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Hydrodynamic function and spring constant calibration of FluidFM micropipette cantilevers

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Microsystems & Nanoengineering 2024年第1期10卷 277-286页

作者： Attila Bonyár Ágoston G.Nagy Hans Gunstheimer Gotthold Fläschner Robert Horvath Department of Electronics Technology Faculty of Electrical Engineering and InformaticsBudapest University of Technology and EconomicsBudapestHungary Nanobiosensorics Laboratory Institute of Technical Physics and Materials ScienceCentre for Energy ResearchHUN-RENBudapestHungary Nanosurf AG Gräubernstrasse 12CH-4410 LiestalSwitzerland

Fluidic force microscopy(FluidFM)fuses the force sensitivity of atomic force microscopy with the manipulation capabilities of microfluidics by using microfabricated cantilevers with embedded fluidic channels.This innovation initiated new research and development directions in biology,biophysics,and material science.To acquire reliable and reproducible data,the calibration of the force sensor is crucial.Importantly,the hollow FluidFM cantilevers contain a row of parallel pillars inside a rectangular beam.The precise spring constant calibration of the internally structured cantilever is far from trivial,and existing methods generally assume simplifications that are not applicable to these special types of cantilevers.In addition,the Sader method,which is currently implemented by the FluidFM community,relies on the precise measurement of the quality factor,which renders the calibration of the spring constant sensitive to noise.In this study,the hydrodynamic function of these special types of hollow cantilevers was experimentally determined with different instruments.Based on the hydrodynamic function,a novel spring constant calibration method was adapted,which relied only on the two resonance frequencies of the cantilever,measured in air and in a liquid.Based on these results,our proposed method can be successfully used for the reliable,noise-free calibration of hollow FluidFM cantilevers.

关键词： spring cantilever function

A Comprehensive Review on Charging Topologies and Power Electronic Converter Solutions for Electric Vehicles

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 675-694页

作者： Abdelfatah Ali Hossam H.H.Mousa Mostafa F.Shaaban Maher A.Azzouz Ahmed S.A.Awad the Department of electrical engineering American University of Sharjah the Department of electrical engineering South Valley University the Department of electrical and Computer engineering University of Windsor electrical engineering Department Qatar University the Department of electrical and Computer engineering Sultan Qaboos University

Electric vehicles(EVs) are becoming more popular worldwide due to environmental concerns, fuel security, and price volatility. The performance of EVs relies on the energy stored in their batteries, which can be charged using either AC(slow) or DC(fast) chargers. Additionally, EVs can also be used as mobile power storage devices using vehicle-to-grid(V2G) technology. Power electronic converters(PECs) have a constructive role in EV applications, both in charging EVs and in V2G. Hence, this paper comprehensively investigates the state of the art of EV charging topologies and PEC solutions for EV applications. It examines PECs from the point of view of their classifications, configurations, control approaches, and future research prospects and their impacts on power quality. These can be classified into various topologies: DC-DC converters, AC-DC converters, DC-AC converters, and AC-AC converters. To address the limitations of traditional DC-DC converters such as switching losses, size, and high-electromagnetic interference(EMI), resonant converters and multiport converters are being used in high-voltage EV applications. Additionally, power-train converters have been modified for high-efficiency and reliability in EV applications. This paper offers an overview of charging topologies, PECs, challenges with solutions, and future trends in the field of the EV charging station applications.

关键词： Topology DC-DC power converters Vehicle-to-grid Electric vehicle charging Batteries Transportation Electromagnetic interference

Laser‑Induced and MOF‑Derived Metal Oxide/Carbon Composite for Synergistically Improved Ethanol Sensing at Room temperature

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Nano-Micro Letters 2024年第6期16卷 210-220页

作者： Hyeongtae Lim Hyeokjin Kwon Hongki Kang Jae Eun Jang Hyuk‑Jun Kwon Department of electrical engineering and Computer Science DGISTDaegu 42988South Korea Convergence Research Advanced centre for Olfaction DGISTDaegu 42988South Korea

Advancements in sensor technology have significantly enhanced atmospheric monitoring.Notably,metal oxide and carbon(MO_(x)/C)hybrids have gained attention for their exceptional sensitivity and room-temperature sensing performance.However,previous methods of synthesizing MO_(x)/C composites suffer from problems,including inhomogeneity,aggregation,and challenges in micropatterning.Herein,we introduce a refined method that employs a metal–organic framework(MOF)as a precursor combined with direct laser writing.The inherent structure of MOFs ensures a uniform distribution of metal ions and organic linkers,yielding homogeneous MO_(x)/C structures.The laser processing facilitates precise micropatterning(<2μm,comparable to typical photolithography)of the MO_(x)/C crystals.The optimized MOF-derived MO_(x)/C sensor rapidly detected ethanol gas even at room temperature(105 and 18 s for response and recovery,respectively),with a broad range of sensing performance from 170 to 3,400 ppm and a high response value of up to 3,500%.Additionally,this sensor exhibited enhanced stability and thermal resilience compared to previous MOF-based counterparts.This research opens up promising avenues for practical applications in MOF-derived sensing devices.

关键词： Metal-organic frameworks Metal oxide Carbon composite Laser Gas sensor

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Finite-time composite learning control for nonlinear teleoperation systems under networked time-varying delays

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Science China(Information Sciences) 2024年第6期67卷 279-296页

作者： Yana YANG Huixin JIANG Changchun HUA Junpeng LI Institute of electrical engineering Yanshan University

The robust finite-time synchronization control problem is investigated for master-slave networked nonlinear telerobotics systems(NNTSs) in this article. Although there have been some research achievements on finite-time control for the NNTSs, these studies are based on the strong assumptions of communication time delays or can only achieve finite-time bounded convergence even when the external forces are zero.Accordingly and in view of the importance of these issues, a novel robust composite learning adaptive control scheme rendering the finite-time master-slave synchronization is proposed in this paper. In particular, the influence of time delays on finite-time convergence of the system is analyzed by employing the multi-dimension finite-time small-gain framework. Meanwhile, in order to achieve accurate and fast estimation of uncertain parameters of the system, both the online historical and the instantaneous data of the estimation data are explored to derive the new parameter adaptive law under a more realizable interval-excitation(IE) condition.Therefore, the convergence of the position/force synchronization errors and the adaptive parameter estimation errors is obtained in finite time, and enhanced robustness of the closed-loop system will also be ensured.Finally, the superior performance of the proposed control algorithms is validated by numerical simulations and hardware experiments.

关键词： networked teleoperation systems finite-time control exact parameter estimation small-gain theorem unknown communication delays

Real-time Operation Optimization in Active Distribution Networks Based on Multi-agent Deep Reinforcement Learning

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 886-899页

作者： Jie Xu Hongjun Gao Renjun Wang Junyong Liu the College of electrical engineering Sichuan University

The increasing integration of intermittent renewable energy sources(RESs) poses great challenges to active distribution networks(ADNs), such as frequent voltage fluctuations. This paper proposes a novel ADN strategy based on multiagent deep reinforcement learning(MADRL), which harnesses the regulating function of switch state transitions for the realtime voltage regulation and loss minimization. After deploying the calculated optimal switch topologies, the distribution network operator will dynamically adjust the distributed energy resources(DERs) to enhance the operation performance of ADNs based on the policies trained by the MADRL algorithm. Owing to the model-free characteristics and the generalization of deep reinforcement learning, the proposed strategy can still achieve optimization objectives even when applied to similar but unseen environments. Additionally, integrating parameter sharing(PS) and prioritized experience replay(PER) mechanisms substantially improves the strategic performance and scalability. This framework has been tested on modified IEEE 33-bus, IEEE 118-bus, and three-phase unbalanced 123-bus systems. The results demonstrate the significant real-time regulation capabilities of the proposed strategy.

关键词： Real-time systems Switches Scalability Reinforcement learning Deep learning Topology Mathematical models

Inverse design of highly efficient and broadband mode splitter on SOI platform

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Chinese Optics Letters 2024年第1期22卷 59-64页

作者：廖俊鹏田野杨子荣徐豪达唐晨王钰恒张晓伟康哲 Department of electrical engineering and Computer Science Ningbo UniversityNingbo 315211China centre for Optical and Electromagnetic Research College of Optical Science and EngineeringZhejiang UniversityHangzhou 310058China

Mode splitters that directly separate modes without changing their orders are highly promising to improve the flexibility of the mode-division multiplexing systems.In this paper,we design a high-performance mode splitter on the silicon-oninsulator platform with a compact footprint of 14μm×2.5μm using an inverse design method based on shape optimization.The fabrication of this mode splitter requires only a single lithography step and exhibits good fabrication tolerances.The experimental results show that the proposed device exhibits state-of-the-art insertion loss(<0.9 dB)and cross talk(<-16 dB)over a broad bandwidth(1500-1600 nm).Furthermore,the shape optimization method used is implemented to design a dual-mode(de)multiplexer,and the experimental results fulfill the design objective,demonstrating the excellent generality of the design method in this paper.

关键词： integrated optics inverse design mode splitter

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An Improved Modulation Strategy for Single-phase Three-level Neutral-point-clamped Converter in Critical Conduction Mode

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 981-990页

作者： Ning Li Yujie Cao Xiaokang Liu Yan Zhang Ruotong Wang Lin Jiang Xiao-Ping Zhang School of electrical engineering Xi'an University of Technology the Department of Electronics Information and Bioengineering Xi'an Jiaotong University the Department of electrical engineering and Electronics University of Liverpool the Department of Electronic Electrical and Systems Engineering University of Birmingham

Two-level totem-pole power factor correction(PFC) converters in critical conduction mode(CRM) suffer from the wide regulation range of switching frequency. Besides, in highfrequency applications, the number of switching times increases, resulting in significant switching losses. To solve these issues, this paper proposes an improved modulation strategy for the single-phase three-level neutral-point-clamped(NPC) converter in CRM with PFC. By optimizing the discharging strategy and switching state sequence, the switching frequency and its variation range have been efficiently reduced. The detailed performance analysis is also presented regarding the switching frequency, the average switching times, and the effect of voltage gain. A 2 k W prototype is built to verify the effectiveness of the proposed modulation strategy and analysis results. Compared with the totem-pole PFC converter, the switching frequency regulation range of the three-level PFC converter is reduced by 36.48% and the average switching times is reduced by 45.10%. The experimental result also shows a 1.2% higher efficiency for the three-level PFC converter in the full load range.

关键词： Switches Switching frequency Control systems Topology Bridge circuits Inductors Customer relationship management

Employing electrochemically derived pH gradients for Lab-on-PCB protein preconcentration devices

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Microsystems & Nanoengineering 2024年第1期10卷 79-87页

作者： Grace Maxted Pedro Estrela Despina Moschou Department of Electronic and electrical engineering University of BathBath BA27AYUK centre for Bioengineering and Biomedical Technologies(CBio) University of BathBath BA27AYUK

Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations,such as bodily fluids,water,or wastewater.Nonetheless,very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice,and even fewer have been integrated with other microanalytical steps.Existing approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall assay.In this paper,we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent approaches.In this way,we reduce the need for additional chemical reagents to zero while enabling device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB technology.We apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution in the vicinity of planar electrodes using electrochemical acid generation through redox-active self-assembled monolayers.The presented device comprises a printed circuit board with an array of gold electrodes that were functionalized with 4-aminothiophenol;this formed a self-assembled monolayer that was electropolymerized to improve its electrochemical reversibility.Protein preconcentration was performed in two configurations.The first was open and needed the use of a holder to suspend a well of fluid above the electrodes;the second used microfluidic channels to enclose small volumes of fluid.Reported here are the resulting data for protein preconcentration in both these forms,with a quantitative concentration factor shown for the open form and qualitative proof shown for the microfluidic.

关键词： electrochemical proof qualitative

Multiplexed fluorescence and scatter detection with single cell resolution using on-chip fiber optics for droplet microfluidic applications

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Microsystems & Nanoengineering 2024年第2期10卷 207-218页

作者： Preksha Gupta Ambili Mohan Apurv Mishra Atindra Nair Neeladri Chowdhury Dhanush Balekai Kavyashree Rai Anil Prabhakar Taslimarif Saiyed Discovery Innovation Accelerator Centre for Cellular and Molecular PlatformsBellary RoadBengaluru560065KarnatakaIndia Department of electrical engineering Indian Institute of Technology MadrasChennai600036Tamil NaduIndia

Droplet microfluidics has emerged as a critical component of several high-throughput single-cell analysis techniques in biomedical research and diagnostics.Despite significant progress in the development of individual assays,multiparametric optical sensing of droplets and their encapsulated contents has been challenging.The current approaches,most commonly involving microscopy-based high-speed imaging of droplets,are technically complex and require expensive instrumentation,limiting their widespread adoption.To address these limitations,we developed the OptiDrop platform;this platform is a novel optofluidic setup that leverages the principles of flow cytometry.Our platform enables on-chip detection of the scatter and multiple fluorescence signals from the microfluidic droplets and their contents using optical fibers.The highly customizable on-chip optical fiber-based signal detection system enables simplified,miniaturized,low-cost,multiparametric sensing of optical signals with high sensitivity and single-cell resolution within each droplet.To demonstrate the ability of the OptiDrop platform,we conducted a differential expression analysis of the major histocompatibility complex(MHC)protein in response to IFNγstimulation.Our results showed the platform’s ability to sensitively detect cell surface biomarkers using fluorescently labeled antibodies.Thus,the OptiDrop platform combines the versatility of flow cytometry with the power of droplet microfluidics to provide wide-ranging,scalable optical sensing solutions for research and diagnostics.

关键词： scatter enable resolution