Micromachines

Research

Jump to: Review

15 pages, 6126 KiB

Open AccessArticle

Investigations into Capillary Forces and Capillary Rise in a Three-Finger Microgripper and a Plate: Numerical Simulations and Experimental Validation

by Zhi Xu, Zenghua Fan, Jun Gao, Kun Zhang and Xiang Zhang

Micromachines 2024, 15(12), 1459; https://doi.org/10.3390/mi15121459 - 29 Nov 2024

Viewed by 367

Abstract

The assembly and position adjustment of micro-components have wide applications in micro-electromechanical systems, wafer packaging and biomedicine. However, current single-finger microgrippers only allow for the pickup and release of micro-components. In the present study, a three-finger capillary microgripper was developed to pick up, [...] Read more.

The assembly and position adjustment of micro-components have wide applications in micro-electromechanical systems, wafer packaging and biomedicine. However, current single-finger microgrippers only allow for the pickup and release of micro-components. In the present study, a three-finger capillary microgripper was developed to pick up, release and adjust the position of micro-components. The capillary force and the capillary rise generated by the capillary bridge were investigated by simulation and experiments. A simulation model was set up by the minimum energy method. On the established experimental platform, capillary forces were measured at different separation distances. When the volume was 0.9 μL, the maximum capillary forces gained from the capillary bridge model and experiments were 95.2 μN and 96.0 μN, respectively. A comparison of the capillary bridge models and the experimental results of the capillary forces demonstrate the reliability of the capillary bridge models. The influences of various parameters were investigated in detail by the capillary bridge model. The results demonstrate that when the side of the probe is hydrophilic, the variations in the capillary force with various factors such as separation distance and capillary bridge volume is non-monotonic, which is caused by the restriction of the probe edge. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

12 pages, 3235 KiB

Open AccessArticle

Dynamic Acoustic Holography: One-Shot High-Precision and High-Information Methodology

by Zhaoxi Li, Yiheng Yang, Qi Lu, Xiongwei Wei, Chenxue Hou, Yi Quan, Xiaozhou Lü, Weimin Bao, Yintang Yang and Chunlong Fei

Micromachines 2024, 15(11), 1316; https://doi.org/10.3390/mi15111316 - 29 Oct 2024

Viewed by 715

Abstract

Acoustic holography technology is widely used in the field of ultrasound due to its capability to achieve complex acoustic fields. The traditional acoustic holography method based on single-phase holograms is limited due to its inability to complete acoustic field control with high dynamics [...] Read more.

Acoustic holography technology is widely used in the field of ultrasound due to its capability to achieve complex acoustic fields. The traditional acoustic holography method based on single-phase holograms is limited due to its inability to complete acoustic field control with high dynamics and accuracy. Here, we propose a method for constructing an acoustic holographic model, introducing an ultrasonic array to provide dynamic amplitude control degrees of freedom, and combining the dynamically controllable ultrasonic array and high-precision acoustic hologram to achieve the highest acoustic field accuracy and dynamic range. This simulation method has been proven to be applicable to both simple linear patterns and complex surface patterns. Moreover, it is possible to reconstruct the degree of freedom of the target plane amplitude effectively and achieve a breakthrough in high information content. This high-efficiency acoustic field control capability has potential applications in ultrasound imaging, acoustic tweezers, and neuromodulation. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

13 pages, 4206 KiB

Open AccessArticle

Physics-Based Artificial Neural Network Assisting in Extracting Transient Properties of Extrinsically Triggering Photoconductive Semiconductor Switches

by Zhong Zheng, Huiyong Hu, Yutian Wang, Tianlong Zhao, Qian Sun and Hui Guo

Micromachines 2024, 15(8), 1003; https://doi.org/10.3390/mi15081003 - 1 Aug 2024

Viewed by 812

Abstract

In this paper, a physics-based ANN assisting method for extracting transient properties of extrinsically triggering photoconductive semiconductor switches (ET-PCSSs) is proposed. It exploits the nonlinear mapping of ANN between transient current (input) and doping concentration (output). According to the basic laws of photoelectric [...] Read more.

In this paper, a physics-based ANN assisting method for extracting transient properties of extrinsically triggering photoconductive semiconductor switches (ET-PCSSs) is proposed. It exploits the nonlinear mapping of ANN between transient current (input) and doping concentration (output). According to the basic laws of photoelectric device operating, two types of ANN models are constructed by gaussian and polynomial fitting. The mean absolute error (MAE) of forecasting transient photocurrent can be less than 10 A under low triggering optical powers, which verifies the feasibility of ANN assisting TCAD applied to PCSSs. The results are comparable to computation by Mixed-Mode simulation, yet even thousands of seconds of CPU runtime cost are saved in every period. To improve the robustness of the Poly-ANN predictor, Bayesian optimization (BO) is implemented for minimizing the curl deviation of photocurrent-time curves. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

14 pages, 2717 KiB

Open AccessArticle

Characterizing Acoustic Behavior of Silicon Microchannels Separated by a Porous Wall

by Mehrnaz Hashemiesfahan, Jo Wim Christiaens, Antonio Maisto, Pierre Gelin, Han Gardeniers and Wim De Malsche

Micromachines 2024, 15(7), 868; https://doi.org/10.3390/mi15070868 - 30 Jun 2024

Viewed by 1171

Abstract

Lateral flow membrane microdevices are widely used for chromatographic separation processes and diagnostics. The separation performance of microfluidic lateral membrane devices is determined by mass transfer limitations in the membrane, and in the liquid phase, mass transfer resistance is dependent on the channel [...] Read more.

Lateral flow membrane microdevices are widely used for chromatographic separation processes and diagnostics. The separation performance of microfluidic lateral membrane devices is determined by mass transfer limitations in the membrane, and in the liquid phase, mass transfer resistance is dependent on the channel dimensions and transport properties of the species separated by the membrane. We present a novel approach based on an active bulk acoustic wave (BAW) mixing method to enhance lateral transport in micromachined silicon devices. BAWs have been previously applied in channels for mixing and trapping cells and particles in single channels, but this is, to the best of our knowledge, the first instance of their application in membrane devices. Our findings demonstrate that optimal resonance is achieved with minimal influence of the pore configuration on the average lateral flow. This has practical implications for the design of microfluidic devices, as the channels connected through porous walls under the acoustic streaming act as 760 µm-wide channels rather than two 375 µm-wide channels in the context of matching the standing pressure wave criteria of the piezoelectric transducer. However, the roughness of the microchannel walls does seem to play a significant role in mixing. A roughened (black silicon) wall results in a threefold increase in average streaming flow in BAW mode, suggesting potential avenues for further optimization. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

13 pages, 4854 KiB

Open AccessArticle

A Novel EWOD Platform for Freely Transporting Droplets in Double and Single-Plate Structures

by Yii-Nuoh Chang, Ting-Rui Huang and Da-Jeng Yao

Micromachines 2024, 15(6), 797; https://doi.org/10.3390/mi15060797 - 17 Jun 2024

Viewed by 3690

Abstract

This study developed a novel dielectric wetting microfluidic operation platform combining parallel-plate and coplanar-plate regions with a curved surface structure as the connection structure. With the new electrowetting on dielectric (EWOD) platform, “droplet pull-out” has been successfully achieved and viewed as an essential [...] Read more.

This study developed a novel dielectric wetting microfluidic operation platform combining parallel-plate and coplanar-plate regions with a curved surface structure as the connection structure. With the new electrowetting on dielectric (EWOD) platform, “droplet pull-out” has been successfully achieved and viewed as an essential new operation for microfluidics with the dielectric wetting technique. The EWOD system is divided into a PDMS substrate top plate and an indium tin oxide (ITO) glass substrate as a bottom layer on this chip. In the parallel-plate region, the droplets can be generated and transported through the square parallel electrodes; in the single-plate area, the droplets can be pulled out from the parallel structure, transported and mixed through the common grounded coplanar electrodes. In dielectric wetting performance testing, coplanar electrodes can apply a maximum driving force of 31.22 µN to DI water and 13.38 µN to propylene carbonate (PC). This driving force is sufficient to detach the sample from the top cover and pull the sub-droplet from the parallel plate structure for DI water, PC and polyethylene glycol diacrylate (PEGDA) buffer. The novel EWOD system also possesses the advantage of precise volume control for liquid samples; the volume error of the generated droplet can be controlled within 0.1% to 2%. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

20 pages, 40920 KiB

Open AccessArticle

Digital Eddy Current Detection Method Based on High-Speed Sampling with STM32

by Xiong Cao, Erlong Li, Zilan Yuan and Kaituo Zheng

Micromachines 2024, 15(6), 775; https://doi.org/10.3390/mi15060775 - 11 Jun 2024

Cited by 1 | Viewed by 983

Abstract

The electromagnetic eddy current non-destructive testing system enables the non-destructive analysis of surface defect information on tested materials. Based on the principles of eddy current detection, this paper presents a digital eddy current detection method using high-speed sampling based on STM32. A differential [...] Read more.

The electromagnetic eddy current non-destructive testing system enables the non-destructive analysis of surface defect information on tested materials. Based on the principles of eddy current detection, this paper presents a digital eddy current detection method using high-speed sampling based on STM32. A differential eddy current coil is used as the detection probe, and the combination of a differential bridge and a differential amplifier circuit helps to reduce common-mode noise interference. The detection signal is collected via an STM32-based acquisition circuit and transmitted to the host computer through Ethernet for digital demodulation processing. The host computer performs operations such as smoothing averaging, sinusoidal fitting, and outlier removal to extract the amplitude and phase of the detection signal. The system also visually displays the condition of the tested object’s surface in real time through graphical visualization. Testing showed that this system can operate at frequencies up to 8.84 MHz and clearly identify defects as narrow as 1 mm on the surface of the tested steel plate. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

17 pages, 4576 KiB

Open AccessArticle

A Wearable Fingertip Force Feedback Device System for Object Stiffness Sensing

by Changcheng Wu, Jianli Ren, Qingqing Cao, Zeran Yue, Ting Fang and Aiguo Song

Micromachines 2024, 15(6), 693; https://doi.org/10.3390/mi15060693 - 24 May 2024

Viewed by 1207

Abstract

Virtual reality technology brings a new experience to human-computer interaction, while wearable force feedback devices can enhance the immersion of users in interaction. This paper proposes a wearable fingertip force feedback device that uses a tendon drive mechanism, with the aim of simulating [...] Read more.

Virtual reality technology brings a new experience to human-computer interaction, while wearable force feedback devices can enhance the immersion of users in interaction. This paper proposes a wearable fingertip force feedback device that uses a tendon drive mechanism, with the aim of simulating the stiffness characteristics of objects within virtual scenes. The device adjusts the rotation angle of the torsion spring through a DC motor, and then uses a wire to convert the torque into a feedback force at the user’s index fingertips, with an output force of up to 4 N and a force change rate of up to 10 N/s. This paper introduces the mechanical structure and design process of the force feedback device, and conducts a mechanical analysis of the device to select the appropriate components. Physical and psychological experiments are conducted to comprehensively evaluate the device’s performance in conveying object stiffness information. The results show that the device can simulate different stiffness characteristics of objects, and users can distinguish objects with different stiffness characteristics well when wearing the force feedback device and interacting with the three-dimensional virtual environments. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

Review

Jump to: Research

20 pages, 15185 KiB

Open AccessReview

Comprehensive Review of FinFET Technology: History, Structure, Challenges, Innovations, and Emerging Sensing Applications

by Koosha Karimi, Ali Fardoost and Mehdi Javanmard

Micromachines 2024, 15(10), 1187; https://doi.org/10.3390/mi15101187 - 25 Sep 2024

Viewed by 4987

Abstract

The surge in demand for 3D MOSFETs, such as FinFETs, driven by recent technological advances, is explored in this review. FinFETs, positioned as promising alternatives to bulk CMOS, exhibit favorable electrostatic characteristics and offer power/performance benefits, scalability, and control over short-channel effects. Simulations [...] Read more.

The surge in demand for 3D MOSFETs, such as FinFETs, driven by recent technological advances, is explored in this review. FinFETs, positioned as promising alternatives to bulk CMOS, exhibit favorable electrostatic characteristics and offer power/performance benefits, scalability, and control over short-channel effects. Simulations provide insights into functionality and leakage, addressing off-current issues common in narrow band-gap materials within a CMOS-compatible process. Multiple structures have been introduced for FinFETs. Moreover, some studies on the fabrication of FinFETs using different materials have been discussed. Despite their potential, challenges like corner effects, quantum effects, width quantization, layout dependencies, and parasitics have been acknowledged. In the post-planar CMOS landscape, FinFETs show potential for scalability in nanoscale CMOS, which leads to novel structures for them. Finally, recent developments in FinFET-based sensors are discussed. In a general view, this comprehensive review delves into the intricacies of FinFET fabrication, exploring historical development, classifications, and cutting-edge ideas for the used materials and FinFET application, i.e., sensing. Full article

(This article belongs to the Special Issue Feature Papers of Micromachines in ‘Engineering and Technology’ 2024)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Feature Papers of Micromachines in ‘Engineering and Technology’ 2024

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issues

Published Papers (8 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI