厌氧条件在不同Fe( II) 浓度测定方法中必要性的比较研究

厌氧是目前Fe(II)测定方法中常选择的处理方式,但是不可避免会给实验操作带来不便。为了方便、准确地测定铁还原体系中的Fe(II)浓度,对比研究了厌氧条件对草酸—草酸铵和盐酸两种典型浸提方法测定Fe(II)浓度的影响。结果表明:对于草酸—草酸铵浸提法,厌氧条件是必须的,以防止提取液中的Fe(II)被氧化,而且样品浸提1 h 便可用于Fe(II)的测定;然而对于盐酸浸提法,厌氧条件却并不是必须的,对Fe(II)浓度测定基本不产生影响。因此,为简化实验操作或在没有厌氧条件的情况,可利用盐酸浸提法测定铁还原体系中Fe(II)浓度

Diversity of archaea in the sediments from different areas of the Bohai Sea

Methanogens play an important role in the carbon cycle of coastal sediments. In this study, sea water enrichment cultures with acetate as the substrate were employed to enrich methanogens using sediments of the Bohai Sea. The methane production was used to estimate potential methane productivity and terminal restriction fragment length polymorphism analysis was used to analyze the diversity of microbial communities simultaneously. Our results revealed that changes in the bacterial and the methanogens community structures in sediments from different areas of the Bohai Sea were found. The dominant methanogens were Methanobacterium and Methanolobus in sediments of the Bohai Sea, and Desulfovibrio and Thiobacillus were the dominant bacteria. Different areas of the Bohai Sea obviously varied on methane production, which shows that the methane emission is higher in the coastal area. Bohai Sea has great potential for methane productivity and acetic acid conversion rate(46.46%), and the estimation of potential methane production is 1.74 Gt per year

基于共振隧穿二极管的集成电路研究

RTD基集成电路所具有的超高速、低功耗和自锁存的特性，使其在数字电路、混合信号电路以及光电子系统中有着重要的应用。首先对RTD与化合物半导体HEMT，HBT以及硅CMOS器件的集成工艺进行了介绍。在MOBILE电路及其进和延伸的基础上，对高速ADC/DAC电路和低功耗的存储器电路进行了具体的分析。最后对RTD基电路面临的主要问题和挑战进行了讨论，提出基于硅基RTD与线性阈值门(LTG)逻辑相结合是未来纳米级超大规模集成电路的最佳发展方向

Effects of water conditions on the diversity of soil microbial communities in the coastal reed wetlands

River-sea water interactions in coastal wetlands dramatically affect soil redox potential and cause variations in nutrient elements. In this study, we analyzed the changes in physicochemical properties of soil, diversity in the microbial community, and the Fe(III) reduction activity of microorganisms in reed wetlands of the Yellow River Delta under different water conditions. The results showed that the salinity, pH value, and concentrations of organic carbon, total nitrogen, and Fe(II) in the soil were higher in the flooded reed wetlands as compared with the ammonium concentration. The genera Alishewanella, Cellulomonas, Sphingomonas and Pseudomonas were the dominated bacteria in flooded reed wetlands, whereas Methanosarcina and Methanobacterium were the dominant archaea. Further, the dominated bacteria and archaea in the non-flooded reed wetlands were Cellulomonas, Acidovorax, Geobacter, Thiobacillus, and Methanosarcina, respectively. A shift in the iron-reducing bacterial community structure was also observed in the enrichment samples from flooded and non-flooded reed wetlands. Paracoccus, Geobacter, Alishewanella, and Thiomonas were the dominant iron-reducing bacteria in the flooded reed wetlands, and the dominant genera of iron-reducing bacteria in the non-flooded reed wetlands were Geobacter and Azospira. The diversity of soil bacteria, archaea, and iron-reducing bacteria was higher in the flooded reed wetlands. The Fe(III) reduction activity of iron-reducing bacteria in the reed wetlands was lessened to a certain extent by perennial flooded conditions

Potential direct interspecies electron transfer (DIET) from Clostridium spp. to Methanosarcina barkeri in amethanogenic isolation

【目的】革兰氏阴性菌Geobacter metallireducens可以与乙酸型产甲烷菌Methanosaeta harundinacea或Methanosarcina barkeri通过种间直接电子传递(DIET)还原CO2产甲烷。本实验室前期的研究发现Methanosarcina mazei和Geobacteraceae在铁还原富集培养中形成团聚体,可能存在直接电子传递。然而,革兰氏阳性菌(如Clostridium spp.)与产甲烷菌是否存在种间直接电子传递尚不明确。【方法】采用Hungate厌氧滚管法,以乙醇为唯一电子供体从铁还原富集培养体系中获得产甲烷分离物(S6)。通过T-RFL..

Potential direct interspecies electron transfer (DIET) from Clostridium spp. to Methanosarcina barkeri in methanogenic isolates

[Objective] Geobacter metallireducens, a Gram-negative bacterium, can directly transfer electron to acetoclastic methanogens such as Methanosaeta harundinacea and Methanosarcina barkeri for reducing carbon dioxide to methane. Our previous results showed that Methanosarcina mazei and Geobacteraceae formed aggregates in an iron(III)-reducing enrichment culture indicating direct interspecies electron transfer. However, the capability of direct electron transfer with methanogens for Gram-positive iron(III)-reducing bacteria such as Clostridium spp. is still unknown. [Methods] In this further study, methanogenic isolates(S6)were achieved from the iron(III)-reducing enrichment by roll-tube(Hungate)method with ethanol as the sole electron donor. We used terminal restriction fragment length polymorphism(T-RFLP)and clone library analysis to investigate the community of S6 and used electrochemical method such as cyclic voltammetry(CV)to confirm the electroactivity of isolates. [Results] Clone library analysis of 16S rRNA gene showed that Clostridium spp.(close to C. tunisiense)and Methanosarcina barkeri were predominant in the bacterial and archaeal community, respectively. Interestingly, addition of G. metallireducens into S6 did not increase the ability of both iron(III)reduction and methanogenesis, indicating that Clostridium spp. may play a similar role in direct interspecies electron transfer from G. metallireducens to M. barkeri. Furthermore, current generation of the S6 suspension dramatically decreased when contact between the organisms and the electrodes was prevented by dialysis bag, and CV showed no obvious redox peaks. [Conclusion] These results suggested that there was direct electron transfer in the methanogenic isolates. This work demonstrated that the dominant Gram-positive Clostridium spp. can potentially directly transfer electron to M. barkeri in methanogenic isolates

Effect of Temperature on the Self-Humidifying Open-Cathode Proton Exchange Membrane Fuel Cell

温度对自增湿阴极开放式质子交换膜燃料电池（PEMFC）的性能有着重要的影响. 依据自制的常压自增湿型PEMFC及温度控制设备搭建测试平台，测试了燃料电池在不同工作温度下的输出特性曲线—伏安曲线和功率输出曲线. 通过拟合得到了电极过程动力学参数，分析了工作温度影响电池性能的主要原因.Based on the experiments about the output characteristics of a home-made temperature-controlled PEMFC system with atmospheric pressure and no external humidifying condition in different loading voltages and operating temperatures, the optimum operating temperature at different loading voltages can be obtained by tracking the output characteristics of PEMFC operating over a range of temperatures. By analyzing the fitted data the kinetic parameters are evaluated and the effect of different operating temperatures on the PEMFC performance is discussed from a view of electrode kinetics.作者联系地址：1. 西南交通大学电气工程学院，四川 成都 610031；2. 西南交通大学机械工程学院，四川 成都 610031；3. 重庆理工大学机械工程学院，重庆 400054；4. 淡马锡理工学院清洁能源研究中心，新加坡 529757Author's Address: 1. School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China; 2. School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, China; 3. College of Mechanical Engineering, Chongqing University of Technology, Chongqing 400054, China; 4. Clean Energy Research Center, Temasek Polytechnic, 529757, Singapore通讯作者E-mail：[email protected]

The Relationship Between Ionic Conductivity and The Structure Of The New Polymer Electrolytes

新型导电高分子材料的导电性与其结构的关系梁洪泽，宋永贤，丁黎明，綦玉臣，李丽霞，景遐斌，王佛松（中国科学院长春应用化学研究所，长春，１３００２２）自Ｗｒｉｇｈｔ首次报道了聚环氧乙烷（ＰＥＯ）－碱金属盐（ＭＸ）配合物的离子导电性以来，有关各种聚合物固体...Ionic conductivity of polymer-eutectic composed of lithium perchlorate and lithium nitrate has been studied. The effects of eutectic and polymers upon the conductivities have been discussed.The lonic conductivity depends on the eutectic properties as well as the treatment method of samples.作者联系地址：中国科学院长春应用化学研究所Author's Address: Changchun Institute of Applied Chemistry,Chinese Academy of Science,130022 Changchu