查询词典 oscillation method

However, based upon the results indicated above the heat transfer rates with certain combinations of the oscillation amplitude and Rayleigh number or Grashof number are possibly smaller than that of the stationary condition. Then the critical oscillation frequency could be regarded as a criterion of whether the heat transfer rate of the heat surface subject to a oscillation motion being larger than that of the stationary state or not .

虽然一般的观念大都认为存在振动的热表面其热传的效果会比没有振动的情形下要好，但是由研究结果得知，在不同的振幅与雷利数或葛瑞秀夫数搭配时，加入振动后的热传现象仍可能比没有振动时的热传效率差，也因此可以定义且找出临界振动频率以提供研究振动热传者之参考。

Secondly, it is concluded that all these researches above supported the conclusion that the thermoacousitic oscillation in combustor is the self-excited oscillation with feedback that produced the limit cycle oscillation with stable amplitude.

最后将其扩展到多旋流预混燃烧，试验比较了不同组分模拟合成气在三种多旋流模型燃烧室中进行预混燃烧的不稳定燃烧特性。

Main contents are as follows :In chapter one, we give a survey to the development and current state of the oscillation of differential equations and difference equations. We also introduce some preliminary material , including some basic concepts of the oscillation theory and some important fixed point theorems.In chapter two, we investigate the oscillation of second order self-conjugate differential equation with impulses.

本文由五章组成，主要内容如下：第一章概述了微分方程及差分方程的应用背景和国内、外研究状况，这一章也包括一些预备知识，如有关微分方程、差分方程理论的基本概念和重要的不动点定理。

In this paper Ⅰ successfully applied these methods to fault diagnosis, and presenting some new innovative machinery fault diagnosis method; First Ⅰ present a new gear wornout fault diagnosis method, this method use the vibration signal's time-frequency attribute and instantaneous phase undulation to accurately detect gear's fault, and by comparing with the traditional frequency domain analysis method, this method reveals that many nonlinear and nonstationary characteristic exist in gear's vibration, this tell us that if we use frequency domain analysis method without pay attention to the signal's characteristic, we could get wrong diagnostic result; Then Ⅰ present a new bearing fault diagnosis method, this method use ATVFD and Hilbert transform to do envelop demodulation,Ⅰ analyze the envelop with time-frequency method and find out that this method is more accurate then traditional method.Ⅰ also explain that the modulation of the fault to the carrier wave may also be non-stationary and nonlinear; Finally Ⅰ present a cylinder pressure measurement method of diesel engine by means of vibration, cylinder pressure is an important parameter of diesel engine fault diagnosis, the pressure measuring is simplified a lot by this method,Ⅰ also use the ATVFD and time-frequency analysis to realize it.

本文中将上述理论方法成功地应用到故障诊断中去，提出了几点创新性的诊断方法；提出了一种齿轮磨损故障诊断的新方法，该方法利用振动信号能量的时频域分布特征与瞬时相位波动特征可以进行精确的齿轮故障诊断，并通过与传统的频域诊断方法的比较，揭示出齿轮振动中存在的明显的非线性与非平稳特征，说明了不加选择地利用频域分析方法进行齿轮故障诊断很可能会得到错误的诊断结果；提出了一种轴承故障诊断的新方法，该方法利用ATVFD分解与Hilbert变换进行包络解调，并对解调得到的包络信号进行时频域分析，可以实现更加准确轴承故障诊断，说明了故障对载波信号的调制往往也是非平稳与非线性的；提出了一种利用振动信号进行柴油机汽缸内压力检测的新方法，柴油机汽缸压力的变化是柴油机故障诊断的重要参数，利用振动方法可大大简化汽缸压力的检测过程，该方法也是综合利用ATVFD分解与时频域分析方法实现的。

This train classifies "information carrier adhering to the build" as design elements, and probes into integrated design method of it and single building separately: method of definite position, method of definite form and method of combination; Then, this train probes into integrated design method of it and colonys building , that bases on the cognitive design method: method of rhythm controls,method of node outstanding, and that aims at the design method to protect: method of protect original, method of repairing and method of renewal.

本文的第四部分提出了一体化设计的思路，将建筑附着信息载体作为设计元素，探讨了它与建筑单体一体化设计的方法：定位法、定形法、混合法；以及它与建筑群体一体化设计时，基于认知的设计方法：节奏控制法、节点突出法，旨在保护的设计方法：存真法、修缮法、更新法。

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。

It can be seen that the traditional sub-oscillation control method is just a special case with zero gain of source voltage in method based on MPAM, which brings the control concept of sub-oscillation method clear.

研究还表明，传统的三角波比较方法是基于MPAM控制方式在电源电压的放大系数为0时的一种特例，从而使得三角波比较法的物理概念清晰化。

Based on description method of damping motion in mechanical vibration, variables movement of generator are divided into two basic motion models: damping oscillation and critical damping motion. Detail methods of extracting damping parameters from simulation data is introduced to establish variable motion models. An approximate method is put forward to simulate low-frequency signal and generator response characteristic, from which motion models and damping parameters of main variables are obtained. The influences of oscillation amplitude, frequency and initial operating point of power system to the motion damping parameters are analyzed.

借鉴机械振动中阻尼运动的描述方法，将低频振荡下发电机主要变量的运动归纳为阻尼振荡和临界阻尼两种基本运动形态；介绍了从仿真数据提取阻尼参数建立参数运动模型的方法，实现对发电机振荡特性的量化分析；提出一种系统侧低频振荡信号的近似模拟方法，并应用于发电机响应仿真，获得了主要变量的运动模型和阻尼参数；分析了系统侧振荡幅度、频率以及初始工况对发电机功角振荡的影响。

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

The revised Hargraves formula has the best result compared with Penman-Monteith formula, the average relative error is 6%, moreover, Hargaves method requiring the least data in calculating ETo, so this method has the high actual application value; The following are Radiation method and Blaney-Criddle method ; The worst is the Pan method, even after revised, the highest and average relative error is 36% and 10%, respectively. So, in this study, Penman-Monteith method, Radiation method, Blaney-Criddle method and Hargraves method are used except Pan method.

在这四种方法中，修正后的Hargraves方法与彭曼—蒙特斯方法的计算结果符合最好，其平均相对误差为6％，而Hargraves方法需要的气象数据只有计算时段的最高、最低温度，该方法具有较高的实际应用价值；辐射方法和布兰尼—克里德尔方法次之；蒸发皿方法最差，即使在修正后，E601型蒸发皿的最大误差也高达36％，平均为10％，所以在预报系统的研究设计中采用了除蒸发皿方法之外的四种方法。

Now he worked in ajoint venture.

现在他在一家合资企业工作。

More troops in Afghanistan won't change any of the foregoing.

更多的在阿富汗的军队也不会改变之前的状况。