Computer simulation for effect of Tb3+ on Ca2+ speciation in human plasma

Effect of Tb3+ on Ca2+ speciation in human plasma was studied by means of the computer program of MINTEQA2. When Tb3+ ions are not added into the system, Ca2+ ions mostly distribute in free Ca2+ (74.7%) and the surplus distributes in Ca2+ complexes, such as [CaHCO3](+) (7.9%),[Ca(Lac)](+) (6.4%), CaHPO4 (1.3%), [CaHistidinateThreoninateH(3)](3+) (2.4%), [CaCitrateHistidinateH(2)] (2.3%) and CaCO3 (1.1%). Tb3+ can compete with Ca2+ for inorganic as well as biological ligands. An increase of concentration of Tb3+ in the system results in an increase of content of free Ca2+ and a decrease of contents of Ca2+ complexes.

Photochemical synthesis, properties and X-ray crystal structure of tetrabutylammonium dodecamolybdophosphate heteropoly blue

The title heteropoly blue, (Bu4N)(6)H-10 [(PMo11MoO40)-Mo-VI-O-V](4) . H2O has been photochemically synthesized and characterized with elemental analysis, solid diffusion reflectance electronic spectra, CV, ESR, XPS, IR spectra, conductivity measurement and X-ray single crystal analysis. The crystallographic data for C96H218Mo48N6O169P4 are as follows: M-r = 8889.76, triclinic, P (1) over bar, a = 1.4142 (3) nm, b = 2.6027 (5) nm, c = 2.6403(5) nm, alpha = 113.96(3)degrees, beta = 90.05(3)degrees, gamma = 105.71(3)degrees, V = 8.481 (3) nm(3), Z = 1, D-c = 1.741 g/cm(3), F (000) = 4264, mu = 1.798 mm(-1). The X-ray crystal structure analysis reveals that there Is one independent molecule in the unit cell of the title heteropoly blue which contains four mixed-valence heteropoly anions, six tetrabutylammonium cations and one water molecule. Its molecular structure possesses a centrosymmetrical arrangement in the unit cell. The phosphorus atom is In the crystallographic inversion center of the heteropoly anion and the eight oxygen atoms surrounding central phosphorus atom comprise of a distorted hexahedron. Heteropolyanion has two equal sets of PO4 tetrahedron. The PO4 tetrahedron and the MoO6 octahedron in the polyanion are greatly distorted.

Electrochemiluminescent determination of peroxydisulfate with Cr(bpy)(3)(3+) in purely aqueous solution

A novel method for the sensitive and selective determination of peroxydisulfate was proposed. It was based on an electrochemiluminescent method with Cr(bpy)(3)(3+). The applied potential was set at -0.5 V in Cr(bpy)(3)(3+) system which was much more positive than those in Ru(bpz)(3)(2+) and Ru(bpy)(3)(2+) systems. A linear calibration was obtained over the range of 7-100 mu mol l(-1) with a correlation coefficient of 0.993. The relative standard deviation was 2% for 10 replicate injections of 0.01 mol l(-1) S2O82- solution. The detection limit (S/N=3) was 1 mu mol l(-1). The method was successfully applied to determination of peroxydisulfate in phase transfer catalysis. (C) 2000 Elsevier Science B.V. All rights reserved.

Mild hydrothermal synthesis and optical properties of the complex fluoride KMgF3 doped with Eu

KMgF3 doped with Eu was synthesized by mild hydrothermal method at 240 degreesC for the first time. The excitation and emission spectra of the KMgF3 : Eu2+ phosphor were measured. Comparing with the sample synthesized through solid state reaction, the variation in the excitation spectra at 360 nm resulted from the existences of V-K color centers; the low emission intensity was due to Eu2+ having transferred part energy to V-K color centers.

掺Eu~(3+)、Tb~(3+)或Ce~(3+)的InBO_3的合成与光谱

采用固相反应法合成了InBO_3:Re(Re=Eu,Tb,Ce),研究了InBO_3基质中稀土离子的光谱特性,观察到电荷迁移带位于255 nm附近,Eu~(3+)离子在InBO_3 中产生极强的~5D_0→~7F_1 的跃迁表明Eu~(3+)离子在该基质中占据对称性格位。Tb~(3+)的4f-5d 允许跃迁位于240 nm附近,而4f-5d 禁戒跃迁位于267 nm附近,Tb~(3+)离子呈现出极强的~5D_4→~7F_5 发射。Ce~(3+)离子在InBO_3 中不发光。

用于高预倾角液晶显示器件新取向材料

研制一种新型的能够引起18°高预倾角的取向材料──聚酰亚胺（PI）YB29．探讨预倾角对固化温度、固化时间、摩擦强度的依赖关系；同时研究这种材料的红外吸收光谱、电子能谱及240°扭曲的液晶盒的电光特性.

Hydrothermal synthesis and lanthanide doping of complex fluorides, LiYF4, KYF4 and BaBeF4 under mild conditions

The complex fluorides LiYF4, KYF4, BaBeF4 and AYF(4)Eu(x) (A = Li, K) are hydrothermally synthesized at 140-240 degrees C and characterized by powder X-ray diffraction, thermogravimetric analysis, IR spectroscopy, scanning electron microscopy and luminescence measurements.

Lithium ion conducting polymer electrolytes based on alternating maleic anhydride copolymer with oligo-oxyethylene side chains

A comb polymer with oligo-oxyethylene side chains of the type -(CH2CB2O)(12)CH3 was prepared from methyl vinyl ether/maleic anhydride copolymer and poly (ethylene glycol) methyl ether. The polymer can dissolve LiClO4 salt to form homogeneous amorphous polymer electrolyte. The ac ion conduction was measured using the complex impedance method, and conductivities were investigated as functions of temperatures and salt concentration. The complexes were first found to have two classes of glass transition which increase with increasing salt content, The optimum conductivity attained at 25 degrees C is in the order of 5.50 x 10(-6)Scm(-1). IR spectroscopy was used to study the cation-polymer interaction.

Hydrothermal synthesis of the complex fluorides LiBaF3 and KMgF3 with perovskite structures under mild conditions

The complex fluorides, LiBaF3 and KMgF3; which are isostructural with perovskite phases, are hydrothermally synthesized at 120-240 degrees C and characterized by powder X-ray diffraction, thermogravimetric analysis, IR spectroscopy and scanning electron microscopy.

STM investigation of HOPG superperiodic features caused by electrochemical pretreatment

The surface topography of highly oriented pyrolytic graphite (HOPG) which has been subjected to anodized treatment at a low potential (less positive) has been exhaustively studied using scanning tunneling microscopy (STM). Characterization of graphite surface has revealed that a small percentage of the surface (5%-10%) shows superperiodic features. In this case, the typical topographical features are triangular networks with the observed periodicities in the plane ranging from approximately 26 to 240 nm with peak-to-peak amplitudes out of the plane extending from 7 to 35 Angstrom. We show that this triangular network can be attributed to the injection of electrolyte and solvent in the earliest stages of oxidation of the basal HOPG electrode surface. A simple model is proposed to explain this phenomenon.

THE IZOD IMPACT FRACTURE-BEHAVIOR OF PHENOLPHTHALEIN POLY(ETHER KETONE)

The Izod impact fracture behaviour of notched specimens of phenolphthalein poly(ether ketone) (PEK-C) has been studied over a temperature range from room temperature to 240 degrees C by using an instrumented impact tester. The temperature dependence of the maximum load, total impact energy, initiation energy, propagation energy, ductility index (DI) and the relationships between these parameters and the relaxation processes have been investigated.

CHOLESTEROL SENSOR-BASED ON ELECTRODEPOSITION OF CATALYTIC PALLADIUM PARTICLES

A layer of palladium particles was electrodeposited on a glassy carbon electrode. The dispersed Pd particles resulted in a large decrease in overvoltage for the electrochemical oxidation of H2O2 down to +0.4 V vs. Ag/AgCl, based on which a new kind of cholesterol sensor was fabricated. Cholesterol oxidase was immobilized on the Pd-dispersed electrode by cross-linking with glutaraldehyde and a layer of poly(o-phenylenediamine) (PPD) film was electropolymerized on the enzyme layer. The sensor shows a linear response in the concentration range 0.05-4.50 mmol l-1 with a rapid response of less than 20 s. The polymer film can prevent interference from uric acid and ascorbic acid and also increases the thermal stability of the sensor. The sensor can be used for 200 assays without an obvious decrease in activity.