Polymers from 12-hydroxymethyltetrahydroabietic acid and its vinyl and acrylate esters

12-Hydroxymethyltetrahydroabietic acid has been homopolymerized by melt condensation and homopolyester has been obtained. Vinyl 12-hydroxymethyltetrahydroabietate has been prepared from 12-hydroxymethyltetrahydroabietic acid by vinyl interchange procedure with vinyl acetate, and has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, and terpolymerized with styrene and acrylonitrile. The acrylate ester of 12-hydroxymethyltetrahydroabietic acid also has been prepared from 12-hydroxymethyltetrahydroabietic acid and acrylyl chloride. The acrylate thus obtained has been homopolymerized and copolymerized with vinyl chloride and vinyl acetate. Polymers thus obtained have been characterized.     

超声幅照下ABS塑料表面的粗化研究

由于外层镀有金属的塑料制品兼有塑料及金属材料的优点,因而是一类具有广泛用途的新型复合材料。其中以金属化的ＡＢＳ塑料的应用最为广泛。＊＊Ｓ塑料金属化的方法很多,其中以电镀法最受重视ｌ‘］。为保证金属镀层与塑料表面具有良好结合力,使塑料表面形成四坑、微孔等均匀微观粗糙状态的粗化工艺是相当关键的步骤之一ｐ‘。现国内外广泛采用铬一硫酸混合液的化学粗化法,但该法对环境污染较大。随着环保要求的日益高涨,其它粗化法越来越受到人们的重视［’］。本文探索了利用超声波的空化效应来粗化ＡＢＳ塑料表面、为ＡＢＳ塑料的电…     

A new nebulizer for atomic spectrometry

The rotating disc nebulizer has been redesigned with respect to the principle parameters that determines its analytical performance. The flow pattern of the aerosol attained has been optimized by altering the shape of the inner chamber of the nebulizer to obtain optimum aerodynamic characteristics. The optimum angle of impact and "free flight" distance has been established using particle size distribution and mass transport efficiency as criteria. Analytical characteristics have been determined by monitoring the emission signal from aqueous standards. The accuracy has been assessed by using reference steel samples. Using standard solutions of different viscosity the performance of the nebulizer with respect to viscosity changes of the sample has been compared with that of a commercial Meinhardt nebulizer. The rotating disc nebulizer has been less affected by changes in viscosity making it possible to use this nebulizer with slurry and oil samples.     

Improvement of properties of silica‐filled styrene‐butadiene rubber composites through plasma surface modification of silica

The performance of plasma surface modified silica filler in styrene‐butadiene rubber (SBR) matrix has been analyzed. The conditions of plasma modification have been optimized by taking secant modulus as a standard parameter and the occurrence of the modification has been confirmed by surface area determination and Fourier transform infrared spectroscopy. The plasma‐modified surface of silica has been found to be composed of carbon–carbon double bonds and carbon–hydrogen bonds. Silane treatment also has been carried out on silica filler surface for a comparative assessment of its influence in the curing behavior and filler–rubber interaction. The cure reactions of all the rubber compounds have been found to be proceeded according to first‐order kinetics. A reduction in the cure reaction rate constant has been observed with the loading of unmodified and surface modified silica, emphasizing the cure deactivation of the matrix rubber by the silica filler. The filler dispersion, as revealed by scanning electron microscopy, has been found to be greatly improved by the plasma as well as silane treatment. The filler–rubber interaction has been found to be greatly improved by both surface treatments, but the best balance of mechanical properties has been observed with plasma surface modification only. Copyright © 2004 John Wiley & Sons, Ltd.     

A fluorimetric and circular dichroism study of hemoglobin--effect of pH and anionic amphiphiles

In this work, bovine hemoglobin (Hb) has been studied mainly by the fluorescence method. pH has been found to exert a profound effect on Hb structure. This has been confirmed by fluorescence and circular dichroism (CD) studies. The pH-induced change in quaternary structure of Hb indirectly affects its secondary structure. This in turn affects ligand binding to Hb at various pH. The binding of two amphiphiles, a bile salt and a surfactant, have been investigated. The pH-induced structural modification of Hb has been confirmed by studies with the well-known denaturant urea and the polarity probe ANS, which has been used as an extrinsic fluorophore.     

Indirect atomic absorption spectrophotometric determination of arsenic

Arsenic has been determined indirectly by atomic absorption spectroscopy by estimating molybdenum in a solution of arsenomolybdic acid in methyl isobutyl ketone. Interference from other ions has been eliminated by prior extraction of arsenic as the diethyldithiocarbamate in diethyl ether. Arsenic has been determined in the presence of phosphate, silicate and germanium (IV). The method has also been used for the determination of arsenic in organic material.     

量子化尺寸纳米颗粒及其在生物体系中的作用

本文从胶体化学与物理化学的角度介绍了纳米颗粒的尺寸量子化效应。介绍了作者所进行的纳米颗粒在生物体系中的应用工作。纳米颗粒金和二氧化硅能显著地提高葡萄糖氧化酶的生物活性。纳米颗粒金能提高视黄醛仿生膜的光电响应电流和寿命。作者用纳米颗粒的吸附浓集效应、吸附定向效应、和量子尺寸效应来解释这些效应     

Alpha-cyclodextrin functionalized CdS nanocrystals for fabrication of 2/3 D assemblies

Different types of cyclodextrins (CDs) have been tested as mediators for the water phase transfer of organic-capped CdS nanocrystals (NCs), and alphaCD has been demonstrated to be the most effective system. The formation of a complex based on alphaCDs and colloidal NCs has been considered to be responsible for the phase transfer process and extensively investigated by optical, structural, and calorimetric measurements, as a function of the experimental parameters (pH and NC and CD concentration). A mechanism for the complexation phenomena has been suggested. The fabrication of 2/3 D supramolecular architectures has been proposed according to two different strategies. First, a layer-by-layer procedure has been used to obtain multilayered structures where polyelectrolyte layers have been intercalated with negatively charged alphaCD-CdS NC complexes by exploiting electrostatic interaction between polyelectrolyte and cyclodextrin OH groups. Second, a monolayer of CdS NCs has been deposited onto a self-assembled monolayer of sulfated CDs, thus combining the use of an electrostatic-force-based approach and host-guest chemistry. The important role played by host-guest interactions has then been revealed.     

Modification of Chemically Amplified Resists by Radical Copolymerization

Modification of a phenolic resist has been carried out by copolymerization with methacrylic monomers. Influence of irradiation source and its intensity has been studied by analyzing sensitive curves of a various resist composition. Inversion of imaging type at varying post exposure bake temperature has been investigated for resists based on copolymers containing methacrylic acid units, which has been related with crosslinking of macromolecules.     

Kinetics and mechanism of the production of higher olefins from stearic acid in the presence of an alumina-supported nickel sulfide catalyst

A nickel sulfide catalyst which efficient in the decarbonylation of fatty acids to olefins and dienes has been obtained for the first time by treating alumina-supported nickel sulfate with hydrogen, and its properties have been studied. In its presence, the olefin selectivity of the reaction can exceed 90%. The kinetics of stearic acid deoxygenation to heptadecenes has been investigated, a kinetic model has been constructed, and a mechanism has been proposed for the reaction over this catalyst. Olefin oligomerization is the dominant side reaction. Kinetic evidence for the catalytic inhibition of oligomerization by nickel hydrides formed on the catalyst has been obtained. The compositions of active site–reactant adsorption complexes have been discussed.     

Polymers from 12 α-hydroxymethylabiet-7,8-enoic acid and vinyl 12 α-hydroxymethylabiet-7,8-enoate

12 α-Hydroxymethylabiet-7,8-enoic acid has been homopolymerized by melt condensation, and a partially crystalline polyester has been obtained. Vinyl 12 α-hydroxymethylabiet-7,8-enoate has been prepared from 12 α-hydroxymethylabiet-7,8-enoic acid by vinyl interchange with vinyl acetate and has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, butadiene, and acrylonitrile, and terpolymerized with styrene and acrylonitrile. Polymers thus obtained have been characterized.     

Synthesis of Hydrogenated Graphene during Acetylene Conversion in Helium Plasma Jet

Hydrogenated graphene has been synthesized in one step by acetylene conversion in a helium plasma jet. A dc plasma torch with a diverging anode channel and a power up to 45 kW has been used to generate plasma. The obtained graphene materials have been studied by scanning electron microscopy, Raman spectroscopy, and elemental analysis. Hydrogen desorption from the samples synthesized has been studied by thermal analysis as a function of temperature. It has been found that during annealing in vacuum, the synthesis products change their morphology because of hydrogen release.     

A comparative study on direct and indirect electrochemical oxidation of polyaromatic compounds

This study has been performed to investigate the treatment of an industrial wastewater containing naphthalene- and anthraquinone-sulfonic acids, by direct and indirect electrolyses. The direct electrochemical oxidation has been carried out using boron-doped diamond and lead dioxide anodes, while the indirect electrolyses has been mediated by active chlorine electrogenerated on a platinum anode, or by hydrogen peroxide electrogenerated on a graphite felt cathode. For each type of electrolyses the effects of operating parameters, such as anode material, current density, chloride concentration, ferrous ions concentrations have been also investigated. Measurements of Chemical Oxygen Demand (COD) and colour fading have been used to compare the results of different electrolyses. Experimental data showed that the complete COD and colour removals have been obtained only by direct oxidation or by active chlorine mediated electrolyses. On the contrary using electrogenerated hydrogen peroxide the solution has been presented a residual COD and colour. In particular, it found that faster oxidation rate has been obtained by direct oxidation using a boron-doped diamond anodes at low current density.     

Observation of OD- by microwave spectroscopy

For the first time the rotational spectrum of the molecular anion OD- has been observed by microwave spectroscopy. OD- has been produced both by a positive and negative glow discharge; by investigating the Doppler shift in both cases, the unshifted frequency of the J=1<--0 rotational transition has been derived. This allowed us to improve the value of the ground-state rotational constant: B(0)=299 264.940(90) MHz. In order to assess that a negative ion has really been observed, the cation N2H+ has been produced and investigated in the same experimental conditions.     

Effect of the intercalated cation on the properties of poly(o-methylaniline)/maghnite clay nanocomposites

A detailed study about the synthesis, characterization and properties of poly(o-methylaniline)(PoMea)/maghnite nanocomposites has been performed. Changes in the characteristics of the nanocomposites, depending on the intercalated cation between the clay layers before the synthesis, have been observed. Intercalated morphology has been detected by TEM in nanocomposites containing copper-treated maghnite (Magh-Cu), while when maghnite treated with strong acids was used (Magh-H); an exfoliated material has been obtained. Also, remarkable differences in the properties of the polymers have been observed by TG-MS and FTIR, suggesting that the polymer produced with Magh-H has a higher degree of branching. The electrochemical behavior of the polymers extracted from the nanocomposites has been studied by cyclic voltammetry. Good electrochemical response has been observed for PoMea grown into Magh-Cu but not for the one polymerized into Magh-H.     

Preparation of thin films comprising palladium nanoparticles by a solid-liquid interface reaction technique

A new approach to the formation of palladium nanoparticulate films with diameter between 6 and 50 nm by the solid-liquid interface reaction technique (SLIRT) has been presented. A solid film of palladium nitrate was formed by the modified spin coating method. This film is subsequently immersed in a reducing solution to initiate a reaction at the interface and ultimately transforms it to a palladium metal film. The kinetics of palladium reduction has been studied by UV-visible spectroscopy. The characterization of the palladium film has been performed by various physicochemical techniques such as XRD, ED, XPS, SEM, EDX, TEM, and UV-visible spectroscopy. The texture and morphology of the materials has been investigated by atomic force microscopy (AFM). At a constant palladium nitrate concentration, the average diameter of palladium nanoparticles decreases with an increase of hydrazine concentration. The effect of concentration of hydrazine on the particle size has been discussed. The palladium film formation mechanism has been proposed for the SLIRT.     

A study of human coagulation factor XIII A-subunit by electrospray ionisation mass spectrometry

A study of factor XIII A-subunit has been made by electrospray ionisation mass spectrometry. Factor XIII has been isolated and rigorously purified, and the intact A-subunit protein has been analysed to confirm its molecular weight accurately for the first time. Thrombin proteolysis of the A-subunit has been monitored and the resulting cleavage products, the activated A-subunit protein and the Activation Peptide, have been analysed by electrospray ionisation mass spectrometry to confirm the site of proteolysis. Facile and rapid separation of the Activation Peptide from the activated A-subunit protein has been achieved using simple on-line separation techniques. The molecular weight measurements have been repeated numerous times to provide an indication of the precision and variability of the analyses.     

Immunological determination of triazine pesticides bound to soil humic acids (bound residues)

An immunological method for the determination of triazine herbicides covalently bound to soil humic acids has been developed. A sandwich-immunoassay has been performed, based on both polyclonal humic acid-antibodies and monoclonal triazineantibodies. A peroxidase-labelled third antibody has been used for the photometric detection. A triazine-humic acid conjugate served as calibration standard. The coupling density for this conjugate has been determined by measuring the difference of free amino groups both with ninhydrin and with the trinitrobenzene sulfonic acid method. In addition, the coupling density has been confirmed by scintillation counting using a (14)C-atrazine derivative. Due to nonspecific interactions between antibody proteins and humic acids, different blocking steps had to be performed. Finally, the assay has been applied to a triazine contaminated soil sample. Humic acids (including bound residues) have been extracted by diluted sodium carbonate solution. Concentrations of bound atrazine residues have been found in the range of 2 mg/kg soil on fields where triazine herbicides has been applied over a period of 21 years. These results are comparable to both the applied amount and the nonextractable fraction.     

邻苯二甲酸异丙酯酰氧基-丙烯酰氧基-乙酰乙酸乙酯络铝及其聚合物的合成与荧光性质

通过异丙氧基铝和邻苯二甲酸酐、乙酰乙酸乙酯及丙烯酸反应,合成了螯合物单体邻苯二甲酸异丙酯酰氧基-丙烯酰氧基-乙酰乙酸乙酯络铝,由自由基聚合法合成了聚合物,用元素分析仪、VPO、IR、¹HNMR和²⁷AlNMR证实了它们的结构,并研究了它们在DMF中的荧光性质。     

113mIn radioisotope generator system

Tin-indium generator systems were made with commercial hydrated zirconium oxide, silica gel and hydrated zirconium oxide prepared by the AMPHLETT method. The adsorption capacity of tin has been determined by both spectrophotometric analysis and gammaspectrometry. Zirconium break-through has been determined and compared with the literature values. The dependence of the adsorption capacity on the particle size has been investigated. The effect of autoclaving on the generator systems has been examined.