Micromachines最新文献

{"title":"Predicting Impact Loads on Polymer Materials from Laser-Induced Cavitation Bubble Collapse Using Random Forest Regression.","authors":"Muhammad Farkhan Abdillah, Kazuaki Inaba","doi":"10.3390/mi17091083","DOIUrl":"10.3390/mi17091083","url":null,"abstract":"<p><p>Cavitation bubble collapse generates impact loads that can initiate surface damage and accelerate material degradation in hydraulic and fluid-handling systems. Predicting these loads remains challenging because the collapse response depends on nonlinear interactions among bubble dynamics, stand-off distance, and polymer mechanical, acoustic, and viscoelastic properties. This study developed machine-learning regression models to predict impact loads from laser-induced single-bubble collapse on polyethylene, polytetrafluoroethylene (PTFE), polyamide, and antistatic polyethylene terephthalate (antistatic PET). Experiments were performed using a pulsed Nd:YAG laser at energies of 12.5, 25, and 50 mJ and normalized stand-off distances of γ = 1-5, producing 180 measurements. Impact loads were measured using a force-calibrated PVDF sensor with material-specific calibration equations. Bubble radius was obtained from high-speed imaging, whereas collapse time was determined from the PVDF voltage-time response. Thirteen input variables were used to train linear, ridge, LASSO, multilayer perceptron, and random forest regressors with Bayesian optimization and grouped five-fold cross-validation. Random forest regression achieved the best performance, with RMSE=0.6820N, MAE=0.5339N, R2=0.9168, and MAPE=12.44%. SHAP analysis identified collapse time, acoustic impedance, and loss modulus as dominant predictors. The model is therefore suitable for trend prediction within the tested experimental domain.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609618/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved ASHCPWM with Reduced IGBT Switching Actions and Kalman Filter-Based Zero-Sequence Suppression for Open-End Winding PMSM Drives.","authors":"Yu Zhang, Mingzhe Qu, Hongjia Xie, Yang Xia, Liangxing Hu","doi":"10.3390/mi17091081","DOIUrl":"10.3390/mi17091081","url":null,"abstract":"<p><p>To improve the dc-bus voltage utilization while reducing the commutation burden of an insulated gate bipolar transistor (IGBT)-based open-end winding permanent magnet synchronous motor (OEW-PMSM) drive, this paper proposes an improved alternate sub-hexagonal center PWM (ASHCPWM) strategy. The drive employs two three-phase IGBT inverters sharing a common dc bus. Since the turn-off energy of an IGBT is strongly affected by its switching frequency, ASHCPWM alternately clamps one inverter and reduces the number of switching transitions. The resulting common-mode voltage mismatch, together with the dead-time voltage error required to prevent shoot-through in the IGBT bridge legs, nevertheless produces significant zero-sequence current and additional semiconductor current stress. A mathematical model of the zero-sequence voltage is therefore established, and a common-mode voltage compensation method is combined with an improved Kalman-filter-based harmonic extraction and closed-loop suppression strategy. The switching performance of the modulation is evaluated by counting the switching transitions of the twelve IGBTs and by comparing the zero-sequence current and phase-current spectra. Experiments on a 10 kHz prototype demonstrate that the proposed method substantially reduces zero-sequence harmonics while retaining the reduced-switching characteristic of the original ASHCPWM.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609429/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlling the Mixing Performance of Passive Micromixers with Variable Section Units.","authors":"Lijun Yang, Yu Hang, Renjie Liu, Qilin Jiang, Zongan Li, Jun Hong, Ye Wu","doi":"10.3390/mi17091082","DOIUrl":"10.3390/mi17091082","url":null,"abstract":"<p><p>Changing the structures of microchannels has become an effective strategy for improving the mixing performance of passive micromixers. In this study, we propose a novel micromixer with variable section units through changing the geometric parameters including the type, the position, the number, and the ratio of the variable section units. The effects of these geometric parameters on the mixing performance were numerically investigated and parametrically compared. The results showed that the type of Gra channel, the initial position, a number of 4, and the ratio of 1:4 should be selected. With this selected configuration, the mixing efficiency of the micromixer can be significantly enhanced, with the mixing index exceeding 0.96 at a Reynolds number of 100. These findings demonstrate an effective design strategy for developing passive micromixers.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609589/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving Long-Range Intramolecular Proton Transfer-Further Molecular Design Using the Successful Molecular Switch 8-(Benzo[d]thiazol-2-yl)quinolin-7-ol (HQBT) as a Structural Model.","authors":"Daniela Nedeltcheva-Antonova, Nikoleta Kircheva, Silvia Angelova, Liudmil Antonov","doi":"10.3390/mi17091084","DOIUrl":"10.3390/mi17091084","url":null,"abstract":"<p><p>Proton cranes are single-molecule photoswitches with rotor and stator parts attached, where the switching event is based on a multi-step, long-range intramolecular proton transfer within the stator. The process of intramolecular motion makes such structures prototypes for machines at a nanomolecular level with broad potential applications as novel materials, necessitating a multifaceted approach to their investigation. Theoretical design of conjugated tautomeric proton cranes, using benzothiazole as a tautomeric rotor and a variety of tautomeric OH-containing heterocycles as possible stators, has been attempted by using density functional theory calculations in various environments. The shape of the ground-state potential energy surface has been used to estimate the suitability of possible proton cranes. A previously developed and studied proton crane, named <b>HQBT</b>, in which the benzothiazole rotor is attached to the eighth position of the quinoline-7-ol stator, has been used as a comparative example. The results indicate that under certain conditions, cinnolin-7-ol-based proton cranes could have practical applicability in non-polar media, where the performance of <b>HQBT</b> is not satisfactory.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609328/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a Three-Axis Piezoelectric Accelerometer with Wide Frequency, High Sensitivity and Low Cross-Axis Interference.","authors":"Po-Chun Chen, Ze-Wen Sun, Sheng-Yuan Chu, Cheng-Che Tsai","doi":"10.3390/mi17091080","DOIUrl":"10.3390/mi17091080","url":null,"abstract":"<p><p>A single-structure three-axis MEMS accelerometer often suffers from cross-axis interference, which leads to inaccurate sensitivity and makes it difficult to reliably assess the health condition of the measured object. In addition, achieving high sensitivity often comes at the cost of reduced bandwidth. Because few previous studies have addressed the cross-axis interference of such structures, this study presents the development and optimization of a structural three-axis MEMS piezoelectric accelerometer. A mathematical model was first established, followed by simulation and structural optimization to enhance sensitivity and minimize cross-axis interference while keeping the bandwidth nearly unchanged. This study proposes, for the first time, an improved structure that evolves the L-shaped accelerometer into a composite configuration consisting of a W-shaped cantilever and an additional four-bar proof mass, in order to enhance bandwidth and significantly reduce cross-axis interference. Generally, an increase in sensitivity leads to a reduction in bandwidth; however, by modifying the geometry of the proof mass, the proposed accelerometer achieves a substantial improvement in sensitivity while avoiding a significant loss of bandwidth. The implementation of a triaxial accelerometer can generally be achieved in three ways: using three single-axis accelerometers, realizing three axes through circuitry, or achieving three axes through structural design. Using three single-axis accelerometers results in large volume, heavy weight, and high cost. Circuit-based three-axis implementation cannot detect multi-axis forces simultaneously, whereas structural three-axis design is difficult to realize. This study focuses on designing a triaxial accelerometer based on a structural approach, optimizing it with reference to the most successful examples reported in the literature and progressively addressing the drawbacks of previous structures. First, trapezoidal beams are used instead of rectangular cantilever beams to increase bandwidth. Next, two additional cantilever beams are added to transfer the <i>Z</i>-axis sensitivity detection points to reduce cross-axis interference. Finally, the shape of the proof mass is designed to enhance the sensitivities along all three axes. The optimized accelerometer exhibits resonant frequencies of approximately 12.6 kHz, 31.6 kHz, and 11.8 kHz along the <i>X</i>-, <i>Y</i>-, and <i>Z</i>-axes, with corresponding sensitivities of 6.11, 5.44, and 8.85 mV/g, and cross-axis interference reduced to below 15%. The results demonstrate the achievement of a highly accurate and reliable three-axis MEMS piezoelectric accelerometer through structural design and optimization. The proposed design concept may also be beneficial for other piezoelectric-based sensor applications.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609040/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent Developments, Applications, and Future Prospects of Advanced Hearts-on-a-Chip.","authors":"Aerin Kang, Hayun Lee, Gurnho Park, Taehong Kim, Hyoju Kim, Timothy Park, Sydney Staley, Miriam Kang, Youngbok Abraham Kang","doi":"10.3390/mi17091079","DOIUrl":"10.3390/mi17091079","url":null,"abstract":"<p><p>Heart-on-a-chip (HoC) platforms represent a cutting-edge convergence of microfluidics and cellular biology, designed to imitate the complex physiological, electrical, and mechanical environments of a human heart. HoC devices are used to culture and observe cardiac cells in a highly customizable environment while allowing for real-time observations. However, current HoC systems face critical translational bottlenecks. Most notably, laboratory-grown cardiomyocytes consistently exhibit structural and functional immaturity and a lack of cellular complexity. This review evaluates recent engineering and biological strategies engineered to address these limitations. We dissect advancements in multicellular co-culture, biomimetic electrical/mechanical stimulation regimes, and microvascular fabrication techniques aimed at driving functional cell maturation. Finally, we highlight current cardiac model applications, existing challenges, and future perspectives.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609516/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved DC Characteristic Modeling and Small-Signal Investigation of GaN Schottky Barrier Diodes.","authors":"Chuangye Wang, Liyue Tang, Ao Zhang, Jiali Cheng, Caoyu Li, Shuman Mao, Yuehang Xu, Qi He, Tao Guo, Kai Wang, Chang Wu","doi":"10.3390/mi17091078","DOIUrl":"10.3390/mi17091078","url":null,"abstract":"<p><p>This paper presents a complete modeling flow for GaN Schottky barrier diodes (SBDs), encompassing parasitic parameter de-embedding, small-signal equivalent circuit extraction, and DC characteristic analysis. The open/short de-embedding method is adopted to extract the parasitic parameters of the Ground-Signal-Ground (GSG) pads. A bias-partitioning strategy is employed to extract the intrinsic small-signal parameters, and the depletion capacitance model is used to physically fit the C-V characteristics. The forward Direct Current (DC) conduction current is described by the thermionic emission model, while the reverse leakage is modeled using a piecewise approach: the Poole-Frenkel (PF) trap-assisted emission model is applied in the low-bias region, and a double-exponential decay empirical model is introduced in the high-bias region, achieving high-precision fitting over the full bias range (-100 V~3 V). More importantly, this paper identifies a significant discrepancy between the series resistance extracted from DC measurements and that from Radio Frequency (RF) measurements, and attributes it to the frequency dispersion effect induced by trap states. The study demonstrates that combining DC and high-frequency characterization not only enables the construction of an accurate modeling framework, but also reveals the trap-related physical mechanisms within the device.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609336/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomic-Scale Mechanisms of Ultrasonic-Assisted Ultra-Precision Cutting of W-Mo70 Alloy: Experimental Benchmarking and Molecular Dynamics Simulation.","authors":"Yonglin Min, Zhanjie Li, Gang Jin","doi":"10.3390/mi17091076","DOIUrl":"10.3390/mi17091076","url":null,"abstract":"<p><p>W-Mo70 alloys feature high hardness, a high melting point and poor machinability, resulting in large cutting loads and complex subsurface plastic deformation during ultra-precision machining. To reveal the atomic-scale mechanism by which ultrasonic elliptical vibration regulates material removal and defect evolution, three-dimensional molecular dynamics (MD) models of conventional cutting (CC) and ultrasonic elliptical vibration cutting (UEVC) were established with previously published ultra-precision turning experiments as the macroscopic benchmark. The material removal behavior, cutting force response, interfacial loading characteristics and dislocation evolution law were systematically analyzed. The results show that UEVC exhibits a reduction trend in the cycle-averaged main cutting force compared with CC, which is qualitatively consistent with the experimental trend. However, the reduction magnitude should not be directly compared with experimental results because of the significant differences in machining scale, cutting velocity, strain rate, and tool geometry between MD simulations and experiments. The average normal force remains nearly unchanged but exhibits a significant vibration-induced transient loading-unloading response. Under UEVC, dislocation evolution transforms from continuous accumulation under CC to transient activation at the high-load stage and defect reorganization during the unloading stage. This study reveals the atomic-scale mechanism of UEVC characterized by a vibration-induced transient loading-unloading response, interfacial unloading, defect reorganization and phase-dependent localized material removal, providing atomic-level theoretical support for subsurface defect regulation in ultra-precision cutting of difficult-to-machine W-Mo alloys.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13608907/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micromachined Edge Reflection Thin-Film SAW Resonator on LiNbO₃-on-SiC.","authors":"Yu-Hao Wang, Zhen-Hui Qin, Yi-Han He, Hao Yan, Nan-Xin Yu, Cheng-Zhe Cao, Hua-Yang Chen, Si-Yuan Yu, Yan-Feng Chen","doi":"10.3390/mi17091075","DOIUrl":"10.3390/mi17091075","url":null,"abstract":"<p><p>This work presents the design and experimental demonstration of a micromachined edge reflection thin-film surface acoustic wave (SAW) resonator on an X-cut LiNbO₃-on-SiC platform. Unlike conventional Bragg reflection resonators (BRRs), the demonstrated device employs etched free edges adjacent to the interdigital transducer (IDT) to provide lateral acoustic confinement without additional reflector arrays. Edge half electrodes are further used to tailor the lateral phase condition and suppress spurious modes. The representative Design I resonator exhibits an electromechanical coupling coefficient (<i>k_t</i>²) of 37.6% and a maximum Bode-Q of 712 at 4.64 GHz, corresponding to a figure of merit (FoM) of 267.7. Compared with BRR counterparts fabricated in the same batch, the ERR reduces the effective resonator footprint by approximately 27-37% while maintaining a comparable <i>k_t</i>². Measurements further show that the ERR exhibits a higher <i>Q</i> in most paired designs, thereby yielding an improved FoM. These results establish micromachined edge boundary engineering as an effective route toward reflector-less thin-film SAW resonators with reduced effective resonator footprints and high-Q coupling performance while also clarifying the fabrication-related trade-offs associated with etched free edge confinement.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609639/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation and Performance Investigation of Broadband Antireflection Coatings in the Visible and Near-Infrared Spectral Regions.","authors":"Zhaoxuan Zheng, Zaijin Li, Qi Wu, Fei Lin, Yishui Lin, Ganghuang Liu, Runhe Bai, Wei Luo, Dongxin Xu, Yi Qu","doi":"10.3390/mi17091077","DOIUrl":"10.3390/mi17091077","url":null,"abstract":"<p><p>A seven-layer broadband antireflection coating consisting of Al₂O₃, TiO₂, SiO₂, and MgF₂ was designed and deposited on both sides of K9 glass for the 400-1100 nm range. The deposition parameters for TiO₂ and SiO₂ single layers were optimized, and the measured optical constants were used in TFCalc to refine the multilayer design. Layer-specific thickness-tolerance analysis was performed to identify the layers requiring strict process control. The initially characterized double-sided coating showed an average transmittance of 98.72% over 400-1100 nm. Four samples prepared in one additional deposition batch exhibited closely matching transmittance spectra, indicating low sample-to-sample variation within that batch. Five-position profilometry indicated consistent total-thickness control. Cross-sectional scanning electron microscopy (SEM) revealed well-defined multilayer contrast without obvious cracking, and regional energy-dispersive X-ray spectroscopy (EDS) analysis detected the constituent elements of the coating. These results demonstrate a practical design-to-fabrication approach that combines process-specific optical constants with tolerance analysis, with potential applications in imaging systems, optical windows, and lidar.</p>","PeriodicalId":18508,"journal":{"name":"Micromachines","volume":"17 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13609015/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149062270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}