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海底薄地层和硬地层声速测量方法的研究(射线参数法和折射法分析) 被引量:3
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作者 张叔英 《声学学报》 EI CSCD 北大核心 1991年第3期187-198,共12页
应用T^2-X^2法测量海底薄地层和硬地层的声速常常不能得到满意的结果。为此,有必要在一个由声源和拖曳水听器阵组成的声速测量系统中设置接射线参数法和折射法测量海底地层声速的处理功能。本文从这两种方法的测量原理出发,着重研究了... 应用T^2-X^2法测量海底薄地层和硬地层的声速常常不能得到满意的结果。为此,有必要在一个由声源和拖曳水听器阵组成的声速测量系统中设置接射线参数法和折射法测量海底地层声速的处理功能。本文从这两种方法的测量原理出发,着重研究了地层回波时距数据的处理方法,以及由各种因素(如回波时间随机抖动和地层界面倾斜角不确定性等)所引起的声速测量误差等问题。射线参数法和折射法测量声速的数据处理和运算过程已经用TURBO-PASCAL语言编程,并通过对典型实例的模拟计算作了验证。 展开更多
关键词 海底 地层 声速 射线参数法 折射
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用射线参数法遥测浅海沉积层声的特性 被引量:1
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作者 林俊轩 王恕铨 +1 位作者 杨振华 惠少华 《山东海洋学院学报》 1987年第1期63-70,共8页
本文根据射线参数法测量了浅海(水深约40米)沉积层中的声速与层厚。实验中采用爆炸声源,两个水听器,其中一个固定于声源附近,用以计算爆炸开始时间,另一个用于在不同水平距离接收海底及沉积层下界面的反射信号。用磁带记录仪和示波器配... 本文根据射线参数法测量了浅海(水深约40米)沉积层中的声速与层厚。实验中采用爆炸声源,两个水听器,其中一个固定于声源附近,用以计算爆炸开始时间,另一个用于在不同水平距离接收海底及沉积层下界面的反射信号。用磁带记录仪和示波器配以照相记录仪两种方式记录。所得沉积层中声速值与根据底质取样所得声速值基本一致。 展开更多
关键词 射线参数法 浅海沉积层 声速 层厚遥测 实验方
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参数法实时遥测液态沉积层的声学特性
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作者 王辉照 林俊轩 崔国林 《水运工程》 北大核心 1995年第1期3-7,共5页
根据射线参数法原理,利用信号处理机(7T18S)进行实时采样,自动判读信号后进行运算得到层介质(淤泥、粘土、亚粘土)的声速和厚度值。利用水池模拟实验对该方案的可行性作了验证,1985年9月在黄河口海区进行试验,结果表... 根据射线参数法原理,利用信号处理机(7T18S)进行实时采样,自动判读信号后进行运算得到层介质(淤泥、粘土、亚粘土)的声速和厚度值。利用水池模拟实验对该方案的可行性作了验证,1985年9月在黄河口海区进行试验,结果表明该海区的沉积层介质为粘土淤泥。 展开更多
关键词 射线参数法 海底 沉积层 层介质 声学特性
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Double-Parameter Solutions of Projective Riccati Equations and Their Applications 被引量:1
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作者 WANG Ming-Liang LI Er-Qiang LI Xiang-Zheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第1期1-9,共9页
The purpose of the present paper is twofold. First, the projective Riccati equations (PREs for short) are resolved by means of a linearized theorem, which was known in the literature. Based on the signs and values o... The purpose of the present paper is twofold. First, the projective Riccati equations (PREs for short) are resolved by means of a linearized theorem, which was known in the literature. Based on the signs and values of coeffcients of PREs, the solutions with two arbitrary parameters of PREs can be expressed by the hyperbolic functions, the trigonometric functions, and the rational functions respectively, at the same time the relation between the components of each solution to PREs is also implemented. Second, more new travelling wave solutions for some nonlinear PDEs, such as the Burgers equation, the mKdV equation, the NLS^+ equation, new Hamilton amplitude equation, and so on, are obtained by using Sub-ODE method, in which PREs are taken as the Sub-ODEs. The key idea of this method is that the travelling wave solutions of nonlinear PDE can be expressed by a polynomial in two variables, which are the components of each solution to PREs, provided that the homogeneous balance between the higher order derivatives and nonlinear terms in the equation is considered. 展开更多
关键词 projective Riccati equations linearized theorem homogeneous balance Sub-ODE method travelling wave solutions nonlinear PDE
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Crystallographic Parameters and Band Gap of CdSxSe1-x Mixed Crystals
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作者 Abdullah A. Al-Bassam Usamh A. Elani 《Journal of Energy and Power Engineering》 2014年第4期770-774,共5页
Crystals of CdSxSe1-x alloys have been grown from the vapour phase. Some of the physical properties, such as lattice parameters, crystal structure and x-rays data of CdSxSe1-x alloys were determined using x-ray diffra... Crystals of CdSxSe1-x alloys have been grown from the vapour phase. Some of the physical properties, such as lattice parameters, crystal structure and x-rays data of CdSxSe1-x alloys were determined using x-ray diffractometry. X-ray diffractometry has shown that CdS-CdSe mixed crystals had the wurtzite structure for all compositions between CdS and CdSe. The lattice parameters (both a and c) were found to show a linear dependence with composition. The dependence of the lattice parameters of a and c on composition can be expressed as: a(x) = 4.165 + 0.16x; c(x) = 6.713 + 0.27x. The variation of band gap with composition was determined for these samples from optical absorption measurements, which showed that the band gap varied smoothly and monotonically, but not linearly over the composition range typical results were found between 2.42-1.74 eV at room temperature. 展开更多
关键词 Thin films mixed crystals lattice parameter SEMICONDUCTORS devices.
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