特征方程

The results achieved by the unsteady simulation on the basis of Reynolds averaged Navier-Stokes are fitted to the experiential wind profile well. The results indicate that the numerical simulation based on CFD provides a new solution to study the downburst wind characteristics under the current conditions without detailed full scale data.

数值结果表明，基于雷诺平均的Navier-Stokes方程进行的非定常数值模拟结果同根据实测数据提出的三种经验风剖面吻合良好，在目前实测资料稀少的情况下，有助于更好地研究下击暴流风的基本特征。

The method is as follows that the two ends of a nanometer are fixed on two pivots and an axial micro-pulling force T is applied on the nanometer; an electrode is arranged on the middle part of the side of the nanometer and an alternate voltage is applied on the electrode to motivate the nanometer to generate resonance, and therefore, the natural frequency f of the nanometer is measured and acquired; according to the material characteristics and the geometry characteristics of the nanometer as well as the boundary condition of the nanometer material, the relation between the natural frequency and the axial pulling force of the nanometer, namely the f-t curves of the nanometer, can be calculated by a vibration equation; according to the measured natural frequency f, the size of the micro-pulling force T can be acquired.

该方法将一根纳米材料的两端固定在两个支点上，给纳米材料施加一个轴向的微小拉力T；在纳米材料的侧面，位于该纳米材料的中部放置一个电极，在电极上施加一个交变的电压激励纳米材料使其发生共振，测得纳米材料的固有频率f；根据纳米材料的材料特性和几何特征以及纳米材料的边界条件，由振动方程计算出该纳米材料的固有频率与所受的轴向拉力的关系，即纳米材料的f-T曲线；根据上述测得的固有频率f，得到微小拉力T的大小。

Based on anisotropic elastic wave equation staggering grid high-order finite-difference numerical simulation, the wave field response characteristics of vertical fracture medium with different densities and infillings were studied.

利用各向异性弹性波方程交错网格高阶有限差分数值模拟方法，开展了不同密度和不同充填物的垂直裂隙介质的波场响应特征研究。

It was discovered that the classical transfer matrix method was inadequate for this task,and hence the larger exterior matrice s to determine the eigenfequency equation were used.

发现经典传递矩阵法已不足以解决此问题，因此采用较大的外矩阵来确定特征频率方程。

By use of the Benfield-Hurda modal synthesis method, the structural model of mistuning blade-disk assemblies is established.

用Benfield—Hurda的混合型模态综合法，给出了非谐调叶盘的特征解方程。

Through research and analysis of data, it was observed that the length and width of bark fiber varied according to the lop and age, the results show the fiber of the Salix bark is longer than the Salix and width of fiber almost same, fiber length of the Salix bark mainly influenced by the times of lop. The ash in Salix bark,1% Sodium Hydroxide Solubility in Salix bark, water solubility in Salix bark, Ethanol-Toluene in Salix bark, acid-insoluble lignin in Salix bark changed with the lop and age is also been investigated, the component of Salix bark is higher than Salix except acid-insoluble lignin,and it's high effected by times of lop; the TG analysis and DSC analysis is been used on the Salix bark and Salix to study the character of the hot-action, and the rang of the pyrogenate temperature is confirm; the quantity of Salix bark effect on the MOR, MOE, swelling in 24h water, nail withdraw and inner strength was determined, the results show that the Salix bark notability effect on the properties of board and dropped it; the properties of the Salix bark board is nearly the board product by other bark residues, it was established the multi regression equation of each properties and optimized the fitting produce condition of Salix bark board.

通过试验和数据处理，得出了沙柳树皮纤维长度、宽度随平茬和材龄的变化规律，结果表明沙柳树皮长度要比沙柳材的要长，宽度基本相同，沙柳树皮纤维长度主要受平茬次数的影响；找出了沙柳树皮中灰分、冷热水抽出物为、1%NaOH抽出物为，甲苯乙醇抽出物、酸不溶木素与平茬次数和材龄之间的关系，除酸不溶木素外，其他成分均明显高于沙柳材，沙柳树皮的化学成分主要受平茬次数的影响；利用TG和DSC法分析了沙柳树皮和沙柳材的反应热特征，确定了热解的温度范围；研究了沙柳树皮量对于刨花板MOR、MOE、吸水厚度膨胀率、握钉力以及内结合强度的影响，结果证明沙柳树皮量对于刨花板的各项性能指标影响显著，它的掺入降低了刨花板的各项性能；对沙柳树皮板的研究表明，沙柳树皮板的各项性能与同类树皮板的性能基本相近，建立的二次回归模型稳定，并利用回归方程求出了适宜的沙柳树皮板制造工艺。

With wave equation, we performed crosswell wavefield modeling. Velocity model is constructed from two sonic logs. It is readily distinguished the different characteristics of timeversusdistance for direct, upgoing, and downgoing waves on the resulted section.

利用声波方程建立井间波场数值模拟计算公式，选取一对实际井的声波测井资料建立了速度模型，进行井间数值模拟，得到了合成记录，对记录波场进行分析，能够清楚地观察到上，下行反射波和直达波的时距特征。

Solutions of a class of second-order Sylvester matrix equation and its application in the design of eigenstructure assignment are investigated.

中文摘要：考虑了二阶Sylvester矩阵方程的求解及其在特征结构配置设计中的应用。

Using numerical value test based on the wave velocity function of the transverse isotropic elastic medium, the two effects are validated.

从横观各向同性弹性介质的波速方程出发，通过具体的算例对这两种特征进行了较好的理论分析。

The variational form of the governing equations is given on the basis of the extended Hu-Washizu three-field variational principle.

基于胡海昌-Washizu三变量广义变分原理结合特征线法给出了控制方程的单元弱形式。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失