一种新的海面空气动力学粗糙度方案

综合利用6个国际海洋观测试验资料,共同验证Charnock参数与无因次粗糙度长度(z0/Hs)对波龄的依赖性,建立粗糙度回归模型,并对其进行显著性和适用性检验,从而导出粗糙度无因子形式与有效波高有关.利用研制的粗糙度方案(SP07)研究充分发展风浪与风区、风时和水深的关系,及粗糙度长度对摩擦速度和波龄的敏感度.把SP07方案引人国际上最先进的计算海气通量的COARE(V3.0)算法中,选择1985年12月在北海的FPN平台上的试验资料,进一步检验SP07方案的适用性.得出目前国际上最先进的002和TY01方案较高估计了摩擦速度,YT96方案略偏低估计了摩擦速度,文中研制的方案计算结果与实测结果最接近.     

新疆干旱地区褐家鼠种群结构特征的初步研究

根据多年的实地调查数据，研究了褐家鼠在新疆干旱环境中的种群生态学特征。结果表明，褐家鼠种群内禀增长率(rm)0.221，种群周限增长率(λ)为1．247。同时还发现，褐家鼠移入新疆干旱环境后，其种群年凝结构尚未见明显变化，仍为稳定增长。     

空间网架结构在地震作用下的损伤累积分析

本文从连续介质损伤力学的基础理论出发，提出了弹性模量等价性假设，并在这一假设的基础上建立了考虑损伤累积效应的空间网架结构分析的有限元列式。最后，以空间网架结构在地震作用下的损伤累积分析为例，给出了本文方法的具体实施步骤。     

On the stability of extremely diluted aqueous solutions at high ionic strength

An extensive study has been carried out on extremely diluted aqueous solutions (EDS). These solutions revealed a really intriguing physico-chemical behaviour, characterized by multiple independent variables. Because of their behaviour, EDS can be described as far-from-equilibrium systems, capable of self-organization as a consequence of little perturbations. In this paper we investigate the stability of the calorimetric behaviour of EDS with a high ionic force, due to the presence of the sodium chloride electrolyte. We measured the excess heats of mixing of EDS with basic solutions, both with and without a high concentration of NaCl, and compared the results. In particular, we explored these concentrations: 0.5 and 1Mmol kg⁻¹). The analysis of the experimental results shows that the calorimetric response of the EDS is stable when they are in a concentrated solution of NaCl. That is of great relevance for the eventual pharmacological action of these solutions, since it involves the interaction with fluids of complex chemical composition and high concentration.     

宇宙年龄问题上的疑难

宇宙年龄是大爆炸宇宙学中的一个关键性的问题．文章对这问题的缘由、历史以及现状作了阐明．重点讨论了哈勃常数的实测值大小在宇宙年龄问题中的核心作用     

基于小波变换的二维红外相关光谱鉴别人参的生长年限

探讨了将小波变换处理方法应用到不同生长年限人参的二维红外相关光谱数据预处理中。结果表明： 经过小波变换处理后,可以有效提高二维红外相关光谱同步图的分辨率,增强谱图中的信号峰,提高谱图中重叠峰的分离度,还可提供新的信息,从而在很大程度上增强了二维红外相关光谱对复杂体系的分析鉴别能力。借助此方法,可以鉴别人参的生长年限。     

A numerical scheme to the McKendrick–von Foerster equation with diffusion in age

In this paper a numerical scheme for McKendrick–von Foerster equation with diffusion in age (MV‐D) is proposed. First, we discretize the time variable to get a second‐order ordinary differential equation (ODE). At each time level, well‐posedness of this ODE is established using classical methods. Stability estimates for this semidiscrete scheme are derived. Later we construct piecewise linear (in time) functions using the solutions of the semidiscrete problems to approximate the solution to MV‐D and establish the convergence result. Numerical results are presented in some cases and compared with the corresponding analytic solutions where the latter is known explicitly.     

A common age effect model for the mortality of multiple populations

We introduce a model for the mortality rates of multiple populations. To build the proposed model we investigate to what extent a common age effect can be found among the mortality experiences of several countries and use a common principal component analysis to estimate a common age effect in an age–period model for multiple populations. The fit of the proposed model is then compared to age–period models fitted to each country individually, and to the fit of the model proposed by Li and Lee (2005).Although we do not consider stochastic mortality projections in this paper, we argue that the proposed common age effect model can be extended to a stochastic mortality model for multiple populations, which allows to generate mortality scenarios simultaneously for all considered populations. This is particularly relevant when mortality derivatives are used to hedge the longevity risk in an annuity portfolio as this often means that the underlying population for the derivatives is not the same as the population in the annuity portfolio.     

Asymptotic speed of propagation of wave fronts in a lattice delay differential equation with global interaction

In this paper, we derive a lattice model for a single speciesin a one-dimensional patchy environment with infinite numberof patches connected locally by diffusion. Under the assumptionthat the death and diffusion rates of the mature populationare age independent, we show that the dynamics of the maturepopulation is governed by a lattice delay differential equationwith global interactions. We study the well-posedness of theinitial-value problem and obtain the existence of monotone travellingwaves for wave speeds c > c_*. We show that the minimal wavespeed c_* is also the asymptotic speed of propagation, whichdepends on the maturation period and the diffusion rate of maturepopulation monotonically.