Search Results

You are looking at 71 - 80 of 398 items for :

  • All content x
Clear All

Abstract  

Thermal behaviour of a number of organomercury(II) complexes of the type, p-XC6H4HgCl(L1) (I), p-XC6H4HgCl3(L2) (II), p-XC6H4HgL3 (III) and p-XC6H4HgL4 (IV) [L 1=isoniazid, L 2=theobromine, L 3=phenyldithiocarbamate, L 4=p-nitrophenyldithiocarbamate; X=Me, MeO, NO2] has been investigated. From TG curves, the order and activation energy of the thermal decomposition reaction have been elucidated. The variation of the activation energy has been correlated with the nature of the substituent on the phenyl ring. The heat of reaction has been elucidated from DSC or DTA studies. The fragmentation pattern has been analysed on the basis of mass spectra.

Restricted access

Summary This paper studies annihilating properties of operators generated by spherical convolution over the unit sphere O2q of Cq. Its specific aim is to answer the following question: given a complex number ?, |?|=1, to determine what functions of L 2(O2q) have zero average over every section  Ow ?,q  :={ z ?O2q: <z,w> = ?} of O2q . Here, <.,.>stands for the usual inner product of Cq.

Restricted access

Abstract

The adducts [CdX2(L-L)], where X = Cl, Br, I; L-L = 2,2’-bipyridine (bipy) or 2,2′-bipyridine N,N′-dioxide (bipyNO) have been synthesized and characterized by melting points, elemental analysis, thermal analysis, and IR spectroscopy. From calorimetric studies in solution, the standard enthalpies of formation of the adducts and several thermochemical parameters were determined. The mean standard enthalpies of the cadmium-nitrogen and cadmium-oxygen bonds have been estimated.

Restricted access

Abstract

We consider the Dirichlet operator H t=−d 2/dx 2+q(x) on L 2([t,∞)), where q is a convex potential with q(x)→∞ as x→∞. We show that the eigenvalue gap Γ(t) of H t is monotone increasing as t increases from −∞ to ∞. We also show that Γ(t) is strictly increasing if q is not linear at infinity. An asymptotic estimate of Γ(t) for quadratic potentials is obtained.

Restricted access

Abstract  

Extraction of microamounts of barium by a nitrobenzene solution of ammonium dicarbollylcobaltate (NH4 +B-) in the presence of 15-crown-5(15C5,L) has been investigated. The equilibrium data have been explained assuming that the complexes NH4L+, NH4L2 + and BaL2 2+ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

Restricted access

Abstract  

The complexes of the general formula MLSCN (M=Cu(I), Ag(I), L=2,2′-bipyridine=2-bipy, 4,4′-bipyridine=4-bipy or 2,4′-bipyridine=2,4′bipy) have been prepared and their IR spectra examined. The nature of metal-ligand coordination is discussed. Thermal decomposition in air of these complexes occurred in several successive endothermic and exothermic processes and the residue was Cu2O and Ag, respectively.

Restricted access

Abstract  

This paper deals with the investigation concerning the thermal stability of two new azo-derivatives and their Cu(II) complexes of type [Cu(L1)2] and, respectively, ((C4H9)4N)2[Cu(L2)2]. The thermal decomposition steps have been put in evidence. For the kinetically workable ones, the values of the activation energy vs. conversion degree were determined.

Restricted access

Abstract  

Solvent extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B) in the presence of dodecaethylene glycol (DDEG, L) has been investigated. The equilibrium data have been explained assuming that the species HL+, H2L2+, CsL+ and CsHL2+ (L = DDEG) are extracted into the organic phase. The values of extraction and stability constants of the complex species in nitrobenzene saturated with water have been determined.

Restricted access

Summary  

Extraction of microamounts of yttrium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of 15-crown-5 (15C5,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2, +, YL3+, YL2, 3+and YH-1L2, 2+are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

Restricted access

We investigate various aspects of stochastic integration in finite von Neumann algebras. For integration with respect to a bounded L 2 -martingale the idea of treating the integral as a bounded operator is developed. Several classes of integrable processes are defined, it turns out that some of them form a Banach or C *-algebra. We find representations of these algebras and establish relations between the von Neumann algebras generated by these representations. Finally, we characterize the range of the stochastic integration operator.

Restricted access