Current Principle Research Articles

Enabling High‐Rate and Long‐Cycling Zinc–Air Batteries with a ΔE = 0.56 V Bifunctional Oxygen Electrocatalyst

AbstractZn–air batteries (ZABs) are promising next‐generation energy storage devices due to their low cost, intrinsic safety, and environmental benignity. However, the sluggish kinetics of the cathodic reactions severely limits the ZAB performances in practical use, calling for high‐efficiency bifunctional oxygen reduction and evolution electrocatalysts. Herein, an ultrahigh‐active bifunctional electrocatalyst is developed with a record‐low ΔE of 0.56 V, significantly outperforming the noble‐metal‐based benchmark (Pt/C+Ir/C, ΔE = 0.77 V) and many other reported bifunctional electrocatalysts (mostly ΔE ≥ 0.60 V). The nanoscale composite of Fe‐based single‐atom sites and nanosized layered double hydroxides endows the bifunctional electrocatalyst with high conductivity and a large active surface that afford strengthened electron conduction and ion transport pathways. Furthermore, a remarkable improvement in stability is realized following the current division principle. ZABs with the bifunctional electrocatalyst deliver a high peak power density of 198 mW cm−2 and excellent cycling durability for over 6000 cycles. Moreover, ampere‐hour‐scale ZABs are constructed and cycled under 1.0 A and 1.0 Ah conditions. This work breaks the activity record for bifunctional oxygen electrocatalysis and expands the potential of ZABs for sustainable energy storage.

Structural Modification Strategy for Enhancing Electrochemical Performance of Electrodes Under High Current Cycling and First Principle Computational Research for Electrode Materials

Recently, there has been significant interest in advancing lithium-ion battery technology due to its widespread use in various applications. Our research delves into this domain, focusing on enhancing the electrochemical properties of batteries through structural modification of electrode materials. Our work demonstrates the significant enhancements of electrochemical performance under high current cycling using structurally modified electrode materials . In first work, crumpled graphene oxide anode proves to be an effective strategy for enhancing its electrochemical properties, attributed to its advantageous crumpled morphology. This morphology allows for improved electrode stability and easier access for lithium ions, enabling them to interact with its larger specific surface area. In second work, we describe enhanced the drawback of reduced electrochemical performance during high-rate cycles by synthesizing multidimensional LFP-based carbon composite. The lithium ion diffusivity and electrode stability of the prepared composite are significantly improved in charging and discharging cycles by introducing graphene quantum dots alongside CNTs, exhibiting superior electrochemical properties even at high current densities. In third work, density functional theory simulation is employed for demonstrating the enhanced electrochemical properties of prepared electrodes by exploring their properties. Our research provides insights into electrode material design as an effective approach to enhancing the electrochemical properties of lithium-ion batteries.Acknowledgement:This work was supported by the National Research Foundation of Korea (NRF-2021R1A2C1008272). This work was supported by Ministry of Trade, Industry and Energy, KEIT, under the project title"International standard development of evaluation methods for nano-carbon-based high-performance supercapacitors for electric vehicles" (project # 20016144).

Elucidation of the mechanism underlying the sequential catalysis of inulin by fructotransferase

Glycoside hydrolase family 91 (GH91) inulin fructotransferase (IFTases) enables biotransformation of fructans into sugar substitutes for dietary intervention in metabolic syndrome. However, the catalytic mechanism underlying the sequential biodegradation of inulin remains unelusive during the biotranformation of fructans. Herein we present the crystal structures of IFTase from Arthrobacter aurescens SK 8.001 in apo form and in complexes with kestose, nystose, or fructosyl nystose, respectively. Two kinds of conserved noncatalytic binding regions are first identified for IFTase-inulin interactions. The conserved interactions of substrates were revealed in the catalytic center that only contained a catalytic residue E205. A switching scaffold was comprised of D194 and Q217 in the catalytic channel, which served as the catalytic transition stabilizer through side chain displacement in the cycling of substrate sliding in/out the catalytic pocket. Such features in GH91 contribute to the catalytic model for consecutive cutting of substrate chain as well as product release in IFTase, and thus might be extended to other exo-active enzymes with an enclosed bottom of catalytic pocket. The study expands the current general catalytic principle in enzyme-substrate complexes and shed light on the rational design of IFTase for fructan biotransformation.

Self-Adaptive Resonance Technology for Wireless Power Transfer Systems to Eliminate Impedance Mismatches

Impedance mismatching can severely decrease the power transmission capacity or even invalid the control logic of wireless power transfer (WPT) systems. To eliminate the impedance mismatch caused by various factors, such as resonant parameter drift, coupling structure misalignment and control strategy, a self-adaptive mistuning correction circuit and corresponding parameter design rules are proposed to ensure the WPT system consistently operates under resonant state, accompanying the optimal power transfer ability. Moreover, a reactive compensation circuit that can create an auxiliary voltage source by the absorbed reactive power that is introduced by impedance mismatching is designed. This source can generate a new current on the coil to bring the mismatched input current back to the resonant state, according to the current superposition principle. Unlike passive impedance network that require high parameter precision and active impedance matching strategies equipped with detection and control circuits, the proposed approach can self-adaptively eliminate either undesired capacitive or inductive reactance with two additional switches and an energy-storage capacitor, improving impedance adjusting rate and providing better system robustness. The simulations and experiments are in good agreement with the theoretical analysis. This study has potential applications in harsh environments where the system impedance and coupling strength are continuously disturbed.

Farmers’ evolving attitudes on environmental conditionality in the CAP: a farm level examination of temporal shifts

AbstractGiven the anticipated shift in the allocation of resources under the common agricultural policy (CAP) toward increasing positive environmental outcomes, this study explores farmer attitudes toward the current principle of connecting direct payments to environmental conditionality, known as cross compliance. Furthermore, we explore whether there have been changes in farmer attitudes toward cross compliance over time by posing identical questions to farmers in both 2010 and 2018. A supplementary survey was designed and administered in conjunction with the core EU Farm Accountancy Data Network (FADN) to assess farmers’ attitudes to linking CAP payments to environmental conditionality. The findings of a generalized ordered logit model indicate a high level of support among farmers for linking direct payments to good agricultural practices and cross compliance standards. Factors influencing farmers’ acceptance of cross compliance can be categorized into several domains, including farm and farmer characteristics, social and institutional attributes, and economic factors. Notably, the level of subsidy dependency emerges as a highly significant factor, with farmers who rely more heavily on direct payments being more inclined to disagree with cross compliance requirements.

Expanding the time-interleaving design capabilities: A 28 GS/s 4-bit time-interleaved current-steering DAC case study

In this work, a novel approach of designing high-speed time-interleaved Digital-to-Analog Converters (DACs), that exploits high-order time-interleaved factors, was proposed. The presented time-interleaving design approach is based on the current superposition principle, capable of expanding the time-interleaved factor of DACs without compromising the conversion linearity and accuracy. For the validation of the proposed design approach, a 28 GS/s 4-bit 4 × Time-Interleaved current-steering DAC was designed using a 22 nm Fully-Depleted Silicon-On-Insulator (FDSOI) CMOS process node. Post-layout simulations were carried out by developing a custom, hybrid RC/RLCk parasitic extraction methodology, capable of capturing all possible layout parasitic effects due to the high conversion speed of the designed DAC. Using the proposed approach, the designed time-interleaved DAC was capable of achieving ENOB>3.83 bits, SFDR>28.7 dBc for fin≤1.75 GHz, with no missing codes and a low power consumption of Pdiss=3.1 mW/core.

A differential current based protection scheme for DC microgrid

A continuous increase in greenhouse emissions has led to more frequent use of renewable energy resources. The increased emergence of DC loads in day-to-day lives has further led to conversion to DC distribution lines. In prospect of getting more environmentally friendly, economical, and reliable power delivery a DC micro grid was developed and has become more common in recent years. The disaster management cell located at the Department of Electrical and Electronics Engineering has designed a DC micro grid which consists of sources provided from the grid, a battery bank, and an array of solar cells supplying to a set of nine loads, which are segregated into three sets of three loads each. This paper presents a protection scheme for the buses present in a micro grid that is based on the differential current principle. It is done with the help of a centralized protection controller that enables fault identification and fault isolation. This protection scheme is further extended to a DC ring-bus micro grid, where the centralized protection controller enables fault identification, fault location, and fault isolation. MATLAB/Simulink is used to obtain the simulation and verify the results.

Effect of Mechanical Alloying Time on Microstructure, Hardness and Electrical Conductivity Properties of Cu-B4C Composites

This study aims to investigate the effect of mechanical alloying time on the microstructure, hardness, and electrical conductivity properties of copper (Cu) matrix boron carbide (B4C) reinforced composites. Cu-B4C composites with 2% B4C by volume were subjected to mechanical alloying processes for 0, 1, 5, 10, and 20 hours. The microstructure and phase formation of the composites were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Hardness measurements of the composites were conducted using the microhardness measurement method, and density values were determined using the Archimedes principle. The electrical conductivity values of the samples were measured in terms of the international annealed copper standard (%IACS) based on the eddy current principle. SEM images revealed a more homogeneous distribution of B4C particles in the Cu matrix as the mechanical alloying time increased. Hardness values showed significant increases with the increasing mechanical alloying time, reaching the highest value in the 20 h milled sample with a 90.86 value. The effect on electrical conductivity values was noteworthy, with a measurement of 63% IACS at 0 hours and 25% IACS at 20 hours of mechanical alloying.

Steady-state selection in multi-species driven diffusive systems

We introduce a general method to determine the large-scale non-equilibrium steady-state properties of one-dimensional multi-species driven diffusive systems with open boundaries, generalizing thus the max-min current principle known for systems with a single type of particles. This method is based on the solution of the Riemann problem of the associated system of conservation laws. We demonstrate that the effective density of a reservoir depends not only on the corresponding boundary hopping rates but also on the dynamics of the entire system, emphasizing the interplay between bulk and reservoirs. We highlight the role of Riemann variables in establishing the phase diagram of such systems. We apply our method to three models of multi-species interacting particle systems and compare the theoretical predictions with numerical simulations.

The Influence of Blade Structure Optimization on the Hydraulic Performance of Vane Pump

Vane pump has the problems of low pressure reduction efficiency and easy to be stuck at the bottom of the well. In order to solve this problem, the annular pressure reduction downhole tool of vane pump based on eddy current principle is adopted. On the basis of introducing the principle of eddy current hydraulic pressure reduction technology, this paper studies the influence of blade number, blade outlet angle, blade chord height and blade thickness on tool characteristics. The results show that the tool head increases with the increase of blade number, increases first and then decreases with the increase of blade outlet angle, and decreases first and then stabilizes with the increase of blade wall thickness and chord height. The tool efficiency increases with the increase of blade number, decreases with the increase of blade chord height, and decreases with the increase of blade outlet angle to a certain value, which is less sensitive to blade wall thickness. The research results have important guiding significance for the design and structural optimization of blade annular pressure reducing tools.

San Min and its Spencerian origin

PurposeThe aim of this article is two-fold. First, it offers a unique account of San Min, the prototype of the current Chinese educational principle proposed by Yan Fu (1854–1921) that aimed at improving people’s physical, intellectual and moral capacities. This system of educational thinking has received only marginal attention in Anglophone research literature. Second, given the influence of Yan Fu’s interpretation and promulgation of Herbert Spencer’s educational philosophy during that period, it investigates the extent to which San Min is derived from Spencer’s educational thought (the “Spencerian Triad”). This article focusses on how Yan Fu adapted the ideas of San Min from Spencer’s account.Design/methodology/approachThis article considers Yan Fu’s principle of San Min in relation to Spencer’s educational triad through a close reading and comparison of key primary texts (including Yan Fu’s original writing). It explores the similarities and differences between each account of education’s goals and its proposed means of attainment.FindingsYan Fu’s principle of San Min is shown to have been adapted from the Spencerian Triad. However, using the theory of Social Organism, Yan Fu re-interpreted Spencer’s individual liberty as liberty for the nation. While Spencer’s goal was to empower individuals, Yan Fu aimed to serve collective independence, wealth and power.Originality/valueThis article addresses oversights concerning San Min’s Western origins in the Spencerian Triad and its influence on Chinese education under Yan Fu’s sway. It is significant because San Min is still at the core of the current Chinese educational policy.

Fault current limiter principle by switching magnetic circuit

AbstractSeveral types of fault current limiters have been studied so far, including superconductor based one or nonsuperconductor based one. However, it is difficult to satisfy all requirements for cost, maintainability, and current limiting performance. This study proposes another type of fault current limiter, variable transformer based one. It is supposed to be less expensive and easier to be maintained since it is based on the conventional transformer, and to be expected better current limiting performance since the magnetic circuit of the transformer is drastically changed. The magnetic circuit of the transformer is switched to be opened and to produce another one by shifting a portion of its iron core mechanically, allowing the primary and secondary electric circuit to be magnetically isolated. In that way, the electromotive force of the secondary winding could be reduced so that the secondary current could be limited. The prototype based on this concept was designed and built up, and its stational performance has been investigated. As a result, it was confirmed that the prototype shows good current limiting performances identical to the results of the previous FE analysis. Furthermore, the prototype was connected to the operating mechanism to investigate the transient performances, and as a result, satisfying current limiting performances are confirmed

Microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings on the Cu substrate surface by plasma spray method

In this study, the microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings produced on Cu substrates by plasma spray method were investigated. In order to achieve this aim, SiC and WCCo powders were added to copper at different rates such as 5 %, 10 % and 20 % by weight. In order to determine the microstructure properties and phase distribution of the produced coatings, optical microscope, SEM-EDS and XRD analysis were investigated. The reciprocating wear method was used in order to determine the wear properties and the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods was used to determine the corrosion properties. The electrical conductivities of the coating layers were performed according to the eddy current principle. XRD analysis results showed that in both coating types, ceramic particles decomposed in the plasma flame and as a result, binary and ternary metallographic phases were formed. There were significant increases in hardness by adding ceramic particles to Cu, especially with 20 % WCCo additive, the hardness obtained was 82 % higher than the Cu substrate. When the wear properties were examined, both abrasive/adhesive wear types were observed in the copper substrate and coating layers. In all samples, material loss increased as the load increased. Both EIS measurements and Tafel curve results showed that the Cu-5% WCCo coating had the best corrosion resistance among the coatings. When the electrical conductivity results of all samples were compared, the electrical conductivity decreased with increasing rate of carbide in the coating.

Miniaturized centrifugation accelerated pipette-tip matrix solid-phase dispersion based on poly(deep eutectic solvents) surface imprinted graphene oxide composite adsorbent for rapid extraction of anti-adipogenesis markers from Solidago decurrens Lour

Overweight and obesity are the causes of many diseases and have become global "epidemics". Research on natural active components with anti-adipogenesis effects in plants has aroused the interest of researchers. One of the most critical problems is establishing sample preparation and analytical techniques for quickly and selectively extracting and determining the active anti-adipogenesis components in complex plant matrices for developing new anti-adipogenic drugs. In this study, a new poly(deep eutectic solvents) surface imprinted graphene oxide composite (PDESs-MIP/GO) with high selectivity for phenolic acids was prepared using deep eutectic solvents as monomers and crosslinkers. A miniaturized centrifugation-accelerated pipette-tip matrix solid-phase dispersion method (CPT-MSPD) with PDESs-MIP/GO as adsorbent, coupled with high-performance liquid chromatography, was further developed for the rapid determination of anti-adipogenesis markers in Solidago decurrens Lour. (SDL). The established method was successfully used to determination anti-adipogenesis markers in SDL from different regions, with the advantages of accuracy (recoveries: 94.4-115.9%, RSDs≤9.8%), speed (CPT-MSPD time: 11min), selectivity (imprinting factor: ∼2.0), and economy (2mg of adsorbent and 1mL of solvents), which is in line with the current advanced principle of "3S+2A" in analytical chemistry.

A Novel Low-Winding-Loss Circulated Interleaving Structure for Planar Transformers Based on Current Invariance Principle

A Novel Low-Winding-Loss Circulated Interleaving Structure for Planar Transformers Based on Current Invariance Principle

Innovation of classroom teaching of chemical principles based on big data in BOPPPS teaching model

Abstract Classroom teaching mode is an important factor affecting classroom quality and students’ performance. The use of science and technology combined with advanced teaching concepts to rationalize classroom teaching innovation and change has become a research hotspot in the field of education. In this paper, we use the BOPPPS teaching mode on the basis of big data technology to promote teaching innovation in the existing classroom teaching chemical principles. Using a questionnaire survey to study the teaching status of chemical principles in a city university, it is found that the current chemical principle classroom teaching is generally characterized by the problems of solidified teaching mode design, single teaching evaluation method, random design of teaching objectives, etc. The BOPPPS model is applied to the teaching of chemical principles at a city university. The BOPPPS model is applied to the teaching practice of chemical principles in a university, and the student’s classroom performance before and after the change of teaching mode shows obvious differences. After the experiment, 64.17% of the students expressed hope that the BOPPPS teaching model could be promoted in other disciplines. Cluster analysis of students’ performance before and after the experiment using an optimized K-means clustering algorithm shows that the performance of the seven students extracted from the experiment significant improvement after the experiment. The use of the BOPPPS teaching mode makes the students’ score range increase from 60-70 before the test to 80-90 after the test.

Fault Current Limiter Principle by Switching Magnetic Circuit

Fault Current Limiter Principle by Switching Magnetic Circuit

PESTLE Analysis and Sustainable Event Marketing - Evidences from Mount Kinabalu International Climbathon Destination, Borneo

As an industry practitioner, this research strives to explore and engage in intellectual discourse on the current theoretical paradigm practice of sustainable marketing efficiency strategy design for tourism, hospitality establishments, and event staging from the viewpoints of Destination management organisations (DMOs). Critically, this industry-academic writing is committed to contributing to a better interpretation and, possibly, an assessment of the current marketing principle application by highlighting a potential gap between theory (academic) and practice (industry), accompanied by recommendations on holistic marketing, thereby bridging between conventional and sustainable marketing. A systematic qualitative review using explorative content analysis combined with PESTLE feasibility studies of the destination. Approximately 60 journals, book chapters, and relevant newspaper topics, including pertinent literatures, were screened for analysis. The PESTLE approach to DMOs marketing covers direction, product, service, positioning, branding, and niche segmentation. It also explores Muslim-friendly marketing ideas and their role in compelling destination and event hospitality management. The findings provide analytical perspectives of future hallmarks events for developing countries. Furthermore, it presents a distinct and explicit sustainable marketing policy for event marketers, event organisers, DMOs, and relevant bodies to embed sustainable marketing strategy execution in the event hospitality segment. Additionally, it includes an illustration of a sustainable framework for the future Mount Kinabalu International Climbathon (MKIC) event, recommended to the respective DMOs and event organisers.Keywords: Sustainable Marketing Plan; Marketing Design; Destination Management Organisations DMOs; Mount Kinabalu International Climbathon Event (MKIC); PESTLE analysis.

A Dual Function Coating Thickness Measuring Device

In engineering applications, the harsh external environment leads to the erosion of the surface of the tower. The existence of the coating layer provides better protection for the tower, but the uniformity of the thinness and thickness of the coating layer has a great impact on the performance of the material. In this paper, a dual-function tower coating thickness measurement device is designed. The device can automatically measure the thickness of the coating layer by magnetic induction or eddy current thickness measurement principle for the towers with magnetic or non-magnetic materials. The small prototype experiments show that the average error of the measurement of the non-magnetic substrate is only 0.74%, and the average error of the measurement of the magnetic substrate is only 6%, and it has the characteristics of low cost and long service life.

A New Design Technique for a High-Speed and High dV/dt Immunity Floating-Voltage Level Shifter

This paper presents a high-speed level shifter with about 500 V/ns power supply slew immunity. In this designed structure, a narrow pulse-controlled current source is adapted to accelerate the voltage conversion and reduce the power consumption. A Fast-Slewing Circuit speeds up the operation of the level shifter based on the current comparison principle. Edge detection technology is used to filter the generated voltage noise and achieve high dV/dt immunity. The proposed level shifter simulated with the 0.18 μm BCD (bipolar-CMOS-DMOS) process shows fast responses with a typical delay of 1.49 ns and 500 V/ns dV/dt immunity in the 200 V high-voltage application, which only occupies a 0.022 mm2 active area with the 0.18 μm BCD process.