基于BP神经网络的鄱阳湖水位模拟

考虑到鄱阳湖水位受流域五河与长江来水等多因素的共同作用而表现出高度非线性响应,采用典型的三层BPNN神经网络模型来模拟鄱阳湖水位与其主控因子之间的响应关系。分别将湖口、星子、都昌、棠荫和康山水位作为目标变量进行BPNN模型构建和适用性评估。结果显示：综合考虑流域五河及长江来水（汉口或九江）的BPNN水位模型,空间站点水位模拟精度（R2和Ens）可达090以上,各站点的均方根误差（RMSE）变化范围约050～10 m,若忽略长江来水的影响作用,仅将流域五河来水作为湖泊水位的主控影响因子,模型训练期与测试期的纳希效率系数（Ens）和确定性系数（R2）显著降低,且低于050,均方根误差（RMSE）也明显增大（124～288 m）,意味着综合考虑流域五河与长江来水是获取结构合理、精度保证的鄱阳湖水位模型的重要前提。同时建议针对鄱阳湖湖盆变化对水位的影响,尽可能选择一致性较好的长序列数据集来训练和测试BPNN模型。所构建的BPNN神经网络模型可进一步结合流域水文模型,用来预测气候变化与人类活动下流域径流变化对湖泊水位的潜在影响,也可作为一种有效的模型工具来回答当前鄱阳湖一些备受关注的热点问题,如定量区分流域五河与长江来水对湖泊洪枯水位的贡献分量,为湖泊洪涝灾害的防治和对策制定提供科学依据     

氧化铜尾矿对水溶液中磷的吸附

研究不同pH条件下氧化铜尾矿颗粒对水溶液中磷的吸附特性.结果表明:Langmuir方程能很好地描述氧化铜尾矿对磷素的等温吸附特征;影响氧化铜尾矿对磷素吸附的因素主要有尾矿的比表面积、钙及铁氧化物含量、水溶液中磷素的初始浓度、体系pH值等;其吸附量随着钙及铁氧化物含量的增加、磷素初始浓度的提高以及体系pH值的降低而增大;其吸附机制主要为物理吸附和化学吸附.     

Modeling the effect of daily ration and feeding frequency on growth of redtail shrimp Penaeus penicillatus (Alock) at controlled temperatures

Obtaining optimal growth of redtail shrimp at an economic production cost is essential. An experiment was conducted to evaluate simultaneous effects of daily ration and feeding frequency on growth of redtail shrimp at controlled temperatures. Two series were operated contemporarily, one at 25°C and the other at 30°C. the three daily rations were 5, 15, and 25% of fresh body weight in association with three levels of daily feeding frequency: one, three, and five times. Each series lasted for 80 days. The growth rate and the combined effects were studied on day 40 and day 80 for each series.Response surface analyses showed that, at 25°C, two quadratic polynomial equations could describe the daily growth rates (G₁ and G₂) during growth periods 1 (day 1-day 40) and 2 (day 41-day 80). The optimal daily ration and feeding frequency in terms of maximum growth rate were found at 25°C to be 22.38% of fresh body weight with three feedings/day for growth period 1 and 22.68% of fresh body weight with three feedings/day for growth period 2.At 30°C, two dynamic models were derived for each growth period that included growth optimums of 21.94% and four feedings/day for the first growth period, and 21.27% and four feedings/day for the subsequent growth period.     

平原集水区城镇化对暴雨洪水影响研究 ——以常州市双桥浜为例

城镇化下土地利用变化影响了流域洪水过程，并可能导致设计洪水发生变化。为进一步辅助城镇化流域防洪设计研究，以常州市双桥浜集水区为例，针对城镇化地区管网资料不全、区域管网河（渠）道排水过程复杂的问题，利用城市河道、道路、集水井等的汇水路径对高度城镇化小区进行子汇水区划分，基于HEC-HMS（Hydrologic Engineering Center-Hydrologic Modeling System）模型建立了适合高度城镇化下平原集水区的降雨-径流模拟模型，以模拟分析城镇化下土地利用转变对暴雨洪水的影响。结果表明，城市绿地向城镇化转变的过程较未利用地向城镇化转变使洪水增加得更大更快，且洪峰的增加幅度小于洪量的增加幅度。同时，随着土地利用转换程度的增大，对洪水影响的差异性也在增大，且低重现期洪水所表现的差异性更为明显。研究结果可为平原河网地区防洪减灾提供一定参考依据。     

中国农村人口问题与中国可持续发展

中国人口问题是中国可持续发展面临的首要问题。中国13亿人口中约有9亿是农村人口。因此所谓“中国人口问题”根本上是中国农村人口问题。人口为什么会成为一个“问题”则是关注的焦点。通过对人口问题本质进行剖析发现。研究人口问题必须着眼予人与自然的关系以及人与社会的关系。而解决中国的人口“问题”则必须着眼于农村人口生存方式的改变。从当前我国农村人口的生存方式和状况来看。中国的农村人口问题折射在农业、农村问题上。故统称为“三农”问题。为此，着眼于中国可持续发展提出解决中国农村人口问题的途径和建议。     

屠宰废水传统处理工艺的改进

把传统的物化 射流曝气活性污泥法处理屠宰废水 ,改造成AF SBR处理工艺 ,当进水SS、CODCr、BOD5、氨氮分别为 948mg L、475 9mg L、611mg L和 170 2mg L时 ,出水水质能够稳定达到《肉类加工工业水污染物排放标准》二级标准。改造后工艺技术具有针对性强 ,启动速度快 ,运行稳定可靠 ,耐冲击负荷 ,运行费用低等特点     

Monodisperse amino-modified nanosized zero-valent iron for selective and recyclable removal of TNT: Synthesis, characterization, and removal mechanism

Nitroaromatic explosives are major pollutants produced during wars that cause serious environmental and health problems. The removal of a typical nitroaromatic explosive, 2,4,6-trinitrotoluene (TNT), from aqueous solution, was conducted using a new recyclable magnetic nano-adsorbent ([email protected]₂NH₂). This adsorbent was prepared by grafting amino groups onto [email protected]₂ particles with a well-defined core-shell structure and demonstrated monodispersity in solution. The removal performance of the nano-adsorbent towards TNT was found to be 2.57 and 4.92 times higher than that towards two analogous explosives, 2,4-dinitrotoluene (2,4-DNT) and 2-nitrotoluene (2-NT), respectively, under neutral conditions. The difference in the removal performance among the three compounds was further compared in terms of the effects of different conditions (pH value, ionic strength, humic acid concentration, adsorbent modification degree and dosage, etc.) and the electrostatic potential distributions of the three compounds. The most significant elevation is owing to modification of amino on [email protected]₂ which made a 20.7% increase in adsorption efficiency of TNT. The experimental data were well fit by the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, indicating multilayer adsorption on a heterogeneous surface. The experimental results and theoretical considerations show that the interactions between [email protected]₂NH₂ NPs and TNT correspond to dipole-dipole and hydrophobic interactions. These interactions should be considered in the design of an adsorbent. Furthermore, the adaptability to aqueous environment and excellent regeneration capacity of [email protected]₂NH₂ NPs makes these remediation materials promising for applications.     

废水中GaAs、Ga~(3+)、Ge~(4+)对活性污泥脱氢酶的影响及其抑制动力学

以活性污泥脱氢酶的活性作为毒性指标,研究了半导体材料GaAs、Ga~(3+)、Ge~(4+)对活性污泥活性的抑制影响,并用Hg~(2+)作为参比材料;同时对抑制动力学也作了初步研究。实验表明,GaAs、Ga~(3+)、Ge~(4+)及Hg~(2+)的10％抑制浓度分别为45.00,371.63,0.13ppm/gMLSS,GaAs、Ga~(3+)、Ge~(4+)和Hg~(2+)在浓度分别为180,700,250和1.25ppm/g MLSS时的抑制常数分别为1.30×10~(-3),7.05×10~(-3),6.12×10~(-3)和5.49×10~(-3)mmol,且其抑制类型均属可逆非竞争性抑制。     

超滤膜处理油田采出水用于回注的试验研究

试验采用截留分子量为100 ku的PVDF(聚偏氟乙烯)超滤膜组件对大庆油田采出水进行了处理,处理水用于油田回注以减少清水的消耗和降低环境污染,同时确定了最佳操作条件和膜清洗方法并考察了超滤出水水质的影响.结果表明最佳的操作条件为:跨膜压差0.30～0.35 MPa,膜面流速3.0～3.5 m/s,温度35～40 ℃.超滤出水中的悬浮物、含油量均低于1.00 mg/L,粒径中值和SRB不能检出,超滤出水水质完全满足油田回注水标准.     

河道滞留塘系统对污染河水中氮磷的去除特性

河道滞留塘系统是一项适用于中小型污染河流净化的生态技术,目前我国部分中小型河流污染严重,研究河道滞留塘系统对河流污染物的去除特性具有现实意义,但目前尚缺乏系统深入的研究。该研究对实际污染河水进行了一年现场试验研究,通过改变水力停留时间,考察了不同季节、不同河水水质条件下河道滞留塘系统对河水中氨氮(NH3-N)和总磷(TP)的净化效果。结果表明,河道滞留塘系统主要通过颗粒物的重力沉降作用净化河水中的总磷(TP)。在该研究条件下,TP去除率接近30%,去除速率为0.01～0.02 g.h-1.m-2。TP去除速率约为0.003倍的SS去除速率,两者间有较好的相关关系,因此可通过测定滞留塘SS去除速率来预测TP去除速率。但滞留塘系统对NH3-N无显著去除能力。