基于功能核酸的水中汞离子荧光检测方法

二价汞离子作为一种重要的环境污染物，一直以来受到国内外广泛关注。基于T-T错配的Hg2+检测极大依赖于汞选择性寡聚核苷酸（MSO）的设计，利用SYBR Green I对目前所报道的汞离子探针进行了优化，研究了若干种MSO探针与Hg2+的结合响应，在对探针二级结构进行分析和讨论的基础上，提出最优的富T探针序列，并由此建立了一种基于SYBR Green I的水中汞离子快速、便捷的荧光检测方法。最终测得3种实际水样的加标回收率在82.8％~101.8％之间，相对标准偏差小于15%，表明该方法受环境基质的影响较小，可应用于实际水样中的汞离子检测。     

Syntheses of Divalent Rare Earth Ternary Halides KYbBr3, KYbCl3, KSm2Br5, KSm2Cl<5, KEu2Cl<5 by Alkalimetallothermoreduction

Introduction CsEuF_3, CsYbF_3 and RbYbF_3 are the first members of divalent rare earth ternary halides obtained via reduction of trivalent rare earth halides by alkali metals. Recently we adopted a new synthesis route in preparing divalent rare earth chlorides and bromides and the five titled compounds were suc-     

Microwave‐Sensitive Foamable Poly(ionic liquids) Bearing tert‐Butyl Ester Groups: Influence of Counterions on the Ester Pyrolysis

Several poly(ionic liquids) have been synthesized based on poly(1‐vinyl‐3‐tert‐butoxycarbonylmethylene imidazolium) salts with different counterions to investigate the tert‐butyl ester pyrolysis of these compounds. It is found that the counterions strongly influence the temperature of the pyrolysis. The pyrolysis temperature shifts to higher or lower temperatures depending on the nature of the counterions. The use of microwave irradiation was employed to accelerate the gas release because of the high dipolar interaction of amorphous salts with microwaves. The result of these reactions is the formation of organic foams that could be of industrial interest.

     

Photoluminescent behavior of SrB4O7:RE (RE=Sm and Eu) prepared by Pechini, combustion and ceramic methods

This work reports the preparation of system containing RE²⁺ ions (RE=Sm and Eu)-doped in SrB₄O₇ matrix by ceramic, Pechini and combustion methods. These compounds were prepared by reduction of RE³⁺ to RE²⁺ in air, which exhibit some different features according to the preparation method. Photoluminescent properties of these systems were investigated based on the emission and excitation spectral data. The emission spectra of SrB₄O₇:Eu²⁺ system prepared by combustion and Pechini methods are characterized by a broad band assigned to interconfigurational 4f⁶5d→4f⁷ transition, while SrB₄O₇:Sm²⁺ compound exhibit narrow emission bands arising from intraconfigurational-4f⁶ also shows ⁴G_5/2→⁶H_J′ transitions ( and ) arising from Sm³⁺ ion, transitions. SrB₄O₇:RE system prepared by combustion method presents emission bands from RE³⁺ ions as intense as that arising from RE²⁺, suggesting that the preparation route is not efficient for the reduction RE³⁺→RE²⁺ process. Emission quantum efficiency and radiative emission rates of Sm²⁺ ion are determined and discussed.     

A comparative study on structural,morphological and luminescence characteristics of Zn3(VO4)2 phosphor prepared via hydrothermal and citrate-gel combustion routes

Comparison of structural, morphological and spectroscopic properties of zinc vanadate Zn₃(VO₄)₂ phosphor synthesized via two different methods, viz. citrate-gel combustion and hydrothermal reaction, is presented. Highly crystalline and pure phase micro-rods are achieved by citrate-gel combustion route. The hydrothermal reaction products exhibit ribbon like structures. X-ray photoelectron spectroscopic investigation reveals the presence of multiple oxidation states of vanadium in the hydrothermally synthesized phosphor. Luminescence properties have also been compared and the effect of divalent cationic substitution (Ca, Mg) is presented.     

Anion Storage Chemistry of Organic Cathodes for High-Energy and High-Power Density Divalent Metal Batteries

Multivalent batteries show promising prospects for next-generation sustainable energy storage applications. Herein, we report a polytriphenylamine (PTPAn) composite cathode capable of highly reversible storage of tetrakis(hexafluoroisopropyloxy) borate [B(hfip)₄] anions in both Magnesium (Mg) and calcium (Ca) battery systems. Spectroscopic and computational studies reveal the redox reaction mechanism of the PTPAn cathode material. The Mg and Ca cells exhibit a cell voltage >3 V, a high-power density of ∼∼3000 W kg⁻¹ and a high-energy density of ∼∼300 Wh kg⁻¹, respectively. Moreover, the combination of the PTPAn cathode with a calcium-tin (Ca−Sn) alloy anode could enable a long battery-life of 3000 cycles with a capacity retention of 60 %. The anion storage chemistry associated with dual-ion electrochemical concept demonstrates a new feasible pathway towards high-performance divalent ion batteries.     

Conformational changes of strong polycations in the presence of divalent counterions and their influence upon the flocculation efficiency

The interaction between strong polycations, which possess the ammonium quaternary centers attached to an acrylic macromolecular chain derived from poly(N,N-dimethylaminoethyl methacrylate) (polycations Q_x), and divalent counterions was investigated by viscometry and turbidimetry. Conformational changes of polycations were influenced by the polycation charge density, counterion nature (SO₄²⁻ or S₂O₈²⁻) and concentration. The morphology of the polycation layers deposited onto silicon wafers has been studied by tapping mode atomic force microscopy, a strong influence of the polycation and ammonium persulfate concentration on the surface topography being observed. The optimum flocculation concentration of polycation decreased and the flocculation window increased in the presence of S₂O₈²⁻, in the destabilization of kaolin model dispersion. Removal of Congo Red from aqueous solution by the complex system formed between polycations and divalent counterions was also investigated. The behavior of polycations Q_x in separation processes was compared with that of one polycation containing 95 mol% N,N-dimethyl-2-hydroxypropyleneammonium chloride units in the backbone (PCA₅).     

Toluene disproportionation and coking on zeolites Y modified with Lewis-connected InO acid sites

The effect of introduction of Lewis acid sites on the reactions of toluene transformation and catalysts coking has been studied over parent (Si/Al = 2.5) and dealuminated (Si/Al = 3.7) Y zeolites modified with Lewis connected InO⁺ cationic acid sites. The catalysts with prevalent amount of Brönsted acid sites (less than 40% of protons exchanged by InO⁺) possess the typical for the proton directed reaction of methyl transfer upon toluene disproportionation long period of activation, the longer the higher the concentration of bridging protons. In contrast, at predominant Lewis sites concentration, the activation period disappear, an enhanced initial activity is observed, followed by deactivation on the expense of a rapid process of accumulation of strongly held reaction products and intermediates. Their further condensation leads to catalysts aging, the faster the higher the concentration of electron acceptor Lewis acid sites. A relation has been found between the initially accelerated processes of alkyl transfer and the reinforced formation of carbonaceous deposits over the In-modified catalysts.     

Effect of divalent cations on the volume of a maleic acid copolymer gel examined by incorporating lysozyme

An ionic gel of poly(maleic acid-alt-methyl vinyl ether) cross-linked by 1,6-hexanediol was prepared with molar ratio of 1/0.5 at 50 °C. The gels with different molar ratios at different temperatures were also prepared for comparison. Their swelling-shrinkage profiles were examined by measuring the ratio of initial to final weights at various pHs and CaCl₂ concentrations in buffer solution. The gel squeezed remarkably in the presence of Ca²⁺ for pH>6.3, corresponding to the solution properties of maleic acid copolymer. No appreciable change was observed below pH 6.3. To estimate free space in the gel in more detail, lysozyme was incorporated into the free space, and its release rate was measured under several CaCl₂ concentrations. The time course of the release was either simple or complicated, depending on pH and CaCl₂ concentration. The control mechanism of the release of lysozyme from the gel network may be widely applicable to the drug delivery system.