Features of the Motion of a Gas-Liquid Medium in a Compound Shell (Sphere and Truncated Cone) Subject to Vibration

The results from an experimental study into the dynamic behavior of a gas-liquid medium and solid particles in a compound shell (sphere-truncated cone) are reported on. The following processes are studied: formation of gas bubbles and their clusters, strong macroflows, and intensive chaotic motion of the medium in the truncated cone as a nonlinear vibrating liquid-gas system__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 1, pp. 112–118, January 2005.     

Two compounds constructed from Strandberg-type polyoxoanions,metals and organic ligands

Two new hybrid compounds, [Cu(1)(phen)(H₂O)][Cu(2)(phen)(H₂O)]([Cu(3)]_0.25(H₂O)][P₂Mo₅O₂₃]·3.75H₂O (1) and [Cu(en)₂]_1.5[P₂Mo₅O₂₃]₂·(enH₂)₃·2H₂O (2) (phen = 1,10-phenanthroline, en = ethylenediamine), have been hydrothermally synthesized and characterized by IR, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), powder XRD analyses, TG analyses, cyclic voltammogram analyses, elemental analyses, and single crystal X-ray diffraction analyses. Single crystal X-ray diffraction analyses reveal that the two compounds have a 1-D chain structure formed by Strandberg-type POMs and TMCs with –A–B–C–B–A–B–C–B– linking mode, then further extend into a 2-D layer structure through π?π or hydrogen bond interactions.     

一类高阶代数微分方程的亚纯允许解

利用亚纯函数的Nevanlinna值分布理论,研究了一类高阶微分方程具有亚纯允许解时,它所具有的形式,得到了一个Malmquist型定理。     

Accumulation of arsenic(III) by chlorella vulgaris

Arsenic occurs naturally in the environment and also through agricultural and industrial pollution. Since arsenic species show different toxicities, it is important to be able to separate them. Methods using microorganisms are being applied increasingly to remove metal ions and different metal species from aqueous solutions. Accumulation of As(III) by Chlorella vulgaris algae was studied, including various factors that influence on accumulation capacity, e.g. pretreatment of the algae (live, dry and lyophilized algae), temperature (4, 22, 37 and 100 °C), pH and exposure time of the algae to arsenic solutions. The pH appears to be the most critical factor, probably due to the species presenting different charges with pH variation. For arsenic species determination, hydride generation atomic absorption spectrometry (HG–AAS) was employed. Copyright © 1999 John Wiley & Sons, Ltd.     

Sesbania drummondii cell cultures: ICP-MS determination of the accumulation of Pb and Cu

Sesbania cell cultures grown in the presence of different concentrations of Pb (0-1000 mg/L) and Cu (0-500 mg/L) were assayed for growth, metal accumulations and activities of antioxidative enzymes: superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX). These cultures tolerated Pb up to a concentration of 500 mg/L, registering a fresh weight growth of 500% in 3 weeks. At the same time, cultures registered a growth of 200% in 3 weeks at a Cu concentration of 100 mg/L showing less tolerance than Pb. However, Sesbania cells accumulated more Cu than Pb, as determined by ICP-MS, at all the treatments tested. Cu accumulation reached 3000 mg/kg (dry weight) at a Cu treatment of 100 mg/L, while Pb accumulation was only over 150 mg/kg (dry weight) at 500 mg Pb/L. Metal accumulations were positively correlated with induction of SOD and CAT activities in both the metal treatments. SOD activity of callus was 105 U/mg (fresh weight) at a Pb treatment of 500 mg/L and the corresponding Pb accumulation of 160 mg/kg (dry weight), while the activity rose to 300 U/mg (fresh weight) at a Cu treatment of 100 mg/L and the corresponding Cu accumulation of 3000 mg/kg (dry weight). The pattern of GPX activities was, however, different, particularly in Pb treatments where activities declined with increasing concentrations of Pb in the cells as well as growth medium. This study shows how Sesbania cells withstand heavy metal stress by induction of antioxidative enzyme activities.