五爪金龙凋落叶腐解物的化感潜力研究

采用莴苣种子为受体,测试了五爪金龙凋落叶早期腐解物的化感作用,并与其鲜叶及凋落叶的化感潜力进行了比较分析。结果如下:凋落叶40d的腐解物、鲜叶及凋落叶的水提取液均具有较强的化感潜力,并表现出低促高抑的浓度效应,在FW0.1g﹒mL-1高质量浓度下的综合化感抑制强度为凋落叶未能加土壤的腐解物>鲜叶>凋落叶加土壤的腐解物>凋落叶,而在FW0.005g﹒mL-1低质量浓度下的综合化感促进作用是凋落叶>鲜叶>凋落叶加土壤的腐解物>凋落叶未加土壤的腐解物。鲜叶的抑制强度较凋落叶的大,表明叶片在衰老过程中抑制作用减弱。凋落叶未加土壤仅在空气微生物作用下的腐解物抑制作用最强,促进作用最小,而加入土壤后在土壤微生物作用下的腐解物的抑制作用却有所减弱,抑制强度介于鲜叶和凋落叶的之间,促进作用却小于鲜叶和凋落叶,说明凋落叶腐解过程中微生物的参与对化感作用产生了复杂的影响。     

多氯苯生产中有机氯化物的分析

在气相色谱和色谱-质谱分析的基础上,对以六六六为原料生产多氯苯的两种工艺的产品及废渣进行了分析。结果表明:伴随多氯苯的生成,尚有多种氯化物产生。在水解生产工艺中,产品和废渣中有微量PCDDs和PCDFs,但产品中还有少量PCBs。在热解工艺中,废渣内发现大量的PCBs,PCDDs和PCDFs,最毒的异构体,2,3,7,8-TCDD含量高达24ppm。     

不同有机物料在潮棕壤中有机碳分解进程

用尼龙网袋法研究了特定年度中，不同月份间有机物料在潮棕壤旱田、水田中有机碳分解速率及C／N变化。结果表明，4种物料(玉米秸和玉米根，水稻秸和水稻根)在潮棕壤地区温度、湿度适宜的前3个月(1999年7—月)迅速分解，之后进入缓慢分解阶段，其中根的分解残留率始终高于秸秆。经计算约有2／3的玉米根和稻根腐解产物残留在土壤里；分解至试验结束。所有物料的C/N比都趋于一致，约在10—13之间，与土壤腐殖质的洲比非常相近，说明这些物料已基本完成其腐殖化过程，而成为较稳定的有机组分、这对增加土壤有机质、培肥土壤非常重要。     

The effects on waste reduction and recycling rates when different components of the waste stream are counted

States differ in the components or solid waste management activities which they include when determining solid waste reduction and recycling rates. Thus, when attempting to draw comparisons among states, confusion arises in two ways: (1) use of two types of rates; and (2) use of different components or activities when calculating a given rate. This paper presents a mathematical basis for understanding the impacts on rate calculations when variations occur in the components and activities included in those calculations. Estimates of the incremental changes occurring in the rate calculations when incineration or selected components such as yard waste, construction and demolition wastes, and junked automobiles, are added to a base of municipal solid waste constituents are found using national data. Finally, the achieved rates reported by states counting different combinations are compared.     

利用逆向轨迹反演模式估算北京地区甲烷源强

利用连续监测的大气甲烷浓度数据和拉格朗日逆向轨迹反演模式估算出北京甲烷源排放强度，并与根据最新调查数据建立的北京地区甲烷源排放清单进行了比较。排放清单结果表明，北京地区甲烷排放总量为296．4Gg/a，其中，最主要的甲烷排放源为城市垃圾和化石燃料，反映了北京作为一特大城市甲烷排放以人为源为主的特点。利用2000年6月至12月连续观测的有湿合层代表性的北京大气甲烷浓度，通过奇异值分解法（Singular Value Decomposition，SVD）反演出模拟区域的甲烷排放源强度和分布。模式计算与排放清单在甲烷源定性分布上对应较好，定量结果也是合理的。但由于可输入的气象数据有限，轨迹在整个模拟区域内覆盖不均匀，反演出的源块位置有偏差，其中偏差最大的为煤矿的甲烷排放。     

Detection of organic pollutants in sandy soils via TDR and eigendecomposition

In this study, organic pollutants in sandy soils are detected using a time domain relectrometry (TDR) probe system and eigendecomposition technique. As a demonstration, four types of organic fluids (motor oil, diesel oil, methanol and ethanol) were examined. Samples were prepared with different combinations of deionized water and organic fluid contents. For each experiment, reflected signals were captured by an oscilloscope, and their characteristics were identified using eigendecomposition technique. Autoregressive modeling and singular value decomposition methods were utilized for calculating the eigenvalues. The most significant eigenvalues were then identified based on their relative magnitude. Experimental results indicated that the presented system is sensitive to both water and pore fluid organic contents. For saturated conditions, signature curves were determined for identification of organic and/or water contents in soil pore fluids.     

Monoterpene emissions and carbonyl compound air concentrations during the blooming period of rape (Brassica napus)

An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h⁻¹ m⁻² (30–60 ng h⁻¹ per g dry plant––540–1080 ng h⁻¹ per plant), in total. Limonene, -thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (M_S) and temperature coefficients were determined: β_limonene=0.108 K⁻¹ and M_S=14.57 μg h⁻¹ m⁻²; β_sabinene=0.095 K⁻¹ and M_S=5.39 μg h⁻¹ m⁻².

The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.     

Monoterpene emissions and carbonyl compound air concentrations during the blooming period of rape (Brassica napus)

An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h⁻¹ m⁻² (30–60 ng h⁻¹ per g dry plant––540–1080 ng h⁻¹ per plant), in total. Limonene, α-thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (M_S) and temperature coefficients were determined: β_limonene=0.108 K⁻¹ and M_S=14.57 μg h⁻¹ m⁻²; β_sabinene=0.095 K⁻¹ and M_S=5.39 μg h⁻¹ m⁻².The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.     

青藏高原西北部近地表气温直减率时空分布特征

近地表气温直减率是研究山地生态系统对气候变化响应过程中的重要参数,论文基于青藏高原西北部1951—2013年的9个标准气象站以及2012—2016年的高山自设观测站的日平均气温、最低气温、最高气温（T_ave、T_min、T_max）数据,分析了青藏高原西北部近地表气温直减率（LR_Tave、LR_Tmin、LR_Tmax）的时空分布特征。结果表明：1）青藏高原西北部近地表气温随高程增大有显著下降趋势。研究区两个区域的LR_Tave、LR_Tmin、LR_Tmax均呈现出显著的空间差异性,而基于气象站的LR_Tave、LR_Tmin高于高山观测站的LR_Tave、LR_Tmin、LR_Tmax,其中LR_Tmin差异最为显著,而LR_Tmax空间差异较小。2）青藏高原西北部近地表气温直减率具有明显的季节差异,气象站的LR_Tave、LR_Tmin、LR_Tmax季节变化趋势为春季高、夏季较高、冬季低,而高山观测站的LR_Tave、LR_Tmin、LR_Tmax季节变化趋势为夏季高、冬季低。其中气象站LR_Tmax在四季中的差异最显著,而高山观测站的LR_Tmin的季节差异最大。高山观测站的气温直减率在4—9月间具有较为稳定的值。3）青藏高原西北部LR_Tave、LR_Tmin在气温突变年前后具有显著的差异,LR_Tmax无显著的变化。其中,在气温突变年之后,LR_Tave、LR_Tmin有显著的上升趋势,表明青藏高原西北部地区的LR_Tave、LR_Tmin对区域气候变化的响应显著,而LR_Tmax对区域气候变化的响应不显著。研究将有效改善青藏高原西北部气温空间分布规律研究的不足,为区域气候变化研究及生态系统对气候响应等定量研究提供理论基础。     

好氧硝化颗粒污泥搁置后活性恢复研究

利用气提式内循环间歇反应器(SBAR)考察好氧硝化颗粒污泥搁置2个月后重新投入运行, 其物理性状和微生物活性的恢复情况. 结果表明, 搁置后颗粒由棕黄色转为灰黑色, 粒径及沉降速率无明显变化. 颗粒重新投入反应器, 2周后颜色基本恢复; 污泥浓度、颗粒粒径以及沉降速率迅速增加; 颗粒中异养菌活性在1 d内即可恢复至原水平的86％, COD去除活性5 d后完全恢复, 去除率稳定在80%以上. 活性恢复阶段采用较高的曝气量和较长的循环时间有利于硝化菌的活性恢复, 第41 d曝气量由0.05 m³·h^-1提高到0.10 m³·h^-1后, 亚硝酸菌和硝酸菌活性分别由原水平的88%和82%提高到122%和92%, 氨氮去除率由之前的80% ～ 90%迅速提高到96%以上; 第65 d循环时间由4 h延长至6 h使硝酸菌的活性得到了完全恢复.