奥克托今在丙酮中的热安全性研究

奥克托今(HMX)作为爆速高和耐热性好的炸药被广泛应用,其制备提纯工艺均在丙酮中进行。为研究HMX在丙酮中的热安全性,用差示扫描量热-热重(DSC-TG)同步热分析仪研究HMX的热分解过程。测得升温速率为5,10,15,20℃/min的DSC和热重-微商热重法(TG-DTG)曲线,并得出分解峰温分别为279.8,282.5,284.5和288.8℃。用自行设计的临界爆温测试装置,通过小容量法测定HMX、丙酮以及HMX的丙酮溶液的临界爆炸温度。结果表明,在试验条件下,HMX的丙酮溶液的临界爆炸温度高于纯HMX的临界爆炸温度,说明丙酮抑制了HMX的热分解反应,当HMX溶液质量分数为10%时,临界爆炸温度最高,热安全性最好。     

汶川地震极震区泥石流动力特征及参数研究——以安县高川乡为例

2008年汶川8.0级地震发生以来,极震区泥石流爆发频率有增无减且规模越来越大,破坏性越来越强,严重威胁灾区人民生命财产安全。对比采取现场勘查、遥感图像分析、历史资料对比分析等方法,分析了极震区泥石流动力特征受地形、地层、物源等因素的影响,特别是泥石流爆发过程中深侵蚀和溃决对泥石流动力特征的影响。针对四川安县高川乡流域泥石流沟的调查和分析,建立泥石流流量-冲刷模型,分析了常规地区泥石流峰值流量与极震区泥石流峰值流量差别,推导出极震区峰值流量及冲刷深度定量计算公式。通过实例分析,理论与实际具有较好的一致性,对极震区泥石流动力参数计算具有较好适用性和有效性。     

Predicting heavy metals’ adsorption edges and adsorption isotherms on MnO2 with the parameters determined from Langmuir kinetics

Although surface complexation models have been widely used to describe the adsorption of heavy metals, few studies have verified the feasibility of modeling the adsorption kinetics,edge, and isotherm data with one p H-independent parameter. A close inspection of the derivation process of Langmuir isotherm revealed that the equilibrium constant derived from the Langmuir kinetic model, K S-kinetic, is theoretically equivalent to the adsorption constant in Langmuir isotherm, K S-Langmuir. The modified Langmuir kinetic model(MLK model) and modified Langmuir isotherm model(MLI model) incorporating p H factor were developed. The MLK model was employed to simulate the adsorption kinetics of Cu(II), Co(II), Cd(II), Zn(II) and Ni(II) on Mn O2 at p H 3.2 or 3.3 to get the values of K S-kinetic. The adsorption edges of heavy metals could be modeled with the modified metal partitioning model(MMP model), and the values of K S-Langmuir were obtained. The values of K S-kinetic and K S-Langmuir are very close to each other, validating that the constants obtained by these two methods are basically the same. The MMP model with K S-kinetic constants could predict the adsorption edges of heavy metals on Mn O2 very well at different adsorbent/adsorbate concentrations. Moreover, the adsorption isotherms of heavy metals on Mn O2 at various p H levels could be predicted reasonably well by the MLI model with the K S-kinetic constants.     

广西“十二五”主要污染物总量减排现状分析与探讨

实施污染物总量减排是中国环境管理和污染控制的重大举措,“十二五”后期仍是中国环境保护的重点内容,为此科学分析和制定有效的减排对策措施意义重大。通过总结广西“十二五”前三年总量减排工作现状及实施成效,从大气污染物减排、城镇污水处理、畜禽养殖污染防治、机动车氮氧化物控制、环境监管能力建设等方面分析存在问题,提出科学合理的减排对策建议：第一,突出污染减排倒逼作用;第二,严格环境准入;第三,狠抓大气污染物减排;第四,加强环保基层能力建设;第五,加强环境监管能力建设。     

极震区震后泥石流物源特征研究

汶川地震后,极震区产生了大量的崩滑堆积体、震裂岩体及震动松弛覆盖层,极震区震后泥石流物源的产生及汇集方式发生了极大的变化,但缺乏震后特殊条件下动储量的计算方法。在实际调查统计"5·12"极震区安县高川乡多条泥石沟物源的基础上,总结了极震区震后泥石流的形成过程及启动方式。分析得出,震后泥石流物源量与沟域面积、高程放大效应、断层运动方式、地质岩性条件及地形条件等因素有关,其中沟域面积、沟顶高程及沟道与发震断裂的距离为主控影响因子。在此基础上,提出了"地震高程指数放大经验模型";通过多元统计拟合法首次得出了震后泥石流动储量与流域面积、高差的计算关系,并通过地震距离修正得出极震区震后泥石流的动储量计算公式,为震后泥石流动储量估算及工程治理提供参考。     

To roll or not to roll: nyctinastic behavior in young leaves of sacred lotus,Nelumbo nucifera

The Science of Nature -     

铁炭微电解预处理电路板废水

采用铁炭微电解法预处理电路板废水.结果表明,在进水pH为2.00、铁炭质量比为4:1、振荡时间为20 min的铁炭微电解静态实验最佳条件下,絮凝出水COD去除率为30%;在进水pH为2.00、铁炭质量比为4:1、水力停留时间为50 min的铁炭微电解柱动态实验最佳条件下,连续曝气.絮凝出水COD为11021 mg/L,COD去除率约为34%,BOD5/COD从0.12上升到0.32,可生化性提高,Cu2+质量浓度从9.11 mg/L下降至0.76 mg/L,降低了废水的生物毒性,为生化处理创造了条件.     

Biosorption properties of Cd(II), Pb(II), and Cu(II) of extracellular polymeric substances (EPS) extracted from Aspergillus fumigatus and determined by polarographic method

Extracellular polymeric substances (EPS) were extracted from Aspergillus fumigatus using cationic exchange resin technique. The EPS were mainly composed of polysaccharide and low quantities of protein and nucleic acid. Biosorption of Cd(II), Pb(II), and Cu(II) of EPS was investigated as a function of pH using differential pulse polarography and the Ruzic model. Results showed that the EPS biosorption capacity determined using either the direct titration curves i?=?f(C _M) or the method proposed by Ruzic (Analytica Chimica Acta 140:99–113, 1982) were coincident. Cu(II) had the highest affinity with EPS followed by Pb(II) and Cd(II). The total number of binding sites for Cu(II) and Cd(II) increased with pH in the range of 4.0–7.0. Similar trend was observed for Pb(II) at pH?4.0–5.0, while precipitates were observed at pH?6.0 and 7.0. The conditional binding constants of these three metals displayed low levels of fluctuation with pH and ranged from 4.02?±?0.02 to 5.54?±?0.05.     

Green manure plants for remediation of soils polluted by metals and metalloids: Ecotoxicity and human bioavailability assessment

Borage, white mustard and phacelia, green manure plants currently used in agriculture to improve soil properties were cultivated for 10 wk on various polluted soils with metal(loid) concentrations representative of urban brownfields or polluted kitchen gardens. Metal(loid) bioavailability and ecotoxicity were measured in relation to soil characteristics before and after treatment. All the plants efficiently grow on the various polluted soils. But borage and mustard only are able to modify the soil characteristics and metal(loid) impact: soil respiration increased while ecotoxicity, bioaccessible lead and total metal(loid) quantities in soils can be decreased respectively by phytostabilization and phytoextraction mechanisms. These two plants could therefore be used for urban polluted soil refunctionalization. However, plant efficiency to improve soil quality strongly depends on soil characteristics.     

诱导结晶工艺中诱品载体的选择与改性

以含铜废水为处理对象，重点考察了诱晶载体的表面性质及表面负荷对诱导结晶过程的影响。结果表明，在工艺启动初期，白云石以及碱式碳酸铜为诱晶载体时，铜的去除率在90％以上，石英砂对铜的去除率较低，但石英砂经表面改性后对铜的去除效率亦可达90％以上。在运行稳定后，几类诱导载体对铜的去除率皆能稳定在95％，说明诱晶载体的表面性质对诱导结晶工艺的影响主要在于反应启动初期，选择与目标结晶产物结构、成分相同或相似的诱晶载体有利于诱导结晶过程的进行。此外，研究结果还表明，诱晶载体表面负荷对结晶过程影响较大，诱导结晶除铜工艺中载体表面负荷不宜高于0．054gCu／（m2·d）。