A note on export openness and regional wage disparity in Central and Eastern Europe

This paper extends the empirical literature on the effects of trade liberalization on regional disparities within a country. Studying the case of the Central and Eastern European countries, we find significant convergence of real wages in Poland and Bulgaria, only. Furthermore, countries with a faster growing export openness in the period 1991–1998 experienced larger increases in their regional disparities. Especially, intermediate goods trade seems to have been a main driving force. Our estimates suggest that the long run impact of rising intermediate goods export openness in the last decade was a 23% increase in the average economys variance of real wages.Received: December 2002/Accepted: January 2004The authors are grateful to two anonymous referees for their helpful suggestions.     

Migration analysis using data with time intervals of differing widths

Migration data collected for periods of differing lengths will yield inconsistent population forecasts, inconsistent multiregional life tables, and alternative interpretations of mobility levels and migration patterns. In this paper, examples are first given to illustrate the effects of migration interval choice on demographic variables. The moverstayer model and its generalizations are discussed in their role as models useful in achieving consistency. It is argued that in addition to theievel of mobility, the geographic pattern of migration flows is also affected by the choice of interval width.     

Endogenising demand for information in road transport

In this paper, the impact of endogenous information provision to drivers in road transport is investigated. A static economic equilibrium model is used, which allows potential road users to buy information on the prevailing (stochastic) traffic situation. It takes for granted that an individual will try to acquire proper information when the private benefits of doing so exceed the private costs. By using an information model for road users, the interesting result is found that the provision of endogenous information leads to a strict Pareto improvement. Furthermore, the model shows that — depending on the price of information — it can be efficiency improving to subsidise or tax the motorist information to the user. Finally, there is a relationship between fine congestion pricing and subsidising motorist information. It turns out that the social welfare maximising subsidy under first-best congestion pricing is equal to zero. However, subsidising information may be an attractive policy instrument when a flat congestion pricing scheme is preferred.Participates in the VSB-fonds sponsored research project Transport and Environment     

Formation of alkylated aromatic acids in groundwater by anaerobic degradation of alkylbenzenes

Evidence for the presence of previously unreported alkylated aromatic acids in anaerobic groundwater samples from a jet fuel-contaminated site is presented. The redox conditions are dominated by sulfate reduction. A gas chromatography/mass spectrometry screening showed a composition of aromatic hydrocarbons ranging from BTEX (C(0)-C(2)-substituted benzenes) up to C(7)-benzenes. Known metabolites like methylbenzoates (C(1)-BA), C(2)-BA, C(3)-BA as well as methylbenzylsuccinates (C(1)-BSA) were detected. Additionally, previously unreported metabolites of higher alkylated benzenes have been identified in the extracts: those are C(2)-BSA to C(5)-BSA as well as C(4)-BA to C(6)-BA, which were detected in the microg/l-concentration range. The formation of C(1)- and C(2)-BSA as well as the C(1)- and C(2)-BA can be linked to structurally corresponding parent contaminants like the xylene isomers and the trimethylbenzene isomers. The C(3)-BSA and C(3)-BA represent metabolites of C(4)-benzenes. The occurrence of C(4)-C(5)-BSA and C(4)-C(6)-BA is attributed to C(5)-C(7)-benzenes acting as parent compounds. The concentration of total aromatic contaminants decreased along the plume centre line. In contrast, benzoates and benzylsuccinates (BA and BSA) showed constant concentrations over a distance of 84 m. BA concentrations were up to 162 times higher compared to BSA, as indicated by the ratio f(BA/BSA). A pronounced transient behaviour of BSA or an overall persistent behaviour of BA can explain this. Hence, along the plume centre line, f(BA/BSA) was constant over a distance of 128 m. The degradation products detected in a monitoring well are not necessarily tied to contaminants detected in that well. Therefore, the metabolite plume is partly located in front of the contaminant plume, but does not significantly migrate downstream the plume toe.     

半导体PVD工艺用溅射靶材诞生的故事--余姚"造靶"札记

1 前言 超大规模集成电路制造用的溅射靶材是采用超高纯度金属经特殊加工工艺生产出来的,是最终形成生产半导体必需的配线材料,半导体集成度性能的提升非常依赖于靶材技术的进步;之前,只有美国、日本等少数跨国公司具备大规模制造溅射靶材的能力,目前中国半导体工业用靶材全部依赖进口.然而在2006年1月,却传来一条震憾性的新闻,我国第一条超大规模集成电路制造用溅射靶材生产线在宁波余姚实现了批量产.据了解,这个创造历史的企业是由江丰集团宁波长城精工实业有限公司(简称长城精工)投资的,此项目的诞生与三个海归博士的回国创业也紧密的联系在一起.     

Finite element analysis of optimized brace angle for the diagrid structural system

International Journal of Steel Structures - The Diagrid structural system is considered to be the best structural system for constructing free form structures, but it is also a very effective...     

《通过对改造前后建筑物数据进行聚类分析确定影响办公建筑能源消耗的关键变量》

本研究旨在确定影响空调办公建筑能耗的关键建筑设计变量。本研究基于热带气候条件下的新加坡进行。结合56个办公楼改造前后能源审计报告数据进行评估分析。从这些报告中提取的14个建筑变量的列表构成了超集。对这些数据进行系统分析,得出影响能耗和改造决策的关键变量。为此,利用k均值聚类确定了一个稳健的迭代过程。该过程对14个变量的所有组合进行了测试,以应对改造前后条件下的能源使用强度(EUI,kW·h/m~2·a)的变化。结果表明,最佳变量包括:1)总建筑面积(GFA);2)非空调能耗;3)冷却装置的平均效率;4)冷却装置的装机容量。这些信息可以用来探索需要改造的办公楼的节能潜力。由此产生的集群还可以用来根据改造前的条件和节能潜力来对建筑物进行基准测试。