乐安江漫滩区稗草中重金属污染和来源分析

2005年10月,采集了乐安江及其支流漫滩区表层土中的优势植物--稗草,并测定了其中6种重金属(Cd、Cr、N i、Cu、Pb、Zn)的含量。流经亚洲最大露天铜矿(德兴铜矿)的乐安江,其三条支流由于被德兴铜矿的酸性矿山废水(AMD)和一个活性炭厂排出的废液所污染,以至其漫滩区表层土中的稗草含有高浓度的Cd、Cu、Pb、Zn。稗草中6种金属的生物体内累积性按下列次序退减:Cd>Zn>Cu>Pb>N i>Cr,这与它们在环境中的迁移性相一致。     

Highly conductive and transparent carbon nanotube-based electrodes for ultrathin and stretchable organic solar cells

In this work, we have presented a freestanding and flexible CNT-based film with sheet resistance of 60 ?/ and transmittance of 82% treated by nitric acid and chloroauric acid in sequence. Based on modified CNT film as a transparent electrode, we have demonstrated an ultrathin, flexible organic solar cell(OSC) fabricated on 2.5-μm PET substrate. The efficiency of OSC, combined with a composite film of poly(3-hexylthiophene)(P3HT) and phenyl-C61 butyric acid methyl ester(PCBM) as an active layer and with a thin layer of methanol soluble biuret inserted between the photoactive layer and the cathode, can be up to 2.74% which is approximate to that of the reference solar cell fabricated with ITO-coated glass(2.93%). Incorporating the as-fabricated ITO-free OSC with pre-stretched elastomer, 50% compressive deformation can apply to the solar cells. The results show that the as-prepared CNT-based hybrid film with outstanding electrical and optical properties could serve as a promising transparent electrode for low cost, flexible and stretchable OSCs, which will broaden the applications of OSC and generate more solar power than it now does.     

ICP-AES测定湖泊沉积物中微量元素的样品微波消解研究

为正确测定鄱阳湖沉积物中微量元素而研究样品消解方法,采用密闭式微波消解系统处理样品,以ICP-AES法测定多种微量元素.分别从不同的消解液、用酸量、消解工序以及样品消解量等方面进行研究和优化,最终确定了一个最适合消解鄱阳湖沉积物的前处理消解体系为:消解样用量为0.5 g,180℃电热板上预处理约15 min,消解体系选择酸比例为4:4:2的HNO3-HF-H2O2体系和HNO3-HF-HClO4体系均可,消解工序为5 atm/3 min-10 atm/2 min-15 atm/5 min-20 atm/10 min的逐步加热工序.这种消解方法简单快速、效率高、劳动强度低,为以后鄱阳湖沉积物的测定做了样品准备工作.     

赣江流域水体无机氮分布特征

于2006年1月和7月对赣江流域地表水进行了系统采集,分析研究了水体中各形态无机氮分布特征,结果表明,赣江水体中主要的氮素形式是NO-3-N,枯水期赣江流域NO-3-N、DIN从上游至下游呈明显的上升趋势,NH 4-N变化不明显.丰水期从上游至下游NO-3-N含量逐渐降低,但降幅不大,而NH 4-N和DIN在中游含量最低,下游最高.主要支流中枯水期以袁水NO-3-N和DIN含量最高,赣江中支NH 4-N含量为全流域最大值,而丰水期以禾水NO-3-N为流域最高值.赣江主干流丰水期各形态无机氮含量明显低于枯水期.氮污染较重的袁水的输入致使G38(樟树)处氮含量明显高于其它地方.     

Highly flexible and excellent performance continuous carbon nanotube fibrous thermoelectric modules for diversified applications

A highly flexible and continuous fibrous thermoelectric (TE) module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber, which effectively avoids the drawbacks of traditional inorganic TE based modules. The maximum output power density of a 1-cm long fibrous TE module with 8 p-n pairs can reach to 3436 μW·cm^-2, the power per unit weight to 2034 μW·g^-1, at a steady-state temperature difference of 50 K. The continuous fibrous TE module is used to detect temperature change of a single point, which exhibits a good responsiveness and excellent stability. Because of its adjustability in length, the flexible fibrous TE module can satisfy the transformation of the temperature difference between two distant heat sources into electrical energy. Based on the signal of the as-fabricated TE module, a multi-region recognizer has been designed and demonstrated. The highly flexible and continuous fibrous TE module with excellent performance shows a great potential in diversified applications of TE generation, temperature detection, and position identification.     

Performance improvement of continuous carbon nanotube fibers by acid treatment

Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers' properties.After HCISO_3 treatment for 2 h,the fibers' strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G' band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.     

鄱阳湖周边几种养殖水体的富营化现状及对水环境影响

采用综合指数法对鄱阳湖水产养殖水体营养状态进行了综合评价。通过评价得出:鄱阳湖区的水产养殖水体已经产生了富营养化,蚌类养殖水体属于极富营养;蟹类养殖水体属于中富营养;鱼类养殖水体属于中营养。鄱阳湖水产养殖产生的养殖废水占其总污染量的比例较大,其对这类清水型湖泊水质的影响较大,对其富营养化的贡献率较高。建议清水型湖泊养殖的周边政府应控制蚌类的养殖规模,将蚌类养殖废水纳入废水处理的范围;蟹类养殖厂应对养殖水域的底泥进行处理,以免养殖废水对这类较清洁湖泊产生严重的污染。     

ICP-MS法测定高岭土中微量成分及杂质元素的研究

采用电感耦合等离子质谱技术,研究了高岭土中微量组分Fe₂O₃,TiO₂,K₂O,Na₂O,CaO,MgO及Pb,Cr,Mn,As,Cd,Cu等杂质元素含量的质谱分析方法。样品经HNO₃-HF低温溶解至清亮后, Si以四氟化硅的形式从溶液中挥发,消除了Si基体的干扰,继续加热至干, (1+3)HNO₃浸取。在线加入内标元素45Sc,115In,204Tl,采用内标法进行校正,有效克服了基体效应、接口效应及仪器波动所产生的影响,通过优化仪器工作参数,选择适当的待测元素的同位素,有效地克服了因质谱干扰所带来的影响。讨论了分析样品的制备过程中温度对砷元素测定的影响。该方法的加标回收率是95.0%～101.0%, 相对标准偏差(RSD)是1.1%～2.01%。对高岭土标准物质(编号GBW03122)进行了测定,测定结果与标准值相吻合。该方法具有快速、简便、准确等特点, 可用于高岭土及陶瓷产品中微量成分及杂质元素的含量分析。     

锐钛矿型TiO2(101)面原子几何及弛豫结构的第一性原理计算

采用平面波超软赝势方法计算了锐钛矿型TiO2(101)面的表面能和表面原子弛豫结构.首先对TiO2(101)面的6种不同的表面原子终止结构的体系总能量进行了计算,结果表明终止原子为两配位的O原子、次层为五配位的Ti原子的表面结构最为稳定.针对该表面研究了表面能和原子弛豫与模型中原子层数和真空厚度的关系,当原子层数为12层,真空厚度为0.4 nm时,表面能收敛度小于0.01 J/m2.研究发现:表面上两配位的O原子向里移动约0.0012 nm,五配位的Ti原子向里移动约0.0155 nm,弛豫后的Ti-O键长发生了较大变化,核外电荷发生了转移,结构趋于稳定.     

锐钛矿型TiO2(101)面原子几何及弛豫结构的第一性原理计算

采用平面波超软赝势方法计算了锐钛矿型TiO₂(101)面的表面能和表面原子弛豫结构.首先对TiO₂(101)面的6种不同的表面原子终止结构的体系总能量进行了计算,结果表明终止原子为两配位的O原子、次层为五配位的Ti原子的表面结构最为稳定.针对该表面研究了表面能和原子弛豫与模型中原子层数和真空厚度的关系,当原子层数为12层,真空厚度为0.4nm时,表面能收敛度小于0.01J/m².研究发现:表面上两配位的O原子向里移动约0.0012nm,五配 关键词： 第一性原理 2')" href="#">TiO₂ 表面结构 弛豫