Simple Structure Research Articles

A bidirectional power converter connecting electric vehicle battery and DC microgrid

One way to increase electric vehicle (EV) battery utilization is to connect it to a dc microgrid. The EV battery can assume the role of an energy storage from the grid point of view. A bidirectional DC-DC converter will be needed to transfer power between them back and forth. This paper proposes the converter design considering its functional objective, including interleaved phase number determination. Efficiency performance evaluation is presented by power loss analysis with the parasitic-parameters consideration of the components. Finding optimum switching frequency based on power loss analysis is performed independently between input and output sides of the converter. Finally, experiments using a scaled-down prototype are shown to verify the analytical analysis of the converter. The experimental results properly validate the power loss analytic analysis carried out in this paper with a maximum error of 2.04% at 1131-watt, 60 V battery voltage, and 140 V grid voltage. Maximum efficiency 96.97% is obtained at 301-watt, 130 V battery voltage, and 151 V grid voltage. Overall, the converter has a simple structure, capable to be operated in various levels of input and output voltages with a minimum battery side current ripple.

Electronic Effect Driven Specific and Sensitive Recognition toward GHB.

Precise detection of a trace substance that intrinsically possesses weak chemical activity and less-distinctive spatial structure is of great significance, but full of challenges, as it could not be effectively recognized via either an active covalent reaction process or multiple noncovalent interactions toward its simple structure. Here, the electronic-effect-driven recognition strategy was proposed to visually sense an illicit drug, γ-hydroxybutyric acid (GHB), which was treated as an analyte model due to its inherent simple structure. In particular, a sensing system composed of two probes substituted by the nitro (-NO2) and the hydrogen (-H), was constructed with the characteristic yellow coloring and blue fluorescence, as well as high sensitivity (0.586 ng/mL), fast response (0.2 s), and specific recognition, even in the presence of 22 interferents. In addition, a portable eyeshadow box-like sensing chip was fabricated and proven to be reliable and feasible in sensing GHB disguised in liquors for self-protection in a covert manner. Hence, this work developed an electronic-effect-driven modulation strategy of the recognition interaction between the probe and the analyte and, thus, would open up a new thought for detecting the analyte with weak activity and a simple structure, as well as propel the relevant application in real scenarios.

Quinuclidine N-oxygenation mediated by flavin-containing monooxygenase (FMO) 1 and FMO3 in kidney and liver microsomes from humans, monkeys, dogs, and pigs.

Flavin-containing monooxygenases (FMOs) are a family of enzymes that are involved in the oxygenation of heteroatom-containing molecules. In humans, FMO3 is the major hepatic form, whereas FMO1 is predominant in the kidneys. FMO1 and FMO3 were also identified in monkeys, dogs, and pigs. The predicted contribution of human FMO3 to drug candidate N-oxygenation could be estimated using the classic base dissociation constants of the N-containing moiety. A basic quinuclidine moiety was found in the natural quinine and medicinal products. Consequently, N-oxygenation of quinuclidine was evaluated using liver and kidney microsomes from humans, monkeys, dogs, and pigs as well as recombinant FMO1, FMO3, and FMO5 enzymes. Experiments using simple reversed-phase liquid chromatography with fluorescence monitoring revealed that recombinant FMO1 mediated quinuclidine N-oxygenation with a high capacity in humans. Moreover, recombinant FMO1, FMO3, and/or FMO5 in monkeys, dogs, and pigs exhibited relatively broad substrate specificity toward quinuclidine N-oxygenation. Kinetic analysis showed that human FMO1 efficiently, and pig FMO1 moderately, mediated quinuclidine N-oxygenation with high capacity, which is consistent with the reported findings for larger substrates readily accepted by pig FMO1 but excluded by human FMO1. In contrast, human FMO3-mediated quinuclidine N-oxygenation was slower than that of the typical FMO3 substrate trimethylamine. These results suggest that some species differences exist in terms of FMO-mediated quinuclidine N-oxygenation in humans and some animal models (monkeys, dogs, and minipigs); however, the potential for quinuclidine, which has a simple chemical structure, to be inhibited clinically by co-administered drugs should be relatively low, especially in human livers. Significance Statement The high capacity of human flavin-containing monooxygenase (FMO) 1 to mediate quinuclidine N-oxygenation, a basic moiety in natural products and medicines, was demonstrated by simple reversed-phase liquid chromatography using fluorescence monitoring. The substrate specificity of FMO1 and FMO3 toward quinuclidine N-oxygenation in monkeys, dogs, and pigs was suggested to be relatively broad. Human FMO3-mediated quinuclidine N-oxygenation was slower than trimethylamine N-oxygenation. The likelihood of quinuclidine, with its simple chemical structure, being clinically inhibited by co-administered drugs is relatively low.

Impact factor on the measurement stability of Roche's coil

Compared with the traditional electromagnetic current sensor, Roche coil has advantage in no magnetic saturation phenomenon, simple structure, and has been widely used in current measurement. However, the measurement accuracy, bandwidth and sensitivity of Roche coils are still affected by a variety of factors, and the problem in ensuring the stability of the measurement system of Roche coils still remains to be a problem nowadays. This article is a review of how each factor affects the measurement stability of Rochester coils. In addition, Roche coils also have certain limitations, such as not being able to directly measure the size of the DC current for the principle of current mutual inductance , in order to make Roche coils to obtain a wider range of applications, this article mentions the zero-drift adjustment method, the method of AC superposition, the use of differential coils, and the method of the Hall effect sensor, which are of guiding significance for the future design of Roche coils capable of measuring DC currents.

Rectangular extended neck Helmholtz resonant acoustic structure for low frequency broadband sound absorption

Abstract The Helmholtz resonant structure with a rectangular extended neck is designed in this work to solve the low-frequency broadband sound absorption problem. Theoretical and finite element absorption models have been established and are used for low-frequency acoustic design. What makes it interesting is that all parameters of the rectangular extended neck Helmholtz resonator can be adjusted to shift the working frequency. Four coupling structures with different neck depths, neck opening areas, cavity cross-sectional areas, and cavity depths are respectively designed. Each of these structures exhibits multiple sound absorption coefficient peaks to enhance the low-frequency absorption capacity. The effectiveness of the coupling structure is further analyzed by examining the broadband acoustic absorption mechanism based on the particle vibration velocity distribution. It is found that cells with different acoustic impedance contribute differently to the sound absorption, and cells with longer necks provide better noise reduction at low frequencies. The experiment is verified in the impedance tube, and the result shows that the coupling structure with 9 cells and a cavity depth of only 4cm achieves an average sound absorption coefficient above 0.8 at 210-340 Hz, thus verifying the accuracy of the theoretical model. Overall, the Helmholtz resonant cavity acoustic structure with a rectangular extended neck proposed in this study has a simple structure with low-frequency broadband acoustic absorption performance, providing a new approach for designing low-frequency broadband acoustic structures.

My favourite flowering image: the remarkable inside-out flowers of Lacandonia

Abstract Flowers are deceptively simple structures, characterized by a determinate primary axis that bears organs in condensed concentric zones in a strict structural and temporal sequence. Few species have escaped these constraints, but those that have can provide insights into the evolutionary history of flowers if placed in the appropriate phylogenetic and developmental context. For my flowering image, I selected a longitudinal section of a Lacandonia flower, which breaks a fundamental rule of spatial arrangement: the flowers are ‘inside-out’, with the carpels surrounding the stamens—a pattern that is almost unique among angiosperms. When viewed in the context of the family and order to which it belongs, this species has led me into many fascinating areas of comparative and evolutionary plant morphology.

19.36% Efficiency Organic Solar Cells Based on Low‐Cost Terpolymer Donors with Simple Molecular Structures

AbstractLow cost and high performance are key elements for the industrialization of organic solar cells (OSCs). In view of this, developing highly‐efficient organic photovoltaic molecules with simple chemical structure is one of the most effective countermeasures. Herein, three simple‐structure terpolymers PTQ12‐5, PTQ12‐10, and PTQ12‐15 are designed and synthesized, by embedding difluoro‐substituted bithiophene (2T‐2F) unit into the backbone of low‐cost and high‐efficiency polymer PTQ10. The synthesis of three terpolymers contains only two‐step synthetic routes and over 85% synthetic yields from cheap raw compounds, thus exhibiting distinctly low‐cost characteristic. Remarkably, PTQ12‐5 shows significantly higher absorbance coefficient and hole mobility than PTQ10. Consequently, PTQ12‐5‐based OSCs shows more efficient exciton dissociation and charge transfer, suppressed carrier recombination, tighter molecular π‐π stacking, and faster and more balanced charge transport, thus demonstrates a significantly improved efficiency of 18.77% than that of PTQ10‐based device (18.03%). Moreover, an outstanding efficiency of 19.36% is achieved in PTQ12‐5‐based ternary device by further modulating the energy level alignment and blending features of photoactive molecules, which is the highest efficiency of OSCs based on low‐cost polymers to date. This work has significant implications for guiding the design of low‐cost and high‐performance organic photovoltaic materials.

Adaptive output feedback control system design for nonlinear systems via neural networks

AbstractAdaptive output feedback control based on output feedback exponential passivity (OFEP) has a simple structure and strong robustness in regard to disturbances and system uncertainties. However, it is difficult for most nonlinear systems to satisfy the conditions of OFEP. Thus, the introduction of a suitable parallel feedforward compensator (PFC) to construct an OFEP‐augmented system with the controlled system has been used, but the control output cannot achieve perfect tracking because of the output of the introduced PFC. As a solution, introducing a feedforward (FF) input to build a 2 degree of freedom (2‐DOF) is a simple and effective way to solve this problem. In this paper, we propose the design schemes for suitable PFC and FF input of nonlinear systems via the use of neural networks (NN), respectively. Besides, to cope with possibly present input disturbances, we also provide a method to achieve disturbance compensation based on NN to reduce their interference. Finally, the effectiveness of all proposed design schemes is confirmed through numerical simulations.

Improved magnetic-based apparatus enables non-destructive and high sensitive steel-bar corrosion detection

Steel-bar corrosion can not only induce corrosion cracking, but also cause the bearing capacity decline of concrete structures. This contribution reported an improved magnetic-based steel bar corrosion detection apparatus with simple structure and high accuracy. Accelerated corrosion tests on steel rebar were carried out to calibrate the accuracy of the magnetic-based corrosion detection apparatus. A parameter of sensitivity coefficient, k, was proposed to evaluate the corrosion detection sensitivity of the apparatus. An equivalent numerical model was established based on multi-physical simulation to quantify the corrosion degrees and explore the impacts of the frame internal structural parameters. Results show that k is stable and changes linearly with the diameter of steel rods tested. Increasing frame width and foot length can increase k, and adding extra calibration magnetic circuits leads to reduction in k. Overall, the modified magnetic-based apparatus provides a simple, reliable, accurate and non-destructive method for steel corrosion detection.

Synthesis and application of a novel fluorescent probe based on benzothiazole for detection of hydrazine in real samples

ABSTRACT A novel fluorescence enhancement type probe 2-(1, 3-benzothiazol-2-yl)-5-(diethylamino)phenyl thiophene-2-carboxylate (PTN) for the detection of hydrazine (N2H4) was designed and synthesised. The fluorescence of the probe PTN solution increased dramatically upon the addition of N2H4 and its appearance changed from nearly colourless to dazzling blue. The simple structure and readily available fluorescent probe provide a novel approach for the quantitative detection of N2H4 in the linear range from 0 to 37.5 μM, with a detection limit down to 56 nM, fast response (within 5 min), strong anti-interference ability, easy operation (test paper), and a wide range of pH from 6 to 10. Furthermore, the probe PTN was able to detect N2H4 in actual water samples and image the exogenous N2H4 signal in colorimetric test strips and living zebrafish.

Naphthyl‐Based Chalcone Derivatives: A Multifaceted Player in Medicinal Chemistry

AbstractResearch has placed a great deal of emphasis on molecule development and discovery with substantial biological profiling in recent years. Despite the significant side effects, medicinal chemists have long strived to synthesize drug molecules with the highest level of therapeutic activity and the lowest possible level of toxicity. The naphthyl‐based chalcone derivatives have drawn attention due to their simple structures and wide range of pharmacological effects. The main focus of this review is to outline the biologically active molecules based on naphthyl moiety‐substituted chalcone derivatives developed over the years. A synopsis of pharmacological screening, including relevant structure‐activity relationships, action mechanisms, and possible therapeutic applications, is provided in this article. It is true that prospective hybrids combining the naphthyl moiety with different chalcone pharmacophores are needed to address drug resistance and improve specificity. Therefore, this review may be useful in the development and design of new, highly successful therapeutic drugs based on previously reported methodologies.

Using Unmanned Aerial Vehicles and Multispectral Sensors to Model Forage Yield for Grasses of Semiarid Landscapes

Forage yield estimates provide relevant information to manage and quantify ecosystem services in grasslands. We fitted and validated prediction models of forage yield for several prominent grasses used in restoration projects in semiarid areas. We used field forage harvests from three different sites in Northern Utah and Southern California, USA, in conjunction with multispectral, high-resolution UAV imagery. Different model structures were tested with simple models using a unique predictor, the forage volumetric 3D space, and more complex models, where RGB, red edge, and near-infrared spectral bands and associated vegetation indices were used as predictors. We found that for most dense canopy grasses, using a simple linear model structure could explain most (R2 0.7) of the variability of the response variable. This was not the case for sparse canopy grasses, where a full multispectral dataset and a non-parametric model approach (random forest) were required to obtain a maximum R2 of 0.53. We developed transparent protocols to model forage yield where, in most circumstances, acceptable results could be obtained with affordable RGB sensors and UAV platforms. This is important as users can obtain rapid estimates with inexpensive sensors for most of the grasses included in this study.

Research on the kinetics characteristics and in-cylinder combustion of opposed rotary piston engine for different power output modes

As a new type of internal combustion engine, opposed rotary piston (ORP) engine has the advantages of simple structure and high working frequency, and can achieve high power density. Consequently, it stands as an ideal power source for hybrid power systems and unmanned aerial vehicles. The ORP engine has different power output modes, corresponding to different piston rotation and volume evolutions of combustion chamber. However, the effect of power output modes on kinetics characteristics and in-cylinder combustion of ORP engines are still uncovered. In this paper, the kinematic model of an ORP engine is established for scenarios involving power output by different shafts (Shaft 1 and Shaft 3). Meanwhile, the piston rotation patterns and cylinder volume variations are investigated correspondingly. Further, three-dimensional numerical model of the ORP engine is established, enabling analysis of in-cylinder combustion characteristics, engine performance, as well as nitrogen oxides (NOx) emissions. The results indicate that the volume variations of all cylinders follow a consistent pattern under the power output by Shaft 3. A pair of opposed cylinders features longer durations of intake and expansion strokes, and shorter durations of compression and exhaust strokes, the other pair of combustion chambers is the opposite under the power output by Shaft 1. The engine demonstrates a charging efficiency of 95.36 %, with corresponding indicated thermal efficiency and indicated power output of 38.08 % and 40.9 kW, respectively. The two adjacent cylinders present significantly different operation processes in the case of the power output by Shaft 1, achieving charging efficiencies of 94.29 % and 89.11 %, respectively, with the indicated thermal efficiency of 34.49 % and 31.60 %. The corresponding minimum indicated specific fuel consumption under the two power output modes are 211.7 g/kW∙h and 243.7 g/kW∙h, respectively, accompanied by NOx emission factors of 25.3 g/kW∙h and 17.6 g/kW∙h. With the given range of ignition timing, a trade-off relationship exists between the engine performance and NOx emissions. The power density of the case of power output by Shaft 3 is superior to that of Shaft 1.

Comparative Analysis of Hybrid Maximum Power Point Tracking Algorithms Using Voltage Scanning and Perturb and Observe Methods for Photovoltaic Systems under Partial Shading Conditions

Partial shading significantly affects the performance of photovoltaic (PV) power systems, rendering traditional maximum power point tracking (MPPT) methods ineffective. This study proposes a novel hybrid MPPT algorithm integrating voltage scanning and modified Perturb and Observe (P&O) techniques to overcome the limitations posed by partial shading. This algorithm has a simple structure and does not require panel information such as the number of panels or voltage due to its voltage scanning feature. To test the proposed algorithm, a grid-connected PV power system with a power of 252.6 kW was created in the MATLAB/Simulink environment. In this power system, six different PS conditions, containing quite challenging situations, were listed in three different scenarios and simulated. The proposed algorithm was compared with the voltage scanning and P&O and voltage scanning and variable-step P&O methods. It was observed that the proposed algorithm has lower power fluctuations compared to the other two traditional methods. Additionally, this algorithm managed to achieve higher efficiency than the other methods in some cases.

Terrestrial locomotion characteristics of climbing perch (Anabas testudineus).

The evolution and utilization of limbs facilitated earlier terrestrial vertebrate movement on land, but little is known about how other lateral structures enhance terrestrial locomotion in amphibian fishes without terrestrialized limb structures. Climbing perch (Anabas testudineus) exhibit sustained terrestrial locomotion using uniaxial rotating gill covers instead of appendages. To investigate the role of such simple lateral structures in terrestrial locomotion and the motion generating mechanism of the corresponding locomotor structure configuration (gill covers and body undulation), we measured the terrestrial kinematics of climbing perch and quantitatively analysed its motion characteristics. Here, the digitalized locomotor kinematics show a unique body postural adjustment ability that enables the regulation of the posture of the caudal peduncle for converting lateral bending force into propulsion. An analysis of the coordination characteristics demonstrated that the motion of the gill cover is kinematically independent of axial undulation, suggesting that the gill cover functions as an anchored simple support pole while axial undulation actively mediates body posture and produces propulsive force. The two identified feature-shapes explained more than 87% of the complex lateral undulation in multistage locomotion. The kinematic characteristics enhance our understanding of the underlying coordinating mechanism corresponding to locomotor configurations. Our work provides quantitative insight into the terrestrial locomotor adaptation of climbing perch and sheds light on terrestrial motion potential of locomotor configurations containing a typical aquatic body and restricted lateral structure.

WRITING PRINCIPLES OF BUSINESS CORRESPONDENCE

A business correspondence is a written communication between two parties in a trade. During business correspondence exchanges, both parties’ points of view, as well as ideas and information must be communicated. An efficient exchange of business correspondence can assist domestic manufacturers and foreign customers in establishing or maintaining long-term friendly relationships. It is undeniably critical to learn how to write effective business letters. The present article focuses on the characteristics of the language used in business correspondence, specifically, its lexical and structural characteristics. The analysis shows that the key to establishing successful business communication lies in using concise language, simple structure and unitary contents.

Ultra-high sensitive dual-parameter sensor based on double-hole fiber for simultaneous detection of magnetic field and temperature

An ultra-high sensitive dual-parameter sensor based on double-hole fiber (DHF) is proposed for simultaneous detection of magnetic fields and temperatures. The sensor utilizes the DHF containing a Ge-doped core with two large air holes symmetrically arranged at its two sides. To enhance the sensitivity to both a magnetic field and temperature, Al wires with different diameters are embedded on the inner walls of the air holes in the DHF, creating a magnetic field sensing channel filled with magnetic fluid and a temperature sensing channel filled with thermo-sensitive liquid. Structural parameters and metal materials of the sensor are optimized by using the finite element method. Numerical results demonstrate that this DHF-based dual-parameter sensor can detect magnetic fields ranging from 40 Oe to 130 Oe and temperatures ranging from 24.3 °C to 49.3 °C simultaneously. The maximum magnetic field sensitivity reaches up to 64000 pm/mT, while the maximum temperature sensitivity is approximately 44.6 nm/°C, both exceeding current reports by more than one order of magnitude for simultaneous detection of magnetic field and temperature. With its high sensitivity, low fabrication difficulty, and simple structure, this DHF-based dual-parameter sensor has potential applications in the fields of material characterization analysis, geological environmental monitoring, and aeronautical engineering.

A Reconfigurable Bipolar Image Sensor for High-Efficiency Dynamic Vision Recognition.

Dynamic vision perception and processing (DVPP) is in high demand by booming edge artificial intelligence. However, existing imaging systems suffer from low efficiency or low compatibility with advanced machine vision techniques. Here, we propose a reconfigurable bipolar image sensor (RBIS) for in-sensor DVPP based on a two-dimensional WSe2/GeSe heterostructure device. Owing to the gate-tunable and reversible built-in electric field, its photoresponse shows bipolarity as being positive or negative. High-efficiency DVPP incorporating front-end RBIS and back-end CNN is then demonstrated. It shows a high recognition accuracy of over 94.9% on the derived DVS128 data set and requires much fewer neural network parameters than that without RBIS. Moreover, we demonstrate an optimized device with a vertically stacked structure and a stable nonvolatile bipolarity, which enables more efficient DVPP hardware. Our work demonstrates the potential of fabricating DVPP devices with a simple structure, high efficiency, and outputs compatible with advanced algorithms.

Effects of natural Ionones and derived novel analogues with simplified structures on behavioral responses of whiteflies.

Whiteflies are major pests in agriculture, causing damage to crops and transmitting plant viruses. Using Volatile Organic Compounds (VOCs) as semiochemicals offers a sustainable approach for combating whiteflies. One such group of compounds, represented by β-ionone, has been found to possess repellent/attractant properties. To further explore the behavioral effects of these compounds on whiteflies, we selected five natural ionone compounds and synthesized six novel analogues to examine the impact of structural variations on whitefly behavior. Our results demonstrated that β-ionone and its analogues have a significant impact on the behavior of whiteflies. Among them, 0.01% pseudo ionone solution exhibited an attractant effect on whiteflies. Notably, the application of 1% β-ionone and 0.1% β-ionol solution demonstrated a notable repellent effect and oviposition deterrent effect on whitefly. We also found that the novel ionone analogue (±)1A exhibited a strong repellent effect. Both β-ionol and compound (±)1A possess high logP values and low saturation vapor pressures, which contribute to enhanced lipophilicity, making them more likely to penetrate insect antennae and prolong their presence in the air. The newly discovered ionone analogue (±)1A and β-ionol exhibit improved repellent effects, while pseudo ionone shows an attractant effect. These three compounds hold promising potential for development as novel biological control agents. Our work highlights the efficacy of VOCs as a protection method against whiteflies. These findings indicate that our new technology for a 'push-pull' control method of B. tabaci can offer a novel tool for integrated pest management (IPM). © 2024 Society of Chemical Industry.

A super-compact wideband bandpass filter using capacitor-loaded coupled lines

Abstract A wideband bandpass filter (BPF) using capacitor-loaded coupled lines is proposed with super-compact circuit size and very simple structure. By loading three lumped capacitors in parallel to three same pairs of coupled lines, three transmission poles and four transmission zeros can be achieved and they can be calculated by input admittance derivation. To verify the design, a wideband BPF prototype with center frequency at 1.34 GHz is fabricated, whose measured 3-dB fractional bandwidth is 98.5 % (0.68–2 GHz), in-band insertion loss is less than 0.5 dB, return loss is greater than 17.5 dB, and circuit size is only 0.24 λ g × 0.02 λ g (λ g: guided wavelength at the center frequency).