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一种高精确度N相直线电机电感与磁力特性
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作者 蒋浩 周赣 +1 位作者 黄学良 张文春 《电机与控制学报》 EI CSCD 北大核心 2012年第12期1-6,共6页
为了设计一种N相高精确度直线电机,对电机定子和动子磁场分布、电感与磁力特性进行研究。根据定子电流层和动子永磁层的周期性分布特点,运用傅里叶级数方法得到磁场二维解析式。在此基础上,计算磁场随N值、气隙高度、电流层高度的变化... 为了设计一种N相高精确度直线电机,对电机定子和动子磁场分布、电感与磁力特性进行研究。根据定子电流层和动子永磁层的周期性分布特点,运用傅里叶级数方法得到磁场二维解析式。在此基础上,计算磁场随N值、气隙高度、电流层高度的变化趋势。通过对定子分布绕组的磁场进行积分,从而获得电感解析式,并以样机为例分析各次谐波电感特性。提出永磁阵列虚拟电流概念,结合改进的磁共能法计算出各次磁力脉动值。仿真结果表明:当气隙大于1 mm时,定子与动子磁场基本呈正弦分布,高次谐波电感与磁力脉动可忽略,仿真结果与解析解的误差小于5%。 展开更多
关键词 直线电机 Halbach永阵列 通与 电感特性 力特性 磁共能法
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永磁超环面电机结构参数对齿槽转矩的影响分析
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作者 刘欣 王洪达 《机械科学与技术》 CSCD 北大核心 2021年第4期500-507,共8页
为了分析永磁超环面电机结构参数对齿槽转矩的影响,在分析该电机齿槽转矩产生机理的基础上,针对该电机空间螺旋变截面的结构特点,将齿槽转矩的产生分为自转和公转两个分量进行分析;运用磁共能法推导了该电机齿槽转矩与输出转矩的数学表... 为了分析永磁超环面电机结构参数对齿槽转矩的影响,在分析该电机齿槽转矩产生机理的基础上,针对该电机空间螺旋变截面的结构特点,将齿槽转矩的产生分为自转和公转两个分量进行分析;运用磁共能法推导了该电机齿槽转矩与输出转矩的数学表达式,并采用有限元仿真验证了数学模型的有效可行性;分析了该电机重要结构参数对齿槽转矩削弱的同时对输出转矩幅值的影响规律。结果表明,内定子槽开口系数、行星轮齿的极弧系数和气隙值的合理选择,能够在削弱齿槽转矩波动的同时提高输出转矩的幅值,有效地提高永磁超环面电机的输出性能。 展开更多
关键词 超环面电机 螺旋变截面 齿槽转矩 磁共能法
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Preparation of MnxNi0.5-xZn0.5Fe2O4 Nanorods by the Co-precipitation Method 被引量:2
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作者 李巧玲 常传波 +1 位作者 张巍 张豪 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第6期680-684,745,746,共7页
MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2+, Ni2+, and Fe2+ in the lye. The phase, morphology, an... MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2+, Ni2+, and Fe2+ in the lye. The phase, morphology, and particle diameter were examined by the X-ray diffraction and transmission electron microscopy. The magnetic properties of the samples were studied using a vibrating sample magnetometer. nanorods with a diameter of 35 nm and an The results indicated that pure Ni0.5-xZn0.5Fe2O4 aspect ratio of 15 were prepared. It was found that the diametei of the MnxNi0.5-xZn0.5Fe2O4(0≤x≤0.5) samples increased, the length and the aspect .ratio decreased, with an increase in x value. When x=0.5, the diameter and the aspect ratio of the sample reached up to 50 nm and 7-8, respectively. The coercivity of the samples first increased and then decreased with the increase in the x value. The coercivity of the samples again increased when the x value was higher than 0.4. When x=0.5, the coercivity of the MnxNi0.5-xZn0.5Fe2O4 sample reached the maximal value (134.3 Oe) at the calcination temperature of 600 ℃. The saturation magnetization of the samples first increased and then. decreased with the increase in the x value. When x=0.2, the saturation magnetizat:ion of the sample reached the maximal value (68.5 emu/g) at the calcination temperature of 800 ℃. 展开更多
关键词 MnxNi0.5-xZn0.5Fe2O4 Nanorod CO-PRECIPITATION Magnetic property
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Homeopathy--A Regulation Therapy Healing Hypo- or Hyper-functions of Pathological Pathways by Magnetic Photons according to the Resonance Principle
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作者 Lenger Karin 《Journal of Life Sciences》 2017年第2期53-64,共12页
Since Lenger's detection of magnetic photons in homeopathic remedies by magnetic resonance the mystery of homeopathy comes to a solution. Homeopathy is a regulation therapy curing hypo- and hyper-functions of patholo... Since Lenger's detection of magnetic photons in homeopathic remedies by magnetic resonance the mystery of homeopathy comes to a solution. Homeopathy is a regulation therapy curing hypo- and hyper-functions of pathological pathways. It reacts according to the principle of resonance. The fundamental principles of homeopathy as proving, symptom picture, curing according to the Law of Similars and the production of homeopathic remedies over the Avogadro number by repeated dilution and succussion are explained to have the same frequencies so that the resonance principle can work. Pathological pathways are cured by using their highly potentized substrates, inhibitors and enzymes, given daily or each second day. This is in contradiction to the normal applied homeopathy. The efficacy of homeopathy now has a scientific base and is completely explained by applying biochemical and biophysical laws. 展开更多
关键词 Magnetic photons resonance principle magnetic frequencies homeopathic remedies homeopathic healing.
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An Improved Fixed-point Algorithm for Independent Component Analysis of Functional MRI Data
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作者 WENG Xiao-guang WANG Hui-nan QIAN Zhi-yu 《Chinese Journal of Biomedical Engineering(English Edition)》 2009年第2期78-83,共6页
The fixed-point algorithm and infomax algorithm are two of the most popular algorithms in independent component analysis(ICA).However,it is hard to take both stability and speed into consideration in processing functi... The fixed-point algorithm and infomax algorithm are two of the most popular algorithms in independent component analysis(ICA).However,it is hard to take both stability and speed into consideration in processing functional magnetic resonance imaging(fMRI)data.In this paper,an optimization model for ICA is presented and an improved fixed-point algorithm based on the model is proposed.In the new algorithms a small step size is added to increase the stability.In order to accelerate the convergence,an improvement on Newton method is made,which makes cubic convergence for the new algorithm.Applying the algorithm and two other algorithms to invivo fMRI data,the results show that the new algorithm separates independent components stably,which has faster convergence speed and less computation than the other two algorithms.The algorithm has obvious advantage in processing fMRI signal with huge data. 展开更多
关键词 independent component analysis(ICA) functional magnetic reasonance imaging(fMRI) Newton iteration
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