新显色剂噻二唑偶氮二甲氨基苯甲酸与铜(Ⅱ)显色反应的研究和应用

本文研究了噻二唑偶氮二甲氨基苯甲酸与Cu(Ⅱ)显色反应条件,确定在pH3.0～4.5范围形成蓝紫色络合物,组成比为1:1,摩尔吸光系数ε=4.55×10~4L·mol~(-1)·cm~(-1),1gβ=7.32。应用拟定的方法测定天然水中微量铜,获得满意的结果。     

Catalytic Combustion of Methane over CO1-xMgxO/Al2O3/FeCrAl Monolithic Catalysts

A series of CoxMgxO/Al2O3/FeCrAl catalysts （x=0-1） were prepared. The structures of the catalysts were characterized using XRD, SEM, and TPR analyses. The catalytic activity of the catalysts for methane combustion was evaluated in a continuous flow microreactor. The results indicated that the active washcoats adhered well on the FeCrAl foils. The phases in the catalysts were Co--xMgxO solid solutions, α-Al2O3, and γ-Al2O3. The surface particle size of the catalysts varied with variations in the molar ratios of Co to Mg. The Co component of the Co1_xMgxO/Al2O3/FeCrAl catalysts played an important role in the catalytic activity for methane combustion. In the Co1-xMgxO/AluO3/FeCrAl series catalyst （x=0.2-0.8）, the catalytic activity in terms of x was in the order of 0.5〉0.2〉0.8 under the experimental conditions. The presence of Mg in these catalysts could promote the thermal stability to a large extent. There were strong interactions between the Co1-xMgxO oxides and the AluO3/FeCrAl supports.     

电渗流与缓冲液浓度之间数学关系的线性表达

It was believed that electroosmotic mobility μeo is inversely proportional to the square root of the ionic strength L But the linear relationship for regression analysis was expressed differently in different papers. The paper studied the linear expression of the mathematical relationship between μeo and c （background buffer concentration） by mathematical transform and real experimental data.μeo values of fused silica capillary were determined in four buffer systems. Their experimental conditions were controlled carefully for decreasing temperature difference AT and pH difference ApH in 50 μm ID capillary, in which no double layer overlap existed. The linear relationship between the reciprocal of electroosmotic mobility and the square root of concentration （or ionic strength） was derived by mathematical method. The regression analysis of experimental data was shown to well correspond to the relationship. The constants in regression equation could be well defined and the calculated results were acceptable.     

Synthesis and characterization of ionic organotin compounds [R2SnCl2(2-quin)](HNEt3) and crystal structures of [(2,4-Cl2-C6H3CH2)2SnCl2(2-quin)](HNEt3)

Eight ionic organotin compounds [R₂SnCl₂(2-quin)]⁻(HNEt₃)⁺ have been synthesized by reactions of 2-quinH with R₂SnCl₂ (R = PhCH₂1, 2-Cl-C₆H₄CH₂2, 4-Cl-C₆H₄CH₂3, 2-F-C₆H₄CH₂4, 4-F-C₆H₄CH₂5, 4-CN-C₆H₄CH₂6, Ph 7, 2,4-Cl₂-C₆H₃CH₂8) in the presence of organic base NEt₃, and their structures have been characterized by elemental analysis, IR and multinuclear NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopies. The structure of [(2,4-Cl₂-C₆H₃CH₂)₂SnCl₂(2-quin)]⁻(NEt₃)⁺ (8) has been determined by X-ray diffraction study. Studies show that compound 8 has a monomeric structure with the central tin atom six-coordinate in a distorted octahedral configuration and the nitrogen atoms of the 2-quin ligands are coordinating to the tin atom in all the eight compounds.     

Fabrication of poly(dimethylsiloxane) microfluidic system based on masters directly printed with an office laser printer

Applications of poly(dimethylsiloxane) (PDMS)-based microfluidic systems are more popular nowadays. Previous fabrication methods of the masters for PDMS microchannels require complicated steps and/or special device. In this paper, we demonstrated that the toner printed on the transparency film with the office laser printer (1200 dpi) can be used as the positive relief of the masters. The transparency film was printed in two steps in order to obtain the same printing quality for the crossed lines. With the laser-printed master, the depth of the fabricated PDMS microchannels was ca. 10 microm and the smallest width was ca. 60 microm. Surface characteristics of the PDMS/PDMS microchannels were performed with SEM. Their electrokinetic properties were investigated by the aids of the measurement of electroosmotic flow (EOF) and the Ohm's curve. Using the PDMS/PDMS microchip CE systems, electroactive biological molecules and non-electroactive inorganic ions were well separated, respectively. This simple approach could make it easy to carry out the studies of PDMS microfluidic systems in more general labs without special devices.     

Comparison of the structures of an atomic three-valence-electron system with a nuclear three-valence-neutron system

A comparison has been made between the states of a 3-valence-electron system and a 3-valence-neutron system. The fermions are supposed to move in a sphere. The structures and internal motions of the head-states (the lowest of a given^2S+1 L ) of these systems havingL=0,S=1/2 and 3/2, and even and odd parity have been investigated. We have found that the symmetry governing the particular quantum system plays an essential role. In particular, all the nodal surfaces in the head-states originate from symmetry but not from dynamics. Consequently, the head-states of different dynamic systems have similar structures and similar internal motions.     

Radiation from hot spots orbiting an extreme Reissner-Nordström black hole

The general-relativistic effects of an extreme Reissner-Nordström black hole on the flux of radiation emitted by a hot spot orbiting the hole with a thin accretion disk are investigated. The light curves, the redshift factor, and the solid angle against the spot orbit position are given. The results are then compared with those of a spot orbiting a Schwarzschild black hole.     

Influence of Light Scattering by Residual Alumina Nanoparticles on the Analysis of Surfactants Adsorption Using Spectroscopy

The adsorption of a surfactant mixture, based on an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS) and a nonionic surfactant (Triton X-100, or TX100), on alumina nanoparticles was determined by solution depletion method combined with spectrometric measurement. It is shown that the light scattering, originated from the residual adsorbent alumina particles in the supernatant after centrifugation separation, interferes with the measurements of absorbance of the surfactant molecules, and therefore constitutes an error source for determination of the surfactant concentration in the supernatant by spectrometric means. The intensity of this light scattering, namely the influence of the residual alumina nanoparticles upon the surfactant adsorption, was related to the surfactant adsorption and its equilibrium concentration and varied among a batch. In this paper we report a Kalman filter method in order to eliminate the variational scattering background caused by non-separated residual alumina nanoparticles in each supernatant. This method is of interest as it is simple, easy to carry out and of high precision.     

The effect of the third component on butadiene–propylene alternating copolymerization catalyzed by vanadium–aluminum system

The effects of five ethers and four AliBu₂OR's with varied R' on butadiene–propylene alternating copolymerization were investigated. It was found that by adding the proper third component, both the conversion and the catalytic efficiency could be increased. The effect of the third component on the valence state of vanadium ion was also studied. A model of the active center of the ternary-component catalyst system was proposed.     

KINETICS OF SUSPENDED EMULSION POLYMERIZATION OF METHYL METHACRYLATE

The kinetics of suspended emulsion polymerization of methyl methacrylate (MMA), in which water acted as the dispersed phase and the mixture of MMA and cyclohexane as the continuous phase, was investigated. It showed that the initial polymerization rate (Rp0) and steady-state polymerization rate (Rp) were proportional to the mass ratio between water and oil phase, and increased as the polymerization temperature, the potassium persulphate concentration ([I]) and the Tween20 emulsifier concentration ([S]) increased. The relationships between the polymerization rate and [I] and [S] were obtained as follows: Rp0 ∝ [I]0.73[S]0.32 and Rp ∝ [I]0.71[S]0.23. The above exponents were close to those obtained from normal MMA emulsion polymerization. It also showed that the average molecular weight of the resulting poly(methyl methacrylate) decreased as the polymerization temperature, [I] and [S] increased. Thus, MMA suspended emulsion polymerization could be considered as a combination of many miniature emulsion polymerizations proceeding in water drops and obeyed the classical kinetics of MMA emulsion polymerization.