安徽应对刘易斯拐点的对策建议

劳动力供应由过剩向短缺转变、工资开始上涨的时点即＂刘易斯拐点＂。由于中国经济的持续发展,以及计划生育政策效应,青壮年劳动力供给已开始出现供不应求现象,工资普遍上涨,中国＂刘易斯拐点＂已经悄然到来。＂刘易斯拐点＂对于经济、社会发展、转型具有标志性意义,安徽是传统农业、劳动力大省,应抓住机遇,顺势而为,积极应对。     

铸造起重机应力仿真与疲劳寿命评估

采用有限元分析法与现场测试相结合的方法来得到主梁的应力情况。从而得出在外主梁下盖板跨中位置的主应力与外主梁主腹板两端剪应力最大,这几处附近的焊缝部位存在着应力集中现象,需结合现场采集的数据对这几处做疲劳寿命评估。结果得出虽然跨中焊缝处应力最大,但其寿命仍有46年,此铸造起重机仍然安全。     

Using Empirical Point Elasticities to Teach Tax Incidence

Using point elasticities rather than using either arc elasticities or slopes of demand and supply curves provides the best method for teaching students about the economic impacts of excise taxes. Not only does a point-elasticity approach simplify theoretical analysis of tax impacts, but it also allows instructors to take advantage of publicly available empirical estimates of demand and supply elasticities to show students how theoretical results can be applied to real-world tax policy issues. To illustrate these advantages, the authors use several available estimates of point elasticities of demand and supply of raw sugar to calculate the economic impacts of a recently proposed penny-per-pound tax on raw cane sugar grown in the Florida Everglades.     

Time Changes for Lévy Processes

The goal of this paper is to consider pure jump Lévy processes of finite variation with an infinite arrival rate of jumps as models for the logarithm of asset prices. These processes may be written as time-changed Brownian motion. We exhibit the explicit time change for each of a wide class of Lévy processes and show that the time change is a weighted price move measure of time. Additionally, we present a number of Lévy processes that are analytically tractable, in their characteristic functions and Lévy densities, and hence are relevant for option pricing.     

原油降凝剂的研究进展

本文概述了原油降凝剂的发展概况、作用原理和近年来的发展趋势以及今后应重点解决的问题。     

激光点焊技术在通风槽板制造中的应用

本文主要介绍激光点焊技术在大型电机通风槽板加工过程中的应用,分析了激光点焊中主要加工参数对焊接质量的影响。并对现有通风槽板的几种加工工艺方法进行分析和比较。     

小车河铁路隧道边坡的加固方案分析

边坡稳定是一个非常复杂的问题,文章采用有限元分析法(运用有限元软件ANSYS),通过对毗邻小车河铁路隧道的房产开发项目的基坑开挖过程进行数值模拟分析,从理论上得出了该工程对既有铁路隧道影响程度,同时提出相应的加固处理建议。     

Putting the learning curve in context

In implementation of change, people learn new ways of doing things, develop new skills, and adopt new organizational routines. This paper applies learning curve theory to implementation by developing a system dynamics model that includes two extensions to classic learning curve theory. First, the model includes a required output level for the individual. Second, the model includes a budget constraint on time that forces a choice between an old and a new way to achieve the output. Doing work the new way builds experience, increasing productivity and thus favoring continued use of the new skill, but model analysis demonstrates that this reinforcing process works to favor the new skill only at relatively high levels of productivity. Otherwise, the same process is a vicious cycle, driving out the new skill. The model exhibits a mode of behavior in which learning begins and then stalls and another mode in which the new skill becomes the preferred one. The paper identifies the tipping point between these two modes and characterizes the transition problem: Learning by doing is a dynamic process, a transition from use of an old way to a new way that requires accumulating experience beyond a threshold.     

Forecasting the business cycle using survey data

Regular business survey data are published as percentages of firms predicting higher, equal or lower values of some reference variable. Time series of such percentages do not fit production data too well. Univariate models often produce forecasts which are just as accurarate. Still, surveys contain anticipative judgement which, when combined with univariate modeling and proper filtering, may produce a good indicator for business cycle turning points. The way survey data are transformed so as to fit statistics on production seems not to be of much importance. A case study of the Finnish forest industry is offered as an example.     

我国房地产业发展周期与拐点探析

我国房地产发展周期已到繁荣阶段的中后期，虽然不少地方的房价还在涨，但有的地方房价已开始大涨后的下降，这预示房地产发展周期的拐点即将出现，应引起政府决策层的高度重视，以未雨绸缪。