Unit commitment considering generator outages through a mixed-integer particle swarm optimization algorithm

The optimum economic operation and planning of electric power generation systems occupies a crucial position in the electric power industry. Unit commitment (UC) is an important function in generation resource management. Moreover, it is nowadays critical to incorporate reliability analysis of the power system into its design of operation strategy. For this purpose, equipment malfunction or failure should be considered in unit commitment. In this paper, first the model for UC considering generator outages is formulated, where the reliability requirement is incorporated into the spinning reserve constraint in the optimization design. Then, a mixed binary- and real-coded particle swarm optimization (PSO) is developed to locate the optimum generation combination. A 10-generator test power system is used to verify the effectiveness of the proposed approach along the 24-h planning horizon. A comparative study is conducted to examine the impact of reliability constraint on the optimal solution obtained. Furthermore, comparison is made between the proposed method and other methods including both analytical and meta-heuristic algorithms.     

基于ROI多特征和相关反馈的图像检索算法

本文提出了一种基于感兴趣区域(ROI)综合多特征和相关反馈的图像检索算法.在对图像进行四叉树分解的基础上,由用户选择感兴趣区域,综合颜色、纹理和形状三种底层特征进行多层感兴趣区域检索;由相关反馈技术体现用户感知的主观性,通过调整感兴趣区域、特征问、特征内的权重来提高查准率.给出了改进的CBIR通用模型和特征权重模型.实现了一个图像检索原型系统,将不同实验结果进行了比较和分析,实验结果表明,该文提出的方法具有良好的检索效果.     

基于ARM9的嵌入式pH值测控系统设计

本文介绍了一种基于ARM9微处理器S3C2410A的嵌入式pH值测控系统,包括S3C2410A自带的A/D转换器ADC,D/A转换芯片DAC8420等接口芯片的软硬件设计。利用微处理器S3C2410A丰富的I/O接口,通过74LS245电平转换芯片,解决了S3C2410A嵌入式处理器I/O接口输出电平与外设驱动电平不匹配的问题。     

基于DSP的相机标定系统设计

基于TI公司的TMS320DM643DSP芯片．完成了相机标定系统的总体设计。具体给出了系统硬件设计和系统软件设计．利用Tsai两步法实现了对相机的标定。标定算法使用C语言编程并在DEC643图像处理平台上验证和实现．充分利用了TMS320DM643强大的运算性能．有效地减轻了PC的运算负担。     

基于非线性兰姆波的热双金属残余应力表征

该文研究了热双金属带材的兰姆波非线性效应与温度、应力的关系,建立了非线性超声检测系统,结合X线衍射(XRD)法确定应力值。将热双金属分别加热到100℃、200℃和310℃,保温1 h后空冷,对比不同温度对非线性系数的影响,分析常态和热处理降应力后热双金属的非线性系数和应力值的关系。实验结果表明,热双金属在常温和经100℃、200℃加热后的非线性系数基本不变,而经过310℃稳定化热处理降低应力后,非线性系数明显降低;验证了热双金属中兰姆波二阶、三阶非线性系数对应力值敏感且随应力增大而增大,其均可用于表征残余应力状态;根据应力值与非线性系数的关系得到拟合函数,并验证了通过拟合函数计算应力的可行性,这为使用非线性系数评估应力提供了一种参考方法。     

基于多源融合的油纸绝缘套管缺陷辨识及绝缘状态评估

油浸纸绝缘套管作为变压器的关键组件,其绝缘受损会威胁变压器主设备的运行安全。针对此现状,提出一种基于多源融合的油纸绝缘套管缺陷辨识及绝缘状态评估方法。首先,根据实际运行工况制备典型缺陷试验套管,并开展频域介电响应、局部放电及红外热成像联合试验,辨识套管缺陷种类。然后,提取套管绝缘指标量,引入隶属度函数及状态得分算子,建立基于博弈论组合赋权法的套管绝缘状态评估模型。最后,分别采用组合赋权法和单一赋权法的评估模型,对正常以及缺陷套管进行算例分析。结果表明：联合试验可以准确辨识套管缺陷种类。组合赋权法弥补了单一赋权法评估结果片面的不足,且正常套管的模型评估分数均高于缺陷套管。评估结果与套管实际绝缘状态一致,验证了套管绝缘状态评估模型的正确性及有效性。     

Boosted Photocurrent via Heating BiFeo3 Thin Film for UV Photodetector at Wide Temperature Range

The current research on ferroelectric photovoltaic materials is concentrated on enhancing the output photocurrent. As solar cells operate at high temperatures, it is crucial to take into account the effect of increasing temperatures on ferroelectric photovoltaics. In this study, an LNO (lanthanum nickelate, LaNiO₃)/BFO (bismuth ferrate, BiFeO₃)/ITO (indium tin oxide) device is constructed on a mica substrate by sol–gel method. The device achieves output photocurrent enhancement at a wide temperature range (33–183 °C), with the largest photocurrent enhancement at 130 °C, which is 178% relative to room temperature, and the output power is also increased by 9.88 times. At the same time, compared with BFO bulk, it is found that the performance of BFO film is always higher than that of bulk in the test temperature range, and the output photocurrent of BFO film at room temperature is 104 times higher than that of bulk. This article investigates the effect of high temperatures on ferroelectric photovoltaics and also provides a strategy for enhancing the photovoltaic performance of ferroelectric films, providing guidance for future applications of ferroelectric films in flexible solar cells and other applications.     

Experimental investigation and thermodynamic assessment of the Zn–Cu–Sr ternary system

Zn–Cu–Sr alloys play a crucial role in the development of biodegradable implant materials based on zinc. The current study aimed to investigate the phase equilibria of the Zn–Cu–Sr ternary system in the Cu–Zn-rich region, through experimental analysis. For this purpose, fifteen and fourteen samples were respectively prepared and equilibrated at 350 and 400 °C, to determine the isothermal sections. The equilibrated alloys were then subjected to various analytical techniques such as scanning electron microscopy (SEM) equipped with energy dispersive spectrometry analysis (EDS), electron probe microanalysis (EPMA), and powder X-ray diffraction analysis (XRD). The analysis revealed the presence of five three-phase equilibria and ten two-phase equilibria in the two isothermal sections. Differential scanning calorimetry (DSC) was used to investigate the phase transformation temperature with constant values of 8 at. % Sr and 30 at. % Cu. The obtained experimental results were used to perform a thermodynamic assessment of the Zn–Cu–Sr system especial in Zn-rich region using the calculation of phase diagrams (CALPHAD) method. The modified quasi-chemical model (MQM) was used to model the liquid solution, while the compound energy formalism (CEF) was used to represent Gibbs free energies of the solid phases. The present obtained thermodynamic parameters were found to accurately reproduce the experimentally measured phase relationships in the Zn–Cu–Sr ternary system.     

Phase equilibria and microstructure development in Mg-rich Mg-Gd-Sr alloys: Experiments and CALPHAD assessment

Mg-Sr alloys are promising to fabricate orthopedic implants. The alloying of rare earth elements such as Gd may improve the comprehensive mechanical properties of Mg-Sr alloys. The information on the phase diagram and the microstructure development are required to design chemical composition and microstructure of Gd alloyed Mg-Sr alloys. The phase equilibria and the microstructure development in Mg-rich Mg-Gd-Sr alloys (Gd, Sr < 30 at. %) are experimentally investigated via phase identification, chemical analysis, and microstructure observation with respect to the annealed ternary alloys. The onset temperatures of liquid formation are measured by differential scanning calorimetry. A thermodynamic database of the Mg-rich Mg–Gd–Sr ternary system is developed for the first time via CALPHAD (CALculation of PHAse Diagram) approach assisted by First-Principles calculations. The thermodynamic calculations with the developed database enable a well reproduction of the experimental findings and the physical-metallurgical understanding of the microstructure formation in solidification and annealing.     

Rationally Designed Anti-Glare Panel Arrays as Highway Wind Energy Harvester

The anti-glare panels along highways can block the dazzling lights of opposing vehicles at night, playing an important role in the highway safety. Inspired by the highway anti-glare panels, wind energy harvesting triboelectric nanogenerator (AG-TENG) arrays to properly capture energy from highway moving vehicles is developed. A single AG-TENG installation module can achieve a high power density of 0.2 Wm⁻² at a wind speed of 3 m s⁻¹. This wind speed is too low to drive conventional wind energy harvesting equipment. The performance of the AG-TENG shows no degradation after 80 h of continuous operation (1 440 000 times). Thus, with the rational consideration and features, the system can generate enough power to drive internet of things (IoT) devices and environmental sensors, as well as offer wireless alarming and radio frequency identification vehicle monitoring. This study provides a promising strategy to properly harvest wind energy on highways using existing infrastructures under the condition of even no natural wind, showing broad application prospects in distributed environmental monitoring, intelligent highways, and the IoT.