喷嘴直径对降尘效果影响的试验研究

为提高喷雾降尘效率,以改善作业环境,有必要研究喷嘴直径与降尘效果间的关系。基于自行设计的喷雾降尘试验系统,采用马尔文实时高速喷雾粒度分析仪、高速摄像仪及粉尘浓度测定仪对不同直径喷嘴的雾化特性参数和降尘效率进行测定。结果表明,在相同喷雾压力下,随着喷嘴直径的增大,全尘降尘效率持续增加,而呼吸性粉尘降尘效率先增加后减小,并在喷嘴直径为1.5 mm时达到最大值;在耗水量相同的情况下,随着喷嘴直径的增大,全尘和呼吸性粉尘降尘效率均下降。在井下喷雾降尘中,当耗水量不受限制时,为同时确保全尘和呼吸性粉尘降尘效率,宜选择直径为1.5 mm的喷嘴;当耗水量受限制时,宜选择直径为1.2 mm的喷嘴。     

Application of an odd/even predominance of n-alkanes in oil–source rock correlation: taking the lower Paleozoic strata of the Tarim Basin as an example

The composition and distribution of n-alkanes carbon numbers reflect the source of kerogenic organic matter, sedimentary environment, and maturity of the rocks. The comparison results of the n-alkanes GC (gas chromatography) chromatograms in the Tazhong Low Uplift show that the n-alkanes of the source rocks in Upper Ordovician display an odd carbon number predominance. At the same time, Cambrian–Lower Ordovician exhibit an even carbon number predominance. The correlation between oil and source rock illustrates that crude oils in the fields of well TZ10-12 and well TZ24 stem from the Upper Ordovician source rocks. The origins of the crude oils in the fields of well TZ161-162 and well TZ45 are Cambrian–Lower Ordovician. The strata corresponding to the crude oils with odd/even carbon number predominance match the oil–source rock correlation. Thus, the characteristics of odd/even carbon number predominance in n-alkane compounds are effective for oil–source rock correlation in the Tazhong Low Uplift, Tarim Basin.     

基于水域面积法的山区河流水电站下游生态流量定值研究

水电站的大量兴建导致下游河道萎缩退化甚至断流,如何改变水电站运行调度方式,维持下游河道一定的生态流量、保障河流健康成为国内外普遍关注的问题.本文在传统水文学方法的基础上融入生物栖息地法思想,以河流生态系统的生物多样性为功能目标,用河道流量反映河流的水文过程,河道水域面积反映河流生态系统的生物多样性,创新性地提出考虑河道水文生态特性的生态流量定值方法——水域面积法.以北江上游浈江二级支流罗坝水为例进行分析计算.计算结果表明:枯水年罗坝水生态流量为2.26 m3·s-1,占多年平均流量的25.97%;平水年生态流量分月控制,生态流量过程与建站前流量过程基本一致.根据枯水年的生态流量值和平水年各月份的生态流量值,结合水电站的运行调度规则,换算成一定时期内的径流量来确定该时期内水电站需释放的水量,进而对水电站下游河道的生态功能进行保护和修复.     

Effects of water regime,crop residues,and application rates on control of Fusarium oxysporum f. sp. cubense

Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application. A laboratory experiment was conducted to develop practice guidelines on controlling Fusarium wilt, a widespread banana disease caused by Fusarium oxysporum f. sp. cubense (FOC). FOC infested soil incorporated with rice or maize straw at rates of 1.5 tons/ha and 3.0 tons/ha was incubated under flooded or water-saturated (100% water holding capacity) conditions at 30°C for 30 days. Results showed that FOC populations in the soils incorporated with either rice or maize straw rapidly reduced more than 90% in the first 15 days and then fluctuated till the end of incubation, while flooding alone without organic amendment reduced FOC populations slightly. The rapid and dramatic decrease of redox potential (down to − 350 mV) in straw-amended treatments implied that both anaerobic condition and strongly reductive soil condition would contribute to pathogen inactivation. Water-saturation combined with straw amendments had the comparable effects on reduction of FOC, indicating that flooding was not indispensable for inactivating FOC. There was no significant difference in the reduction of FOC observed in the straw amendments at between 1.5 and 3 tons/ha. Therefore, incorporating soil with straw (rice or maize straw) at a rate of 3.0 tons/ha under 100% water holding capacity or 1.5 tons/ha under flooding, would effectively alleviate banana Fusarium wilt caused by FOC after 15-day treating under 30°C.     

Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

Mercury(Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations(PNECs) for Hg(Ⅱ) and methyl mercury(Me Hg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10-3μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms,and their potential ecological risk should be respectively evaluated on the basis of mercury species.     

华阳河湖群底泥沉积物特性研究

对华阳河湖群底泥沉积物的粒径、有机质、总磷、总氮含量进行研究,探讨华阳河湖群龙感湖、黄大湖(由大官湖和黄湖组成)、泊湖三大湖区底泥污染物表层及垂向分布规律。结果表明,黄大湖污染程度最大,其底泥中有机质、总磷和总氮含量均比其它湖区要高;有机质,总磷和总氮随着深度而降低,底泥再悬浮释放污染物风险较大;在龙感湖和黄大湖中,总磷和有机质弱相关,总氮和有机质正相关,泊湖则相反,表明3个湖泊底泥沉积物中氮、磷污染负荷的来源有所不同。该研究为研究华阳河湖群内源污染负荷特征和制定湖泊污染综合整治策略提供重要的科学依据。     

北京市道路积雪污染及特性研究

通过2009~2012年对北京市区道路旁积雪的取样,分析了积雪中污染物的浓度和特性,并对国内外普遍关注的融雪剂污染问题及其控制进行了初步分析。得出道路积雪中+NH 4-N、TN、TP、COD、SS、Cd等污染物主要来自交通活动,氯化物主要来自氯盐融雪剂;与《地表水环境质量标准》相比,道路积雪中主要污染物为NH+4-N、TN、COD、BOD和氯化物,Cu、Zn、Pb、Cd等重金属的污染水平不高,可达到Ⅴ类水体标准;相同地点近似降水量条件下,积雪中TP、COD、SS的平均浓度高于降雨径流;北京市交通主干道及人行道上喷撒氯盐融雪剂的量高于国外道路,控制其污染主要通过源头减少使用量、使用替代融雪剂、严格融雪剂标准和使用方法、严肃责任追究、加强宣传教育等措施。     

安徽省农村大中型生物燃气工程现状及策略

概述了国内外开展生物燃气工程的背景,对安徽省大中型沼气工程运行模式、生产工艺、产品利用情况、运营与管理等方面进行了研究,总结了当前存在的主要问题,提出了对策。     

北京市可持续发展实验区工业领域能源利用研究

能源利用、环境保护与可持续发展问题的研究已成为一个重要课题。本文讨论了以高能耗为特征的北京市工业可持续发展问题,选取北京市可持续发展实验区的怀柔区和石景山区作为主要研究对象,针对实验区工业领域典型企业进行广泛调研,分析了高能耗工业企业能源利用情况及其特点。研究结果表明,怀柔和石景山可持续发展实验区均呈现能源消费高度集中的主要特征。此外,对代表性企业实施的余热回收和水资源循环利用等节能改造方案进行深入研究,并进行技术经济分析。继续深入挖掘潜力,为"十二五"期间可持续发展实验区工业节能工作的深化和细化奠定基础。