Parallel Connection Research Articles

基于改进注意力机制的番茄叶部病害检测方法研究

The precise detection and recognition are the premise in accurate prevention and control of tomato diseases. To improve the accuracy of tomato diseases recognition model, nine kinds of sick leaves images including tomato target spot bacteria in Plant Village and healthy leaves images were used. A new attention mechanism module called CBAM-Ⅱ was created by changing the serial connection between Channel and Spatial attentions of CBAM to parallel connection, and then the results of two modules were added together. CBAM-Ⅱ had been verified to be effective and universal in the convolutional neural network model. The accuracy of MobileNet-V2 with CBAM-Ⅱ model was 99.47%，which had increased by 1.13%, 0.93%, 0.7%8 and 1.06 % respectively comparing with MobileNet-V2 model, MobileNet-V2 plus Channel attention module, MobileNet-V2 plus Spatial attention module, and CBAM attention module. Furthermore, the accuracy of AlexNet, Inception-V3 and ResNet50 model has increased 1.73, 0.15 and 0.33 % respectively when the CBAM-Ⅱ module was added. Results showed that the proposed module CBAM-Ⅱ created in this experiment is more effective in MobileNet-V2 model for tomato diseases recognition, and could solve interference problems resulted from the serial connection. Additionally, the accuracy of four convolutional neural network models including Mobilenet-V2, AlexNet, Inception-V3 and ResNet50 model had all increased when the CBAM-Ⅱ module was added, which represented the good universality of CBAM-Ⅱ module. The results could provide technical support in accurate detection and control of tomato diseases.

Topographic organization in the cerebellar nuclei and inferior olive in relation to cerebellar hemispheric lobules in the mouse: Distinction between crus I and neighboring lobules.

The parallel closed-loop topographic connections between subareas of the inferior olive (IO), cerebellar cortex, and cerebellar nuclei (CN) define the fundamental modular organization of the cerebellum. The cortical modules or zones are organized into longitudinal zebrin stripes which are extended across transverse cerebellar lobules. However, how cerebellar lobules, which are related to the cerebellar functional localization, are incorporated into the olivo-cortico-nuclear topographic organization has not been fully clarified. In the present study, we analyzed the lobular topography in the CN and IO by making 57 small bidirectional tracer injections in the lateral zebrin-positive stripes equivalent with C2, D1, and D2 zones in every hemispheric lobule in zebrin stripe-visualized mice. C2, D1, and D2 zones were connected to the lateral part of the posterior interpositus nucleus (lPIN), and caudal and rostral parts of the lateral nucleus (cLN, rLN), respectively, and from the rostral part of the medial accessory olive (rMAO), and ventral and dorsal lamellas of the PO (vPO, dPO), respectively, as reported. Within these areas, crus I was specifically connected to the ventral parts of the lPIN, cLN, and rLN, and from the rostrolateral part of the rMAO and the lateral parts of the vPO and dPO. The results indicated that the cerebellar modules have lobule-related subdivisions and that crus I is topographically distinct from other lobules. We speculate that crus I and crus I-connected subdivisions in the CN and IO are involved more in nonmotor functions than other neighboring areas in the mouse.

Heating Performance and Economic Analysis of Solar-Assisted Cold-Water Phase-Change-Energy Heat Pump System in Series and Parallel Connections

To study the heating performance of a solar-assisted cold-water phase-change-energy heat pump system, its heating performance under series and parallel connections is simulated for a community in Harbin, the influence of ice thickness on the different operation modes is analyzed, and the economy of the system is calculated for series and parallel connections in this paper. The results show that the water supply temperature is higher and more uniform in the parallel operation, and more terminal heat is supplied; the ice thickness has more of an influence on the series connection compared to the parallel connection; and the dynamic payback period is 6.72 years for the series connection and 7.28 years for the parallel connection. This case study can serve as a guide for practical engineering application projects and act as a reference for heating and economic data for the promotion of this heat pump system.

AMFF-Net: An attention-based multi-scale feature fusion network for allergic pollen detection

Automatic pollen detection based on light microscope (LM) images is helpful for pollinosis symptoms prevention. Recently, many deep learning methods have been proposed to identify pollen grains based on multi-scale feature fusion mechanism. However, in real scenarios, there are two main challenges that need to be considered: (1) Complex pollen characteristics; (2) Irrelevant objects interference. It means that the pollen detection requires not only learning the relationship among multi-scale features but also refining the feature representation. To this end, this paper proposes an attention-based multi-scale feature fusion network (AMFF-Net) for automatic pollen detection on real-world LM images. The proposed AMFF-Net includes three modules: The feature extraction module utilizes the series-connection attention to capture the spatial and channel dependencies of different level feature maps (for solving the challenge 1). In the feature fusion module, a parallel connection attention is able to learn more discriminative feature representation based on bidirectional pathway guidance (for solving the challenge 2). Both are jointly adopted to enhance the representational capacity of the final results in the pollen prediction module. Extensive experiments are conducted on the real-world RPD dataset, and our AMFF-Net achieves the best performance (83.9% of mean average precision) comparing with other state-of-the-art methods. We believe that this work can serve as an important reference for the development of pollen monitoring system in a real scenario.

Performance evaluation of three constructed wetland-microbial fuel cell systems: wastewater treatment efficiency and electricity generation potential.

Constructed wetlands (CWs) have proven to be effective and environmentally friendly for removing pollutants, while microbial fuel cells (MFCs) offer the potential for electricity generation. Thus, this study evaluated the performance of three CW-MFC systems (zigzag, single-column, and triple-column continuous) for domestic wastewater treatment and electricity generation. Results showed that parallel connection of CW-MFCs significantly improved power generation compared to series connection. Additionally, using three copper wires to connect carbon fiber felt electrodes demonstrated superior pollutant capture capabilities compared to a single copper wire. During the 14-day testing period, the single-column system achieved the highest power density of 5.55 mW m-2, followed closely by the triple-column continuous system at 4.77 mW m-2. In contrast, the zigzag system exhibited a lower power density of 2.49 mW m-2. Interestingly, the implementation of facultative anaerobic conditions in the anode, along with the application of a plastic bag cover, facilitated the maintenance of anaerobic conditions in both the single-column and triple-column continuous systems. This resulted in increased power density and reduced internal resistance. In contrast, the zigzag system, with its larger surface area, aeration, and circulation, exhibited higher internal resistance and lower current dissipation. Despite its inferior electricity generation performance, the zigzag system demonstrated higher efficiency removal of chemical oxygen demand (COD), nitrate (NO3-), and phosphate (PO43-) than the single-column system. This can be attributed to the extended contact time, resulting in enhanced pollutant removal. Overall, the multi-column continuous system shows promise as a viable approach for simultaneous domestic wastewater treatment and electricity production, offering potential benefits for sustainable wastewater management.

Experimental Investigation on the Flow Boiling of Two Microchannel Heat Sinks Connected in Parallel and Series for Cooling of Multiple Heat Sources.

Cooling methods for multiple heat sources with high heat flux have rarely been reported, but such situations threaten the stable operation of electronic devices. Therefore, in this paper, the use of two microchannel heat sinks is proposed, with and without grooves, labeled Type A and Type B, respectively. Experimental investigations on the flow boiling of two microchannel heat sinks connected in parallel and in series are carried out under different mass fluxes. In addition, a high-speed camera is used to observe flow patterns in the microchannels. The cold plate wall temperature (Tw), heat transfer coefficient (HTC), and pressure drop (PD) are obtained with the use of two microchannel heat sinks. The flow patterns of the bubbly flow and elongated bubbles in the microchannels are observed. The results of the analysis indicated that the Tw, HTC, and PD of the two microchannel heat sinks connected in parallel were degraded, especially when using the Type A-B parallel connection. Compared to the use of a single heat sink, the maximum decrease in HTC was 9.44 kW/(m2K) for Type A heat sinks connected in parallel, which represents a decrease of 45.95%. The influence of the series connection on the Tw, HTC, and PD of the two heat sinks is obvious. The Type A-A series connection exerted the greatest positive effect on the performance of the two heat sinks, especially in the case of the postposition heat sink. The maximum increase in HTC was 12.77 kW/(m2K) for the postposition Type A heat sink, representing an increase of 72.88%. These results could provide a reference for a two-phase flow-cooling complex for multiple heat sources with high heat flux.

Sodium alginate based energy harvesting fibers: Multiscale structure and moist-electrical properties

Moist-electric generation, a new energy harvesting technology, exhibits unique advantages in sustainable energy collection and compatibility with environment. However, the lack of research on fiber based moist-electric generation materials and multiscale structure-moist electric performance relationship has restrained the extensive development and application of this energy generation method. In this work, sodium alginate (SA)/multi-walled carbon nanotubes (MWCNT) coaxial fibers with radial gradient difference of oxygen-functional group are prepared through wet spinning. Meanwhile, the aggregate structures of SA/MWCNT fibers are regulated by adjusting the spinning and post-drawing process. The relation between moist electric generation performance and multiscale structure of SA/MWCNT fibers, including the effect of oxygenated group distribution and crystalline structure, are investigated for the clarification of moist-electric mechanism. Based on structure design, the coaxial fiber moist-electric generator (CFMEG) shows excellent moist-electric properties, continuous output ability, and environmental adaptability. The maximum output power density of CFMEG with a length of only 1 cm can reach 3.09 ∼ 9.50 μW/cm2 at RH = 90 ∼ 95% from an extreme voltage of 0.35 ∼ 0.38 V and current of 1.64 ∼ 1.74 μA, which exceeds most of the same type of moist-electric research. A long-last output voltage of 0.15 V for more than 36 h can be obtained from this CFMEG, which is able to generate an output voltage of 1.0 to 6.9 V after series and parallel connection to illuminate LEDs directly without additional capacitors. The CFMEG from multiscale structure design provides a way of preparation of flexible power supply devices using green resource with low density and exhibits great opportunity for common purpose application.

DC Fault Current Limiting Characteristics of Flux-Lock Type SFCL With Parallel Connection of Two Coils Using Twice Quench

In this paper, DC fault current limiting characteristics of DC flux-lock type superconducting fault current limiter (SFCL) with parallel connection between two coils were analyzed. DC flux-lock type SFCL with parallel connection between two coils was composed of two windings connected in parallel and two superconducting modules (SMs), which were connected in series with each secondary winding. DC flux-lock type SFCLs with a parallel connection between two coils and one SM with one secondary winding in series was thought to perform fault current limiting operation as in AC system. However, since the transient period after resistance generation in SM approaches into the constant value, unlike the AC system, there is a DC current limiting transient period. Therefore, the DC current limiting effect disappears in the DC system and the recovery characteristic after the fault is removed also disappears. To analyze the DC fault current limiting and recovery characteristics, a DC short-circuit test was per-formed, and the various behaviors of flux-lock type SFCLs in DC systems were investigated from the test results.

Design and evaluation of a magnetically coupled piezoelectric energy harvester with parallel connection.

This work proposed a magnetically coupled piezoelectric energy harvester with parallel connections. The rectangular piezoelectric patch in the upper part of the device generates regular vibrations due to the nonlinear forces caused by magnetic coupling. The lower rectangular piezoelectric patch is deformed by contact collision excitation. The parallel connection effectively connects the two sets of piezoelectric patches together and fully exploits the performance of the piezoelectric energy harvester. The intrinsic frequency of the rectangular piezoelectric patch was simulated and verified experimentally. The rectangular piezoelectric patch generates a large vibration amplitude in high-speed operation due to its elasticity property. From the experimental results, it can be seen that the piezoelectric energy harvester can work well in different frequency bands. The parallel piezoelectric energy harvester with a three-contact rotor has a peak-to-peak voltage of 252V at a speed of 120 r/min and 200V at a speed of 240 r/min. The maximum voltage achieved by the piezoelectric energy harvester in parallel is 266V at a speed of 180 r/min with a resistance of 1000 kΩ. The maximum voltage reached by a series-connected piezoelectric energy harvester is 256V at a speed of 180 r/min and a resistance of 100 kΩ. The peak-to-peak power of the piezoelectric energy harvester connected in parallel is 0.313W under a resistance of 100 kΩ and a speed of 180 r/min. Besides, the developed piezoelectric energy harvester can light up to 60 light-emitting diodes. Accordingly, the energy can be effectively harvested by the piezoelectric energy harvester and then supplied to the microelectronic device.

Investigating thermal runaway characteristics and trigger mechanism of the parallel lithium-ion battery

Thermal runaway is considered the main cause resulting in fire and explosions of energy systems containing lithium-ion batteries. This study presents a fundamental understanding of quantifying thermal runaway characteristics of the parallel battery and revealing the corresponding trigger mechanism by eliminating the thermal interactions between batteries. The influence of connection mode, number of batteries in parallel and connector thickness on thermal runaway triggering are concerned herein. The parallel connection can cause the thermal runaway to be triggered prematurely but has little influence on the thermal runaway characteristics. The transferred electricity between batteries is responsible for the premature trigger of thermal runaway in the parallel battery, whose value accounting for 4.6% of the battery capacity is sufficient to advance thermal runaway to the open time of the safety valve. Due to the joule heat resulting from the transfer of electricity, the local thermal runaway of the parallel battery occurs first in the upper zone near the electrode tabs, then propagates to the whole battery. Moreover, a mathematical model of the thermal runaway triggering in the battery in open circuit is proposed, and the dominant influence mechanisms of transferred electrical energy on the occurrence of thermal runaway in the parallel battery are developed.

Design and simulation study on the heating performance of mesh heating elements

AbstractTo achieve uniform heating of heat‐not‐burn cigarettes, the ANSYS Workbench was used to verify the calculation rule of the resistance value of the mesh heating element. To provide a theoretical basis for improving the design of mesh heating elements, the effect of rounded corners on the resistance value and that of key parameters such as the number of mesh heat emitters in series and parallel, mesh density, and heating power on the heating uniformity were investigated. The deviation of all calculation results is less than 2.4%, indicating that the total resistance value of the mesh heating element conforms to the calculation rule of the series and parallel connections of single‐module resistors. The heating power increases by 3.2%, which has a relatively small impact on the overall heating element when a rounded corner with a radius equal to the line width is added to the corner of the heating element. The area of the heating body increases when increasing the number of series connections and reducing the number of parallel connections, which is conducive to uniform heating. While maintaining the ratio of the number of series connections to the number of parallel connections constant, reducing the module size will not change the area of the mesh heating element, but it will improve the temperature uniformity. Under different power conditions, the heating uniformity of the same heating element does not change.

A Scalable Electronic-Embedded Transformer, a New Concept Toward Ultra-High-Frequency High-Power Transformer in DC–DC Converters

The demand for high-power and high-density isolated dc-dc converter is driven by the rapid development of energy storage system, data center power supplies and transportation electrification. However, designing a high-power and high-frequency transformer presents significant challenges due to the trade-off between thermal management, leakage inductance minimization, and insulation requirements. In order to overcome this trade-off between power rating and operation frequency, a scalable electronic-embedded transformer (EET) is proposed with a low voltage bridge integrated into the transformer windings. The EET addresses the challenge through its simple open-loop control and natural current sharing, enabling easy parallel connection and scaling to different power ratings. Based on this concept, a bi-directional EET-based dc transformer (EET-DCX) is proposed to solve the transformer-level paralleling and resonant point shift issues in traditional LLC-DCX designs. By employing the embedded full bridge, the EET-DCX effectively cancels out the impedance of the leakage inductance, ensuring optimal operation at any frequency. Additionally, the EET-DCX retains the inherent advantages of the LLC-DCX, such as load-independent voltage gain, simple open-loop control, full load range zero voltage switching (ZVS), and low circulating current. Leveraging these advantages, the proposed EET-DCX solution has the potential to push the boundaries of transformer performance to the MHz operation frequency range with hundreds of kilowatts power capability. To validate these merits, a 12 kW 500 kHz EET-DCX with four planar EET units was built. This article is accompanied by two videos demonstrating the dynamic load changing and frequency changing test.

Power Supply for Superconducting Magnets

The self-heating caused by the heat entering through the current supply conductor from the outside to the inside of the cryostat and by the energizing current in the power supply unit of the high-temperature superconducting coil magnet (hereafter referred to as HTS magnet) causes an increase in the cooling load of the cryocooler. As a countermeasure, a technique was devised to increase the superposition of the incoming current on HTS magnet current by multiple control of the time-division drive of a multi-parallel chopper installation inside the cryostat in order to reduce the energizing current of the conductors. The circuit simulation results confirmed that the circuit is valid for stable increase of magnet current up to the target value, including at startup, and for low ripple current values. In addition, the size of the main circuit board for magnet current 300A was also confirmed by a schematic design in combination with the short circuit of the HTS magnet using a parallel connection of low ON resistance MOSFETs. Excitation power supply for HTS magnet under study is intended for use with high-temperature superconducting non-insulated (NI) coil, but it may also be used for metallic superconducting magnets.

Evaluation of front and backside performances of a large surface organic photovoltaic module under bifacial illumination

Semitransparency is one of the attractive characteristics of thin-film solar modules as it allows electricity generation while providing building illumination. However, enhancing transparency can result in lower energy generation efficiency. An effective way to improve energy production in semitransparent modules is through bifacial illumination. This work aims to evaluate, experimentally, and discuss the optical and electrical properties of a commercial, semitransparent organic photovoltaic (OPV) module under bifacial illumination. With that purpose, current-voltage characteristic curves were obtained under the following conditions: a) front, b) rear illumination and c) simultaneous illumination on both faces. The module was placed inside a V-trough cavity to implement electrical measurements with the module's both faces simultaneously illuminated by natural sunlight. Results show that bifacial illumination is an effective way to enhance energy production in semitransparent OPV devices, and a 46% increase in power generation compared to traditional illumination (frontal illumination) was achieved in the experiments. The backside illumination performance differs by over 40%, compared with the front side, due to electrode shading, optics, and differences in the energy conversion processes taking place in the active layer. The OPV module operation under bifacial illumination is equivalent to a parallel connection between the front and backside illumination performances. Optical modeling shows that the active layer absorbs a large part of the incoming light within the cell spectral response. Nevertheless, in the case of frontal illumination, a significant fraction of solar radiation in the visible region is transmitted and remains available, for instance, for building illumination purposes.

A Novel Pulse Compression Diode for Picosecond Pulse Generation

A novel pulse compression diode capable of generating high-voltage, picosecond pulses is introduced. The design concept and technical means of the novel diode based on semi-insulating gallium arsenide (SI-GaAs) materials are described, followed by the presentation of its static characteristics with three unique operating states. Typical output rise time for the novel diode with self-breakdown is limited to a few nanoseconds (1–2 ns). The basic physical mechanism affecting the fast conduction of the device is then analyzed, and the electrode structure is optimized as a consequence. Finally, a test circuit with a MOSFET as a preswitch is used as an example to verify the compression characteristics of the modified device. The experimental results show that the pulse front is sharpened from 32 ns to 853 ps and the full-width at half-maximum (FWHM) is sharpened from 120 to 2.1 ns by the pulse compression diode without extra triggering. Lifetime measurement experiments were conducted at a pulse repetition frequency of 100 Hz, revealing no instances of switch failures or malfunctions. The novel pulse compression diode has great potential for various applications, including in national defense, industrial, and medical sectors, due to its fast response, long lifetime, high reliability, and ease of series–parallel connection.

Parallel Connection of Silicon Carbide MOSFETs—Challenges, Mechanism, and Solutions

Parallel Connection of Silicon Carbide MOSFETs—Challenges, Mechanism, and Solutions

Flood Retention Lakes in a Rural‐Urban Catchment: Climate‐Dominated and Configuration‐Affected Performances

AbstractFlood retention lakes (RLs) are widely employed in rural‐urban catchments with low impacts on the natural environment. However, insights are lacking regarding the control of climate conditions on RLs' performances and how they are affected by different geographic configurations. This study applies a 2D hydrodynamic model to perform a catchment‐scale performance assessment of RLs beyond the scope of analytical and hydrological models. We conduct extensive numerical experiments of rainstorm‐induced flooding in a rural‐urban catchment with a constructed RL and blueprinted ones upstream. Results demonstrate an L‐shaped band of satisfactory performance of the current RL in the frequency‐duration diagram, which coincides with short return periods (<5 years) and long durations (>4 hr), or short durations (<3 hr) and moderate to long return periods (5–50 years); such L‐shaped pattern is also valid for additional RLs and their combinations. With the increase in event size, the first two modes of RL performance (out of four) correspond to effective flood mitigation. When working jointly, RLs with series configurations are more effective in reducing the mainstream flood peaks, while parallel connections provide a greater spatial extent of flood hazard mitigation. For both series and parallel configurations, the upstream‐weighted settings tend to outperform downstream‐weighted ones under more extreme events; the decentralized arrangement in the urban area yields more benefits in spatial flood hazard mitigation compared to the centralized case. The study highlights the critical role of rainstorm severity (with possible spatiotemporal variabilities) in controlling RL performances despite various configurations and hydraulic settings.

Artificial Intelligence Approach for the Control of SPMSG Based Grid Connected WECS

In India, power plant requirement is rapidly increasing as non-conventional sources are in current need. Government financial aid plays important role for generator plant execution because of its tedious procedure. If the utilization of wind power production has to be doubled, then machines, turbines and converters are essential in two numbers. The research work includes parallel connection of two machines using star-delta-star transformer fashion resulting in six-phase permanent synchronous machine. This arrangement is more economical as the number of converters are reduced thereby increasing the efficiency by minimizing the switching losses. Initially rectifier setup is used wherein high frequency AC is converted to low frequency and maximum power point tracking is done with the aid of a converter. It is DC-DC conversion by decoupled DQ strategy. Later, it is again converted back to three phase AC so as to synchronize it to the grid. The system response is analysed by conventional PI controller by reducing the noise in the real & reactive power generation. Further, ANFIS-PI controller is implemented to improve the response of PI controller which is much essential for wind power generation. The MATLAB simulated results of PI controller system response and ANFIS-PI controller is presented in this paper.

A Study of Directional Patterns of Ultrasonic Parametric Array

The paper presents results of numerical calculations and experimental data on the directional pattern of two 38-element parametric arrays composed of ultrasound sources. Two types of antenna arrays are considered, namely with parallel and coaxial connections of ultrasonic transducers (elements). The results of selecting and functional testing of unit elements are described in this paper. It is found that in the coaxial element connection of the antenna array, the level of side lobes is higher than that in the parallel element connection.

Pelaksanaan Perjanjian Jual Beli Tenaga Listrik Antara PT. PLN (Persero) dengan Pelanggan Rumah Tangga di Kecamatan Pangkalan Kerinci Kabupaten Pelawawan

The need for electrical energy is the lifeblood of human life; in that case, if you want electricity, you must use the services of PT. PLN (Persero) with the terms and conditions of the agreement between the customer and PT. PLN (Persero). Public relations, both people and PT. PLNs, which are in a position called customers, were born on a bond of agreement. However, several problems occurred between the customer and PT. PLN regarding the agreement that needed to be carried out correctly. The formulation of the problem in this study is how the implementation of the power purchase agreement between PT. PLN (Persero) with household customers in Pangkalan Kerinci District, Pelalawan Regency, and what factors cause obstacles in the power purchase agreement in Pangkalan Kerinci District, Pelalawan Regency. The research method is a sociological, legal research method, namely legal research that wants to see the correlation of people's opinions as customers of PT. PLN (Persero) related to the electricity purchase agreement letter between the community as customers of household needs. The study results show that implementing these rights and obligations and the things agreed upon by the parties in a large percentage can be carried out. And the inhibiting factors are delays in electricity payments with complete or temporary disconnections, pole planting, and parallel connections.