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关键词： photovoltaic system   MPPT   IMSPO-SFLA   MATLAB  

摘要： To enhance the power generation efficiency of the photovoltaic system, it is necessary to ensure that it can operate stably at the global maximum power point (MPP). This paper presents a study on the maximum power point tracking(MPPT) technology of photovoltaic system and a new MPPT technique based on the improved multi-subgroup parallel optimization algorithm with shuffled frog leaping algorithm (IMSPO-SFLA) is proposed, which combines the improved multi-subgroup parallel optimization algorithm with the shuffled frog leaping algorithm. Moreover, the developed MPPT technique improves the tracking accuracy of the MPP, increased the speed of MPP tracking, the problem of the traditional frog leaping algorithm being prone to falling into a local optimum is successfully overcame by it. In order to verify the effectiveness of the method, a simulation model is established in MATLAB in this paper. The Simulation results show that the method proposed in this paper can make the photovoltaic power generation system be operated more efficiently, which contributes to the development of the renewable energy field and promotes the progress of clean energy technology. Compared with the traditional algorithm, it has obvious advantages in realizing the MPPT of PV power generation system. (c) 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

关键词： MATLAB  

摘要： To explore the pore characteristics and uniaxial compression mechanical properties of basalt fiber reinforced foam concrete (BFRFC) with varied densities and fiber mixtures, this study carries out X-ray computed tomography (X-CT) and uniaxial compression tests on samples featuring three types of fiber mixtures at two different densities. It examines the pore and fiber distribution within these samples and leverages Matlab to develop a three-dimensional reconstruction model of BFRFC's microstructure. Additionally, a progressive damage model, grounded in Hashin's failure criteria and damage variables, has been formulated. The uniaxial compression test simulations were executed using Comsol's finite element software. The findings indicate that BFRFC's pore diameter follows a lognormal distribution. Notably, both porosity and average pore diameter exhibit a decrease with increasing density and fibre content;Within BFRFC, the polar angle of the fibers predominantly ranges from 15° to 90°, whereas the azimuthal angle is uniformly distributed across 0° to 360°. The microstructure-based simulation model of BFRFC, integrated with the progressive damage model that accounts for the material's softening characteristics, proves effective in simulating the material's progressive damage. Furthermore, the microstructure-based simulation model, when coupled with the progressive damage model that considers the softening traits of the material, accurately simulates the uniaxial compression behavior of BFRFC. The incorporation of basalt fibers into BFRFC notably enhances its mechanical properties, such as peak strength and energy absorption capacity. Moreover, during the uniaxial compression process, the material's mechanical response is progressively relayed from the outer to the inner layers, enhancing its structural integrity and resilience. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： indirect PVT   simulink   integration   heat storage  

摘要： In this paper, an original numerical investigation of indirect parallel photovoltaic/thermal system integration using Matlab/Simulink is carried out. The added value is to evaluate the potential use of integrated PVT (Photovoltaic-Thermal) solar systems in residential applications and the possibility of controlling and investigating their performance to optimize the results under weather conditions throughout the year. A substantial number of annual simulations have been conducted to encompass the best performance using each control, with an emphasis on two configurations of cooling approaches. Results show that an optimal mass flow rate of about 0.0125 kg/s for both collector and storage tank pumps was found. For the direct cooling method, results reveal an increase in overall system efficiency of the order of 41.4%. In addition, the paper compares the PVT system with a stand-alone PVT collector, and the results indicate that integrated PVT leads to a relative improvement in electrical and thermal efficiency of about 7.89% and 24.62%, respectively.

关键词： artificial intelligence   neural networks   MATLAB   inverse problems   heat conduction  

摘要： In recent years, significant progress has been made in the development and application of artificial intelligence, spanning various fields and presenting powerful potential applications. The investigation of how to integrate the achievements of artificial intelligence with traditional physical problems has become a crucial task. Neural networks are considered as a pivotal technology of artificial intelligence, showcasing their distinctive ability to comprehend intricate nonlinear relationships through simulation and learning, and has showed exceptional performance in handling large-scale data and addressing inverse problems. This article begins by introducing the fundamental principles of neural networks, providing a detailed explanation of the process involved in constructing classical neural networks. A neural network was constructed on the MATLAB platform, and the practical application process was illustrated through lively demonstrations using simple examples. Tailored primarily for physics education, this article is designed to be suitable for undergraduate-level educational purposes. Through the integration of neural networks with practical inverse heat conduction problem, we not only provide a more interactive and dynamic learning experience but also enrich undergraduate students' comprehension and interest in relevant issues within higher education. This integrated teaching approach has the potential to propel interdisciplinary collaboration, nurturing innovation and advancement within the field of physics education.

关键词： 射流扩散火焰   空气侧掺混   推举速度   吹熄速度   烟气排放  

摘要： 工业挥发性有机物(volatile organic compounds,VOCs)废气处理是燃料清洁高效利用的重要研究方向之一.以丙烷作为VOCs代表,研究了空气伴流和空气侧掺混不同含量丙烷(体积分数分别为 0.5%,1%,1.5%,2%)对火焰形态和稳定性的影响.结果表明:随着伴流速度增大,火焰提前发生推举和吹熄行为;随着空气侧掺混丙烷含量增加,火焰的初始推举速度和临界吹熄速度增大,火焰稳定性增强,推举火焰对应的雷诺数(Re)范围减小.根据预混理论分析了掺混丙烷后火焰稳定性提高的原因.固定伴流速度和射流速度条件下,掺混丙烷后导致湍流火焰传播速度增加,达到平衡对应的局部气速增大.分析空气伴流和空气侧掺混体积分数分别为1%和2%丙烷时烟气排放,发现相同射流Re下,随着丙烷掺混量增大,CO排放量增加,燃烧更不充分.丙烷掺混量高时,湍流阶段CO2 排放量稍降低.空气伴流下NOx排放量高于掺混丙烷下NOx排放量,主要原因是掺混丙烷后反应面的氮气量减少,NOx相应减少.

关键词： 冠心病   三支病变   不稳定性心绞痛   血小板减少症   麝香保心丸  

摘要： 目的 探讨严重冠心病不稳定性心绞痛伴血小板减少症不能够应用抗栓及介入治疗,而应用麝香保心丸的治疗效果.方法 应用麝香保心丸对一例严重冠心病不稳定性心绞痛伴血小板减少症患者进行治疗.结果 麝香保心丸明显改善该患者心肌缺血及症状,改善其预后.结论 对严重冠心病不稳定性心绞痛伴血小板减少症不能应用抗栓及介入治疗,可以应用麝香保心丸,可明显改善患者心肌缺血及症状,对预后有积极作用.

关键词： 建筑工程造价   预结算   审核工作要领   管理标准  

摘要： 近年来,随着社会经济稳步发展,逐渐增加了我国建筑建设规模与数量.在这种环境背景影响下,显著提高了预结算审核难度,由于预结算审核工作范围比较广,所涉及到的内容比较复杂,进行审核时一旦产生问题,会对建筑工程综合效益的提升造成干扰.以此为基础,本文将深入剖析预算审核工作要领与管理标准,旨在为预结算审核工作质量的提升奠定基础.