Anderson结构铁钼杂多酸稀土盐的合成与结构表征

制备了具有Anderson结构的铁钼杂多酸稀土盐，经元素组成分析、TG和ICP确定其通式为Ln[FeMo6O24H6](Ln^3 =La，Ce，Pr，Nd，Sm，Gd，Dy，Yb)．采用IR，UV,^95Mo-NMR，XRD等方法进行了结构表征，发现在IR光谱图上呈现出羟基和H2O的两个振动谱带，并进行了归属，表明此类杂多酸稀土盐属Anderson结构B型．借鉴TG-DTA、不同温度下的IR和XRD及水溶性实验对Ln[FeMo6O24H6]和(NH4)3[FeMo6O24H6]的热解性质研究表明，此类杂多酸稀土盐的分解温度为350～400℃．比母体酸盐的热稳定性提高了10℃．     

咪喹莫特的波谱学数据与结构表征

对咪喹莫特的红外(IR)、紫外(UV)、质谱(MS)、氢-氢相关谱(^1H--^1H COSY)、碳氢相关谱(HMQC)、碳氢远程相关谱(HMBC)予以解析并进行了报道。对所有的^1H NMR、^13C NMR谱的信号进行了归属；讨论了质谱的主要碎片离子的可能的裂解方式和红外特征吸收峰所对应的官能团的振动形式。     

Determination of some reactive oxygen species scavengers based on the peroxidase-oxidase oscillator

This paper reports a new method for detection of ROS scavengers including superoxide dismutase, ascorbic acid and glutathione based on a 'probe' of peroxidase-oxidase biochemical oscillator. The oscillation period and amplitude change with different concentrations of scavengers. The linear ranges of superoxide dismutase, ascorbic acid and glutathione are respectively 1.56 x 10(-4)-1.56 x 10(-3) mg mL(-1), 1.75 x 10(-7)-1.75 x 10(-5) mol L(-1) and 9.38 x 10(-7)-7.5 x 10(-5) mol L(-1). The selectivity, linearity and precision for superoxide dismutase, ascorbic acid, and glutathione are presented and discussed. The results compared well with other standard methods for determination of superoxide dismutase, ascorbic acid and glutathione. Some possible steps in the overall reaction mechanisms are discussed.     

Formation of SnO2 Nanoparticles on External Surface of NaY Zeolite

Tin dioxide nanoparticles of 5 nm in size were prepared on NaY zeolite external surface by impregnation of SnCl2 solution and subsequent calcination at 623 K. A SnO2-NaY based chemical sensor for detecting H2 was demonstrated.     

Investigation on the Performance of Supported Molybdenum Carbide for the Partial Oxidation of Methane

The performance of uspported and unsupported molybdenum carbide for the partial oxidation of methane (POM) to syngas was investgated.An evaluation of the catalysts indicates that bulk molybdenum carbied has a higher methane conversion during the initial stage but a lower selectivity to CO and H2/CO ratio in the products.The rapid deactivation of the catalyst is also a significant problem.However,the supported molybdenum carbide catalyst shows a much higher methane conversion,increased selectivity and significantly improved catalytic stability.The characterization by XRD and BET specific area measurements depict an improved dispersion of molybdenum carbide when using alumina as a carrier.The bulk or the supported molybdenum carbide exists in the β-Mo2C phase,while it is transformed into molybdenum dioxide postcatalysis which is an improtant cause of molybdenum carbide deactivation.     

常见饮料中痕量铝的分光光度法研究

新试剂5-溴水杨基荧光酮可在pH5.5～6.8的六次甲基四胺缓冲溶液中,与铝,溴化十六烷基吡啶形成稳定的红色三元配合物。最大吸收波长约为568nm,摩尔吸光系数高达1.7×10~5L mol~(-1)·cm~1,常见金属离子很少干扰。据此,建立了测定微量铝的方法。其线性范围为0～6μg/25ml回收率在96％～103％之间。本文测定了常见饮茶,饮料及饮水中的微量铝。     

Possible Mechanisms of Intercalation

Recent knowledge of the kinetics and intercalation mechanisms are summarized and accompanied by examples of intercalation reactions of water and ethanol into anhydrous vanadyl phosphate and redox intercalation of alkali metal cations into vanadyl phosphate dihydrate. Three possible mechanisms of intercalation are presented which are based on: (i) a concept of exfoliation of layers; (ii) the formation of stages and randomly stacked layers; (iii) co-existence of intercalated and non-intercalated parts of crystals of the host separated by an advancing phase boundary. The corresponding kinetic curves are ascribed to mechanisms (ii) and (iii).     

Synthesis and electrochemical properties of spinel LiMn2O4 prepared by the rheological phase method

Pure-phase and well-crystallized spinel LiMn₂O₄ powders were successfully synthesized by a simple rheological phase method. The thermal behavior and structure properties of the powders prepared by the rheological phase method compared with the solid-state reaction were investigated by thermogravimetry, powder X-ray diffraction , scanning electron microscopy and transmission electron microscopy. According to the results of the electrochemical tests, it is obvious that the sample resulting from the rheological phase method shows higher discharge capacity and better cycling stability than one formed in the solid-state reaction. The cyclic voltammogram and columbic efficiency curves also confirm that the product by the rheological phase method has a good cycling performance due to its fine cubic spinel structure and morphology.     

Study of a molecular imprinting polymer coated BAW bio-mimic sensor and its application to the determination of caffeine in human serum and urine

A bio-mimic bulk acoustic wave (BAW) sensor was fabricated by coating the caffeine (CAF) template molecular imprinting polymer (MIP). This sensor exhibited high selectivity and a sensitive mass response to CAF. The response range of the sensor was between 5.0 x 10(-9) and 1.0 x 10(-4) M with a detection limit of 5.0 x 10(-9) M at pH 8.0. Recoveries were 96.1-105.6%. Influencing factors were investigated in detail and optimized. When employed to detect real samples, the proposed method proved to be a convenient method with the advantages of high sensitivity, good selectivity and ease of handling.     

Reduction and reconstruction of Co3O4 nanocubes upon carbon deposition

We describe a synthetic investigation on the formation of carbon nanofibers using a preshaped free-standing metal-oxide catalyst (single-crystal cobalt oxide (Co(3)O(4)) nanocubes). In reacting with acetylene (C(2)H(2)) vapor, Co(3)O(4) nanocubes are reduced and reconstructed into metallic cobalt. The resultant metal catalyst with a 2-fold symmetry leads to a bilateral base growth for carbon nanofibers. Our findings indicate that an understanding of catalyst-assisted chemical vapor deposition (CVD) mechanisms can be acquired, when the shape, size, and crystal orientation of pristine metal catalysts are made known to the CVD process. By tracing their evolutional changes in structure and composition, the shape-designed model catalysts may offer new opportunities for mechanistic investigations on the chemical reactivity of nanoparticles, general catalyst-assisted material synthesis, and metal intercalation chemistry.