Spectrophotometric Determination of Zirconium in Monazite Sand

A sensitive spectrophotometric method was developed for the determination of zirconium in monazite sand. The zirconium ion was previously separated from the other interfering elements by a 0.5 M thenoyltrifluoroacetone (TTA)-xylene extraction, then determined with Arsenazo III in 9 M HCl medium. Zirconium reacted with Arsenazo III to form an emeraled green coloured complex having maximum absorbance at 665 nm in 9 M HCl medium. The color was stable for at least 2 hours. Effects of time, HCl concentration, gelatine and various ions have been studied. The system confirms the Beer's law over the concentration range investigated. Optimum condition range for measurement in 1.0 cm quartz cell is 0.1–0.5 μg/ml of zirconium. The molar absorptivity is 1.51×10⁵ liter mole^?1 cm^?1. The metal-ligand ratio of 1:4 was confirmed by Job's Continuous Variation method and the conditional stability constant of Zirconium-Arsenazo III Complex in 4 M HCl and 9 M HCl were also determined by this method.     

Flammability studies of 3-methyl pyridine/water system

In industrial processes, information on the safety property of chemicals is essentially crucial for safe handling during unit operations. Ensuring the safe use of combustible or flammable substances in processes is unlikely without detailed investigations of their flammability characteristics and related hazards. We studied 3-methyl pyridine (3-picoline), e.g., flammability limits (LFL/UFL), maximum explosion pressure (P _max), maximum explosion pressure rise (dP/dt)_max, minimum oxygen concentration (MOC), vapor deflagration index (K _g), and characterized the influence of inert steam (H₂O) on critical parameters for 3-picoline/water mixtures at 270°C, 1 atm, various oxygen concentrations, and vapor mixing ratios (100/0, 30/70, 10/90 and 5/95 vol.%) with a 20-L-Apparatus in simulated conditions, respectively. The results showed that the flammability characteristics of 3-picoline_(aq) all increased with the oxygen concentration. However, as the composition of inert steam increased, the flammability parameters and the degree of fire and explosion hazards were significantly reduced, instead. This study elucidated the flammability properties of 3-picoline mixed with inert steam. The conclusions could be applied to proactively prevent the relevant processes from incurring fire and explosion accidents.     

聚乙撑二氧噻吩膜在氧化态的充电过程及电容研究

In this paper, the chronoamperometry was used to study the charging processes of polyethylenedioxythiophene (PEDOT) modified electrodes in the potential range where PEDOT was in the oxidized state. The results show that the charging behaviors of the PEDOT films are well agreed with the exhausted finite diffusion model. The dependence of the capacitance values of the films on potential and concentration of solution was also studied in this potential range.     

Optical measurement of the deformation of giant lipid vesicles driven by a micropipet electrode

We investigate the deformation of giant lipid vesicles driven by a micropipet electrode by use of differential confocal microscopy. This optical technique provides nanometer depth resolution without mechanical contact and hence prevents large tension or perforation of the soft membrane. For dipalmitoyl phosphatidylcholine (DPPC) membranes in the gel phase, we observed deformations of several hundreds of nanometers when the driving voltage was about 0.1 V. The voltage and frequency responses of the vesicle deformation can be explained by the balance between the electroosmotic force inside the micropipet and the membrane tension. We also used DPPC:cholesterol vesicles to check the validity of this model. In the fluid phase, however, the deformation is independent of the modulation signal because micrometer-scale thermal fluctuations dominate the membrane motion.     

Mammalian cell growth studiedin situ by fourier transform infrared spectroscopy

Fourier transform infrared techniques were used to monitor mammalian cell growth plated on attenuated total reflection (ATR) crystals. Consistently, the growth kinetics plots generated from the obtained spectra demonstrated a sigmoidal curve representing a sequence of slow, rapid, then tapering cell growth which correlated well with non-spectral cell growth determinations. Significant advantages over traditional methods of measuring cell growth kinetics are demonstrated. The technique has promising potential to be used to study events in areas such as toxicology and cell biology.     

Analysis of double-stranded DNA by microchip capillary electrophoresis using polymer solutions containing gold nanoparticles

The impact of gold nanoparticles (GNPs) on the microchip electrophoretic separation of double-stranded (ds) DNA using poly(ethylene oxide) (PEO) is described. Coating of the 75-microm separation channel on a poly(methyl methacrylate) (PMMA) plate in sequence with poly(vinyl pyrrolidone), PEO, and 13-nm GNPs is effective to improve reproducibility and resolution. In this study, we have also found that adding 13-nm GNPs to 1.5% PEO is extremely important to achieve high resolution and reproducibility for DNA separation. In terms of the stability of the GNPs, 100 mM glycine-citrate buffer at pH 9.2 is a good buffer system for preparing 1.5% PEO. The separation of DNA markers V and VI ranging in size from 8 to 2176 base pairs has been demonstrated using the three-layer-coated PMMA microdevice filled with 1.5% PEO containing the GNPs. Using these conditions, the analysis of the polymerase chain reaction products of UGT1A7 was complete in 7 min, with the relative standard deviation values of the peak heights and migration times less than 2.3% and 2.0%, respectively. In conjunction with stepwise changes of the concentrations of ethidium bromide (0.5 and 5 microg/ml), this method allows improved resolution and sensitivity for DNA markers V and VI.     

Double-Label Simultaneous Time-Resolved Fluoroimmunoassay of Phenytoin and Phenobarbital

A procedure for the simultaneous time-resolved fluoroimmunoassay for phenobarbital and phenytoin, based on the use of europium- and samarium-labeled haptens, has been investigated. These lanthanide ions are bound to the haptens by means of the anhydride of diethylenetriaminepentaacetic acid. The antibody is immobilized onto immunoplate in which samples are assayed in competitive immunoassay. After the immunoreactions and dissociation with a fluorescence enhancement solution, the fluorescence intensity is measured. The detection limits of the assay are, respectively, 20 ng/ml for phenobarbital and 50 ng/ml for phenytoin. Results obtained with the proposed methods correlate well (CV <10%). The inter-reactions between phenobarbital, phenytoin, and their antibodies are studied.     

离聚体溶液

离聚体（ionomer）是指含离子基团低于15mol％的聚合物，这些离子基团能聚集成多重离子对[1]或离子簇[2-6]，使大分子链发生物理文联形成聚集体，导致性质起很大变化。例如常温下因物理交联而具有良好弹性，而高温时物理交联被破坏而具有流动性，所以离聚体能制成热塑性弹性体。由于物理交联存在，离聚体不能轻易溶于非极性溶剂中；由于离子含量低，又不易溶于水或其它强极性溶剂中．因此，尽管离聚体固体的研究和应用已有40多年的历史，但有关溶液研究的报导到70年代末才见发表[7-9]，近10年取得较大进展，其独特的粘度关系使人们考虑利用…     

Solar Photocatalytic Degradation of 4‐Chlorophenol in Kaolinite Catalysts

This research applies semiconductor photocatalysts, which are formed by metal ion exchange on the surface of kaolinite catalyst with cations, to the study of photocatalytic degradation of 4‐chlorophenol. The analysis results of catalyst properties shows that, after sintering at 400 °C, kaolinite catalyst has a particle size of between 10–100 nm indicating the nano level of synthesized catalysts. Under the same condition, kaolinite‐Ag/Zn catalyst works better in degradation efficiency than single kaolinite‐Ag and kaolinite‐Zn catalysts. Kaolinite‐Zn catalyst declines in degradation efficacy after 150 minutes and performs poorer than the other three types of kaolinite catalysts. In the experiments of different amounts of catalysts, when the concentration exceeds 0.1 wt%, utilization of light energy and degradation efficiency will be reduced due to shielding effect. When at different pH values, the higher the pH value, the more OH‐will be released and that is beneficial for reaction with substances and the increase of reaction rate. Finally multivariate analysis proves that there is one determining factor that influences the photocatalytic degradation of 4‐chlorophenol in kaolinite catalysts, named as “the factor with intermediates competition degree,” the one affecting the 4‐CP degradation at different weight percentages that is referred to as the “shielding effect factor.”     

一种新的判断高分子相容性的粘度判据

依据最近提出的高分子稀溶液粘度的浓度 依赖性的团簇理论 ,对高分子‘理想混合物’的定义进行了更新的理论分析 .在此基础上提出了一个新的判定高分子相容性的粘度判据 .从现有的大量实验数据看 ,该判据是和事实相符合的