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Micromachines
Special Issues
Micro and Smart Devices and Systems
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Micro and Smart Devices and Systems

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "E：Engineering and Technology".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 44333

Special Issue Editors

Dr. Zebing Mao

E-Mail Website
Guest Editor
Department of Engineering Science and Mechanics, Shibaura Institute of Technology, 3-7-5, 02-C-25b Toyosu, Koto-ku, Tokyo 135-8548, Japan
Interests: functional fluids; soft actuators and sensors; Belousov–Zhabotinsky (BZ) gel; machining and MEMS; microfluidics
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Jin Xie

E-Mail Website
Guest Editor
The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
Interests: MEMS sensors and actuators; micromachined ultrasonic transducers; resonators
Special Issues, Collections and Topics in MDPI journals
Dr. Hong Ding

E-Mail Website
Guest Editor
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Interests: MEMS sensors; ultrasound; soft actuators; flexible electronics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Micro and smart devices and systems such as solid/fluidic actuators and sensors, flexible electronics, functional fluids, MEMS, microfluidics, wearable devices, self-actuation/sensing and self-power systems, self-oscillating and smart hydrogels, intelligent control systems, lens, origami batteries, and fuel cells, etc., are becoming popular in various fields of robotics, telecommunications, chemistry, and biology. In addition, these smart devices and systems help us to improve our quality of life and are beneficial for us in understanding insects and animals in nature. The above devices are made of either rigid or soft materials with special mechanical and electrical properties, which have a large influence on their robustness and stability and can show some intelligent and smart characteristics. However, it is not easy to fully understand their working principles and integrate several components to a smart and intelligent system. Accordingly, relevant topics for this Special Issue include but are not limited to:

  • Novel design, modeling, fabrication, and assembling of micro and smart devices and systems based on various actuation and sensing methods of electric, thermal, light, magnetic, chemical reaction, acoustic, etc.
  • Smart and intelligent soft solid and fluidic robots, actuators and sensors, microfluidics, batteries, etc.
  • Theories and modeling of complex nonlinear phenomena relating to the micro and smart devices and systems.
  • New developments and applications of all types of micro and smart devices and systems.

We look forward to receiving your submissions!

Dr. Zebing Mao
Prof. Dr. Jin Xie
Dr. Hong Ding
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • MEMS/NEMS
  • flexible actuators and sensors
  • self-actuation/sensing and self-power systems
  • fluidic systems
  • self-oscillating and smart hydrogels
  • intelligent control systems
  • smart devices

Related Special Issues

Published Papers (16 papers)

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Editorial

Jump to: Research, Review

6 pages, 214 KiB  
Editorial
Editorial for the Special Issue on Micro and Smart Devices and Systems
by Zebing Mao, Jin Xie and Hong Ding
Micromachines 2023, 14(1), 164; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010164 - 08 Jan 2023
Viewed by 958
Abstract
Micro and smart devices and systems are small, interconnected devices and systems that are designed to be highly functional, efficient, and convenient [...] Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)

Research

Jump to: Editorial, Review

18 pages, 2218 KiB  
Article
Efficient Modeling and Simulation of PMUT Arrays in Various Ambients
by Omer M. O. Abdalla, Gianluca Massimino, Alessandro Stuart Savoia, Fabio Quaglia and Alberto Corigliano
Micromachines 2022, 13(6), 962; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13060962 - 18 Jun 2022
Cited by 7 | Viewed by 2964
Abstract
This paper presents a numerical reduced-order modeling (ROM) approach for complex multi-layered arrays of piezoelectric micromachined ultrasonic transducers (PMUTs). The numerical modeling technique adopted to generate an array of PMUTs consisting of a considerable number of transducers allows for a large reduction in [...] Read more.
This paper presents a numerical reduced-order modeling (ROM) approach for complex multi-layered arrays of piezoelectric micromachined ultrasonic transducers (PMUTs). The numerical modeling technique adopted to generate an array of PMUTs consisting of a considerable number of transducers allows for a large reduction in computational cost without reducing accuracy. The modeling idea is based on coupling shell elements applied to the PMUT structural layers with 3D-solid elements applied to the piezoelectric layer. A set of eigenfrequency and frequency domain analyses are presented considering a single ROM of a PMUT performing in different ambients and the performing central frequencies are obtained for every considered scenario. A unique arrangement of 228 PMUTs is presented and tested for its ability to transmit and receive acoustic waves. The operating frequency band of the array and the level of interference and cross-talk among different PMUTs in the near field are estimated. Finally, the results from a preliminary experimental test performed to analyze the acoustic abilities of an 8 × 8 array of PMUTs are presented. A corresponding numerical model is created and the obtained results matched the experimental data, leading to a validation of the modeling technique proposed in this work. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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17 pages, 3639 KiB  
Article
Trojan pH-Sensitive Polymer Particles Produced in a Continuous-Flow Capillary Microfluidic Device Using Water-in-Oil-in-Water Double-Emulsion Droplets
by Ane Larrea, Manuel Arruebo, Christophe A. Serra and Victor Sebastián
Micromachines 2022, 13(6), 878; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13060878 - 31 May 2022
Cited by 4 | Viewed by 2229
Abstract
A facile and robust microfluidic method to produce nanoparticle-in-microparticle systems (Trojan systems) is reported as a delivery vector for the oral administration of active pharmaceutical ingredients. The microfluidic system is based on two coaxial capillaries that produce monodisperse water-in-oil-in-water (W/O/W) double emulsions in [...] Read more.
A facile and robust microfluidic method to produce nanoparticle-in-microparticle systems (Trojan systems) is reported as a delivery vector for the oral administration of active pharmaceutical ingredients. The microfluidic system is based on two coaxial capillaries that produce monodisperse water-in-oil-in-water (W/O/W) double emulsions in a highly controlled fashion with precise control over the resulting particle structure, including the core and shell dimensions. The influence of the three phase flow rates, pH and drying process on the formation and overall size is evaluated. These droplets are then used as templates for the production of pH-sensitive Trojan microparticles after solvent evaporation. The shell of Trojan microparticles is made of Eudragit®, a methacrylic acid-ethyl acrylate copolymer that would enable the Trojan microparticle payload to first pass through the stomach without being degraded and then dissolve in the intestinal fluid, releasing the inner payload. The synthesis of the pH-sensitive Trojan microparticles was also compared with a conventional batch production method. The payloads considered in this work were different in nature: (1) fluorescein, to validate the feasibility of the polymeric shell to protect the payload under gastric pH; (2) poly(D,L-lactic acid/glycolic acid)-PLGA nanoparticles loaded with the antibiotic rifampicin. These PLGA nanoparticles were produced also using a microfluidic continuous process and (3) PLGA nanoparticles loaded with Au nanoparticles to trace the PLGA formulation under different environments (gastric and intestinal), and to assess whether active pharmaceutical ingredient (API) encapsulation in PLGA is due efficiently. We further showed that Trojan microparticles released the embedded PLGA nanoparticles in contact with suitable media, as confirmed by electron microscopy. Finally, the results show the possibility of developing Trojan microparticles in a continuous manner with the ability to deliver therapeutic nanoparticles in the gastrointestinal tract. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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15 pages, 3813 KiB  
Article
Numerical Analysis of an Unsteady, Electroviscous, Ternary Hybrid Nanofluid Flow with Chemical Reaction and Activation Energy across Parallel Plates
by Muhammad Bilal, A. El-Sayed Ahmed, Rami Ahmad El-Nabulsi, N. Ameer Ahammad, Khalid Abdulkhaliq M. Alharbi, Mohamed Abdelghany Elkotb, Waranont Anukool and Zedan A. S. A.
Micromachines 2022, 13(6), 874; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13060874 - 31 May 2022
Cited by 34 | Viewed by 2336
Abstract
Despite the recycling challenges in ionic fluids, they have a significant advantage over traditional solvents. Ionic liquids make it easier to separate the end product and recycle old catalysts, particularly when the reaction media is a two-phase system. In the current analysis, the [...] Read more.
Despite the recycling challenges in ionic fluids, they have a significant advantage over traditional solvents. Ionic liquids make it easier to separate the end product and recycle old catalysts, particularly when the reaction media is a two-phase system. In the current analysis, the properties of transient, electroviscous, ternary hybrid nanofluid flow through squeezing parallel infinite plates is reported. The ternary hybrid nanofluid is synthesized by dissolving the titanium dioxide (TiO2), aluminum oxide (Al2O3), and silicon dioxide (SiO2) nanoparticles in the carrier fluid glycol/water. The purpose of the current study is to maximize the energy and mass transfer rate for industrial and engineering applications. The phenomena of fluid flow is studied, with the additional effects of the magnetic field, heat absorption/generation, chemical reaction, and activation energy. The ternary hybrid nanofluid flow is modeled in the form of a system of partial differential equations, which are subsequently simplified to a set of ordinary differential equations through resemblance substitution. The obtained nonlinear set of dimensionless ordinary differential equations is further solved, via the parametric continuation method. For validity purposes, the outcomes are statistically compared to an existing study. The results are physically illustrated through figures and tables. It is noticed that the mass transfer rate accelerates with the rising values of Lewis number, activation energy, and chemical reaction. The velocity and energy transfer rate boost the addition of ternary NPs to the base fluid. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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22 pages, 1778 KiB  
Article
TinyML: Enabling of Inference Deep Learning Models on Ultra-Low-Power IoT Edge Devices for AI Applications
by Norah N. Alajlan and Dina M. Ibrahim
Micromachines 2022, 13(6), 851; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13060851 - 29 May 2022
Cited by 36 | Viewed by 10775
Abstract
Recently, the Internet of Things (IoT) has gained a lot of attention, since IoT devices are placed in various fields. Many of these devices are based on machine learning (ML) models, which render them intelligent and able to make decisions. IoT devices typically [...] Read more.
Recently, the Internet of Things (IoT) has gained a lot of attention, since IoT devices are placed in various fields. Many of these devices are based on machine learning (ML) models, which render them intelligent and able to make decisions. IoT devices typically have limited resources, which restricts the execution of complex ML models such as deep learning (DL) on them. In addition, connecting IoT devices to the cloud to transfer raw data and perform processing causes delayed system responses, exposes private data and increases communication costs. Therefore, to tackle these issues, there is a new technology called Tiny Machine Learning (TinyML), that has paved the way to meet the challenges of IoT devices. This technology allows processing of the data locally on the device without the need to send it to the cloud. In addition, TinyML permits the inference of ML models, concerning DL models on the device as a Microcontroller that has limited resources. The aim of this paper is to provide an overview of the revolution of TinyML and a review of tinyML studies, wherein the main contribution is to provide an analysis of the type of ML models used in tinyML studies; it also presents the details of datasets and the types and characteristics of the devices with an aim to clarify the state of the art and envision development requirements. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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17 pages, 23820 KiB  
Article
Infrared Transmission Characteristics of Phase Transitioning VO2 on Various Substrates
by Samee Azad, Durga Gajula, Nawraj Sapkota, Apparao Rao and Goutam Koley
Micromachines 2022, 13(5), 812; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13050812 - 23 May 2022
Cited by 3 | Viewed by 2163
Abstract
Infrared transmission characteristics of VO2 thin films synthesized on multiple substrates, using a low-pressure direct oxidation technique, have been characterized. Material characterization of these films indicates high material quality, which resulted in large variation of electrical and optical properties at phase transition. [...] Read more.
Infrared transmission characteristics of VO2 thin films synthesized on multiple substrates, using a low-pressure direct oxidation technique, have been characterized. Material characterization of these films indicates high material quality, which resulted in large variation of electrical and optical properties at phase transition. A change in optical transmissivity greater than 80% was observed for these films utilizing infrared (IR) laser illumination at 1550 nm. Phase transition enabled by temperature change induced by a pulsed high-power laser beam resulted in modulated IR laser transmission with a low time constant in VO2 on transparent quartz and muscovite substrates. Investigation of the effect of mechanical strain on phase transition in VO2 grown on flexible muscovite substrate indicate shift in transition temperature to higher for tensile and lower for compressive strains. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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15 pages, 4339 KiB  
Article
Study on Dynamic and Static Performance of a Micro Digital Hydraulic Valve
by Meisheng Yang
Micromachines 2022, 13(5), 741; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13050741 - 07 May 2022
Cited by 2 | Viewed by 1670
Abstract
Previous researchers mostly carried out simulation research and scattered experimental research on the static and dynamic characteristics of the digital valve, but did not form a systematic and in-depth study on the characteristics of the valve. Based on expounding the basic principles and [...] Read more.
Previous researchers mostly carried out simulation research and scattered experimental research on the static and dynamic characteristics of the digital valve, but did not form a systematic and in-depth study on the characteristics of the valve. Based on expounding the basic principles and functions of the valve and the test system, this paper carries out the test research under various variables for three kinds of static characteristics, including pressure differential-flow characteristics, signal-pressure characteristics, and signal-flow characteristics. The optimal control frequency of the valve is obtained from the comprehensive consideration of linear interval, linearity, and hysteresis. Three methods are systematically used to deeply study the dynamic characteristics, and the influencing factors of test results under various test conditions are analyzed. Through the research of this paper, it can provide relevant performance parameters for taking the digital valve as the system control element in the next step, and lay the foundation for the accurate control of the system. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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9 pages, 3307 KiB  
Article
Intravenous Calcium Alginate Microspheres as Drug Delivery Vehicles in Acute Kidney Injury Treatment
by Jia Man, Xiaojie Wang, Jianyong Li, Xiaoyang Cui, Zesheng Hua, Jianfeng Li, Zebing Mao and Shanguo Zhang
Micromachines 2022, 13(4), 538; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13040538 - 29 Mar 2022
Cited by 6 | Viewed by 2231
Abstract
Acute kidney injury (AKI) is a common and severe problem associated with high morbidity, mortality, and healthcare costs. There are no reliable therapeutic interventions except dialysis that could improve survival, limit injury, or speed up recovery. Thus, it is essential to develop new [...] Read more.
Acute kidney injury (AKI) is a common and severe problem associated with high morbidity, mortality, and healthcare costs. There are no reliable therapeutic interventions except dialysis that could improve survival, limit injury, or speed up recovery. Thus, it is essential to develop new therapies to treat AKI. Previous studies revealed that histone deacetylase inhibitor (HDACi) could attenuate renal injury and enhance kidney recovery in AKI. However, the hydrophobic nature of HDACi, such as vorinostat (SAHA), requires organic solvents to promote its dissolution, leading to inevitable detrimental effects. Herein, calcium alginate microspheres (CAM) were prepared by the microfluidic method as HDACi carriers to treat AKI by intravenous injection. First, we designed the structure of the microfluidic channel for the fabrication of the PDMS microfluidic chip in which the emulsion state of droplets was analyzed. As the flow rate increases, the continuous phase changed from laminar flow to the dripping pattern in the microfluidic device. Then, the CAM was fabricated by a W/O microfluidic emulsion template and the size of the microspheres was adjusted from 3 to 7 μm by the concentration of alginate and the flow rate of the continuous phase and dispersal phase. The higher degree of cross-linking of sodium alginate with calcium ions would lead to longer drug release time but lower swelling rates. Furthermore, we selected CAM with suitable sizes as the HDACi carrier and delivered the HDACi-loaded CAM to the AKI mice by intravenous tail injection. The in vivo results showed that the HDACi-loaded CAM could effectively reduce the renal regional inflammatory response and attenuate renal injury. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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15 pages, 2796 KiB  
Article
Miniaturized Wideband Antenna Prototype Operating over the Ku-Band
by Sujan Shrestha, Hijab Zahra, Arslan Kiyani, Mohsen Asadnia, Syed Muzahir Abbas and Abdelhady Mahmoud
Micromachines 2022, 13(3), 471; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13030471 - 19 Mar 2022
Cited by 7 | Viewed by 1784
Abstract
A wideband antenna is proposed based on three-dimensional printing technology. The antenna was designed using the PREPERM 10 material, with permittivity ϵr = 10, where the overall height of the proposed prototype was maintained as 12.83 mm (0.51λ), having a [...] Read more.
A wideband antenna is proposed based on three-dimensional printing technology. The antenna was designed using the PREPERM 10 material, with permittivity ϵr = 10, where the overall height of the proposed prototype was maintained as 12.83 mm (0.51λ), having a lateral dimension of 60 mm × 60 mm, at an operating frequency of 12 GHz (λ = 25 mm). The proposed antenna achieved a wide frequency bandwidth with a voltage standing-wave ratio (VSWR) of less than two, from 10 GHz to 15 GHz in the Ku-band, where the maximum directivity was 20 dBi over a reflection coefficient bandwidth of 50%. It showed a miniaturized non-uniform metasurface of 2.4λ × 2.4λ × 0.51λ that was placed at 16.5 mm (0.66λ) above the ground plane, which was 2.4λ × 2.4λ × 0.04λ in dimension. Thus, the overall height of the proposed antenna system from the feed source was 29.33 mm (1.17λ). The total weight of the system including the designed structures made of PREPERM 10 and ABS with copper-painted prototypes was 96 g and 79 g, respectively. The measured results were consistent with the simulated results, demonstrating the feasibility and effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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10 pages, 3848 KiB  
Article
Beam-Membrane Coupled Piezoelectric Micromachined Ultrasonic Transducers with Enhanced Transmitting Sensitivity
by Mengjiao Qu, Xuying Chen, Ke Zhu, Xishan Guo and Jin Xie
Micromachines 2022, 13(3), 423; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13030423 - 09 Mar 2022
Cited by 4 | Viewed by 2192
Abstract
Piezoelectric micromachined ultrasonic transducers (PMUTs) are a promising alternative to conventional bulk piezoelectric ceramic-based ultrasonic transducers. However, the transmitting sensitivity of the reported PMUTs is far from satisfactory. In this paper, we report a beam-membrane coupled PMUT (BM-PMUT), which enhances the transmitting sensitivity [...] Read more.
Piezoelectric micromachined ultrasonic transducers (PMUTs) are a promising alternative to conventional bulk piezoelectric ceramic-based ultrasonic transducers. However, the transmitting sensitivity of the reported PMUTs is far from satisfactory. In this paper, we report a beam-membrane coupled PMUT (BM-PMUT), which enhances the transmitting sensitivity via simultaneously increasing the acoustic emission areas and maintaining the comparable vibration amplitude. Experimental results show that the center and edge transmitting sensitivities of the BM-PMUT are 108.1 and 96 nm/V at 370 kHz, which are 109.9 and 49.6 nm/V at 677 kHz for the traditional PMUT (T-PMUT). Thus, the BM-PMUT realizes piston-like mode shapes and achieves around twofold improvement in the effective acoustic emission area relative to the traditional T-PMUT of the same size. Due to the larger acoustic emission areas and comparable vibration amplitudes, the normalized far-field sound pressure level of the BM-PMUT is 8.5 dB higher than that of the T-PMUT. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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8 pages, 1282 KiB  
Article
Semi-Automated Microfluidic Device Combined with a MiniPCR-Duplex Lateral Flow Dipstick for Screening and Visual Species Identification of Lymphatic Filariae
by Achinya Phuakrod, Navapon Kusuwan, Witsaroot Sripumkhai, Pattaraluck Pattamang and Sirichit Wongkamchai
Micromachines 2022, 13(2), 336; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13020336 - 21 Feb 2022
Cited by 3 | Viewed by 1883
Abstract
Lymphatic filariasis (LF) is a leading cause of permanent disability worldwide that has been listed as a neglected tropical disease by the World Health Organization. Significant progress made by the Global Program to Eliminate Lymphatic Filariasis (GPELF) has led to a substantial decline [...] Read more.
Lymphatic filariasis (LF) is a leading cause of permanent disability worldwide that has been listed as a neglected tropical disease by the World Health Organization. Significant progress made by the Global Program to Eliminate Lymphatic Filariasis (GPELF) has led to a substantial decline in the population of the worm that causes LF infection. Diagnostic assays capable of detecting low levels of parasite presence are needed to diagnose LF. There is also a need for new tools that can be used in areas where multiple filarial species are coendemic and for mass screening or for use in a point-of-care setting. In the present study, we applied our previously developed semi-automated microfluidic device in combination with our recently developed mini polymerase chain reaction (miniPCR) with a duplex lateral flow dipstick (DLFD) (miniPCR-DLFD) for rapid mass screening and visual species identification of lymphatic filariae in human blood. The study samples comprised 20 Brugia malayi microfilariae (mf) positive human blood samples, 14 Wuchereria bancrofti mf positive human blood samples and 100 mf negative human blood samples. Microfilariae detection and visual species identification was performed using the microfluidic device. To identify the species of the mf trapped in the microfluidic chips, DNA of the trapped mf was extracted for miniPCR amplification of W. bancrofti and B. malayi DNA followed by DLFD. Thick blood smear staining for microfilariae detection was used as the gold standard technique. Microfilariae screening and visual species identification using our microfluidic device plus miniPCR-DLFD platform yielded results concordant with those of the gold standard thick blood smear technique. The microfluidic device, the miniPCR and the DLFD are all portable and do not require additional equipment. Use of this screening and visual species identification platform will facilitate reliable, cost-effective, and rapid surveillance for the presence of LF infection in resource-poor settings. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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13 pages, 10225 KiB  
Article
Single RGB Image 6D Object Grasping System Using Pixel-Wise Voting Network
by Zhongjie Zhang, Chengzhe Zhou, Yasuharu Koike and Jiamao Li
Micromachines 2022, 13(2), 293; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13020293 - 13 Feb 2022
Cited by 5 | Viewed by 1937
Abstract
A robotic system that can autonomously recognize object and grasp it in a real scene with heavy occlusion would be desirable. In this paper, we integrate the techniques of object detection, pose estimation and grasping plan on Kinova Gen3 (KG3), a 7 degrees [...] Read more.
A robotic system that can autonomously recognize object and grasp it in a real scene with heavy occlusion would be desirable. In this paper, we integrate the techniques of object detection, pose estimation and grasping plan on Kinova Gen3 (KG3), a 7 degrees of freedom (DOF) robotic arm with a low-performance native camera sensor, to implement an autonomous real-time 6 dimensional (6D) robotic grasping system. To estimate the object 6D pose, the pixel-wise voting network (PV-net), is applied in the grasping system. However, the PV-net method can not distinguish the object from its photo through only RGB image input. To meet the demands of a real industrial environment, a rapid analytical method on a point cloud is developed to judge whether the detected object is real or not. In addition, our system shows a stable and robust performance in different installation positions with heavily cluttered scenes. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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17 pages, 5352 KiB  
Article
Wafer-Level Filling of MEMS Vapor Cells Based on Chemical Reaction and Evaporation
by Ping Guo, Hongling Meng, Lin Dan and Jianye Zhao
Micromachines 2022, 13(2), 217; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13020217 - 29 Jan 2022
Cited by 5 | Viewed by 2035
Abstract
Micro-electro-mechanical system (MEMS) vapor cells are key components for sensors such as chip-scale atomic clocks (CSACs) and magnetometers (CSAMs). Many approaches have been proposed to fabricate MEMS vapor cells. In this article, we propose a new method to fabricate wafer-level filling of MEMS [...] Read more.
Micro-electro-mechanical system (MEMS) vapor cells are key components for sensors such as chip-scale atomic clocks (CSACs) and magnetometers (CSAMs). Many approaches have been proposed to fabricate MEMS vapor cells. In this article, we propose a new method to fabricate wafer-level filling of MEMS vapor cells based on chemical reaction and evaporation. The Cs metals are firstly obtained through the chemical reaction between cesium chloride and barium azide in a reservoir baseplate. Then, the Cs metals are evaporated to the preform through the microchannel plate and condensed on the inner glass surface of the preform. Lastly, the MEMS vapor cells are filled with buffer gas, sealed by anodic bonding, and mechanically diced into three dimensions: 5 mm × 5 mm × 1.2 mm, 4 mm × 4 mm × 1.2 mm, and 3 mm × 3 mm × 1.2 mm. The full width at half maximum (FWHM) linewidth of the coherent population trapping (CPT) signal of the MEMS vapor cells is found to be 4.33 kHz. The intrinsic linewidth is about 1638 Hz. Based on the CPT signal, the frequency stability is 4.41 × 10−12@1000 s. The results demonstrate that the presented method of the wafer-level filling of MEMS vapor cells fulfills the requirements of sensors such as CSACs. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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10 pages, 3100 KiB  
Article
A Novel Dye-Sensitized Solar Cell Structure Based on Metal Photoanode without FTO/ITO
by Jianjun Yang, Xiaobao Yu, Yaxin Li, Guilin Cheng, Zichuan Yi, Zhi Zhang, Feng Chi and Liming Liu
Micromachines 2022, 13(1), 122; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13010122 - 13 Jan 2022
Cited by 8 | Viewed by 1858
Abstract
Traditional dye-sensitized solar cells (DSSC) use FTO/ITO containing expensive rare elements as electrodes, which are difficult to meet the requirements of flexibility. A new type of flexible DSSC structure with all-metal electrodes without rare elements is proposed in this paper. Firstly, a light-receiving [...] Read more.
Traditional dye-sensitized solar cells (DSSC) use FTO/ITO containing expensive rare elements as electrodes, which are difficult to meet the requirements of flexibility. A new type of flexible DSSC structure with all-metal electrodes without rare elements is proposed in this paper. Firstly, a light-receiving layer was prepared outside the metal photoanode with small holes to realize the continuous oxidation-reduction reaction in the electrolyte; Secondly, the processing technology of the porous titanium dioxide (TiO2) film was analyzed. By testing the J–V characteristics, it was found that the performance is better when the heating rate is slow. Finally, the effects of different electrode material combinations were compared through experiments. Our results imply that in the case of all stainless-steel electrodes, the open-circuit voltage can reach 0.73 V, and in the case of a titanium photoanode, the photoelectric conversion efficiency can reach 3.86%. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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12 pages, 4098 KiB  
Article
A Fast-Response Driving Waveform Design Based on High-Frequency Voltage for Three-Color Electrophoretic Displays
by Hu Zhang, Zichuan Yi, Liming Liu, Feng Chi, Yunfeng Hu, Sida Huang, Yu Miao and Li Wang
Micromachines 2022, 13(1), 59; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13010059 - 30 Dec 2021
Cited by 2 | Viewed by 2095
Abstract
Three-color electrophoretic displays (EPDs) have the characteristics of colorful display, reflection display, low power consumption, and flexible display. However, due to the addition of red particles, response time of three-color EPDs is increased. In this paper, we proposed a new driving waveform based [...] Read more.
Three-color electrophoretic displays (EPDs) have the characteristics of colorful display, reflection display, low power consumption, and flexible display. However, due to the addition of red particles, response time of three-color EPDs is increased. In this paper, we proposed a new driving waveform based on high-frequency voltage optimization and electrophoresis theory, which was used to shorten the response time. The proposed driving waveform was composed of an activation stage, a new red driving stage, and a black or white driving stage. The response time of particles was effectively reduced by removing an erasing stage. In the design process, the velocity of particles in non-polar solvents was analyzed by Newton’s second law and Stokes law. Next, an optimal duration and an optimal frequency of the activation stage were obtained to reduce ghost images and improve particle activity. Then, an optimal voltage which can effectively drive red particles was tested to reduce the response time of red particles. Experimental results showed that compared with a traditional driving waveform, the proposed driving waveform had a better performance. Response times of black particles, white particles and red particles were shortened by 40%, 47.8% and 44.9%, respectively. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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Review

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21 pages, 4643 KiB  
Review
Circuit-Based Design of Microfluidic Drop Networks
by Nassim Rousset, Christian Lohasz, Julia Alicia Boos, Patrick M. Misun, Fernando Cardes and Andreas Hierlemann
Micromachines 2022, 13(7), 1124; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13071124 - 16 Jul 2022
Cited by 4 | Viewed by 2550
Abstract
Microfluidic-drop networks consist of several stable drops—interconnected through microfluidic channels—in which organ models can be cultured long-term. Drop networks feature a versatile configuration and an air–liquid interface (ALI). This ALI provides ample oxygenation, rapid liquid turnover, passive degassing, and liquid-phase stability through capillary [...] Read more.
Microfluidic-drop networks consist of several stable drops—interconnected through microfluidic channels—in which organ models can be cultured long-term. Drop networks feature a versatile configuration and an air–liquid interface (ALI). This ALI provides ample oxygenation, rapid liquid turnover, passive degassing, and liquid-phase stability through capillary pressure. Mathematical modeling, e.g., by using computational fluid dynamics (CFD), is a powerful tool to design drop-based microfluidic devices and to optimize their operation. Although CFD is the most rigorous technique to model flow, it falls short in terms of computational efficiency. Alternatively, the hydraulic–electric analogy is an efficient “first-pass” method to explore the design and operation parameter space of microfluidic-drop networks. However, there are no direct electric analogs to a drop, due to the nonlinear nature of the capillary pressure of the ALI. Here, we present a circuit-based model of hanging- and standing-drop compartments. We show a phase diagram describing the nonlinearity of the capillary pressure of a hanging drop. This diagram explains how to experimentally ensure drop stability. We present a methodology to find flow rates and pressures within drop networks. Finally, we review several applications, where the method, outlined in this paper, was instrumental in optimizing design and operation. Full article
(This article belongs to the Special Issue Micro and Smart Devices and Systems)
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