分子流态下翅片管式热沉传输几率计算分析

目的研究空间环境模拟器翅片管式热沉传输特性,为进一步开展真空等效性分析等研究工作奠定基础。方法根据热沉结构特点建立镜面反射气体输运通道模型,采用蒙特卡罗方法,对该模型的传输几率进行分析计算,并建立验证模型,对计算结果进行验证。结果对于所选择的翅片管式热沉,其平面阵列的传输几率为0.030 116 4,柱面阵列的传输几率为0.017 988 6。结论蒙特卡罗方法可以用于计算一定结构的翅片管式热沉的传输几率。通过传输几率的计算,可以将热沉等效为具有相应传输几率的可透射平面,从而在保证模拟精度的同时大大简化模拟计算强度,提高计算效率。     

两种不同硅铝比的ZSM-5型分子筛去除水中Pb~(2+)的研究

考察硅铝比不同的ZSM-5两种分子筛(25H和50H,25和50为硅铝比:SiO2/Al2O3)对水中Pb2+离子的吸附去除效能。两种材料均可有效吸附去除水中Pb2+离子,吸附等温线符合Langmuir吸附等温式,25H的最大吸附容量达22.22mg/g,吸附动力学符合假二阶动力学模型,吸附速率及吸附容量顺序为:25H>50H。随着投加量的增加,分子筛对Pb2+的去除率呈上升趋势。常见共存阳离子均对分子筛吸附去除Pb2+产生影响。     

Molecular toxicity of earthworms induced by cadmium contaminated soil and biomarkers screening

Earthworms (Eisenia fetida) were used to study the impact of low-dose cadmium in treated artificial soil (0, 0.6, 3, 6, 15, 30 mg/kg) and contaminated natural soil (1.46 mg/kg). The changes of earthworms' physiological related gene expressions of metallothionein (MT), annetocin, calreticulin and antimicrobial peptides were detected using real-time PCR after a 70-day incubation period. The results showed that low doses of cadmium could up regulate earthworms' MT and down regulate annetocin gene expression and show a significant positive and negative correlation respectively. The expression of two other genes, calreticulin and anti-microbial peptides, was induced at low doses of cadmium (highest gene expression at 0.6 mg/kg for calreticulin and 6 mg/kg for anti-microbial peptides) and inhibited at high doses. No significant correlation was found for these two genes. This study shows that MT and annetocin genes expression found in earthworms in contaminated soil have the potential to be developed as biomarkers of soil cadmium pollution.     

孔径调变对MCM-41分子筛吸附VOCs性能的影响

采用3种不同碳链长度的季铵盐表面活性剂C_nTAB(n=8,12,16)为模板剂,分别合成8-MCM-41、12-MCM-41和16-MCM-41介孔分子筛,并以甲苯、邻二甲苯、均三甲苯为吸附对象,考察了介孔分子筛动态吸附VOCs的性能.结果表明,通过减少表面活性剂的碳链长度,可以成功地把MCM-41分子筛的孔径调变为4.1、3.2和2.4 nm.吸附实验结果表明,当MCM-41孔径减小时,其对低浓度甲苯、邻二甲苯的吸附量大幅上升,均三甲苯存在孔道扩散效应,其吸附量增加不明显.吸附等温线表明,在2.4 nm孔道内,3种芳烃分子均属于典型的Langmuir单分子层吸附;当孔径大于2.4 nm时,芳烃分子出现明显的多层吸附和毛细凝聚现象.     

ERα和ERβ介导的有机磷农药雌激素效应差异分析

雌激素受体（Estrogen Receptor,ER）ERα和ERβ能与雌激素特异性结合,它们在结构上的差异性可能影响与类雌激素的相互作用,这进而会影响其功能.因此,针对10种有机磷农药对ERα和ERβ的雌激素效应差异,采用分子对接方法比较分析了它们与ERα、ERβ相互作用的差异并筛选出与ERα和ERβ相互作用的最佳结合模式.结果发现,10种有机磷农药分子与ERα配体结合域（Ligand Binding Domain,LBD）精氨酸（Arg394）、赖氨酸（Lys449）、色氨酸（Trp393）形成氢键;而部分农药分子与ERβLBD精氨酸（Arg346）、亮氨酸（Leu343）、赖氨酸（Lys401）形成氢键.有机磷农药配体与ERαLBDArg394、Lys449、苯丙氨酸（Phe445）、脯氨酸（Pro324）、Leu387、谷氨酸（Glu353）、甘氨酸（Gly390）等存在疏水作用,与ERβLBD氨基酸Arg346、Glu305、Leu343、蛋氨酸（Met336）、组氨酸（His279）、丙氨酸（Ala302）等存在疏水作用.采用量子化学从头算进一步分析了10种有机磷农药分子表面静电势的差异.研究发现,有机磷农药分子与ERα和ERβ受体不同的相互作用是导致雌激素效应差异的重要原因.     

A/O-MBR处理餐饮废水过程中DOM特性解析

借助凝胶过滤色谱(GFC)分子量测定技术和三维荧光(EEM)光谱技术,对厌氧微网与好氧平板膜-生物反应器(A/O-MBR)联合处理餐饮废水过程中各阶段的溶解性有机物(DOM)及污泥胞外聚合物(EPS)的性质进行研究。分子量研究表明:好氧段污泥滤液的GFC谱图中在10 min以前有大分子物质析出,分析是微生物代谢产物;且随着处理过程的进行水样DOM中的分子量分布范围不断变宽。EEM光谱研究表明:进水、好氧段出水、好氧段污泥滤液的DOM中的2种主要荧光物质为高激发波长类色氨酸和可见区类富里酸,而厌氧段出水中仅有高激发波长类色氨酸,且峰强较强。同时,厌氧段出水中在形成可见区类富里酸的区域内有成峰趋势,分析是由较强的类色氨酸峰的掩蔽作用造成的。好氧段污泥EPS中存在3个明显的荧光峰,指示了色氨酸和腐殖酸的存在。     

Kinetics of the sensitized photodegradation of nonylphenol

Nonylphenol (nonyl‐P) belongs to the classification of persistent organic pollutants. In this work we demonstrate that the contaminant suffers photooxygenation when exposed to visible light Eosin‐photosensitized irradiation. The mechanism was identified as a singlet molecular oxygen‐mediated photooxidation. Rate constants for the process, determined by time‐resolved phosphorescence detection of singlet molecular oxygen, are in the range 10⁵‐10⁷ M^‐1 s^‐1, depending on the characteristics of the reaction medium. The photooxidative process is more efficient when performed in highly polar alkaline medium.

The aggregation of nonyl‐P molecules in pure water decreases the rates of sensitized photooxidation of nonyl‐P and also those of polychlorophenolic contaminants, employed as photooxidizable model compounds, when photolyzed in the presence of nonylphenol. These results are discussed in terms of a micellar effect.     

Annual production and molecular weight as an influential factor for environmental distribution of chemicals — a case study in Japan

The changes promoted by treatment of a highly polluted soil with sulphuric acid or calcium hydroxide for changing its pH value are studied by controlling physical properties (particle size, TGA and DTA curves), evolution of metal species (exchangeable, as carbonates, related to Fe‐Mn oxides, linked to organic matter and residual) and metal uptake by plant cultures. Metal contents were determined, after wet digestion with HF—HNO₃—HC1O₄ when necessary, by AAS (Ca, Mg, Cu, Pb, Mn, Fe, Zn) or emission (Na, K). The treatment of soil with successive amounts of sulphuric leads to changes in particle size, hydration properties and exothermic peak for organic matter combustion. Very small changes were, however, detected in the alkaline treatment of soil. Soil treatments do not have practical influence on speciation of some metals (Na, K, Mg, Pb, Mn, Fe), but the intensity of the acid treatment leads to both an increase in the Cu extraction and a decrease in the Ca solubilization, probably through gypsum formation. In the case of zinc a maximum solubility in the middle of the range of acid treatment was observed. The comparison among extractants shows solubilities high for two pollutants (Pb, Cu), associated mainly to Fe—Mn oxides and organic matter, and low for two macrocomponents (Fe, K). The rest of metals, basically present in soil as carbonates or oxides, have intermediate extractions. Pot cultures weights depended mainly on both the treatment of soil (poor development in the more acid sample and drainage difficulties in the rest of acid treatments) and the situation (very low weights in laboratory runs as compared with outside), but the irrigation with water or a diluted sulphuric acid solution (at pH = 4.0) did not produce significant weight changes. Tendencies to increase plant pollution were observed for smaller soil pH, acid irrigation and probably for outside cultures, due to uptake by leaves.     

Fe(II)、Fe(III)对砷与不同分子量腐植酸络合性能的影响

以腐植酸（HA）代表天然有机质,采用平衡透析和超滤的方法研究铁离子（Fe （II）、Fe （III））对不同分子量HA与砷离子（As （V）、As （III））络合作用的影响,并利用红外光谱（FT-IR）表征其络合特征.结果发现,Fe （II）和Fe （III）均能增强HA络合As能力,且对As （V）络合能力的增强作用大于As （III）;pH值显著影响HA络合As能力;溶解性有机碳（DOC）浓度由5mg/L增大到200mg/L,As络合百分比随之增加,此时HA-Fe （III）络合As （III）百分比最大,为24.55%;初始As浓度由10μg/L增加1000μg/L,As络合百分比随之降低,其中HA-Fe （III）络合As （III）百分比最低,为3.11%.相同环境条件下,分子量>100kDa络合As百分比最大,其中HA-Fe （II）络合As （III）的百分比最高为26.43%;分子量小于10kDa的HA络合As百分比明显高于其他分子量的HA.Fe的增强作用主要源于Fe与羧基形成桥梁再与As络合形成三元络合物.     

壳聚糖在活性污泥中的可生化性研究

以不同分子量和不同脱乙酰度的壳聚糖为对象,研究了壳聚糖溶液的COD和BOD5分别随分子量和脱乙酰度变化的规律,并将其应用于活性污泥法废水处理,研究了不同分子量和不同脱乙酰度的壳聚糖对微生物活性的影响及其抑菌作用.由壳聚糖溶液的BOD5/COD及其对微生物活性的影响初步得出壳聚糖在活性污泥中是不可生化的.