砖坯烧制过程中氟逸出特性研究

采用杭嘉湖地区的2种典型制砖粘土及富石灰的紫红壤为原料,通过实验室模拟试验和砖瓦厂现场测定研究了制砖中氟的逸出特性。结果表明：氟在粘土矿物发生脱羟基作用时开始逸出,温度约为600℃,主要逸出发生在约800℃至砖坯发生明显烧结时的范围内,砖瓦窑内存在可使氟逸出量减少的氟循环现象;制砖粘土性质及工艺对氟逸出存在较大影响,CaO含量高的粘土氟逸出量明显较少;中适量钙基物料、烧结料及改进制砖工艺可抑制氟的逸出。     

3种β-内酰胺类抗生素对大型溞毒性影响的研究

该研究选取阿莫西林、头孢哌酮、氨曲南3种β-内酰胺类抗生素对大型溞进行急性毒性实验和慢性毒性实验,结合大型溞的各项生命指标探讨了β-内酰胺类抗生素对大型溞的毒性效应。结果表明,阿莫西林、头孢哌酮、氨曲南对大型溞的半数致死浓度分别为129.30、141.11、29.30 mg/L。与对照组相比,3种β-内酰胺类抗生素使大型溞首次产溞时间、首次怀卵时间都呈一定的延后趋势,其每代产溞数、产溞代数、存活时间、产溞总数都有减少的趋势。相比于其他2种抗生素,氨曲南对大型溞各项生命指标的影响程度最大。3种抗生素对大型溞的毒性为氨曲南>阿莫西林>头孢哌酮。     

应用蒸汽相变促进WFGD系统脱除细颗粒的技术分析

依据蒸汽相变促进细颗粒凝并长大的机理及典型的湿法烟气脱硫(WFGD)工艺特征,提出脱硫塔出口设置蒸汽相变室,以建立细颗粒凝结长大所需要的过饱和环境,进而提高WFGD系统对细颗粒的脱除效率.综合WFGD系统的腐蚀机理及水汽不易在低表面能材料表面凝结的特性,提出采用具有良好耐腐蚀性能的低表面能材料作为凝结室的内壁面或壁面衬...     

Methods for estimating the uncertainty in emergy table-form models

Emergy studies have suffered criticism due to the lack of uncertainty analysis and this shortcoming may have directly hindered the wider application and acceptance of this methodology. Recently, to fill this gap, the sources of uncertainty in emergy analysis were described and analytical and stochastic methods were put forward to estimate the uncertainty in unit emergy values (UEVs). However, the most common method used to determine UEVs is the emergy table-form model, and only a stochastic method (i.e., the Monte Carlo method) was provided to estimate the uncertainty of values calculated in this way. To simplify the determination of uncertainties in emergy analysis using table-form calculations, we introduced two analytical methods provided by the Guide to the Expression of Uncertainty in Measurement (GUM), i.e., the Variance method and the Taylor method, to estimate the uncertainty of emergy table-form calculations for two different types of data, and compared them with the stochastic method in two case studies. The results showed that, when replicate data are available at the system level, i.e., the same data on inputs and output are measured repeatedly in several independent systems, the Variance method is the simplest and most reliable method for determining the uncertainty of the model output, since it considers the underlying covariance of the inputs and requires no assumptions about the probability distributions of the inputs. However, when replicate data are only available at the subsystem level, i.e., repeat samples are measured on subsystems without specific correspondence between an output and a certain suite of inputs, the Taylor method will be a better option for calculating uncertainty, since it requires less information and is easier to understand and perform than the Monte Carlo method.     

7种酚类化学物质对活性污泥的呼吸抑制作用

苯酚类化学物质是废水中常见的有机污染物,其对活性污泥的毒性数据对于污水处理厂稳定运行和化学品危害性评估具有重要意义。本研究采用活性污泥呼吸抑制试验(209)测定7种酚类化学物质对活性污泥的呼吸抑制作用。结果显示,2,6-二叔丁基苯酚和对特辛基苯酚对活性污泥未产生明显的毒性效应;2,4-二氯酚、2-苯基苯酚、4-硝基酚、4-氯酚和对甲酚等5种化学物质都对活性污泥呼吸有不同程度的抑制效应,3 h-EC50值分别为49.7、77.6、102、150.1和462 mg·L-1,构效关系分析结果表明-Cl、-NO2等官能团是导致活性污泥呼吸抑制效应增强的关键因素。在化学品生物降解性测试研究中,要确保有毒化学物质的测试浓度低于EC50值的1/10。     

暴雨作用下含裂缝谭家湾堆积层滑坡渗流特征与稳定性分析

堆积层滑坡在三峡库区分布广泛,该类滑坡在前期变形过程中往往产生拉张裂缝,暴雨是导致其失稳的主要诱因之一.为探究暴雨作用下裂缝优势入渗对堆积层滑坡渗流场与稳定性的影响,以谭家湾堆积层滑坡为研究对象,通过地质调查、监测数据分析以及数值模拟方法,研究了暴雨作用下含裂缝谭家湾堆积层滑坡的渗流场与稳定性演化规律.结果表明:天然条...     

Cypermethrin has the potential to induce hepatic oxidative stress, DNA damage and apoptosis in adult zebrafish (Danio rerio)

Cypermethrin (CYP), a widely used Type II pyrethroid pesticide, is one of the most common contaminants in the freshwater aquatic system. We studied the effects of CYP exposure on the induction of hepatic oxidative stress, DNA damage and the alteration of gene expression related to apoptosis in adult zebrafish. Hepatic mRNA levels for the genes encoding antioxidant proteins, such as Cu/Zn-Sod, Mn-Sod, Cat, and Gpx, were significantly upregulated when zebrafish were exposed to various concentrations of CYP for 4 or 8 days. In addition, the main genes related to fatty acid β-oxidation and the mitochondrial genes related to respiration and ATP synthesis were also significantly upregulated after exposure to high concentrations (1 and 3 μg L⁻¹) of CYP for 4 or 8 days. Moreover, in a comet assay of zebrafish hepatocytes, tail DNA, tail length, tail moment and Olive tail moment increased in a concentration-dependent manner. The significant induction (p < 0.01) of all four parameters observed with CYP concentrations of 0.3 μg L⁻¹ or higher suggests that heavy DNA damage was induced even at low levels. Furthermore, several apoptosis- related genes, such as p53, Apaf1 and Cas3, were significantly upregulated after CYP exposure, and Bcl2/Bax expression ratio decreased, especially in groups treated with 1 and 3 μg L⁻¹ CYP for 8 days. Taken together, our results suggested that CYP has the potential to induce hepatic oxidative stress, DNA damage and apoptosis in zebrafish. This information will be helpful in fully understanding the mechanism of aquatic toxicology induced by CYP in fish.     

基于互补理论的电力系统机组组合优化

针对同时具有离散和连续变量,非线性等特点的火电机组组合问题,在分析一般机组组合优化数学模型的基础上,尝试用连续化的方法建立连续变量和离散变量之间的关系,利用互补约束和最优化极值理论,构建了电力系统机组组合的互补约束优化模型。采用光滑NCP函数对建立的互补约束优化模型进行光滑处理,将其转化为一般的非线性规划问题,并用原对偶内点法进行求解。仿真结果表明:所提算法能有效处理含离散和连续变量的混合优化问题,具有很好的实际应用前景。     

基于组合赋权-可变模糊集的装配式建筑施工安全评价*

为解决装配式建筑施工安全影响因素的复杂性和模糊性,引入组合赋权和可变模糊集理论相结合的方法对装配式建筑施工安全进行评价。通过分析装配式建筑施工特点,以WSR方法论为基础,选取“人、机、法、环、管”5方面因素构建装配式建筑施工安全评价指标体系并划分指标等级标准;采用博弈论思想对G1法确定的主观权重和熵权法计算的客观权重进行最优组合,进而确定综合权重;根据可变模糊集理论量化后的级别综合特征值确定最终评价结果;将该方法用于甘肃省某装配式试点项目,评价结果与其他方法进行对比,并采用单因素轮换OAT法分析5个子系统内的指标敏感性,以便决策者识别出最敏感指标。结果表明:该实证项目安全等级为Ⅱ级,偏向Ⅲ级,与实际情况吻合;组合赋权-可变模糊集方法所得评价结果与灰色聚类分析、未确知测度方法基本一致,使评价结果准确性和稳定性得到有效提高。     

铈改性Al2O3担载Pd催化剂的CO氧化性能研究

浸渍法制备了Al2O3＋CeO2为载体的Pd催化剂,对制备中各因素对催化剂效果的影响作了初步研究。考察了活性组分含量与催化剂性能的关系以及焙烧温度、水蒸气对催化剂活性的影响。结果表明,稀土Ce元素的存在使催化剂的性能得到明显改善。制备过程中焙烧步骤对催化剂的活性影响很大,催化剂制备必须高于600℃焙烧。