模态

Finally, we analyzed the relationship between the defect modes and s defect structures. The defect mode is most obvious where the defect structure is located. This confirms the relation between the defect mode and defect structure.

最后，我们分析了光子晶体缺陷模态与缺陷结构的关系，发现缺陷模态在缺陷结构处最为明显，证实在频谱中观测到的缺陷模态，确实与所制作的缺陷结构有关。

By using the modal superposition method for the dynamic responses calculation of the linear oscillation system, a judging indictor in the energy norm form is given to determine the number of dominant modes on mode truncation .

针对用模态叠加法计算结构线性振动系统的响应，作模态截断的截尾模态阶数的取值，给出了能量范数形式的判断指标。

Since the modes of foundation are dense,by taking the criterion of energy response as mode truncation index,the energy norm and criterion are established to calculate the mode truncated order of dynamic compaction response.

由于地基模态密集，提出以能量响应信息的收敛作为模态截断的判断指标，建立能量范数和能量判据，计算强夯动力响应的模态截断阶数。

When the residual modes are high frequency modes, it will be suitable to use a filter to prevent the spillover by filtering the measuring signals. The closed loop poles would excurse if the measuring signals were filtered directly.

对于剩余模态和控制模态分离得较好的受控对象，可采用对测量信号进行滤波去除信号中剩余模态分量的方法防止溢出问题。

With simplified assumption made for the modal trial mass ratio and the linear response characteristic of the holobalancing technique, the transfer matrix corresponding to a certain correction plane then is extended to the trial set transfer matrix, which is related to a certain order of modal trial mass set. The number of trial runs necessary for the balancing operation is reduced and the balancing efficiency is improved.

借鉴Darlow混合法中模态试重组的思想，通过对模态试重比的简化假设，利用迁移矩阵的线性可叠加性将对应于某单一平衡面的迁移矩阵扩展为对应于某阶模态试重组的迁移矩阵，从而减少了平衡高阶不平衡量所需的试重起车次数，提高了现场平衡效率，且平衡效果良好。

With simplified assumption made for the modal trial mass ratio and the linear response char acteristic of the holobalancing technique, the transfer matrix corresponding to a certain correction plane then is extended to the trial set transfer matrix, which is related to a certain order of modal trial mass set. The number of trial runs necessary for the balancing operation is reduced and the balancing efficiency is improved.

借鉴Darlow混合法中模态试重组的思想，通过对模态试重比的简化假设，利用迁移矩阵的线性可叠加性将对应于某单一平衡面的迁移矩阵扩展为对应于某阶模态试重组的迁移矩阵，从而减少了平衡高阶不平衡量所需的试重起车次数，提高了现场平衡效率，且平衡效果良好。

Finally, based on the characteristics of transient responses and the Morlet wavelet, a family of wavelet functions is introduced and used in the simulation of modal analysis.

文中分析了在众多小波基函数中Morlet小波更适合对动态结构系统进行模态分析的原因，结合Morlet小波的性质和结构系统对脉冲响应信号的特性，构造了一小波族，实现了利用Morlet小波变换对多自由度系统进行模态解耦和对时变系统进行模态参数辨识的方法。

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。

The results show that whether the stiffness profiles are smoothly varying or layered, the fundamental mode dominates the surface wave field and the effective phase velocity approaches to the phase velocity of the mode in far field for the regular profiles. For the irregular profiles, the higher modes have a significant influence on the surface wave field. The intensity and the frequency range of the influence are related to variation of the profile stiffness.

结果显示，无论剖面刚度是缓变还是分层变化，对规则剖面，表面波场基阶模态占主导地位，远场表面波有效相速度与基阶模态相速度接近；对不规则剖面，表面波场中高阶模态影响较大，影响程度及频率范围与剖面刚度变化有关。

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％。