用归一相约法求有条件的分式值

给出一定的条件，然后探索在这一条件下求某分式的值的问题，是初中代数的内容，解法较多，灵活性较大，技巧性较强。本文拟介绍运用归一相约法求有条件的分式值。

Similarity Reductions of(2+1)-Dimensional Multi-component Broer-Kaup System

Painleve property of the （2＋1）-dimensional multi-component Broer-Kaup （BK） system is considered by using the standard Weiss Kruskal approaches. Applying the Clarkson and Kruskal （CK） direct method to the （2＋1）- dimensional multi-component BK system, some types of similarity reductions are obtained. By solving the reductions, one can get the solutions of the （2＋1）-dimensional multi-component BK system.

Symmetry Reductions and Exact Solutions of Blaszak-Marciniak Four-Field Lattice Equation

Applying the Lie group method to the differential-difference equation, the Lie point symmetry of Blaszak- Marciniak four-field Lattice equation is obtained. Using the obtained symmetry, the similarity reduction equations of Blaszak-Marciniak four-field Lattice equation are derived. Solving the reduction, we get the solution of Blaszak-Marciniak four-field Lattice equation which not only recovers one of the solutions obtained by Ma and Hu [J. Math. Phys. 40 （1999） 6071] but also has the singularity when we choose the arbitrary constants accurately.

Similarity Reductions and Exact Solutions of a Coupled Korteweg de Vries System

For a special coupled Korteweg de Vries （KdV） system, its similarity solutions and reduction equations are obtained by the Clarkson and Kruskal＇s direct method. In addition, its new explicit soliton solutions and traveling wave solutions are found by the deformation and mapping method.

Approximate Homotopy Symmetry Reduction Method:Infinite Series Reductions to Kawahara Equation

The Kawahara equation is studied through the approximate homotopy symmetry method. Under this method we get the similarity reduction solutions of the Kawahara equation, leading to the corresponding homotopy series solutions. Furthermore, the similarity solutions of the corresponding reduced linear ordinary differential equations are also considered.

Role of Researcher/Academia in Making UK Low Carbon Policy

This study focuses on the role of researcher/academia in making low carbon policy in the UK. UK researchers and universities enjoy relatively high degree of independence of their research from the government due to its statute that guarantees its independence （＂The Haldene Principle＂）. In addition, there was a recent movement for evidence-based policy in the UK, which requires more economic and scientific robustness, therefore role of engineers and social scientists are increasingly important. In particular, social science will have a greater role in changing people＇s behavior with high level of uncertainty. UK businesses have played a leading role to move forward the climate policy such as UKETS （United Kingdom Emissions Trading Scheme） as well as low carbon policy. The regular communication and consultation is a crucial basis for making integrated policy, which involves wide range of stakeholders. The legally binding targets set out by Climate Change Act 2008 required structural change of the government to implement the necessary policies and measures especially by integrating climate and energy policy.

Instantaneous phase inversion based on an unwrapping algorithm

The full-waveform inversion method is a high-precision inversion method based on the minimization of the misfit between the synthetic seismograms and the observed data.However,this method suffers from cycle skipping in the time domain or phase wrapping in the frequency because of the inaccurate initial velocity or the lack of low-frequency information.furthermore,the object scale of inversion is affected by the observation system and wavelet bandwidth,the inversion for large-scale structures is a strongly nonlinear problem that is considerably difficult to solve.In this study,we modify the unwrapping algorithm to obtain accurate unwrapped instantaneous phase,then using this phase conducts the inversion for reducing the strong nonlinearity.The normal instantaneous phases are measured as modulo 2π,leading the loss of true phase information.The path integral algorithm can be used to unwrap the instantaneous phase of the seismograms having time series and onedimensional(1 D)signal characteristics.However,the unwrapped phase is easily affected by the numerical simulation and phase calculations,resulting in the low resolution of inversion parameters.To increase the noise resistance and ensure the inversion accuracy,we present an improved unwrapping method by adding an envelope into the path integral unwrapping algorithm for restricting the phase mutation points,getting accurate instantaneous phase.The objective function constructed by unwrapping instantaneous phase is less affected by the local minimum,thereby making it suitable for full-waveform inversion.Further,the corresponding instantaneous phase inversion formulas are provided.Using the improved algorithm,we can invert the low-wavenumber components of the underneath structure and ensure the accuracy of the inverted velocity.Finally,the numerical tests of the 2 D Marmousi model and 3 D SEG/EAGE salt model prove the accuracy of the proposed algorithm and the ability to restore largescale low-wavenumber structures,respectively.

Combining ODM and OCL in ontology verification

In order to automatically find and conveniently rectify the structural conflicts appearing in a new ontology model version after a series of ontology evolution,we propose an ontology model verification approach,in which the object constraint language (OCL) and an ontology definition meta-model (ODM) are used to complete the ontology verification.The ODM is composed of the ontology related elements and the definition rule related elements.The OCL is employed to describe the elements in the ontology definition meta-model:OCL extension for the ontology related elements,and OCL extension for the ontological design patterns.All of the above OCL rules will describe the constraint relationships between ontology elements.Associated with an example,the application of the ontology model verification approach based on OCL and ODM is introduced.Consequently,the conflicts happened in the ontology changing and evolution can be easily verified and rectified through this approach.

初中数学竞赛求值题常用的解法

近年来国内外的初中数学竞赛题,对于求值题目日益受到参加竞赛的师生的关注.这类题目灵活有变,且解答技巧性较强.本文试图通过列解若干数学竞赛试题,总结、归类解答的一些常用方法和技巧,并配备有相应的练习題(限于篇幅,每类型仅举一例),谨供参考.