变形系统的混沌化研究

变形体变形系统是一个动态的非线性复合系统.变形运动的混沌行为验证主要通过计算系统的Lyapunov指数的正负得出.本文通过对变形系统的动力方程的混沌化研究,验证了当系统为单一连续时间系统时,构造合适的状态矩阵,保证其特征值大于某一参数就能确保变形系统的混沌化,而如果系统是反馈系统,合理选择反馈参数一样能使系统走向混沌.     

海量矿业权核查成果数据存储与访问的优化技术研究

针对矿业权核查单矿权成果数据具有文件小、数量多、异构、多源等特点,为了有效地存储这些数据到Oracle数据库中,实现快速提取及显示,并能够将一个矿业权的提取时长控制在1秒以内,本文给出了从建立数据库实体到查询、显示过程所涉及诸多问题的一个完整的优化方案。首先建立了一个完整的、科学的数据存储模型,并采用范围-列表分区模式对大型表进行分区,同时采用通过调整Oracle系统高速缓冲区、减少表连接、优化SQL查询语句、在客户端分页显示查询结果等优化方案,有效提升表中数据的查询速度,以达到优化目的。     

变形测量异常数据处理中小波变换最佳级数的确定

综合分析数据去噪效果的4个分项评价指标,即数据的均方根差变化量、互相关系数、信噪比及平滑度,将各分项评价指标归化到0,1后相加得到总体评价指标,将总体评价指标最大值所对应的级数定义为小波分解与重构的最佳级数。模拟和实测两个算例验证了此方法的有效性。     

Spatial Distribution and Temporal Variation of the Winter Wheat Late Frost Disaster in Henan, China

The winter wheat late frost disaster(WFD) occurs mainly in the Yellow and Huaihe River area,of which Henan Province covers the most part.Henan is the major area of wheat production in China,but it is severely hit by the WFD.In this study,we construct a WFD index based on the minimum temperature and the winter wheat development period(WDP).The WFD degrees and days at 30 agrometeorological stations in Henan Province during the period of 1981-2004 are calculated.For the large-scale temporal variation analysis of WFD,the 24-yr WDP observation series is relatively short,so it is expanded by using the relation between the turning green date of winter wheat and the 5-day running mean temperature and that between the stem elongation phase and the effective cumulative temperature above a critical value of 2.5 ℃.The WFD data are also expanded for the last 50 years and are analyzed by using the empirical orthogonal function(EOF) and the Morlet wavelet methods.Characteristics in the spatial distribution and temporal variation of WFD are revealed.The results show that the frequency of WFD is generally high,exceeding 40% in parts of Henan,and exhibits a rising trend in the period of 1970-1990.The variation trend of WFD degrees is similar to that of WFD days,and the areas with higher WFD degrees coincide the areas with more WFD days.Moreover,the WFD degree has a greater impact on the winter wheat yield than the WFD days.The areas with high WFD degrees lie in the southeast and southwest of Henan,and the areas with low WFD degrees lie in the south of the Huaihe River and parts of western Henan.Temporal variations of the first and second EOF modes of the WFD degree display 16-and quasi-22-yr periodicities,respectively.The areas of high(low) WFD frequency are distributed in the northern Henan and the southwest border of Henan(the northeast Henan and the middle part of southwest Henan).The temporal variation of the first(second) EOF mode of WFD days exhibits a periodicity(periodicities) of quasi-4 yr(quasi-3 and quasi-6-7 yr).     

Effects of Crop Growth and Development on Land Surface Fluxes

In this study, the Crop Estimation through Resource and Environment Synthesis model (CERES3.0) was coupled into the Biosphere-Atmosphere Transfer Scheme (BATS), which is called BATS CERES, to represent interactions between the land surface and crop growth processes. The effects of crop growth and development on land surface processes were then studied based on numerical simulations using the land surface models. Six sensitivity experiments by BATS show that the land surface fluxes underwent substantial changes when the leaf area index was changed from 0 to 6 m2 m-2. Numerical experiments for Yucheng and Taoyuan stations reveal that the coupled model could capture not only the responses of crop growth and development to environmental conditions, but also the feedbacks to land surface processes. For quantitative evaluation of the effects of crop growth and development on surface fluxes in China, two numerical experiments were conducted over continental China: one by BATS CERES and one by the original BATS. Comparison of the two runs shows decreases of leaf area index and fractional vegetation cover when incorporating dynamic crops in land surface simulation, which lead to less canopy interception, vegetation transpiration, total evapotranspiration, top soil moisture, and more soil evaporation, surface runoff, and root zone soil moisture. These changes are accompanied by decreasing latent heat flux and increasing sensible heat flux in the cropland region. In addition, the comparison between the simulations and observations proved that incorporating the crop growth and development process into the land surface model could reduce the systematic biases of the simulated leaf area index and top soil moisture, hence improve the simulation of land surface fluxes.     

综合气象观测系统业务运行综合评估技术研究

综合气象观测网运行监控系统是我国气象探测设备运行保障的实时业务系统.文章以装备技术保障工程理论为基础,按可靠性、维修性、保障性、业务性、经济性等多个范畴,从装备运行状态、装备性能参数、探测数据质量、通信传输、供应保障、维护维修等方面,提出了针对我国综合气象观测网中各类设备的运行、维护和保障等工作进行综合评估的技术方法,...     

三种干旱指数在山西省干旱分析中的比较

利用1957-2003年山西省30个测站逐月、逐年降水量、平均气温资料、降水距平百分率、帕尔默指数和Z指数等三种干旱指数的计算方法和判定标准,分别在山西省北部、中部、南部和全省的旱涝状况进行判定的基础上,对三种干旱指数的判定结果进行了比较和相关分析。结果表明：（1）从旱涝年发生频次来看,降水距平百分率判别干旱的趋势可信...     

Polychaete/amphipod ratio as an indicator of environmental impact related to offshore oil and gas production along the Norwegian continental shelf

Benthic faunal data is regularly collected worldwide to assess the ecological quality of marine environments. Recently, there has been renewed interest in developing biological indices able to identify environmental status and potential anthropogenic impacts. In this paper we evaluate the performance of a general polychaete/amphipod ratio along the Norwegian continental shelf as an environmental indicator for offshore oil and gas impacts. Two main trends are apparent: first, a contamination gradient is discernible from where production takes place compared to stations 10,000 m away. Second, the quality of the marine environment has improved over time. These results are consistent with monitoring reports employing a combination of uni- and multi-variate statistics. Thus, we consider this ratio as a relatively simple, useful and potentially cost-effective complement to other more demanding assessment techniques. Because of its strong theoretical basis, it may also be useful for detecting ecological change as a result of other activities.     

Assessment of Heavy Metal Contamination of Wetland Soils from a Typical Aquatic–Terrestrial Ecotone in Haihe River Basin,North China

Surface soils were collected in the aquatic–terrestrial ecotone (ATE) of Yongnianwa wetland, downstream of Haihe River basin of North China in June of 2007. Samples were subjected to a total digestion technique before they were analyzed for total concentrations of Cr, Cu, Ni, Pb, and Zn to investigate their pollution levels in the ATE. The contamination index, integrated contamination index, geoaccumulation index, toxic units, and sum of toxic units were adopted to assess the heavy metal contamination levels and ecotoxicity, respectively. The results showed all the selected element concentrations in upland soils of the ecotone were relatively higher than those in the lowland soils. No Cr pollution was observed in all soil samples, but almost all samples were slightly polluted by Cu, Ni, Pb, and Zn except for Site 1. The contamination indexes and geoaccumulation indexes consistently presented no contamination for Site 1 and slight contamination for other sites. The ΣTUs increased from lowland to upland, but the whole level of toxicity in this ecotone was relatively low.     

Assessment of Metal Pollution in Water and Surface Sediments of the Seyhan River,Turkey, Using Different Indexes

The aim of this study was to assess the level of heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contamination and enrichment in the surface sediments of the Seyhan River, which is the receiving water body of both treated and untreated municipal and industrial effluents as well as agricultural drainage waters generated within Adana, Turkey. Sediment and water samples were taken from six previously determined stations covering the downstream of the Seyhan dam during both wet and dry seasons and the samples were then analyzed for the heavy metals of concern. When both dry and wet seasons were considered, metal concentrations varied significantly within a broad range with Al, 7210–33 967 mg kg^?1 dw; Cr, 46–122 mg kg^?1 dw; Cu, 6–57 mg kg^?1 dw; Fe, 10 294–26 556 mg kg^?1 dw; Mn, 144–638 mg kg^?1 dw; Ni, 82–215 mg kg^?1 dw; Pb, 11–75 mg kg^?1 dw; Zn, 34–146 mg kg^?1 dw in the sediments while Cd was at non‐detectable levels for all stations. For both seasons combined, the enrichment factor (EF) and the geo‐accumulation index (I_geo) for the sediments in terms of the specified metals ranged from 0.56 to 10.36 and ?2.92 to 1.56, respectively, throughout the lower Seyhan River. The sediment quality guidelines (SQG) of US‐EPA suggested the sediments of the Seyhan River demonstrated “unpolluted to moderate pollution” of Cu, Pb, and Zn, “moderate to very strong pollution” of Cr and Ni. The water quality data, on the other hand, indicated very low levels of these metals suggesting that the metal content in the surface sediments were most probably originating from fine sediments transported along the river route instead of water/wastewater discharges with high metal content.