关于“不动点定理与不动点逼近”一文的注记

本文讨论度量空间中一类映象不动点的存在性及迭代序列的收敛性,在更广泛的情形下回答了张大中文中提出的问题。     

六探"元素立体周期律"--科学由"潜"到"显"的磨难

本文说明科学的探索是永恒的主题,元素周期律也不例外,认为元素周期律仍要发展.以科学由"潜"到"显"存在的磨难事例,论述"元素立体周期律"发展中也存在磨难.     

NONTRIVIAL PERIODIC SOLUTIONS OF A SEMILINEAR WAVE EQUATION WITHOUT ASSUMPTION OF MONOTONICITY

In references,some authors have succeeded in obtaining existence re-sults of the superlinear wave equation without the assumption of monotonicity forthe nonlinear term.In this paper,we present existence results for this problem byusing local linking idea and improve some previous results.     

An appraisal of Mendeleev’s contribution to the development of the periodic table

Historians and philosophers of science generally conceptualize scientific progress to be dichotomous, viz., experimental observations lead to scientific laws, which later facilitate the elaboration of explanatory theories. There is considerable controversy in the literature with respect to Mendeleev’s contribution to the origin, nature, and development of the periodic table. The objectives of this study are to explore and reconstruct: a) periodicity in the periodic table as a function of atomic theory; b) role of predictions in scientific theories and its implications for the periodic table; and c) Mendeleev’s contribution: theory or an empirical law? The reconstruction shows that despite Mendeleev’s own ambivalence, periodicity of properties of chemical elements in the periodic table can be attributed to the atomic theory. It is argued that based on the Lakatosian framework, predictions (novel facts) play an important role in the development of scientific theories. In this context, Mendeleev’s predictions played a crucial role in the development of the periodic table. Finally, it is concluded that Mendeleev’s contribution can be considered as an “interpretative” theory which became “explanatory” after the periodic table was based on atomic numbers.     

具加权的半线性周期种群系统的最优边界控制

讨论具有年龄和加权的半线性周期种群系统的最优边界控制问题.利用偏微分方程和泛函分析等理论证明了系统最优控制的存在性和控制为最优的必要条件,并得到了确定最优控制的最优性组,体现出加权总规模对周期种群动态过程的实际的影响,更具有实际意义.     

具有时变位势的二阶方程的周期解

本文运用相平面方法，分析了具有时变位势和二阶方程的解的弹性性质，由此并应用Ｃａｐｉｅｔｔｏ，Ｍａｗｈｉｎ和Ｚａｎｏｌｉｎ的牢来得到的一个延拓定理，证明了具有时变位势的二队方程的周期解的存在性。     

鲍林近似能级图的新认识

鲍林近似能级图对于理论化学的研究具有很重要的意义。但是,由于它的规律性不是那么明显,因而使用不是太方便。本人通过重新的排列,将复杂的鲍林近似能级图简便化,规律化,实用化。在将方便其与元素周期律联系起来的同时,也大大方便了元素对应其电子、价电子排布式的书写。运用这张能级图,还可以快速地将某个原子的原子序数与其所对应的元素周期表的位置相互联系对应起来,方便计算。     

具有两个偏差变元的Duffing型方程周期解的存在唯一性

利用重合度理论研究了一类具有两个偏差变元的Duffing型方程x′′ g1(t,x(t?τ1(t))) g2(t,x(t?τ2(t)))=p(t).获得了该方程T-周期解存在唯一性的若干新结论.     

Seasonality in large-scale macroeconometric models

Macroeconomic indicators are typically appraised in seasonally adjusted form, and forecasts are often presented in a similar way (as annual changes, for example). Moreover, the quarterly macroeconomic models used in forecasting are commonly estimated from seasonally adjusted data. Nevertheless, these models can generate forecasts with seasonal patterns, and this paper assesses the cause and cure of this phenomenon. It is found that forecast seasonality is induced by seasonality in the various inputs: exogenous variables, residual adjustments, the dynamic specification of certain equations, and annual changes in policy variables. Series changing annually but observed quarterly are termed ‘intercalated series’, and are simple examples of periodic processes. Forecast seasonality can be removed by appropriate adjustment of all these inputs. Models containing explicit future expectations variables solved in a model-consistent manner are also considered: numerical sensitivity to the terminal quarter may result from terminal conditions that require adjustment when seasonality is present.     

一类非线性Sturm—Louville问题的周期解

讨论了一类非线性Ｓｔｕｒｍ－Ｌｏｗｉｌｌｅ问题的周期解的分布情况，给出了周期解存在的一个充分必要条件。