北京市大气环境二氧化硫浓度分布初探

利用北京市大气自动监测系统冬季逐时二氧化硫浓度监测资料，分析研究了对数正态分布，Ｗｅｉｂｕｌｌ分布，指数分布等常用分布模型对监测资料人布推迟合的适用性，并估算出各种分布模型的参数值。研究发现城区及高百分位数二氧化硫浓度频率分布符合Ｗｅｉｂｕｌｌ分布，近郊及背景站的浓度分布符合常用的对数正态分布，二氧化硫浓度的频率分布不符合指数分布规律。     

空气质量指数(AQI)的社会经济影响因素分析——基于指数衰减效应视角

中国面临着严重的环境恶化问题,其中空气污染问题尤为突出.基于中国2014年全国城市空气质量数据,利用自然正交函数分析城市空气质量指数的时空演变特征,并采用基于衰减效应的矩阵指数空间设定模型探讨了空气污染的影响因素.研究结果表明:(1)AQI以京津冀为高值中心向周边地区呈衰减变化,污染核心区由京津冀逐渐向豫北地区和鲁西北地区扩散,年内AQI在1—9月呈现下降趋势,然后逐渐上升;(2)150个城市的空气质量指数呈现出明显的空间集聚;(3)矩阵指数空间设定模型优于空间滞后模型,并且城市间空气污染呈现出显著的空间衰减效应;(4)人均地区生产总值的提高、SO_2排放量和PM_(2.5)浓度增加是导致空气污染加剧的重要原因,而外商直接投资和环保意识的提高有助于改善中国的空气质量.     

基于指数平滑技术的装备维修备件需求预测

以装备维修备件的需求量预测问题为研究对象,运用指数平滑预测技术,构建了装备维修备件需求量预测模型,并借助Excel环境对某装备维修备件的需求量进行了预测。预测结果表明,该方法为科学预测装备维修备件的需求量提供了一种可行的方法。     

基于应力-强度干涉理论的可靠度点估计研究

研究了基于应力-强度干涉理论(SSI)的可靠度点估计的一般模型,进而给出了应力和强度均服从单参数指数分布和双参数指数分布时可靠度估计值计算公式,给出其与样本值之间的定量关系。对于应力和强度服从其他分布的情况,采用分布类型变换将其变换为指数分布,然后利用指数分布类型的研究结果给出可靠度估计值计算式,简化了计算。     

Predicting the variation in detection function in line transect sampling through random parameter model

A method for calibrating (localizing) detection function models in line transect sampling is proposed. The method is based on a random parameter model which supplies localized predictions of detection function parameters utilizing a few sample data points from the concerned location(s). The method has the clear advantage of being able to provide density estimates based on very few observations from a location which would be impossible through traditional methods. The method is successfully illustrated using census data on sambar (Cervus unicolor) from a set of wildlife sanctuaries in Kerala, India. The need for further research in this direction is indicated.     

OXYGEN SAG EQUATION FOR THREE-HALVES ORDER BOD REACTION1

Several published BOD data sets are examined to show that approximately half of them are described best in the least squares sense by treating the BOD equation as being of the three-halves order instead of first order. A dissolved oxygen (DO) sag equation for a stream is developed in which the BOD is described as a three-halves order reaction. The time when the minimum DO concentration occurs is calculated numerically. The DO sag model applied to example problems shows that an increase in the BOD reaction rate constant results in a smaller minimum DO concentration and a decrease in the time to reach the minimum DO.     

安全联锁设备SIL验证中的参数估计偏差分析*

为提高安全联锁系统（SIS）不可用度计算的准确性,减少SIL验证的不确定性偏差,研究参数估计置信度分别为70%和90%时功能安全标准IEC61508的恒定失效率算法与实际非恒定失效率（威布尔分布）算法结果的偏差。结果表明:在70%置信度时,采用指数分布算法计算PFDavg,比威布尔分布算法的计算结果偏大,2者的相对偏差平均值为68.01%;90%置信度时,2者的相对偏差平均值为42.63%,揭示功能安全标准IEC61508恒定失效率计算将显著高估SIS的不可用性,可能造成企业不必要的整改和相应的维护成本。     

叶绿素a对活性污泥中红斑顠体虫生长特性的影响

活性污泥-生物膜复合工艺在春夏之交常发生红斑顠体虫的爆发性繁殖,使系统性能恶化。用螺旋藻和活性污泥在光照培养箱中对红斑顠体虫进行培养,通过指数拟合,得出红斑顠体虫的指数增长率和倍增时间。用螺旋藻和活性污泥单独培养,红斑顠体虫倍增时间分别可达1.44 d和2.04 d。用活性污泥和螺旋藻对红斑顠体虫进行联合培养,发现在污泥浓度为132 mg/L时,叶绿素a浓度为85.9 mg/m3时,其倍增时间为1.14 d。可见在叶绿素a、活性污泥以及两者协同影响下,都可促进红斑顠体虫的生长。     

二次指数平滑法的成都市餐厨垃圾产量预测

餐厨垃圾的产生量直接影响其处理规模,指数平滑法是对于缺乏基础数据的模型预测的一种有效方法。本文以2001～2009年成都市餐厨垃圾产量数据为基础,运用二次指数平滑预测法对成都市餐厨垃圾产量进行预测,预测结果显示2010年成都市餐厨垃圾产量将达到514.96 t/d。     

Behavior of pyrimethanil,pyraclostrobin, boscalid,cypermethrin and chlorpyrifos residues on raspberry fruit and leaves of Laszka variety

The purpose of the research conducted was to investigate and evaluate the behavior of pyrimethanil, pyraclostrobin, boscalid, cypermethrin and chlorpyrifos, the active ingredients of selected fungicides and insecticides, on ripe fruit and in fully developed leaves of raspberry of the Laszka variety. The field trial was carried out in the period of one month starting from the first fruit picking. The results obtained indicated that residue levels on the day of the first crop picking did not even approximate the corresponding EU-MRLs (http://ec.europa.eu/sanco_pesticides). Individual substances in raspberry fruits and leaves disappeared at a similar rate. As a result of chlorpyrifos application to the soil, its residue in fruits and leaves occurred for the whole period of fruit bearing, though in fruit they dropped successively. To produce raspberries with residues below or equal to 0.01 μg g^?1, the application of pesticides should be stopped at least 2–3 weeks before the first crop picking, and on condition that an appropriate preparation (active in low doses) is applied to the last treatments.