A density functional study on magnetic exchange interaction between Mn(II) ion and nitronyl nitroxide radical in <Emphasis Type="Italic">trans</Emphasis>-and <Emphasis Type="Italic">cis</Emphasis>-metal-radical complexes

The magneto-structural correlation between a Mn(ll) ion, coordinated in an octahedral environment, and two nitronyl nitroxide radical ligands in trans- and cis-metal-radical complexes is investigated by the broken symmetry (BS) approach within density functional theory (DFT). The dependences of coupling constants J on three structural parameters: (i) bond angle θ (Mn-O-N (nitroxide)); (ii) rotating angle ψ, defined by the nitronyl nitroxide radical plane rotating around the axial Mn-O (nitroxide); (iii) bond distance R (Mn-O (nitroxide)) are directly calculated. Our calculations showed that both trans- and cis-Mn(ll)-radical complexes behave a stronger antiferromagnetic interaction, consistent with experiments. In view of molecular orbital theory, the direct exchanges, including σ-type and π-type exchanges, are responsible for the magnetic exchange pathways. There is a preferable linear correlation between the calculated coupling constants J and the overlap integral squares S b between the local magnetic orbitals at the various rotating angle ψ at the fixed bond angle θ and bond distance R, in both trans- and cis-Mn(ll)-radical complexes.     

带电胶体离子扩散与交换动力学的比较

Taking soil colloid and hydrated silica (quartz sand) as the experimental material, the comparative study has been made on the kinetics of ion diffusion and ion exchange in charged colloid and charged coarse disperse systems. The results showed that ion exchange kinetics in the two systems conform to the kinetic law of ion diffusion. Besides, through this comparative study on the kinetics of ion exchange and ion diffusion, a method has been advanced theoretically to estimate the quantity of adsorbed ion that is located in the inner of the Helmholtz layer. As far as hydrated silica is concerned , there were about 33 per cent of the total adsorbed quantity of Mg2+that were located in the inner of the Helmholtz layer under the given experimental conditions, bu tfor soil colloid the percentage was only 7.5.     

Optimizing Cs-exchange in titanosilicate with the mineral pharmacosiderite topology: framework substitution of Nb and Ge

Titanosilicates with complete or partial substitution of Ge or Nb in the framework and having the mineral pharmacosiderite topology were hydrothermally prepared and their ion-exchange properties towards Cs were studied for Ti/Ge/Si, Ti/Si, Nb/Ti/Si and pure Ge phases. The basis for the differences in the ion exchange properties measured as distribution coefficients (K_d) for these materials are detailed via structural characterization using the Rietveld refinement technique on the X-ray powder diffraction data. The differences in affinity towards Cs⁺ result either from the degree of hydration of the exchanger resulting in different coordination environments or the position of cesium ion in the eight-ring channel.     

Exchange reactions of copper complexes with amines

Square planar mixed ligand complexes of the type [CuLL′] where L = 5-chlorosalicylaldehyde and L′ = acetoacetanilide, have been synthesized on treatment with ammonia. Amine exchange of the above Schiff base complexes has been carried out on treatment with different amines. The reaction with ethanol amine is quite interesting compared to other amines. It reacts with 5-chlorosalicylaldehyde to form a Schiff base, while the β-diketone part is removed in the complex formation. All the complexes were characterized by elemental analysis, spectral studies, magnetic measurement, TLC, and conductane.     

Characterization of Carbohydrates in Paper and Paper Pulps Using Anion Exchange Chromatography and Principal Component Analysis

In the course of this investigation, a method for the characterization and differentiation of paper pulps was developed. After hydrolyzation of the papers and the respective raw pulps with trifluoroacetic acid, the hydrolyzates were analyzed with respect to their carbohydrate composition using ion exchange chromatography. The variations in carbohydrate composition mainly arise from the various hemicelluloses of the papers and pulps. The chromatographic results were then further processed using principal component analysis which allows correlating the various papers to different pulp materials.     

以交联聚乙烯醇为载体的离子交换剂对蛋白质的分离性能

本文对阴离子交换剂ＤＥＡ—ＰＶＴ常压液相离子交换色谱分离蛋白质的性能、分离条件进行了探讨。结果表明其对蛋白质的分离性能良好，容易洗脱。与载体交联聚乙烯醇相比，ＤＥＡ—ＰＶＴ对蛋白质的非特异性吸附明显降低。     

树脂法再生贮氢合金材料包覆液工艺中树脂吸附性能研究

本文研究并探讨了NK-ELN型离子交换树脂在再生贮氢合金材料包覆液过程中，温度、流速、溶液中离子浓度等条件对树脂交换容量和再生效率的影响，为树脂法再生贮氢合金材料包覆液工艺的制定，提供了一系列重要参数。     

The effect of the exchangeable metallic cation on the colloid properties of laponite treated with acridine orangea spectrophotometric study

The adsorption of the cationic dye acridine orange (AO) by different monoionic laponites leads to changes in the colloid properties of this synthetic mineral in aqueous solutions. The organic cation is adsorbed by the mechanism of cation exchange. Small amounts of adsorbed dye keep the clay in a peptized state with all metallic cations. Greater amounts of AO result in the neutralization of the electric charge of the clay, and its flocculation. In excess AO the charge of the clay platelets becomes positive and the clay is peptized. The colloid properties are studied by absorbance curves in which the absorbance is described as a function of the degree of saturation with constant clay concentrations or with constant dye concentrations. In the absorbance curves three regions can be identified. The transition between the first and second or the second and third regions depend on the exchangeable metallic cation initially present in the clay. The spectrophotometric method is useful in identifying the presence of tactoids and flocculation mechanism, whether it results in card-house or in book-house flocs.     

弱碱性阴离子交换树脂分离1,6—二磷酸果糖的研究

采用弱碱性阴离子交换树脂HJ-30对发酵液中1，6-二磷酸果糖的分离进行了研究。详细地研究了树脂的吸附和脱附性能。实验结果表明，HJ-30树脂对FDP的吸附量达0．28gFDP／g湿树脂，以0．05mol／LNaCl洗脱光机磷和1mol／LNaCl洗脱1，6-二磷酸果糖，产品的收率和纯度分别为92％和99．4％。     

Crystal chemistry and ion-exchange properties of the layered uranyl iodate K[UO2(IO3)3]

Single crystals of the potassium uranyl iodate, K[UO₂(IO₃)₃] (1), have been grown under mild hydrothermal conditions. The structure of 1 contains two-dimensional sheets extending in the [ab] plane that consist of approximately linear UO₂²⁺ cations bound by iodate anions to yield UO₇ pentagonal bipyramids. There are three crystallographically unique iodate anions, two of which bridge between uranyl cations to create sheets, and one that is monodentate and protrudes in between the layers in cavities. K⁺ cations form long ionic contacts with oxygen atoms from the layers forming an eight-coordinate distorted dodecahedral geometry. These cations join the sheets together. Ion-exchange reactions have been carried out that indicate the selective uptake of Cs⁺ over Na⁺ or K⁺ by 1. Crystallographic data (193 K, MoKα, ): 1, orthorhombic, Pbca, a=11.495(1) Å, b=7.2293(7) Å, c=25.394(2) Å, Z=8, R(F)=1.95% for 146 parameters with 2619 reflections with I>2σ(I).