WCDMA基站电磁辐射对周围环境的影响分析

随着移动通讯技术的发展,人们在享受移动通信技术带来的便捷服务同时,也在担忧通信基站产生的电磁辐射对人体健康的影响。采用选频监测仪器,对WCDMA基站在正常工作状态和最大发射功率状态下天线轴向不同距离上的功率密度进行监测,并通过理论计算进行验证,分析WCDMA基站对周围环境的影响。     

若尔盖泥炭地溶解有机碳季节变化特征及其影响因素

DOC(溶解有机碳)是泥炭地碳循环中最活跃、最敏感的指标. 以若尔盖木里苔草(Carex muliensis)泥炭地为研究对象,分析了2012年该泥炭地DOC季节变化特征及其影响因素,旨在揭示泥炭地碳循环特征及其对全球变化的潜在响应. 结果表明:若尔盖木里苔草泥炭地孔隙水中ρ(DOC)季节变化显著(P<0.001, n=12),总体呈先升后降趋势,8月和5月分别出现最高值(42.77mg/L)和最低值(26.27mg/L). DOC复合物组成结构季节变化明显,主要表现在:在整个生长季节,DOC复合物芳香组分〔A₂₅₄/ρ(DOC),其中A₂₅₄为波长254nm处的吸光度,余同〕及有色组分相对含量〔A₄₀₀/ρ(DOC)〕逐渐增加,变化范围分别为0.02~0.05和0.002~0.007;5—7月DOC复合物腐殖化程度(E4/E6,即A₄₅₀/A₆₅₀)迅速降低,8—10月又逐渐增强. 此外,土壤层温度、地表温度及相对湿度是泥炭地孔隙水ρ(DOC)季节变化的主要影响因素,三者的R2分别为0.522、0.486和0.369,降水量则对有色组分含量和腐殖化程度的季节动态有很大贡献(R分别为0.748、-0.604),同时腐殖化程度还受到土壤层和地表温度的影响(R分别为0.744、0.722). 该研究结果有利于从DOC复合物的组成结构方面进一步了解DOC季节特征及其变化的潜在机制.      

我国辐射环境自动监测系统建设的回顾与展望

辐射环境自动监测是我国辐射环境监测工作的重要内容,是核与辐射安全监管工作的重要手段.本文回顾了“十一五”以来,我国辐射环境自动监测系统建设的进展情况和在核与辐射监管工作中所发挥的作用,总结了辐射环境自动监测系统的建设和运行经验,并对今后的工作进行了展望,提出了完善系统建设和运行的合理化建议.研究指出,作为国家辐射环境监测网的重要组成部分,辐射环境自动监测系统初步具备了对我国省会城市和主要地级城市的辐射环境质量状况的实时监测能力.但由于我国辐射环境自动监测站于2008年底才开始在全国范围内建设,起步较晚、经验不足,依然存在点位数量和代表性不够、自动化程度不够高、软件系统功能不成熟、标准化和规范化问题比较突出,缺乏质量控制技术、运行维护难度大等问题.为此本文提出：第一,增加自动监测站数量,点位布设更有针对性;第二,增加自动监测站的类型;第三,加强软件系统的分析和控制能力;第四,完善相关标准、技术规范和质保体系;第五,完善运行维护体系;第六,增强国际学习和交流.     

电磁辐射污染与防护

随着电子技术的飞速发展,电磁辐射污染问题日趋严重.通过对电磁辐射的理论、危害、污染现状及其目前防治对策的研究得出:在现有的对电磁辐射环境防护措施的基础上,需要在宣传教育、环境标准的制定、环境监测手段、环境质量评价以及电磁辐射防护产品的开发几方面投入更多精力,以便更好的维护公众健康.     

输气场站工艺安全风险分析

针对输气场站HAZOP风险评估出的天然气泄漏风险进行工艺安全量化分析,通过天然气泄漏喷射火模拟,对天然气泄漏风险进行量化,为输气场站的安全管理提供有效的技术支持。通过量化,分析出对天然气泄漏喷射火造成后果大小的影响因素,提高了HAZOP风险分析的准确性和科学性,对输气场站的风险管理具有参考意义。     

电视、中波发射塔对电磁辐射环境的影响

通过对包头市城区历年的电磁环境监测,以及电视和中波发射塔周围电磁辐射情况,了解其环境质量状况和主要污染源。历年环境监测综合场强为0.30~0.47 V/m,年平均值为0.41 V/m。而广播和电视发射塔因距离而异,它们综合场强均值分别为1.26~3.43 V/m、1.44~5.34 V/m。虽然这些监测值都在标准限值之内,但可以看出广播和电视发射塔对电磁辐射综合场强的影响极大。     

Analysis of trace dicyandiamide in stream water using solid phase extraction and liquid chromatography UV spectrometry

An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.0 mL/min, and dicyandiamide was eluted with 20 mL of a methanol/acetonitrile mixture (V/V = 2:3), followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy (HPLC–UV). Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge (with activated carbon). Separation was achieved on a ZIC^®-Hydrophilic Interaction Liquid Chromatography (ZIC-HILIC) (50 mm × 2.1 mm, 3.5 μm) chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions (R² > 0.999). Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations (RSDs, n = 3) were below 6.1% with a detection limit of 5.0 ng/mL for stream water samples.     

Synergistic effect of ozonation and ionizing radiation for PVA decomposition

Ozonation and ionizing radiation are both advanced oxidation processes (AOPs) without chemical addition and secondary pollution. Also, the two processes'' efficiency is determined by different pH conditions, which creates more possibilities for their combination. Importantly, the combined process of ozonation and ionizing radiation could be suitable for treating wastewaters with extreme pH values, i.e., textile wastewater. To find synergistic effects, the combined process of ozonation and ionizing radiation mineralization was investigated for degradation of polyvinyl alcohol (PVA) at different pH levels. A synergistic effect was found at initial pH in the range 3.0–9.4. When the initial pH was 3.0, the combined process of ozonation and ionizing radiation gave a PVA mineralization degree of 17%. This was 2.7 times the sum achieved by the two individual processes, and factors of 2.1 and 1.7 were achieved at initial pH of 7.0 and 9.4, respectively. The combined process of ozonation and ionizing radiation was demonstrated to be a feasible strategy for treatment of PVA-containing wastewater.     

氯和紫外消毒过程中胞外抗性基因的产生特征

考察了城市污水氯和紫外消毒过程中不同物理形态的胞外抗性基因的产生行为与及微生物群落的关联特征.结果表明,氯消毒尽管使胞内抗性基因丰度下降,但使结合型胞外抗性基因丰度明显上升（0.7±0.1）log,而游离型胞外抗性基因丰度下降（0.2±0.1）log.紫外消毒也使胞内抗性基因下降,但使游离型胞外抗性基因显著上升（0.4±0.2）log,而结合型胞外抗性基因丰度下降（0.3±0.1）log.氯消毒后,结合型胞外DNA（a-eDNA）中变形菌门丰度下降而其他菌门的丰度上升,细菌多样性指数由4.2上升到4.7;而游离型胞外DNA（f-eDNA）中变形菌门上升了6.6%,多样性指数则从3.5降低到2.8.紫外消毒后,a-eDNA中变形菌门丰度下降了36.6%,多样性则上升到4.8,而f-eDNA中细菌丰度变化较小.分子生态网络分析揭示了抗性基因与细菌间广泛的寄存关系,tetA、tetX、sulI和sulII分别与17、15、15和5种菌属间存在共现性,表明抗性基因潜在宿主的变化是导致消毒后胞外抗性基因产生的关键原因.本研究表明氯和紫外消毒不能消除抗性基因风险,反而通过导致不同胞外抗性基因的大量产生,使风险的形式发生变化.     

Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of < 2 mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of < 10 μm within the fine particles. Zn-Cu, Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.