基于小波神经网络的地下水流数值模拟模型的替代模型研究

以吉林西部为研究区,建立地下水流数值模拟模型,分别应用蒙特卡罗方法和拉丁超立方方法在研究区10个县(市)开采量的可行范围内进行采样,经对比选择拉丁超立方抽样结果得到输入(开采量)—输出(水位降深)数据集,建立小波神经网络模型作为地下水流数值模拟模型的替代模型,而后对替代模型有效性作误差分析,并与多元非线性回归替代模型进行对比.结果显示,2种替代模型在功能上都能逼近地下水流数值模拟模型,但小波神经网络模型得到的水位降深均值和水位降深剩余标准差与模拟模型计算结果的相对误差分别低于多元非线性回归模型76%和45%,说明小波神经网络模型更适合作为地下水流数值模拟模型的替代模型,这为减少优化模型求解过程中直接调用模拟模型所造成的计算负荷提供了一种有效的替代方法.     

正常污泥和膨胀污泥中EPS膜污染特性及其与膜表面作用能分析

胞外聚合物(Extracellular polymeric substance,EPS)是导致膜污染的重要物质,且不同形态污泥的EPS具有不同的性质,研究正常污泥和膨胀污泥的EPS膜污染特性具有重要意义.因此,实验考察了正常污泥和膨胀污泥的膜污染速率.结果表明,膨胀污泥膜污染速率远高于正常污泥,膨胀污泥EPS(Bulking sludge-EPS,BS-EPS)浓度((172.9±10.4) mg·g-1)明显高于正常污泥EPS(Normal sludge-EPS,NS-EPS)浓度((95.9±6 6) mg·g-1),且膨胀污泥的蛋白质/多糖(Protein/Carbohydrate,P/C)值(2.26)高于正常污泥的P/C值(1 97)此外,通过序批式吸附实验研究了正常污泥和膨胀污泥的EPS膜污染差异,并基于Derjaguine-Landaue-Verweye-Overbeek (XDLVO)理论计算了EPS与PVDF膜表面之间的作用能结果表明,EPS-膜系统的总界面能为负值,即EPS-膜系统之间会发生自吸附行为,而膜与BS-EPS的总界面能(-63.943mJ.m2)较膜与NS-EPS(-56.366 mJ·m2)具有较高的能量,因此,BS-EPS与膜的吸附力较强;NS-EPS和BS-EPS主要能量壁垒分别为8.89 kT和7.51 kT,表明NS-EPS与膜之间的排斥力更强,因而BS-EPS更容易造成膜污染     

Comparative Analysis of Variation in Ecological Forms of Altai Osman, <Emphasis Type="Italic">Oreoleuciscus potanini</Emphasis> (Cyprinidae), in Lakes Ayrag,Khyargas, and Nogon (Western Mongolia)

Analysis of variation in morphological characters of Potanin Altai osman, Oreoleuciscus potanini, from two freshwater and one brackish water lakes of Western Mongolia has shown that specimens of different ecological forms—herbivorous and piscivorous—form two integral and, at the level under consideration, internally indivisible units in the system of phenetic diversity of the species O. potanini.     

Holocene Dynamics of Vegetation and Ecological Conditions in the Center of the East European Plain

Changes in the vegetation and fire regimes in the central East European Plain during the second half of the Holocene have been reconstructed based on the results of paleobotanical analysis and radiocarbon dating of material from a section of peat deposit in the Mordovia State Nature Reserve. It has been shown that birch–pine forests were widespread in the region between 7000 and 5000 yr BP, with the frequency of fires in that period being high (the fire return interval ranged from 10–20 to 100 years). Beginning from 5000 yr BP and to the early 20th century, broadleaf forests were dominant, with the fire return interval increasing to 300–500 years or longer.     

Carbon Emission from the Surface of Coarse Woody Debris in Korean Pine Forests of Southern Primorye

Carbon dioxide fluxes from the surface of coarse woody debris (CWD) have been measured in Korean pine forests of the southern Sikhote-Alin mountain range. The seasonal dynamics of oxidative conversion of CWD carbon have been evaluated, and average values of the CO₂ emission rate have been determined for CWD fragments of three tree species at different stages of decomposition. The degree of decomposition is an important factor of spatial variation in CO₂ emission rate, and temporal variation in this parameter is adequately described by an exponential function of both CWD temperature and air temperature (R² = 0.65–0.75).     

Annual Nutritional Organ Mass Cycle of <Emphasis Type="Italic">Bufo gargarizans</Emphasis> (Cantor, 1842) in Response to Extreme High Temperature

The annual relative mass of storage organs cycle of Bufo gargarizans in southwestern China was studied from December 2005 to November 2006. We described how those organs changed in response to extreme temperatures. Energy reservation dropped to the lowest levels after dormancy for both sexes, and then increased for period of 4.25 month. However, the mass of these organs dropped again rapidly until August (liver) and September (fat bodies) due to the constraint from extreme high temperature occurred during the summer, and then non-significantly increased before hibernation. For ovaries, varied with a different profile to those of liver and fat bodies have a resting period of four months. In addition, the toads’ ovaries kept growing when the mass of liver and fat bodies declining accordingly during hibernation. Therefore, ovarian mass increased during the hibernation and non-hibernation period.     

基于EEMD和EOF的鄱阳湖流域近550 a来旱涝时空变化

利用鄱阳湖流域及周边地区5个站点1467~2016年旱涝灾害史料,结合《中国近五百年旱涝分布图集》数据和现代器测降水资料,基于相关系数权重法集成重建了鄱阳湖流域近550 a旱涝序列。采用集合经验模态分解和经验正交函数等手段分析了鄱阳湖流域近550 a来的旱涝时空变化特征。结果表明：（1）鄱阳湖流域旱涝序列的各IMF分量变化规律符合自然信号的非线性变化的特征,主要的高频变化周期有2~3 a、7~8 a;中低频变化周期有22 a、36 a;低频变化周期有110 a、220 a等。（2）旱涝序列空间场的EOF分解表明,前4个模态的累积方差贡献率为93.68%,收敛效果明显。第一模态为区域整体变化一致;第二、三模态分别代表南北方向和东西方向上旱涝变化不一致;第四模态代表赣南地区的极端降水类型。（3）主要空间模态的时间系数功率谱分析结果表明,旱涝空间场模态的变化周期与旱涝序列EEMD分解的结果基本一致。 关键词： EEMD;EOF;旱涝变化;时空特征;鄱阳湖流域     

柠檬酸盐络合铜在污泥上的吸附

利用二沉池污泥进行吸附柠檬酸盐络合铜实验。研究了吸附动力学、热力学、液固比以及pH值对吸附的影响,同时对比污泥吸附前后FTIR光谱推测吸附主要基团。结果表明,吸附速率受多种机制共同影响;准二级动力学模型能较好地描述污泥吸附柠檬酸盐络合铜动力学数据;增加液固比,总铜去除率下降;偏酸性环境下污泥对络合铜吸附效果较优;吸附过程符合Langmuir等温模型;红外光谱特征分析表明,污泥含有的—OH、酰胺基、—COO-、硅酸盐物质可能是污泥吸附络合铜的主要活性基团。     

潜流湿地对典型选控性有机污染物去除的预测

建立潜流湿地有机污染物迁移转化模型,采用多孔介质模型描述潜流湿地的水力特性,并引入Monod方程相耦合,实现对湿地系统内部流场及水质浓度的同时模拟。通过实验,校核模型参数,并验证模型。结果表明,该模型能较好模拟潜流湿地中有机污染物的去除效果;计算条件下,在不同基质填料的潜流湿地中都会出现滞水区和快速通道,影响水力效率与污染物去除效果;预测了不同填料系统中7种典型选控性有机污染物的去除效果,其处理效率:苯胺苯酚二甲苯甲苯苯硝基苯氯苯,可通过优选填料提高吸附量和延长停留时间来提高选控性有机物的处理效果。     

温度和pH值对活性污泥法脱氮除磷的影响

温度和pH值是影响污水脱氮除磷效果的2个重要因素.试验采用连续搅拌槽式反应器(continuous stirred tank reactor,CSTR),通过对不同温度和pH值条件下的硝化、反硝化、释磷和吸磷反应速率的测定,总结出温度和pH值对活性污泥生化反应速率的影响规律.试验表明,硝化和反硝化速率随温度的升高而加快.在5℃和33℃时,硝化速率分别为0.01 kg NH4 -N/(kg VSS·d)和0.28 kg NH4 -N/(kg VSS·d);在5℃和30℃时,反硝化速率分别为0.097 kg NO3--N/(kg VSS·d)和0.476 kg NO3--N/(kg VSS·d);但温度对吸磷和释磷速率的影响不大.pH值对硝化、反硝化、吸磷和释磷速率均有显著影响,在pH值为7.74时,硝化速率为0.095 kg NO3--N/(kg VSS·d);而在pH值为4.9和10.08时,硝化速率仅为0.005 kg NO3--N/(kg VSS·d)和0.006 kg NO3--N/(kg VSS·d).在pH值为7.85时,反硝化速率达到最大值0.36 kg NO3--N/(kg VSS·d);而在偏酸性和碱性条件下,反硝化速率显著下降.