以青春文学为“常项”——描述中国当代文学的一种视角

青春文学是指处在青春期的作家所写的反映青春成长的文学作品。不同的时代、不同的社会,对待青春的态度各不相同,青春在不同的时代和社会也有不同的表现形态,从而构成了青春文学的多姿多彩。青春文学可以作为观察一段历史时期的文学特点的视野,甚至可以作为判断一段历史时期的文学内涵的标尺。

Regional magnetic anomaly fields:3D Taylor polynomial and surface spline models

We used data from 1960.0,1970.0,1980.0,1990.0,and 2000.0 to study the geomagnetic anomaly field over the Chinese mainland by using the three-dimensional Taylor polynomial（3DTP） and the surface spline（SS） models.To obtain the pure anomaly field,the main field and the induced field of the ionospheric and magnetospheric fields were removed from measured data.We also compared the SS model anomalies and the data obtained with Kriging interpolation（KI）.The geomagnetic anomaly distribution over the mainland was analyzed based on the SS and 3DTP models by transferring all points from 1960.0-1990.0 to 2000.0.The results suggest that the total intensity F anomalies estimated based on the SS and KI for each year are basically consistent in distribution and intensity.The anomalous distributions in the X-,Y-,and Z-direction and F are mainly negative.The 3DTP model anomalies suggest that the intensity in the X-direction increases from-100 nT to 0 nT with longitude,whereas the intensity in the Y-direction decreases from 400 nT to 20 nT with longitude and over the eastern mainland is almost negative.The intensity in the Z-direction and F are very similar and in most areas it is about-50 nT and higher in western Tibet.The SS model anomalies overall reflect the actual distribution of the magnetic field anomalies;however,because of the uneven distribution of measurements,it yields several big anomalies.Owing to the added altitude term,the 3DTP model offers higher precision and is consistent with KI.

Classification and Reduction of Generalized Thin Film Equations

Classification and reduction of the generalized fourth-order nonlinear differential equations arising from theliquid films are considered.It is shown that these equations have solutions on subspaces of the polynomial,exponential ortrigonometric form defined by linear nth-order ordinary differential equations with constant coefficients for n=4,...,9.Several examples of exact solutions are presented.

The Optimal Weighted Combinational Forecasting with Constant Terms

We propose a model based on the optimal weighted combinational forecasting with constant terms, give formulae of the weights and the average errors as well as a relation of the model and the corresponding model without constant terms, and compare these models. Finally an example was given, which showed that the fitting precision has been enhanced.

Nonlinear Mechanism of Bed Load Transport

From the group movement of the bed load within the bottom layer,details of the nonlinear dynamic characteristics of bed load movement are discussed in this paper.Whether the sediment is initiated into motion corresponds to whether the constant term in the equation is equal to zero.If constant term is zero and no dispersive force is considered,the equation represents the traditional Shields initiation curve,and if constant term is zero without the dispersive force being considered,then a new Shields curve which is much lower than the traditional one is got.The fixed point of the equation corresponds to the equilibrium sediment transport of bed load.In the mutation analysis,we have found that the inflection point is the demarcation point of breaking.In theory,the breaking point corresponds to the dividing boundary line,across which the bed form changes from flat bed to sand ripple or sand dune.Compared with the experimental data of Chatou Hydraulic Lab in France,the conclusions are verified.

Thirty years of chronic current account deficit 1972—2001: The case of Pakistan

Pakistan has been suffering from a chronic deficit in the current account for many decades. Current account deficit strengthens the foreign currency against the home currency which makes imports of good and services more expensive as compared to exports and causes devaluation of home currency. The main objective of this paper is to find out how the current account deficit is influenced by different economic factors. Our regression model’s estimated results indicate that the percentage change in the volume of imports, foreign direct investments and total consumption are positively correlated and, on the other hand, exports, workers remittance, growth in agriculture and manufacturing are negatively correlated with the current account balance of Pakistan during the observed period 1972-2001.

Value Distribution of a Class of Differential Polynomials

Let f（z） be a transcendental meromorphic function in the complex plane and a ≠0 be a constant, for any positive integer m, n, k, satisfy m ≥ nk＋n＋2, ψ= f^m ＋a（f^（κ））^n has infinitely many zeros. The corresponding normal criterion also is proved.

Strategic environmental assessment in China

In the past three decades, especially in recent years, the environment has unceasingly deteriorated with rapid development of Chinese economy, and the inherent limitations of conventional project EIA have come to light. Thus, to pursue a broader course of sustainable development, the Chinese government has attached more and more importance to SEA. Strategic Environmental Assessment （SEA） is a frontier subject in the field of Environmental Impact Assessment （EIA）. This article describes the current situation of SEA in China, discusses major problems with SEA, and then recommends improvements in the system. EIA Act of the People＇s Republic of China was promulgated which explicitly provides SEA is required in regional and sector plans and programs. In order to promote comprehensive development of SEA, a lot of work has been done by SEPA. Some SEA ＂experiments＂ have been implemented, and some research has been conducted on the topic in China. But SEA as applied today in China is confronted with a host of methodological and institutional limitations. Moreover, public participation is often extremely limited, because the system restricts public participation. Policies and strategies are kept secret from the public. Most of the research has been focused on the concept, theory, and framework of SEA. Comprehensive application of SEA in China has yet to occur, and only a limited number of case studies are available. We believe SEA can be improved by the following recommendations： dividing SEA into two stages, formulating legislation to safeguard the funds for SEA, guiding actively the public to participate in SEA, completing basic data bank about SEA, and setting up Hall for Workshop of Meta-synthetic Engineering for SEA.

The Degenerate Form of the Adomian Polynomials in the Power Series Method for Nonlinear Ordinary Differential Equations

In this paper, we propose a new variation of the Adomian polynomials, which we call the degenerate Adomian polynomials, for the power series solutions of nonlinear ordinary differential equations with nonseparable nonlinearities. We establish efficient algorithms for the degenerate Adomian polynomials. Next we compare the results by the Adomian decomposition method using the classic Adomian polynomials with the results by the Rach-Adomian-Meyers modified decomposition method incorporating the degenerate Adomian polynomials, which itself has been shown to be a confluence of the Adomian decomposition method and the power series method. Convergence acceleration techniques including the diagonal Pade approximants are considered, and new numeric algorithms for the multistage decomposition are deduced using the degenerate Adomian polynomials. Our new technique provides a significant advantage for automated calculations when computing the power series form of the solution for nonlinear ordinary differential equations. Several expository examples are investigated to demonstrate its reliability and efficiency.

Application of the Generalized Differential Quadrature Method in Solving Burgers' Equations

The aim of this paper is to obtain numerical solutions of the one-dimensional,two-dimensional and coupled Burgers' equations through the generalized differential quadrature method(GDQM).The polynomial-based differential quadrature(PDQ) method is employed and the obtained system of ordinary differential equations is solved via the total variation diminishing Runge-Kutta(TVD-RK) method.The numerical solutions are satisfactorily coincident with the exact solutions.The method can compete against the methods applied in the literature.

A New Differential Quadrature Methodology Based on Bernstein Polynomials for Solving the Equations Governing the Unsteady Flow of a Polytropic Gas

Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numerical solutions of the governing equations of unsteady two-dimensional flow of a polytropic gas are investigated. The numerical results reveal that the new technique is very effective and gives high accuracy, good convergence and reasonable stability.

Constant terms of spherical Eisenstein series on quasi-split unitary groups

In this note, we prove a formula which expresses the constant term of the spherical Eisenstein series on a quasi-split unitary group as a linear combination of spherical Eisenstein series on smaller unitary groups.

ON THE HYPER ORDER OF SOLUTIONS OF HIGHER ORDER DIFFERENTIAL EQUATIONS

The author investigates the hyper order of solutions of the higher order linear equation, andimproves the results of M. Ozawa[15], G. Gundersen[6] and J. K. Langley[12].

A Triangular Decomposition Algorithm for Differential Polynomial Systems with Elementary Computation Complexity

In this paper, a new triangular decomposition algorithm is proposed for ordinary differential polynomial systems, which has triple exponential computational complexity. The key idea is to eliminate one algebraic variable from a set of polynomials in one step using the theory of multivariate resultant. This seems to be the first differential triangular decomposition algorithm with elementary computation complexity.

Global Asymptotics of Orthogonal Polynomials Associated with a Generalized Freud Weight

In this paper, the authors consider the asymptotic behavior of the monic polynomials orthogonal with respect to the weight function w（x） = /x/2αe-（x4＋tx2）, x ∈R, where α is a constant larger than - 1/2 and t is any real number. They consider this problem in three separate cases： （i） c 〉 -2, （ii） c = -2, and （iii） c 〈 -2, where c ：= tN-1/2 is a constant, N = n ＋ a and n is the degree of the polynomial. In the first two cases, the support of the associated equilibrium measure μ is a single interval, whereas in the third case the support of μt consists of two intervals. In each case, globally uniform asymptotic expansions are obtained in several regions. These regions together cover the whole complex plane. The approach is based on a modified version of the steepest descent method for Riemann-Hilbert problems introduced by Deift and Zhou （1993）.