TRMM降水产品在鄱阳湖流域的精度评价

为对比TRMM 3B42 V6和V7两种版本的降水产品在鄱阳湖流域的估算精度,了解TRMM卫星资料在中国南方湿润区的应用前景,利用2003~2010年V6和V7在鄱阳湖流域的降水产品以及同期实测降水数据,从不同时间和空间尺度对比二者在鄱阳湖流域降水的估算精度。结果表明:(1)在年降水总量上,V6和V7的降水估算与实测降水差别不大,而在季和月降水尺度上,V6和V7的估算精度开始有所下降,但V7比V6结果要好一些,V7与实测降水的相关系数比V6与实测降水的相关系数高出0.1以上;(2)空间分布来看,V6和V7都能刻画出鄱阳湖流域降水自西南向东北方向递增的空间格局,但在修水流域和赣南地区,V6与实测降水偏差较大,而V7在这两个区域的降水估算精度有较大改善。总的来说,在鄱阳湖流域,V7估算的降水精度比V6有较大的提升。     

低频无极灯降解偶氮染料酸性橙7

以40 W的新型低频感应无极灯(LFEL)作为反应光源,研究了其对于水中难生化降解偶氮染料酸性橙7(AO7)的降解效果.通过专用浸没式反应器研究了这种新型光源降解AO7的有效实验参数,并与传统汞灯光源做了降解AO7的实验对比,用GC-MS检测了主要降解产物小分子,探讨了LEEL对AO7的降解机制及反应活性物质(ROS).结果表明,LFEL对于水中的AO7染料具有较好的降解效果和较高的矿化率,在浸没式反应器中曝气量2 m3·min-1,AO7浓度为20 mg·L-1(7 L)在4 h的反应后能达到94.1%的降解率,而其降解能耗远低于传统汞灯光源.降解贡献来自于两个方面:直接吸收降解和间接通过活性物质(ROS)氧化作用.氧气是ROS的重要来源,加大曝气量会提高降解效率,反应过程中有臭氧的生成.添加淬灭剂显示,·OH对降解反应几乎无贡献,1O2和O2·-则是反应的主要活性物质.     

不同粒径零价铁活化过硫酸钠氧化降解酸性橙7的影响及动力学研究

以偶氮染料酸性橙7(AO7)为目标污染物,研究了不同粒径零价铁(包括1 mm-ZVI、150μm-ZVI、50 nm-ZVI)对活化过硫酸钠(PS)氧化降解AO7的影响,并探讨了这3种不同粒径的零价铁活化体系中AO7的降解动力学及中间产物.结果表明,3种粒径零价铁均可以高效活化PS氧化降解AO7,反应90 min后,1 mm-ZVI、150μm-ZVI和50 nm-ZVI活化体系对AO7的去除率分别为43%、97%和100%.AO7动力学方程拟合结果表明,1 mm-ZVI和150μm-ZVI活化PS降解AO7是一级反应,50 nm-ZVI活化体系中AO7的降解是二级反应,这3种粒径零价铁活化PS降解AO7的速率常数大小顺序为50 nm-ZVI>150μm-ZVI>1 mm-ZVI.反应过程中1 mm-ZVI反应后主要生成α-Fe2O3和少量Fe3O4,150μm-ZVI表面的腐蚀产物主要是Fe3O4,而50 nm-ZVI的主要氧化物为α-Fe2O3和α-FeOOH.GC/MS检测出AO7降解中间产物有2-萘酚、邻甲酚、3-甲基-4-乙基苯酚、邻苯二甲酰亚胺、邻苯二甲酸等,AO7溶液吸收光谱的变化特征及GC/MS检测结果表明3种粒径零价铁活化PS氧化降解AO7的途径可能存在差异.     

Heavy Metals and Radiochemical Analyses in the Sediments of the Rapallo Harbour

To assess the natural and anthropogenic radiocontamination, sediment samples were collected in the Tigullio Gulf (Ligurian Sea). the results presented here indicate a significant Cs-137 contamination (about 20 Bqkg^-1 dry weight) while concentrations of “primordial” natural radioisotopes were similar to those detected in other coastal areas. Gross sedimentation rates, determined through measurements of Be-7 concentrations, were at about 4-5 cm in the last 6 months. Natural and artificial radioactivity concentrations have been compared with data obtained in other Mediterranean areas. Heavy metals (Cu, Cr, Mn, Ni, Zn, Pb, Cd, Hg) concentrations were also determined inside the bay. Most elements displayed quite constant concentrations through the sediment core, except for copper which had showed highest concentrations in the top 16 cm of the sediment.     

Revealing life‐history traits by contrasting genetic estimations with predictions of effective population size

Effective population size, a central concept in conservation biology, is now routinely estimated from genetic surveys and can also be theoretically predicted from demographic, life‐history, and mating‐system data. By evaluating the consistency of theoretical predictions with empirically estimated effective size, insights can be gained regarding life‐history characteristics and the relative impact of different life‐history traits on genetic drift. These insights can be used to design and inform management strategies aimed at increasing effective population size. We demonstrated this approach by addressing the conservation of a reintroduced population of Asiatic wild ass (Equus hemionus). We estimated the variance effective size (N_ev) from genetic data () and formulated predictions for the impacts on N_ev of demography, polygyny, female variance in lifetime reproductive success (RS), and heritability of female RS. By contrasting the genetic estimation with theoretical predictions, we found that polygyny was the strongest factor affecting genetic drift because only when accounting for polygyny were predictions consistent with the genetically measured N_ev. The comparison of effective‐size estimation and predictions indicated that 10.6% of the males mated per generation when heritability of female RS was unaccounted for (polygyny responsible for 81% decrease in N_ev) and 19.5% mated when female RS was accounted for (polygyny responsible for 67% decrease in N_ev). Heritability of female RS also affected N_ev; (heritability responsible for 41% decrease in N_ev). The low effective size is of concern, and we suggest that management actions focus on factors identified as strongly affecting , namely, increasing the availability of artificial water sources to increase number of dominant males contributing to the gene pool. This approach, evaluating life‐history hypotheses in light of their impact on effective population size, and contrasting predictions with genetic measurements, is a general, applicable strategy that can be used to inform conservation practice.     

基于MATLAB分析的城市道路照明环境比

基于驾驶员在行驶过程中的注意力大部分集中在车辆的正前方,忽略了道路两侧的情况的视觉特性,更容易引发交通事故的问题。环境比为评价路边物体可视度的指标,为了保证评价的准确性,尤其是保障夜间行驶的良好视觉环境,可以根据路灯设置的基本原则及照明强度与可见度的关联特性,使用MATLAB(矩阵实验室)对环境比进行模拟分析,从理论的角度研究其相关的影响因素,提出了采取减小灯具倾斜角、缩短灯具悬臂悬挑长度以及增加路灯灯杆安装位置与路缘石的距离等措施可以提高道路照明环境比的观点,可以作为路灯改造工程、路灯灯具外形的设计以及夜间行驶事故分析的理论基础。     

MATLAB在垃圾填埋气体运移数值可视化中的应用

本文基于MATLAB环境对垃圾填埋场的填埋气体运移的非线性耦合模型进行了数值可视化研究,对填埋气体在填埋场中的压力分布进行了模拟计算.结果表明,填埋气体的压力随垃圾填埋深度的增加而增大,随着填埋时间的增加,气体压力变化加快,气体压力消散程度增大.对垃圾填埋气体运移进行数值模拟不仅可为垃圾气体释放所造成的环境灾害进行评价,同时也可为填埋场气体安全控制系统的工程设计提供科学依据.     

基于MATLAB图像处理的层流火焰传播速度研究

为了减小传统本生灯火焰法测定层流预混火焰传播速度的误差,基于MATLAB图像处理技术提出了一种改进火焰图像处理及提取火焰边界线数据的方法。该方法对图像进行优化处理后运用LOG算子检测边缘信息,并为其添加平滑曲线;然后将散点拟合为函数表达式,选用Polynomial逼近方式修正拟合曲线误差;换算为实际坐标后对拟合函数进行面积积分计算,即得更接近真实的火焰外表面积。利用该方法对不同当量比下甲烷燃烧的本生灯火焰图像进行处理,求取其层流火焰传播速度,并与前人结果进行对比。结果表明,传统全面积法所得结果普遍偏高;相比于Vagelopulous利用平面火焰法所得结果,该方法获取的层流火焰传播速度在贫燃侧与之相近,在富燃侧则较之略低。     

角-并联变换法解算简单角联网络研究

在解决简单角联网络的风量分配、风阻风压计算等问题上,很少有比较简便的方法。提出了角-并联变换法,实质是将简单角联通风网络简化为简单并联网络,即将具有共同风量的分支分解为2条或几条具有等值风阻的分支巷道;然后采用BFS法(由Broyden、Flether与Shanno提出),基于MALAB编程解算变换后的网络各项通风参数,并分析等效变换精度。对解算结果的对比分析发现,运用此法求解矿井复杂风网的实算结果与Scott-Hinsley(斯考德-恒斯雷法)所得结果一致,而且更准确,表明角-并联变换的理论和方法是正确的。与传统方法相比,该方法可避免建立复杂的数学方程,在计算机上即可完成全部解算过程,除适用于解算简单角联通风网络外,也可应用于其他相关领域。