带奇异电流密度面无力磁场及其稳定性

从Bernstein磁流体力学能量原理出发，讨论圆柱坐标下一类带奇异电流密度面的一维单参数无力磁场的稳定性，这类无力磁场在参数空间同时存在稳定区和不稳定区，其稳定性完全由磁螺距在圆柱轴邻域内的径向分布决定，与位于磁场边界处的奇异电流密度面无关。     

Magnetic energy release near accreting black holes

The observed non-thermal emission from accreting compact objects is often understood in terms of the expected magnetic activity of accretion disks. This review discusses the constraints on this view point that can be obtained from, principally, the X-ray spectra and the X-ray variability of black hole candidates.Furthermore, the traditional view of an accretion disk corona, put forward as the source of the non-thermal emission, analogous to the solar corona is shown to be wrong on a few important points. Firstly, the density in the equilibrium accretion disk corona is extremely low. A reasonable plasma density is retained by pair production processes similar to those existing in the pulsar magnetosphere. Secondly, the dominant resistivity in the accretion the disk on the current carrying electrons.     

粉末烧结Nd15Fe77B8永磁合金的矫顽力特征

通过测量粉末烧结Ｎｄ１５Ｆ３７７Ｂ８永磁合金的充磁和退磁曲线，结合金相组织及磁畴观察分析，证明该合金的矫顽力是由畴壁的钉扎来控制。     

红宝石球轴承在低温条件下的静态热导

通过红宝石球轴承与不锈钢球轴承的实测热导比较，说明了在低温条件下红宝石球轴承的热导较高，热导受温度和负荷的影响较大，但是红宝石球轴承的接触热导较小。     

非晶态（Fe0.5Ni0.5）80—xCrxP14B6合金薄带的磁谱的研究

以阻抗电桥法对非晶态(Fe_(0.5)Ni_(0.5))_(80-z)Cr_zP_(14)B_6(x=0,1,2,3,4,6,10)合金薄带的淬态和等温退火后样品的磁谱进行了测量。结果表明:退火后相对起始磁导宰μ_(?)提高了3.6～6倍,截止频率f_c下降,磁损耗μ_2的磁谱出现了共振峰。同时,等温退火处理对各样品相对起始磁导率的影响比改变Cr元素含量x要大得多。     

滑动轴承最佳稳定性的优化方法

在求解短轴承非线性油膜力作用下轴心涡动轨迹的基础上，给出了轴颈瞬时涡动能量的表达式，建立了以涡动能量的时间积分为最小的具有最佳稳定性的滑动轴承参数优化模型，并采用最优控制理论对这一模型进行了求解，结合算例说明轴承最佳参数的确定方法     

声级计抗电磁场辐射干扰试验研究

介绍了射频电磁场对声级计进行电磁辐射干扰的详细情况以及利用工频磁场测试装置进行声级计抗工频磁场干扰的研究设计     

Effects of Different Molten-salt on the Synthesis of Hexagonal Barium Ferrite

Hexagonal-plate BaFe12O19 nano-particles were prepared by combining the co-precipitation and molten-salt method. The effects of molten-salt NaCl on the products have been compared with those of KCl. The X-ray diffraction analysis, the environment scanning electron microscopy and the vibrating sample magnetometer were used to measure their characteristics. The results show that the mol- ten-salt KCl is helpful to obtain pure phase while the molten-salt NaCl will prompt the crystallinity of particles to increase. It is also found that, given the molten-salt of NaCl and that of KCl of the same quantity, the particles formed are also the same size. The size of particles slightly increases as the quantity of the salt increases. Moreover, the sample prepared under 200% NaCl salt system has magnetization of 71.5 emu/g.     

新型挠性气体动压推力轴承

 本文提出一种结构简单、稳定性好的新型挠性气体动压推力轴承,并对其进行了理论分析。即将可压缩二维气体动压润滑方程与弹性板的变形结合起来,用等参数有限元法计算轴承的气膜厚度分布和压力分布。试验表明,新型轴承能在高速下正常运转并承受一定载荷,稳定性能良好。     

航天发射用磁悬浮助推发射系统概念研究

针对日益增加的航天发射成本问题和安全、可靠、低成本航天发射方式的需求,阐述了磁悬浮助推发射概念及其优越性.初步分析了磁悬浮助推发射系统组成及各分系统功能.通过比较电磁悬浮(EMS)和超导电动(EDS)两种磁悬浮系统性能,结果表明EDS是更适合于磁悬浮助推发射的磁悬浮系统方案.通过助推发射能量需求初步分析,直线电机加速能量供给系统是难题之一,需要重点解决.采用飞行弹道分析方法,说明地面助推水平起飞单级入轨运载器方案的可行性及特点.与其它航天助推发射方式比较,磁悬浮助推发射在提高入轨载荷和降低发射成本方面具有优势.