投影制图中的逆射与相交

为了更有效地训练和提高学生的空间思维能力和三维构形能力,在画法几何与投影制图的教学过程中,有必要增加一个从二维向三维转换的教学环节,即从几何元素的二维投影表达出发,实现三维形体的重建和三维环境下的定位、测量。在画法几何与投影制图的教学过程中,应用作者开发的图形教学软件Projector,操作者可以方便地从空间点、线、面、体,得到平面投影,也可以从已知平面投影出发,求解空间几何问题。

高维射影空间中的逆射与配极

本文研究了ｎ维射影空间中的逆射变换的确定、性质及其一类特殊变换——配极变换的性质．从射影几何角度证明了如下结论：在Ｐｎ中对非退化的二次曲面Σ：∑ｎ＋１ｉ，ｊ＝１ａｉｊｘｉｘｊ＝０，ａｉｊ＝ａｊｉ，｜ａｉｊ｜≠０．经过适当的射影变换，即选择恰当的自共轭ｎ＋１面体作为参考坐标ｎ＋１面体时便可把二次曲面方程化简为标准式：ｂ１ｘ２１＋ｂ２ｘ２２＋…

投影制图中的新概念——逆射与相交

为了更有效地训练和提高学生的空间思维能力和三维构形能力,在画法几何与投影制图的教学过程中,有必要增加一个从二维向三维转换的教学环节,即从几何元素的二维投影表达出发,实现三维形体的重建和三维环境下的定位、测量。在画法几何与投影制图的教学过程中,应用作者开发的图形教学软件Projector,操作者可以方便地从空间点、线、面、体,得到平面投影,也可以从已知平面投影出发,求解空间几何问题。

基于逆绕射抛物方程法定位大气波导环境下的发射源

无源定位是近来的一个研究热门课题,逆绕射抛物方程法(IDPELS)能对发射源进行定位;但是传统IDPELS对复杂环境的处理能力有限,影响了其定位的精度。由于大气波导对电波传播的影响很大直接降低了定位精度,所以提出了逆绕射抛物方程法对大气波导的处理方法。对大气波导环境发射源定位进行了研究,给出了仿真结果并分析了大气波导对定位精度的影响;结果表明:考虑大气波导环境提高了传统IDPELS的定位精度,增大了IDPELS在复杂环境下的应用范围。

他者反立与身体意向性逆射之路——从海德格尔经梅洛—庞蒂至列维纳斯

通过对纯粹自我回溯进行批判,海德格尔将胡塞尔的意识意向性转变为身体意向性。可这种生存哲学在风靡法国的同时亦遭遇唯我论的质疑。随着梅洛—庞蒂和列维纳斯不断对他者地位进行提升,身体意向性也逐步实现了向主体的逆射。这一结果批判且否定了西方传统哲学的暴力内涵,并在一定程度上为伦理学、政治哲学以及形而上学开辟了新的方向。

粘弹性介质中逆散射问题的求解方法

本文讨论了一维粘弹性介质中的逆散射问题,给出了两种反演粘弹性介质松弛模量的方法。这两种方法只利用了介质层一侧波的反射数据,其中一种方法只需已知一个走时来回时间内的反射数据就可以确定介质的松弛模量在任意时刻的值。文中最后给出了数值算例,可以看出,数值反演的结果与初始给定的松弛模量吻合得很好。

Conjugate gradient and cross-correlation based least-square reverse time migration and its application

Although conventional reverse time migration can be perfectly applied to structural imaging it lacks the capability of enabling detailed delineation of a lithological reservoir due to irregular illumination. To obtain reliable reflectivity of the subsurface it is necessary to solve the imaging problem using inversion. The least-square reverse time migration （LSRTM） （also known as linearized refleetivity inversion） aims to obtain relatively high-resolution amplitude preserving imaging by including the inverse of the Hessian matrix. In practice, the conjugate gradient algorithm is proven to be an efficient iterative method for enabling use of LSRTM. The velocity gradient can be derived from a cross-correlation between observed data and simulated data, making LSRTM independent of wavelet signature and thus more robust in practice. Tests on synthetic and marine data show that LSRTM has good potential for use in reservoir description and four-dimensional （4D） seismic images compared to traditional RTM and Fourier finite difference （FFD） migration. This paper investigates the first order approximation of LSRTM, which is also known as the linear Born approximation. However, for more complex geological structures a higher order approximation should be considered to improve imaging quality.

关于同调代数中几个问题的注记

阐述了态射广义逆及其模的性质 ,给出了几个猜想 ,分析了投射模、平坦模。

~ Transform Demonstration of Dark Soliton Solutions Found by Inverse Scattering

One of the basic problems about the inverse scattering transform for solving a completely integrable nonlinear evolutions equation is to demonstrate that the Jost solutions obtained from the inverse scattering equations of Cauchy integral satisfy the Lax equations. Such a basic problem still exists in the procedure of deriving the dark soliton solutions of the NLS equation in normal dispersion with non-vanishing boundary conditions through the inverse scattering transform. In this paper, a pair of Jost solutions with same analytic properties are composed to be a 2 × 2 matrix and then another pair are introduced to be its right inverse confirmed by the Liouville theorem. As they are both 2 × 2 matrices, the right inverse should be the left inverse too, based upon which it is not difficult to show that these Jost solutions satisfy both the first and second Lax equations. As a result of compatibility condition, the dark soliton solutions definitely satisfy the NLS equation in normal dispersion with non-vanishing boundary conditions.

Solving Non-Isospectral mKdV Equation and Sine-Gordon Equation Hierarchies with Self-Consistent Sources via Inverse Scattering Transform

N-soliton solutions of the hierarchy of non-isospectral mKdV equation with self-consistent sources andthe hierarchy of non-isospectral sine-Gordon equation with self-consistent sources are obtained via the inverse scatteringtransform.

Nested Bethe Ansatz for Spin Ladder Model with Open Boundary Conditions

The nested Bethe ansatz (BA) method is applied to find the eigenvalues and the eigenvectors of the transfer matrix for spin-ladder model with open boundary conditions. Based on the reflection equation, we find the general diagonal solution, which determines the generalboundary interaction in the Hamiltonian. We introduce the spin-ladder model with open boundary conditions. By finding the solution K± of the reflection equation which determines the nontrivial boundary terms in the Hamiltonian, we diagonalize the transfer matrix of the spin-ladder model with open boundary conditions in the framework of nested BA.

INVERSE KINEMATICS FOR A 6 DOF MANIPULATOR BASED ON NEURAL NETWORK

A methodology is presented whereby a neural network is used to learn the inverse kinematic relationships of the position and orientation of a six joint manipulator. The arm solution for the orientation of a manipulator using a self organizing neural net is studied in this paper. A new training model of the self organizing neural network is proposed by thoroughly studying Martinetz, Ritter and Schulten′s self organizing neural network based on Kohonen′s self organizing mapping algorithm using a Widrow Hoff type error correction rule and closely combining the characters of the inverse kinematic relationship for a robot arm. The computer simulation results for a PUMA 560 robot show that the proposed method has a significant improvement over other methods documented in the references in self organizing capability and precision by training process.

CHARACTER OF RETROREFLECTOR’S LIGHT FIELD’S ENERGY DISTRIBUTION AND ITS MEASURING TECHNOLOGY

The formation of the retroreflected light field is introduced in the paper and the components of the retroreflected light field are analyzed.Furthermore,a deep analysis of the factors affecting energy distribution of the retroreflected light,such as design deviation,angle of incidence,was made.The simulation of the retroreflected light field was done.Recommendation is made in detail on both the energy distribution of the retroreflected light field at different working distances and the energy distribution of the retroreflected light field at a short distance when the diverging light comes.At last,two kinds of measuring instrument for the retroreflector are introduced,one is the long tunnel measuring instrument,the other is the minitype measuring instrument based on the character of the retroreflector when the diverging light comes.

Demonstration of Inverse Scattering Transform for DNLS Equation

Since the Jost solutions of the DNLS equation does not tend to the free Jost solutioins as ｜λ｜→∞, the usual inverse scattering transform （IST） must be revised. Beside the Kaup and Newell＇s approach, we propose a simple revision in constructing the equations of IST, where the usual Zakharov-Shabat kern is revised by multiplying λ^-2 or λ^-1. To justify the revision we show that the Jost solutions obtained do satisfy the pair of compatibility equations.

Local Gas Phase Flow Characteristics of a Gas-Liquid-Solid Three-Phase Reversed Flow Jet Loop Reactor

The local gas-phase flow characteristics such as local gas holdup(εg), local bubble velocity (V_b) and local bubble mean diameter(d_b) at a specified point in a gas-liquid-solid three-phase reversedflow jet loop reactor was experimentally investigated by a five-pointconductivity probe. The effects of gas jet flow rate, liquid jet flowrate, solid loading, nozzle diameter and axial position on the localεg, V_b and d_b profiles were discussed. The presence of solids atlow solid concentrations not only increased the local εg and V_b,but also decreased the local d_b. The optimum solid loading for themaximum local εg and V_b together with the minimum local d_b was0.16×10^-3 m^3, corresponding to a solid volume fraction ε_S＝2.5/100.

Lump Solutions of Kadomtsev-Petviashvili I Equation in Non-uniform Media

N-lump solutions of the Kadomtsev-Petviashvili I equation in non-uniform media are derived through the inverse scattering transform. The obtained solutions describe lump waves with time-dependent amplitudes and velocities. Dynamics of l-lump wave and interactions of two lump wave are illustrated.

Inverse Gaussian-beam common-reflection-point-stack imaging in crosswell seismic tomography

To solve problems in small-scale and complex structural traps,the inverse Gaussian-beam stack-imaging method is commonly used to process crosswell seismic wave reflection data.Owing to limited coverage,the imaging quality of conventional ray-based crosswell seismic stack imaging is poor in complex areas;moreover,the imaging range is small and with sever interference because of the arc phenomenon in seismic migration.Thus,we propose the inverse Gaussian-beam stack imaging,in which Gaussian weight functions of rays contributing to the geophones energy are calculated and used to decompose the seismic wavefield.This effectively enlarges the coverage of the reflection points and improves the transverse resolution.Compared with the traditional VSP–CDP stack imaging,the proposed methods extends the imaging range,yields higher horizontal resolution,and is more adaptable to complex geological structures.The method is applied to model a complex structure in the K-area.The results suggest that the wave group of the target layer is clearer,the resolution is higher,and the main frequency of the crosswell seismic section is higher than that in surface seismic exploration The effectiveness and robustness of the method are verified by theoretical model and practical data.

Generalized Inverses of Matrices over Rings

Let R be a ring, * be an involutory function of the set of all finite matrices over R. In this paper, necessary and sufficient conditions are given for a matrix to have a (1,3)-inverse, (1,4)-inverse, or Moore-P enrose inverse, relative to *. Some results about generalized inverses of matrices over division rings are generalized and improved.

Application of Eliminating Zero-order Diffraction Light in Wavefront Reconstruction of Inverse Diffraction Computation

According to the Collins’ formula and its inverse diffraction computation,this paper presents an algorithm for reconstructing the object wavefront of a numerical holograph.To improve the quality of wavefront reconstruction,a technique of eliminating the zero-order diffraction light is introduced,which is achieved by subtraction of two intensities of the interference patterns.The computer simulation and image processing show that the method of eliminating the zero-order diffraction beam can be applied to the wavefront reconstruction of inverse diffraction computation.

Twenty-five Cases of Obstinate Hiccup Treated by Point Injection at Tianding

From 1997 to 2000, the author treated 25 cases of obstinate hiccup by injecting chlorpromazine and 654-2 injection at Tianding (LI 17), with satisfactory therapeutic results as reported in the following.