查询词典 sound velocity

According to the studied results at present, the studied objects are mainly thin plate and beam about sound radiation mode, a method computed sound radiation mode of complex structure is presented in this dissertation, according to the results of the previous two chapter, a theoretical method to solve acoustical radiation mode and acoustical radiation efficiency of complex structure by boundary element method and acoustical radiation theory is posed, the acoustical radiation power is expressed as a Hermitian quadratic form, while the radiation modes is determined by general eigenvalue decomposing, and then the radiation efficiency is computed via the orthodoxy of radiation modes with regard to impedance matrix and average velocity matrix; lastly, the validity of the method is proved by pulsating sphere and radiating cube with analytical results. According to results of the form three chapter, the structure sound radiation sensitivity is studied in detail, the sound radiation power of structure can be expressed as positive Hermitian quadratic form, the sound radiation sensitivity can be expressed as two parts by partial differential with respect to design variable, which are sensitivity of boundary velocity and impedance matrix, combined with the theory of FEM and BEM, the structure sound radiation can be translated to the analysis of structure dynamic sensitivity and impedance matrix sensitivity. The theory posted in this dissertation is tested by the FEM software ANSYS and the software AAS programmed by author.

在前几章的基础上，通过结构声辐射的模态理论对结构的声辐射的机理进行了深入地探讨，针对目前声辐射模态的研究对象主要是简单的板和梁类结构，提出了一种计算复杂结构声辐射模态的方法，利用前两章研究所得的结论，将边界元方法与广义特征值的理论结合起来研究了复杂结构的声辐射模态与声辐射效率，先将结构的声辐射功率表示为一个正定的厄米特二(来源：ABb7C论文0909网www.abclunwen.com)次型，运用广义特征值分解求解了复杂结构的声辐射模态，然后利用声辐射模态关于阻抗矩阵与均方速度耦合矩阵的正交性，求解了复杂结构的声辐射效率，最后用具有解析解的脉动球与辐射立方体验证了该方法的有效性。

The minimum fluidization velocity has a minimum value when the frequency of sound waves is 120Hz and it will decrease as the sound pressure level increases. The degree of sound attenuation will increase while bed material is higher and the fluidization quality of fine particles will become poor and the minimum fluidization velocity will increase. Compared with TiO2, the SiO2 fine particles have a better quality of fluidization at the same fluidized conditions.The cluster/subcluster model and oscillators model are used to describe the fluidization characteristics of fine particles in a sound-assisted fluidized bed. The theoretical calculations show that the minimum fluidization velocity umf is decreased with the SPL increased at the same frequency of sound and the quality of fluidization is better.

论文还系统的考察了声压和频率对纳米SiO2和TiO2颗粒流化特性的影响，结果表明：在频率一定的情况下，声压越高，流化床中形成的聚团尺寸越小，最小流化速度越低，流化质量越好；当声压低于120dB时，声场对超细颗粒流化特性的影响减小，当声压大于130dB时，则能显著改善流化效果，使流化床内的颗粒聚团明显减小，最小流化速度明显降低，粉体带出减小；声压一定，频率为120Hz左右时，最小流化速度最低，此时流化床中形成的聚团尺寸最小，流化效果最好；超细颗粒达到较好的流化状态存在一个最佳频率范围，随着声压增高，这个频率范围将增大。

In this thesis, the crystal structure and phase transition behaviors of a andβforsterite (Mg2SiO4) at high temperature and high pressure were investigated by the first principle calculations and the quasi-harmonic Debye model. Variations of elastic properties, band structure, density of state, band gap ofαandβforsterite with pressure were calculated, and the effect ofα/βphase transition on these characters was analyzed. The effects of water on elastic modulus, sound velocity and band gap of forsterite were also simulated. Finally, the effect ofα/βphase transition and water on seismic discontinuity in earth was discussed.

通过第一性原理结合准简谐德拜模型研究了α和β镁橄榄石的高温高压结构及相变特征；计算了α和β镁橄榄石的弹性模量、波速、电子带结构、带隙等随压力的变化规律，并探讨了相变对这些性质的影响；研究了水对α镁橄榄石弹性模量、波速和带隙的影响；探讨了水对地幔中不连续层的作用以及矿物相变对过渡带波速不连续的作用。

The results show that the gas flow is represented as laminar flow in flat nozzle contour and turbulent flow in scraggling nozzle contour; The development of turbulent flow is good for the control effect of super-sound velocity gas flow and the dielectric strength recovery properties.

光滑喷口壁面吹弧气体的流动表现为层流；凸凹不平的喷口壁面吹弧气体的流动表现为湍流；对存在有湍流的不同喷口，湍流发展得越充分，越有利于控制超音速流的发展，从而有利于提高介质强度恢复速度。

The precision of the traditional ultrasonic localization method is limited due to unsufficiently precise estimation of the sound velocity and the time of flight, therefore, a new method, the special fusion method for redundancy ultrasonic information was proposed to solve the precision problem.

针对常规的超声波定位方法存在对决定定位精度的声速与渡越时间估算不准，导致定位精度有限的问题，提出了一种新的超声波绝对定位方法，即冗余超声波信息特殊融合法。

Moreover, the accuracy analysis for different measurements and parameters(such as time measure error, azimuth measure error, buoys error, baseline length and sound velocity fluctuation) are given respectively. To make the best use of the observation datas, the weighted least square localization algorithm is used to improve the accuracy in bistatic sonar. The simulation results show that the positioning accuracy of this algorithm is higher than the other four algorithms, with which the positioning accuracy in stations areas and side areas can be improved effectively.

同时，通过对系统各个因素，如系统的各观测量的测量误差、站址误差、基线长度、声速波动等参数对算法性能的影响，得出了各方法定位误差的分布规律；为了充分利用双基地声纳系统的观测数据，提高系统的定位精度，采用加权最小二乘方法对系统的数据进行优化处理，仿真结果表明该方法定位精度明显高于基本方法的定位精度，能有效的改善发射站和接受站侧边区的定位精度，且定位性能受站址测量误差的影响较小。

This paper will systematically expatiate the interrelation and interaction between the factors of sound velocity, instrument correction and index etc.

结合黄骅港水深测量数据，针对声速剖面测量与声速改正以及声速、器差、指标差等要素间的内在联系及相互影响予以系统阐述。

One of the latest requirements in littoral waters is Rapid Environment Assessment, providing deployed forces and/or vessels with appropriate environmental and oceanographic information of the waters and seabed, such as currents, bathymetry, sound velocity, seabed materials, water visibility and so on.

在滨海水域的一个最新需求是迅速的环境评估，提供部署力量和/或舰艇，同水域和海底的适当环境和海洋学信息，如此被当做当前的、测海学、声音速率、海床物质、海水能见度等等。

For the x=0.03 sample, both the minimum of sound velocity and attenuation peaks shift to a lower temperature.

在低温下，出现了另一个超声衰减峰，它的出现归结为反铁磁相与顺磁相之间的相分离现象。

For the x=0.03 sample, both the minimum of sound velocity and attenuation peaks shift to a lower temperature. The results indicate that the charge ordering and CE-type AFM state in Nd0.5Ca0.5MnO3 are both partially suppressed by replacing Mn with Al.

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According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。