Indirect polarographic determination of stability constants

The stability constants of cadmium thiosulphate complexes have been determined in 25% methanol medium. The stability constants of thiosulphate complexes of zinc and lanthanum have been determined by the indirect method using cadmium as the indicator ion.     

Indirect polarographic determination of stability constants

Polarograms of cadmium at different concentrations of pyridine were taken in 0·5 M potassium nitrate medium. From a plot of the half-wave potentialvs. log (Py), the co-ordination numbers of the complexes were calculated to be one and two. The indirect method was applied to the study of cobalt complexes of pyridine. From the shift in the half-wave potentials of cadmium in the presence of cobalt, a plot of\(\bar n\) vs. pA was obtained which indicated the presence of higher complexes of cobalt and pyridine. The stability constants were calculated.     

Indirect polarographic determination of stability constants: Zinc complexes with glycollic acid

A study of the glycollate complexes of zinc using indium as the indicator ion gave results identical to that obtained with cadmium as the indicator ion. It appears that the reversible reduction of the indicator ion is not an essential prerequisite provided that the kinetic parameters for the reduction of the indicator ion remain the same in the absence and in the presence of the metal under study.     

The raman spectra of some metallic halides

Proceedings - Mathematical Sciences - The paper describes the results of the study of the Raman spectra of the halides of cadmium and zinc as well as of magnesium chloride, magnesium bromide and...     

Vanadometric estimation of germanium

Germanium is determined titrimetrically using sodium vanadate as the oxidant, after reducing Ge(IV) to Ge(II) by sodium hypophosphite. Germanium in presence of the associated elements like zinc, cadmium, arsenic and silver as well as in the synthetic mixture of germanium-cadmium sulphide has been estimated.     

Physico-chemical studies on the formation of some tungsto-tartrates and molybdo-tartrates

The viscosity, depression in freezing point, potentiometric and conductometric experiments on the reaction of tartaric acid with sodium tungstate and sodium molybdate indicated the formation of the complex at 1:1 ratio of tungstate or molybdate to tartaric acid. The complex compounds have been isolated. The silver, mercurous, copper, cadmium, zinc, mercuric, barium, strontium, lead, cobalt and nickel salts of tungstotartrate and molybdo-tartrate have been prepared from the sodium salt and their composition studied.     

Investigation of the electronic absorption spectra of some pyridine derivatives iodine complexes

The electronic absorption spectra of some pyridine derivativesiodine complexes are measured and discussed. The thermodynamic constants of these complexes are calculated. It is confirmed that the stability of the complex depends on the type as well as the position of the substituent on pyridine nucleus. A linear relationship is obtained between the enthalpies — ΔH and the shift of the blue iodine band Δv of the complexes. It is also found that as the Pi electron density on the nitrogen atom increases, the stability of the complex also increases.     

A polarographic study of methionine complexes of cadmium and indium

The stability constants of methionine complexes of cadmium were determined polarographically by ths method of DeFord and Hume as β₁ =6·5 × 10³, β₂ = 1·7 × 10⁶ and β₃ = 2·1 · 10⁸. The indium complexes were studied by the modified method of Momoki and Ogawa and two complexes, with β₁ = 1·7 × 10⁸ and β₂ = 8·4 × 10¹³, were identified in the concentration range studied. The haf-wave potential of uncomplexed indium ion which cannot be measured directly owing to the irreversible nature of the reduction was calculated as — 0·503 Vvs. SCE.     

Studies onO-Vanillinoxime as an analytical reagent

o-Vanillinoxime has now been used for the gravimetric determination of copper and nickel alone and in presence of many foreign ions. Copper can be estimated in presence of appreciable amounts of cadmium, zinc, cobalt and lead. The interference due to iron (III), antimony (III), bismuth (III) and tin (II) can be removed by suitable masking agents. Determination of copper and nickel in presence of each other has also been carried out.     

Amperometric determination of copper with resacetophenone-phenylhydrazone

An amperometric method for determination of copper (II) with resacetophenone-phenylhydrazone is described. The method is useful to determine the metal in amounts ranging from 1·0–16·0 mg with an accuracy of ±1 per cent. Ten-fold excess of zinc, cadmium and nickel did not interfere. Iron which interefered both polarographically and chemically was complexed with sodium fluoride and the determination was successfully carried out. The method was applied for the determination of the metal in german silver.     

Synergism in the extraction of cadmium

Synergism in the extraction of cadmium by mixtures of BFA and TOPO or TBP has been investigated. Extraction of cadmium was found negligible in the presence of BFA, TOPO or TBP alone while the addition of alkylphosphorus ester to the β-diketone resulted in considerable enhancement of the extraction. The nature of the adduct was found to be of the type [Gd (BFA)₂ (TOPO)₂] and the equilibrium constant for the reaction was also evaluated. Similar results were observed in the case of TBP, while DPSO did not enhance the extraction, indicating the donor strengths of the synergists to be in the order TOPO >TBP >DPSO. The coordination of alkylphosphate to the metal ion was confirmed by infrared spectra of the complexes in benzene.     

Backward shifts on function algebras

J.R. Holub (1988) [10] introduced the concept of backward shift on Banach spaces. We show that an infinite-dimensional function algebra does not admit a backward shift. Moreover, we define a backward quasi-shift as a weak type of a backward shift, and show that a function algebra A does not admit it, under the assumption that the Choquet boundary of A has at most finitely many isolated points.     

Spectral averaging for trace compatible operators

In this note the notions of trace compatible operators and infinitesimal spectral flow are introduced. We define the spectral shift function as the integral of infinitesimal spectral flow. It is proved that the spectral shift function thus defined is absolutely continuous and Kreĭn's formula is established. Some examples of trace compatible affine spaces of operators are given.

     

The Spectral Shift Function and the Friedel Sum Rule

We study the relationship between the spectral shift function and the excess charge in potential scattering theory. Although these quantities are closely related to each other, they have been often formulated in different settings so far. Here, we first give an alternative construction of the spectral shift function, and then we prove that the spectral shift function thus constructed yields the Friedel sum rule.     

Spectral Shift Function of the Schrödinger Operator in the Large Coupling Constant Limit

The spectral shift function of a Schrödinger operator with a perturbation of definite sign is considered. The asymptotics of the spectral shift function for large coupling constant is studied, and results concerning positive and negative perturbations are compared. A more general case of unperturbed operator given by a function of the Laplacian is discussed. This case explains the dependence of the asymptotics of the spectral shift function on the perturbation potential on the one hand and on the order of the unperturbed operator on the other hand.     

Cantor Diagrams: A Unifying Discussion of Self-Reference

Within the framework of category theory, Cantor diagrams are introduced as the common structure of the self-reference constructions by Cantor, Russell, Richard, Gödel, Péter, Turing, Kleene, Tarski, according to the so-called Cantor diagonal method. Such diagrams consist not only of diagonal arrows but also of idempotent, identity and shift arrows. Cantor theorem states that no Cantor diagram is commutative. From this theorem, all the constructions above can be systematically retrieved. We do this by grouping them into two main classes: the class based on Cantor diagrams with a numerical shift function and the class based on Cantor diagrams with a Boolean shift function.     

Finite and bounded Auslander-Reiten components in the derived category

We analyze Auslander-Reiten components for the bounded derived category of a finite-dimensional algebra. We classify derived categories whose Auslander-Reiten quiver has either a finite stable component or a stable component with finite Dynkin tree class or a bounded stable component. Their Auslander-Reiten quivers are determined. We also determine components that contain shift periodic complexes.     

On the polarography of zinc in ethylenediamine medium

Polarography of zinc in ethylenediamine medium has been carried out. The equilibrium potentials have been determined by amalgam polarography. The standard rate constant for the electrode reaction and the stability constants of the complexes have been calculated.     

On partial tilting modules and right bounded complexes

We construct rather short partial tilting complexes [(T)\dot]{\dot T} such that quite different indecomposable right bounded complexes [(C)\dot]{\dot C} have the property that any morphism from [(T)\dot]{\dot T} to a shift of [(C)\dot]{\dot C} is homotopic to zero. We also show that, for some [(T)\dot]{\dot T} , the strategy to obtain a bounded complex [(C)\dot]{\dot C} as a mutation of [(T)\dot]{\dot T} is not unique.     

Recovering the Geometry of a Flat Spacetime from Background Radiation

We consider globally hyperbolic flat spacetimes in 2 + 1 and 3 + 1 dimensions, in which a uniform light signal is emitted on the r-level surface of the cosmological time for r → 0. We show that the frequency shift of this signal, as perceived by a fixed observer, is a well-defined, bounded function which is generally not continuous. This defines a model with anisotropic background radiation that contains information about initial singularity of the spacetime. In dimension 2 + 1, we show that this observed frequency shift function is stable under suitable perturbations of the spacetime, and that, under certain conditions, it contains sufficient information to recover its geometry and topology. We compute an approximation of this frequency shift function for a few simple examples.