Biosorption mechanism of Cr (Ⅵ) onto cells of Synechococcus sp.

The biosorption mechanism of Cr (Ⅵ) ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr (Ⅵ) consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-IR spectra of K_2Cr_2O_7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp. show that the speciation of chromium that binds to the cells of Synechococcus sp. is Cr (Ⅲ), instead of Cr (Ⅵ), and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr (Ⅲ). Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr (Ⅵ), and the results of FT-IR show that the biosorption of Cr (Ⅵ) follows two subsequent steps, biosorption of Cr_2O_(7~)2-))by electrostatical force at the protonated active sites and reduction of Cr_2O_(7~(2-)) to Cr3+ by the reductive groups on the surface of the biosorbents.     

脉冲布袋除尘器的控制技术

采用可编程控制除尘设备运行，具有结构紧凑，功能完备，可靠性高，操作简便，维护简单等特点，控制内容包括清灰，卸灰，输灰及排灰，并要求设备进行单动和联动运转的控制。     

电力变压器制造监理中的常见问题处理

变压器是电力系统中的重要设备,其产品质量直接决定着电力系统能否安全可靠运行,因此对变压器制造过程进行设备监理是非常必要的。对220 k V电力变压器制造监理中的一些关键点进行了分析,并说明了常见问题的处理对策,有效预防了一些制造缺陷,提高了变压器的制造质量,为电力系统的安全稳定运行提供了可靠保障。     

可调移液器的容量检定

介绍了移液器的检定方法,分析了检定过程中的注意事项,提出相应的解决措施,希望为今后移液器的检定工作提供借鉴。     

某低品位硫化铜矿混合菌浸出研究

利用混合菌对低品位硫化铜矿进行槽浸研究,并通过实时荧光定量PCR（RT-PCR）技术监测浸出过程中菌群的动态变化。研究结果表明,多种浸矿菌共同作用20 d,硫化铜矿中铜的生物浸出率达到85.66%,而酸浸仅为24.43%。在生物浸出的2～12 d,At.ferrooxidans是主要的浸矿菌,浸出液中Fe²⁺浓度快速下降、Eh上升,促进硫化矿的快速分解,Cu的浸出率达到79.50%;12 d以后,混合菌中的优势种逐渐被At.thiooxidans取代,浸出速度逐渐降低。此外,Mantel test结果表明,浸出液中Cu和Fe与微生物群落结构显著相关。     

传统文化与高职学生人文素质教育

传统文化蕴含丰富的人文底蕴,可应用于学生人文素养的培养活动中。高职语文课程包含大量的传统文化素材,以该课程为载体,通过整合教材内容,改进教学方法,更新评价方式,让学生关心社会,关注生活,提高人文素养。     

基于"劳力上劳心"的高等职业教育改革

近年来,我国的高等职业教育发展迅速,对社会和地方经济发展起到了一定的促进作用,但由于缺乏办学经验,职业教育在内涵建设方面还存在许多问题.从叶圣陶的"劳力上劳心"教育观点出发,认为高等职业教育应紧紧围绕"劳力"这一环节进行改革,大力加强学生的实践动手能力培养.     

水溶液中毒死蜱在紫外激发下的快速降解

实验以400w高压汞灯（主波长：365nm） 光源，降解水中毒死蜱，不同时间取样，样品的一部分革取，并用GC—ECD检测毒死蜱的残留量，结果表明，毒死蜱在90min内的降解率为94％，反应符合零级反应动力学，半衷期为15．2min。样品的另一部分直接进行液质分析，检测到了系列的中间产物，提出了可能的降解机理。     

Preparation, optical properties and cell staining of water soluble amine-terminated PAMAM G2.0-Au nanocomposites

The solution chemical and optical characteristics of formation of amine-terminated polyamidoamine dendrimer G2.0（NH2-PAMAM G2.0）-Au nanocomposites in the aqueous solution of NH2-PAMAM G2.0 at various mole ratios of Au（Ⅲ） to NH2-PAMAM G2.0 were studied by both UV-visible spectrometry and fluorospectrometry. The NH2-PAMAM G2.0-Au nanocomposites, with a type of structure in which one Au nanoparticle is surrounded by several NH2-PAMAM G2.0 dendrimers, emit strong bluish violet fluorescence, and are uniform, water soluble and biocompatible as well as very stable in frozen conditions. The size of gold nanoparticles in the nanocomposites is about 2.5 nm and decreases with the increase of NH2-PAMAM G2.0 concentration. The NH2-PAMAM G2. 0 plays an important role in acting as host or micro-reactor for Au（Ⅲ） before Au（Ⅲ） reduction and acting as dispersant and stabilizer for gold nanoparticles after Au（Ⅲ） reduction. Preliminary experiments of cells staining to human embryonic lung fibroblast cell lines show that the NH2-PAMAM G2.0-Au nanocomposites can be used as optical imaging markers for bioanalyses and medical diagnoses.     

Biosorption mechanism of Cr （Ⅳ） onto cells of Synechococcus sp.

The biosorption mechanism of Cr （Ⅳ） ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr （Ⅳ） consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-LR spectra of K2Cr2O7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp show that the speciation of chromium that binds to the cells ofSynechococcus sp. is Cr （Ⅲ）, instead of Cr （Ⅳ）, and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr （Ⅲ）. Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr （Ⅵ）, and the results of FT-IR show that the biosorption of Cr （Ⅵ） follows two subsequent steps, biosorption of Cr2O7 ^2- by electrostatical force at the protonated active sites and reduction of Cr2O7^2- to Cr^3＋ by the reductive groups on the surface of the biosorbents.