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61.
R. Singh R. M. Misra D. C. Gupta D. D. Shukla M. N. Sharma M. P. Madan 《Zeitschrift für Physik B Condensed Matter》1985,58(2):83-89
The parameterC
1=[(1/K
T
)/P]
T
, which describes the pressure variation of the compressibility, has been examined correlating the thermodynamical and interatomic potential approaches employing fewer approximations than has been usual heretofore. General expressions have been derived forC
1 by including the thermal correction terms, which have generally been ignored in previous studies concerning thermal properties of ionic crystals. The parameterC
1 has also been related to the Grüneisen parameter, , using a relation given earlier. The applicability of the derived equations is investigated and discussed for alkali halides employing few realistic potential forms. A good general accord is found with the available experimental data, which exhibits an essential improvement over other theoretical determinations. 相似文献
62.
The technique of three-phase partitioning (TPP) was used to purify the green fluorescent protein (GFP) in a single step. TPP uses a combination of ammonium sulphate and tert-butanol to precipitate proteins from their crude extracts. In the first round of TPP with 20% ammonium sulphate saturation at the ratio of crude to tert-butanol 1:1 (v/v), most of the GFP remains in the lower aqueous phase. When subjected to a second round of TPP with 60% ammonium sulphate saturation at the ratio of crude to tert-butanol 1:2 (v/v) gives 78% recovery of GFP with a 20-fold purification. The sodium dodecyl sulphate-polyacrylamide gel electrophoretic (SDS-PAGE) analysis of purified preparation shows single band. The fluorescence excitation and emission spectra agreed with values reported in literature. 相似文献
63.
Zusammenfassung Die Nickel- und Zinkkomplexe der Adipinsäure werden polarographisch untersucht. Es zeigt sich, daß Zink reversibel reduziert wird, wogegen Nickel eine irreversible Stufe ergibt. Die Stabilitätskonstanten des Zink—Adipinsäurekomplexes werden nachDeFord undHume berechnet. Der Einfluß des pH-Wertes auf die Zink- und die Nickelstufe wird untersucht. Zink und Nickel werden in Gegenwart vieler störender Kationen halbquantitativ bestimmt.
Mit 7 Abbildungen 相似文献
The said complexes have been studied by polarography. Zn is found to be reversibly reduced while Ni gives an irreversible wave. Stability constants of the Zn complex are calculated byDeFord andHume method. Effect of pH on Zn and Ni wave are reported. Estimations of Zn or Ni are carried out separately or in presence of interfering cations.
Mit 7 Abbildungen 相似文献
64.
Ashok K. Singh Amar Singh Ranjana Gupta Madhu Saxena Bharat Singh 《Transition Metal Chemistry》1992,17(5):413-416
The kinetics of oxidation of three aldoses (glucose, mannose and galactose) byN-bromoacetamide (NBA) in the presence of an alkaline solution of RuO4 as catalyst and Hg(OAc)2 as co-catalyst and as a scavenger for bromide have been investigated. The main products of the oxidation are the corresponding
aldonic acids. The reaction is zero order with respect to aldose and OH−. First order dependence of the reaction on both NBA and RuO4 at low concentrations shifts to zero order at higher concentrations. Addition of acetamide decreases the reaction rate, while
addition of Hg(OAc)2 has the opposite effect. No significant effect of ionic strength was observed. OBr− is postulated as the reactive oxidising species and a mechanism involving co-catalysis by RuO4 and HgII is proposed.
TMC 2588 相似文献
65.
White biotechnology is a fast emerging area that concerns itself with the use of biotechnological approaches in the production
of bulk and fine chemicals, biofuels, and agricultural products. It is a truly multidisciplinary area and further progress
depends critically on the role of chemists. This article outlines the emerging contours of white biotechnology and encourages
chemists to take up some of the challenges that this area has thrown up. 相似文献
66.
67.
Summary Thorium and zirconium can be quantitatively precipitated by quinaldinic acid atph 2.7 and 3, respectively. As the precipitates are of nonstoichiometric composition they are to be ignited to oxides. By this reagent thorium can be quantitatively separated from arsenic (As3+), mercury (Hg2+), rare earths, manganese, magnesium and alkaline earths and zirconium from all the aforesaid ions excepting rare earths which contaminate to a slight extent. 相似文献
68.
A method was developed for direct determination of minor and trace amounts of Cr, Mn, Cu, Ni, Co, Li, Pb, Cd, Bi, Sb, Be and Ag in silicate rock, lake and stream sediments using a microwave oven dissolution method and a multi-element graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background correction device. The measurement technique was also suitable for direct determination of trace and ultra-trace amounts of these elements in drinking and seawater samples. A rock or sediment sample was brought into solution in a Teflon vessel by heating in a microwave oven with a mixture of hydrofluoric acid and aqua regia, followed by a further heating with a mixture of boric acid and ethylenediaminetetraacetic acid. The specified elements were directly determined in a group of four elements in one firing and eight elements in two firings from this solution or from a diluted solution using the optimum operating parameters developed in this work. The method, tested with 23 international reference rocks and sediments and seven international quality control and reference water samples, showed good to excellent agreement with the recommended values. 相似文献
69.
Summary Fifteen palladium(II) square-planar complexes containing monodentate and/or bidentate anti- and syn-furan-2-aldoxime (FDH) have been isolated and characterized by elemental analysis, molecular weight determination, conductance studies, magnetic moments and i.r. spectral studies. The monodentate ligand coordinates through the nitrogen atom while the bidentate ligand coordinates through the furan oxygen atom and the nitrogen atom. The C-O-C stretching frequency of the furan ring may be taken as the criterion for the denticity of this ligand and is observed at 1240 and 1270 cm– in anti- and syn-furan-2-aldoxime respectively. A shift to lower frequency occurs (in the complex) if the ligand is bidentate, however this frequency is unaffected if the ligand is monodentate. 相似文献
70.
A simple and sensitive method for the determination of isoproturon, a widely used herbicide is described here which is based on alkaline hydrolysis of isoproturon to its corresponding primary amine followed by diazotization and coupling with p-aminoacetophenone in alkaline medium. The absorption maxima of the coloured compound formed is measured at 525 nm. Beer's law is obeyed over the concentration range of 0.5-5.0 mug in a final solution volume of 25 ml (0.02-0.2 ppm). The molar absorptivity and Sandell's sensitivity were found to be 8.6x10(5) l mol(-1) cm(-1) and 0.0002 mug cm(-2), respectively. The method has been satisfactorily applied to the determination of isoproturon in environmental and biological samples. 相似文献