【目的】准确监控和预测配电网设备所处环境相对湿度的状态和变化趋势。【方法】通过分析影响相对湿度的相关因素,提出了一种权重调整(Weight of adjust,AW)和遗传算法(Genetic algorithms,GA)相结合的BP算法(AW-GA-BP算法),在此算法的...【目的】准确监控和预测配电网设备所处环境相对湿度的状态和变化趋势。【方法】通过分析影响相对湿度的相关因素,提出了一种权重调整(Weight of adjust,AW)和遗传算法(Genetic algorithms,GA)相结合的BP算法(AW-GA-BP算法),在此算法的基础上,建立了对配电网设备所处环境相对湿度变化的神经网络预测模型,并将此算法应用到项目组为云南省某供电局开发的配电网运行环境智能化监测系统上,利用该监测系统所采集到的数据,将不同采样试验数据分别作为训练样本和验证样本,对比研究了AW-GA-BP算法、GA-BP算法和标准BP算法的预测误差。【结果】基于AW-GABP算法预测得到的相对湿度百分误差平均值是4.28%,基于GA-BP算法预测得到的相对湿度百分误差平均值是8.87%,基于标准BP算法预测得到的百分误差平均值是14.64%。【结论】基于AW-GA-BP算法所建模型的相对湿度预测平均误差更小,为预测配电网设备所处环境相对湿度提供了一种更为准确的方法。展开更多
Sandwich-structured flexible sensors based on graphene have high sensitivity and stability.When graphene is combined with a flexible substrate in a sandwich structure,the weak bonding between them compromises the sens...Sandwich-structured flexible sensors based on graphene have high sensitivity and stability.When graphene is combined with a flexible substrate in a sandwich structure,the weak bonding between them compromises the sensor's stability and sensitivity at low strains.This presents challenges in monitoring subtle physiological activities,such as hand bending and pulse rate.For this purpose,laser-induced graphene(LIG)is proposed to be used to prepare flexible sensors in order to improve the sensitivity and stability of the sensors at low strains.Polydimethylsiloxane(PDMS)with low modulus and polyimide(PI)with rich carbon content are selected as precursor materials for LIG,and graphene is formed through laser induction.Subsequently,silver nanowires(Ag NWs)solution is added to LIG to give the sensor low strain and high sensitivity performance.When the PI/PDMS ratio is 1:3,the Ag NWs/LIG flexible strain sensor exhibits excellent sensitivity(GF=778.468)over a small strain range(8.76%-11.25%).Meanwhile,the sensor still shows excellent stability after 2000 cycle experiments.The Ag NWs/LIG flexible strain sensor shows good performance when placed on the back of the hand,around the eyes,etc.It is demonstrated that Ag NWs/LIG flexible strain sensors have good application potential in human physiological activity monitoring,health management and medical fields,and provide a low-strain,high-sensitivity sensor design strategy for flexible wearable devices.展开更多
文摘【目的】准确监控和预测配电网设备所处环境相对湿度的状态和变化趋势。【方法】通过分析影响相对湿度的相关因素,提出了一种权重调整(Weight of adjust,AW)和遗传算法(Genetic algorithms,GA)相结合的BP算法(AW-GA-BP算法),在此算法的基础上,建立了对配电网设备所处环境相对湿度变化的神经网络预测模型,并将此算法应用到项目组为云南省某供电局开发的配电网运行环境智能化监测系统上,利用该监测系统所采集到的数据,将不同采样试验数据分别作为训练样本和验证样本,对比研究了AW-GA-BP算法、GA-BP算法和标准BP算法的预测误差。【结果】基于AW-GABP算法预测得到的相对湿度百分误差平均值是4.28%,基于GA-BP算法预测得到的相对湿度百分误差平均值是8.87%,基于标准BP算法预测得到的百分误差平均值是14.64%。【结论】基于AW-GA-BP算法所建模型的相对湿度预测平均误差更小,为预测配电网设备所处环境相对湿度提供了一种更为准确的方法。
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZDK202300606)Chongqing Municipal Natural Science Foundation(Grant No.CSTB2022NSCQ-MSX0380)+1 种基金National High-end Foreign Experts Introduction Plan(Grant No.G2022035005L)Chongqing Talent Plan of Overall Rationing System Project(Grant No.CQYC202203091156)。
文摘Sandwich-structured flexible sensors based on graphene have high sensitivity and stability.When graphene is combined with a flexible substrate in a sandwich structure,the weak bonding between them compromises the sensor's stability and sensitivity at low strains.This presents challenges in monitoring subtle physiological activities,such as hand bending and pulse rate.For this purpose,laser-induced graphene(LIG)is proposed to be used to prepare flexible sensors in order to improve the sensitivity and stability of the sensors at low strains.Polydimethylsiloxane(PDMS)with low modulus and polyimide(PI)with rich carbon content are selected as precursor materials for LIG,and graphene is formed through laser induction.Subsequently,silver nanowires(Ag NWs)solution is added to LIG to give the sensor low strain and high sensitivity performance.When the PI/PDMS ratio is 1:3,the Ag NWs/LIG flexible strain sensor exhibits excellent sensitivity(GF=778.468)over a small strain range(8.76%-11.25%).Meanwhile,the sensor still shows excellent stability after 2000 cycle experiments.The Ag NWs/LIG flexible strain sensor shows good performance when placed on the back of the hand,around the eyes,etc.It is demonstrated that Ag NWs/LIG flexible strain sensors have good application potential in human physiological activity monitoring,health management and medical fields,and provide a low-strain,high-sensitivity sensor design strategy for flexible wearable devices.
