查询词典 time of vibration

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。

Strong antidumping property: When titanium is affected by mechanical vibration or electric oscillation, its vibration damping time lasts the longest time, compared to that of steel and copper.

抗阻尼性能强：金属钛受到机械振动、电振动后，与钢、铜金属相比，其自身振动衰减时间最长。

At the same time, using combination of gear and photoelectric switch for the sensors, the signal conditioning box of National Instruments Corporation and data collecting card as the main devices, the signal collecting of torsional vibration was completed. In addition, a software of the fault monitoring and analysis was developed with Visual C++. The signal real time collecting of torsional vibration and processing were realized.

同时，以齿盘和光电开关组合为传感器，NI的信号调理箱、数据采集卡等为主要器件实现了扭振信号采集；并采用Visual C++编程开发了故障监测与分析软件，实现了对扭振信号的实时采集和处理。

It's a problem desiderating solution for power industry, energy industry, aviation and shipping to real-time measure the high-speed rotating blade vibration. The conventional contacting measurement technique is difficult to measure the vibration of all blades in one stage at the same time. So foreign scholars have being applying them to research a new non-contact measurement technique using blade tip-timing.

高速旋转叶片振动实时监测技术是电力工业、能源工业、航空、航运业亟待解决的难题，传统的接触式测量方法很难做到同时监测同级的所有叶片的振动情况，因此国外一直在致力研究一种非接触式旋转叶片振动测量新技术—叶端定时测量技术。

In the fourth paragraph, how the theory of the damping to forging hammer foundation advances at home and abroad, the research and application of the implement for damping to forging hammer, the structure of damping to forging hammer and the calculation methods for forging hammer foundation vibration system, which are used at home nowadays, are particularly introduced.In the fifth paragraph, aiming at direct damping under anvil block of forging hammer, the author bases a mechanics model of two-degree with damping, and optimizes the vibration parameters both in frequency field and in time field, then finds out the new simple method of optimizing the vibration parameters of the damping device under anvil block of forging hammer.

第五章针对锻锤砧下直接支承式减振基础，建立了锻锤减振系统的二自由度有阻尼振动力学模型，然后用傅立叶变换法求出振动传递率的频率关系，用直接积分法求出砧座和基础位移的时域响应，并分别对频域函数和时域函数进行参数优化，最终建立起频率函数—时域函数—优化参数间的相互关系，从而找到了锻锤砧下隔振器参数优化的简便新方法。

The SCC has the following advantages: remarkably reducing the noisy pollution and the worker s labor intensity in construction, deducing the rough surface or segregation because of missing-vibration or excessive-vibration in conventional construction, resolving the quality-defect problems resulting from lacking-vibration in the section of complex shapes and densely-packed reinforcement area. At the same time, large of industrial solid waste such as fly ash and blast furnace slag is utilized in the proportioning of SCC. It is helpful in comprehensive utilization of resource and environment protection, so the SCC belongs to "green concrete", it is a branch of HPC which will be developed in the future.

这种混凝土可以显著降低混凝土施工中的噪音污染；大幅度减轻工人的劳动强度；减少传统混凝土施工中因漏振或过振造成的麻面或离析；解决了配筋密集、结构复杂部位因振捣不足而造成的质量缺陷问题；同时，由于自密实混凝土在配制中，大量利用粉煤灰、高炉矿渣等工业固体废弃物，有利于资源的综合利用和生态环境的保护；从而被誉为&绿色混凝土&，是未来混凝土向高性能发展的方向之一。

With the formidable data processing and programming function of MATLAB, linear superposing of one segment blasting vibration waveform, obtained from the locale vibration testing, with different time delay is carried out in this thesis, and a reasonable time delay for Jinduicheng mine bench blasting is got in the end.

本文利用MATLAB强大的数据处理编程功能，实现了对实测单段爆破振动信号在不同微差时间下的线性叠加，得到了金堆城露天矿某一爆破区域不同距离的合理微差时间。

Delay time interval effects for the time-frequency characteristic of blast vibration signal was studied aided by vibration data analyze software via matlab5.6 based on data Reassigned Smoothing Pseudo Wigner-Ville Distribution, the test data of Hainan iron corporation No.1 mining area.

基于平滑伪Wigner-Ville分布信号重排，用matlab5.6编写的振动信号处理软件，并在海钢北一采场就微差间隔时间对爆破振动的影响进行试验的基础上，研究了振动信号时频特征的微差时间效应。

Time (3Xrpm) turning table speed. In addition, while the teeth of the tri-cone bit interact with the formation, the drillstring will generate tiny axial vibration. As the vibration is symphonious to the tri-spine well bottom, the vibration signal exhibits amplitude modulation character. This character had been verified by in-site measurement data and numerical simulation.

另外，三牙轮钻头与地层作用破岩时牙轮牙齿产生啮合振动，由于三脊状井底对啮合振动进行幅度调制形成调幅信号，根据调幅信号的频率特征，振动信号在频域表现为具有一定边带的一束谱线，它是钻头工作正常的&健康信号&。

Secondly, to analyze seismic response of the concrete gravity dam, subspace iterative method was applied to compute free vibration period of the dam, time integration method was builtup for the seismic time history analysis and formulation of coupled vibration of reservoir water and dam were also deduced.

其次，针对混凝土重力坝的地震响应分析问题，采用子空间迭代法计算了大坝的自振周期，建立了地震时程分析的逐步积分方法，并且推导了库水和坝体耦合振动的理论公式。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷