| 1. | By using a saturated feedback control structure , the control law is obtained by solving a linear matrix inequality ( lmi ) optimization problem on - line
初始时刻优化问题的可行性保证了闭环控制系统的鲁棒稳定性。 |
| 2. | The results are that the maximum displacement and maximum stress occurs at initial time and the maximum stress is less than permissible stress
结果表明,结构最大应力和最大位移均发生在初始时刻,最大应力小于许用应力。 |
| 3. | The accuracy of modern numerical prediction mainly depends on the exact model that can simulate the synoptic course and the initial field that can describe the initial time
现今数值预报的准确程度主要依赖于能够描述天气过程的精确模式和能够反映初始时刻的准确初始场。 |
| 4. | The employment of such a technique iv appears necessary because the traditional linear design process cannot incorporate the nonlinear dynamics of such system and its physical limitations
该方法使得倒立摆系统从初始时刻开始就运行在滑模面上，从而使系统具有较强的鲁棒性，取得了非常好的实验效果 |
| 5. | In light of the limitation of fast fourier transform ( fft ) for the method of traditional spectrum analysis to analyze the unsteady signal , wavelet and wavelet analysis are made for the typical unsteady process signal of starting up and shut down with the good characteristic of simultaneous localization in both the time and the frequency domains based on the field test on the vibration of two - row placed units in lijiaxia hydropower station , in which the signal is decomposed into different frequency band , and then the weak signal is caught and the dominant frequency is picked up for the analysis of the vibration source
摘要基于李家峡水电站双排机组振动的现场试验研究，并且针对传统频谱分析方法傅立叶变换( fft )对于非平稳信号已力不从心这一缺陷，利用小波分析方法在时域和频域上同时具有良好的局部化性质，通过对开停机这一典型非平稳过程信号进行小波及小波包分析，将其分解到不同频带内，获取微弱信息和提取优势频率，并对其作振源分析，得出开停机初始时刻因水流不稳均出现强烈的振动现象，且低频段信号能量最大，开停机过程水流脉动压力和尾水涡带摆动是引起定子基础振动的主要原因。 |
| 6. | Under an appropriate condition , the squeezed vacuum field can trap the two atoms in ri ) . an analytical expression of emission spectrum for three - level atom interacted with two - mode cavity field is given . the effects of the initial state of system on the emission spectrum for three - level atom are explored
我们给出了好腔中与双模腔场相互作用的三能级原子发射谱的一般表达式，探讨了系统初态对三能级原子发射谱的影响，阐明了只有原子和双模驱动场初始时刻均处于相干叠加态，原子不同跃迁通道间的量子干涉才使得原子发射谱呈现相位敏感性。 |
| 7. | The assimilation experimentation results indicate that after assimilating radar wind field of small spatial scale , mesoscale and small - scale precipitation prediction can be improved and mesoscale and small - scale information which ca n ' t appear by tradition datum can be gained , which is valuable to analyze the mesoscale and small - scale system structure ; the effect assimilating radar humidity field is n ' t obvious , which is perhaps correlation with precipitation types and assimilating time . the results also show that adding radar humidity field to initial condition at initial time can supply the gap of the regular data in reflecting the mesoscale and small - scale systems , strengthen the humidity in the initial field , and eventually help to improve precipitation . the experiment of assimilating radar wind field and radar humility field at the same time shows that vapor transportation and local vapor divergence play more significant role in causing excessively heavy rain than only high wet center
同化试验结果表明：同化空间分辨率很高的雷达风场后，能改善中小尺度降水的预报效果，并且能够得到常规观测资料所不能得到的中小尺度信息，对分析中小尺度系统结构具有重要意义；同化雷达湿度场效果不明显，可能与降水类型和同化时刻有关；而直接在初始时刻加入雷达湿度场，补充了常规资料在反映中小尺度系统方面的不足，增强了初始场中的水汽，有利于降水量的增加；同时同化雷达风场和雷达湿度场的试验表明，水汽的输送和局地的水汽辐合对于产生特大暴雨的贡献远大于仅有高湿中心的贡献。 |
| 8. | At the preliminary stage of burning the gas flows along the back surface of the submerged nozzle and no recirculation forms in the aft - end cavity . at the medium stage of burning a weak recirculation forms in the rear of aft - end cavity by the force of injection flow . at the end stage of burning the flow separates at the c ombustion channel and a strong vortex forms in the aft - end cavity
实验结果表明，在发动机工作过程中随着燃面的退移，燃烧室尾部的流动会发生很大变化，初始时刻背壁区加质流沿喷管背壁进入喷管，背壁区没有回流形成；中间时刻在加质流的驱动下背壁区后部形成较弱的回流；结束时刻气流在燃烧室壁面分离，背壁区形成强烈的回流。 |
| 9. | In chapter four the effects of a static electric field and different initial states on hhg are studied . under an additional electric field the spectrum exhibits a double - plateau structure . furthermore , the ionization probability and hhg also behave differently when the hydrogen atom is in different initial states
在第四章中，我们研究了外加平行静电场以及初态的不同对电离率和高次谐波的影响，发现附加一适当的静电场会使谐波曲线呈现一双平台结构，电离率会随着电场强度的增大而增大；当氢原子在初始时刻处于不同态时，根据选择定则，谐波曲线和电离率都会有较大差别。 |
| 10. | When the cavity field is initially in photon number state or mixed state , the emission spectrum of the two - level atom has nothing to do with the phase of the atomic dipole . if the cavity field is initially in the coherent superposition of photon number state , the emission spectrum of the two - level atom exhibits phase sensitivity . if a a - type three - level atom is initially in the coherent superposition of its two non - degenerate lower states , the emission spectrum depends on the phase of the atomic dipole
证明了初始时刻驱动场处于光子数态或者光子数的混合态时，二能级原子发射谱与原子偶极矩的相位无关，只有当驱动场初始时刻处于光子数的叠加态时，原子发射谱才依赖于原子偶极矩的相位；而初始时刻处于两个下能态相干叠加态的型三能级原子发射谱对原子初态的依赖关系却不受单模驱动场的影响。 |
