某大型复杂结构地震响应与控制研究

针对某大型复杂结构的地震响应及控制策略进行了研究.首先,建立该结构的整体有限元模型,采用Ritz向量法对结构进行模态分析,研究该复杂结构的振动特性,基于位能加权平均法求解了该复杂结构等效阻尼比;随后,研究了不同布置型式下粘滞消能支撑的受力特点和计算模型;最后,对该结构进行减振设计,分析了不同消能支撑布置形式下的减振效果...     

Safety Climate and Prediction of Ergonomic Behavior

One of the most important ways to prevent accidents is to consider safety climate or culture. Moreover, some studies suggest that behavior contributes to 86%-96% of all injuries. This cross-sectional study took place in an Iranian petrochemical company in 2010. Vinodkumar and Bhasi’s safety climate questionnaire and an ergonomic behavior sampling checklist were the data collection tools. Cronbach’s a for questionnaire reliability was .928. With reference to the results of a pilot study, a sample of 1755 was determined for behavior sampling. We used principal component analysis (PCA) to derive the coefficient of paths in the path model and the Anderson-Rabin method to calculate factor scores. The results showed that safety climate was an effective predictor of ergonomic behavior (p < .01). They also showed the importance of decreasing the number of workers with negative safety climate. Moreover, it is necessary to promote workers’ ergonomic behaviors in the workplace.     

Assessment of nitrogen leaching from arable land in large river basins: Part II: regionalisation using fuzzy rule based modelling

This study deals with fuzzy rule based modelling of nitrogen (N)-leaching from arable land. Main purpose is the elaboration of a method, which allows dynamical regionalisation of results from process-based models for large regions and can be efficiently included in metamodels or decision support systems for rapid integrated assessment of water resources. The paper is the second part of a two-part paper. In the first paper the distributed ecohydrological model SWIM had been applied to calculate and analyse nitrogen dynamics in arable soils for a set of representative natural and management conditions in the Saale River basin (Ecol. Model. (in press)). Here, in the second paper the results from those simulation experiments are used to define, train and validate fuzzy rule systems for the estimation of N-leaching. Nine fuzzy rule systems, specific for nine soil classes, were created from the simulation experiments, representing the conditions for the whole Saale River basin. The fuzzy rule systems operate on monthly time steps and consist of 15 rules and seven input variables each, which are compiled from time series of precipitation, percolation and evapotranspiration as well as from information about fertilizer and crop specific nitrogen uptake. Simulated annealing as a non-linear discrete optimisation method is used for automatic rule assessment. Validation of the fuzzy rule systems, carried out by split sampling of 30-year simulation period, shows satisfactory performance on an annual basis and good performance on the long-term basis with average correlation between SWIM-simulated and fuzzy rule-estimated N-leaching values of 0.78 and 0.94, respectively.     

Air Pollution Modelling at an Urban Scale – Russian Experience and Problems

Urban concentration fields are extremely inhomogeneous andtheir gradients are very high. It results in specificproblems when modelling air pollution at the urban scalethat are analysed in this paper. Some examples ofmisrepresentation of the urban concentration field,computed with the use of the source-receptor type models,are given here. They can help in understanding the natureof the problems we face and reveal deficiencies of thecomputational technologies in use. Filtering of thecomputed fields is suggested as an instrument for improvingtheir quality. Its efficiency is proved on the test runs.An algorithm for refinement of the filtered fields isintroduced in this paper.     

美国国家公园的管理对我国地质遗迹保护区管理体制建设的启示

我国地质自然保护区的建设始于1987年，与美国相比落后了100多年。自1987年我国开始建立第一批独立的地质自然保护区开始，到目前已建立地质自然保护区86处。地质遗迹资源管理体制正在建设之中，各项管理规章制度与运行机制有待进一步理顺。而经过100多年的发展，美国国家公园在管理方面有着十分科学务实的机构和完善的管理体系。本文在对美国国家公园管理机构和管理体系进行分析的基础上，对我国地质遗迹资源管理体制的建设提出建议。     

Integrated and comprehensive estimation of greenhouse gas emissions from land systems

Exchanges of carbon and nitrogen between the atmosphere and terrestrial ecosystems involve a complex set of interactions affected by both natural and management processes. Understanding these processes is important for managing ecosystem productivity and sustainability. Management processes also affect the net outcome of exchanges of greenhouse gases between terrestrial ecosystems and the atmosphere. In developing a national carbon accounting system (NCAS) for Australia to account for emissions and removal of greenhouse gases to and from the atmosphere, a carbon:nitrogen mass balance ecosystem model (FullCAM) was developed. The FullCAM model is a hybrid of empirical and process modelling. The approach enables application to a wide range of natural resource management issues, because it is at land-management-relevant spatial and temporal resolution and captures the main process and management drivers. The scenario-prediction capability can be used to determine the emissions consequences of different management activities. Because, in Australia, emissions of greenhouse gases are closely related to the retention of dead organic matter and the availability of nitrogen for plant growth, the carbon and nitrogen cycling as modelled are good indicators of ecosystem productivity and condition. The NCAS also emphasizes the advantages of a comprehensive and integrated approach to developing a continental scale ecosystem-modelling system that has relevance both to estimation of greenhouse gas emissions and sustainable management of natural resources.     

基于解释结构模型的应急机制系统分析

运用系统工程理论，对构成突发事件应急机制系统的8个要素进行了定性和定量化处理，建立了应急机制系统的多层递阶解释结构模型。通过模型，证明了要素被分为5个级别，分析了要素之间的纵向和横向关系，确定了信息机制和领导机制要素的基础重要性，为城市应急机制系统的分析、评价和建设提供科学依据。     

An increase in cost-effectiveness of first trimester maternal screening programmes for fetal chromosome anomalies is obtained by contingent testing

We assessed the discriminatory efficiency and cost-effectiveness of a novel way of organising first trimester screening for Down syndrome (DS), contingent testing, where a serological test (PAPP-A and β-hCG: the double test) is made in early first trimester and followed by nuchal translucency testing (NT) only in women with an intermediate risk, e.g. <1:65 and >1:1000, and not in all women as in normal first trimester screening (NFTS). Using Monte Carlo simulation contingent testing had a detection rate (DR) of 78.9% and a false-positive rate (FPR) of 4.0% for DS with 19.4% of women offered NT testing. The DR of NFTS was 85.5% and the FPR 4.4%. The decrease in NT screening was associated with an increase from 23% to 29% in the proportion of DS cases born. The cost of the contingent testing programme was £53 000 per DS case not born and £91 000 in NFTS. The number of aborted fetuses per DS case were 0.35 and 0.36, respectively. Thus, contingent testing is an organisation of first trimester screening where costs can be reduced with a marginal decrease in performance. Contingent testing is attractive in areas where NT screening is the bottleneck preventing the introduction of first trimester screening. Copyright © 2002 John Wiley & Sons, Ltd.     

Dynamics and Structural Changes of the Fluke Fauna in Fish of the Volga Delta Caused by the Rise of Water Level in the Caspian Sea

Changes in the Caspian Sea level and anthropogenic influences on biocenoses of the Volga Delta periodically result in the changes of dominant species among animal helminths. An abrupt rise of the sea level since the mid-1970s caused structural rearrangements in the fluke fauna of fish in the 1990s: the species whose development is connected with mollusks of the rheophilic complex became dominant.