化工项目环境风险分析及防范措施

本文分析了化工企业生产和储运过程中的环境风险,以及化工园区存在的环境风险,并提出了切实可行的环境风险防治对策,通过有效的防范,从而降低化工项目风险事故的发生率和对环境的影响,为化工项目风险事故的预防和管理提供技术依据。     

应用高密度电法探测北京南口-孙河隐伏断裂

举例说明了高密度电法在北京南口-孙河活隐伏活动断层勘测中的应用,展现高密度电法在断层定位中的广阔应用前景。简单介绍了高密度电法的基本原理。视电阻率异常剖面揭示南口-孙河断裂为正断层,北东盘上升,南西盘下降,推测断裂倾角60°～68°。视电阻率异常剖面与钻孔资料对应较好,并与钻探资料分析的断裂活动特性基本吻合。     

沿海城市灰霾天气与海盐氯损耗机制的关系

随着经济规模迅速扩大和城市化进程加快,大气气溶胶污染日趋严重,由细粒子气溶胶造成的能见度恶化事件越来越多,这些人类活动排放的污染物,可形成灰霾天气致使能见度下降。尤其值得注意的是沿海城市灰霾天气增长较快,沿海城市灰霾天气增多与海盐气溶胶粒子的氯损耗机制关系密切。我国30年前在粉尘污染时代建立的空气质量评价体系,已经远远不能描述新型复合空气污染类型,尤其是不能描述细粒子污染的情况,能见度的恶化主要与细粒子的浓度关系比较大,而与气溶胶的质量浓度关系不大。能见度与PM2.5尤其是PM1有非常好的关系,因而目前用能见度来描述灰霾天气是最好的指标。     

湖南省空气污染现状及防治对策

本文根据2005-2009年湖南省环境状况公报,分析了全省空气污染现状,提出了控制煤炭质量、使用清洁能源、加快产业结构调整及环境监管力度等改善空气质量的对策。     

Daily intake of 4-nonylphenol in Taiwanese

Alkylphenol polyethoxylates (APEO), alkylphenols combined with ethylene oxide, are a class of nonionic surfactants. APEO have been widely used for industrial, agricultural and household applications, and are biodegraded to more persistent and estrogen-active products, namely, nonylphenol (NP), octylphenol (OP), butylphenol (BP), nonylphenol monoethoxylate (NP(1)EO) and nonylphenol diethoxylate (NP(2)EO). This study determined NP levels in commonly consumed foodstuffs to assess daily intake of NP in a Taiwanese population. This study analyzes 318 of samples from 25 types of commonly consumed foodstuffs in northern, central, southern and eastern regions of Taiwan and estimates daily intake of NP in 466 subjects. Moreover, daily NP intake for 3915 additional subjects was estimated by analyzing data from the Nutrition and health survey in Taiwan (NAHSIT). The foodstuff samples were analyzed for five alkylphenol compounds simultaneously by HPLC with fluorescence detection. Additionally, the average compositions of typical foods consumed in Taiwan were investigated. In combination with alkylphenol levels in these foodstuffs, daily intake of NP in Taiwanese was calculated. The average daily intake of NP for the 466 subjects was 28.04+/-25.32 microg/day. Estimated daily intake of NP, based on NP levels in this study as well as the NAHSIT data, was 31.40 microg/day. Rice was the most commonly consumed source of NP, the proportion was 21.46% among daily intake of NP and the following were aquatic products and livestock, which percentage were 17.97% and 17.38%, respectively. Additionally, oysters had the highest NP levels (235.8+/-90.7 ng/g) in four regions of Taiwan, followed by salmon (123.8+/-116.2 ng/g). This study suggested that the average daily NP intake in Taiwan is 4-fold and 8.5-fold higher than daily intake in Germany and New Zealand, respectively and rice was the major source of NP intake.     

乌鲁木齐市非采暖期环境空气质量变化特征分析

通过对乌鲁木齐市2013年至2014年非采暖期主要大气污染物的浓度变化进行比较,分析了乌鲁木齐市非采暖期PM10的浓度的变化特征,为非采暖期扬尘污染的治理提供了数据基础,并提出有效治理建议。     

布袋除尘器结构改进的数值模拟研究

为了解决布袋除尘器内部流场分布不均匀、布袋局部烟气速度过高等问题,利用Fluent软件对布袋除尘器内部流场进行数值模拟,并在布袋除尘器内部设置一种新型的混合式导流板。数值模拟结果显示:在增添了混合式导流板之后,进入布袋除尘区的烟气平均速度和轴向速度都大幅减小,同时内部流场分布也更加均匀,为布袋除尘器结构改进提供了可靠的方案。     

Photodegradation of methylmercury in Jialing River of Chongqing,China

Photodegradation (PD) of methylmercury (MMHg) is a key process of mercury (Hg) cycling in water systems, maintaining MMHg at a low level in water systems. However, we possess little knowledge of this important process in the Jialing River of Chongqing, China. In situ incubation experiments were thus performed to measure temporal patterns and influencing factors of MMHg PD in this river. The results showed that MMHg underwent a net demethylation process under solar radiation in the water column, which predominantly occurred in surface waters. For surface water, the highest PD rate constants were observed in spring (12 × 10^− 3 ± 1.5 × 10^− 3 m²/E), followed by summer (9.0 × 10^− 3 ± 1.2 × 10^− 3 m²/E), autumn (1.4 × 10^− 3 ± 0.12 × 10^− 3 m²/E), and winter (0.78 × 10^− 3 ± 0.11 × 10^− 3 m²/E). UV-A radiation (320–400 nm), UV-B radiation (280–320 nm), and photosynthetically active radiation (PAR, 400–700 nm) accounted for 43%–64%, 14%–31%, and 16%–45% of MMHg PD, respectively. PD rate constants varied substantially with the treatments that filtered the river water and amended it with chemicals (i.e., Cl⁻, NO₃⁻, dissolved organic matter (DOM), Fe(III)), which reveals that suspended particulate matter and water components are important factors in affecting the PD process. For the entire water column, the PD rate constant determined for each wavelength range decreased rapidly with water depth. UV-A, UV-B, and PAR contributed 27%–46%, 6.2%–12%, and 42%–65% to the PD process, respectively. PD flux was estimated to be 4.7 μg/(m²·year) in the study site. Our results are very important to understand the cycling characteristics of MMHg in the Jialing River of Chongqing, China.     

套箍加固RC轴压中长柱的承载力理论研究∗

为研究套箍加固RC轴压中长柱的承载力理论计算分析方法,采用切线模量理论,根据材料本构关系和内外力平衡条件,推导了套箍加固RC轴压中长柱的弹塑性稳定承载力计算方法。将理论计算结果与试验结果进行了对比分析,结果表明:理论计算值均低于实测值,且二者的偏差在15%以内。根据所推导的计算分析方法,研究了核心柱初始荷载水平β、柱子长细比l0/b、套箍层混凝土强度、套箍层配筋量四种参数对加固柱承载力Nu的影响规律,结果表明:Nu总体上随β增大而减小,当β<0.7时,减小趋势不够明显,β>0.7后,减小趋势变得明显;l0/b对Nu有明显影响,Nu随l0/b的增大而减小,但二者不是线性关系;Nu随套箍层混凝土强度提高而增大,随套箍层配筋量增大而增大。     

Spatial and temporal variability of agricultural pollutants in an agricultural headwater stream within a multipond system, southeastern China

The spatial and temporal variability of nutrients and suspended solids were investigated for two years in a 1.8 km agricultural headwater stream, located by Chaohu Lake, southeastern China. The stream form was greatly modified by human activities into channelized, pond and estuary shapes. The stream could be divided into 4 channelized reaches(1.3 km), a pond reach(0.15 km) and 3 estuary reaches(0.36 km). It was found that nutrients and TSS concentrations in the stream showed temporal variability, and higher concentrations occurred in months with high precipitation and intensive agricultural activities. And, retention of total nitrogen ( TN ), nitrate ( NO3-N ),ammonium( NH4^ -N) and total suspended solids (TSS) predominantly occurred in the pond reach and estuary reaches with larger width and low current velocity. Pollutants retained in these reaches accounted for more than 50% of those retained in whole stream. The retention mostly happened in the rain-runoff events and it was 7 to 27 times than that in base flow. The results showed that the channelized reach was the most important source for pollutants release under either runoff or base flow, and its release accounted for more than 90% of whole stream release.There was a high spatial variability of nutrients retention in different channelized reaches. The channelized reach directly discharging into the pond did always retain nutrients and TSS under base flow and runoff conditions, whereas the other channelized reaches performed differently in different hydrological conditions. The high spatial and temporal variability of nutrients and TSS in the stream indicated that anthropogenic disturbance of the agricultural headwater stream, such as channelization and excavation, would be expected to decrease the capacity of nutrients retention in the stream.