风力发电技术经济分析及对策

介绍了中、美等6个国家的电力构成以及世界风能资源的分布,并对世界风能资源经济效益进行了分析,阐述了风力发电的前景,指出了我国风电产业存在的问题,并提出发展我国风电产业的建议:研发大型风电机组,强化环保法规及给予风电产业以优惠政策.     

弯曲液面的附加压强

本文主要从球形液面内、外的压强差和任意弯曲液面内、外的压强差两个方面推导 了弯曲液面的附加压强公式。     

左思风力之成因初探

西晋诗人左思的诗风在西晋文坛上独树一帜，称之为“左思风力”，前人对此有较多地论述，然而就诗风形成的原因却缺乏深入地探究。本文试图从社会时代背景、家庭因素、性格特征三个方面对此加以分析，旨在能够更好地把握左思其人及其诗风。     

Interpreting DNA Mixtures with Related Contributors in Subdivided Populations

Abstract.  In this paper, we study the statistical interpretation of forensic DNA mixtures with related contributors in subdivided populations. Compact general formulae for match probabilities are obtained for two situations: a relative of one tested person is an unknown contributor of a DNA mixture; and two related unknowns are contributors. The effect of kinship and population structure is illustrated using a real case example.     

Household debt and financial assets: evidence from Germany, Great Britain and the USA

Summary.  We explore the determinants of debt, financial assets and net worth at the household level by using survey data for Germany, Great Britain and the USA. To identify which households are potentially vulnerable to adverse changes in the economic environment, we also explore the determinants of a range of measures of financial pressure: the probability that a household has negative net worth; the debt-to-income ratio; mortgage income gearing; the saving-to-income ratio. Our empirical findings suggest that the poorest and the youngest households are the most vulnerable to adverse changes in their financial circumstances.     

基于主成分分析的我国西部地区间产业结构转换能力评价

产业结构的演进和转换是经济发展的本质特征,也是促进经济持续稳定协调发展的关键。西部地区产业结构转换能力的地区差异十分明显,本文阐述了影响地区产业结构转换的一般因素,并通过主成分分析方法对影响西部地区产业结构转换的主要因素进行了分析,并对西部各地区产业结构转换能力、转换速度以及转换方向进行了分析评价。     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

一类二阶变系数微分方程的解

通过变量变换 ,将变系数线性常微分方程化为常系数线性常微分方程 ,再利用常数变易法给出了一类二阶变系数非齐线性微分方程的通解。     

我国中小企业面临的压力与对策

随着经济全球化的进一步发展,中国市场与国际市场逐渐融为一体,我国的中小企业将遇到更加激烈的竞争。我们必须抓住机遇,利用当前出现的国内外有利条件,制订应对挑战的策略,使中小企业在新环境里不断发展。     

高压微波催化合成肉桂酸甲酯

在硫酸铁铵的催化下 ,利用高压微波技术 ,快速合成了肉桂酸甲酯。最佳反应条件为 :甲醇和肉桂酸的摩尔比为 5 :1,催化剂用量为 2 .0g ,微波时间为 3min ,微波功率为 72 9W ,产率达93.8%。