Quick Response Characteristics Research Articles

Design and Feasibility Verification of Novel AC/DC Hybrid Microgrid Structures.

To enhance the power supply reliability of the microgrid cluster consisting of AC/DC hybrid microgrids, this paper proposes an innovative structure that enables backup power to be accessed quickly in the event of power source failure. The structure leverages the quick response characteristics of thyristor switches, effectively reducing the power outage time. The corresponding control strategy is introduced in detail in this paper. Furthermore, taking practical considerations into account, two types of AC/DC hybrid microgrid structures are designed for grid-connected and islanded states. These microgrids exhibit strong distributed energy consumption capabilities, simple control strategies, and high power quality. Additionally, the aforementioned structures are constructed within the MATLAB/Simulink R2023a simulation software. Their feasibility is verified, and comparisons with the existing studies are conducted using specific examples. Finally, the cost and efficiency of the application of this study are discussed. Both the above results and analysis indicate that the structures proposed in this paper can reduce costs, improve efficiency, and enhance power supply stability.

Membrane-Based Electrochemical Detection of Uranium: A Review

The determination of uranium in environmental samples has always been a crucial environmental issue due to its adverse impacts on human life. Electrochemical detection is one of the most suitable methods for directly determining uranium because of its portable instrument and quick response characteristics. The ion-selective membrane in the working electrodes is selectively responsible for uranium transport and separation. This mini-review provides a general overview of the membrane-based ion-selective electrodes in detecting uranium ions reported in the literature. The ion-selective membranes are classified according to their ionophore categories. Furthermore, the limits and outlook are also discussed to provide a reference for further developing membrane-based electrochemical uranium sensors.

A compact strain sensor based on M-shaped-core long-period fiber grating

Optical sensors for strain measurement have been significantly concerned due to their unique characteristics of quick response, anti-electromagnetic interference and compact size. In this article, a brand-new type of “M”-shaped core long-period fiber grating (M-LPFG) based on core-modulated method is proposed and experimentally testified. By means of side-polishing and high-temperature oxyhydrogen flame heating, the cladding of fiber tends to be circular and the core will bend slightly towards the polished area. The micro-bending core is suffered strong refractive index modulation and this phenomenon also excites the evanescent field adequately. By analyzing the simulated light transmission and the transmission spectrum, considerable degree of micro-bending core is achieved. In the experiment, the proposed sensor with 10 periods (5 mm) displays a high strain sensitivity of −19.05 pm/ με with range of 0–500 με, and the temperature sensitivity of which is obtained as 51.16 pm/°C. Due to relatively small influence on cladding and self-circularity of structure, the M-LPFG possesses a high mechanical strength. With the above advantages of high sensitivity, compact size, low-cost and strong mechanical strength, the method of fabricating M-LPFG has great potential in strain measurement.

Retrieving Water Quality Parameters from Noisy-Label Data Based on Instance Selection

As an important part of the "air–ground" integrated water quality monitoring system, the inversion of water quality from unmanned airborne hyperspectral image has attracted more and more attention. Meanwhile, unmanned aerial vehicles (UAVs) have the characteristics of small size, flexibility and quick response, and can complete the task of water environment detection in a large area, thus avoiding the difficulty in obtaining satellite data and the limitation of single-point monitoring by ground stations. Most researchers use UAV for water quality monitoring, they take water samples back to library or directly use portable sensors for measurement while flying drones at the same time. Due to the UAV speed and route planning, the actual sampling time and the UAV passing time cannot be guaranteed to be completely synchronized, and there will be a difference of a few minutes. For water quality parameters such as chromaticity (chroma), chlorophyll-a (chl-a), chemical oxygen demand (COD), etc., the changes in a few minutes are small and negligible. However, for the turbidity, especially in flowing water body, this value of it will change within a certain range. This phenomenon will lead to noise error in the measured suspended matter or turbidity, which will affect the performance of regression model and retrieval accuracy. In this study, to solve the quality problem of label data in a flowing water body, an unmanned airborne hyperspectral water quality retrieval experiment was carried out in the Xiao River in Xi’an, China, which verified the rationality and effectiveness of label denoising analysis of different water quality parameters. To identify noisy label instances efficiently, we proposed an instance selection scheme. Furthermore, considering the limitation of the dataset samples and the characteristic of regression task, we build a 1DCNN model combining a self attention mechanism (SAM) and the network achieves the best retrieving performance on turbidity and chroma data. The experiment results show that, for flowing water body, the noisy-label instance selection method can improve retrieval performance slightly on the COD parameter, but improve greatly on turbidity and chroma data.

On‐Skin Stimulation Devices for Haptic Feedback and Human–Machine Interfaces

AbstractOn‐skin electronics have been widely used in fields, such as wearable healthcare and human–machine interfaces due to their excellent performances and wearable comfort. Among them, on‐skin sensors for collecting signals have been greatly developed, while the stimulators that provide tactile feedback are difficult to achieve in terms of flexibility and stretchability due to their rather complicated structures. Achieving on‐skin stimulators with superior performances and outstanding wearability requires major advances in materials, fabrication, and structure design. The on‐skin stimulator needs to be soft with a lightweight and thin structure so that it can be laminated onto the skin with conformal contact for accurate feedback. Three stimulation modes, namely electrotactile, thermal, mechanotactile, and vibrotactile stimulation, are investigated. Among them, electrotactile stimulation is the characteristics of high resolution and quick response. Thermal stimulation can provide a unique heat sensation without crosstalk with other stimuli. Mechanotactile and vibrotactile stimulation can bring comfortable feedback to skin, showing great potential in wearable applications. This paper summarizes the working principles, materials, structures, and applications of these on‐skin stimulators, and compares their advantages with conventional rigid devices. At the end of this paper, the challenging issues and future prospects in this field are discussed.

Calibration method research and uncertainty evaluation of End-tidal carbon dioxide concentration of Multifunction Patient Monitoring Instruments

The monitoring of end-tidal carbon dioxide concentration has the characteristics of non-invasive and quick response, which has become one of the important ways of clinical vital signs monitoring. This monitoring equipment is widely used in emergency operating room, critical care and other important departments. The calibration of end-tidal carbon dioxide concentration can effectively test the accuracy and safety of equipment, and the research of calibration method and the evaluation of uncertainty are of great significance.

A new combined braking approach of magnetorheological fluids brake based on fuzzy controller and improved PID controller

With the aim to improve working performance of magnetorheological fluids (MRF) brake, a combined braking approach is proposed in this paper. A data acquisition system of MRF brake is designed and transfer function is identified for the device. Furthermore, based on the excitation current-extrusion pressure combined braking system, a fuzzy controller is designed to distribute the target torque. Moreover, through integration of fruit fly optimization algorithm (FOA) and particle swarm optimization algorithm (PSOA), an improved proportional-integral-differential (PID) controller is presented to conduct braking mechanism. Finally, the simulations and experiments are carried out. The results show that the combined braking approach with fuzzy controller and improved PID controller has characteristics of quick response and no overshoot, and superior to conventional PID and FOA PID controller.

Effective location of SMES for power fluctuation mitigation of grid connected doubly fed induction generator

Abstract Utilizing the characteristics of high efficiency and quick response of superconducting magnetic energy storage (SMES), the issues of grid connected wind power generating system (WPGS), like load leveling, voltage instability and power fluctuation can be solved. In this paper, SMES is used to improve the power quality of doubly- fed induction generator (DFIG) based WPGS by mitigating the output power fluctuation. Two cases have been considered by connecting SMES in two different locations in a WPGS integrated grid. In the first case, SMES through a Type-D chopper is connected with the dc side of the conversion system of DFIG. In the second case, SMES is connected at the point of common coupling (PCC). According to the control objectives, SMES in both cases contributes to the stability and reliability of the grid. Using MATLAB/ Simulink, these two models are established, simulated and compared to realize the better location of SMES for effective performance.

Robust Hg0.023WO3 nanoparticles: Synthesis, characterization and application as relative humidity sensing material and photocatalyst for degradation of organic dye contamination

Hg0.023WO3 nanoparticles prepared by economic and tranquil co-precipitation method was characterized by Powder X-Ray diffraction (XRD) for structural analysis, Energy dispersive X-Ray analysis (EDX) for elemental analysis, Scanning electron microscopy for morphology, DLS for particle size analysis, Ultra violet (UV) absorption spectra, Photoluminescence spectra for optical absorption properties, humidity sensor for sensing ability and photocatalytic efficiency by photocatalytic studies. The humidity sensing ability was measured corresponding to resistivity of the prepared material that provides the sensitivity factor (Sf) which was 736 for the synthesized nanoparticles. It was analyzed to have the quick response and recovery characteristics with narrow hysteresis. The Photocatalytic activity was estimated by degradation of Rhodamine B (Rh B) dye using synthesized Hg0.023WO3 nanoparticles under visible light illumination. The degradation rate was found to be high and the efficiency was 98.47% that seem to be wise for the photocatalyst material. Based on validation of the data, the Hg0.023WO3 nanoparticles seem to act as humidity sensor and an excellent photocatalyst.

Self-assembled highly porous rugby-like hierarchical ZnO thin film formaldehyde gas sensor

A new rugby-like ZnO thin film was self-assembled via a hydrothermal method and the influences of the hydrothermal temperature on crystal growth and gas sensing properties of ZnO thin films were investigated. The results showed that the highly porous rugby-like ZnO crystals were self-assembled via thin fan-shape sheets with abundant nanopores formed by interconnected the smaller nanoplates when the hydrothermal temperature was 140 °C. Its specific surface area value reached 45.0 m2 g−1. The sensor exhibited an excellent gas sensing response, a good selectivity towards formaldehyde and quick response characteristics at the optimum working temperature of 250 °C.

A joint optimal dispatching method of wind-solar-hydro generation system

As the first choices among new energy resources to alleviate the crisis of fossil fuels and solve the problem of environmental pollution, wind and solar power generation have attracted more and more attention. However, the instability and intermittency of its output have become the bottleneck restricting its large-scale development. In the system with wind and PV power, conventional energy is often required to reduce the volatility of the output. Due to the characteristics of stable output and quick response to load change, the cascade hydropower station compensates the instability of wind and solar power output. In this paper, a combined generation model including wind power, photovoltaic generation and the cascade hydropower stations has been built and NSGA-II has been used to work out a scheduling scheme, which has been proved to perform better than other algorithms.

Synthesis and gas sensing performance of NiO decorated SnO2 vertical-standing nanotubes composite thin films

In this work, a new type NiO decorated SnO2 vertical-standing nanotubes composite thin film was synthesized successfully via a facile hydrothermal method. The microstructure, physico-chemical surface state and morphology of the composite thin film were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The results showed that the NiO decorated SnO2 vertical-standing nanotubes composite thin film with a coral-like microstructure was built of numerous 1D SnO2 nanotubes with the size of 200–300 nm in diameter and 1.5 μm in length; while NiO nanoplates with the size of 20 nm in diameter decorated on the surface of SnO2 nanotubes. Due to the enhanced adsorption of oxygen molecules, formation of p-NiO/n-SnO2 heterojunction and porous structure, the NiO/SnO2 thin film gas sensor with an Ni2+/Sn4+ molar ratio of 5% exhibited high response value, good selectivity and quick response characteristics to ethanol at the optimum working temperature of 250 ℃.

An Elderly Care System Based on Multiple Information Fusion.

With the development of social economy in the 21st century, and the rising of medical level, the aging of population have become a global trend. However lots of elderly people are in “empty nest” state. In order to solve the problem of high risk of daily life in this group, this paper proposed a method to integrate the information of video images, sound, infrared, pulse, and other information into the elderly care system. The whole system consists of four major components, that is, the main control board, the information acquisition boards, the server, and the client. The control board receives, processes and analyzes the data collected by the information acquisition boards, and uploads necessary information to the server, which are to be saved to the database. When something unexpected occurs to the elderly, the system will notify the relatives through the GPRS (general packet radio service) module. The system also provides an interface for the relatives to inquire the living status of the elderly through an app. The system can monitor the living status for the elderly with the characteristics of quick response, high accuracy, and low cost and can be widely applied to the elderly care at home.

Design and Experiment on Integrated Proportional Control Valve of Automatic Steering System

According to the requirements of tractor automatic steering hydraulic system, a proportional integrated control valve was designed. Based on the non-linearity of the hydraulic system, the state equation of the integrated proportional control valve that works in the open-center hydraulic steering systems was established. With the establishment of the MATLAB/Simulink models, the static and dynamic performance of the integrated proportional control valve were simulated. Furthermore, the indoor test platform was built on the basis of the proposed test scheme, on which the properties of steady flow, load flow and pressure loss of the integrated proportional control valve were analyzed. The simulation and experimental results show that the valve flow can be better to follow the drive voltage; when the spool opening unchanged, load step change, the simulation and test results of the flow is about 10L/min. The differential pressure relief valve pressure compensation performance is better. Finally, the actual test of the proportional integrated control valve is carried out. The experimental results show that the average deviation of the target tracking is less than 2.192° and the maximum deviation is less than 2.44°. The valve proposed in this study performed well referring to the tracing and quick response characteristics, which meets the requirements of tractor navigation control.

Design and Experiment Evaluation of a Rotatable and Deployable Sleeve Mechanism Using a Two-DOF Piezoelectric Actuator

A rotatable and deployable sleeve mechanism using a longitudinal-bending composite piezoelectric actuator was designed, fabricated, and tested. A two-DOF piezoelectric actuator with single driving foot was designed to work as the driver of the deployable sleeve mechanism: it could push the inner sleeve with linear, rotary, or spiral stretching motions, which was controlled easily by applying different exciting signals. The stretching principles of the proposed deployable sleeve mechanism were illustrated in detail and verified by means of the finite element method. A prototype of the two-DOF piezoelectric actuator was fabricated and the deployable sleeve mechanism was assembled. The mechanical output characteristics of the inner sleeve were tested and discussed. The proposed deployable sleeve mechanism achieved the maximum linear and rotary stretching speeds of 530 mm/s and 240 °/s when the voltage amplitudes and exciting frequencies were $300\,\,V_{\mathrm {p-p}}$ and 22.35 kHz. The spiral stretching ability of the deployable sleeve mechanism was validated experimentally. The linear and rotary stretching displacement resolutions of the inner sleeve were tested to be about $2~\mu \text{m}$ and 0.0014°, respectively. The proposed deployable sleeve mechanism obtained quick transient response characteristics with a starting time of 28 ms and a stopping time of 20 ms.

Electrically Conductive Coordination Polymer for Highly Selective Chemiresistive Sensing of Volatile Amines.

A new electrically conductive coordination polymer is synthesized using anthracene-incorporated organic ligand. The compound exhibits a band-like structure and long-range π-π stacking of ligand. Interestingly, the fabricated chemiresisitor using this coordination polymer shows selective sensing behavior for volatile amine detection with characteristics of quick response, good reproducibility, and room-temperature operation. This study not only presents a rare example of electrically conductive coordination polymer but also illustrates the useful application of coordination polymer for chemiresistor.

Magnetoelectric Effect for Rotational Parameters Detection

The magnetoelectric (ME) effect has been successfully demonstrated in the potential device applications of energy harvesters, magnetic sensors, current sensors, microwave and millimeter-wave multiferroic devices, miniature antennas, and even medical applications. To further investigate the role of ME effect in rotational parameters detection, this paper presents an ME rotational parameter sensor consisting of a magnetostrictive/piezoelectric laminated composite (MPLC) and a multi-pole magnetic ring. The relationship between the proposed sensor’s output signal and the rotational parameters has been analyzed. The output frequency is directly proportional to the rotational speed, and the waveform has a good sin property. In a word, based on the proposed sensor, the rotational speed can be measured by determining the frequency of the output signal, and the rotational position can be detected by the phase discrimination. As the MPLC has the characteristics of high sensitivity and quick response, the starting and stopping times and the eccentricity of rotating pieces can also be measured by the proposed ME rotational parameter sensor.

Novel multiwalled carbon nanotube grafted with polyethylene glycol-block-polystyrene nanohybrids: ATRP synthesis and detection of benzene vapor

Novel multiwalled carbon nanotube graft polyethylene glycol-block-polystyrene copolymer nanohybrids (MWCNTs-g-PEG-b-PS) were prepared via atom transfer radical polymerization using carboxylated MWCNTs (MWCNTs–COOH) as a conductive carrier. The chemical structure and the compositions of graft copolymer nanohybrids were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetry, and gas chromatography, and the morphologies and dispersion behavior were observed by ultraviolet visible spectrophotometer, scanning electron microscope, and transmission electron microscope etc. The MWCNTs-g-PEG-b-PS-grafted copolymer nanohybrids were fabricated into conductive composite thin film sensors to investigate their responsiveness to benzene vapor. The influence of the molecular weights or compositional ratios of PEG and PS blocks on the conductivity of the conducting polymer nanohybrids and responsibility towards benzene vapor was investigated. The conducting polymer nanohybrid film sensors were demonstrated to possess the characteristics of quick response and good restorability, repeatability, and stability.

Synthesis and gas sensor application of ZnFe2O4–ZnO composite hollow microspheres

In this contribution, ZnFe2O4–ZnO composite hollow microspheres were successfully synthesized by a glucose-assisted hydrothermal method only using Fe(NO3)3·9H2O, Zn(NO3)2·6H2O and glucose as starting materials, followed by a calcination treatment. The characterization results from scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the as-synthesized ZnFe2O4–ZnO composite hollow microspheres, with a diameter range of 1 to 2.5 μm and a shell thickness of about 60 nm, consist of numerous small cubic spinel ZnFe2O4 nanoparticles and hexagonal wurtzite ZnO nanoparticles. In order to investigate the potential applications, the resulting ZnFe2O4–ZnO composite hollow microspheres were employed to fabricate a gas sensor using four common volatile organic pollutants (VOPs) namely n-butanol, acetone, ethanol and methanol as probe gases. The gas sensing measurement results demonstrated that the sensor based on the as-obtained ZnFe2O4–ZnO composite hollow microspheres exhibited a high response, good reversibility and reproducibility, and quick response and recovery characteristics. The composite sensor also showed enhanced responses compared with the pure ZnO sensor, which could be contributed to the unique rough, porous and hollow structure of the ZnFe2O4–ZnO composite hollow microspheres, and the heterojunction action at the interfaces of ZnFe2O4–ZnO. It is expected that the current ZnFe2O4–ZnO composite hollow microspheres have promising applications in gas sensors and can be further applied in other fields such as photocatalysis and magnetic resonance imaging.

Simulation on Superconducting Magnetic Energy Storage in a Grid-Connected Photovoltaic System

Photovoltaic (PV) generation is widely used to solve energy shortage and environment problem. Since the output current of the solar cell will change with the sunlight irradiation, the power of the solar cells are not stable, so there is a need of a storage equipment connected to the PV system. With the characteristics of high efficient energy storage and quick response of the power exchange, the superconducting magnetic energy storage (SMES) can be used to meet the balance between the grid and the PV. A SMES and PV subsystem are connected together with the DC bus, which have less power electronics elements and can control power quality efficiently than linked with the AC bus. This hybrid system is composed of a DC/AC converter on the grid side, a DC/DC converter with the PV arrays, and a DC chopper with the superconducting magnet. A detailed model of the hybrid system is built with MATLAB/SIMULINK. Simulation results with and without SMES connected to the grid-connected photovoltaic system are presented, compared, and analyzed. The results of simulation demonstrate that the SMES system can maintain the DC bus as a constant value which can contribute to the stability and reliability of the grid-connected PV system.