静态光催化去除甲醛及其分解产物的研究

以静态光催化去除甲醛,研究光催化过程中温度、相对湿度、一氧化碳和二氧化碳浓度的变化情况．结果表明,光催化降解相对于光催化剂吸附去除来说可以更有效地去除空气中的甲醛,但是温度、相对湿度、一氧化碳和二氧化化碳浓度都会随之升高,尤其是产物中存在一氧化碳,使得光催化的副产物造成更严重的二次污染并降低催化的活性．     

Examining the interpersonal process and consequence of leader–member exchange comparison: The role of procedural justice climate

Individuals are always sensitive to their relative standing in interpersonal comparison processes of leader–member exchanges (LMXs) in teams. Little research, however, has investigated whether coworkers with a higher LMX influence the emotional and behavioral reactions of individuals with a lower LMX in different dyads. Drawing on social comparison theory and the symbolic model of procedural justice (PJ) climate, we conducted 2 independent studies—an experimental study focusing on the self‐perceived upward LMX comparison (i.e., an individual perceives that a coworker's LMX is higher than the LMX that he or she has with the supervisor; N = 203; Study 1: American working adults) and a field survey study focusing on the other‐perceived downward LMX comparison (i.e., a coworker perceives that his or her own LMX is higher than the LMX that the individual has with the supervisor; N = 177; Study 2: Chinese software engineers). Results from these studies consistently revealed that a coworker's higher LMX elicits an individual's hostile emotions when the PJ climate is low but that this relationship is buffered when the PJ climate is high. Results of both studies also showed that the coworker's higher LMX arouses the individual to direct harmful behavior toward that coworker (via the individual's feelings of hostility) when the PJ climate is low but not when it is high.     

Application of different single extraction procedures for assessing the bioavailability of heavy metal(loid)s in soils from overlapped areas of farmland and coal resources

Heavy metal(loid) extraction from soils in overlapped areas of farmland and coal resources (OAFCR) is crucial in understanding heavy metal bioavailability in soil and the subsequent risks to crops and consumers. However, limited attention has been paid to the extraction procedure of heavy metal(loid)s in OAFCR soils in the research. This study therefore explored different single and mixed extraction procedures, such as acetic acid (HOAc), citric acid, ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA), ethylene diamine tetraacetic acid + ammonium acetate (EDTA+NH₄OAc), and total digestion (HNO₃-HClO₄-HF) to determine the bioavailability of As, Cd, Cr, Cu, Pb, and Zn in OAFCR soil in Xuzhou, China. The results showed the metal(loid) extraction capacity from soil of the different procedures could be ranked as AB-DTPA > EDTA+NH₄OAc > HOA_C > citric acid. The transfer ability of heavy metal(loid)s from soil to wheat tissues and from wheat roots to aerial parts was analyzed by calculating the bioconcentration factor and transfer factor, respectively. Transfer factors of all metal(loid)s were < 1 except Cr whose transfer factor from root to shell and straw were > 1. It is suspected that foliar uptake plays a dominant role in Cr uptake. Correlation analysis between the bioavailability of heavy metal(loid)s in soil and uptake in respective wheat tissues was performed to recommend the best extraction procedures for different studies. The results show that AB-DTPA extraction is recommended for Cu uptake to wheat roots, straws, shells and grains, Zn uptake to roots, and Cd uptake to roots and straws.

     

基于FITNET FFS模型的腐蚀管道失效概率敏感性分析

为了获取影响腐蚀管道失效概率的关键因素及敏感性规律,基于FITNET FFS模型,采用可靠性理论对国内某腐蚀管道的失效概率进行计算和分析。通过全寿命方法计算了腐蚀增长速率,从而得到了与时间相关的腐蚀管道损伤概率模型,并采用蒙特卡罗模拟算法进行求解,得出了不同年限下腐蚀管道的失效概率;采用变异系数法对各影响因素进行参数敏感性分析。研究结果表明:管道直径、壁厚及径向腐蚀速率的分散性对管道失效概率具有双向扰动作用,其机理在于随机变量的分散性和腐蚀速率同时影响失效概率的波动,开始阶段随机变量分散性起主导作用,两者在管道失效概率达到50%会趋于一个平衡状态,之后腐蚀速率起主要支配作用;另外,管材的抗拉强度对腐蚀管道失效概率的影响较屈服强度的影响更大,可靠性分析时采用只考虑屈服强度的强度模型将存在一定的局限性,建议同时考虑管材抗拉强度的影响。     

基于气象因子的PM_(2.5)回归预测模型研究

采用Pearson相关系数分析了2013—2016年3大典型城市北京、南京和广州的ρ(PM_(2.5))与各气象因子的关系。结果表明,3个城市ρ(PM_(2.5))与各风速因子最大的相关系数依次为-0.44,-0.29和-0.37,与各气温因子最大的相关系数依次为-0.44,-0.33和-0.37,气压与南京和广州的ρ(PM_(2.5))正相关,气压因子最大的相关系数分别为0.25和0.34,湿度与北京ρ(PM_(2.5))正相关,与广州ρ(PM_(2.5))负相关,湿度因子最大的相关系数分别为0.49和-0.36,日照时数与北京ρ(PM_(2.5))相关系数为-0.46,降水量与南京和广州ρ(PM_(2.5))相关系数分别为-0.20和-0.24;采用逐步线性回归方法建立城市次日ρ(PM_(2.5))与气象因子的预测模型,复合相关系数分别为0.722 8,0.770 6和0.809 9。模型预测3个城市2016年PM_(2.5)年均值分别偏高4,5和3μg/m3,日均值平均相对误差为±45.6%,±32.9%和±26.0%,模型对高ρ(PM_(2.5))普遍低估。     

近50年金沙江各区段年径流量变化及分析

为深入探究不同自然地理条件下金沙江流域的径流特性,将屏山站以上区域分为6个区段,采用线性倾向估计、Spearman秩次相关检验、Mann Kendall检验、有序聚类分析、秩和检验等方法,分析了1960~2015年各区段径流序列,并结合流域的水文要素和人类活动情况讨论了影响径流量变化的因素。结果表明: 近50 a仅直门达以上区段和华弹-屏山区段径流变化在全时段有显著趋势,分别是上升和下降;但在近20 a中下游的石鼓-攀枝花、攀枝花-华弹、华弹-屏山区段均呈现明显的下降趋势。90年代后多个区段经历了突变。分析表明降水是近50 a来径流变化的主要驱动因素;其中石鼓站以上区段和雅砻江流域受降水影响最大。没有充足证据表明持续上升的气温对各区段径流量造成足够的影响。进入21世纪后,以水土保持措施为代表的人类活动是下游攀枝花-华弹、华弹-屏山区段径流减少的重要因素,但主导因素仍为降水。此外,雅砻江流域和华弹-屏山区段内大型水库投运前的初期蓄水对当年径流量有显著影响;蓄水后的水库蒸发及引水工程的损失对径流影响则相对较小。     

农户认知、外部环境与绿色农业生产意愿——基于湖北省632个农户调研数据

以湖北省632个农户调研数据为实证,在考虑绿色农业生产外部环境的情况下,结合农户对绿色农业生产的认知和农户特征因素,利用logistic回归探析农户绿色农业生产意愿的影响因素。结果表明:（1）农业收入占家庭总收入比重、绿色技术的经济效益和了解程度、农村环境污染现状、政府补贴都对农户绿色农业生产意愿具有正向影响;（2）农户年龄、绿色技术采用风险和政府管制则会减弱农户的绿色生产意愿。因此在推进农业生产绿色化转型的过程中,应加强职业农民培育和绿色农业生产技术的宣传培训,确保绿色技术的适用可靠性。同时政府应加强完善农业绿色生产制度,通过激励政策替代管制和惩罚机制,引导和规范农户绿色农业生产行为     

大九湖泥炭磁化率及腐殖化度记录的18.7 Ka BP气候变化

神农架大九湖泥炭沼泽是中纬度亚热带地区的高山泥炭沼泽,其连续沉积的泥炭剖面蕴含了丰富的气候变化信息,对揭示我国中纬度地区不同时间尺度的气候环境变化有着重要意义。使用碱提取溶液吸光度法对大九湖泥炭吸光度进行测定,以E4/E6比值表征腐殖化度,同时测定了泥炭的磁化率,通过AMS14C测年技术建立了神农架大九湖泥炭地的年代序列,结合区域的其他气候代用指标,分析大九湖泥炭磁化率与腐殖化度E4/E6的古气候意义：大九湖泥炭频率磁化率值高指示气候冷干,降水量小;磁化率值偏低指示气候暖湿,降水量大。E4/E6值高,腐殖化度低,指示气候冷干;值低,腐殖化度高,指示气候暖湿。探讨大九湖地区末次冰消期以来的气候变化,重建该区18.7 Ka BP 的气候演化过程：末次冰期结束期（18.7~11.7 Ka BP）气候比较冷干,期间存在气候冷暖干湿交替波动;全新世（11.7~0 Ka BP）以来,气温开始回升,气候比较暖湿,期间也存在突发性降温事件,其中,全新世早期（11.7~9.3 Ka BP）气候冷暖干湿交替波动,总体冷湿;全新世中期（9.3~3.5 Ka BP）气候暖湿;全新世晚期（3.5~0 Ka BP）气候温干。 关键词： 泥炭;磁化率;E4/E6;大九湖;气候变化     

污泥掺烧对焚烧后固体废物污染物排放的影响

在佛山某生活垃圾焚烧发电厂开展生活垃圾掺烧市政污泥工业试验,分析5%、10%、15%的市政污泥掺烧对电厂焚烧后固体废物中重金属和二噁英排放的影响。结果表明,掺烧污泥使Cd在飞灰中的分布提高了40%以上,但其他重金属的分布特征仍主要受各自沸点的影响。焚烧固废中重金属含量受污泥的引入影响普遍不显著,飞灰中Cu浸出质量浓度上升20%,Ni、Pb、Hg、Cr的浸出质量浓度波动下降;炉渣中重金属浸出质量浓度波动较大。焚烧飞灰中总二噁英含量与污泥掺烧比例成负相关,且与投料中的Cl质量分数成正相关,与S质量分数成负相关。因此,低于15%的污泥掺烧比例不会显著提升焚烧固废中污染物排放浓度。