitride (TiN) layer to serve as the bottom electrode. Subsequently, the tin oxide (SnO₂) layer was deposited as the resistive switching insulator. Two types of top electrodes were developed to investigate the influence of different oxygen concentrations on the bipolar switching, electrical characteristics, and performance of memory devices. An aluminum (Al) top electrode was deposited using thermal evaporation, while a platinum (Pt) top electrode was deposited via dc sputtering. As a result, two distinct metal–insulator–metal (MIM) memory RRAM device structures were formed, i.e., Al/SnO₂/TiN/SiO₂/Si and Pt/SnO₂/TiN/SiO₂/Si. In addition, the symmetry bipolar switching characteristics, electrical conduction mechanism, and oxygen concentration factor of the tin oxide-based memory devices using rapid thermal annealing and different top electrodes were determined and investigated by ohmic, space-charge-limit-current, Schottky, and Poole–Frenkel conduction equations in this study. Full article

(This article belongs to the Special Issue Resistive Random Access Memory Devices: Mechanisms, Materials, Devices, and Applications)

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14 pages, 1966 KB

Open AccessArticle

Pre-Silicon Accurate SPICE Modeling of Trench MOSFETs via Advanced TCAD Simulations and Dynamic Validation

by Ammar Tariq, Giovanni Minardi, Valeria Cinnera Martino, Enza Fazio, Salvatore Rinaudo, Giuseppe Privitera, Fortunato Neri and Carmelo Corsaro

Micromachines 2025, 16(8), 955; https://doi.org/10.3390/mi16080955 - 19 Aug 2025

Viewed by 391

Abstract

This work presents a novel and fully virtual flow for extracting the SPICE model of a power MOSFET, starting exclusively from TCAD simulations. Unlike traditional approaches that rely on experimental silicon data, our methodology enables designers to optimize the device performance and extract [...] Read more.

This work presents a novel and fully virtual flow for extracting the SPICE model of a power MOSFET, starting exclusively from TCAD simulations. Unlike traditional approaches that rely on experimental silicon data, our methodology enables designers to optimize the device performance and extract accurate electrical parameters before any physical prototyping is required. By leveraging advanced TCAD tools, we generate a realistic device structure and obtain all the key electrical characteristics, which are then used for precise SPICE model extraction and macromodel integration. The extracted model is dynamically validated using a gate-charge test performed identically in both the TCAD and SPICE environments, demonstrating excellent agreement with less than a 2% error in the charge quantities, Q_gs and Q_gd. This approach proves that initial silicon prototyping can be confidently bypassed, and it is highly innovative because it enables designers to achieve highly faithful device simulations before hardware fabrication. This significantly reduces the need for costly and time-consuming prototyping and design re-spins, accelerating the development process while enhancing the accuracy in terms of the transient and dynamic characteristics of MOSFETs designed for specific applications; in our case, for an e-fuse to be integrated into a more complex system. Full article

(This article belongs to the Special Issue Power Semiconductor Devices and Applications, 3rd Edition)

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12 pages, 2391 KB

Open AccessArticle

Structural and Electrically Conductive Properties of Plasma-Enhanced Chemical-Vapor-Deposited High-Resistivity Zn-Doped β-Ga₂O₃ Thin Films

by Leonid A. Mochalov, Sergey V. Telegin, Aleksei V. Almaev, Ekaterina A. Slapovskaya and Pavel A. Yunin

Micromachines 2025, 16(8), 954; https://doi.org/10.3390/mi16080954 - 19 Aug 2025

Viewed by 614

Abstract

A method was developed for plasma-enhanced chemical vapor deposition of β-Ga₂O₃:Zn thin films with the possibility of pre-purifying precursors. The structural and electrically conductive properties of β-Ga₂O₃:Zn thin films were studied. Increasing the temperature of [...] Read more.

A method was developed for plasma-enhanced chemical vapor deposition of β-Ga₂O₃:Zn thin films with the possibility of pre-purifying precursors. The structural and electrically conductive properties of β-Ga₂O₃:Zn thin films were studied. Increasing the temperature of the Zn source (T_Zn) to 220 °C led to the formation of Ga₂O₃ films with a Zn concentration of 4 at.%, at T_Zn = 230 °C [Zn] = 6 at.% and at 235 °C. [Zn] = 8 at.% At T_Zn = 23 °C, the films corresponded to the β-Ga₂O₃ phase and were single-crystalline with a surface orientation of (–201). As T_Zn increased, the polycrystalline structure of β-Ga₂O₃ films with a predominant orientation of (111) was formed. The introduction of Zn led to the formation of a more developed microrelief of the surface. Raman spectroscopy showed that a small concentration of impurity atoms tended to replace gallium atoms in the oxide lattice, which was also confirmed by the Hall measurements. The concentration of charge carriers upon the introduction of Zn, which is a deep acceptor, decreased by 2–3 orders of magnitude, which mainly determined the decrease in the films’ resistivity. The resulting thin films were promising for the development of high-resistivity areas of β-Ga₂O₃-based devices. Full article

(This article belongs to the Special Issue Thin Film Microelectronic Devices and Circuits, 2nd Edition)

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15 pages, 4134 KB

Open AccessArticle

A Novel Open-Loop Current Sensor Based on Multiple Spin Valve Sensors and Magnetic Shunt Effect with Position Deviation Calibration

by Tianbin Xu, Tian Lan, Jiaye Yu, Yu Fu, Boyan Li, Tengda Yang and Ru Bai

Micromachines 2025, 16(8), 953; https://doi.org/10.3390/mi16080953 - 19 Aug 2025

Viewed by 353

Abstract

To address the demands for wide-range and high-precision current measurement, this paper proposes a novel current sensor design that integrates spin sensing technology, magnetic shunt effect, and a multi-sensor data fusion algorithm. The spin valve sensors accurately detect the magnetic field generated by [...] Read more.

To address the demands for wide-range and high-precision current measurement, this paper proposes a novel current sensor design that integrates spin sensing technology, magnetic shunt effect, and a multi-sensor data fusion algorithm. The spin valve sensors accurately detect the magnetic field generated by the signal current, while the soft magnetic shunt structure attenuates the magnetic field to a level suitable for the spin valve sensors. Consequently, the detection current range can be extended by 6.8 times. Using four spin valve sensors and data fusion with an averaging algorithm, the system can calibrate the errors caused by the displacement or tilt of the current-carrying wire. Experimental results demonstrate that the current sensor achieves a sensitivity of 61.6 mV/V/A, an excellent linearity of 0.55%, and robust measurement performance, as well as strong anti-interference capability. Our study offers a novel solution for high-precision, wide-range current measurement in applications such as those in new energy vehicle electronics and precision electric energy metering. Full article

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12 pages, 3318 KB

Open AccessArticle

Influence of the Inducer on the Performance of a Miniature High-Speed Centrifugal Pump

by Yifu Hou, Xiaonian Zeng and Yuchuan Wang

Micromachines 2025, 16(8), 952; https://doi.org/10.3390/mi16080952 - 19 Aug 2025

Viewed by 442

Abstract

The inclusion of an inducer is an effective approach to improve the cavitation performance of centrifugal pumps, significantly influencing both the internal flow characteristics and the external performance of the pumps. This study examines a miniature high-speed centrifugal pump (MHCP) using numerical simulations [...] Read more.

The inclusion of an inducer is an effective approach to improve the cavitation performance of centrifugal pumps, significantly influencing both the internal flow characteristics and the external performance of the pumps. This study examines a miniature high-speed centrifugal pump (MHCP) using numerical simulations based on the k-ε turbulence model, comparing the cases with an inducer and without one. Experimental tests on the pump’s external performance are conducted and flow visualization images are presented to validate the findings. The effects of the inducer on the tip leakage backflow, cavitation performance, and external pump performance are analyzed. The results show that the inducer provides pre-pressurization of the fluid, leading to a higher circumferential velocity at the impeller inlet and a reduced inlet flow angle. This allows for a reduction in the impeller blade inlet angle, resulting in smoother flow streamlines inside the impeller. Moreover, the inducer helps to suppress local low-pressure regions caused by the vortex and cavities generated by the interaction between the tip clearance backflow and the main flow, thereby mitigating cavitation in the non-blade zone. Within the investigated operating range, the pump with an inducer exhibits a significantly improved external hydraulic performance, including an increased head and efficiency, a reduced required net positive suction head (NPSHr), and a broader stable operating range. Full article

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11 pages, 1576 KB

Open AccessArticle

Proof-of-Concept Development of a Bioelectric Biosensor Using Arduino for Monitoring Dopaminergic Response in Neuroblastoma Cells

by Magdalene Pappa and Spyridon Kintzios

Micromachines 2025, 16(8), 951; https://doi.org/10.3390/mi16080951 - 19 Aug 2025

Viewed by 665

Abstract

This study presents the proof-of-concept design and preliminary implementation of a bioelectric biosensor based on an Arduino platform for real-time monitoring of gel-immobilized N2a neuroblastoma cells using dopamine as a model neurotransmitter. The sensor operates on the principle of bioelectric recognition assay (BERA), [...] Read more.

This study presents the proof-of-concept design and preliminary implementation of a bioelectric biosensor based on an Arduino platform for real-time monitoring of gel-immobilized N2a neuroblastoma cells using dopamine as a model neurotransmitter. The sensor operates on the principle of bioelectric recognition assay (BERA), and uses a two-electrode set-up as a simple, cost-efficient way to capture electrophysiological responses following dopamine exposure, while at the same time mimicking the in vivo cellular environment. Cellular ohmic resistance was assessed under increasing dopamine concentrations and temperatures (24 °C and 37 °C). The results showed that temperature significantly affected cell responses to increasing dopamine concentrations, possibly because of differences in dopamine diffusion in gel, which may in turn have affected membrane polarization and overall cell electric resistance. Pending further testing against a wider range of dopamine concentrations along with various dopamine agonists/antagonists, as well as optimization in terms of specificity, selectivity, and sensitivity, the biosensor could be applied in bioscreening and neuropharmacological studies in a user-friendly, scalable way. Full article

(This article belongs to the Special Issue Bioelectronics and Its Limitless Possibilities)

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15 pages, 856 KB

Open AccessArticle

Research on a General SER Rate Prediction Model Based on a Set of Configuration Parameters Related to SER

by Shougang Du, Shulong Wang and Shupeng Chen

Micromachines 2025, 16(8), 950; https://doi.org/10.3390/mi16080950 - 19 Aug 2025

Viewed by 387

Abstract

This article comprehensively analyzes the new developments and challenges faced by several typical prediction models in the field of radiation effects in recent years. The models discussed include the RPP model, the extended RPP (rectangular parallelepiped) model, and the IRPP (integral rectangular parallelepiped) [...] Read more.

This article comprehensively analyzes the new developments and challenges faced by several typical prediction models in the field of radiation effects in recent years. The models discussed include the RPP model, the extended RPP (rectangular parallelepiped) model, and the IRPP (integral rectangular parallelepiped) model. The article conducts a comprehensive analysis of the limitations of the assumption that uses the linear energy transfer (LET) of incident particles and the SEU (single-particle upset) cross-section (without considering the energy and type of ions) to predict the rate of single-particle effects (SEUs). Additionally, the article points out that with the continuous progress of integrated circuit technology, the geometric shape of the target circuit, the energy of the incident particles, the type of particles, and more precise physical models corresponding to the interaction between radiation and matter have become increasingly important in evaluating the sensitivity to single-particle effects (SEEs). Subsequently, based on the probability characteristics of SEE, a series of general estimation equations for the SEE rate are derived, considering particle energy, particle type, and the probability of influence at a specific moment. Then, by introducing the concept of interaction volume, the concept of sensitive volume is further expanded, and using these general equations, the relationship between the SEE rate cross-section and the SEE projected area is derived, simplifying the SEU rate prediction equation to a form that can be directly used in engineering applications. Finally, the article emphasizes a complete method of applying the general prediction equation to engineering to estimate the radiation disturbance performance of two typical verification circuits, and provides the corresponding prediction results. Full article

(This article belongs to the Special Issue High-Reliability Semiconductor Devices and Integrated Circuits, 3rd Edition)

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14 pages, 6767 KB

Open AccessArticle

Reduction of Visual Artifacts in Laser Beam Scanning Displays

by Peng Zhou, Huijun Yu, Xiaoguang Li, Wenjiang Shen and Dongmin Wu

Micromachines 2025, 16(8), 949; https://doi.org/10.3390/mi16080949 - 19 Aug 2025

Viewed by 391

Abstract

Laser beam scanning (LBS) projection systems based on MEMS micromirrors offer advantages such as compact size, low power consumption, and vivid color performance, making them well suited for applications like AR glasses and portable projectors. Among various scanning methods, raster scanning is widely [...] Read more.

Laser beam scanning (LBS) projection systems based on MEMS micromirrors offer advantages such as compact size, low power consumption, and vivid color performance, making them well suited for applications like AR glasses and portable projectors. Among various scanning methods, raster scanning is widely adopted; however, it suffers from artifacts such as dark bands between adjacent scanning lines and non-uniform distribution of the scanning trajectory relative to the original image. These issues degrade the overall viewing experience. In this study, we address these problems by introducing random variations to the slow-axis driving signal to alter the vertical offset of the scanning trajectories between different scan cycles. The variation is defined as an integer multiple of 1/8 of the fast-axis scanning period (

1 / f_{h}

) Due to the temporal integration effect of human vision, trajectories from different cycles overlap, thereby enhancing the scanning fill factor relative to the target image area. The simulation and experimental results demonstrate that the maximum ratio of non-uniform line spacing is reduced from 7:1 to 1:1, and the modulation of the scanned display image is reduced to 0.0006—below the human eye’s contrast threshold of 0.0039 under the given experimental conditions. This method effectively addresses scanning display artifacts without requiring additional hardware modifications. Full article

(This article belongs to the Special Issue Recent Advances in MEMS Mirrors)

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16 pages, 5152 KB

Open AccessArticle

Simulation-Based Design of an Electrically Tunable Beam-Steering Metasurface Driven by a Triboelectric Nanogenerator

by Penghui Luo, Longlong Zhang, Shuaixing Wang and Zhiyuan Zhu

Micromachines 2025, 16(8), 948; https://doi.org/10.3390/mi16080948 - 19 Aug 2025

Viewed by 411

Abstract

This study presents a simulation-based feasibility analysis of a beam steering metasurface, theoretically driven by mechanical energy harvested from human motion via a triboelectric nanogenerator (TENG). In the proposed model, the TENG converts biomechanical motion into alternating current (AC), which is rectified into [...] Read more.

This study presents a simulation-based feasibility analysis of a beam steering metasurface, theoretically driven by mechanical energy harvested from human motion via a triboelectric nanogenerator (TENG). In the proposed model, the TENG converts biomechanical motion into alternating current (AC), which is rectified into direct current (DC) to bias varactor diodes integrated into each metasurface unit cell. These bias voltages are numerically applied to dynamically modulate the local reflection phase, enabling beam steering without external power. Full-wave electromagnetic simulations were conducted to confirm the feasibility of beam manipulation under TENG-generated voltage levels. The proposed simulation-driven design offers a promising framework for battery-free, adaptive electromagnetic control with potential applications in wearable electronics, intelligent sensing, and energy-autonomous radar systems. Full article

(This article belongs to the Special Issue Micro-Energy Harvesting Technologies and Self-Powered Sensing Systems)

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21 pages, 3653 KB

Open AccessArticle

A 28 mK Resolution, −0.45 °C/+0.51 °C Inaccuracy Temperature Sensor Using Dual-Comparator Architecture and Logic-Controlled Counting Method

by Yubin Xu, Tongyu Luo and Lin Peng

Micromachines 2025, 16(8), 947; https://doi.org/10.3390/mi16080947 - 18 Aug 2025

Viewed by 610

Abstract

This paper presents an all-CMOS temperature sensor with low power consumption, wide temperature range, and high precision in a 180 nm CMOS process. Based on the I–V characteristics of MOSFETs in the subthreshold region and the negative exponential biasing current generated by the [...] Read more.

This paper presents an all-CMOS temperature sensor with low power consumption, wide temperature range, and high precision in a 180 nm CMOS process. Based on the I–V characteristics of MOSFETs in the subthreshold region and the negative exponential biasing current generated by the self-bootstrapped bias circuit, the proposed temperature-sensing front-end produces CTAT and PTAT voltages with high linearity and high sensitivity. The voltage-to-time converter (VTC) adopts a dual-comparator architecture to expand the time interval for improving resolution. The control logic unit is designed to count only within the time interval, eliminating interference during low-level periods and enhancing the accuracy of temperature measurement. The implemented sensor achieves an inaccuracy of −0.45 °C/+0.51 °C (

3 σ

) from −40 °C to 130 °C after a two-point calibration with a resolution of 28 mK and consumes 503 nW at 27 °C when operating at 1 V, with an FoM of 7.9 pJ·K². Full article

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14 pages, 6681 KB

Open AccessArticle

An Efficient Manufacturing Method for Silicon Carbide Crystals in Polymers Based on a Multiscale Simulation-Driven Approach

by Jia Wang, Caiqin Jia, Heming Sun and Ye Tian

Micromachines 2025, 16(8), 946; https://doi.org/10.3390/mi16080946 - 18 Aug 2025

Viewed by 392

Abstract

The pyrolysis of polydimethylsiloxane (PDMS) for silicon carbide (SiC) fabrication endows precursor materials with exceptional microstructural controllability and complex geometry retention capability, rendering it widely applicable in flexible electronic packaging and microscale complex-structured heat exchangers. Nevertheless, the widespread adoption of pyrolytic SiC has [...] Read more.

The pyrolysis of polydimethylsiloxane (PDMS) for silicon carbide (SiC) fabrication endows precursor materials with exceptional microstructural controllability and complex geometry retention capability, rendering it widely applicable in flexible electronic packaging and microscale complex-structured heat exchangers. Nevertheless, the widespread adoption of pyrolytic SiC has been constrained by the low yield and process complexity inherent to conventional pyrolysis methods. In response, we developed a multiscale simulation framework integrating macroscopic thermal distribution with microscopic chemical reaction kinetics. The secondary pyrolysis protocol, designed based on simulation results, enhanced the SiC yield from <25% (conventional methods) to 79.2% while simultaneously improving crystalline quality. This simulation framework not only provides theoretical guidance for optimizing laser direct writing pyrolysis, but the proposed secondary ablation strategy also significantly expands the application potential of SiC-PDMS systems in device fabrication. Full article

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17 pages, 5949 KB

Open AccessArticle

Fabrication and Dose–Response Simulation of Soft Dual-Sided Deep Brain Stimulation Electrode

by Jian Zhang, Bei Tong, Changmao Ni, Dengfei Yang, Guoting Fu and Li Huang

Micromachines 2025, 16(8), 945; https://doi.org/10.3390/mi16080945 - 18 Aug 2025

Viewed by 740

Abstract

A 16-channel dual-sided flexible electrode based on a polyimide substrate was designed and fabricated using micro-electromechanical system (MEMS) technology. The electrode exhibited an average impedance of 5.9 kΩ at 1 kHz and a charge storage capacity (CSC) of 10.63 mC/cm². Concurrently, [...] Read more.

A 16-channel dual-sided flexible electrode based on a polyimide substrate was designed and fabricated using micro-electromechanical system (MEMS) technology. The electrode exhibited an average impedance of 5.9 kΩ at 1 kHz and a charge storage capacity (CSC) of 10.63 mC/cm². Concurrently, a three-dimensional finite element model incorporating electrical stimulation and micromotion-induced damage was established. The simulation results demonstrated that the implantation trauma caused by the bilateral electrode was significantly lower compared with silicon-based and cylindrical electrodes, while also enabling directional stimulation. Furthermore, leveraging the design of experiments (DOE) methodology, a multivariate regression model was developed to investigate the influence of key stimulation parameters—namely, current amplitude, frequency, and pulse width—on the volume of tissue activated (VTA). The results indicated that the regression model provided accurate predictions of VTA (R² = 0.912). Among the parameters, current amplitude and pulse width exerted a statistically significant influence on VTA size (p < 0.001), whereas the effect of frequency was comparatively minor (p = 0.387 > 0.05). This study presents the first successful fabrication and comprehensive dose–response analysis of a flexible bilateral DBS electrode. Its attributes of low implantation trauma, multi-channel capability, and directional stimulation offer a novel paradigm for precise neuromodulation. Additionally, the established stimulation parameter–VTA response model provides a robust theoretical foundation for optimizing therapeutic parameters in subsequent clinical applications. Full article

(This article belongs to the Special Issue Flexible and Wearable Electronics for Biomedical Applications)

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12 pages, 3502 KB

Open AccessArticle

Investigation on the Interfacial Delamination of Glass Substrate Packaging Using Cohesive Zone Models

by Tianzuo Qin, Wen Yang, Qiqin Wei, Zhangsen Cen, Jianquan Chen, Yi Xie, Huiping Tang and Daoguo Yang

Micromachines 2025, 16(8), 944; https://doi.org/10.3390/mi16080944 - 18 Aug 2025

Viewed by 516

Abstract

This study aligns with the development trend of glass substrate packaging. The research aims to analyze the delamination of the substrate–adhesive layer-chip trilayer structure in packaging through experimental testing to obtain interface strength parameters. Subsequently, an iterative process combining experiments and simulations was [...] Read more.

This study aligns with the development trend of glass substrate packaging. The research aims to analyze the delamination of the substrate–adhesive layer-chip trilayer structure in packaging through experimental testing to obtain interface strength parameters. Subsequently, an iterative process combining experiments and simulations was applied to establish a cohesive zone model characterizing crack initiation and propagation. Finally, reliability analysis of the packaging structure was conducted. The results indicate that the load–displacement curves during sample loading can be experimentally acquired, enabling the determination of critical load values triggering interface delamination. The specific locations of delamination within the packaging structure are also clearly observed. Through simulation fitting, cohesive parameters reflecting interface strength are obtained, which serve as the basis for evaluating interface delamination fractures. Furthermore, applying the calibrated cohesive parameters to the established glass substrate model, simulation analysis evaluates delamination risks under thermal conditions. Full article

(This article belongs to the Special Issue Advanced Packaging for Microsystem Applications, 3rd Edition)

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5 pages, 176 KB

Open AccessEditorial

Editorial for This Special Issue on Energy Conversion Materials and Devices and Their Applications

by Bin Liu, Yaling Wang and Lei Liu

Micromachines 2025, 16(8), 943; https://doi.org/10.3390/mi16080943 - 17 Aug 2025

Viewed by 343

Abstract

The global push toward sustainable energy, driven by soaring energy demands, escalating environmental concerns, and urgent climate challenges, has catalyzed remarkable advancements in energy conversion materials and devices [...] Full article

(This article belongs to the Special Issue Energy Conversion Materials/Devices and Their Applications)

17 pages, 5923 KB

Open AccessArticle

Study of an Ultra-Low-Frequency Inertial Vibration Energy Harvester with a Frequency Up-Conversion Approach

by Jun Chen, Jieliang Xu, Mingjie Guan, Ziqiao Shen and Zilong Cheng

Micromachines 2025, 16(8), 942; https://doi.org/10.3390/mi16080942 - 16 Aug 2025

Viewed by 452

Abstract

For ultra-low-frequency vibration applications, this study focuses on a piezoelectric energy harvesting system with a spring mass system, utilizing magnetic plucking to up-convert the frequency. The proposed spring mass system includes a spring, a magnet mass with a guide rail, and a fixed [...] Read more.

For ultra-low-frequency vibration applications, this study focuses on a piezoelectric energy harvesting system with a spring mass system, utilizing magnetic plucking to up-convert the frequency. The proposed spring mass system includes a spring, a magnet mass with a guide rail, and a fixed pulley. The spring mass system responds to external ultra-low-frequency excitation and transfers the vibration to the piezoelectric cantilever beam through the magnets, achieving frequency up-conversion. The theoretical model of the designed piezoelectric energy harvesting system is established, and the effects of magnetic forces and potential energy between the magnets are analyzed. Numerical analysis and experimental studies demonstrate that the proposed piezoelectric energy harvesting system can efficiently achieve frequency up-conversion and generate a higher output power under the conditions of sinusoidal excitation at a frequency of 1 Hz and an amplitude of 40 mm. The system exhibits its highest power output with a magnetic distance of 15 mm, resulting in a maximum output power of 57.35 μW. Finally, to verify the performance of the designed energy harvester in low-velocity water flow, a series of underwater experiments were carried out. The results show that the designed harvester can generate an output power of 23.73 μW with optimal resistance of 250 kΩ at a flow rate of 0.371 m/s. The designed structure is well suited for energy harvesting in flow-induced vibration in low-velocity water flow. Full article

(This article belongs to the Section E：Engineering and Technology)

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11 pages, 1701 KB

Open AccessArticle

Design Strategies for Optimized Bulk-Linearized MOS Pseudo-Resistor

by Lorenzo Benatti, Tommaso Zanotti and Francesco Maria Puglisi

Micromachines 2025, 16(8), 941; https://doi.org/10.3390/mi16080941 - 16 Aug 2025

Viewed by 499

Abstract

The bulk linearization technique is a design strategy used to extend the linear region of a metal oxide semiconductor field effect transistor (MOSFET) by increasing its saturation voltage through a composite structure and a gate biasing circuit. This allows us to develop compact [...] Read more.

The bulk linearization technique is a design strategy used to extend the linear region of a metal oxide semiconductor field effect transistor (MOSFET) by increasing its saturation voltage through a composite structure and a gate biasing circuit. This allows us to develop compact and flexible pseudo-resistor elements for integrated circuit designs. In this paper we propose a new simple yet effective design approach, focused on the biasing circuit, that optimizes area, offset, and power consumption without altering the design complexity of the original solution. Post-layout simulations verify the presented design strategy, which is then applied for designing a band-pass filter for neural action potential acquisition. Results of harmonic distortion and noise analysis strengthen the validity of the proposed strategy. Full article

(This article belongs to the Special Issue Celebration of 60th Anniversary of Moore's Law: The Significant Milestone in Micromachines)

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23 pages, 7663 KB

Open AccessFeature PaperEditor’s ChoiceReview

Advances in 3D Printing: Microfabrication Techniques and Forming Applications

by Di Pan, Fanghui Jia, Muyuan Zhou, Hao Liu, Jingru Yan, Lisong Zhu, Ming Yang and Zhengyi Jiang

Micromachines 2025, 16(8), 940; https://doi.org/10.3390/mi16080940 - 15 Aug 2025

Viewed by 570

Abstract

Stainless steel is essential in high-performance industries due to its strength, corrosion resistance, and biocompatibility. However, conventional manufacturing methods limit material efficiency, design complexity, and customization. Additive manufacturing (AM) has emerged as a powerful alternative, enabling the production of stainless-steel components with complex [...] Read more.

Stainless steel is essential in high-performance industries due to its strength, corrosion resistance, and biocompatibility. However, conventional manufacturing methods limit material efficiency, design complexity, and customization. Additive manufacturing (AM) has emerged as a powerful alternative, enabling the production of stainless-steel components with complex geometries, tailored microstructures, and integrated functionalities. Key AM methodologies, including laser powder bed fusion (L-PBF), binder jetting, and directed energy deposition (DED), are evaluated for their effectiveness in producing stainless-steel components with optimal performance characteristics. This review highlights innovations in stainless-steel AM, focusing on microfabrication, multi-material approaches, and post-processing strategies such as heat treatment, hot isostatic pressing (HIP), and surface finishing. It also examines the impact of process parameters on microstructure, mechanical anisotropy, and defects. Emerging trends include AM-specific alloy design, functionally graded structures, and AI-based control. Applications span biomedical implants, micro-tooling, energy systems, and automotive parts, with emphasis on microfabrication for biomedical micromachines and precision microforming. Full article

(This article belongs to the Special Issue Innovations in 3D Printing Technologies: From Microfabrication to Functional Applications)

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13 pages, 3078 KB

Open AccessArticle

Effect of Clear Corneal Incisions via Femtosecond Laser Versus Manual Incisions on Corneal Aberrations in Cataract Surgery

by Vesko Onov, Gabriele Thumann, Martina Kropp, Zeljka Cvejic, Filip Slezak and Bojan Pajic

Micromachines 2025, 16(8), 939; https://doi.org/10.3390/mi16080939 - 15 Aug 2025

Viewed by 580

Abstract

This study aimed to evaluate whether clear corneal incisions (CCIs) created with the FEMTO LDV Z8 femtosecond laser during cataract surgery are non-inferior to manual CCIs in terms of surgically induced astigmatism (SIA) and higher-order aberrations (HOAs). A total of 78 cataract patients [...] Read more.

This study aimed to evaluate whether clear corneal incisions (CCIs) created with the FEMTO LDV Z8 femtosecond laser during cataract surgery are non-inferior to manual CCIs in terms of surgically induced astigmatism (SIA) and higher-order aberrations (HOAs). A total of 78 cataract patients were randomly assigned to two groups: 38 eyes underwent femtosecond laser-assisted cataract surgery (FLACS), and 40 eyes underwent conventional manual cataract surgery (CCS). Preoperative and six-week postoperative SIA, HOAs, and all topographic and refractive data were analysed for both groups. FLACS-generated CCIs demonstrated equivalence to manual CCIs. The mean SIA was 0.44 ± 0.27 dioptres (D) in the FLACS group and 0.58 ± 0.46 D in the CCS group (p = 0.18), with lower variability in the FLACS group. The root mean square (RMS) corneal HOA at six weeks was 0.69 ± 0.17 µm in the FLACS group and 0.80 ± 0.56 µm in the CCS group (p > 0.05). These results confirm the efficacy, reproducibility, and safety of FLACS. Although not statistically significant, FLACS induced numerically lower SIA values and less variability than manual CCIs. Both groups were comparable in terms of HOAs, though higher mean values and variability were observed in the CCS group. Full article

(This article belongs to the Special Issue Laser Micro/Nano Fabrication, Second Edition)

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9 pages, 2036 KB

Open AccessArticle

Design of a Dual-Band Low-Noise Amplifier with a Novel Matching Structure

by Mingwen Zhang, Zhiqun Cheng, Tingwei Gong, Bangjie Zheng, Zhiwei Zhang and Xuefei Xuan

Micromachines 2025, 16(8), 938; https://doi.org/10.3390/mi16080938 - 15 Aug 2025

Viewed by 402

Abstract

This paper proposes a method for designing a dual-band low-noise amplifier (DB-LNA) using a new improved complex impedance dual-band transformer (IDBT). This complex IDBT is composed of parallel-coupled lines and two sections of series microstrip lines. The parallel-coupled lines are used to complete [...] Read more.

This paper proposes a method for designing a dual-band low-noise amplifier (DB-LNA) using a new improved complex impedance dual-band transformer (IDBT). This complex IDBT is composed of parallel-coupled lines and two sections of series microstrip lines. The parallel-coupled lines are used to complete the transformation from complex impedances at two different frequencies to a pair of conjugate complex impedances, meanwhile eliminating the need for DC blocking capacitors. The transformation to real impedances is achieved by series microstrip lines at dual frequency points. A single-stage DB-LNA was designed using the BFP840ESD transistor in combination with the proposed IDBT. The fabrication and testing of the Printed Circuit Board (PCB) were then completed. The measured results of the proposed 2.4/5.5 GHz DB-LNA show an S21 parameter of 20.3/14.7 dB, an S11 of −29.8/−20.3 dB, an S22 of −15.2/−16.4 dB, and a noise figure (NF) of 1.6/1.6 dB. The whole DB-LNA has a simple structure, low cost, and excellent performance and is easy to tune. Full article

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12 pages, 11986 KB

Open AccessArticle

Design of Long-Wave Fully Polarized HgCdTe Photodetector Based on Silicon Metasurface

by Bo Cheng, Xiaoming Wang, Yuxiao Zou, Guofeng Song, Kunpeng Zhai and Xiaojun Wang

Micromachines 2025, 16(8), 937; https://doi.org/10.3390/mi16080937 - 14 Aug 2025

Viewed by 446

Abstract

Polarization-sensitive photodetection is critical for advanced optical systems, yet achieving simultaneous high-fidelity recognition of the circularly polarized (CP) and linearly polarized (LP) light with compact designs remains challenging. Here, we use COMSOL 5.6 software to demonstrate a silicon metasurface-integrated MCT photodetector that resolves [...] Read more.

Polarization-sensitive photodetection is critical for advanced optical systems, yet achieving simultaneous high-fidelity recognition of the circularly polarized (CP) and linearly polarized (LP) light with compact designs remains challenging. Here, we use COMSOL 5.6 software to demonstrate a silicon metasurface-integrated MCT photodetector that resolves both CP and LP signals through a single ultrathin platform. The device deciphers LP states via four orientation-specific linear gratings for differential detection, while chiral symmetric silicon nanostructures enable direct CP discrimination with an exceptional extinction ratio of 30 dB. The proposed architecture combines two breakthroughs: (1) superior polarization reconstruction capability, achieved via the synergy of grating-induced polarization selectivity and chiral near-field enhancement, and (2) a fabrication-simplified process that eliminates multilayer stacking or complex alignment steps. This work establishes a new paradigm for miniaturized, high-performance polarization optics, with potential applications in polarization imaging, quantum communication, and hyperspectral sensing. Full article

(This article belongs to the Special Issue Photonic and Optoelectronic Devices and Systems, Third Edition)

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20 pages, 5906 KB

Open AccessArticle

Multi-Objective Optimization of Surface Roughness, Cutting Force, and Temperature in Ultrasonic-Vibration-Assisted Milling of Titanium Alloy

by Gaofeng Hu, Yanjie Lu, Shengming Zhou, Xin He, Fenghui Zhang, Pengchao Zhu, Mingshang Wang, Taowei Tan and Guangjun Chen

Micromachines 2025, 16(8), 936; https://doi.org/10.3390/mi16080936 - 14 Aug 2025

Viewed by 387

Abstract

Titanium alloys (Ti-6Al-4V) are widely used in the aerospace field. However, as a typical difficult-to-machine material, titanium alloys have a low thermal conductivity, a high chemical activity, and a significant adiabatic shear effect. In conventional milling (CM), the temperature in the cutting zone [...] Read more.

Titanium alloys (Ti-6Al-4V) are widely used in the aerospace field. However, as a typical difficult-to-machine material, titanium alloys have a low thermal conductivity, a high chemical activity, and a significant adiabatic shear effect. In conventional milling (CM), the temperature in the cutting zone rises sharply, leading to tool adhesion, rapid wear, and damage to the workpiece surface. This article systematically investigated the influence of process parameters on the surface roughness, cutting force, and cutting temperature in the ultrasonic-vibration-assisted milling (UAM) process of titanium alloys, based on which multi-objective optimization process of the milling process parameters was conducted, by utilizing the grey relational analysis method. An orthogonal experiment with four factors and four levels was conducted. The effects of various process parameters on the surface roughness, cutting force, and cutting temperature were systematically analyzed for both UAM and CM. The grey relational analysis method was employed to transform the optimization problem of multiple process target parameters into a single-objective grey relational degree optimization problem. The optimized parameter combination was as follows: an ultrasonic amplitude of 6 μm, a spindle speed of 6000 rpm, a cutting depth of 0.20 mm, and a feed rate of 200 mm/min. The experimental results indicated that the surface roughness Sa was 0.268 μm, the cutting temperature was 255.39 °C, the cutting force in the X direction (FX) was 5.2 N, the cutting force in the Y direction (FY) was 7.9 N, and the cutting force in the Z direction (FZ) was 6.4 N. The optimization scheme significantly improved the machining quality and reduced both the cutting forces and the cutting temperature. Full article

(This article belongs to the Section E：Engineering and Technology)

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Micromachines, Volume 16, Issue 8 (August 2025) – 129 articles

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