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171.
172.
Paresh Parekh Arpan Parmar Suresh Chavda Pratap Bahadur 《Journal of Dispersion Science and Technology》2013,34(10):1377-1387
In present study, we have investigated the effect of an anionic surfactant sodium dodecyl sulfate (SDS) and clay on calcium alginate beads was studied to remove methylene blue (MB) and to improve the adsorption capacity. The effects of various experimental parameters, such as shaking rate, initial dye concentration, temperature, and pH on the adsorption rate, have been studied. Equilibrium studies showed that the sorption of the dye was enhanced in presence of SDS. Scanning electron microscope (SEM) analysis showed that SDS entrapped beads have more pores and cavities which could be responsible for improved adsorption of MB. The kinetics of cationic dye adsorption nicely followed pseudo-second-order process. The evaluated thermodynamic parameters (ΔG o, ΔH o, ΔS o) suggest endothermic adsorption of MB. The results revealed that the surfactant entrapped alginate could be considered as potential adsorbents for MB removal from aqueous solutions. 相似文献
173.
174.
Raunak Shubhasish Mukherjee Ashok K. Prasad Susan J.C. Schäffer Arthur C. Watterson Virinder S. Parmar 《Tetrahedron》2005,61(23):5687-5697
Regioisomeric spiro-(indoline-isoxazolidines) have been synthesized in moderate yields by the cycloaddition reaction between ethyl (3-indolylidene)acetate and various substituted α,N-diphenylnitrones, using environmentally benign microwave technology. A novel concerted reaction mechanism is described that explains the preferential formation of the regioisomeric spiro-(indoline-isoxazolidine) analogs 6 over 5. These compounds were screened for anti-mycobacterial and anti-invasive activities against tumor cells. 相似文献
175.
Summary An XRF method for the determination of Y, Ce, Pr, Nd, Eu and Gd in high purity samarium oxide is described. Samples in oxalate form are mixed with boric acid in the ratio 31. About 800 mg of the mixture is pressed as a double layer pellet. Experimental parameters are selected to give maximum peak to noise ratio. The analysis lines are chosen after studying line interferences. The estimation limit ranges from 0.005% to 1% for most elements.
Röntgenfluorescenzanalyse von Y, Ce, Pr, Nd, Eu und Gd in Samariumoxid hoher Reinheit
Zusammenfassung Zur röntgenanalytischen Bestimmung von Spuren Seltener Erden in hochreinem Samariumoxid wird die Probe in die Oxalatform übergeführt, mit Borsäure im Verhältnis 31 gemischt und zu je 800 mg in Doppelschichttabletten (über Borsäure) gepreßt. Für ein maximales Peak/Untergrund-Verhältnis wurden die experimentellen Parameter entsprechend ausgewählt. Die benutzten Analysenlinien ergaben sich aus einer Untersuchung der Störungen. Die Erfassungsgrenze liegt zwischen 0,005% und 1%.相似文献
176.
Several 5-aryl- or 5-diphenylmethylhydracrylyl hydrazides were synthesized and converted into 5-aryl- or diphenylmethyl-2-oxazolidones. The latter compounds were further alkylated into their corresponding 5-aryl- or 5-diphenylmethyl-3-alkyl-2-oxazolidones as possible anticon-vusants. 相似文献
177.
A selective and sensitive technique has been developed for detecting and identifying 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in human urine. Using a new, "mixed-mode", bonded silica gel, solid-phase extraction column cartridge, THC-COOH was selectively isolated from urine components. Following extraction, the presence of THC-COOH was confirmed and quantitated using gas chromatography-mass spectrometry (GC-MS) or gas chromatography-flame ionization detection. A linear quantitative response curve for THC-COOH was generated over a concentration range of 10 to 300 ng/ml. Overall extraction efficiency averaged greater than 85% and the quantitative response curve exhibited a correlation coefficient of 0.999. The limit of detection and identification using GC-MS for the drug metabolite was found to be six times below the present NIDA guidelines cut-off concentration of 15 ng/ml. 相似文献
178.
This paper describes the preparation of the halogeno complexes, HgX2(o-R2AsC6H4CO2H) (X = Cl, Br, I, and R = Et; X = Br, I, and R-C6H11) and the carboxylate complexes, M(o-R2-AsC6H4CO2)2nL(M = Cd, R = Et, C6H11 and n = O; M = Zn; R = Et; nL = H2O; M = Zn, R = C6H11, nL = 3H2O; M = Hg, R = p-tolyl, nL = 2H2O; M = Hg, R = Me, Ph; C6H11 and nL = EtOH). The structures already reported for the halogeno complexes with R = Ph, Me, p-tolyl and X = Cl, Br, I, have been revised on the basis of detailed scrutiny of the IR spectral data and all these complexes have been divided into four structural types out of which three retain the acid dimer unit of the free ligand. In the carboxylate complexes the lowering of νs, CO2 band and the marginal change in the νas CO2 band with respect to those of the corresponding ligand sodium salts have been attributed to the existence of a novel resonating chelating system with the possibility of having a ring current. 相似文献
179.
Summary An XRF method for the determination of Eu, Gd, Tb, Dy, Ho, Er and Yb in yttrium oxide has been developed. The samples are converted to yttrium oxalate and presented to the spectrometer in the form of pressed pellets. Philips PW-1220, semiautomatic X-ray spectrometer is used for analysis. Analysis lines have been chosen after careful study of line interferences. The lower estimation limit for Yb is 0.01% and for other elements it is 0.005%. The method has been tested for its accuracy by analysing synthetic samples with known composition.
Bestimmung von häufig vorkommenden Verunreinigungen an Seltenen Erden in Yttriumoxid hoher Reinheit mit Hilfe der Röntgenfluorescenzanalyse
Zusammenfassung Ein Verfahren zur röntgenfluorescenzanalytischen Bestimmung von Eu, Gd, Tb, Dy, Ho, Er und Yb in Yttriumoxid wurde ausgearbeitet. Die Probe wird zu Yttriumoxalat umgesetzt und in Form von Preßtabletten der RFA unterworfen. Das halbautomatische Röntgenfluorescenz-Spektrometer Philips PW-1220 wurde verwendet. Eine sorgfältige Untersuchung der Interferenzen führte zur Wahl der Analysenlinien. Die untere Bestimmungsgrenze liegt für Yb bei 0,01%, für die anderen Elemente bei 0,005%. Die Zuverlässigkeit des Verfahrens wurde anhand von synthetischen Proben bekannter Zusammensetzung geprüft.相似文献
180.
Sunil K. Sharma Sumit Kumar Eugene F. Barry Arthur C. Watterson Virinder S. Parmar 《Microchemical Journal》2008,90(2):89-92
The research described here elucidates the fundamental interactions of various cations with phenolic moieties constituting the side chains of novel copolymers. The phenolic group was chosen because similar interactions of the tyrosine (Tyr) moiety in proteins with alkaline earth cations are of particular interest for some biochemical systems where both the alkaline earth cations and the aromatic compounds are abundant. The present study has revealed the preferred binding site for our polymeric systems. 相似文献