共查询到19条相似文献,搜索用时 593 毫秒
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利用推广的双曲函数展开法,得到了具强迫项的变系数Burgers方程的几组带有任意函数和任意常数的精确解.根据得到的解,分析了各种可能的孤波结构,发现了运动学特征不同于通常扭结孤立波的特殊扭结孤立波. 相似文献
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考虑浅水波方程,对二维非结构网格给出了一种非振荡有限体积方法.该方法的主要思想是在每一个三角形单元上采用最小二乘的思想构造一个重构函数,而时间离散采用二步TVD Runge- Kutta方法.最后用该格式对二维溃坝问题进行了数值试验,得到了满意的结果. 相似文献
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不同于传统流体力学,在Lagrange坐标下推导浅水波方程.若将水平位移作为基本变量,则推导出的浅水波数学模型可描述为固体力学的非线性大位移问题.运用不可压缩条件,通过变分原理推导出位移法浅水波方程,给出椭圆函数形式的行波解,并分析孤波解产生的条件.该基础研究建立了在分析结构力学中分析浅水波问题的理论基础,有利于进一步开展水动力学的研究. 相似文献
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把谱元法应用于刚架结构的动力学响应计算和分析中.建立了杆和梁的谱单元动力学刚度阵,针对刚架结构组装了整体动力学刚度阵,建立了整体结构的运动方程,计算了结构的固有频率和时域响应,并与采用有限元方法得到的结果进行了对比.从结果中可以看出谱元法在数值模拟中的独特优势. 相似文献
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本文研究了一种二维三角陀螺声子晶体,采用拉格朗日方程对结构进行建模,推导出动力学方程.通过调节陀螺转速,可以控制结构的色散关系,并获得较大的带隙,从而可以将其用来进行振动控制和噪声抑制.从色散曲面等频截线发现波在结构中的传播方向会随频率变化,在低频时各向同等传播,高频时则出现六个集中的传播方向.通过数值计算验证了理论获得的带隙的准确性. 相似文献
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首先,提出了一种二维平面陀螺声子晶体,得到了不同参数对带隙的影响.该结构由陀螺、外框架、弹簧组成.其次,在结构中只考虑由于陀螺转动引起的角运动,不考虑平移.运用角动量定理,针对该结构建立动力学方程.然后,通过动力学方程,分析其带隙特性得到色散曲面.随后,通过改变结构中的参数,观察带隙的变化,得到了不同参数对带隙的影响.最后,用数值方法验证其带隙的存在,证明了这种二维平面陀螺声子晶体能对扭转振动具有抑制作用. 相似文献
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乐甫波器件适于液体检测,但在工程上经常因为激发效率较低而影响应用。与“压电基底-非压电薄膜”的单压电结构乐甫波器件相比,双压电结构的特点是薄膜也选用压电材料,以期增大器件整体的压电效应。在建立理论模型的基础上,通过空气中和液体检测时双压电结构乐甫波与声表面波、单压电结构乐甫波的机电耦合系数仿真并对比,表明对于某些压电基底和薄膜,双压电结构具有更高的乐甫波激发效率。并且,以液体介电常数检测为例,仿真结果还表明了双压电结构乐甫波比单压电结构具有更高的灵敏度。 相似文献
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Yan WangAuthor VitaeShu-yi ZhangAuthor Vitae Feng-mei ZhouAuthor VitaeLi FanAuthor Vitae Yue-tao YangAuthor VitaeCheng WangAuthor Vitae 《Sensors and actuators. B, Chemical》2011,158(1):97-103
Love wave hydrogen sensors based on ZnO nanorod layers deposited on 36°YX-LiTaO3 substrates have been studied. The ZnO nanorod layers are prepared by two steps: first, the seed layers, as well the guiding layers of the Love wave devices, are deposited by RF magnetron sputtering; second, the nanostructural layers, as well the sensing layers of the sensors, are grown by hydrothermal synthesis. Two kinds of ZnO layers have been analyzed by XRD, SEM and XPS. The XRD shows that both ZnO layers have (0 0 2) oriented wurtzite structures. The SEM results reveal that the morphologies of the deposited ZnO seed layers are continuous and compact, while the hydrothermal treated layers are with nanorods almost perpendicular to the substrate surfaces. Finally, the hydrogen sensing responses of the Love wave sensors activated by Pt catalysts are measured for various concentrations of hydrogen in synthetic air at room temperature. The results show that the sensors have high sensitivity and repeatability as the nanorod layers are optimized, such as the frequency shift 8 kHz toward 0.04% of H2 in synthetic air is obtained while the height of the nanorod layer is about 2.1 μm and the central frequency of the sensor is about 125.5 MHz. The XPS analyses of the sensitive layers show that there are oxygen vacancies in the layers, so the oxygen vacancy model is used to explain the hydrogen sensing mechanism of the Love wave sensors. 相似文献
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Ying-San Lai 《Computers & Structures》1974,4(5):961-966
Numerical procedures of the method of characteristics is presented to treat the problems of multilayered structures under impulsive load. A set of eight algebraic equations which are readily to be programmed into computer are derived. Stress analysis of a typical dynamic layered structure is given to illustrate the effectiveness of the method. Results of the example problem reveal the fact that pulse shape is very sensitive to transient stress wave propagation. 相似文献
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A sandy sea bottom is seen as a structure with low stiffness which adapts to the motion of water in a shallow domain described by the Saint Venant equations. The coupling is based on the minimization of water wave energy with minimal sand transport. The approach is shown being similar to the use of an original Exner equation for the bottom with non local flux expressions. Also, examples of the applications of the framework to inverse problems in coastal engineering are shown. 相似文献
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Laurent Marc Marc Jean-Olivier Laurence Rmi Oleg Cline Corinne Dominique 《Sensors and actuators. B, Chemical》2009,140(2):616-622
A new novel and easy functionalization route of a Love wave acoustic sensor based on the α-oxo-semicarbazone bond is described. The interest is firstly to observe in real-time the immobilization of the peptide on the semicarbazide surface of the transducer and secondly to monitor the specific binding of antibodies. Site-specific immobilization of antigenic-peptides as well as binding of murine monoclonal antibodies has been shown by gravimetric measurements. A tetramethylrhodamine-labeled goat antibody directed against murine antibodies was used to further characterize the biomolecular interactions by fluorescence microscopy and surface analysis (by AFM). Our data show that the gravimetric monitoring developed from the prepared Love wave immunosensor is a promising alternative route to characterize chemical and biomolecular events. 相似文献
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《国际计算机数学杂志》2012,89(12):959-971
In this paper, the bifurcation method of the dynamical and numerical approach to differential equations to study higher order wave equations of Korteweg–de Vries (KdV) type is used. With this methodology we obtain the compacton-like and kink-like wave solutions of the high order KdV type equation. Their implicit expressions are given and their planar graphs are simulated. The results show that the numerical integrations are identical with the theoretical derivations. 相似文献
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Pengzhi Lin 《Computers & Fluids》2006,35(2):147-167
A 3D multiple-layer σ-coordinate model has been developed to simulate surface wave interaction with various types of structures including submerged structures, immersed structures, and floating structures. This model is the extension of the earlier model [Lin P, Li CW. A σ-coordinate three-dimensional numerical model for surface wave propagation. Int J Numer Methods Fluid 2002;38(11):1045-68] that solves Navier-Stokes equations in the transformed σ-coordinate, which is especially efficient for simulation of wave propagation over varying topography. By introducing the layered σ-coordinates, the present model overcomes the difficulty encountered by the earlier model in calculating waves past a depth discontinuity, e.g., a submerged rectangular breakwater. Furthermore, with the employment of 3-layer σ-coordinate the present model is able to simulate flow interaction with an immersed body or a floating body. The new model is validated against an established Volume-Of-Fluid (VOF) model [Lin P, Liu PL-F. A numerical study of breaking waves in the surf zone. J Fluid Mech 1998;359:239-64] for the 2D solitary wave interaction with a submerged, immersed, or floating rectangular obstacle. For the solitary wave interaction with a submerged breakwater, the numerical results are also compared to the experimental data by Zhuang and Lee [A viscous rotational model for wave overtopping over marine structure. In Proc 25th Int Conf Coast Eng, ASCE, 1996. p. 2178-91] and very good agreements have been obtained for velocities in the vortex behind the structure. Finally, the present model is used to simulate 3D wave interaction with a Very Large Floating Structure (VLFS) above a submerged shoal. It is proved that the model is an accurate and efficient numerical tool to investigate different wave-structure interactions problems. 相似文献
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Effect of magnesium doping on the structural and piezoelectric properties of sputtered ZnO thin film
Structural and piezoelectric characteristics of magnesium-doped ZnO films were investigated. Magnesium-doped ZnO films with a c-axis preferred orientation were deposited on ST-cut quartz by radio frequency magnetron sputtering. The crystalline structure and surface morphology of films were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy. The electromechanical coupling coefficient and temperature coefficient of frequency of the filters were then determined using a Love wave filter. A uniform crystalline structure and smooth surface of the ZnO films were obtained when magnesium dopant level was 1.5 mol%. The grain size of the ZnO film increased when magnesium doped. It has been found that the temperature coefficient of frequency declines to +0.44 ppm/°C at 1.5 mol% magnesium-doped ZnO film. 相似文献