自激系统

The mechanism of forced resonance and self-excited thermoacoustic oscillation are studied to understand the combustion oscillation in thermal systems.

针对热力系统中声耦合燃烧振荡问题，分析了强迫共振和热声自激两类声耦合燃烧振荡的机理，重点综述了热声自激振荡的若干驱动机制，并给出了防止声耦合燃烧振荡的措施。

The system is used to analysis the forced vibration, self-excited vibration and the propagation of disturbance in turbomachinery. Some conclusions are gained.

应用该套分析系统来分析叶片流体激振的受迫振动，自激振动和振荡流在多级叶排中传播的安全性问题，在具体应用中得到以下结论： 1。

The conditions of power system self-excitation and the influence of the automatic voltage regulator on the self-excitation are studied, and the system response characteristics of power system in the case of self-excitation are investigated.

最后，分析了电力系统自激的产生条件以及励磁调节器对自激的影响，研究了自激发生后系统的动态过程。

This thesis concentrates its attention on two problems - the stability analysis of the coordination of the relay protection and automatic devices, and the probability of self-excitation in South China Power System through time domain simulation.

本论文通过时域仿真的分析方法研究西北750kV系统保护和自动装置的配置以及南方电网复杂的长距离交直流联合输电系统"自激"这两个涉及电网稳定性的问题。

The conditions of self - excitation and the influence of automatic voltage regulator on power system self-excitation are analyzed and the system reaponse characteristics of power system under self-excitation are summarized.

分析了电力系统自激的产生条件及励磁调节器对自激的影响，研究了自激发生后系统的动态过程，提出了以发电机机端电压、发电机转子角速度以及励磁电流这3个量的变化规律作为判断复杂电力系统发生自激的依据，并以一个典型的双机系统的仿真结果验证了判据的有效性。

The dissertation studies the phenomena and characteristics of self-excitation, deduces those phenomena belong to nonlinear non-conservative autonomous steady-state periodic movement.

本文分析研究了轧机主传动系统自激振动的现象和特点，得出轧机主传动系统的自激振动现象属于非线性非保守自治系统的稳态周期运动。

Thirdly, the Hopf bifurcation of the self-excited vibration model with moving boundaries is considered.

研究了具有运动边界的自激振动模型的Hopf分叉问题，从系统自激振动的极限环生成和消亡的过程可发现：系统在边界的运动速率变化时能够发生一阶超临界Hopf分叉。

Resultantly, the individual warm/cold events in ENSO cycle appear to be partially locked to the annual cycle, and also exhibit obvious irregularity both in amplitude and in lasting time.

本文第四章研制设计了一包含海洋表面边界层和大气辐合反馈过程的热带太平洋海气耦合异常模式，进而利用该模式对ENSO循环进行了较为真实的模拟，通过对模式ENSO循环的演变特征及其形成机制的细致分析，建立了-ENSO循环的非线性分析模式，并提出了ENSO循环形成的一种更为客观的理论，指出：1）和观测事实类似，模式ENSO循环确实涉及了三种主要时间尺度过程即LF、QB和AC，其中LF为3-4年主周期振荡，QB占总方差10～20%；2）ENSO循环的正反馈机制是不稳定海气相互作用过程，且这一不稳定过程的发展在暖态中明显强于冷态；3）ENSO循环的负反馈机制在冷暖态中表现不同，在冷态消亡过程中，这种负反馈过程主要表现为西边界反射产生的时滞效应，但在暖态消亡过程中不存在类似的时滞效应，其负反馈过程主要表现为在海气耦合不稳定充分发展时伴随的赤道两侧冷水上翻过程的加强以及非线性过程的衰减作用抑制了不稳定的发展并最终使得系统回复至冷态；4）ENSO循环的3-4年主周期振荡是一非线性系统的自激振荡现象，其形成是线性系统的本征模即准两年振荡通过非线性机制产生的周期加倍所致，其中&单向性&大气辐合反馈加热过程对其形成至关重要；5）虽然年循环过程对ENSO循环形成没有本质影响，但它可明显影响ENSO循环的具体振幅和位相，使得ENSO对季节循环有明显的&锁相&特征，并且也使得ENSO循环在振幅大小和时间长短方面呈现出明显的不规则性。

This method use positive feedback control to let torsion bar self-excitation, then by measuring torsion pendulum system's nature frequency to calculate torsion bar's stiffness.

针对扭杆刚度的测量，提出了一种全新的动态测量方法─—自激动力微摆法：该方法采用正反馈使扭杆自激，通过测量扭杆扭摆系统的固有频率来计算扭杆的刚度。

Description: This project shall adopt the double-mixing-shaft reciprocal rotary distribution design, with the vibration excitation/isolation system to be floating-connected by double-seated spring and hydraulic system adopting highly-dynamic performance proportion, making unnecessary a separate motor for driving and ensuring high compactness of blocks. The machine should make less noise than similar products, operate quickly, reduce the impact upon change of direction and save energy. Each joint should be linked with knuckle bearing and provided with lubricating device to prevent wear and tear. The automatic control system should use PLC and HMI display of operation, providing accurate and explicit detection of faults.

内容说明：本项目采用双搅拌轴往复旋转布料设计，激振隔振系统采用双座双弹簧浮动连接，液压系统采用高动态性能比例，可使砌块成型机不需要单独电机驱动，能保证砌块密实度大；机台噪声比同类机台小，运行快速，降低变向时的冲击配备，节约能源；各关节部位均用关节轴承联结，具备润滑装置不易磨损；自控制系统选用PLC编制控制器，操作人机界面显示，故障准确明确。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。