Microsystem Technologies最新文献

We examined the energy production assessment for heat flow of non-Newtonian ionic liquids within a wavy microchannel, considering the impact of finite ionic size and electroosmotic actuation induced by the applied electric field. A numerical method based on the finite element approach was utilized to determine the associated flow, electrical-double layer potential, and temperature fields. The current model was validated against existing theoretical results. Entropy production, including viscous, thermal, Joule, and total entropy generation within the wavy microchannel, was explored by varying the Brinkman number, thermal Peclet number, steric factor for finite ionic size, Carreau number, and dimensionless amplitude. Increasing the Carreau number resulted in higher shear-thinning behavior of the liquid, leading to higher total entropy generation. Conversely, an increase in finite ionic size reduced entropy generation. Entropy generation decreased with increasing amplitude of the wavy wall. Notably, compared to the plane channel, wavy microchannels consistently exhibited reduced entropy generation. The insights gained from this study are relevant to the development of efficient heat-exchanging devices for electronic cooling.

This article investigates the nonlinear dynamic response of the magneto-electro-thermo-elastic (METE) laminated microbeams in post-buckling state considering the modified couple stress theory. Based on the nonlinear post-buckling dynamic model of the microbeam, considering the main parameter resonance, the model is solved and analyzed to obtain the nonlinear vibration amplitude frequency response relationship by applying the multi-scale method. Then, the Jacobi matrix is used for steady-state analysis of the microbeam. In numerical examples, the effects of material length scale parameter, magneto-electro-thermo field, axial static and dynamic loads, and span-thickness ratio on the dynamic instability region and amplitude frequency response curve of METE laminated microbeams are discussed.

In this article, a novel Complementary Metal Oxide Semiconductor (CMOS) instrumentation amplifier is designed using UMC 90 nm technology with an operating power supply of ± 0.9 V. A differential and operational amplifier with improved gain and low power dissipation were also designed. Because of the ease with which gain may be varied, instrumentation amplifiers have traditionally been preferred. Instead of passive-resistive loads, NMOS is used as active loads (in linear region behaves like a resistor), reducing the die area and lowering power consumption. As a result, active loads produce greater resistance values than passive loads, leading to higher power gains. Previous studies of two-stage Op-Amps have shown that the overall gain is lowered when there is a resistive load at the output. Another issue with a two-stage Op-Amps is the trade-off between speed and gain. An instrumentation amplifier with 97.69 dB differential gain and 135.72 dB common mode rejection ratio (CMRR) has been attained utilising Cadence virtuoso environment UMC 90 nm CMOS process, and the layout area of proposed design with padding is 79.005 μm × 85.17 μm.

This paper investigates the stability issue in direct current microgrid (DC MGs) due to linear and nonlinear constant power load (CPL). The deterioration can be damped out by inserting virtual resistances to minimize the impact of negative resistance of the CPL. However, large virtual resistances caused low stability region. This paper proposed a dual series virtual impedance with fuzzy logic-based voltage and current feed-forward controller. The dual series virtual impedance and fuzzy logic (FL) are used for improvement of transient behavior and steady-state error. However, the crossover frequency increased by inserting CPL is minimized but not much improved by virtual impedance controller. A fuzzy logic-based voltage and current feedforward controller moves from instable to stable region. With FL based current feedforward controller, the crossover frequency has been minimized from 454 rad/sec to 23.8 rad/sec for 5 kW load. The feedforward current can not only improve the transient response but also mitigate the crossover frequency for small-signal modelling stability of microgrids. The comparative stability and transient performance have been demonstrated for variation of CPL (5–9 kW) and source. The hardware prototypes and simulation analysis are used to validate the proposed stable operation criteria of the DC microgrid.

This paper presents a comprehensive analysis of a stand-alone integrated renewable energy system (IRES) for addressing the technical, economic, and operational challenges. In the context, different renewable resource based three configurations viz: SPV/BES, HPP/SPV/BES, and BGG/HPP/SPV/BES are compared in terms of life cycle cost (LCC) and cost of energy (COE) at 0% loss of power supply probability (LPSP). The system is coded in MATLAB© environment for optimal sizing and economic analysis. The findings suggest that the BGG/HPP/SPV/BES configuration provides the most cost-effective results, showcasing a total LCC of $917,000 and COE of 0.22 $/kWh. In response to technical and operational challenges, particularly those related to load frequency control, a MATLAB/Simulink model of optimal configuration is developed. Introducing a fuzzy logic controller tuned proportional integral derivative (FL-PID) controller, aiming to sustain equilibrium in active power, stable DC bus voltage, consistent output AC voltage, effectively managing fluctuations in solar radiation and load demand. These findings provide vital insights for the successful design and implementation of IRESs.

Learning disorders, an umbrella term for a range of learning difficulties, impair a person's capacity to learn new skills. Dysgraphia is one of the prevalent learning disorders among children all over the globe. It is defined as a child's functional restriction in establishing accurate letter or word construction, inadequate speed, and readability of written text. Lack of availability of experts who can diagnose and high diagnostic cost, makes it important to discover a diagnostic approach for dysgraphia that is accurate, accessible and simple to use. Analyzing handwriting is the most common technique to detect dysgraphia which can be automated through image processing techniques. The use of deep learning algorithms has become increasingly widespread in image processing over the course of the last few decades and analysis. However, the effective classification of these handwritten images presents a number of challenges like low accuracy, inadequate availability of labelled data for training purposes. Considering the notable efficacy demonstrated by the Vision Transformer (ViT) in image classification, we proposed a ViT-based classification model in this paper. This model splits handwriting images into patches and then process those through a transformer. Just like word embedding, these input image patches are passed in a sequence to the transformer. To compare performance of proposed model, we also applied transfer learning techniques VGG16, VGG19, ResNet50 and InceptionV3. After comparing the results, it was found that Vision Transformers are best suitable for the classification. Vision transformer has outperformed with macro average F1 score value of 0.92 for the classification. Out of all pretrained models VGG16 performed best with the macro average F1 score value of 0.90. The findings of this study indicate that ViT-based model has the potential to assist experts in the early detection of dysgraphia.

A piezoelectric in-plane resonator with symmetrical oblique-beam amplification mechanism was analyzed and developed. The resonator is comprised of a piezoelectric-heterogeneous-bimorph beam in the middle and elastic oblique beams symmetrically distributed on both sides. Firstly, analytical model for its in-plan deformation was derived by combining elastic deformation of the oblique beams with electrostriction bending of the piezoelectric beam. Then geometric parameters of the whole structure were optimized mainly based on the analytical model to obtain the maximum output horizontal displacement. Besides, its finite element model was simulated and analyzed to verify the analytical model, and find the optimal operating mode, at which the significant amplified horizontal displacement is generated with suppressed vertical one. The resonator was fabricated on a SOI wafer with deposited PNZT piezoelectric film. The fabricated resonator was characterized and tested. Its optimal operating mode was verified and the operating frequency was measured as 16.57 kHz with in-plan displacement of 7.71 μm under 20V_p-p driving signal. The device obtained significant in-plane resonance with almost no out-of-plane displacement.

This article proposes a new process for fabricating a polymer microneedles (MNs) patch integrated with an LED light source (LED-HEMA/MN, LH-MN) using ultraviolet (UV) curing technology. Hydroxyethyl methacrylate (HEMA) is used as the base material, with a focus on studying the active integrated fabrication process of the MNs patch. The study also investigates the morphology, size, mechanical properties, ex vivo skin penetration performance, operating temperature, and performance optimization of the LH-MN. The experimental results show that the LH-MN fabricated using the optimal process has a good appearance, high molding rate, short production cycle, and excellent mechanical properties. It can effectively penetrate the skin without the risk of thermal injury. In addition, the MNs patch (LED-HEMA/HEA-MN, LHH-MN) prepared by optimizing and modifying with hydroxyethyl acrylate (HEA) possesses good flexibility and mechanical properties. It can adapt to different shapes and locations of the affected area, greatly enhancing the practicality of the MNs.