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101.
102.
Chengzhi Hu Huijuan Liu Jiuhui Qu 《Colloids and surfaces. A, Physicochemical and engineering aspects》2005,260(1-3):109-117
This paper introduces a new electrochemical method for preparation of polyaluminum chloride (PACl) which contains high content of Al13 and active chlorine and presents integrated properties of flocculation with oxidation. E-PACl (PACl prepared by electrolysis process) samples were successfully prepared in an electrochemical reactor, which used Ti/RuO2–TiO2 anodes and Ti cathodes. Anode potential was the key electrochemical parameter that needed to be controlled at 1.5 V to ensure the maximal current efficiency of main reactions in electrolysis process. Analyses by ferron colorimetric method and 27Al NMR spectroscopy indicated that Al13 was the predominant species in the final product when total Al concentration (AlT) was in the range of 0.1–1.5 mol/L. The amount of active chlorine was in inverse proportion to AlT. Contents of the most active component, Al13 and active chlorine could respectively reach 90.9% and 5650 mg/L with AlT = 0.51 mol/L and basicity (B, OH/Al molar ratios) = 2.23 in the liquid product of PACl (E-PACl2). In E-PACl2, the sulfate precipitate of Al13 was the unique material detected by X-ray diffraction patterns and clusters of small spheres that might be the aggregates of Al13 were observed on the surface of its air-dried sample by atomic force microscopy. Results of dynamic light scattering showed that the particle size distributions of E-PACl were related with the Al species distributions and ageing time. The active chlorine in E-PACl2 performed well on disinfection of raw water. 相似文献
103.
Acrylamide and aromatic aldehydes were found to undergo the Baylis-Hillman reaction at ambient temperature in an aqueous medium in the presence of a stoichiometric amount of base catalyst, DABCO, to give the corresponding 3-hydroxy-2-methylenepropionamides in 61-99% yield. A faster competing, but reversible, non-Baylis-Hillman reaction was initially observed under the conditions to form N-acylhemiaminals, which later disappeared, as the desired Baylis-Hillman adduct was formed as the major product over an extended period of time (12-48 h). This represents the first demonstration of the Baylis-Hillman reaction of aldehydes with acrylamides, which were thought to be inert under atmospheric pressure and at ambient temperature. 相似文献
104.
铝离子与脱氧核糖核酸作用的共振光散射研究 总被引:20,自引:0,他引:20
在PH2.21的酸性介质中,Al^3 与脱氧核糖核酸(DNA)发生静电作用产生以291.0nm为特征峰的共振光散射(RLS)增强光谱,即Al^3 主要与DNA分子表面的磷酸根结合,但DNA热变性将导致Al^3 与DNA的碱基结合,使光散射信号降低,在291.0nm处的共振光散射(RLS)强度与DNA的浓度呈线性关系,据此建立了用共振光散射测量痕量DNA的新方法,方法的检出限为ng级,用于合成样分析,回收率在91.6%-105.0%。 相似文献
105.
Assembling and ordering nanomaterials into desirable patterns are considerably significant, since the properties of nanomaterials depend not only on the size and shape, but also on the spatial arrangement among the collective building blocks. In this work, the DNA self-assembly technology of hybridization chain reaction (HCR) provided a convenient method to yield long double-strand DNA (dsDNA) to install gold nanoparticles (AuNPs) into one dimensional assembly along the skeleton of dsDNA. Interestingly, the tunable length of AuNPs assemblies along dsDNA chain could be achieved by adjusting the reaction time of HCR, which is based on the formation of covalent bond between Au and the -SH group of DNA. Compared with weak light scattering of single AuNP, these AuNPs assemblies could be clearly imaged under the dark field microscopy, indicating that the light scattering was greatly improved after assembling. 相似文献
106.
Estimating gas holdup via pressure difference measurements is a simple and low-cost non-invasive technique to study gas holdup in bubble columns. It is usually used in a manner where the wall shear stress effect is neglected, termed Method II in this paper. In cocurrent bubble columns, when the liquid velocity is high or the fluid is highly viscous, wall shear stress may be significant and Method II may result in substantial error. Directly including the wall shear stress term in the determination of gas holdup (Method I) requires knowledge of two-phase wall shear stress models and usually requires the solution of non-linear equations. A new gas holdup estimation method (Method III) via differential pressure measurements for cocurrent bubble columns is proposed in this paper. This method considers the wall shear stress influences on gas holdup values without calculating the wall shear stress. A detailed analysis shows that Method III always results in a smaller gas holdup error than Method II, and in many cases, the error is significantly smaller than that of Method II. The applicability of Method III in measuring gas holdup in a cocurrent air–water–fiber bubble column is examined. Analysis based on experimental data shows that with Method III, accurate gas holdup measurements can be obtained, while measurement error is significant when Method II is used for some operational conditions. 相似文献
107.
A novel three-phase composite of Co/CoO/Co3O4 is synthesized through straightforward calcination treatment towards cobalt-based metal-organic gel (Co MOG) precursor, which is constructed with the metal source of cobalt chloride and organic ligand of 4, 4', 4”-((1, 3, 5-triazine-2, 4, 6-triyl) tris (azanediyl)) tribenzoic acid at room temperature. The morphology, structure and composition of the derived Co/CoO/Co3O4 is confirmed through scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and X-ray photoelectron spectrums (XPS). Furthermore, the composite of Co/CoO/Co3O4 is employed as electrode modified material with the excellent electrochemical performances of accelerating the electron transfer and boosting the electrode interface reaction. As a proof of concept, the electrochemical redox behaviors of diethylstilbestrol (DES) have been systemically investigated at the modified electrode interface and the established analytical approach for DES with the broad linear range and satisfied recovery. This work not only provided a facile approach to obtain electrode material with excellent electrochemical performance but also enriched the application of MOG materials in the electrochemical field. 相似文献
108.
毛细流自组装成环荧光显微测定血清样品中硫酸奎尼丁 总被引:1,自引:1,他引:1
在0.01 mol/L H2SO4的介质中,有聚乙烯醇-124存在时,硫酸奎尼丁(QDS)溶液通过毛细流作用能在憎水性玻璃表面上自组装成环(SOR)。环的最大荧光强度与硫酸奎尼丁的量成正比,据此建立了一种显微荧光自组装成环技术测定血清硫酸奎尼丁的新方法,测定硫酸奎尼丁的线性范围为(0.2~1.4)×10-12mol;检出限(3σ)为2.6×10-14mol。本方法已成功用于血清中硫酸奎尼丁的测定,回收率为93.3%~101.3%。 相似文献
109.
氯化钠介质中小牛胸腺脱氧核糖核酸对铈(Ⅲ)的荧光猝灭机理 总被引:9,自引:0,他引:9
在PH〈6.2的NaCl介质中,Ce(Ⅲ)受254.0nm紫外光激发所产生的350.0nm荧光因Ce(Ⅲ)的各种阳离子型体与小胸腺DNA上的磷酸根发生静电作用而被猝灭。 相似文献
110.
Zhang Xiaofang Wang Baoguang JIANG Chengzhi He Shunzhong CHEN Lincai Zhang Xiaoyuan 《中国光学快报(英文版)》2001,(2)
In this paper, a new reference optical system is put forward to achieve longitudinal displacement measurement. An optical grating is used for frequency mixing and getting high SNR signals in the measurement. Conditions and methods for getting Doppler beat signals are presented.The experiments indicate that this optical syetem can be used to measure the longitudinal displacement with high accuracy. 相似文献