查询词典 damping-off

The microstructure of ferromagnetics for Fe-Al alloys as well as the effects of alloy elements and heat treatment on the damping behavior and mechanical properties of Fe-Al based alloys have been investigated systematically by means of optical microscopy,scanning electron microscopy.

采用光学显微和扫描电子显微观察等方法，系统地研究了Fe-Al系铁磁性阻尼合金的微观组织，考察了合金元素、热处理工艺对合金阻尼性能和力学性能的影响，探讨了Fe-Al合金产生高阻尼特性的微观机制以及Fe-Al系高阻尼合金的同质和异质焊接性能。

By combining the interval mathematics and the finite element analysis, the mass matrix, damping matrix, stiffness matrix and the external loads are represented as interval matrices and vector.

通过结合区间数学和有限元分析，结构质量矩阵、阻尼矩阵、刚度矩阵和外载荷列向量采用区间矩阵和区间向量来描述。

For some shortcomings of unknown quantity numbers in finite element method, QR-method establishes a transformed relationship between a unit node displacement vector and the entire framework of spline node displacement vector,making the structure of the total stiffness matrix, damping matrix, mass matrix directly superimposed in no need of finite element method in the first expansion after the superposition process. So the method greatly simplifies the calculation process and improves computing speed.

针对有限单元法中未知量数目很多的缺点，QR法建立起单元结点位移向量与整个框架样条结点位移向量的转化关系，使得结构总刚度矩阵、阻尼矩阵、质量矩阵可以直接叠加，不需要有限单元法中先扩张后叠加的手续，大大简化了计算过程，提高计算速度。

The modal tests of PCB and PCB assembly (free boundary condition and fixed boundary condition) were carried out. The equivalent elastic modulus and damping parameters of PCB can be gained, and the fixed boundary condition of finite element model was also determined. These will help to the following work.Second, drop impact tests of three different heights were carried out. Strains and acceleration responses of PCB were measured. Failed BGA packages of different test conditions were dyeing, and cross section analysis of failed solder joints was conducted.

针对JEDEC标准试件的局限性，提出了设计便于统计学研究焊点可靠性的试验试件的构想，利用有限元模态分析方法确定并验证了用圆形PCB组件替代JEDEC标准试件的可行性；通过一系列模态试验和有限元模态分析，确定了圆形PCB组件的相关试验参数，这不仅为跌落碰撞下PCB组件有限元模拟确定了较为合理准确的有限元模型，而且为正确地评价跌落碰撞下PCB组件的可靠性问题奠定了基础。2。

The modal tests of PCB and PCB assembly (free boundary condition and fixed boundary condition) were carried out. The equivalent elastic modulus and damping parameters of PCB can be gained, and the fixed boundary condition of finite element model was also determined. These will help to the following work. Second, drop impact tests of three different heights were carried out. Strains and acceleration responses of PCB were measured. Failed BGA packages of different test conditions were dyeing, and cross section analysis of failed solder joints was conducted. It was found in our drop tests that the root cause of lead-free solder joints under drop impact was the combined effect of mechanical shock and PCB bending vibration.

针对JEDEC标准试件的局限性，提出了设计便于统计学研究焊点可靠性的试验试件的构想，利用有限元模态分析方法确定并验证了用圆形PCB组件替代JEDEC标准试件的可行性；通过一系列模态试验和有限元模态分析，确定了圆形PCB组件的相关试验参数，这不仅为跌落碰撞下PCB组件有限元模拟确定了较为合理准确的有限元模型，而且为正确地评价跌落碰撞下PCB组件的可靠性问题奠定了基础。

Damping Adjust - External rebound, low speed compression to 'Lock' with external Floodgate

阻尼调整-外部反弹，低速压缩'锁'与外部闸门

The forces and moment for the model advancing forward with forced heave and forced pitch oscillation, and the hydrodynamic mass and damping coefficients for heave and pitch motion of the model are given. The results of numerical simulation are compared with the experimental data from Delft University of Technology, and show good agreement with them.

文中给出了以不同航速前进的船舶强制垂荡和纵摇的力与力矩，以及船舶垂荡和纵摇的附加质量系数和阻尼系数，并与DUT的试验数据进行了比较，二者吻合良好。

At first, based on the results of the field tests and studies, this paper indicates that there are two kinds of low frequency power oscillations on the weak tie line: one is caused by negative damping, and belongs to the free oscillation; the other is caused by periodic load disturbances and periodic adjustments, and belongs to the forced oscillation.

首先，本文根据现场试验和研究结果指出，互联系统的弱联络线上存在两类性质不同的低频功率振荡：一类是由负阻尼引起的，属于自由振荡；另一类是由于系统周期性负荷扰动或振荡调节等引起的，属于强迫振荡。

Therefore, the study for material damping of RC and CFST under forced vibration is urgent in theory and practice of seismic design and dynamic analysis of structures.

因此，钢筋混凝土和钢管混凝土受迫振动条件下的材料阻尼研究对工程结构抗震设计与动力分析具有重要的理论与实际意义。

It is showed in plenty of research papers that under forced vibration, damping value is far more than that obtained in free vibration test and increases with the increase of stress or deformation.

大量的研究和测试资料表明，在强迫振动作用下，阻尼要比由自由振动测试所获得的数值大出很多，是随着应力或变形的增大而提高的。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。