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利用牛顿力学中的稳定性理论对磁悬浮陀螺稳定悬浮的条件进行了分析,在实验上对磁悬浮陀螺底座磁场的空间分布进行了测量,将理论分析和测量的数据结合起来从理论上预测陀螺稳定悬浮的区域范围,再将实验上实际观察到的稳定悬浮区域与之对比,得到了一致性的结论,由此得出了磁悬浮陀螺稳定悬浮的条件. 相似文献
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磁性液体的二阶磁悬浮原理是一个新颖的磁学实验,将它引入物理实验中,提升为设计性研究性实验项目,培养学生的创新思维和科学素养。使用圆片状钕铁硼永磁体作为实验材料,利用自行设计的非磁性浮子,研究了永磁体在磁性液体中的悬浮高度和二阶磁浮力。研究发现,永磁体厚度相同时,随永磁体直径增加,永磁体的悬浮高度逐渐变高,说明磁性液体对永磁体的二阶磁浮力增大,主要是由于随永磁体直径增加,其磁性增强所致,实验结果与理论研究一致。永磁体直径相同时,随永磁体厚度增加,磁性液体对永磁体的二阶磁浮力逐渐增大,导致永磁体的悬浮高度也逐渐增高。 相似文献
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通过对永磁体辅助下单畴GdBCO超导体和方形永磁体在液氮温度、 零场冷、 轴对称情况下磁悬浮力的测量, 研究了三种不同组态中辅助永磁体的引入方式对单畴GdBCO超导块材磁场分布及其磁悬浮力的影响. 实验结果表明, 如果处在超导体上方的测量用方形永磁体N极向下, 则在轴对称情况下, 当方形辅助永磁体N极向上与超导体下表面贴在一起时, 超导体的最大磁悬浮力从没有引入辅助永磁体磁化的14.3 N增加到31.8 N, 提高到222%; 当方形辅助永磁体放置在超导体上表面、 N极垂直向上且场冷后去掉辅助永磁体时, 超导体的最大磁悬浮力从没有引入辅助永磁体磁化的14.3 N增加到21.6 N, 增加到151%; 当方形辅助永磁体放置在超导体上表面、 N极垂直向下且场冷后去掉方形辅助永磁体时, 超导体的最大磁悬浮力从没有引入辅助永磁体磁化的14.3 N减小到8.6 N, 减小为无辅助永磁体时的60%.这些结果说明, 只有通过科学合理地设计超导体和永磁体的组合方式, 才能获得较高的磁场强度, 有效地提高超导体的磁悬浮力特性, 该结果对促进超导体的应用具有重要的指导意义. 相似文献
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通过对方形永磁体和方形辅助永磁体在液氮温度下对GdBCO超导体磁化后超导磁悬浮力的测量, 研究了两种组态中方形辅助永磁体对超导体的磁化方式对单畴GdBCO超导块材磁场分布及其磁悬浮力的影响. 结果发现, 方形辅助永磁体的下表面和超导体上表面保持在同一个水平面上, 磁化进程中方形辅助永磁体在GdBCO超导体上表面水平面内沿直径方向的位置x从–15 mm增加到+15 mm时, 超导磁悬浮力大小与超导体的磁化方式有着密切关系(以Z=0.1 mm为例): 1) 当方形辅助永磁体N极垂直向上且场冷后去掉辅助永磁体时, 超导体最大磁悬浮力先从16.7 N增大到23.1 N, 再减小到16.6 N; 2) 当方形辅助永磁体N极垂直向下且场冷后去掉辅助永磁体时, 超导体最大磁悬浮力先从17.7 N减小到7 N, 再增加到17.6 N; 3) 两种组态中最大磁悬浮力不相等, 而且与零场冷下的最大磁悬浮力(17.1 N)也不同. 这些结果说明: 只有通过科学合理地设计超导体和永磁体的组合方式, 才能获得较高的磁场强度, 有效地提高超导体的磁悬浮力特性, 该结果对促进超导体的应用具有重要的指导意义.
关键词:
单畴GdBCO
永磁体
捕获磁场
磁悬浮力 相似文献
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单晶硅球间微量密度差异测量是阿伏伽德罗常数量子基准定义的重要研究内容, 也是半导体产业中高纯度单晶硅制备工艺质量控制的主要方法. 为了改善现有非接触相移干涉法测量装置复杂和静力称重法测量不确定度低的特点, 根据单晶硅密度精密测量需要, 实现了一种基于静力悬浮原理的单晶硅球密度相对参比测量方法. 通过改变静压力和温度进行三溴丙烷和二溴乙烷混合液体密度的微量调节, 分别使两个待测单晶硅球在液体中悬浮, 根据悬浮状态时的液体温度和悬浮高度计算出待测单晶硅球密度差值. 通过双循环水浴和PID温度控制系统实现±100 μK的恒温液体测量环境. 通过图像识别和迭代拟合算法实现单晶硅球悬浮高度的测量. 使用PID静压力控制系统实现单晶硅球的稳定悬浮控制, 同时减少Joule-Thomson效应引起的液体温度改变. 利用静力悬浮模型中的温度变化和静压力变化线性关系准确测量出标准液体的压缩系数. 试验结果表明, 这种测量方法可以避免液体液面张力的影响, 测量相对标准不确定度达到2.1×10-7, 能够实现单晶硅球密度差值的精密测量. 相似文献
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讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系,指出引力场强g并不是与r的平方成反比,这是由于银河系的大小和形状不能忽略造成的.强调了万有引力定律的适用条件. 相似文献
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R. A. Vadov 《Acoustical Physics》2005,51(3):265-270
The disagreement between the experimental and calculated positions of the first convergence zone are known from many publications. The most probable cause for such a disagreement, namely, the incorrect specification of the input data for the calculations, is considered. The lack of simultaneity between the hydrological surveys of the region and the acoustic experiments is emphasized. The experimental data obtained by the author in five ocean regions are presented. These data characterize the diurnal variability of the distance from the source to the nearest boundary of the convergence zone. The relations proposed by different researchers for calculating the sound speed from the temperature, salinity, and hydrostatic pressure are analyzed. It is shown that these relations lead to a substantial difference in the estimated depth dependence of the hydrostatic gradient of the sound speed. The position of the first convergence zone is calculated for the propagation conditions determined by vertical temperature and salinity profiles with the subsequent recalculation of these profiles into sound speed profiles by using eight different formulas known from the literature. It is shown that different formulas lead to different values of the distance to the first zone; this difference is substantially greater than that between the calculations and experiment. The necessity of improving the recalculation relations in view of the experimental data on sound propagation in natural oceanic waveguides, including the data on the actual positions of the convergence zones, is emphasized. 相似文献
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J. Šlechta 《Czechoslovak Journal of Physics》1968,18(10):1299-1308
On the basis of the classical theory of radiation produced in incomplete Coulomb interaction, a formula is derived for the coefficient of the bremsstrahlung of fully ionized plasma. In the region of rectilinear approximation a comparison is made with the results of the quantum formula derived from the Born approximation. Furthermore, the influence of dispersion upon the emission coefficient is taken into account; some relations for the region of dispersion are given. 相似文献
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The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration ne, degree of 6 ionnization α) from concentration of lithium additive. 相似文献
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SJ Rose 《Contemporary Physics》2013,54(2):109-121
In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required. 相似文献
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Technical Physics - The object of this work is the apokamp—a new type of plasma jet, which is formed from a bright offshoot emerging at the bending point of a channel of a high-voltage... 相似文献
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We consider associated production of squarks and gluinos with the lightest supersymmetric particle (LSP), or states nearly degenerate in mass with it. Though sub-dominant to pair production of color SU(3)-charged superpartners, these processes are directly sensitive to the wavefunction composition of the lightest neutralinos. Exploiting event-shape variables - including some introduced here for the first time - we are able to identify the composition of the LSP by selecting events involving a single high-pT jet recoiling against missing transverse energy. We illustrate the proposed technique on a set of benchmark cases and propose methods for applying these results in more realistic experimental environments. 相似文献