Three-dimensional coupled-mode model and characteristics of low-frequency sound propagation in ocean waveguide with seamount topography

Large-scale topography, such as a seamount, substantially impacts low-frequency sound propagation in an ocean waveguide, limiting the application of low-frequency acoustic detecting techniques. A three-dimensional (3D) coupled-mode model is developed to calculate the acoustic field in an ocean waveguide with seamount topography and analyze the 3D effect. In this model, a correction is introduced in the bottom boundary, theoretically making the acoustic field satisfy the energy conservation. Furthermore, a large azimuth angle calculation range is obtained by using the operator theory and higher-order Padé approximation. Additionally, the model has advantages related to the coupling mode and parabolic equation theory. The couplings corresponding to the effects of range-dependent environment are fully considered, and the numerical implementation is kept feasible. After verifying the accuracy and reliability of the model, low-frequency sound propagation characteristics in the seamount environment are analyzed. The results indicate lateral variability in bathymetry can lead to out-of-plane effects such as the horizontal refraction phenomenon, while the coupling effect tends to restore the abnormal sound field and produces acoustic field diffraction behind the seamount. This model effectively considers the effects of the horizontal refraction and coupling, which are proportional to the scale of the seamount.     

A New Unsteady Three Dimensional Model for Macromolecular Transport and Water Filtration Across the Arterial Wall

ＩｎｔｒｏｄｕｃｔｉｏｎＡｔｈｅｒｏｇｅｎｅｓｉｓ,ｏｎｅｏｆｔｈｅｍａｊｏｒｃａｕｓｅｓｆｏｒｔｈｅｄｅａｔｈｏｆｐｅｏｐｌｅｉｎｗｅｓｔｅｒｎｃｏｕｎｔｒｉｅｓ,ｈａｓｔｗｏｐｒｏｍｉｎｅｎｔｐｒｏｐｅｒｔｉｅｓ.Ｆｉｒｓｔ,ｉｔｕｓｕａｌｌｙｔａｋｅｓｐｌａｃｅａｔｔｈｅｂｒａｎｃｈｅｓｏｒｃｕｒｖａｔｕｒｅｓｏｆｔｈｅｂｉｇａｒｔｅｒｉｅｓ,ｗｈｅｒｅｔｈｅｒｅｉｓａｎａｂｒｕｐｔｃｈａｎｇｅｏｆｂｌｏｏｄｆｌｏｗ .Ｓｅｃｏｎｄｌｙ ,ｔｈｅｒｅｉｓａｎａｃｃｕｍｕｌａｔｉｏｎｏｆｌｏｃａｌｆ…     

等离子体反应器中传热与流动的三维数值模拟

本文采用我们新发展的三维计算机程序,对有载气和颗粒从单个喷孔侧向喷射的等离子体反应器中的传热与流动以及颗粒的运动轨迹与加热历程进行了三维数值模拟,并与相应的二维数值模拟结果进行了比较。模拟结果表明侧向喷入的载气所引起的三维流动效应相当明显,不同的颗粒在反应器内的运动轨迹与加热历程也有明显差别。     

咪唑配合物[Co(C3H4N2)6](PhCHCHCOO)2的合成及晶体结构

The complex [Co(Im)6](Cin)2 (Im=imidazole,Cin=cinnamate) was prepared by reaction of Co(PhCHCHCOO)2 with imidazole in ethanol. It has been determined by single crystal X-ray analyses. The crystals are triclinic, space group P, with a=9.7601(3),b=10.5935(3),c=11.3269(2)(A),α =69.948(1),β =71.027(1),γ =62.803(1)°, and Z=1. The crystal structure of the title complex consists of monomeric [Co(Im)6]2+ cations and cinnamate anions in which the cobalt(Ⅱ) ion assumes a centrosymmetric octahedral geometry with the CoN6 chromophore. In the solid state, the complex forms a three dimensional network through N-H… O hydrogen bonds, the intermolecular hydrogen bonds connect the [Co(Im)6]2+ cations and cinnamate anions.The cinnamate anions are nearly planar.     

Computer-Generated Holograms Based on the Three-Dimensional Fourier Spectrum

A method to synthesize a computer-generated hologram (CGH) of real-existing objects from projection images is proposed. Different from other similar methods, our method enables the synthesis of a CGH with only one-dimensional (1-D) mechanical scanning of the objects. Our method is connected with the three-dimensional (3-D) Fourier spectrum of the objects by the 3-D central slice theorem (CST). Two efficient recording techniques for projection images and numerical experiments to verify our principle is discussed. A comparison between the two techniques is also presented from the viewpoint of diffraction efficiency. © 2005 The Optical Society of Japan     

Hydrothermal Synthesis, Crystal Structure and Fluorescence Property of a Novel Coordination Polymer [Eu_2(C_6H_8O_4)_3(H_2O)_2]_n·n(4,4′-bpy)

1UINTRODCTIONAtpresentthefluorescentmaterialsusedaremostlyinorganicororganicmicromolecularlumine-scentmaterialsthatareeasilyattenuatedinsunlight.Thereforepeopleintendtostudythepolymerflu-orescentmaterialscontainingrare-earthionsduetotheirgoodfluorescenthomochromepropertyandhighluminescentintensity.Inrecentyearswidestudieshavebeenperformed[1～10]tosearchforlu-minescentmaterialswithfineluminescentproper-tiesatlowprice.Asfortherare-earthcoordinationpolymer,agreatnumberofinvestigationsaremain…     

连续调制光热辐射测量技术的三维理论模型

建立了连续调制光热辐射测量(PTR)的三维理论模型.理论值与实验结果符合良好,成功地解释了-维模型不能说明的结果.     

板条固体激光器的三维瞬态热分布

本文建立了有限几何尺寸板条激光介质的三维温度分布模型.在普遍情况下,推导出温度分布的解析式.由此便于分析板条温度分布和泵浦参数、激光介质等的依赖关系.借助计算机进行的数值计算,证实了理论结果.     

一种大视场相位测量轮廓术系统标定方法

在进行大视场相位测量轮廓术系统参量标定时需要大的标定平面和精密移动台,由于携带不方便,不易进行现场标定。提出了一种用于相位测量轮廓术系统参量的高精度、现场标定方法,采用一块较小的平面标定靶在有效测量体积内不同位置多次摆放,以获取密集的数据点。先标定出摄像机的内参量和外参量,再指定一个全局参考平面和若干辅助参考平面,然后在图像平面上分区计算出每个位置标定靶上每点相对辅助参考平面的高度差和相位差,最后应用极大似然估计法估计出相位高度映射参量。实验中平面高度测量的标准偏差达到0.0433 mm。这种方法只需要较小的平面标定靶,标定过程方便、精度高,完全适合大视场三维测量相位测量轮廓术系统现场标定要求。     

Wave Regimes of Viscous Film Flow down a Vertical Cylinder

The flow of a viscous liquid film down a vertical cylinder in the gravity field is considered. In the case of small Reynolds numbers for long-wave perturbations on a cylinder of radius much greater than the film thickness, the problem can be reduced to a single nonlinear equation for the evolution of the film thickness perturbation. For axially symmetric solutions, this equation coincides with the well-known Sivashinsky-Kuramoto equation. The results of a numerical analysis of this equation for three-dimensional stationary traveling solutions of the problem are reported. The effect of the problem parameters on the solution behavior is demonstrated. Soliton type solutions are presented.