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101.
102.
Underpotential deposition studies of copper on glassy carbon 总被引:1,自引:0,他引:1
Studies on the deposition and dissolution of copper from 0·5 M sulphuric acid solutions onto glassy carbon (GC) using potential
sweep techniques indicated that an additional peak occurs at higher positive potentials than the bulk stripping peak. This
peak is identified as due to the stripping of underpotential deposited (UPD) copper. Results of investigations on the effect
of sweep rate, deposition potential and time of deposition on the peak characteristics of UPD and bulk deposited copper are
also reported. 相似文献
103.
Summary The mixed ligand complex, [Fe(Phen)2(N3)2] can be extracted into nitrobenzene giving a molar absorptivity of 16750 at 510 nm. This is the basis of a photometric method for iron which may be either in the trivalent or bivalent state. The new method is free from interference from a number of substances and is more sensitive than the ferroin method.
Zusammenfassung Der Eisen-Phenanthrolin-Azid-Mischkomplex [Fe(Phen)2(N3)2] ist mit Nitrobenzol extrahierbar und gibt bei 510 nm eine molare Absorption von 16750. Darauf läßt sich eine photometrische Bestimmungsmethode für zweioder dreiwertiges Eisen begründen. Diese wird von vielen Stoffen nicht gestört und ist empfindlicher als die Ferroinmethode.相似文献
104.
S. K. Singh K. M. Parida B. C. Mohanty S. B. Rao 《Reaction Kinetics and Catalysis Letters》1995,54(1):29-34
Ultrafine -SiC with high surface area (150 m2 g–1) has been synthesized by inflight processing of charred rice husk in a r.f. plasma reactor operating at atmospheric pressure. The plasma-synthesized particles were doped with platinum (1%) and tested as a catalytic support material. The catalyst (1% Pt doped -SiC) showed 100% conversion of CO to CO2 at a temperature as low as 175°C. 相似文献
105.
M. Wei X. Y. Xu J. He G. Y. Rao H. L. Yang 《Journal of Thermal Analysis and Calorimetry》2006,85(3):795-800
Supramolecular 2,3- and 2,5-pyridinedicarboxylate (PDC) intercalated
ZnAl-layered double hydroxides (2,3- and 2,5-PDC–ZnAl–LDHs) have
been prepared by ion exchange method. The structure and composition of the
intercalated materials have been studied by X-ray diffraction (XRD) and inductively
coupled plasma emission spectroscopy (ICP). The study indicates that the 2,3-PDC
and 2,5-PDC anions are accommodated as interdigitated bilayer and monolayer
arrangement respectively between the sheets of LDHs. Furthermore, their thermal
decomposition processes were studied by the use of in situ high temperature
X-ray diffraction (HT-XRD), and the combined technique of thermogravimetry-differential
thermal analysis-mass spectrometry (TG-DTA-MS) under N2 atmosphere. Based
on the comparison study on the temperatures of both decarboxylation and complete
decomposition of interlayer PDC, it can be concluded that 2,5-PDC–ZnAl–LDHs
has higher thermal stability than that of 2,3-PDC–ZnAl–LDHs. 相似文献
106.
Some new metal-containing polyurethanes were synthesized from manganese and lead salts of mono(hydroxyethyl)phthalate by condensing them with hexamethylene diisocyanate and toluene diisocyanate in dimethylformamide as solvent. The polymers were characterized by viscometry, infrared spectroscopy and thermal analysis. The decomposition temperatures of these polymers were found to be significantly lower than those of metal-free polymers of similar structure. However, the rates of decomposition of metal-containing polyurethanes were lower than those of polyurethanes having no metal. Inherent viscosities in DMSO at 30° of these polyurethanes were low, ranging from 0.043 to 0.067. 相似文献
107.
A new method has been developed for the direct titrimetric determination of manganeseII, depending on its oxidation to manganeseIII with potassium dichromate at room temperature in a strong phosphoric acid medium using a potentiometric or photometric endpoint. Oxygen of the air does not interfere. The potentiometric method gives results to an accuracy within ± 0.3% for 20–150 mg of manganese/50 ml of titration solution; with the photometric method 5–17 mg of manganese/40 ml of titration solution can be determined with an error of 0.3–1.0% depending on the amount present. Potassium dichromate in 12.0M phosphoric acid has a formal redox potential of about 1.5 V and this reagent appears to have great possibilities in titrimetric analysis. 相似文献
108.
The L3/L2 white-line intensity ratio in transition-metal oxides deviates widely from the statistical value of 2 : 1 but shows interesting systematics. In a series of oxides of a given metal, the ratio reaches a maximum for the d5 configuration (e.g. MnO) and a minimum for the d0 configuration (e.g. KMnO4). In a series of monoxides, sesquioxides and dioxides of different metals, the ratio is again a maximum at the d5 configuration and decreases as the configuration changes towards d0 or d10. Our results, obtained by electron energy-loss spectroscopy, carried out in an electron microscope, are interpreted on an atomic mechanism involving spin-spin coupling. According to this model, the L2 transition probability decreases in the progression d0 to d5 whereas the L3 transition probability decreases beyond d5. 相似文献
109.
Venkatapuram Padmavathi Pinnu Thriveni Boggu Jagan Mohan Reddy Adivireddy Padmaja 《Journal of heterocyclic chemistry》2005,42(1):113-116
A new class of five membered heterocycles, thiadiazoles, triazoles and oxadiazoles were prepared from sulfonyl acetic acids via acid hydrazides. 相似文献
110.
Experimental conditions have been established for the accurate direct titrimetric determination of arsenic(III) with potassium dichromate, using ferroin and N-pnenylanthranilic acid as redox indicators. Interferences have been considered. 相似文献