开展工程设计监理的对策

工程设计监理势在必行。怎样从实践上展开设计监理有许多问题需要研究和探索。章分析了工程设计监理的现状和特点，并据以提出开展工程设计监理的对策。这对工程建设监理在工程项目建设中的全方位实施，有一定的意义。     

由椭圆偏微分方程所支配的混凝土坝基渗流系统的最优线态控制

本文从混凝土坝基渗流控制问题中抽象出由椭圆偏微分方程混杂问题所支配的系统的最优线态控制问题 .给出了最优线态控制的存在唯一性 ,得到了控制为最优的充分必要条件及最优性组     

Understanding and supporting teacher horizon knowledge around limits: a framework for evaluating textbooks for teachers

As part of recent scrutiny of teacher capacity, the question of teachers’ content knowledge of higher level mathematics emerges as important to the field of mathematics education. Elementary teachers in North America and some other countries tend to be subject generalists, yet it appears that some higher level mathematics background may be appropriate for teachers. An initial examination of a small sample of textbooks for teachers suggested the existence of a wide array of treatments and depth and quality of mathematics coverage. Based on the literature, a new framework was created to assess the mathematical quality of treatments for both specialized knowledge and horizon knowledge in mathematics textbooks for teachers. The framework was tested on a sample topic of the circle area formula derivation, chosen because it draws heavily on both specialized and horizon knowledge. The framework may contribute to similar analyses of other topics in a broader range of resources, in the overall quest to better describe the details of what constitutes appropriate mathematics horizon knowledge for teachers.     

Maximum Waring Ranks of Monomials and Sums of Coprime Monomials

We show that monomials and sums of pairwise coprime monomials in four or more variables have Waring rank less than the generic rank, with a short list of exceptions. We asymptotically compare their ranks with the generic rank.     

On nonuniqueness of solutions to elliptic equations for probability measures

We consider the set of all probability measures μ on Rd satisfying an elliptic equation L^∗μ=0 in the weak worm. We give sufficient conditions in order that this set contains at least two different elements. We also construct new examples of nonuniqueness for such equations.     

A Continuous Planar Map With Many Periodic Points

The existence and structure of periodic orbits of the discrete delayed logistic equation x_n=;1=rx_n(1?x_n?1) is studied. In the phase plane (x,y)=(x_n?1,x_n), the corresponding continuous planar map is F_r(x,y)=(y, ry(1?x)). The Birkhoff-Smale theorem for infinitely many periodic points in the neighborhood of a homoclinic point of a differentiable map is appropriately modified for the example; the proof resembles the geometric proof of Birkhoff in two dimensions. Related numerical work is included, and implications of the results in terms of a model for population growth are discussed.     

积分中值定理中间点比较及有关平均不等式

中值定理中间点是区间端点的平均.设f (x)、g(x)在同一区间[a,b]内严格单调并可积,p(x)、q(x)恒正可积,按积分中值定理各有唯一的中间点ξf ,p(a,b)和ξg,q(a,b) .当f递增(减)且f (g- 1)凸(凹)时,有ξg,p(a,b) <ξf,p(a,b) ;当p(x)q(x) 递增(减)且q(x) ∫bap(x) dx >( <) 0时,有ξf,q(a,b) <ξf ,p(a,b) .由此可证明和发现一系列有关平均的不等式.     

Estimates of

We extend a result of Ramaré and Rumely, 1996, about the Chebyshev function in arithmetic progressions. We find a map such that and 0)}$">, whereas is a constant. Now we are able to show that, for ,

and, for ,

\frac{x}{2\ln x}.\end{displaymath}">

     

Error estimation of grain distribution function recovery for dependent orientations with allowance for grain sizes

The effect of the kernel on the smoothing of orientations in a kernel method was studied, and the influence of dependent orientations and the grain sizes on the resulting distribution was analyzed. Discrete central normal distributions on the group SO(3) were smoothed by the kernel method. This problem is motivated by the development of experimental tools for studying the texture of polycrystalline materials, especially electron microscopy, which makes it possible to measure the orientations of individual grains.     

On the Multiplicity of Solutions of Semilinear Equations

We study uniqueness and exact multiplicity of solutions of semilinear equations for both balls and annular domains. We assume the annular domains to be “thin ”, but allow them to be wider than in the previous works.     

An upper bound for permanents of nonnegative matrices

A recent conjecture of Caputo, Carlen, Lieb, and Loss, and, independently, of the author, states that the maximum of the permanent of a matrix whose rows are unit vectors in lp is attained either for the identity matrix I or for a constant multiple of the all-1 matrix J.The conjecture is known to be true for p=1 (I) and for p?2 (J).We prove the conjecture for a subinterval of (1,2), and show the conjectured upper bound to be true within a subexponential factor (in the dimension) for all 1<p<2. In fact, for p bounded away from 1, the conjectured upper bound is true within a constant factor.     

Principal components in the nonnormal case: The test of equality of Q roots

The limiting distribution of the likelihood ratio statistic W_q for testing the hypothesis of equality of q characteristic roots of a covariance matrix is studied in the case of nonnormal populations. It is shown, both theoretically and empirically, that the limiting distribution of W_q is not robust to departures from normality and that W_q cannot be used for nonnormal populations with long tails. For the class of elliptical populations the limiting distribution of W_q can be expressed in close form. A corrected test statistic, W_q^*, is proposed that can be used in principal component analysis when sampling from elliptical populations.     

提取医用黄腐酸的优化方案

本文介绍如何用正交试验法选择提取医用黄腐酸的最优方案 ,使提取出的医用黄腐酸达到最佳提取率 ,并符合国家药典标准     

A Quantitative Regularity Estimate for Nonnegative Supersolutions of Uniformly Parabolic Equations

This note establishes an interior quantitative lower bound for nonnegative supersolutions of fully nonlinear uniformly parabolic equations. The result may be interpreted as a quantitative version of a growth lemma established by Krylov and Safonov for nonnegative supersolutions of linear uniformly parabolic equations in nondivergence form. Our approach is different, and follows from an application of a reverse Holder inequality. The result is the parabolic analogue of an elliptic regularity estimate established by Caffarelli, Souganidis, and Wang in the stochastic homogenization of fully nonlinear uniformly elliptic equations.     

The Atiyah-Jones conjecture for rational surfaces

We show that if the Atiyah-Jones conjecture holds for a surface X, then it also holds for the blow-up of X at a point. Since the conjecture is known to hold for P² and for ruled surfaces, it follows that the conjecture is true for all rational surfaces.     

Secondary mathematics teachers’ meanings for measure,slope, and rate of change

This article reports an investigation of 251 high school mathematics teachers’ meanings for slope, measurement, and rate of change. The data was collected with a validated written instrument designed to diagnose teachers' mathematical meanings. Most teachers conveyed primarily additive and formulaic meanings for slope and rate of change on written items. Few teachers conveyed that a rate of change compares the relative sizes of changes in two quantities. Teachers’ weak measurement schemes were associated with limited meanings for rate of change. Overall, the data suggests that rate of change should be a topic of targeted professional development.     

New inversion formula for the solution to an inverse diffraction problem

For the solution to the basic problem of quantitative texture analysis, a new inversion formula is derived that makes use of the generating function for Legendre polynomials.