Micromachines

Editorial

3 pages, 168 KiB

Open AccessEditorial

Editorial for a Special Issue of Selected Papers from the 23rd Annual Conference and 12th International Conference of the Chinese Society of Micro-NanoTechnology (CSMNT 2021)

by Qiyuan Feng, Shun Zhang and Qingyou Lu

Micromachines 2023, 14(1), 20; https://doi.org/10.3390/mi14010020 - 21 Dec 2022

Viewed by 1292

Abstract

The Annual Conference and International Conference of the Chinese Association of Micro-NanoTechnology is a comprehensive, cross-disciplinary, high-level academic conference that has been held annually since 1994 and has become an important academic event in the field of micro- and nanotechnology [...] Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

Research

Jump to: Editorial, Review

6 pages, 3096 KiB

Open AccessArticle

A Magnetic Metal Hard Mask on Silicon Substrate for Direct Patterning Ultra-High-Resolution OLED Displays

by Lin Chen, Xiuxia Wang, Yu Wei and Chenggang Zhou

Micromachines 2022, 13(7), 997; https://doi.org/10.3390/mi13070997 - 25 Jun 2022

Cited by 5 | Viewed by 3105

Abstract

With the development of virtual reality/augmented reality (VR/AR) display devices, the conventional fine metal mask is limited by the wet etch process, which no longer meets the demand for high pixels per inch (PPI) displays. We deposited a layer of magnetic metal on [...] Read more.

With the development of virtual reality/augmented reality (VR/AR) display devices, the conventional fine metal mask is limited by the wet etch process, which no longer meets the demand for high pixels per inch (PPI) displays. We deposited a layer of magnetic metal on the silicon substrate by physical vapor deposition (PVD), and then developed a 2-inch, 3175 PPI magnetic metal hard mask on silicon substrate (MMS) through deep silicon etching and other micro-nano processing for patterning Organic Light-Emitting Diodes (OLED) displays, which can achieve smaller pixel size and higher PPI. MMS can not only solve the bottleneck problem of the traditional invar alloy shadow mask with low PPI, but also reduce the bending caused by the deformation of the silicon-based mask due to gravity, so that it achieves high PPI and higher uniformity in OLED displays. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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12 pages, 2546 KiB

Open AccessArticle

Felodipine Determination by a CdTe Quantum Dot-Based Fluorescent Probe

by Yuguang Lv, Yuqing Cheng, Kuilin Lv, Guoliang Zhang and Jiang Wu

Micromachines 2022, 13(5), 788; https://doi.org/10.3390/mi13050788 - 18 May 2022

Cited by 4 | Viewed by 2134

Abstract

In this work, a CdTe quantum dot-based fluorescent probe was synthesized to determine felodipine (FEL). The synthesis conditions, structure, and interaction conditions with FEL of CdTe quantum dots were analysed by fluorescence spectrophotometry, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–visible spectroscopy, [...] Read more.

In this work, a CdTe quantum dot-based fluorescent probe was synthesized to determine felodipine (FEL). The synthesis conditions, structure, and interaction conditions with FEL of CdTe quantum dots were analysed by fluorescence spectrophotometry, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–visible spectroscopy, and TEM. The CdTe QD concentration was 2.0 × 10⁻⁴ mol/L. The amount of quantum dots controlled in the experiment was 0.8 mL. The controlled feeding ratio of N (Cd²⁺):N (Te²⁻):N (TGA) was 2:1:4, the heating temperature was 140 °C, the heating time was 60 min, and the pH of the QD precursor was adjusted to 11 for subsequent experiments. The UV–visible spectrum showed that the emission wavelength of CdTe quantum dots at 545 nm was the strongest and symmetric. The particle size of the synthesized quantum dots was approximately 5 nm. In the interaction of CdTe quantum dots with FEL, the FEL dosage was 1.0 mL, the optimal pH value of Tris-HCl buffer was 8.2, the amount of buffer was 1.5 mL, and the reaction time was 20 min. The standard curve of FEL was determined under the optimal synthesis conditions of CdTe quantum dots and reaction of CdTe quantum dots with FEL. The linear equation was Y = 3.9448x + 50.068, the correlation coefficient R2 was 0.9986, and the linear range was 5 × 10⁻⁶–1.1 × 10⁻⁴ mol/L. A CdTe quantum dot-based fluorescent probe was successfully constructed and could be used to determine the FEL tablet content. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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11 pages, 4800 KiB

Open AccessArticle

Design and Development of a 2 × 2 Array Piezoelectric–Electromagnetic Hybrid Energy Harvester

by Bing Han, Shubin Zhang, Jianbin Liu and Yanfeng Jiang

Micromachines 2022, 13(5), 752; https://doi.org/10.3390/mi13050752 - 10 May 2022

Cited by 2 | Viewed by 3277

Abstract

Energy harvesting technology is regarded as a feasible solution for the continuous power supply of microelectronic devices. Efforts have been made to improve the output power of all kinds of energy harvesting devices. This paper reports a 2 × 2 array piezoelectric–electromagnetic hybrid [...] Read more.

Energy harvesting technology is regarded as a feasible solution for the continuous power supply of microelectronic devices. Efforts have been made to improve the output power of all kinds of energy harvesting devices. This paper reports a 2 × 2 array piezoelectric–electromagnetic hybrid energy harvester that achieves high power output through the combination of piezoelectric and electromagnetic conversion. The harvester included four piezoelectric–electromagnetic hybrid modules, each of which consisted of a piezoelectric sheet, a permanent magnet and a wound coil. The permanent magnet, also serving as the mass block of the cantilever beam when subjected to external stimulus, contributed to a large displacement of the vibration and generated high output power. At an acceleration of 1 g and a resonance frequency of 70.4 Hz, the measured maximum output power of the hybrid energy harvester was 66.08 mW, of which the piezoelectric and electromagnetic portions were 56.96 and 9.12 mW, respectively. Furthermore, in a charging experiment, a capacitor of 23.5 mF was charged to 11.5 V within 20 s, which demonstrates a practical application of the hybrid energy harvester for microelectronic devices. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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15 pages, 5207 KiB

Open AccessArticle

Design, Fabrication, and Characterization of a Laser-Controlled Explosion-Initiating Device with Integrated Safe-and-Arm, EMP-Resistant, and Fast-Acting Technology Based on Photovoltaic Power Converter

by Guofu Yin, Huiqin Bao, Yulong Zhao, Wei Ren, Xiangfei Ji, Jianhua Cheng and Xi Ren

Micromachines 2022, 13(5), 728; https://doi.org/10.3390/mi13050728 - 30 Apr 2022

Cited by 1 | Viewed by 2006

Abstract

To augment the intelligence and safety of a rocket or ammunition engine start, an intelligent initiation system needs to be included in the data link. A laser-controlled intelligent initiation system with inherent safety and a laser-controlled explosion-initiating device (LCEID) incorporating electromagnetic pulse (EMP) [...] Read more.

To augment the intelligence and safety of a rocket or ammunition engine start, an intelligent initiation system needs to be included in the data link. A laser-controlled intelligent initiation system with inherent safety and a laser-controlled explosion-initiating device (LCEID) incorporating electromagnetic pulse (EMP) resistant, safe-and-arms fast-acting modular device based on photovoltaic power converter technology is designed and fabricated in this work. LCEID is an integrated multi-function module consisting of the optical beam expander, GaAs photovoltaic (PV) array, safe-and-arms integrated circuit, and low-energy initiator. These components contribute to EMP resistance, fast-acting, safe-and-arm, and reliable firing, respectively. To achieve intelligent initiation, each LCEID has a unique “identification information” and a “broadcast address” embedded in integrated-circuit read-only memory (ROM), which is controlled by encoded laser addressing. The GaAs PV array was investigated to meet the low-energy initiator firing voltage requirements. Experimental results show that the open-circuit voltage, short-circuit current, and maximum power output of the four-junction GaAs PV array illuminated by a 5.5 W/cm² laser beam were 220 mA, 21.5 V, and 3.70 W, respectively. When the voltage of the 22 μF energy storage capacitor exceeds 20 V, the laser charging time is found to be shorter than 2.5 s. Other aspects of LCEID, such as laser energy coupling efficiency, the firing process, and the energy-boosting mechanism, were explored. Measurements show that the coupling efficiency of the micro lens with a radius of curvature D = 20 μm and size of r = 50 μm reaches a maximum of 93.5%. Furthermore, for more than 18 V charge voltage, the LCEID is found to perform reliably. The fabricated LCEID demonstrated a high level of integration and intrinsic safety, as well as a finely tailored initiation performance that could be useful in military applications. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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15 pages, 4404 KiB

Open AccessArticle

Heat Dissipation Characteristics of IGBT Module Based on Flow-Solid Coupling

by Lipeng Tan, Peisheng Liu, Chenhui She, Pengpeng Xu, Lei Yan and Hui Quan

Micromachines 2022, 13(4), 554; https://doi.org/10.3390/mi13040554 - 31 Mar 2022

Cited by 19 | Viewed by 3571

Abstract

With the increase of power level and integration in electric vehicle controllers, the heat flux of the key silicon-based IGBT (Insulated Gate Bipolar Transistor) device has reached its physical limit. At present, third-generation semiconductor devices including SiC MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor) are gradually [...] Read more.

With the increase of power level and integration in electric vehicle controllers, the heat flux of the key silicon-based IGBT (Insulated Gate Bipolar Transistor) device has reached its physical limit. At present, third-generation semiconductor devices including SiC MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor) are gradually replacing the dominant IGBT module. The hybrid IGBT module consists of both and can improve the performance and reduce the cost of controllers. Limits due to the installation space, location, and other conditions in the car make it difficult to meet the requirements of controllers with an air-cooled heatsink due to their large size and limited heat dissipation capacity. A smaller and more powerful water-cooled heatsink case is required to ensure the heat dissipation of the IGBT in the controller. Based on previous experience in finite element numerical simulation, hydrodynamics calculation, and heat transfer calculation, ANSYS Workbench finite element software was used to analyze the thermal resistance of each structure inside the module and the heatsink structure. The fluid characteristics and heat transfer performance of three different flow channel structures were analyzed, and the design of the cooling flow fin was improved to provide a reference for the heat dissipation of the hybrid IGBT module. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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13 pages, 3305 KiB

Open AccessArticle

Radio Frequency Resonator-Based Flexible Wireless Pressure Sensor with MWCNT-PDMS Bilayer Microstructure

by Baochun Xu, Mingyue Li, Min Li, Haoyu Fang, Yu Wang, Xun Sun, Qiuquan Guo, Zhuopeng Wang, Yijian Liu and Da Chen

Micromachines 2022, 13(3), 404; https://doi.org/10.3390/mi13030404 - 1 Mar 2022

Cited by 11 | Viewed by 3541

Abstract

Flexible pressure sensors have been widely applied in wearable devices, e-skin, and the new generation of robots. However, most of the current sensors use connecting wires for energy supply and signal transmission, which presents an obstacle for application scenarios requiring long endurance and [...] Read more.

Flexible pressure sensors have been widely applied in wearable devices, e-skin, and the new generation of robots. However, most of the current sensors use connecting wires for energy supply and signal transmission, which presents an obstacle for application scenarios requiring long endurance and large movement, especially. Flexible sensors combined with wireless technology is a promising research field for realizing efficient state sensing in an active state. Here, we designed and fabricated a soft wireless passive pressure sensor, with a fully flexible Ecoflex substrate and a multi-walled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) bilayer pyramid dielectric structure. Based on the principle of the radio-frequency resonator, the device achieved pressure sensing with a changeable capacitance. Subsequently, the effect of the pyramid density was simulated by the finite element method to improve the sensitivity. With one-step embossing and spin-coating methods, the fabricated sensor had an optimized sensitivity of 14.25 MHz/kPa in the low-pressure range. The sensor exhibited the potential for application in limb bending monitoring, thus demonstrating its value for long-term wireless clinical monitoring. Moreover, the radio frequency coupling field can be affected by approaching objects, which provides a possible route for realizing non-contact sensing in applications such as pre-collision warning. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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10 pages, 2439 KiB

Open AccessArticle

High-Resolution Separation of Nanoparticles Using a Negative Magnetophoretic Microfluidic System

by Lin Zeng, Xi Chen, Rongrong Zhang, Shi Hu, Hongpeng Zhang, Yi Zhang and Hui Yang

Micromachines 2022, 13(3), 377; https://doi.org/10.3390/mi13030377 - 26 Feb 2022

Cited by 11 | Viewed by 2465

Abstract

The separation and purification of a sample of interest is essential for subsequent detection and analysis procedures, but there is a lack of effective separation methods with which to purify nano-sized particles from the sample media. In this paper, a microfluidic system based [...] Read more.

The separation and purification of a sample of interest is essential for subsequent detection and analysis procedures, but there is a lack of effective separation methods with which to purify nano-sized particles from the sample media. In this paper, a microfluidic system based on negative magnetophoresis is presented for the high-resolution separation of nanoparticles. The system includes on-chip magnetic pole arrays and permalloys that symmetrically distribute on both sides of the separation channel and four permanent magnets that provide strong magnetic fields. The microfluidic system can separate 200 nm particles with a high purity from the mixture (1000 nm and 200 nm particles) due to a magnetic field gradient as high as 10,000 T/m being generated inside the separation channel, which can provide a negative magnetophoretic force of up to 10 pN to the 1000 nm particle. The overall recovery rate of the particles reaches 99%, the recovery rate of 200 nm particles is 84.2%, and the purity reaches 98.2%. Compared with the existing negative magnetophoretic separation methods, our system not only exhibits high resolution on particle sizes (800 nm), but also improves the sample processing throughput, which reaches 2.5 μL/min. The microfluidic system is expected to provide a new solution for the high-purity separation of nanoparticles, as well as nanobiological samples. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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13 pages, 3237 KiB

Open AccessArticle

Oocyte Penetration Speed Optimization Based on Intracellular Strain

by Yaowei Liu, Maosheng Cui, Yidi Zhang, Xiangfei Zhao, Mingzhu Sun and Xin Zhao

Micromachines 2022, 13(2), 309; https://doi.org/10.3390/mi13020309 - 17 Feb 2022

Cited by 3 | Viewed by 2512

Abstract

Oocyte penetration is an essential step for many biological technologies, such as animal cloning, embryo microinjection, and intracytoplasmic sperm injection (ICSI). Although the success rate of robotic cell penetration is very high now, the development potential of oocytes after penetration has not been [...] Read more.

Oocyte penetration is an essential step for many biological technologies, such as animal cloning, embryo microinjection, and intracytoplasmic sperm injection (ICSI). Although the success rate of robotic cell penetration is very high now, the development potential of oocytes after penetration has not been significantly improved compared with manual operation. In this paper, we optimized the oocyte penetration speed based on the intracellular strain. We firstly analyzed the intracellular strain at different penetration speeds and performed the penetration experiments on porcine oocytes. Secondly, we studied the cell development potential after penetration at different penetration speeds. The statistical results showed that the percentage of large intracellular strain decreased by 80% and the maximum and average intracellular strain decreased by 25–38% at the penetration speed of 50 μm/s compared to at 10 μm/s. Experiment results showed that the cleavage rates of the oocytes after penetration increased from 65.56% to 86.36%, as the penetration speed increased from 10 to 50 μm/s. Finally, we verified the gene expression of oocytes after penetration at different speeds. The experimental results showed that the totipotency and antiapoptotic genes of oocytes were significantly higher after penetration at the speed of 50 μm/s, which verified the effectiveness of the optimization method at the gene level. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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7 pages, 1802 KiB

Open AccessArticle

A Thermoelectric MEMS Microwave Power Sensor with Inline Self-Detection Function

by Jiaqi Liu, Yang Hong, Jutao Wang, Chunhua Cai and Zhiqiang Zhang

Micromachines 2022, 13(2), 239; https://doi.org/10.3390/mi13020239 - 31 Jan 2022

Cited by 7 | Viewed by 2610

Abstract

In this paper, the design, fabrication and measurement of a thermoelectric MEMS microwave power sensor with the terminal load inline self-detection function is proposed. The structure of the sensor mainly includes a coplanar waveguide, a thermopile, two terminal load resistors and two calibration [...] Read more.

In this paper, the design, fabrication and measurement of a thermoelectric MEMS microwave power sensor with the terminal load inline self-detection function is proposed. The structure of the sensor mainly includes a coplanar waveguide, a thermopile, two terminal load resistors and two calibration resistors. In order to realize the inline self-detection function, the load and calibration resistors are designed to form a voltage divider circuit. The fabrication of this sensor is compatible with the GaAs MMIC technology. The on-chip performance is tested by using a microwave experimental platform. The measured reflection loss is less than −10 dB at 0.1–10 GHz. When the bias voltage is not applied, the sensitivity of the sensor is 47.39 μV/mW@5 GHz and 32.58 μV/mW@10 GHz, respectively, and when the bias voltage is applied, the sensitivity is 47.50 μV/mW@5 GHz and 32.73 μV/mW@10 GHz, respectively. The difference between the two cases is less than 0.5% at the same frequency, which indicates that whether or not to apply the bias voltage has little effect on the sensitivity. In addition, when the calibration resistance is increased from 50 to 100 Ω, the current flowing through the load resistance is decreased under the same bias voltage. Therefore, the DC power consumed on the load resistance will be significantly reduced. This makes the measured and theoretical results show better agreement, thus verifying the validity of the design. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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12 pages, 1861 KiB

Open AccessArticle

Research on Heat Dissipation of Multi-Chip LED Filament Package

by Lipeng Tan, Peisheng Liu, Chenhui She, Pengpeng Xu, Lei Yan and Hui Quan

Micromachines 2022, 13(1), 77; https://doi.org/10.3390/mi13010077 - 31 Dec 2021

Cited by 8 | Viewed by 2188

Abstract

By studying the substrate material, structure, chip distribution, and array form of the multi-chip light-emitting diode (LED) package, the heat-dissipation capacity of the LED package is improved. Finite element analysis and steady-state thermal analysis are used to simulate and analyze LED packages with [...] Read more.

By studying the substrate material, structure, chip distribution, and array form of the multi-chip light-emitting diode (LED) package, the heat-dissipation capacity of the LED package is improved. Finite element analysis and steady-state thermal analysis are used to simulate and analyze LED packages with different materials and structures. Using the theory of LED illuminance and uniformity, the illuminance of some structures is computed. The results show that the change of substrate material and structure can greatly impact heat dissipation, while changing array forms has little effect on heat dissipation. By improving the spatial distribution of the chip, the temperature superposition problem of the substrate is solved, and the illuminance and uniformity are improved while dissipating heat. The LED filaments of the combined, equidistant, chip-distribution mode have improved heat dissipation. The S-type equal difference has the highest illumination and high illumination uniformity. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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11 pages, 1745 KiB

Open AccessArticle

Calibration Method of Accelerometer Based on Rotation Principle Using Double Turntable Centrifuge

by Xianshan Dong, Xinlong Huang, Guizhen Du, Qinwen Huang, Yixiong Huang, Yun Huang and Ping Lai

Micromachines 2022, 13(1), 62; https://doi.org/10.3390/mi13010062 - 30 Dec 2021

Cited by 9 | Viewed by 2297

Abstract

For linear accelerometers, calibration with a precision centrifuge is a key technology, and the input acceleration imposed on the accelerometer should be accurately obtained in the calibration. However, there are often errors in the installation of sample that make the calibration inaccurate. To [...] Read more.

For linear accelerometers, calibration with a precision centrifuge is a key technology, and the input acceleration imposed on the accelerometer should be accurately obtained in the calibration. However, there are often errors in the installation of sample that make the calibration inaccurate. To solve installation errors and obtain the input acceleration in the calibration of the accelerometer, a calibration method based on the rotation principle using a double turntable centrifuge is proposed in this work. The key operation is that the sub-turntable is rotated to make the input axis of the accelerometer perpendicular to the direction of the centripetal acceleration vector. Models of installation errors of angle and radius were built. Based on these models, the static radius and input acceleration can be obtained accurately, and the calibration of the scale factor, nonlinearity and asymmetry can be implemented. Using this method, measurements of the MEMS accelerometer with a range of ±30 g were carried out. The results show that the discrepancy of performance obtained from different installation positions was smaller than 100 ppm after calibrating the input acceleration. Moreover, the results using this method were consistent with those using the back-calculation method. These results demonstrate that the effectiveness of our proposed method was confirmed. This method can measure the static radius directly eliminating the installation errors of angle and radius, and it simplifies the accelerometer calibration procedure. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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14 pages, 3735 KiB

Open AccessArticle

Rate-Dependent Modeling of Piezoelectric Actuators for Nano Manipulation Based on Fractional Hammerstein Model

by Liu Yang, Zhongyang Zhao, Yi Zhang and Dongjie Li

Micromachines 2022, 13(1), 42; https://doi.org/10.3390/mi13010042 - 28 Dec 2021

Cited by 19 | Viewed by 1951

Abstract

Piezoelectric actuators (PEAs), as a smart material with excellent characteristics, are increasingly used in high-precision and high-speed nano-positioning systems. Different from the usual positioning control or fixed frequency tracking control, the more accurate rate-dependent PEA nonlinear model is needed in random signal dynamic [...] Read more.

Piezoelectric actuators (PEAs), as a smart material with excellent characteristics, are increasingly used in high-precision and high-speed nano-positioning systems. Different from the usual positioning control or fixed frequency tracking control, the more accurate rate-dependent PEA nonlinear model is needed in random signal dynamic tracking control systems such as active vibration control. In response to this problem, this paper proposes a Hammerstein model based on fractional order rate correlation. The improved Bouc-Wen model is used to describe the asymmetric hysteresis characteristics of PEA, and the fractional order model is used to describe the dynamic characteristics of PEA. The nonlinear rate-dependent hysteresis model can be used to accurately describe the dynamic characteristics of PEA. Compared with the integer order model or linear autoregressive model to describe the dynamic characteristics of the PEA Hammerstein model, the modeling accuracy is higher. Moreover, an artificial bee colony algorithm (DE-ABC) based on differential evolution was proposed to identify model parameters. By adding the mutation strategy and chaos search of the genetic algorithm into the previous ABC, the convergence speed of the algorithm is faster and the identification accuracy is higher, and the simultaneous identification of order and coefficient of the fractional model is realized. Finally, by comparing the simulation and experimental data of multiple sets of sinusoidal excitation with different frequencies, the effectiveness of the proposed modeling method and the accuracy and rapidity of the identification algorithm are verified. The results show that, in the wide frequency range of 1–100 Hz, the proposed method can obtain more accurate rate-correlation models than the Bouc-Wen model, the Hammerstein model based on integer order or the linear autoregressive model to describe dynamic characteristics. The maximum error (Max error) is 0.0915 μm, and the maximum mean square error (RMSE) is 0.0244. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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10 pages, 3481 KiB

Open AccessArticle

Study of Microscale Meniscus Confined Electrodeposition Based on COMSOL

by Fuyue Zhang, Dongjie Li, Weibin Rong, Liu Yang and Yu Zhang

Micromachines 2021, 12(12), 1591; https://doi.org/10.3390/mi12121591 - 20 Dec 2021

Cited by 11 | Viewed by 3738

Abstract

The rate and quality of microscale meniscus confined electrodeposition represent the key to micromanipulation based on electrochemistry and are extremely susceptible to the ambient relative humidity, electrolyte concentration, and applied voltage. To solve this problem, based on a neural network and genetic algorithm [...] Read more.

The rate and quality of microscale meniscus confined electrodeposition represent the key to micromanipulation based on electrochemistry and are extremely susceptible to the ambient relative humidity, electrolyte concentration, and applied voltage. To solve this problem, based on a neural network and genetic algorithm approach, this paper optimizes the process parameters of the microscale meniscus confined electrodeposition to achieve high-efficiency and -quality deposition. First, with the COMSOL Multiphysics, the influence factors of electrodeposition were analyzed and the range of high efficiency and quality electrodeposition parameters were discovered. Second, based on the back propagation (BP) neural network, the relationships between influence factors and the rate of microscale meniscus confined electrodeposition were established. Then, in order to achieve effective electrodeposition, the determined electrodeposition rate of 5 × 10⁻⁸ m/s was set as the target value, and the genetic algorithm was used to optimize each parameter. Finally, based on the optimization parameters obtained, we proceeded with simulations and experiments. The results indicate that the deposition rate maximum error is only 2.0% in experiments. The feasibility and accuracy of the method proposed in this paper were verified. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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13 pages, 4643 KiB

Open AccessArticle

A Combined Positioning Method Used for Identification of Concrete Cracks

by Jianzhi Li, Bohao Shen and Junjie Wang

Micromachines 2021, 12(12), 1479; https://doi.org/10.3390/mi12121479 - 29 Nov 2021

Cited by 1 | Viewed by 1656

Abstract

Fully distributed fiber optic sensors are characteristically used for the measurement of long distances and continuous distribution of space. However, due to the different fiber type, fiber length, ambient temperature and strain, fully distributed fiber optic sensors fail to locate damage accurately and [...] Read more.

Fully distributed fiber optic sensors are characteristically used for the measurement of long distances and continuous distribution of space. However, due to the different fiber type, fiber length, ambient temperature and strain, fully distributed fiber optic sensors fail to locate damage accurately and cause a greater error. Therefore, this paper proposes a new positioning method of combining fully distributed fiber optic sensors with fiber Bragg gratings, which enables accurately the localization of a structural damage during the long-term monitoring of fully distributed fiber optic sensors. Moreover, the coupling mechanism of the reflected light from fiber grating and excited Brillouin scattering light is illustrated. Further, it is experimentally verified by locating the cracks of 2 m long reinforced concrete beams. The experimental results show that this proposed method is capable of monitoring the generation of the beam crack and further locating the crack on the concrete beam with an approximate error of 10 cm. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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11 pages, 5378 KiB

Open AccessArticle

A Spiral Distributed Monitoring Method for Steel Rebar Corrosion

by Jianzhi Li, Yiyao Zhao and Junjie Wang

Micromachines 2021, 12(12), 1451; https://doi.org/10.3390/mi12121451 - 26 Nov 2021

Cited by 5 | Viewed by 1714

Abstract

This paper proposes a novel spiral-wound, optic-fiber sensor to monitor the corrosion of steel bars. At the same time, the winding parameters, such as winding angle and pitch, were first theoretically deduced. Then, to decrease light loss, a practically distributed sensor wound onto [...] Read more.

This paper proposes a novel spiral-wound, optic-fiber sensor to monitor the corrosion of steel bars. At the same time, the winding parameters, such as winding angle and pitch, were first theoretically deduced. Then, to decrease light loss, a practically distributed sensor wound onto the protective mortar layer was developed by increasing the winding curvature radius. The spiral distributed sensors were experimentally verified for their feasibility. Experimental results showed that the spiral fiber strain depended on the thickness of the protective mortar layer. Furthermore, the spiral distributed strain well reflected the cracking process of concrete. In addition, the concrete cracking time depended on the thickness of the protective concrete layer. Accordingly, this method is feasible for evaluating the initial and final cracking behaviors of concrete structures and provides a sight for steel bar corrosion. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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Review

Jump to: Editorial, Research

15 pages, 2354 KiB

Open AccessReview

Development of LED Package Heat Dissipation Research

by Peisheng Liu, Chenhui She, Lipeng Tan, Pengpeng Xu and Lei Yan

Micromachines 2022, 13(2), 229; https://doi.org/10.3390/mi13020229 - 30 Jan 2022

Cited by 20 | Viewed by 5020

Abstract

LEDs are widely used in medicine, navigation and landscape lighting. The development of high-power LED is a severe challenge to LED heat dissipation. In this review, packaging technology and packaging structure are reviewed in terms of the thermal performance of LED packaging, and [...] Read more.

LEDs are widely used in medicine, navigation and landscape lighting. The development of high-power LED is a severe challenge to LED heat dissipation. In this review, packaging technology and packaging structure are reviewed in terms of the thermal performance of LED packaging, and related technologies that promote heat dissipation in LED packaging are introduced. The design of three components to enhance heat dissipation in LED packaging is described: substrate, lens and phosphor layer. By conducting a summary of the technology and structure of the package, the defects of LED package technology and structure are deeply investigated, and the package is prospected. This has reference value for the heat dissipation design of the LED package and helps to improve the design and manufacture of the LED package. Full article

(This article belongs to the Special Issue Selected Papers from the 23rd Annual Conference and 12th International Conference of Chinese Society of Micro-Nano Technology (CSMNT 2021))

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