振荡

The theory of accretion disks are important for many astrophysical phenomena, including Quasars, active galatic nucleic, X-ray binary stars, and young stellar objects. The most important branch of accretion djsk theory is the stability properties of djsks. It is widely considered that the luminosity variations of various astronomical objects are associated with the instability of accretion disk. The viscosity plays an important role in the accretion disk theory, and magnetic field exists commonly in astronomical phenomena. A more realistic analysis of the stabihty of the accretion disk should include both the radjal and azimuthal perturbations because of the strong shear of viscous flow.In this paper, according to the luminosity Variations of Various astronomical objects, we study the radial-azimuthal instability of an isothermal with magnetic field. We find that the radial and azimuthal fields B〓,B〓 are mainly responsible for enhancing the instability of the magneto-acoustic modes and non-axisymmetric modes,and that pulsational oscillations are larger in the radial than in the Z direction. The model may be useful in explaining the periodic light variation of FU orionis and. T Tauri stars.

在许多天体物理现象中，例如活动星系核，X-射线双星和年青的恒星理论中，吸积盘理论起着重要的作用，而吸积盘理论中的一个重要分支是吸积盘的不稳定性理论，普遍认为活动天体的周期，准周期光变现象与吸积盘的不稳定性有关，在吸积盘理论中，粘滞起着重要的作用，而磁场是天体物理中普遍存在的现象，对于几何薄吸积盘不稳定性分析，由于强剪切流的缘故，应该包括径向和环向扰动两个方面，本文结合天体物理中的各种周期，准周期光变现象，研究了含磁场的等温薄吸积盘的径向-环向振荡不稳定性，结果表明：磁场的径向和环向分量对磁声模和非轴对称模的不稳定性的增加起着主要的作用，且径向振荡大于轴向振荡，所得结果有利于解释FU Orionis和T Tauri Stars的周期光变现象。

In order to look for fast calculation model of a linear oscillation motor, which can express the transitive relation between parameters and performance. The basic mathematic model of a linear oscillation motor is established by finite analysis method and the regression modeling method for the support vector machines is introduced. Then, the SVM calculation model is set up. A shortcut online calculation method is provided for the process of the parameter optimization of linear motors.

为了寻找反映直线振荡电机参数与性能输入输出传递关系的快速计算模型，利用有限元分析法，建立了直线振荡电机非参数建模的基本数据计算模型，根据基本数据计算模型，引入支持向量机(Support Vector Machines， SVM)非参数回归建模方法，建立了用于直线振荡电机参数与性能之间输入输出传递关系的SVM计算模型，为电机参数优化过程提供了方便快捷的在线计算方法。

The resultant audible frequency when two sources of unequal undamped electrical oscillations of constant amplitude act simultaneously in the same circuit.

振幅为常量的非平衡无衰减电子振荡的两个振荡源在同一电路中同步振荡时产生的音频。

In the same neuron, veratridine (1.5～5.0 μmol/L) caused slow wave oscillations of interspike intervals, while aconitine (10～200 μmol/L) caused tonic firing.

结果发现，在同一神经元，藜芦碱(1.5～5.0 μmol/L)可以引起放电峰峰间期的慢波振荡，即峰峰间期由大逐渐减小，然后又逐渐增大，形成重复的振荡波形，每个振荡持续约数十秒至数分钟；而乌头碱(10～200 μmol/L)则引起强直性放电，即峰峰间期逐渐减小，然后维持在一个稳定的水平。

The Mn(superscript 2+)-BrO(superscript - subscript 3)-H(superscript +)-Act oscillating systems of Chinese traditional medicine compounds (Siwu Decoction and Windflower Decoction) are studied at different concentrations and different temperatures by TAM Air 8-channel calorimeter.

用微量量热法对中药复方四物汤和白头翁汤的Mn(上标 2+)-BrO3-H-Act振荡体系进行了研究，得到了四物汤和白头翁汤分别在不同浓度、不同温度下的振荡谱图和310K时体系发生振荡的浓度范围。

The Mn~(2+)-BrO~-_3-H~+-Act oscillating systems of Chinese traditional medicine compounds(Siwu Decoction and Windflower Decoction ) are studied at different concentrations and different temperatures by TAM Air 8-channel calorimeter.

用微量量热法对中药复方四物汤和白头翁汤的Mn2+-BrO3--H+-Act振荡体系进行了研究，得到了四物汤和白头翁汤分别在不同浓度、不同温度下的振荡谱图和310 K时体系发生振荡的浓度范围。

NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI, 10 μmol/L), abolished histamine-stimulated calcium oscillations both in normoxic and posthypoxic PAECs.(3) Xanthine oxidase inhibitor, oxypurinol (100 μmol/L), did not affect the calcium oscillation kequency in normoxic PAECs. However, it significantly decreased the elevation of calcium oscillation frequency in posthypoxic PAECs.

黄嘌呤氧化酶抑制剂，别嘌呤醇(oxypurinol，100 μmol/L)能显著降低组胺刺激的缺氧后肺动脉内皮细胞升高的钙振荡频率，但降低后的钙振荡频率仍高于常氧组，别嘌呤醇对组胺刺激的常氧组肺动脉内皮细胞钙振荡频率无显著影响。

NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI, 10μmol/L), abolished histamine-stimulated calcium oscillations both in normoxic and posthypoxic PAECs.(3) Xanthine oxidase inhibitor, oxypurinol (100μmol/L), did not affect the calcium oscillation frequency in normoxic PAECs. However, it significantly decreased the elevation of calcium oscillation frequency in posthypoxic PAECs.

黄嘌呤氧化酶抑制剂，别嘌呤醇(oxypurinol， 100μmol/L)能显著降低组胺刺激的缺氧后肺动脉内皮细胞升高的钙振荡频率，但降低后的钙振荡频率仍高于常氧组，别嘌呤醇对组胺刺激的常氧组肺动脉内皮细胞钙振荡频率无显著影响。

By applying electromagnetic vibration on solidification front of Sn-10Pb alloy,creation of equiaxed grain zone in ...

在低强度电磁振荡条件下，凝固组织细化和等轴晶化的原因是：电磁振荡力对金属初生晶的周期性拉伸、压缩、剪切、折弯、扭转等机械作用，使其出现断裂和剥落，增加形核数量；电磁振荡的局部搅拌作用使固/液界面前沿的温度和成分趋于均匀化，导致梯度降低，抑制了柱状晶的生长。

But in practical operating, overvoltage caused by reignition of the vacuum switching device frequently appears, and it result in damage of the capacitor bank or the switchgear itself. Ensuring the switchgear against reignition and installing a protective device are two main approaches to avoid the phenomenon. In this paper, a study on overvoltage caused by reignition due to capacitor bank switching with the vacuum switching device and its preventive measures are carried out. The main work which has been done and researches are as follows: 1. The producing mechanism of overvoltage and its influence factor are analyzed. It is pointed out that single-phase reignition is the main reason for damage of the switchgear and two-phase reignition is the main reason for damage of the capacitor bank,so overvoltage of single-phase reignition and two-phase reignition are the emphases of prevention. 2. Analysis of the special working condition of the operating switch for capacitor bank is carried out. It indicates that the vacuum switching device is difficult to realize no-reignition under this operation condition, so it is more practical to adopt protection devices. 3. Analyses of protection effect of RC and MOA and their shortages are carried out. It shows that the two methods can only restrain effectively overvoltage caused by single-phase reignition, and they cannot protect the capacitor bank when reignition of two-phase occurs. 4. The operation principle of G-R damping device is analyzed and discussed emphatically.

本文针对真空开关投切电容器组时因重燃而产生的过电压及其防治措施进行了研究，所开展的主要工作和研究结果如下： 1、对过电压的产生机理及其影响因素进行了分析，指出单相重燃是导致开关设备损坏的主要原因，而两相重燃则是导致电容器组损坏的主要原因，因此单相重燃和两相重燃过电压是防护的重点； 2、对电容器组操作开关的特殊运行条件进行了分析，指出在这种运行条件真空开关难于实现不重燃，因此采用保护装置更具有现实意义； 3、对RC与MOA的保护效果和存在的不足进行了分析，指出这两种方法均只能有效抑制单相重燃过电压，而不能在发生两相重燃时保护电容器组； 4、重点对G-R阻尼装置的工作原理进行了分析和讨论，指出该装置接入后线路中将会出现两种频率的高频振荡，而电容器组上的过电压是由这两种振荡共同决定的； 5、根据对上述两种振荡的分析指出存在一个最佳电阻值使得过电压最低，并提出了电容器组电压和最佳电阻值的近似求解方法； 6、使用电气暂态分析软件MATLAB对G-R装置的保护效果进行了仿真计算，证实该装置确实可以有效抑制重燃时的电容器组过电压； 7、根据仿真与近似计算结果的偏差提出了近似计算的修正方法，经过修正后的过电压计算结果与仿真结果吻合较好； 8、对G-R装置中放电装置G与阻尼电阻R的要求进行了分析，指出采用编织电阻和真空间隙可能是最佳选择。

I am sure after a few weeks of adaptation and familiarization I will have no difficulty in functioning on a daily basis in an English speaking society or in participating fully in graduate studies.

在大学的三年的学习生活不仅给予我自身的充实，更重要的是磨练和培养了我较强的自觉能力和严谨，踏实的作风以及不怕困难的精神，对未来充满了信心！

As the first volcanoes erupted, one of the gases that bellowed out was steam.

在第一批火山喷发时，喷出的气体之一就是水蒸汽。