Über d-Peptidasen in isolierten Zellkernen

The Science of Nature -     

Estimating separation distance loss probability between aircraft in uncontrolled airspace in simulation

In this article, collision probability between aircraft in uncontrolled airspace is estimated. For that purpose, a large database of aircraft trajectories in the vicinity of Saint-Cyr-l’Ecole airfield (France) is considered and maps of probability collision from simulated aircraft are then estimated. Since the collision between aircraft is a rare event, we applied an importance splitting estimation technique rather than crude Monte Carlo simulations to reduce the variance of the probability estimation. In this study, we demonstrate the high local variability of collision probability in uncontrolled airspace and conclude on the difficulty to set general probability requirements.     

污泥干化焚烧联用系统最佳运行工况研究

污泥干化焚烧联用系统将污泥焚烧产生的能量用于污泥干化,可实现污泥处理的节能降耗。对于污泥干化焚烧联用系统的运行,进厂污泥负荷、初始含水率、热值、污泥干化目标含水率是最大的影响因素。为实现污泥干化焚烧联用系统的低能耗和安全稳定运行,结合国内某污泥干化焚烧处理工程,建立了污泥干化焚烧联用系统能量和物料平衡模型,在此基础上研究了变工况条件下污泥干化焚烧联用系统的运行模式,分析了运行负荷、污泥热值、进厂污泥含水率、入炉污泥含水率发生波动时,对污泥干化单元和污泥焚烧单元所产生的影响,并提出了对应的运行策略。     

12种有机物在鲤鱼体内富集与释放行为的研究

本实验对第二松花江江水和鱼体中多次检出的12种化合物在鲤鱼(Cyprinus carpio L.)体内累积与释放行为进行了研究。提出了一个描述有机物在鱼体内富集行为的模式。给出了几种化合物生物富集因子(BCF)以及该因子与辛醇-水分配系数(K_(ow))之间的关系。研究结果表明,这些有机污染物在鱼体内的富集行为互不影响。含硝基化合物富集倍率低且易于释放,有机物是以一级动力学方式在鱼体内累积和释放。     

A framework for investigating the air quality variation characteristics based on the monitoring data: Case study for Beijing during 2013–2016

In this study, an analysis framework based on the regular monitoring data was proposed for investigating the annual/inter-annual air quality variation and the contributions from different factors(i.e., seasons, pollution periods and airflow directions), through a case study in Beijing from 2013 to 2016. The results showed that the annual mean concentrations(MC) of PM_(2.5), SO_2, NO_2 and CO had decreased with annual mean ratios of 7.5%, 28.6%, 4.6%and 15.5% from 2013 to 2016, respectively. Among seasons, the MC in winter contributed the largest fractions(25.8%～46.4%) to the annual MC, and the change of MC in summer contributed most to the inter-annual MC variation(IMCV) of PM_(2.5) and NO2. For different pollution periods, gradually increase of frequency of S-1(PM_(2.5), 0～ 75 μg/m~3) made S-1 become the largest contributor(28.8%) to the MC of PM_(2.5) in 2016, it had a negative contribution(-13.1%) to the IMCV of PM_(2.5); obvious decreases of frequencies of heavily polluted and severely polluted dominated(44.7% and 39.5%) the IMCV of PM_(2.5). For different airflow directions, the MC of pollutants under the south airflow had the most significant decrease(22.5%～62.5%), and those decrease contributed most to the IMCV of PM_(2.5)(143.3%),SO2(72.0%), NO_2(55.5%) and CO(190.3%); the west airflow had negative influences to the IMCV of PM_(2.5), NO_2 and CO. The framework is helpful for further analysis and utilization of the large amounts of monitoring data; and the analysis results can provide scientific supports for the formulation or adjustment of further air pollution mitigation policy.     

Genetic structure along a gaseous organic pollution gradient: a case study with Poa annua L

The population genetic composition of Poa annua L. was studied by starch electrophoresis along a transect running NE from an organic reagents factory at Shanghai, China. Five enzyme systems were stained. We have reached the following preliminary conclusions: (1). Organic pollution has dramatically changed genotypic frequencies at some loci of Poa annua populations. At polluted sites, significant deviations from Hardy-Weinberg equilibrium were observed on loci Sod-1 and Me due to the excess of heterozygote. Especially in the two nearest sites to pollution source, all the individuals were heterozygous at locus Sod-1. The data suggests that heterozygotes were more tolerant to organic pollution than homozygotes, indicating the fitness superiority of heterozygotes. (2). A tendency towards clinal changes of allele frequencies was found at some polymorphic loci. Frequencies of the common alleles at loci Sod-1, Me and Fe-1 increased as the distance to the pollution source increased. (3). The effective number of alleles per locus, and the observed and expected heterozygosity were much higher in the pollution series than in the clear control site (Botanic Park population), but genetic multiplicity (number of alleles per locus) was lower than for the control. (4). Most genetic variability was found within populations, and only 2.56% were among populations of the polluted series. However, 9.48% of the total genetic variation occurred among populations when including the Botanic Park population. The genetic identity between populations of the pollution series (0.9869-1.0000, mean 0.9941) was higher than those between the pollution series and the Botanic Park population. UPGMA divided the five populations into two groups. One contained the four polluted populations, and the other only contained the Botanic Park population.     

保氮增效剂调节氮肥施用量和利用率的研究 Ⅱ.保氮增效剂在小麦生产中的应用效果

利用田间试验研究了氮肥与保氮增效剂共施的效应函数和保氮增效剂促进小麦省肥增产的比较效果。同的供氮水平,保氮增效剂均能改善小麦植株经济性状,促进籽粒增产,提高氮肥报酬和施肥利润。保氮增效剂用量为氮肥实物量的5%作小麦基肥,旱地增产45～52.5kg/亩,稻田增产54.5～74.5kg/亩,氮肥报酬提高41.4～68.6%。     

城市污水处理厂各工艺阶段内分泌干扰物活性变化规律研究

使用固相萃取-酵母双杂交法研究了东北地区某污水厂内分泌干扰活性随季节的变化及不同处理单元的去除情况.结果表明,该法的EC50值为5.95×10-11mol·L-1,具有较高灵敏度.对污水水样检测得出,原污水及一沉池出水内分泌干扰活性雌二醇当量值分别为16.13～21.65和17.10～22.85ng·L-1,均以夏季最高、冬季最低;经过A/O工艺处理,二沉池出水的内分泌干扰活性降至3.37～6.76ng·L-1,以冬春较高、夏秋较低;整个污水处理工艺对内分泌干扰活性的去除率为58.1%～84.2%,平均为75.2%,也以夏季最高、冬季最低.研究还发现.二级生物处理工艺对内分泌干扰活性起主导去除作用,而一沉池对内分泌干扰物的去除能力非常有限,甚至较进水有升高现象发生.