深水型湖泊底泥NH4^＋-N释放的环境因子影响实验研究

通过对深水型人工湖泊（以福州市山仔水库为例）底泥NH4^＋-N释放特性进行实验研究，该实验在厌氧状态下进行，主要是以氨态氮溶出为主，这是一个物理过程，是由于分子的扩散造成的，分析了环境因子对底泥NH4^＋-N释放特性的影响及其原因。得出了温度、上覆水本身NH4^＋-N浓度和底泥粒径对底泥NH4^＋-N释放影响的动力曲线。同时说明了湖泊底泥NH4^＋-N释放对湖泊水质存在着潜在的危险性。为城市深水湖泊底泥疏浚和富营养化治理提供依据。     

SEISMIC DISASTERS IN CHINESE MAINLAND IN 2000

ＯｕｔｌｉｎｅｓｏｆｅａｒｔｈｑｕａｋｅｓｉｎＣｈｉｎａｉｎ 2 0 0 0　ＴｈｅｇｅｎｅｒａｌｌｅｖｅｌｏｆｓｅｉｓｍｉｃａｃｔｉｖｉｔｙｉｎＣｈｉｎａｉｎ 2 0 0 0ｗａｓｌｏｗｅｒｔｈａｎｉｎ 1 999,ｗｉｔｈａｔｏ ｔａｌｏｆ 50ｅａｒｔｈｑｕａｋｅｓ (Ｍｓ≥ 5.0 ) (ｓｅｅＴａｂｌｅ 1 ) ;ｂｕｔｔｈａｔｉｎＣｈｉｎｅｓｅｍａｉｎｌａｎｄｗａｓｓｌｉｇｈｔｌｙｈｉｇｈｅｒ ,ｗｉｔｈ 30ｅａｒｔｈｑｕａｋｅｓ(Ｍｓ≥ 5.0 ) ,ｉｎｃｌｕｄｉｎｇ 1 3ｑｕａｋｅｓｏｃｃｕｒｒｉｎｇｉｎＱｉｎｇｈａｉＰｒｏｖｉｎｃ…     

土地利用动态变化与生态环境效应研究——以多伦县蔡木山乡为例

采用遥感技术,对位于农牧交错带的内蒙古自治区锡林郭勒盟多伦县蔡木山乡土地利用动态变化及生态环境效应进行定性、定量相结合的研究.运用Arcview3.3地信息系统软件对研究区2000年、2010年的遥感影像进行解译,获取土地利用现状及动态变化数据,运用土地利用动态变化模型对该乡十年间的土地利用变化进行了定量研究,得出蔡木山乡土地利用变化的幅度、速度和程度等信息,就该乡的实际情况进行生态环境效应分析,以便针对实际,提出具体建议.     

Characteristics of atmospheric single particles during haze periods in a typical urban area of Beijing: A case study in October, 2014

To investigate the composition and possible sources of particles, especially during heavy haze pollution, a single particle aerosol mass spectrometer (SPAMS) was deployed to measure the changes of single particle species and sizes during October of 2014, in Beijing. A total of 2,871,431 particles with both positive and negative spectra were collected and characterized in combination with the adaptive resonance theory neural network algorithm (ART-2a). Eight types of particles were classified: dust particles (dust, 8.1%), elemental carbon (EC, 29.0%), organic carbon (OC, 18.0%), EC and OC combined particles (ECOC, 9.5%), Na-K containing particles (NaK, 7.9%), K-containing particles (K, 21.8%), organic nitrogen and potassium containing particles (KCN, 2.3%), and metal-containing particles (metal, 3.6%). Three haze pollution events (P1, P2, P3) and one clean period (clean) were analyzed, based on the mass and number concentration of PM_2.5 and the back trajectory results from the hybrid single particle Lagrangian integrated trajectory model (Hysplit-4 model). Results showed that EC, OC and K were the major components of single particles during the three haze pollution periods, which showed clearly increased ratios compared with those in the clean period. Results from the mixing state of secondary species of different types of particles showed that sulfate and nitrate were more readily mixed with carbon-containing particles during haze pollution episodes than in clean periods.     

阻塞条件下地铁隧道坡度对烟气逆流长度影响研究

在隧道纵向通风系统设计中,烟气逆流长度是至关重要的参数,传统的理论预测模型多适用于公路隧道,对阻塞条件下有坡度的地铁隧道烟气逆流长度的研究较少。通过理论分析、缩尺寸实验和FDS数值模拟,推导了适用于阻塞条件下有坡度的地铁隧道的无量纲烟气逆流长度模型,得到了烟气逆流长度随坡度的变化规律。研究结果表明,基于FDS模拟的水平地铁隧道烟气逆流长度与实验结果变化规律基本一致,该FDS模型可以研究不同坡度工况,且逆流长度随着坡度的增加呈增加趋势。     

Evaluation of the readsorption of plutonium and americium in dynamic fractionations of environmental solid samples

A dynamic extraction system exploiting sequential injection (SI) for sequential extractions incorporating a specially designed extraction column is developed to fractionate radionuclides in environmental solid samples such as soils and sediments. The extraction column can contain up to 5 g of a soil sample, and under optimal operational conditions it does not give rise to creation of back pressure. Attention has been placed on studies of the readsorption problems during sequential extraction using a modified Standards, Measurements and Testing (SM&T) scheme with four-step sequential extractions. The degree of readsorption in dynamic and conventional batch extraction systems is compared and evaluated by using a double-spiking technique. A high degree of readsorption of plutonium and americium (>75%) was observed in both systems, and they also exhibited similar distribution patterns of the two radionuclides. However, the dynamic system is fully automated, eliminates manual separations, significantly reduces the operational time required, and offers detailed kinetic information.     

某联合站轻烃回收装置职业病危害控制效果评价

目的:评估职业病防护设施防护效果,促进现场职业病防护,保护职工身体健康。方法:运用职业卫生检测法、现场调查法等方法对某建设项目进行职业病危害控制效果卫生学评价。结果:有毒物质检测均符合相关标准要求,天然气压缩机处噪声达94.3dB(A),超过职业接触限值。结论:改进噪声防护设施,达到相关标准要求。     

Fast determination of sulfonamides and their acetylated metabolites from environmental water based on magnetic molecularly imprinted polymers

Group-selective magnetic molecularly imprinted polymers (MMIPs) that can extract four widely used sulfonamide antibiotics and their acetylated metabolites from environmental water were synthesized in this study. The MMIPs with saturation magnetization value of 16.7 emu g^-1 could be separated from the environmental water samples easily by the application of an adscititious magnetic field, reducing the time consumption of pretreatment. The extraction conditions were evaluated, and optimal extraction conditions were as follows: extraction time, 25 min; amount of polymers, 90 mg; washing solvent, 30 % methanol aqueous solution; and elution solvent, methanol–acetic acid (95:5, v/v). The target analytes were detected by liquid chromatography–tandem mass spectrometry, and the detection limits of the method are in the range of 0.38–1.32 ng L^-1. The relative standard deviations of intra- and inter-day are in the range of 1.3–6.8 % and 1.7–9.1 %, respectively. The proposed method is suitable for the analysis of environmental water samples.     

Response to environmental flows in the Lower Tarim River, Xinjiang, China: an ecological interpretation of water-table dynamics

Increased water-dependent development and utilization have led to significant environmental and hydrological degradation of the Tarim River in western China and its dependent ecosystems. Between the 1950s and 1970s, 350 km of the lower reaches were drained and between 1960 and 1980 the water-table fell from between −2 and −3 m to between −8 and −10 m. Subsequently, riparian ecosystems were seriously degraded. In 2000, the Chinese government launched a program to restore the lower reaches of the river. Four environmental flows of 1034×10⁶ m³ were released from 2000 to 2002. This paper interprets and discusses the ecological significance of changes following the releases and identifies the relationship between water-table dynamics and vegetation responses. Short-term objectives for river restoration are proposed with possible monitoring parameters suggested.     

水电工程抗震设防概率水准和地震作用概率模型

本文基于我国已有的二十余个重大水利水电工程场地地震危险性分析的结果,运用概率分析方法探讨了水电工程抗震设防的概率水准和地震作用的概率模型,以便为正在修订中的《水工建筑物抗震设计规范》提供依据。