Study on transfer and interfacial kinetics of neodymium and samarium in membrane based extraction

Extraction and interfacial kinetics of Nd3+ and Sm3+ with HER/EHP-kerosene in a hollow fiber membrane extractor were studied. The results show that the extraction reactions in the hollow fiber membrane extractor are the same as those in the liquid-liquid extraction, which can be expressed as a quasi-first-order reaction. The effect of acidity in aqueous phase, concentrations of extractant, Nd3+ and Sm3+ on extraction rate were discussed and the corresponding reaction series were obtained. The reaction equations, reaction rate constants and the separation constant were obtained.

Kinetics and mechanism of Y(III) extraction with CA-100 using a constant interfacial cell with laminar flow

The Yttrium(III) extraction kinetics and mechanism with secnonylphonoxy acetic acid (CA-100) were investigated by a constant interfacial cell with laminar flow. The studies of interfacial tension and solubility of extractant and effects of the stirring rate, temperature, specific interfacial area and species concentration on the extraction rate showed that the extraction regime was dependent on the extraction conditions and the most probable reaction zone was at the liquid-liquid interface. The rate equation of extracting yttrium by CA-100 in heptane was Rf = k[Y3+]((a))[H(2)A(2)]((o))(0.88)[H+]((a))(-1.08).

SOLVENT-EXTRACTION OF SC(III), ZR(IV), TH(IV), FE(III), AND LU(III) WITH THIOSUBSTITUTED ORGANOPHOSPHINIC ACID EXTRACTANTS

The solvent extraction of Sc(III), Zr(IV), Th(IV), Fe(III) and Lu(III) with Cyanex 302 (bis(2,4,4-trimethylpentyl)monothiophosphinic acid) and Cyanex 301 ( bis(2,4,4-trimethylpentyl) dithiophosphinic acid) in n-hexane from acidic aqueous solutions has been investigated systematically. The effect of equilibrium aqueous acidity on the extraction with these reagents was studied. The separation of Th(IV), Fe(III) and Lu(III) from Sc(III), or the separation of other metals from Lu(III) with Cyanex 302, can be achieved by controlling the aqueous acidity. However, Cyanex 301 exhibited a poor selectivity for the above metals, except for Lu(III). The extraction of these metals with Cyanex 272, Cyanex 302 and Cyanex 301 has been compared. The stripping percentages of Sc(III) for Cyanex 302 and Cyanex 301 in a single stage are near 78% and 75% with 3.5 mol/L and 5.8 mol/L sulphuric acid solutions, respectively. The effects of extractant concentration and temperature on the extraction of Sc(III) were investigated. The stoichiometry of the extraction of Sc(III) with Cyanex 302 was determined. The role of different components of Cyanex 302 in the extraction of Sc(III) was discussed.

EXTRACTION MECHANISM OF SC(III) AND SEPARATION FROM TH(IV),FE(III) AND LU(III) WITH BIS(2,4,4-TRIMETHYLPENTYL)PHOSPHINIC ACID IN N-HEXANE FROM SULFURIC-ACID-SOLUTIONS

The extraction equilibrium data of sulphuric acid and scandium(III) with bis(2,4,4-trimethylpentyl)phosphinic acid (H[BTMPP]) from sulphuric acid solutions have been obtained. There are two extraction mechanisms of scandium(III) with H[BTMPP] at different

Extraction behavior of Mo and W as homologs of Sg with α-benzoinoxime

Solvent extraction of molybdenum and tungsten as homologues of Sg with a-benzoinoxime from HCl solutions has been investigated. The extraction equilibration was achieved at 20s for Mo and W. Molybdenum was almost quantitatively extracted from 0.001 to 4M HCl solutions, and the extraction yields decreased at higher and lower acid concentrations due to the formation of anionic oxychloride complex and anionic species MO42-, respectively. The extraction yield of W was lower than that of Mo during the whole range of acid concentration. The composition of the extracted species was determined by using the slope method in present experiment. The elemental analysis, IR and 1H NMR spectra of the extracted species suggest that the extracted complex contain one MoO22+or WO22+ groups bonded with two a-benzoinoxime molecules.

The study of immersion chloride extraction of iron artifacts

The chloride extraction rules of iron artifacts were studied by immersion methods. Different chloride extraction results between the alkaline solution and a washing solution were obtained. The microstructure and the anti-corrosion performance of the samples before and after treatment, were, respectively studied by the scanning electron microscope (SEM) and the potentiodynamic scanning method. The results indicated that Cl- removed according to the diffusion law. The microstructure of the samples transformed after treatment. The rusts became more compact, and the porosity also increased. The chloride extraction effect in the washing solution was better than that in the NaOH solution.

Extraction of Nitraria tangutorum seed oil by supercritical carbon dioxide and determination of free fatty acids by HPLC/APC/IMS with fluorescence detection

The seed oil from Nitraria tangutorum samples was obtained by supercritical carbon dioxide extraction methods. The extraction parameters for this methodology, including pressure, temperature, particle size and extraction time, were optimized. The free fatty acids in the seed oil were separated with a pre-column derivation method and 1,2-benzo-3,4-dihydrocarbazole-9-ethyl-p-toluenesulfonate (BDETS) as a labeling regent, followed by high-performance liquid chromatography (HPLC) with fluorescence detection. The target compounds were identified by mass spectrometry with atmospheric pressure chemical ionization (APCI in positive-ion mode). HPLC analysis shows that the main compositions of the seed oil samples were free fatty acids (FFAs) in high to low concentrations as follows: linoleic acid, oleic acid, hexadecanoic acid and octadecanoic acid. The assay detection limits (at signal-to-noise of 3:1) were 3.378-6.572 nmol/L. Excellent linear responses were observed, with correlation coefficients greater than 0.999. The facile BDETS derivatization coupled with mass spectrometry detection allowed the development of a highly sensitive method for analyzing free fatty acids in seed oil by supercritical CO2 extraction. The established method is highly efficient for seed oil extraction and extremely sensitive for fatty acid profile determination. (C) 2007 Elsevier B.V. All rights reserved.

Energy transfer and infrared-to-visible upconversion luminescence of Er3+/Yb3+-codoped halide modified tellurite glasses

We report on the energy transfer and frequency upconversion spectroscopic properties of Er3+-doped and Er3+/Yb3+-codoped TeO2-ZnO-Na2O-PbCl2 halide modified tellurite glasses upon excitation with 808 and 978 nm laser diode. Three intense emissions centered at around 529, 546 and 657 nm, alongwith a very weak blue emission at 4 10 nm have clearly been observed for the Er3+/Yb3+-codoped halide modified tellurite glasses upon excitation at 978 nm and the involved mechanisms are explained. The quadratic dependence of fluorescence on excitation laser power confirms the fact that the two-photon contribute to the infrared to green-red upconversion emissions. And the blue upconversion at 410 nm involved a sequential three-photon absorption process. (c) 2005 Elsevier Ltd. All rights reserved.

Phylogeny and biogeography of the Petaurista philippensis complex (Rodentia : Sciuridae), inter- and intraspecific relationships inferred from molecular and morphometric analysis

With modified DNA extraction and Purification protocols, the complete cytochrome b gene sequences (1140 bp) were determined from degraded museum specimens. Molecular analysis and morphological examination of cranial characteristics of the giant flying squirrels of Petaurista philippensis complex (P. grandis, P. hainana, and P. yunanensis) and other Petaurista species yielded new insights into long-standing controversies in the Petaurista systematics. Patterns of genetic variations and morphological differences observed in this study indicate that P. hainana, P. albiventer, and P. yunanensis can be recognized as distinct species, and P. grandis and P. petaurista are conspecific populations. Phylogenetic relationships reconstructed by using parsimony, likelihood, and Bayesian methods reveal that, with P. leucogenys as the basal branch, all Petaurista groups formed two distinct clades. Petaurista philippensis, P. hainana, P. yunanensis, and P. albiventer are clustered in the same clade, while P. grandis shows a close relationship to P. petaurista. Deduced divergence times based on Bayesian analysis and the transversional substitution at the third codon suggest that the retreating of glaciers and upheavals or movements of tectonic plates in the Pliocene-Pleistocene were the major factors responsible for the present geographical distributions of Petaurista groups. (c) 2005 Elsevier Inc. All rights reserved.

Identification and characterization of a novel envelope protein in Rana grylio virus

Viral envelope proteins have been proposed to play significant roles in virus infection and assembly. In this study, an envelope protein gene, 53R, was cloned and characterized from Rana grylio virus (RGV), a member of the family Iridoviridae. Database searches found its homologues in all sequenced iricloviruses, and sequence alignment revealed several conserved structural features shared by virus capsid or envelope proteins: a myristoylation site, two predicted transmembrane domains and two invariant cysteine residues. Subsequently, RT-PCR and Western blot detection revealed that the transcripts encoding RGV 53R and the protein itself appeared late during infection of fathead minnow cells and that their appearance was blocked by viral DNA replication inhibitor, indicating that RGV 53R is a late expression gene. Moreover, immunofluorescence localization found an association of 53R with virus factories in RGV-infected cells, and this association was further confirmed by expressing a 53R-GFP fusion protein in pEGFP-N3/53R-transfected cells. Furthermore, detergent extraction and Western blot detection confirmed that RGV 53R was associated with virion membrane. Therefore, the current data suggest that RGV 53R is a novel viral envelope protein and that it may play an important role in virus assembly. This is thought to be the first report on a viral envelope protein that is conserved in all sequenced iridoviruses.

Isolation, characterization and genome sequence of a birnavirus strain from flounder Paralichthys olivaceus in China

A birnavirus strain, Paralichthys olivaceus birnavirus (POBV), was isolated and characterized from cultured flounder in China, and its complete genomic sequence was subsequently determined. The virus could induce cytopathic effects (CPE) in four of seven fish cell lines and was resistant to chloroform, 5-iodo-2'-deoxyuridine, acid and alkaline pH, and heat treatment. Purified virus particles had a typical icosahedral shape, with a diameter of approximately 55-60 nm. The genomic segments A and B of POBV were 3,091 and 2,780 bp in length and shared many of the features of the members of the family Birnaviridae. Segment A contained two partially overlapping ORFs encoding a polyprotein, pVP2-VP4-VP3, and a nonstructural protein, VP5, while segment B had only one ORF encoding for the VP1, a viral RNA-dependent RNA polymerase (RdRp). This is the first report about a birnavirus strain from a new non-salmonid host in China and its complete genome sequence.

Determination of 266 pesticide residues in apple juice by matrix solid-phase dispersion and gas chromatography-mass selective detection

A macro matrix solid-phase dispersion (MSPD) method was developed to extract 266 pesticides from apple juice samples prior to gas chromatography-mass selective detection (GC-MSD) determination. A 10 g samples was mixed with 20 g diatomaceous earth. The mixture was transferred into a glass column. Pesticide residues were leached with a 160 mL hexane-dichloromethane (1:1) at 5 mL/min. Two hundred and sixty-six pesticides were divided into three groups and detected by GC-MSD under selective ion monitoring. The proposed method takes advantage of both liquid-liquid extraction and conventional MSPD methods. Application was illustrated by the analysis of 236 apple juice samples produced in Shaanxi province China mainland this year. (C) 2004 Elsevier B.V. All rights reserved.

Kinetics of alkaline phosphatase in lake sediment associated with cage culture of Oreochromis niloticus

Variations in kinetics of alkaline phosphatase occurring in different sites of sediment associated with cage culture of Oreochromis niloticus in a shallow Chinese freshwater lake (Lake Donghu) were described. In addition, the kinetic parameters of each 2.5-cm stratum in the sediment from the surface down to 37.5 cm were analyzed. Horizontally, the V-max values of alkaline phosphatase in surface sediments increased markedly at sites immediately under and adjacent to the cage that would be subjected to the deposition of fish feces. Peak V-max values in the top 5 cm of the sediment under the cage were also observed relative to their deeper control. After a treatment where the fish feces were added over 12 days, the sediment in deeper layer exhibited a significantly higher V-max value, thereby corroborating the relationship between V-max values of alkaline phosphatase and fish feces in sediments. The fish feces exhibited a remarkable alkaline phosphatase activity (APA). Thus, it is indeed a source of the enzyme. Effects of the fish feces were dose- and time-dependent. The V-max values in sediments were always stimulated, but the K-m values showed much more variability. (C) 2001 Elsevier Science B.V. All rights reserved.

Analysis of organchlorine compounds in water by solid phase microextraction and gas chromatography

In this work, both,solid phase microextraction (SPME) and solid phase extraction(SPE) were used to enrich organochlorine compounds in water samples and analyzed by gas chromatography with electron capture detector. The operating conditions of SPME have been studied and different kinds of solid phase were compared. Linear alkybenzene sulfonate(LAS) was added to the samples to investigate its effect on the analysis. The results indicated that polyacrylate was better than other commercial solid phases in extraction of moderated polar organic compounds and the sensitivity of SPME was higher than SPE. LAS affect much in liquid-liquid extraction and headspace SPME; but it has little effect on SPE and direct-SPME method. The applications showed that SPME was a fast and effective method in sample preparation.

Fabrication and optical characterization of GaN-based nanopillar light emitting diodes

InGaN/GaN-multiple-quantum-well-based light emitting diode ( LED) nanopillar arrays with a diameter of approximately 200nm and a height of 700nm are fabricated by inductively coupled plasma etching using Ni self-assembled nanodots as etching mask. In comparison to the as-grown LED sample an enhancement by a factor of four of photoluminescence ( PL) intensity is achieved after the fabrication of nanopillars, and a blue shift and a decrease of full width at half maximum of the PL peak are observed. The method of additional wet etching with different chemical solutions is used to remove the etch-induced damage. The result shows that the dilute HCl ( HCl:H2O=1:1) treatment is the most effective. The PL intensity of nanopillar LEDs after such a treatment is about 3.5 times stronger than that before treatment.