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441.
442.
An all-solid-state polymeric membrane Pb2+ ion-selective electrode (Pb2+-ISE) based on bimodal pore C60 (BP-C60) as solid contact has been developed. A BP-C60 film can be readily formed on the surface of a glassy carbon electrode by electrochemical deposition. Cyclic voltammetry and electrochemical impedance spectroscopy have been employed to characterize the BP-C60 film. The large double layer capacitance and fast charge-transfer capability make BP-C60 favorable to be used as solid contact for developing all-solid-state ISEs. The all-solid-state BP-C60-based Pb2+-ISE shows a Nernstian response in the range from 1.0 × 10−9 to 1.0 × 10−3 M with a detection limit of 5.0 × 10−10 M. The membrane electrode not only displays an excellent potential stability with the absence of a water layer between the ion-selective membrane and the underlying BP-C60 solid contact, but also is insensitive to interferences from O2, CO2 and light. The proposed solid-contact Pb2+-ISE has been applied to determine Pb2+ in real water samples and the results agree well with those obtained by anodic stripping voltammetry. 相似文献
443.
The Effect of pH Values on the Synthesis,Microstructure and Photocatalytic Activity of Ce‐Bi2O3 by a Two‐Step Hydrothermal Method
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Fengjun Zhang Wei Lu Guosheng Xiao Zhuojing Liu Fanwei Xing Cong Lyu 《Photochemistry and photobiology》2015,91(5):1064-1070
In this study, the effect of pH values on the microstructure and photocatalytic activity of Ce‐Bi2O3 under visible light irradiation was investigated in detail. In alkaline condition (e.g. pH = 9), the as‐prepared Ce‐Bi2O3 exhibited an agglomerated status and mesoporous structures without a long‐range order. While in weak acid condition (e.g. pH = 5), the Ce‐Bi2O3 exhibited a best morphology with irregular nanosheets. Correspondingly, it possessed largest surface area (24.641 m2 g?1) and pore volume (9.825E‐02 cm3 g?1). These unique nanosheets can offer an attachment for pollutant molecules and reduce the distance of electron immigration from inner to surface, thus facilitating the separation of photoelectron and hole pairs. Compared with the pure Bi2O3, the band gap of Ce‐Bi2O3 prepared at different pH was much lower. Among them, the band gap of Ce‐Bi2O3 (pH of 5) was lowest (2.61 eV). Ce‐Bi2O3 (pH of 5) exhibited as tetragonal crystal with the bismuth oxide in the form of the composites, which could reduce the band gap width or suppress the charge‐carrier recombination, subsequently possessing great photocatalytic activity for acid orange II under visible light irradiation. After 2 h degradation under visible light, the degradation rate of acid Orange II was up to 96.44% by Ce‐Bi2O3 prepared at pH 5. Overall, it can be concluded that the pH values had effects on the microstructure and photocatalytic activity of Ce‐Bi2O3 catalysts. 相似文献
444.
CO2智能响应材料在受到CO2刺激时,材料自身物理结构或化学性质发生可逆转变.本文根据对CO2响应基团的不同,将CO2智能响应材料分成基于胺基基团和基于脒基基团的两大类,分别对其制备方法和应用进行了综述,并对CO2智能响应材料的发展进行了展望. 相似文献
445.
建立气相色谱–火焰光度法测定进口液化天然气中4种形态硫的方法。探讨了色谱柱、进样口温度、分流比、柱流速、升温程序和FPD检测器等对测定结果的影响。在优化的实验条件下,评价了方法的可靠性。4种形态硫化物的质量浓度在10.0~200.0μg/L范围内,其对数与峰面积对数呈良好的线性关系,线性相关系数r在0.983 3~0.999 2之间,检出限为1.7~7.7μg/L,测定结果的相对标准偏差为0.56%~0.68%(n=5)。用该法测定天然气形态硫标准气体,测定值与标准值相比,相对误差为–1.6%~–1.2%。该方法具有较高的准确度,可应用于进口天然气中4种形态硫的分析。 相似文献
446.
给出了多项式非线性系统的多维频率响应函数(MFRF)的解析表达式及其主要特性─—极点频率的定义和性质。对工程中多采用的三次多项式系统定义了广义传递函数,可在一维频率域中研究响应的谱结构。 相似文献
447.
可控约束阻尼层板的控制实验研究 总被引:5,自引:0,他引:5
对具有可控约束阻尼层的板进行了振动控制实验研究. 以压电片作为作动器,根据测量的结构振动信号,反馈控制约束层的变形,抑制板的振动. 对试验件进行了试验模态分析,讨论了压电片的附加位置;采用比例反馈对试验件进行了控制试验;试验给出了控制效果和压电片面积的关系. 研究结果证明,这种利用粘弹性阻尼抑制结构的高频振动,利用压电材料的逆压电效应控制结构的低频振动的主被动杂交控制方式对薄壁结构的振动抑制效果显著,控制频率范围宽,可靠性高. 相似文献
448.
论述了在地脉动对结构物的环境激励条件下,进行结构物地脉动响应测量的试验原理及方法,提出了固有频率识别与振型识别的互补较正法.通过对实际楼房结构的地脉动响应测量识别结构的模态参数.识别结果表明该理论及试验方法行之有效. 相似文献
449.
Proteome profiling was performed on Arabidopsis plant exposed to cold stress at 4 ℃ for 24 h in an attempt to explore the mechanisms of plant climate adaptation.The polyethylene glycol(PEG) fractionation protocol developed in this lab was used to identify as many differentially expressed low-abundance proteins as possible.In comparison with those of the biological controls,67 protein spots with at least two-fold difference in expression were identified for the plant exposed to cold temperatures; and from these spots,50 proteins were successfully identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS).Bioinformatics studies on these proteins show that 57.8% of these proteins were localized in the chloroplast.Of these proteins,8 ones have functions in photosynthesis,including glycine hydroxymethyltransferase,Rubisco large subunit,Rubisco activase,PSBO2,fructose-1,6-bisphosphate aldolase,NADP-dependent malate dehydrogenase,sedoheptulose bisphosphatase and photosystem Ⅱ reaction center PsbP family protein,suggesting that photosynthesis is greatly affected by cold stress.The identified proteins were validated by quantitative real-time polymerase chain reaction(qPCR).Taken together,our results suggest that the chloroplast might also act as a cold stress sensor and that photosynthesis-related proteins may play important roles in cold acclimation for Arabidopsis. 相似文献
450.
Si-Hong Zhou Qi-An Zhang Wei-Ran Lyu Cai-Dian Lü 《The European Physical Journal C - Particles and Fields》2017,77(2):125
We analyze charmless two-body non-leptonic B decays \(B \rightarrow PP, PV\) under the framework of a factorization-assisted topological-amplitude approach, where P(V) denotes a light pseudoscalar (vector) meson. Compared with the conventional flavor diagram approach, we consider the flavor SU(3) breaking effect assisted by a factorization hypothesis for topological diagram amplitudes of different decay modes, factorizing out the corresponding decay constants and form factors. The non-perturbative parameters of topology diagram magnitudes \(\chi \) and the strong phase \(\phi \) are universal; they can be extracted by \(\chi ^2\) fit from current abundant experimental data of charmless Bdecays. The number of free parameters and the \(\chi ^2\) per degree of freedom are both reduced compared with previous analyses. With these best fitted parameters, we predict branching fractions and CP asymmetry parameters of nearly 100 \(B_{u,d}\) and \(B_s\) decay modes. The long-standing \(\pi \pi \) and \(\pi K\)-CP puzzles are solved simultaneously. 相似文献