谐振状态

The stealth warplane for the microwave radar usually have complicated structures with the coating of wave absorption. On the base of calculation and modeling of the geometrical structure of the warplane in real size, the HF RCS of the air crafts under two different polarizations in different direction have been calculated with the FDTD. The result shows that the above mentioned stealth warplane have the obvious characterstics of frequency resonance, polarization and the relatively large RCS in HF Band 10-30dBm2, which can be used as the theoretical reference for selection of working frequency for sky wave OTH Radar and it also means that the sky wave OTH radar has good capability of anti-stealth targets quantitatively.

对微波雷达具有隐身作用的飞机，其形体较为复杂且表面涂敷有强吸波材料在对一种具有隐身几何外形结构实际尺寸飞机进行计算建模的基础上，文中采用FDTD技术得到了两种极化状态下该飞机无涂敷时不同方向上的短波雷达截面RCS值其结果显示了这种隐身几何外形飞机在短波波段有明显的频率谐振特性、极化特性和较大的RCS10-30dBm2，可为天波超视距雷达在选择工作频率时提供理论参考，并定量地说明天波超视距雷达具有较优的反隐身目标能力

First, a model of transformer has been built and analysed to formulate the expression of pulse on the load capacitor, which can demonstrate the influence of major parameters of transfomer on the charging time and efficiency of energy-transmitting. The influence of output pulse when the resistor of circuit is being took into account also has been analysed by the means of circuit simulation and approximate solution of circuit equation. The efficiency of energy-transmitting under dual nonresonant condition has been analysed and the parameters of transformer has been decided.

首先，对空心变压器的理论模型进行了分析，在得到了输出脉冲电压的表达式的基础上分析了变压器各主要参数对脉冲充电时间和充电时能量传输效率的影响；同时还通过近似求解状态方程的方法对考虑线路电阻时输出脉冲受到的影响进行了分析；讨论了在非双谐振情况下的能量传输效率的问题。

A numerical simulation is performed to study the deformation and oscillation of a water drop levitated in an acoustic field.

提出了实现较大液滴声悬浮的声场条件，即将反射端-发射端间距 H 调节在略大于谐振间距 Hm 的状态。

With an output laser intensity induced negative feedback control of resonator gain, a quasi-continuous prelase with duration of ～100 μs is established, then Q-switch during this prelase .

用输出激光强度负反馈控制谐振腔的增益，建立了准连续的～ 10 0 μs宽预激光状态，然后在此预激光基础上调Q。

Prelase Q-switching method: By using output laser intensity to negatively feedback control the cavity loss, a smooth and quasi-continuous prelase of ～100μs width is built, then the cavity is Q-switched during prelase.

预激光调Q法：用输出激光强度来负反馈控制谐振腔的损耗，建立一个平坦的、准连续的～100μs宽预激光状态，然后在此预激光基础上调Q。

The existence ofpolar nanoregions dramatically influences the extrinsic dielectric nonlinearityof paraelectric phase. 5 Slow relaxations of field induced piezoelectricresonance of paraelectric barium stannate titanate were observed after eitherapplying or removing a DC bias field. This phenomenon is attributed to slowspace charge dipoles formed by injected homocharges and validated by theobservation of a negative piezoelectric constant. Isothermal study ondielectric constant and discharging current after application or removal of astep field were performed. The relaxation laws in ferroelectric andparaelectric phases are different. The transportation of homocharges arebelieved to be responsible for the strong relaxation behavior in paraelectricphase. Domain wall can trap space charges thus the relaxation in ferroelectricphase is relatively weak. Abnormal phenomena, such as slim-waisted hysteresisloops, abnormal C-V curves and clockwise reversible hysteresis loops observedin barium stannate titanate ceramics, were attributed to pinning of gatheredpoint defect on domain walls.

5研究了直流电场施加和撤除引起的钛锡酸钡顺电相场诱压电谐振慢弛豫现象，认为这是同极性空间电荷注入形成空间电荷慢偶极子导致的，观察到的负压电常数证实了这个观点；研究了等温条件下阶跃电压作用下介电常数和放电电流的慢弛豫现象，发现钛锡酸钡陶瓷的铁电相和顺电相呈现不同的宏观性能时间依赖规律，认为是同极性空间电荷的输运过程导致了顺电相样品呈现强的弛豫行为，铁电相中存在畴壁捕获空间电荷的机制因而其弛豫行为较弱；研究了钛锡酸钡陶瓷中束腰电滞回线、反常 C-V 曲线和顺时针可逆电滞回线等反常现象，将其归因于点缺陷的聚集对铁电畴畴壁的钉扎作用，多次电场循环有助于解除这种钉扎状态，减弱反常特征。

To the question of regulating the output voltage and avoiding ripple of series resonant converters, State feedback controller is designed with conversation of energy.

为了调整输出电压及解决纹波问题，本文从能量守衡的角度设计串联谐振变换器的无源性状态反馈控制器。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。