Ba_2Pr_xLn_(1-x)Cu_3O_(7-δ)(Ln=Y,Nb,Yb,0≤X≤1)体系中Cu-O链及Cu-O层对超导作用的探讨

本文合成了 Ba_2P_(rx)Ln_(1-x)Cu_3O_(7-δ)系列化合物,测量了它们的超导电性(Tc),当 x=0.1,T_c(L_n=Y)=78.5K,T_c(Yd)=88K、T_c(Nd)<77K。晶胞参数及正交畸变与组成的变化图表明稀土元素的离子半径影响显著,讨论了 Ba_2LnCu_3O(7-δ)体系中 Cu-O 链、Cu-O 层及 Cu~(3+)对超导电性的作用,当 Ln 的价态界于三、四价之间时(如Pr),四价的成份越多,Cu~(3+)的量就越少,虽然正交畸变很大,但 T_c 降低。

在不同温度下Cu|CuSO_4|Hg_2SO_4-Hg电池标准电动势的确定

许多作者利用铜电极和汞-硫酸亚汞电极组成电池,研究硫酸铜的热力学性质,但该电池的标准电动势都是用扩展的Debye-Hükel公式外推得到的,由于Debye-Hükel公式中的离子大小参数无法实验直接测定,在选用时会给结果带来某些不确定性。本文测定了5～45℃间隔为10℃的电池。Cu|CuSO_4|Hg_2SO_4~-Hg (A)的电动势,在Pitzer电解质溶液理论基础上,提出了新的确定电池电动势的方法。

激光引发Cl_2和CH_2Cl_2对Cu的化学刻蚀

本文利用氩离子激光引发的化学反应,对铜片进行刻蚀研究,给出了刻蚀速率与激光能量和工作气体压强的关系曲线,得到 Cu—Cl_2体系的光刻能量阀值低于 Cu—CH_2Cl_2体系的结果并讨论了这一差别的原因。

Effect of heavy metals (Cd, Cu) on the gametophytes of Laminaria japonica Aresch

Effects of various concentrations of two heavy metals, namely Cd and Cu, on gametophytes of Laminaria japonica Aresch were determined by recording morphological changes of gametophytes, determining pH values and the heavy metal content of the culture solution, calculating the germination rate of sporophytes, and observing heavy metal (Cd) distribution using a fluorescence microscope. The results showed that heavy metals damaged the gametophytes, and were even lethal, and that the higher the concentration of heavy metal ions, the greater the injury to gametophytes. Gametophytes could not survive in culture solutions containing more than 100 mg/L Cd and 50 mg/L Cu and were only able to survive in culture solution containing a mixture of Cd and Cu tip to a concentration of 10 mg/L, which indicates that gametophytes have a higher tolerance to Cd than Cu and that multiple heavy metal ions in solution markedly aggravate the damage to gametophytes compared with individual heavy metal ions. With increases in the concentration of the heavy metal, the burgeoning rate of sporophytes decreased acutely, and solutions containing multiple heavy metal ions caused even more marked harm to sporophytes than solutions containing a single heavy metal ion, because most sporophytes died in mixed solutions. The pH value of the culture medium dropped immediately at the beginning (the first day) of treatment, increased over the following days, and then decreased again. The pH of culture media containing multiple heavy metal ions showed greater variation than media containing a single heavy metal ion, with the extent of the decrease in pH of culture media containing multiple ions being greatest during the last period of the experiment. With increases in the concentration of heavy metals, the capacity of gametophytes to accumulate these ions increased. The blue fluorescent light emitted by the Cd- and Cd-binding protein complex existing in gametophytes in media containing different concentrations of Cd showed clearly the distribution of the ion in gametophytes and the results obtained were consistent with distribution determined using other methods. All results of the present study showed that gametophytes of L. japonica play a remarkable role as heavy metal decontaminators, especially with regard to Cd.

The cDNA cloning and mRNA expression of cytoplasmic Cu, Zn superoxide dismutase (SOD) gene in scallop Chlamys farreri

Cu, Zn superoxide dismutases (SODs) are rnetalloenzymes that represent one important line of defence against reactive oxygen species (ROS). A cytoplasmic Cu. Zn SOD cDNA sequence was cloned from scallop Chlamys farreri by the homology-based cloning technique. The full-length cDNA of scallop cytoplasmic Cu, Zn SOD (designated CfSOD) was 1022 bp with a 459 bp open reading frame encoding a polypeptide of 153 amino acids. The predicted amino acid sequence of CfSOD shared high identity with cytoplasmic Cu. Zn SOD in molluscs, insects, mammals and other animals, such as cytoplasmic Cu, Zn SOD in oyster Crassostrea sostrea gigas (CAD42722), mosquito Aedes aegypti (ABF18094), and cow Bos taurus (XP_584414). A quantitative reverse transcriptase real-time PCR (qRT-PCR) assay was developed to assess the mRNA expression of CfSOD in different tissues and the temporal expression of CfSOD in scallop challenged with Listonella anguillarum, Micrococcus luteus and Candida lipolytica respectively. Higher-level mRNA expression of CfSOD was detected in the tissues of haemocytes, gill filaments and kidney. The expression of CfSOD dropped in the first 8-16 h and then recovered after challenge with L. anguillarum and M. litteus, but no change was induced by the C. lipolytica challenge. The results indicated that CfSOD was a constitutive and inducible acute-phase protein, and could play an important role in the immune responses against L. anguillarum and M. luteus infection. (C) 2007 Elsevier Ltd. All rights reserved.

Sorption and desorption of Cu and Cd by macroalgae and microalgae

The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment. (C) 1998 Elsevier Science Ltd. All rights reserved.

Theoretical study of interaction between atoms of Au, Ag, Cu and clean Si(111) surface

To evaluate the interactions between the atoms of An, Ag and Cu and clean Si(111) surface, two types of silicon clusters Si4H7 and Si16H20 together with their metal complexes were studied by using hybrid (U)B3LYP density functional theory method. Optimized geometries and energies on different adsorption sites indicate that: (1) the binding energies at different adsorption sites are large (ranging from similar to 1.2 to 2.6 eV depend on the metal atoms and adsorption sites), suggesting a strong interaction between metal atom and silicon surface; (2) the most favorable adsorption site is the on top (T) site. Mulliken population analysis indicated that in the system of on top (T) site, a covalent bond is formed between metal atom and dangling bond of surface Si atom. (c) 2006 Elsevier B.V. All rights reserved.

硫酸盐还原菌混合菌群胞外聚合物对Cu^2＋的吸附和机理

生物吸附法是处理含重金属废水的一种新兴的处理技术。微生物所分泌的胞外聚合物（EPS）在微生物吸附重金属中起重要作用。硫酸盐还原菌（SRB）混合菌群分泌的EPS能有效的吸附水溶液中的Cu^2＋，Langmuir等温方程和Freundlich等温方程都能拟合实验所得吸附数据，最大吸附容量达到478．47mg／gEPS。水溶液的初始pH值对EPS吸附Cu^2＋影响明显，在pH为7时，吸附效率最高，pH增减，吸附效率明显下降。SRB混合茵群分泌的EPS的FT—IR分析表明，EPS对Cu^2＋的吸附主要在于EPS中的蛋白质的酰胺（Ⅱ）、羧基、多聚糖的C-O-C、OH和脂类等基团对Cu^2＋的强络合能力.

EDTA对狭叶香蒲吸收水中Cu^2＋及Cu^2＋在组织中迁移的影响

水培实验研究表明，100mg／L的Cu^2＋和0．5mmol／L的EDTA对狭叶香蒲（Typha angustifolia L．）的生长起到抑制作用。同时0．5mmol／L的EDTA能够促进狭叶香蒲吸收水中的Cu^2＋，并促进Cu^2＋从须根向地上部分转移，茎和叶中积累的Cu^2＋浓度为1233．8mg／kg和632．3mg／kgDW（干重），Cu^2＋从须根转移到茎部分的转移系教TFs从0．95上升到2．15；从须根转移到叶部分的转移系教从0．48上升到1．10.