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导流壳几何参数选取及其对泵性能的影响 被引量:26
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作者 赵秋霞 《太原理工大学学报》 CAS 2002年第4期414-416,共3页
针对井用泵的特点 ,根据多个水力模型的设计、试制、试验 ,总结分析了导流壳几何参数对泵性能的影响 ,提出了几何参数选取范围 。
关键词 参数选取 导流壳 几何参数 水力模型 空间导叶
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VB与FORTRAN混合编程的两种方法及其比较 被引量:10
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作者 何萌 柴军瑞 《水电能源科学》 2005年第1期60-62,共3页
介绍和比较 VB直接调用 Fortran编译的可执行文件和 VB调用 Fortran动态链接库两种实现 VB和Fortran混合编程的方法 ,给出了实现 VB和 Fortran混合编程的具体实例 。
关键词 水利数值计算 VB FORTRAN 混合编程 shell函数 动态链接库
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基于VC++和FORTRAN混合编程的优化系统设计 被引量:8
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作者 边炳传 龙连春 +1 位作者 隋允康 张学胜 《计算机工程与设计》 CSCD 北大核心 2006年第11期2046-2048,共3页
用VC++和FORTRAN语言混合编程的方法进行优化系统的设计,不但可以方便地进行优化算法的设计和友好的人机界面设计,还能够实现并行地进行软件系统的开发,可以有效地缩短程序设计时间。对外壳函数调用FORTRAN生成的可执行文件时系统出现... 用VC++和FORTRAN语言混合编程的方法进行优化系统的设计,不但可以方便地进行优化算法的设计和友好的人机界面设计,还能够实现并行地进行软件系统的开发,可以有效地缩短程序设计时间。对外壳函数调用FORTRAN生成的可执行文件时系统出现的异步执行问题和“黑屏”问题提出了解决办法,最后给出了优化系统的设计实例,验证了该方法的可行性和有效性。 展开更多
关键词 混合编程 优化算法 优化系统 外壳函数 异步执行
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贝壳利用研究进展 被引量:9
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作者 王帅 刘志东 +3 位作者 曲映红 蒋玫 李磊 唐保军 《渔业信息与战略》 2018年第1期30-35,共6页
本文介绍了我国贝壳的年产量,利用情况和存在的问题;总结了贝壳的基本结构和化学组成,分析了不同种类、来源贝壳的宏观结构和微观结构差异;综述了贝壳及其产物的主要功能特性(光学特性、力学特性、吸附特性、生物相容性和生物活性等)和... 本文介绍了我国贝壳的年产量,利用情况和存在的问题;总结了贝壳的基本结构和化学组成,分析了不同种类、来源贝壳的宏观结构和微观结构差异;综述了贝壳及其产物的主要功能特性(光学特性、力学特性、吸附特性、生物相容性和生物活性等)和利用研究进展,预测了贝壳利用的可能领域,期望本文能为推动我国贝壳资源的深度开发利用提供参考。 展开更多
关键词 贝壳 结构特征 功能特性 利用 研究进展
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波纹壳的格林函数方法 被引量:9
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作者 袁鸿 张湘伟 《应用数学和力学》 EI CSCD 北大核心 2005年第7期763-769,共7页
 应用轴对称旋转扁壳的基本方程,研究了在任意载荷作用下具有型面锥度的浅波纹壳的非线性弯曲问题· 采用格林函数方法,将扁壳的非线性微分方程组化为非线性积分方程组· 再使用展开法求出格林函数,即将格林函数展成特征函...  应用轴对称旋转扁壳的基本方程,研究了在任意载荷作用下具有型面锥度的浅波纹壳的非线性弯曲问题· 采用格林函数方法,将扁壳的非线性微分方程组化为非线性积分方程组· 再使用展开法求出格林函数,即将格林函数展成特征函数的级数形式,积分方程就成为具有退化核的形式,从而容易得到非线性代数方程组· 应用牛顿法求解非线性代数方程组时,为了保证迭代的收敛性,选取位移作为控制参数,逐步增加位移,求得相应的载荷· 在算例中,研究了具有球面度的浅波纹壳的弹性特征· 结果表明,由于型面锥度的引入,特征曲线发生显著变化,随着荷载的增加。 展开更多
关键词 波纹壳 格林函数 积分方程 非线性弯曲 弹性特征
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均布载荷作用下波纹扁壳的非线性振动 被引量:7
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作者 袁鸿 刘人怀 《应用数学和力学》 EI CSCD 北大核心 2007年第5期514-520,共7页
应用轴对称旋转扁壳的非线性大挠度动力学方程,研究了波纹扁壳在均布载荷作用下的非线性受迫振动问题.采用格林函数方法,将扁壳的非线性偏微分方程组化为非线性积分微分方程组.再使用展开法求出格林函数,即将格林函数展开为特征函数的... 应用轴对称旋转扁壳的非线性大挠度动力学方程,研究了波纹扁壳在均布载荷作用下的非线性受迫振动问题.采用格林函数方法,将扁壳的非线性偏微分方程组化为非线性积分微分方程组.再使用展开法求出格林函数,即将格林函数展开为特征函数的级数形式,积分微分方程就成为具有退化核的形式,从而容易得到关于时间的非线性常微分方程组.针对单模态振形,得到了谐和激励作用下的幅频响应.作为算例,研究了正弦波纹扁球壳的非线性受迫振动现象.该文的解答可供波纹壳的设计参考. 展开更多
关键词 波纹壳 球壳 格林函数 积分方程 非线性振动
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Electrostatic Attraction and Repulsion Explained and Modelled Mathematically Using Classical Physics—A Detailed Mechanism Based on Particle Wave Functions
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作者 Declan Traill 《Journal of Applied Mathematics and Physics》 2024年第4期1050-1062,共13页
The phenomenon of electrical attraction and repulsion between charged particles is well known, and described mathematically by Coulomb’s Law, yet until now there has been no explanation for why this occurs. There has... The phenomenon of electrical attraction and repulsion between charged particles is well known, and described mathematically by Coulomb’s Law, yet until now there has been no explanation for why this occurs. There has been no mechanistic explanation that reveals what causes the charged particles to accelerate, either towards or away from each other. This paper gives a detailed explanation of the phenomena of electrical attraction and repulsion based on my previous work that determined the exact wave-function solutions for both the Electron and the Positron. It is revealed that the effects are caused by wave interactions between the wave functions that result in Electromagnetic reflections of parts of the particle’s wave functions, causing a change in their momenta. 展开更多
关键词 ELECTROSTATIC Electron POSITRON COULOMB Force ATTRACTION REPULSION Wave function Electric Magnetic Radiation Pressure shell THEOREM 3D Computer Model Quantum
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Mathematical Wave Functions and 3D Finite Element Modelling of the Electron and Positron
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作者 Declan Traill 《Journal of Applied Mathematics and Physics》 2024年第4期1134-1162,共29页
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an... The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles. 展开更多
关键词 ELECTRON POSITRON Wave function Solution Electromagnetic Spin Mass Charge Proof Fundamental Particle Properties Quantum Mechanics Classical Physics Computer 3D Model Schrödinger Equation RMS KLEIN GORDON Electric Magnetic Lorentz Invariant Hertzian Vector Point Potential Field Density Phase Flow Attraction REPULSION shell Theorem Ehrenfest VIRIAL Normalization Harmonic Oscillator
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锥壳的位移解及应用 被引量:4
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作者 黄义 《应用数学和力学》 EI CSCD 北大核心 1991年第2期149-164,共16页
本文提出求锥壳方程通解的另一种方法——位移法.文中根据文献[1]给出的壳体基本关系,导出锥壳一般弯曲问题的位移方程组,然后通过引入一个位移函数U(s,θ)(在极限情况下,就变为对于圆柱壳所引入的位移函数),从而将锥壳基本方程组化成... 本文提出求锥壳方程通解的另一种方法——位移法.文中根据文献[1]给出的壳体基本关系,导出锥壳一般弯曲问题的位移方程组,然后通过引入一个位移函数U(s,θ)(在极限情况下,就变为对于圆柱壳所引入的位移函数),从而将锥壳基本方程组化成关于位移函数U(s,θ)的8阶可解偏微分方程(控制微分方程).对于一般弯曲问题,该方程的一般解以广义超几何函数给出;对于轴对称弯曲问题,用Bessel函数给出其一般解.作为锥壳位移解法的应用,讨论了Winkler地基模式上的锥壳的轴对称弯曲问题,给出数值结果. 展开更多
关键词 锥壳 位移函数 弹性地基
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FREE VIBRATION OF PIEZOELECTRIC CYLINDRICAL SHELLS 被引量:5
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作者 Ding, HJ Guo, YM +1 位作者 Yang, QD Chen, WQ 《Acta Mechanica Solida Sinica》 SCIE EI 1997年第1期48-55,共8页
Three displacement functions are introduced to represent each mechanical displacement according to the 3-D theory in this paper. By expanding the displacement functions and the electric potential in orthogonal series,... Three displacement functions are introduced to represent each mechanical displacement according to the 3-D theory in this paper. By expanding the displacement functions and the electric potential in orthogonal series, the free vibration equation of piezoelectric cylindrical shells satisfying SS3 boundary conditions can be obtained. The equation was solved by utilizing Bessel functions with complex arguments. Results are presented graphically as well as in table, and compared with those of other references. Some frequencies that were missing in Ref. [9] are discovered. 展开更多
关键词 piezoelectric material displacement function free vibration of cylindrical shell
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GREEN QUASIFUNCTION METHOD FOR FREE VIBRATION OF SIMPLY-SUPPORTED TRAPEZOIDAL SHALLOW SPHERICAL SHELL ON WINKLER FOUNDATION 被引量:5
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作者 Shanqing Li Hong Yuan (MOE Key Laboratory of Disaster Forecast and Control in Engineering, Institute of Applied Mechanics, Jinan University, Guangzhou 510632, China) 《Acta Mechanica Solida Sinica》 SCIE EI 2010年第4期370-376,共7页
The idea of Green quasifunction method is clarified in detail by considering a free vibration problem of simply-supported trapezoidal shallow spherical shell on Winkler foundation.A Green quasifunction is established ... The idea of Green quasifunction method is clarified in detail by considering a free vibration problem of simply-supported trapezoidal shallow spherical shell on Winkler foundation.A Green quasifunction is established by using the fundamental solution and boundary equation of the problem.This function satisfies the homogeneous boundary condition of the problem.The mode shape differential equation of the free vibration problem of simply-supported trapezoidal shallow spherical shell on Winkler foundation is reduced to two simultaneous Fredholm integral equations of the second kind by Green formula.There are multiple choices for the normalized boundary equation.Based on a chosen normalized boundary equation, the irregularity of the kernel of integral equations is avoided.Finally, natural frequency is obtained by the condition that there exists a nontrivial solution in the numerically discrete algebraic equations derived from the integral equations.Numerical results show high accuracy of the Green quasifunction method. 展开更多
关键词 Green function integral equation shallow spherical shell free vibration Winkler foundation
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圆柱壳结构振动功率流和主动力幅值的控制研究 被引量:6
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作者 金全洲 李天匀 +1 位作者 赵耀 严谨 《船舶力学》 EI 北大核心 2009年第2期305-312,共8页
以输入结构的总功率流和所需主动力幅值为控制目标函数,对输入圆柱壳结构振动功率流的主动控制进行了研究,并分析了几个重要参数对壳体结构振动功率流控制效果的影响。利用导纳函数求解结构响应,构造目标函数为二次型函数形式,利用哈密... 以输入结构的总功率流和所需主动力幅值为控制目标函数,对输入圆柱壳结构振动功率流的主动控制进行了研究,并分析了几个重要参数对壳体结构振动功率流控制效果的影响。利用导纳函数求解结构响应,构造目标函数为二次型函数形式,利用哈密尔顿二次型最小值理论给出最优控制力前馈控制表达式。 展开更多
关键词 圆柱壳 振动功率流 主动控制 导纳函数
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基于梁函数-Ritz法的圆柱壳模态特性分析
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作者 徐港辉 祝长生 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2023年第9期1794-1803,共10页
单项梁函数作为圆柱壳轴向振型容许函数时计算精度不足,基于不同薄壳理论所得研究结果难以直接对比,为此将梁函数与Ritz法相结合,建立包含不同薄壳理论的统一方法,用于分析圆柱壳模态特性.当梁函数项数取1时,梁函数-Ritz法退化为单项梁... 单项梁函数作为圆柱壳轴向振型容许函数时计算精度不足,基于不同薄壳理论所得研究结果难以直接对比,为此将梁函数与Ritz法相结合,建立包含不同薄壳理论的统一方法,用于分析圆柱壳模态特性.当梁函数项数取1时,梁函数-Ritz法退化为单项梁函数法,即单项梁函数法是梁函数-Ritz法的特例.通过与有限元仿真及现有文献数据的对比,澄清现有文献在梁函数是否适用于模拟圆柱壳固支或自由边界条件上存在的分歧.在不同边界条件下,总结长径比与厚径比对圆柱壳模态频率及理论计算精度的影响规律,得出不同薄壳理论的适用范围.考虑的薄壳理论包括Donnell、Reissner、Sanders及Love理论.结果表明,梁函数-Ritz法可以有效提升单项梁函数法的计算精度;Donnell理论的计算精度明显低于其他3种理论. 展开更多
关键词 圆柱壳 模态 梁函数 容许函数 RITZ法 薄壳理论
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EXACT STATIC ANALYSIS OF A ROTATING PIEZOELECTRIC SPHERICAL SHELL 被引量:3
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作者 陈伟球 丁皓江 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1998年第3期257-265,共9页
An exact analysis of a rotating piezoelectric spherical shell with arbitrary thickness is given. Three displacement functions are introduced to simplify the basic equations of a spherically isotropic, piezoelectric m... An exact analysis of a rotating piezoelectric spherical shell with arbitrary thickness is given. Three displacement functions are introduced to simplify the basic equations of a spherically isotropic, piezoelectric medium. By expanding the displacement functions as well as the electric potential in terms of spherical harmonics, the basic equations of equilibrium are converted to an uncoupled Euler type, second order ordinary differential equation and a coupled system of three second order ordinary differential equations. A general solution to the homogeneous equations of equilibrium is then derived. The static analysis of a rotating spherical shell is performed and the numerical example is presented. (Edited author abstract) 13 Refs. 展开更多
关键词 piezoelectric medium spherical isotropy displacement function rotating spherical shell
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A Lightweight Electronic Water Pump Shell Defect Detection Method Based on Improved YOLOv5s
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作者 Qunbiao Wu Zhen Wang +2 位作者 Haifeng Fang Junji Chen Xinfeng Wan 《Computer Systems Science & Engineering》 SCIE EI 2023年第7期961-979,共19页
For surface defects in electronic water pump shells,the manual detection efficiency is low,prone to misdetection and leak detection,and encounters problems,such as uncertainty.To improve the speed and accuracy of surf... For surface defects in electronic water pump shells,the manual detection efficiency is low,prone to misdetection and leak detection,and encounters problems,such as uncertainty.To improve the speed and accuracy of surface defect detection,a lightweight detection method based on an improved YOLOv5s method is proposed to replace the traditional manual detection methods.In this method,the MobileNetV3 module replaces the backbone network of YOLOv5s,depth-separable convolution is introduced,the parameters and calculations are reduced,and CIoU_Loss is used as the loss function of the boundary box regression to improve its detection accuracy.A dataset of electronic pump shell defects is established,and the performance of the improved method is evaluated by comparing it with that of the original method.The results show that the parameters and FLOPs are reduced by 49.83%and 61.59%,respectively,compared with the original YOLOv5s model,and the detection accuracy is improved by 1.74%,which is an indication of the superiority of the improved method.To further verify the universality of the improved method,it is compared with the results using the original method on the PASCALVOC2007 dataset,which verifies that it yields better performance.In summary,the improved lightweight method can be used for the real-time detection of electronic water pump shell defects. 展开更多
关键词 Electronic water pump shell surface defect detection lightweight network loss function
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THE DISPLACEMENT SOLUTION OF CONICAL SHELL AND ITS APPLICATION
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作者 黄义 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1991年第2期163-180,共18页
In this paper, the displacement solution method of the conical shell is presented. From the differential equations in displacement form of conical shell and by introducing a displacement function, U,the differential e... In this paper, the displacement solution method of the conical shell is presented. From the differential equations in displacement form of conical shell and by introducing a displacement function, U,the differential equations are changed into an eight-order soluble partial differential equation about the displacement Junction U in which the coefficients are variable. A t the same time, the expressions of the displacement and internal force components of the shell are also given by the displacement function. As special cases of this paper, the displacement function introduced by V. Z. Vlasov in circular cylindrical shell, the basic equation of the cylindrical shell and that of the circular plate are directly derived.Under the arbitrary loads and boundary conditions, the general bending problem of the conical shell is reduced to finding the displacement functionU,and the general solution of the governing equation is obtained in generalized hypergeometric function, For the axisymmetric bending deformation of the conical shell, the general solution is expressed in the Bessel functionOn the basis of the governing equation obtained in this paper, the differential equation of conical shell on the elastic foundation (A Winkler Medium) is deduced, its general solutions are given in a power series, and the numerical calculations are carried out. 展开更多
关键词 conical shell displacement function generalized hypergeometric function elastic foundation
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曲面薄壳有限元离散误差分析和修正方法研究 被引量:2
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作者 刘建涛 杜平安 +2 位作者 黄明镜 刘孝保 石峥 《系统仿真学报》 CAS CSCD 北大核心 2010年第10期2281-2286,共6页
基于曲面薄壳几何/物理方程和有限元离散原理推导,揭示了壳单元离散方法特点、刚度矩阵误差产生机理和范数表示方法。以航空涡轮发动机测压探针为例,深入研究了利用协调平板壳单元、非协调平板壳单元、一次和二次实体退化壳单元等不同... 基于曲面薄壳几何/物理方程和有限元离散原理推导,揭示了壳单元离散方法特点、刚度矩阵误差产生机理和范数表示方法。以航空涡轮发动机测压探针为例,深入研究了利用协调平板壳单元、非协调平板壳单元、一次和二次实体退化壳单元等不同类型单元离散曲面薄壳时,应力计算误差影响因素及变化规律,综述了单元的适用条件。基于Boltzmann模型提出了应力计算结果修正通式,通过FORTRAN语言编程修正应力仿真结果和ANSYS二次开发语言APDL命令实现应力修正结果的读取和后处理,应力修正结果与理论解相对误差小于5%,满足曲面薄壳设计和稳定性分析应用要求。 展开更多
关键词 曲面薄壳 壳单元 形函数 误差分析 修正函数
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基于Fe_2O_3催化剂的花生壳热解特性及动力学研究 被引量:3
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作者 张彬 董晶晶 王文举 《精细石油化工》 CAS CSCD 北大核心 2017年第1期77-82,共6页
采用非等温法对Fe_2O_3催化剂催化花生壳的热解进行了研究,用双外推法对花生壳热解过程进行了动力学分析,获得了相应的动力学参数。实验结果表明,升温速率的增加可以提高花生壳的热解速率;Fe_2O_3催化剂的加入促进了花生壳的热解,使得... 采用非等温法对Fe_2O_3催化剂催化花生壳的热解进行了研究,用双外推法对花生壳热解过程进行了动力学分析,获得了相应的动力学参数。实验结果表明,升温速率的增加可以提高花生壳的热解速率;Fe_2O_3催化剂的加入促进了花生壳的热解,使得热解后的最终失重量增加了51.19%。动力学研究结果表明,Fe_2O_3催化剂没有改变热解过程的反应机理,其动力学机理函数始终保持为Mample单行法则,机理函数的积分式为-ln(1-α)。两种条件下的热解活化能分别为153.30kJ/mol和134.22kJ/mol,Fe_2O_3催化剂的加入使得花生壳热解过程的活化能降低了12.45%。 展开更多
关键词 花生壳 催化热解 Fe2O3双外推法 机理函数
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浅海中圆柱壳的声辐射特性分析 被引量:3
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作者 缪宇跃 李天匀 +2 位作者 朱翔 王鹏 张冠军 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2017年第5期719-726,共8页
根据声学边界元理论,本文在考虑海面和吸声海底的声反射作用基础上,对格林函数进行修正,建立波导域声辐射模型,并分析了浅海中圆柱壳的声辐射特性。研究发现吸声和刚性海底边界条件下圆柱壳的辐射声场有明显差别;可采用波导中点源格林... 根据声学边界元理论,本文在考虑海面和吸声海底的声反射作用基础上,对格林函数进行修正,建立波导域声辐射模型,并分析了浅海中圆柱壳的声辐射特性。研究发现吸声和刚性海底边界条件下圆柱壳的辐射声场有明显差别;可采用波导中点源格林函数预测圆柱壳的声辐射特性。结果表明边界反射作用随着圆柱壳离开海面或海底而减弱,随着场点离开圆柱壳而增强;且水深方向上声压呈周期性波动,其周期规律与海底边界类型无关。本文用声学点源的辐射叠加原理解释研究现象的产生机理,可为工程应用提供理论参考。 展开更多
关键词 边界元 浅海 圆柱壳 声辐射 吸声海底 波导 格林函数 点源
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坚果果壳中活性物质体外抗氧化活性研究进展 被引量:3
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作者 许莹莹 张宇 +2 位作者 肖康曼 范泽琨 李德海 《食品工业科技》 CAS CSCD 北大核心 2016年第14期385-388,394,共5页
作为坚果副产物的坚果果壳资源丰富,且富含多糖、多酚、黄酮等功能性成分,具有重要的开发价值。研究表明,坚果果壳提取物具有显著的抗氧化活性,可以清除体内自由基,减缓衰老,是开发天然抗氧化剂的优质资源。本文主要对坚果果壳中抗氧化... 作为坚果副产物的坚果果壳资源丰富,且富含多糖、多酚、黄酮等功能性成分,具有重要的开发价值。研究表明,坚果果壳提取物具有显著的抗氧化活性,可以清除体内自由基,减缓衰老,是开发天然抗氧化剂的优质资源。本文主要对坚果果壳中抗氧化活性物质体外抗氧化活性研究的重要性、各种研究方法的基本原理及应用情况进行了讨论,为坚果果壳抗氧化物质的开发利用提供参考。 展开更多
关键词 坚果果壳 活性物质 抗氧化活性 体外抗氧化评价
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