羧甲基壳聚糖的制备及絮凝性能探讨

制备了具有水溶性、无毒羧甲基壳聚糖（以下简称NOCC），将其作为絮凝剂与聚丙烯酰胺（PAM）一道处理生活污水，通过测定其沉降时间，沉降絮体高度，沉降速度，沉降后溶液透光率等参数，表征了其絮凝能力，提出了普遍认为聚丙烯酰胺处理一般污水具有良好絮凝能力的不同看法，为壳聚糖的开发利用做了有益的探索。     

Transport of nitrogen oxides, carbon monoxide and ozone to the Alpine Global Atmosphere Watch stations Jungfraujoch (Switzerland), Zugspitze and Hohenpeissenberg (Germany), Sonnblick (Austria) and Mt. Krvavec (Slovenia)

The Alpine stations Zugspitze, Hohenpeissenberg, Sonnblick, Jungfraujoch and Mt. Krvavec contribute to the Global Atmosphere Watch Programme (GAW) of the World Meteorological Organization (WMO). The aim of GAW is the surveillance of the large-scale chemical composition of the atmosphere. Thus, the detection of air pollutant transport from regional sources is of particular interest. In this paper, the origin of NO_x (measured with a photo-converter), CO and O₃ at the four Alpine GAW stations is studied by trajectory residence time statistics. Although these methods originated during the early 1980s, no comprehensive study of different atmospheric trace gases measured simultaneously at several background observatories in the Alps was conducted up to present.The main NO_x source regions detected by the trajectory statistics are the northwest of Europe and the region covering East Germany, Czech Republic and southeast Poland, whereas the main CO source areas are the central, north eastern and eastern parts of Europe with some gradient from low to high latitudes. Subsiding air masses from west and southwest are relatively poor in NO_x and CO.The statistics for ozone show strong seasonal effects. Near ground air masses are poor in ozone in winter but rich in ozone in summer. The main source for high ozone concentration in winter is air masses that subside from higher elevations, often enhanced by foehn effects at Hohenpeissenberg. During summer, the Mediterranean constitutes an important additional source for high ozone concentrations.Especially during winter, large differences between Hohenpeissenberg and the higher elevated stations are found. Hohenpeissenberg is frequently within the inversion, whereas the higher elevated stations are above the inversion.Jungfraujoch is the only station where the statistics detect an influence of air rich in CO and NO_x from the Po Basin.     

水质自动监测仪中的氨气敏电极使用寿命的探讨

文章揭示了造成环境监测仪器的氨气敏电极损坏的原因，提出了延长其使用寿命的方法。首先要保护电板的引线，必须严格按照使用说明书定期进行认真的保养维护，实施氨气敏复合电极膜及其填充液的更换，保护好电极，可延长其寿命。     

Small but smart: the interaction between environmental cues and internal state modulates host-patch exploitation in a parasitic wasp

The reproductive success of insect parasitoids depends on two activities, searching for hosts to obtain immediate fitness rewards (offspring) and searching for food to extend life span and enhance future reproductive opportunities. Models suggest that to deal with this trade-off and to cope with the variability of the resources they depend on, parasitoids should simultaneously integrate information originating from three distinct sources: host and food availabilities in the environment (environmental information) and the metabolic reserves of the parasitoid (internal information). We tested whether, in the parasitic wasp Venturia canescens, these three types of information are perceived simultaneously and interact during host-patch exploitation. Experiments were performed with strains originating from two different geographical locations and with individuals of the two reproductive modes, arrhenotoky and thelytoky. We hypothesised that there would be differences between modes of reproduction as they thrive in different ecological conditions. Our results show that metabolic state, food availability and the number of ovipositions performed simultaneously modulate patch residence time in V. canescens of both populations and reproductive modes. Unfed wasps left their host patch earlier than fed ones. The tendency to leave the patch increased with an increasing probability of finding food. Our study confirms that globally, each oviposition increases the patch-leaving tendency (decremental mechanism). This effect was modulated by both the metabolic reserves and food availability, and the relationship depended on the geographic origin of populations. Individuals of one of the populations switched from a decremental to an incremental patch-leaving mechanism depending on the presence or absence of food in the vicinity. Differences between reproductive modes in the responses to environmental cues can be explained by the different ecological conditions they live in.     

Effect of particle size and dust layer size on ignition characteristics of PMMA dust layer on hot surface

Deposition of combustible dust on a hot surface is a hidden danger of fire. In this work, polymethylmethacrylate (PMMA) dust was selected to analyse the influence of dust layer diameter, dust particle size and dust layer thickness on the ignition characteristics of PMMA dust layer. Critical heating temperatures and ignition time had been measured. The STA-GC/MS-FTIR analysis was used to determine that the main products of PMMA pyrolysis were MMA, CO, CO₂, and C₂H₄, of which CO and C₂H₄ were transported to the ambient to cause gas phase combustion on the surface of the dust layer. For 10 mm thick dust layer, the critical heating temperatures of 5 μm PMMA, 100 nm PMMA, and 30 μm PMMA were 300 °C, 330 °C, and 320 °C. As the thickness of the dust layer increased, the gas transport path became longer, the critical heating temperature and ignition time increased. The characteristic particle size (D [3,2]) was utilized to represent the true particle size, and the ignition time increased with the increase of the characteristic particle size. The increase in the diameter of the dust layer had a slight effect on the temperature history and ignition time of the dust layer.     

盾构隧道内大客车人员下车试验及数值模拟研究

为研究盾构隧道火灾时大客车人员构成比例及满载系数对下车时间影响,采用现场试验及Pathfinder数值模拟,分析不同人员构成比例及满载系数下大客车人员下车过程。结果表明:不考虑人员疏散反应时间情况,大客车下车时间为54～68 s,大客车平均下车时间为60.68 s,每位人员平均下车时间为1.22 s;老人下车时间最长,成年女士下车时间最短,成年男士与儿童下车时间基本相等。当老人比例在30%~80%范围变化时,下车时间随老人比例增大显著增加;成年女士比例对大客车下车时间影响较小;大客车人员下车时间与满载系数相关,随满载系数增加而增加,并趋于正比例函数关系。     

超声对SBR工艺中剩余污泥的减量化研究

实验采用超声处理已稳定运行的SBR系统产生的剩余污泥,通过改变声能密度和作用时间对污泥进行处理,并回流至反应器,研究在不影响出水水质的前提下实现污泥减量化的条件。实验表明:在不同的声能密度和作用时间下系统出水仍可达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级排放标准,且系统污泥量稳定。在声能密度1W/mL、作用时间15min,系统运行时间为6h时,可将进水COD487mg/L降至57mg/L,MLSS维持在约3000mg/L,污泥SVI为79。     

自动增氧型垂直下行流生活污水处理器运行研究

设计一种自动增氧型垂直下行流生活污水处理器,采用间歇运行的启动方式,对比研究1号系统(完全空白系统)、2号系统(垂直下行流生活污水处理器系统)和3号系统(自动增氧型垂直下行流生活污水处理器系统)对SS、COD、TP、TN的去除效果。结果表明,经过45d的启动时间后,3号系统对SS、COD、TN、TP的4d去除率分别达到91.8%、82.4%、93.4%和91.6%,去除效果优于2号系统;3号系统在较短停留时间内就可以获得理想的去除效果。     

中国西部及周边区域电离层暴的统计特性

利用中国西部及周边9个电离层观测台站的历史数据,修正了统计研究中电离层暴事件的提取方式,在此基础上分析了区域内电离层暴的统计规律.研究表明,区域内以正暴为主,大暴主要发生在喷泉效应起作用的区域;多数台站冬季多正暴,夏季多负暴,春秋季二者相当,但在个别台站有较大差异;暴的起始时间主要分布于日落后,且在不同纬度略有差别.     

厦门市生态足迹动态分析

生态足迹（ecological footprint,EF）方法是一种衡量自然资源可持续利用的生物物理定量评价工具,能够反映出一个区域在一段时期内的可持续发展过程及其影响因子。文章基于生态足迹的理论模型,以恒定世界产量为前提,分析了厦门市1997年-2005年的生态足迹动态变化。结果表明,在这期间厦门市的人均生态足迹超过了人均生态承载力,并且两者之差（即生态赤字）不断增加。此外,通过分析总结了影响厦门市生态足迹以及生态赤字的关键性因子,这为厦门市的可持续发展决策提供了支持和依据。