采用热重分析法研究煤掺烧干污泥燃烧特性

利用热重分析法对干污泥和煤及二者混合样的燃烧特性进行了研究.结果表明,在空气介质、升温速率25℃/min、温度范围20~1000℃的情况下,干污泥分别在280℃、480℃出现2个失重峰,煤在500℃时出现1个失重峰.随着干污泥掺烧比增加,混合样失重速率峰值及最大燃烧速率值增大,出现温度提前.一定比例范围的干污泥掺烧可以改善煤的着火性能,有利于煤的稳定燃烧,燃料的可燃烧性指数增加,使燃烧特性改善,该指数介于干污泥和煤单一成分燃烧特性指数之间.     

不同混合方案对气溶胶辐射特性的影响

利用体积权重平均,Maxwell-Garnett和Bruggeman理论,分别处理半径为0.5 μm 75%H₂SO₄气溶胶和黑碳气溶胶(BC),以及硫酸盐气溶胶与黑碳气溶胶内混合的情况,求出其复折射指数.利用Mie理论计算内混合单个气溶胶粒子在0.55 μm波长处的辐射特性参量,其目的在于比较分析3种不同混合方案处理的同一混合情况下内混合单个气溶胶粒子辐射特性的差别. 结果表明:辐射特性的总体变化趋势大致相同,但采用不同的混合方案处理相同的内混合情况时,其结果在黑碳混合比为10%～30%时差异较大.      

瞬时源示踪实验确定河流纵向离散系数和横向混合系数的线性回归法

本文从瞬时源二维浓度公式出发,经数学推导得出一直线方程Y=AT+B,变量Y、T可由t、c、c’_t来表示.系数A、B含有待确定的参数D_x、D_y,河流纵向和横向流速u、v,以及观测点坐标x、y.由实验观测数据(c_i,I_i通过线性回归可确定A、B,进而解二元代数方程组求出纵向离散系数D_x及横向混合系数D_y.     

京津冀与长三角地区氢氯氟碳化物本底特征

基于北京上甸子与浙江临安区域大气本底站2011—2019年氢氯氟碳化物(HCFCs)采样观测数据,开展了京津冀与长三角地区6种HCFCs(HCFC-22、HCFC-141b、HCFC-142b、HCFC-124、HCFC-132b和HCFC-133a)本底特征研究。研究结果表明:临安站HCFCs浓度水平和浓度变率比上甸子站明显更高,尤其是HCFC-133a,其浓度及浓度变率均比上甸子站高1个量级,表明长三角地区HCFCs排放量可能较京津冀地区更大。2个站点HCFCs本底浓度基本一致,差异范围为-6.1%~7.1%。上甸子站本底数据占比为26.4%~69.0%,而临安站本底数据占比不足23%。在《关于消耗臭氧层物质的蒙特利尔议定书》的约束下,2个站点多数HCFCs年均浓度呈下降趋势或变化较小。2个站点HCFC-132b浓度相对较低,但2019年相比2018年有明显升高。结合风向进行分析,发现上甸子站HCFC-22、HCFC-141b、HCFC-142b和HCFC-132b高浓度水平主要由西南扇区(北京城区方向)的WSW、SSW及SW方向贡献,而HCFC-124和HCFC-133a在各风向上的浓度和载荷差异较小。临安站HCFC-124高浓度水平主要由SSE和NNE方向贡献,分别对应金华和湖州方向;其他5种HCFCs的高浓度水平主要由东北扇区的ENE方向贡献,对应杭州城区方向。     

深水湖泊水质模型研究及其在抚仙湖中的应用

本文在深水湖泊的水质模型研究中成功地引入等效混合体积的概念，从而推导，建立一全新、实用的深水湖泊水质模型Ｃｓ＝Ｍｉｎ－ＭｏｕｔＫＶｎｙ＋Ｋ·△Ｑ＋Ｑｏｕｔｆ，并将之应用于抚仙湖。一方面证实了模型的合理性、适应性，另一方面揭示了抚仙湖水质变化的主要特征。     

西秦岭温泉岩浆混合花岗岩的地球化学特征

西秦岭温泉岩体是壳、幔岩浆混合的产物。寄主岩石(酸性端元)属铝过饱和钙碱性系列,贫CaO富FeOtotal,ANKC值大于1 1,NK/A均小于0 9,富Mo、Sn、Bi、W等高温热液成矿元素及Co、Ni、Cr等亲铁元素,LREE/HREE为10～15。基性端元暗色微细粒镁铁质包体及基性岩墙,富Na2O、K2O,而贫FeOtotal,异常富集轻稀土和Ba、Rb、Sr、Zr、Th、Hf、Nb等大离子亲石元素,而贫Co、Ni、Cr等亲铁元素,LREE/HREE为9 98～13 5,异常富轻稀土。由2端元岩浆混合形成的岩浆混合花岗岩,地球化学特征介于2端元间,并有显著的过渡特征和依从关系,反映了重要的岩浆混合信息。     

人工强制混合充氧对分层型水库细菌群落演替的影响

为深度解析人工强制混合充氧过程中细菌群落的演替，以西安金盆水库为研究对象，对2018年8月~2019年4月水库主库区垂向细菌种群结构进行连续监测.结果表明，受人工强制混合充氧作用影响，水库水体中的优势菌群蓝细菌门（Cyanobacteria）的丰度由11.7%~19.2%降至6.3%~8.9%.其中，表层、中层和底层水体蓝细菌的丰度分别由18.3%、11.7%、19.2%降至8.9%、6.3%、7.9%.人工强制混合作用使垂向水体细菌的种群结构差异降低，样本之间的离散度逐渐减小，其中优势菌群放线菌门（Actinobacteria）和变形菌门（Proteobacteria）在水体垂向的丰度分别由"中 > 底 > 表"和"表 > 底 > 中"，逐渐变为表、中、底层趋于均一.人工强制充氧作用使底部水体溶解氧（DO）含量逐渐升高，好氧型细菌的丰度得到明显的增加，其中Polynucleobacter的丰度从0.06%增加到1.06%，甲基孢囊菌属（Methylocystis）的丰度由0.18%增至2.20%，甲基杆菌属（Methylobacter）的丰度由0.02%增加到1.96%.通过冗余分析可知，影响细菌群落组成的主要因素为水体热分层稳定性、水温、DO、总磷（TP）和总氮（TN）.     

铁炭微电池电解填充流化床反应器水力学行为研究

本文提出了一种新型的铁炭微电池电解反应器———填充流化床反应器 ,并对该反应器的水力学行为进行了研究。通过床层压降法测定临界流化气速 ,建立了关于临界流化气速Uc 的经验关联式 :Uc=0 .0 15 6C0 .2 7Vt0 .14 H0 .31。通过脉冲示踪物信号法测得停留时间分布密度函数E(t) ,结果表明该反应器水力混合特性接近于完全混合反应器     

Air pollutant emissions from the asphalt industry in Beijing, China

Improving our understanding of air pollutant emissions from the asphalt industry is critical for the development and implementation of pollution control policies. In this study, the spatial distribution of potential maximum emissions of volatile organic compounds (VOCs) in the complete life cycle of asphalt mixtures, as well as the particulate matter (PM), asphalt fume, nonmethane hydrocarbons (NMHCs), VOCs, and benzoapyrene (BaP) emissions from typical processes (e.g., asphalt and concrete mixing stations, asphalt heating boilers, and asphalt storage tanks) in asphalt mixing plants, were determined in Beijing in 2017. The results indicated that the potential maximum emissions of VOCs in the complete life cycle of asphalt mixtures were 18,001 ton, with a large contribution from the districts of Daxing, Changping, and Tongzhou. The total emissions of PM, asphalt fume, NMHC, VOCs, and BaP from asphalt mixing plants were 3.1, 12.6, 3.1, 23.5, and 1.9 × 10^?3 ton, respectively. The emissions of PM from asphalt and concrete mixing stations contributed the most to the total emissions. The asphalt storage tank was the dominant emission source of VOCs, accounting for 96.1% of the total VOCs emissions in asphalt mixing plants, followed by asphalt heating boilers. The districts of Daxing, Changping, and Shunyi were the dominant regions for the emissions of PM, asphalt fume, NMHC, and BaP, while the districts of Shunyi, Tongzhou, and Changping contributed the most emissions of VOCs.     

The Importance of Mixing Height in Characterising Pollution Levels from Aerosol Optical Thickness Derived by Satellite

In the present study the horizontal distribution of columnar aerosol optical thicknessderived at high spatial resolution from Earth observation satellite data in the Lombardy area (Italy) was converted to the horizontal distribution of optically effective aerosols concentration at the ground level. This was achieved by incorporating information on atmosphere's mixing height, at which pollutants released at ground level are vertically dispersed by convection or mechanical turbulence. The resulted fields compared favourably to pollutant concentration measurements provided by the ground stations. These results show that it is possible to calculate mean concentration fields by using the spatial distribution of aerosol optical thickness (AOT) measured by satellite normalized by the atmospheric mixing height. The advantage of satellites in measuring AOT is that they can capture all actual emissions compared to the models, which are based on inventoried data.