SARS疫情应急管理系统研究

研究了具有分区预警减灾功能的SARS疫情应急管理系统的结构、模型与开发问题,这个系统被确定具有分区疫情预警、区域减灾对策评估功能.文章首先分析了系统的功能需求和结构体系,进一步讨论了系统的决策分析模型,最后讨论了基于GIS技术建立SARS疫情应急管理系统的技术问题.     

基于柔度指标的系杆拱桥损伤识别与寿命预测

提出了一种柔度曲率差变化率的损伤识别指标,通过试验验证指标的有效性,并应用于系杆拱桥算例损伤识别,进而预测其构件剩余寿命。利用系杆拱桥算例中吊杆、拱肋与横撑的多种损伤工况验证了新指标的有效性与抗噪性,基于所提损伤指标建立损伤评估函数并构造相应曲线,用于精确定量评估损伤程度,并采用损伤评估函数预测构件剩余寿命。结果表明,柔度曲率差变化率可有效用于系杆拱桥损伤评估且噪声鲁棒性好,运用结构不同阶段的有损模态信息构建损伤评估函数的方法可行、合理,所提寿命预测方法考虑了损伤非线性累积,意义明确。建议在使用该方法诊断下承式拱桥吊杆时,宜采用拱肋振型向量构建损伤指标,实桥试验时应将振型传感器置于拱肋处。     

Genetic and DNA-methylation changes induced by potassium dichromate in Brassica napus L

This study evaluated genetic and DNA methylation alteration induced by potassium dichromate in Brassica napus L. plants. Amplified fragment length polymorphism (AFLP) and selective amplification of polymorphic loci (SAMPL) tests revealed dose-related increases in sequence alterations in plantlets exposed to 10-200 mg/l potassium dichromate. Individual plantlets exposed to chromium under similar conditions showed different AFLP and SAMPL DNA profiles. These observations suggest random DNA mutation in response to potassium dichromate and argue against preferential sites for mutation. DNA methylation changes in response to chromium treatment were also evaluated. Two complementary approaches were applied: (i) immunolabelling, using a monoclonal antibody against 5-methylcytosine; and (ii) methylation-sensitive amplified polymorphism (MSAP). Immunolabelling showed cytosine-hypermethylation in the Brassica napus L. genome when plants were treated with potassium dichromate. MSAP analysis showed extensive methylation changes in CCGG-sequences, with the net result being genome-wide hypermethylation. These results showed a clear DNA alteration in plants as a response to chromium exposure and the effect was dose-dependent. DNA polymorphism detected by different markers supports the effectiveness of the use of these tools for the investigation of environmental toxicology and for evaluating the concentration of pollutants by DNA analysis in plants.     

Enhancement of photocatalytic activity of sprayed nitrogen-containing ZnO powders by coupling with metal oxides during the acetaldehyde decomposition

Colored N-containing MOx-ZnO (M = W, V) composite powders with high surface area were synthesized by spray pyrolysis. The nitrogen content was controlled from 600 to 3000 ppm by changing the powder ingredients and the spray pyrolysis temperature. Ultraviolet-visible spectra indicated that the N-containing MOx-ZnO powders absorbed not only ultraviolet light like pure ZnO powder, but also some visible-light. Acetaldehyde decomposition was used as a probe reaction to evaluate the photocatalysis of these MOx-ZnO powders. The photocatalytic activity of the N-containing ZnO powder was pronouncedly enhanced by the WO3 or V2O5 addition under both UV and visible-light irradiation. This enhancement was ascribed to the MOx acting as a sink for photogenerated electrons in the UV case, and to a synergistic effect of N-doping and MOx-ZnO coupling in the case of visible-light.     

重庆市春季大气NO2浓度空间分布特征研究

为了解重庆市大气中NO2浓度空间分布特征，研究了一种被动式采样器在该地区野外采集大气NO2的可行性，并在2004年3～5月期间利用这种采样器对重庆城区2600Km^2范围大气中的NO2进行了连续观测。结果表明：NO2浓度值随城区类型、观测点位置不同有一定的差异，其分布与交通强度密切相关；前后两次观测有相同(除南岸区外)的区间浓度梯度。     

Risk curve boundaries

Insights into the science and the dynamics associated with the stimulus-injury relationship of the human system are often gained by focusing on the results obtained from human surrogate testing. These results are commonly mapped into an injury risk paradigm for the purpose of characterizing the stimulus injury response: the injury risk curve. However, the quality and quantity of the data along with the experimental design are critical factors when considering the value of the estimated risk curve. Presented in this article is an analysis of injury risk curves in terms of their usability and appropriateness with respect to the sample size, stimulus distribution over the critical range, censoring, shape of the underlying risk function, and the inclusion of "actual" (uncensored) along with censored data. The results from this analysis indicate that for "large" biomechanical injury data sets there is no advantage to using actual data; censored data will yield the same injury risk curve as actual data. However, for "small" biomechanical injury data sets the inclusion of actual data will significantly improve the quality of the resulting risk curve. In addition, the results show that the amount of injury data needed to generate a risk curve with a given confidence bound is not only dependent on the relative contribution of the censored data and actual data but also on the shape of the risk function along with the stimulus distribution over the critical range. Confidence intervals are presented for the thoracic injury risk and the head injury risk to show the influence of data distribution on the goodness of the risk function estimation.     

油库火灾危害分析

运用“池火灾伤害模型”,对某油库汽油罐火灾危害程度进行分析,得出火灾危害程度与事故原点距离之间的关系,为油库安全运营提供参考。     

Analysis of 3-D Urban Databases with Respect to Pollution Dispersion for a Number of European and American Cities

Dispersion models require as input various geometrical parameters to calculate the flow field and dispersion characteristics in the urban environment. As a result of recent advances in digital photogrammetry and remote sensing, databases of the actual 3-D geometry of city centre areas are now increasingly available. In this work we outline a procedure to reduce this large amount of data to a structured input for urban pollution dispersion models, i.e. to extract the important flow and dispersion parameters from the urban databases. Based on a review of the scientific literature, we have identified a number of parameters relevant to the modelling of pollution dispersion and atmospheric flows in urban areas. These parameters are: the plan and frontal area densities, the plan and frontal area density as a function of height, the distribution of heights, their standard deviation, the aerodynamic roughness length and the sky view factor.These parameters are obtained by analysing urban Digital Elevation Models (DEMs) which are regularly spaced grids of elevation values. Examples of the parameters calculated from high-resolution databases (with pixel size of about 1 m) for three European (London, Toulouse and Berlin) and two North American (Salt Lake City and Los Angeles) cities are presented and discussed. The calculated aerodynamic roughness length was smaller for the European cities than for the North American ones. A multiplicative correction factor to the aerodynamic roughness length is proposed to include the effect of the variability of the building heights.     

Radiosensitivity of subterranean bacteria in the Hungarian Upper Permian Siltstone Formation

The main purpose of this work was to study the radioresistance of subterranean aerobic and anaerobic isolates from the Hungarian Upper Permian Siltstone (Aleurolite) Formation, in order to assess the safety of potential sites of future underground repositories for nuclear waste. A total of 93 isolates were studied. The radiosensitivities of these aerobic and anaerobic bacteria isolates were determined: the D10 values (decimal reducing doses) of the aerobic spore-formers lay in the range 0.80 -2.44 kGy, and those of the anaerobic spore-formers lay in the range 1.86 4.93 kGy. The D10 values of the aerobic and anaerobic vegetative isolates were much lower, in the ranges 0.11 0.57 and 0.22-0.40 kGy. respectively. The variability in bacterial radioresistance indicates the biodiversity at this potential disposal site. These results can affect the construction of a future underground repository, since knowledge of the most resistant microorganism may be of importance as concerns calculation of the time required to inactivate the bacteria surrounding the containers.