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背压变化速率对带支板流道内流场的影响 预览
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作者 田亮 刘宏宝 +2 位作者 郭赛男 王恩宇 段润泽 《燃烧科学与技术》 CAS CSCD 北大核心 2020年第1期1-9,共9页
为了进一步了解迟滞现象的机理,利用一个带有支板的矩形截面流道开展了动态反压特性的冷态数值仿真研究,分析了背压变化速率对流场结构的影响规律,捕获了由此引发的流动迟滞.研究结果表明,相较于稳态流动而言,在背压动态变化的条件下流... 为了进一步了解迟滞现象的机理,利用一个带有支板的矩形截面流道开展了动态反压特性的冷态数值仿真研究,分析了背压变化速率对流场结构的影响规律,捕获了由此引发的流动迟滞.研究结果表明,相较于稳态流动而言,在背压动态变化的条件下流场会出现明显的滞后性,背压变化速率越快滞后性越强.在固定的背压上升速率条件下,压力抬升起始位置处于匀加速运动状态,加速度与背压变化速率呈幂函数关系,在背压升高到最大值后的稳定过程中,压力抬升起始位置向上游减速运动,直至停止.在达到最大压比后的背压下降过程中,压力抬升起始位置仍然会向上游继续移动一段距离,这时若压力抬升起始位置移动到支板前缘上游,则支板前缘上游形成的激波串会稳定在支板前缘;若压力抬升起始位置未移动到支板前缘上游,则其变化路径仍与上升过程不重合,出现迟滞现象. 展开更多
关键词 超燃冲压发动机 迟滞 支板 背压 动态变化
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我国半导体显示产业财政补贴效应及研发效率研究 预览
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作者 张振华 《工业技术经济》 CSSCI 北大核心 2020年第2期151-160,共10页
本文对我国半导体显示产业财政补贴效应和研发效率进行研究,分析了财政补贴对企业自主研发投入的诱导效应以及研发投入与研发产出之间的关系,探讨了显示面板集成企业和上游企业财政补贴对自主研发投入诱导效应的异质性和研发效率的异质... 本文对我国半导体显示产业财政补贴效应和研发效率进行研究,分析了财政补贴对企业自主研发投入的诱导效应以及研发投入与研发产出之间的关系,探讨了显示面板集成企业和上游企业财政补贴对自主研发投入诱导效应的异质性和研发效率的异质性,同时研究了财政补贴对企业自主研发投入的滞后性以及研发投入对研发产出的滞后性。研究发现:财政补贴对企业自主研发投入具有明显的诱导效应;企业研发投入和研发产出显著正相关;财政补贴对上游企业自主研发投入的诱导性强于面板集成组装企业;财政补贴对企业自主研发投入的影响以及研发投入对产出的影响均具有一定的滞后性。本文为提升我国半导体显示产业竞争力提供了政策参考,对我国其他高科技产业的发展和产业政策的制定具有一定的参考借鉴意义。 展开更多
关键词 半导体显示产业 财政补贴 研发效率 异质性 滞后性 靶向性
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Effect of seismic design details on hysteresis performance of SRC-RC transfer columns 预览
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作者 Wu Kai Zhai Jiangpeng +2 位作者 Xue Jianyang Zhao Hongtie Chen Feng 《地震工程与工程振动:英文版》 SCIE EI CSCD 2020年第1期117-135,共19页
Four types of seismic design details were tested using 11 transfer column specimens and one comparison specimen of RC under low cyclic reversed loading. Test results show that diagonal cracks control the failure patte... Four types of seismic design details were tested using 11 transfer column specimens and one comparison specimen of RC under low cyclic reversed loading. Test results show that diagonal cracks control the failure pattern and damage occurs mainly in the RC section with weak shear capacity in the transfer columns. There is a large difference in the bearing capacity and ductility of the transfer columns according to the test results, which indicates that the strengthening effect of diverse structural measures is quite different. The section ratio of I-section-encased steel and the axial compression ratio also have a great influence on the bearing capacity and ductility. Although the bearing capacity of transfer columns with additional longitudinal bars and additional X bars is relatively large, they have poor deformation capacity. Setting more stirrups along the columns is the best structural measure to enhance the seismic performance. The studs on the I-sectionencased steel by welding can help to complete the stress transfer between the steel and concrete, and avoid performance degradation of the two materials due to bonding failure. 展开更多
关键词 seismic design details hysteresis performance steel reinforced concrete transfer column energy dissipation
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基于改进果蝇优化的压电精密定位平台迟滞Bouc-Wen模型辨识 预览
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作者 王龙飞 邓亮 刘萍 《计算机工程与应用》 CSCD 北大核心 2020年第2期242-247,共6页
提出一种基于改进果蝇优化算法(Improved Fruit fly Optimization Algorithm,IFOA)的压电精密定位平台迟滞特性的Bouc-Wen模型参数辨识方法。通过引入交叉因子和自适应搜索步长,IFOA可有效实现全局搜索与局部优化的动态平衡,并通过一种... 提出一种基于改进果蝇优化算法(Improved Fruit fly Optimization Algorithm,IFOA)的压电精密定位平台迟滞特性的Bouc-Wen模型参数辨识方法。通过引入交叉因子和自适应搜索步长,IFOA可有效实现全局搜索与局部优化的动态平衡,并通过一种新的搜索策略提高整体搜索效率和优化精度。将IFOA应用于压电精密定位平台迟滞Bouc-Wen模型的参数辨识。实验辨识结果验证了该方法的有效性和潜力。 展开更多
关键词 迟滞 果蝇优化算法 Bouc-Wen 压电精密定位平台 辨识
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压电陶瓷驱动器迟滞非线性建模及逆补偿控制 预览
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作者 刘鑫 李新阳 杜睿 《光电工程》 CAS CSCD 北大核心 2019年第8期23-30,共8页
自适应光学系统中的倾斜镜、变形镜通常是应用压电陶瓷驱动器来进行精密位移控制,但压电陶瓷驱动器都有较大的非线性迟滞效应,对系统定位性能造成了一定的影响。为了补偿迟滞现象,需要对迟滞效应进行建模。本文通过引入迟滞算子,使用贝... 自适应光学系统中的倾斜镜、变形镜通常是应用压电陶瓷驱动器来进行精密位移控制,但压电陶瓷驱动器都有较大的非线性迟滞效应,对系统定位性能造成了一定的影响。为了补偿迟滞现象,需要对迟滞效应进行建模。本文通过引入迟滞算子,使用贝叶斯正则化训练算法训练BP神经网络来构建压电陶瓷驱动器迟滞模型,以中国科学院光电技术研究所自主研制的压电陶瓷驱动器为对象开展了实验研究。实验结果表明,通过BP神经网络构建的压电陶瓷驱动器迟滞模型具有较准确的辨识能力,其中正模型的相对误差为0.0127,逆模型的相对误差为0.014。利用所建立的模型,压电陶瓷驱动器的非线性度从14.6%降低到了1.43%。 展开更多
关键词 自适应光学 压电陶瓷驱动器 迟滞效应 神经网络 迟滞算子
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Modeling and compensation of hysteresis for pneumatic artificial muscles based on Gaussian mixture models
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作者 XU JiHao XIAO MuBang DING Ye 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第7期1094-1102,共9页
This paper presents a new data-driven model of length-pressure hysteresis of pneumatic artificial muscles(PAMs) based on Gaussian mixture models(GMMs). By ignoring the high-order dynamics, the hysteresis of PAMs is mo... This paper presents a new data-driven model of length-pressure hysteresis of pneumatic artificial muscles(PAMs) based on Gaussian mixture models(GMMs). By ignoring the high-order dynamics, the hysteresis of PAMs is modeled as a first-order nonlinear dynamical system based on GMMs, and inversion of the model is subsequently derived. Several verification experiments are conducted. Firstly, parameters of the model are identified under low-frequency triangle-wave pressure excitations.Then, pressure signals with different amplitudes, shapes and frequencies are applied to the PAM to test the prediction performance of the model. The proposed model shows advantages in identification efficiency and prediction precision compared with a generalized Prandtl–Ishlinskii(GPI) model and a modified generalized Prandtl–Ishlinskii(MGPI) model. Finally, the effectiveness of the inverse model is demonstrated by implementing the feedforward hysteresis compensation in trajectory tracking experiments. 展开更多
关键词 HYSTERESIS MODELING HYSTERESIS COMPENSATION pneumatic artificial muscles (PAMs) GAUSSIAN MIXTURE model (GMM)
癔症性双眼闭目难睁发作1例
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作者 孟新珍 陈颖 +3 位作者 丁魁 刘惠霞 张灏 周超 《临床心身疾病杂志》 CAS 2019年第6期171-172,共2页
癔症的转换症状临床表现具有多样性,部分症状极为罕见,临床上易误诊.本研究对1例癔症性双眼闭目难挣患者的临床资料进行了分析,以期为临床诊治提供参考.
关键词 癔症 误诊 癔症转换症状 双眼闭目难睁
On stress-induced voltage hysteresis in lithium ion batteries:Impacts of surface effects and interparticle compression
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作者 JIN ChuanJian LI HaoLiang +3 位作者 SONG YiCheng LU Bo SOH A. K. ZHANG JunQian 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第8期1357-1364,共8页
Application of silicon in high capacity electrodes of lithium ion battery suffers from stress effects and, in turn, affects voltage performance of battery. This paper established a reaction-diffusion-stress coupled mo... Application of silicon in high capacity electrodes of lithium ion battery suffers from stress effects and, in turn, affects voltage performance of battery. This paper established a reaction-diffusion-stress coupled model and investigated the stress induced voltage hysteresis with consideration of diffusion induced stress, surface effects and interparticle compression. It was found stress and stress induced voltage hysteresis depended on particle size. In big particles, diffusion induced stress is dominant and leads to significant hysteresis in both stress and voltage, indicating energy dissipation due to stress effects. In small particles, e.g.,radius of dozens nanometers, diffusion induced stress was negligible while surface effects played dominant role, leading to nearly vanished voltage hysteresis shifting away from equilibrium potential. According to calculation, particle sizes around 100 nm are appropriate choice for electrode design as both diffusion induced stress and surface effects are insignificant. Finally,interparticle compression pushed the stress hysteresis to compressive side and led to early termination of lithiation at cut-off voltage. Denser electrode would enhance this effect. It indicated that there must be a limit of mixing ratio of silicon because higher interparticle compressive stress due to more introduced silicon would impede the battery from fully charged. 展开更多
关键词 LITHIUM ion battery VOLTAGE HYSTERESIS STRESS surface effect interparticle compression
CarSim/Simulink软件在教学中的应用 预览
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作者 杨浩 《汽车实用技术》 2019年第17期237-238,258共3页
当前,随着科学技术的不断发展,尤其是"人工智能"引起广泛关注后,汽车领域的新技术更新周期趋于短时间化。而教学所用的指定教材与老师所参考的教学讲义对于新领域知识的更新具有一定的滞后性。这将导致教师的"教"... 当前,随着科学技术的不断发展,尤其是"人工智能"引起广泛关注后,汽车领域的新技术更新周期趋于短时间化。而教学所用的指定教材与老师所参考的教学讲义对于新领域知识的更新具有一定的滞后性。这将导致教师的"教"与学生的"学"未能适应企业的"产",更无法较好与"产""学""研"相融合。文章基于汽车动力学仿真软件CarSim具有更新速度快、能实时模拟各种工况、便于修改车辆参数和Simulink软件具有强大的控制算法功能等优势,提出将汽车动力学仿真软件CarSim与Simulink联合仿真,应用于教学工作中,有助于改进教学质量,契合汽车新领域,推进"产""学""研"相融合的发展模式。 展开更多
关键词 人工智能 教学 滞后性 CARSIM SIMULINK
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基于多源遥感数据的干旱监测研究 预览 被引量:1
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作者 孙嵩松 王喜民 《山东农业科学》 2019年第2期150-157,共8页
及时准确地监测干旱可以预防其造成的农作物减产。归一化植被指数(NDVI)在监测植被生长状态、农业干旱方面都表现出了良好的特性。但NDVI对干旱的响应具有一定的滞后性。为了及时准确地监测旱情,本研究将热带降雨测量卫星(TRMM)的降雨... 及时准确地监测干旱可以预防其造成的农作物减产。归一化植被指数(NDVI)在监测植被生长状态、农业干旱方面都表现出了良好的特性。但NDVI对干旱的响应具有一定的滞后性。为了及时准确地监测旱情,本研究将热带降雨测量卫星(TRMM)的降雨数据与NDVI结合起来,构建了基于旬尺度的MNDVI干旱监测模型,并以吉林省农作物生长季为例,通过与历史数据、土壤湿度、叶面积指数(LAI)作相关性分析对其进行验证。结果表明:MNDVI监测的干旱变化图与历史记录有很好的吻合性,表明MNDVI监测干旱的准确性好;将MNDVI和NDVI分别与10cm和20cm土层的土壤湿度进行相关性分析,结果表明MNDVI在一定程度上可以消除NDVI监测干旱方面存在的滞后性;将MNDVI和降雨状态指数(PCI)分别与LAI进行时间序列分析,发现MNDVI与LAI有良好的一致性,而PCI与LAI没有一致性,表明MNDVI对植被的生长状态能够及时响应,可以用来监测农业旱情。 展开更多
关键词 干旱 NDVI 滞后性 TRMM 监测模型
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基于电流轨迹的逆变器开路故障在线故障诊断的一种新方法 预览
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作者 李凯迪 陈春阳 +3 位作者 陈特放 成庶 伍珣 向超群 《中南大学学报:英文版》 SCIE EI CAS CSCD 2019年第3期743-758,共16页
逆变器的安全性与可靠性是电力电子系统稳定运行的不可或缺的条件,而逆变器的故障大部分是由其中的开关元器件运行故障所引起的。本文以滞环电流控制的逆变器作为研究对象,提出了一种可适用于各种控制策略下的开路故障诊断方法。逆变器... 逆变器的安全性与可靠性是电力电子系统稳定运行的不可或缺的条件,而逆变器的故障大部分是由其中的开关元器件运行故障所引起的。本文以滞环电流控制的逆变器作为研究对象,提出了一种可适用于各种控制策略下的开路故障诊断方法。逆变器的开路故障会导致输出相电流畸变,可将此现象作为一个故障特征,并结合比较故障发生前后入相电流方向,实现在半个周期内对开路故障的诊断及定位。此外,该诊断方法既不需要获取系统控制信号,也不需要添加额外传感器。最后,通过dSPACE半实物实验平台,对所提出方法的有效性、可靠性及局限性进行了验证和分析。 展开更多
关键词 故障诊断 滞环 逆变器 故障定位
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基于Duhem算子的极限学习机迟滞建模
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作者 潘海鹏 姜慧斌 赵新龙 《控制工程》 CSCD 北大核心 2019年第3期566-569,共4页
在高精度定位领域中,压电执行器(PEAs)被广泛应用,但其存在着固有的迟滞非线性特性,大大降低了它的控制性能。为了消除迟滞影响,提高压电执行器的控制精度,需建立其迟滞非线性模型。通过引入Duhem迟滞算子来将迟滞的多值映射转化为一对... 在高精度定位领域中,压电执行器(PEAs)被广泛应用,但其存在着固有的迟滞非线性特性,大大降低了它的控制性能。为了消除迟滞影响,提高压电执行器的控制精度,需建立其迟滞非线性模型。通过引入Duhem迟滞算子来将迟滞的多值映射转化为一对一映射关系,应用极限学习机算法逼近迟滞状态与迟滞输出的关系进行迟滞建模。最后应用实验仿真验证了建模方法的有效性。该方法训练速度快、建模精度高,便于实现。 展开更多
关键词 压电执行器:迟滞 Duhem算子 极限学习机
Effects of yaw-roll coupling ratio on lateraldirectional aerodynamic characteristics
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作者 Lin SHEN Da HUANG Genxing WU 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第2期272-280,共9页
Experimental investigation of large amplitude yaw-roll coupled oscillations was conducted in a low-speed wind tunnel using an aircraft configuration model. A special test rig was designed and constructed to provide di... Experimental investigation of large amplitude yaw-roll coupled oscillations was conducted in a low-speed wind tunnel using an aircraft configuration model. A special test rig was designed and constructed to provide different coupled motions from low to high angles of attack.A parameter ‘‘coupling ratio' was introduced to indicate the extent of yaw-roll coupling. At each pitch angle, seven coupling ratios were designed to study the yaw-roll coupling effects on the lateraldirectional aerodynamic characteristics systematically. At high angles of attack, the damping characteristics of yawing and rolling moments drastically varied with coupling ratios. In the coupled motions with the rotation taking place about the wind axis, the lateral-directional aerodynamic moments exhibited unsteady characteristics and were different from the ‘‘quasi-steady' results of the rotary balance tests. The calculated results of the traditional aerodynamic derivative method were also compared with the experimental data. At low and very high angles of attack, the aerodynamic derivative method was applicative. However, within a wide range of angles of attack, the calculated results of aerodynamic derivative method were inconsistent with the experimental data, due to the drastic changes of damping characteristics of lateral-directional aerodynamic moments with yaw-roll coupling ratios. 展开更多
关键词 High ANGLES of ATTACK HYSTERESIS Lateral-directional aerodynamic characteristics UNSTEADY Yaw-roll coupling
《航空高压直流供电系统中三相Vienna整流器的控制策略研究》之四——连续和断续模式下Buck变换器的滞环滑模控制设计 预览 被引量:1
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作者 吴辰 李颖晖 +4 位作者 刘远飞 朱喜华 刘聪 韩建定 谢喜太 《大电机技术》 2019年第4期71-76,共6页
为提升Buck变换器的工作性能,降低其作为电子负载对Vienna整流器的不利影响,提出了一种在连续和断续工作模式下的滞环滑模控制策略。首先,设计了以输出电压误差和其微分值为状态量的滑模面,通过对Buck变换器二阶误差模型的相平面分析,... 为提升Buck变换器的工作性能,降低其作为电子负载对Vienna整流器的不利影响,提出了一种在连续和断续工作模式下的滞环滑模控制策略。首先,设计了以输出电压误差和其微分值为状态量的滑模面,通过对Buck变换器二阶误差模型的相平面分析,确定了满足广义滑模条件的区域和连续导电模式、断续导电模式的边界及收敛情况;最终通过仿真和实验銅了上述分析的结论。 展开更多
关键词 BUCK变换器 滑模控制 滞环 性能分析
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Magnetoresistance hysteresis in topological Kondo insulator SmB6 nanowire
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作者 孔令剑 周勇 +2 位作者 宋化鼎 俞大鹏 廖志敏 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第10期105-108,共4页
SmB6, a topological Kondo insulator, with a gapped bulk state and metallic surface state has aroused great research interest. Here, we report an exotic hysteresis behavior of magnetoresistance in individual SmB6 nanow... SmB6, a topological Kondo insulator, with a gapped bulk state and metallic surface state has aroused great research interest. Here, we report an exotic hysteresis behavior of magnetoresistance in individual SmB6 nanowire in a temperature range in which both surface and bulk states contribute to the total conductance. Under a magnetic field parallel to the SmB6 nanowire, the resistance suddenly increases at the turning point from up-sweep to down-sweep of the magnetic field. The magnetoresistance hysteresis loops are well consistent with the magnetocaloric effect. Our results suggest that the SmB6 nanowires possess potential applications in the magnetic cooling technology. 展开更多
关键词 TOPOLOGICAL KONDO insulator MAGNETOCALORIC effect MAGNETORESISTANCE HYSTERESIS
有机金属卤化物钙钛矿中的离子迁移现象及其研究进展 预览
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作者 王继飞 林东旭 袁永波 《物理学报》 SCIE EI CAS CSCD 北大核心 2019年第15期90-110,共21页
近年来,卤化物钙钛矿太阳能电池由于其诸多技术优势引起了普遍的关注,其效率在几年内达到了认证的24.2%,接近目前已经民用化的晶体硅太阳能电池.卤化物钙钛矿在外加电场作用下除了具有电荷传输能力外,还表现出离子迁移现象,是一种兼具... 近年来,卤化物钙钛矿太阳能电池由于其诸多技术优势引起了普遍的关注,其效率在几年内达到了认证的24.2%,接近目前已经民用化的晶体硅太阳能电池.卤化物钙钛矿在外加电场作用下除了具有电荷传输能力外,还表现出离子迁移现象,是一种兼具半导体和离子导体特性的材料.离子迁移不仅直接改变了钙钛矿晶体的局部化学配比,而且会对材料的电学性质乃至相应器件的工作机理产生极大影响.本文总结了离子迁移的形成机制、基本特征及其对器件工作过程的影响(如可翻转的光伏现象、电流迟滞现象等),介绍了一些关于抑制离子迁移的最新研究进展.目前关于钙钛矿材料中的离子迁移现象的认识仍不全面,深入理解卤化物钙钛矿材料中的离子迁移现象对推动钙钛矿太阳能电池的发展和应用十分重要. 展开更多
关键词 钙钛矿 太阳能电池 离子迁移 电流迟滞 稳定性
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A novel analytical model for hysteresis loops of exchange-coupled hard-soft magnets
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作者 Jing Zou Laichuan Shen +5 位作者 Lei Qiu Youhua Feng Chan Luo Xue Liang Li Zhao Guoping Zhao 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第10期1034-1039,共6页
Hard/soft permanent magnets have attracted a lot of attention because of their rich magnetic properties and their potential for realizing giant energy products. However, energy products obtained by scientists in exper... Hard/soft permanent magnets have attracted a lot of attention because of their rich magnetic properties and their potential for realizing giant energy products. However, energy products obtained by scientists in experiments are much smaller than the theoretical values, which has been studied by various analytical and numerical methods. The famous Stoner-Wohlfarth model(S-W model) is too simple to give the hysteresis loops whereas the intensively used variational method is too complicated to reveal the underlying mechanism in a simple form. The analytical model proposed in this paper maintains a balance between simplicity and precision, where the spins in the soft layer rotate fast and coherently with the applied field while those in the hard layer response to the applied field much slower but also coherent. An exchange coupling is provided to maintain the exchange spring which drags the spins in the hard layer to follow those in the soft layer. Similar to the more sophisticated model, the calculated hysteresis loops display three typical magnetic phases, i.e., the rigid composite magnet, the exchange spring and decoupled magnet, whereas the simple SW model can only give one single phase, i.e., the rigid composite one. In addition to the hysteresis loop, the energy product and the nucleation fields have been calculated and compared with those calculated by other methods, which justifies our model.Careful comparisons show that our calculations are in good agreement with the experimental results and other theoretical results, especially for the important coercivity value and the related mechanism. 展开更多
关键词 PERMANENT MAGNETS Analytical model HYSTERESIS LOOPS NUCLEATION fields Rare earths
Simulation and Experiment Based on FSMLC Method with EUPI Hysteresis Compensation for a Piezo-Driven Micro Position Stage
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作者 GAO Jinhai HAO Lina +2 位作者 CHENG Hongtai CAO Ruimin SUN Zhiyong 《系统科学与复杂性学报:英文版》 CSCD 2019年第5期1340-1357,共18页
Micro/nano positioning technologies have been attractive for decades in industrial and scientific applications fields. The actuators have inherent hysteresis that can cause system unexpected behave in some extend. In ... Micro/nano positioning technologies have been attractive for decades in industrial and scientific applications fields. The actuators have inherent hysteresis that can cause system unexpected behave in some extend. In this research, the authors used extented unparallel Prandtl-Ishlinshii(EUPI)models to represent the input-output relationship of a piezo-driven micro position stage. Integral inverse(I-I) compensator is used for compensating the hysteresis characteristics of the micro positioning stage and compared with direct inverse(D-I) compensator and inverse model(I-M) compensator. However,the accuracy and the robustness of the I-I compensator are worse when there is noisy in the system,a novel sliding-mode-like-control with EUPI(SMLC-EUPI) method was proposed and analyzed by different trajectory tracking experiments in Matlab environment. Though the above strategies can alleviate most deviation, the adjustment of the SMLC’s parameters is very complex. So the fuzzy method is used to adjust these parameters and be verified by trajectory tracking experiments. Finally,for validating the proposed control method, the paper did the corresponding experiment in microscope with CMOS and obtained convincing results. 展开更多
关键词 EUPI fuzzy HYSTERESIS COMPENSATION MICRO POSITION STAGE sliding-mode-like-control
Hysteresis of a periodic or leaking western boundary current flowing by a gap 预览
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作者 Xinxin Song Dongliang Yuan Zheng Wang 《海洋学报:英文版》 SCIE CAS CSCD 2019年第4期90-96,共7页
A 1.5-layer quasi-geostrophic reduced gravity model is used to study the hysteresis of a periodic or leaking western boundary current(WBC)flowing by a gap.When the periods of the WBC variations are much longer than th... A 1.5-layer quasi-geostrophic reduced gravity model is used to study the hysteresis of a periodic or leaking western boundary current(WBC)flowing by a gap.When the periods of the WBC variations are much longer than the Rossby adjustment time scales of the circulation in the vicinity of the gap,the Hopf bifurcations during the Reincrease and Re-decrease loops are delayed to produce a new domain of hysteresis of the Reynolds numbers,and the critical Reynolds numbers of the WBC regime transitions change significantly,with the domain of the hysteresis Reynolds number larger for shorter periodic forcing.When the periods of the WBC variations are comparable to those of the Rossby adjustment time scales of the circulation in the vicinity of the gap,the WBC path inside the gap becomes periodic without hysteresis.The intrusion of the WBC into the western basin generally gets smaller as the period decreases.In addition,the partial leakage of the WBC transport through the gap into the western basin is found to have significant impact on the hysteresis loop of the WBC path when the leaked transport is larger than 1/2 of the WBC.Both the intrusion extent and the critical Reynolds numbers of the WBC regime transition are changed,and the larger the throughflow transport,the larger the change. 展开更多
关键词 HYSTERESIS PERIODIC WESTERN BOUNDARY current THROUGHFLOW
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基于Modbus协议的变频风机优缺点 预览
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作者 牛峥 张远霞 +1 位作者 张东海 宋利峰 《通信电源技术》 2019年第12期200-201,共2页
Modbus协议是目前工业化和自动化通信领域应用最广泛的工业通信标准协议之一。由于它的技术开放性、可扩充性和技术标准化优势,使它成为了一个具有通用性的工业通信标准。有了它,不同网络厂商的监控产品系统可以简单可靠地同时接入不同... Modbus协议是目前工业化和自动化通信领域应用最广泛的工业通信标准协议之一。由于它的技术开放性、可扩充性和技术标准化优势,使它成为了一个具有通用性的工业通信标准。有了它,不同网络厂商的监控产品系统可以简单可靠地同时接入不同网络,实现系统的集中自动监控、分散控制等功能。基于此,重点讨论了基于Modbus协议的变频风机的优缺点。 展开更多
关键词 MODBUS 变频风机 滞后性
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