Size distribution of polycyclic aromatic hydrocarbons in urban and suburban sites of Beijing, China

PAHs in five-stage size segregated aerosol particles were investigated in 2003 at urban and suburban sites of Beijing. The total concentration of 17 PAHs ranged between 0.84 and 152 ng m(-3), with an average of 116 ng m(-3), in urban area were 1.1-6.6 times higher than those measured in suburban area. It suggested a serious pollution level of PAHs in Beijing. PAHs concentrations increased with decreasing the ambient temperature. Approximately 68.4-84.7% of PAHs were adsorbed on particles having aerodynamic diameter 2.0 microm. Nearly bimodal distribution was found for PAHs with two and three rings, more than four rings PAHs, however, followed unimodal distribution. The overall mass median diameter (MMD) for PAHs decreased with increasing molecular weight. Diagnostic ratios and normalized distribution of PAHs indicated that the PAHs in aerosol particles were mainly derived from fossil fuel combustion. Coal combustion for domestic heating was probably major contributor to the higher PAHs loading in winter, whereas PAHs in other seasons displayed characteristic of mixed source of gasoline and diesel vehicle exhaust. Biomass burning and road dust are minor contributors to the PAHs composition of these aerosol particles. Except for source emission, other factors, such as meteorological condition, photochemical decay, and transportation from source to the receptor site, should to be involved in the generation of the observed patterns.     

2,4-二氯苯酚溶液的挥发性及其处理对策

研究了温度、pH、曝气等因素对2，4-二氯苯酚溶液挥发性的影响。结果表明，高温、低pH及高曝气量可提高2，4-二氯苯酚的挥发程度。研究表明，直接电解法处理此类废水效率较低，针对此情况提出了应注意的事项及基本处理对策。     

铝型材挤压模CAD/CAE/CAM系统开发与应用

基于对型材挤压特点的详尽分析 ,提出了铝型材挤压模CAD/CAE/CAM系统功能模型并确定了基于UG和ANSYS平台的系统集成方案 ,对关键软件模块进行二次开发 ,在此基础上对平模挤压折角、槽型材和分流组合模挤压扁管型材进行了分析。     

沈阳市农田土壤农药残留水平

对沈阳市农田（水田、旱田、菜田）土壤中农药残留调查表明，禾大壮、丁草胺、敌百虫、辛硫磷、阿特拉津、乐果、氧化乐果、溴氰菊酯、１６０５残留量测定结果均低于检出限。六六六残留几何平均水平为０．０１１ｍｇ／ｋｇ．ＤＤＴ为０．０３９ｍｇ／ｋｇ；旱田、水田六六六异构体的残留主要是β－ＢＨＣ，ＤＤＴ异构体的残留主要是ｐ，ｐ＇－ＤＤＥ．     

国五国六汽车尾气颗粒物的生态毒性分析

随着汽车使用量的增加,汽车尾气的环境污染及毒性效应已引起社会的关注.我国于2016年12月23日发布了《轻型汽车污染物排放限值及测量方法（中国第六阶段）》,现阶段尚未发现国五和国六两类汽车尾气颗粒物的生态毒性及比较的研究报道.该文选取国五与国六两类汽车为研究对象,对两类汽车尾气颗粒物的排放情况及主要的半挥发性有机物（SVOCs）进行分析;选用发光菌为受试生物,研究两类汽车尾气颗粒物对发光菌的毒性效应.结果发现：①单位距离下,国五和国六汽车尾气颗粒物质量分别为（8.81±2.92）和（1.51±0.35）mg·km^-1,表明单位距离下国六汽车尾气颗粒物质量显著低于国五汽车;②在检出的SVOCs中,多环芳烃为国五和国六汽车尾气颗粒物中主要的有机污染物;③国五货车、国五轿车和国六汽车尾气颗粒物对发光菌的EC₅₀分别为42.00、41.99和5.37 mg·L^-1,表明本次的研究车辆中单位质量国六汽车尾气颗粒物的毒性高于国五汽车.研究结果表明国六标准的实施可对我国环境空气质量的改善起到重要支撑作用,下一步还应继续开展国六汽车尾气颗粒物的生态毒理学研究工作.     

Modifying glass fiber surface with grafting acrylamide by UV-grafting copolymerization for preparation of glass fiber reinforced PVDF composite membrane

Experimental design and response surface methodology(RSM) were used to optimize the modification of conditions for glass surface grafting with acrylamide(AM) monomer for preparation of a glass fiber reinforced poly(vinylidene fluoride)(PVDF) composite membrane(GFRP-CM). The factors considered for experimental design were the UV(ultraviolet)-irradiation time, the concentrations of the initiator and solvent, and the kinds and concentrations of the silane coupling agent. The optimum operating conditions determined were UV-irradiation time of 25 min, an initiator concentration of 0–0.25 wt.%,solvent of N-Dimethylacetamide(DMAC), and silane coupling agent KH570 with a concentration of 7 wt.%. The obtained optimal parameters were located in the valid region and the experimental confirmation tests conducted showed good accordance between predicted and experimental values. Under these optimal conditions, the water absorption of the grafted modified glass fiber was improved from 13.6% to 23%; the tensile strength was enhanced and the peeling strength of the glass fiber reinforced PVDF composite membrane was improved by 23.7% and 32.6% with an AM concentration at 1 wt.% and 2 wt.%. The surface composition and microstructure of AM grafted glass fiber were studied via several techniques including Field Emission Scanning Electron Microscopy(FESEM), Fourier transform infrared spectroscopy-attenuated total reflectance(FTIR-ATR) and energy dispersive X-ray spectroscopy(EDX). The analysis of the EDX and FTIR-ATR results confirmed that the AM was grafted to the glass fiber successfully by detecting and proving the existence of nitrogen atoms in the GFRP-CM.     

化学需氧量和高锰酸盐指数相关性探讨研究

选取淮河流域临沂市4个出境监测断面2014年1～11月,每月上下旬各一次化学需氧量和高锰酸盐指数浓度的分析,利用每个监测断面21对化学需氧量和高锰酸盐指数浓度的监测结果,分析了临沂境内4个出境断面两个水质参数的相关关系,给出各断面二者的一元线性回归方程及相关系数并 F检验,得出不同断面二者的相关性及因水质不同相关性的差异。通过分析同一样品的二者的监测结果的相关性,相互佐证,从多角度进行质量控制和质量保证。提出二者相关性分析结果在实际使用的建议,以期引起从事水环境监测分析、监测评价和监测管理等相关人员重视。     

A new approach for crop identification with wavelet variance and JM distance

This paper develops a new crop mapping method through combined utilization of both time and frequency information based on wavelet variance and Jeffries–Matusita (JM) distance (CIWJ for short). A two-dimensional wavelet spectrum was obtained from datasets of daily continuous vegetation indices through a continuous wavelet transform using the Mexican hat and the Morlet mother wavelets. The time-average wavelet variance (TAWV) and the scale-average wavelet variance (SAWV) were then calculated based on the wavelet spectrum of the Mexican hat and the Morlet wavelet, respectively. The class separability based on the JM distance was evaluated to discriminate the proper period or scale range applied. Finally, a procedure for criteria quantification was developed using the TAWV and SAWV as the major metrics, and the similarity between unclassified pixels and established land use/cover types was calculated. The proposed CIWJ method was applied to the middle Hexi Corridor in northwest China using 250-m 8-day composite moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index (EVI) time series datasets in 2012. The CIWJ method was shown to be efficient in crop field mapping, with an overall accuracy of 83.6 % and kappa coefficient of 0.7009, assessed with 30 m Chinese Environmental Disaster Reduction Satellite (HJ-1)-derived data. Compared with methods utilizing information on either frequency or time, the CIWJ method demonstrates tremendous potential for efficient crop mapping and for further applications. This method could be applied to either coarse or high spatial resolution images for agricultural crop identification, as well as other more general or specific land use classifications.     

溶解氧对OLAND生物膜反应器硝化性能的影响及其微生物种群动态研究

采用以多孔球悬浮填料为载体的限氧亚硝化生物膜处理高氨氮、低碳源的废水,通过对DO控制在0.5~1.0 mg/L,实现硝化阶段出水中的氨氮与亚硝态氮的比例达到最适值1∶(1.2±0.2),从而为后阶段的厌氧氨氧化系统提供理想的进水,进而提高氮的去除率;同时应用PCR-DGGE对硝化阶段不同时期的生物膜中微生物的种群动态变化进行了分析。研究表明,群落结构和优势种群的数量具有时序动态性,微生物多样性与废水的处理效果出现协同变化的特征。测序结果表明,在生物膜中进行氨氧化作用的主要为亚硝化杆菌(Ni-trosomonassp.)、亚硝化螺菌(Nitrosospirasp.);进行亚硝酸氧化的主要为硝化球菌(Nitrococcussp.)。     

超(近)临界流体溶剂在反应和分离技术中的应用

超(近)临界流体(S/NCF)具有可调性,通过调节压力和温度或加入共溶剂能够提高S/NCF溶剂中反应和分离的效率,使之具有可控性,有利于改善环境和提高经济效益本文以超临界CO₂和近临界水为例,总结了S/NCF溶剂在可持续反应和分离中的应用和研究进展.