微波场中甲烷部分氧化制合成气 Ⅱ.Co/ZrO_2催化剂在微波场中的升温行为及催化活性

近年来，甲烷部分氧化制合成气（ＰＯＭ）的研究一直十分活跃［１，２］．前文报道了用于甲烷部分氧化制合成气的镍基催化剂（Ｎｉ／Ｌａ２Ｏ３）在微波场中的升温行为和催化活性［３］，发现在达到相同的ＣＨ４转化率时，微波活化方式下的催化剂床层温度比常规加热低得多...     

The systems Zr(Nb,Ti)(R)O2−δ, R=Yb, Ca—optimization of mixed conductivity and comparison with results of other systems (R=Y and Gd)

In this work we address the optimization of mixed conductivity in fluorite compounds based on zirconia. Phase relations of the new systems YbO_1.5-NbO_2.5-ZrO₂, and CaO-NbO_2.5-ZrO₂ are presented. The limit of the cubic defect fluorite phase in YbO_1.5-NbO_2.5-ZrO₂ closely resembles that of the system YO_1.5-NbO_2.5-ZrO₂, whilst in CaO-NbO_2.5-ZrO₂ is narrow extending to include composition Ca_0.255Nb_0.15Zr_0.595O_1.82 at 1500°C. The influence of dopant ion size, charge and composition on ionic conduction is assessed and parallels are drawn with the systems YO_1.5-NbO_2.5-ZrO₂ and YO_1.5-TiO₂-ZrO₂. Comparison of these results with published data on the Ti containing systems CaO-TiO₂-ZrO₂, GdO_1.5-TiO₂-ZrO₂ shows that the highest mixed conducting compositions can only be offered in the system YO_1.5-TiO₂-ZrO₂ out of all the systems here studied.     

Study on interaction between drug and membrane by using liposome coated zirconia-magnesia chromatography

The interactions between drug molecules and membrane were studied using the new chromatography stationary phase of liposome coated zirconia–magnesia. log K_s(ZrO₂–MgO) on this new chromatography for some drugs, compared with that on liposome coated silica chromatography and other reported data, fair correlations were observed between them when excluding effect of special adsorption. log K_s(ZrO₂–MgO) values for barbitalum, diazepam, benzene, benzocaine and toluene correlated well with corresponding values on liposome coated silica chromatography (R = 0.99778, P < 0.001; R = 0.98229, P < 0.003; R = 0.9985, P < 0.0001; R = 0.99925, P < 0.0001, pH value of mobile phase at pH 7.4, 7.0, 6.4 and 5.4, respectively). They also correlated well with the literature data on immobilized artificial membrane chromatography (R = 0.99999, P < 0.004 at pH 7.4) and liposome chromatography (R = 0.99994, P < 0.008) for procaine, lidocaine and bupivacaine. Liposome coated zirconia–magnesia chromatography can thus be used for studying drug–membrane interaction and prediction of drug absorption as another liposome chromatography method.     

Electrochemistry of vanadium-doped tetragonal and monoclinic ZrO2 attached to graphite/polyester composite electrodes

The electrochemistry of monoclinic and tetragonal vanadium-doped zirconias (VZrO₂), prepared from gel precursors with vanadium loadings ranging from 0.5 to 15 mol%, has been studied using abrasive-conditioned graphite/polyester composite electrodes immersed in aqueous HCl and HClO₄ solutions. Isolated vanadium centers form a solid solution in the zirconia lattice with a solubility limit close to 5 mol%. Above 5 mol%, finely dispersed V₂O₅ is formed. Vanadium centers located at the boundary sites of the zirconia lattice display successive one-electron transfer processes near to +0.25 and +0.10 V vs. SCE, whereas finely dispersed V₂O₅ yields three successive reduction processes at +0.46, +0.30, and +0.16 V vs. SCE. Electrochemical data indicate the presence of both V⁵⁺ and V⁴⁺ centers in the lattice of monoclinic and tetragonal zirconias, the V⁵⁺/V⁴⁺ ratio decreasing as the vanadium loading increases. Electronic Publication     

碳十八键合锆胶固定相的制备与色谱性能评价

用诱导聚合胶体凝聚法（PICA）制得的二氧化锆微球与碳十八三乙氧基硅烷反应制备了碳十八键合锆胶固定相（ODZ），评价了该柱填料的色谱性能，并用此固定相分离了中性和碱性化合物。     

Regioselective side-chain as well as nuclear monobromination of aromatic substrates with N-bromosuccinimide using phosphotungstic acid supported on zirconia as a heterogeneous catalyst

Regioselective monobromination of aromatic substrates with N-bromosuccinimide has been achieved in excellent isolated yields (84–98%) using phosphotungstic acid supported on zirconia as a novel heterogeneous catalyst. The catalyst has been characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area and acidity measurements. Remarkably, the new catalyst system described brought about the side-chain bromination of aromatics to afford bromomethyl arenes in excellent yields (86–98%) without the need for a radical initiator. Recovery and recylability of the catalyst have been well established.     

不同分子筛载体对CO加氢产物分布的影响

研究了几种小孔分子筛ＺＳＭ－５，ＨＹ，ＮａＹ及β担载ＺｒＯ２对Ｃ加氢反应的催化作用，并就产物的分布情况与担载ＺｒＯ２的硅铝中孔分子筛进行了对比研究。其中中孔分子筛分别用季铵盐和一级胺为模板剂，在水热条件和常温常压下合成；并用ＢＥＴ，ＸＲＤ，ＳＥＭ等手段表征了它们的孔道和骨架结构。另外，考察了碱金属Ｋ＾２＋，Ｎａ＾２＋对催化剂催化性能的影响。     

染料配体脲醛树脂-二氧化锆复合微球的制备及对牛血清白蛋白的萃取性能

采用溶胶-凝胶法制备无孔脲醛树脂-二氧化锆复合微球,在碳酸盐缓冲溶液中,利用微球表面的酰胺键与三嗪染料-活性艳蓝X-BR分子中三嗪环上的活泼氯反应,将染料键合到微球表面,以牛血清白蛋白(BSA)为样品,考察了不同条件下,该萃取剂对BSA的萃取能力。结果表明,该萃取剂对BSA的饱和萃取量达到30.3 mg.g-1,同时萃取的蛋白易于洗脱,1.0 mol.L-1氰化钾的洗脱率达到93.5%。     

Diffuse scattering. X-rays vs. neutrons

Fundamental and experimental differences between X-ray and neutron scattering methods are outlined and the advantages of either radiation for the study of disorder in crystals are described. Special emphasis is laid on their complementarity, e.g. to identify the atomic species involved in the disorder or to decide between the elastic or inelastic nature of the diffuse scattering (static or dynamic disorder). This is illustrated by three examples: LiNbO₃ (dynamic nature of chain-like disorder), doped Zr0₂ (identification of cationic and anionic disorder components) and decagonal quasicrystals (distinction between quasi-isoelectronic elements).     

Facile Fabrication of Zirconia Modified Screen‐Printed Carbon Electrodes for Electrochemical Sensing of Phosphate

We report here a facile method to immobilize zirconia nanoparticles on a disposable screen‐printed carbon electrode (designated as ZrO₂‐SPCE) for phosphate sensor application. Simply by ultrasonicating a bare SPCE in a ZrO₂ slurry, ZrO₂ nanoparticles can be immobilized effectively on the electrode surface as verified by surface characterization evidences. Using ferricyanide as a redox probe, an increase in the charge transfer resistance (R_ct) of ferricyanide upon adsorption of phosphate on ZrO₂ is used for the determination of phosphate. This ZrO₂‐SPCE phosphate sensor shows a wide linear range up to 1 mM and a detection limit of 1.69 µM (S/N=3). Practical applicability of the ZrO₂‐SPCE is demonstrated by detecting phosphate content in human blood samples.