Measurement of K X-ray intensity ratios in Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn employing carbon and nitrogen projectiles – VTT method

A method is suggested to effect the self absorption correction in a different way to estimate the K X-ray intensity ratios particularly when heavy ions are used as projectiles. Employing this method, the K_β/K_α intensity ratios are measured in some 3d shell elements by using Carbon and Nitrogen ions as exciting agents. The K_β/K_α intensity ratios thus obtained in the present work are compared with the intensity ratios due to some previous authors and also with Scofield theoretical values. Received 14 August 2000 and Received in final form 3 January 2001     

A study of solute-solvent interactions by conductance measurements

Proceedings - Mathematical Sciences - The interaction of a number of alkali, alkaline earth and transition element cations with solvents like triethyl phosphate, dimethyl sulphoxide and dimethyl...     

Conformation of the methyl group and tetrahydropyridine ring in N-acyltetrahydroquinaldine derivatives

NMR spectra of N-acyletrahydro quinaldines 12–19 and of pyridodibenzoxazepines 21–24 show the Me group to be axially oriented with the tetrahydropyridine ring in a half-boat conformation. The aroyl phenyl in both is twisted out of the CO plane. While the Me group again occupies the axial position in pyridophenanthridones 5 and 7 and pyridooxazinones 8 and 9, the tetrahydropyridine ring exists as a half-chair.     

Mean amplitudes of vibration: Pyramidal XYZ2 molecules

The theory of mean square amplitude of vibration using the symmetry co-ordinates has been applied to the pyramidal XYZ₂ molecular model. The elements of the mean square amplitude matrices and the mean amplitude quantities at 300° K. for thionyl halides have been reported.     

Analytical application of embelin

Summary Embelin is reported as a new reagent for gravimetric estimation of (1) uranium in pure solutions at p_H 6.0–6.5 and (2) thorium in acid solutions of 0.4 N HCl. In both cases, the precipitates were ignited and weighed as U₃O₈ and ThO₂. The separation of thorium from large excess of uranium and rare earths could also be effected employing this reagent. In addition, Cu, Cd, Ca, Ba, Sr, Al, Be, Mn, Mg and Zn do not interfere.     

Mean amplitudes of vibration: Some pyramidal XY3 and tetrahedral XY4 molecules

The theory of the determination of the mean amplitudes of vibration in molecules using the symmetry co-ordinates has been applied to the cases of arsenic halides belonging to the pyramidal XY₃ type and a few silicon and stannic halides of the tetrahedral XY₄ type. The mean square amplitudes and mean amplitudes of vibration have been evaluated at 298° K.     

Of heat capacity at homologous temperatures for metals showing h.c.p. ⇄ b.c.c. transformation

Some interesting aspects of the temperature dependence of the Planck’s functionφ and heat capacities of metals exhibiting the h.c.p. ⇄ b.c.c. transformation have been brought to light by the use of reduced temperature (T*) and Planck’s function (-φ T*). It has been shown that tangents drawn to the -φ T* vsT* plots of these metals at any chosen value ofT* intersect at a point whose coordinates are defined by the slope and intercept ofφ vs entropy plots at any homologous temperature and the selectedT* value. A generalized expression obtained for the temperature dependence ofφ has been used to demonstrate that the heat capacity of these metals may be visualized to have structural and material components.     

Silica-supported perchloric acid and potassium bisulfate as reusable green catalysts for nitration of aromatics under solvent-free microwave conditions

Silica-supported perchloric acid and bisulfate (SiO₂/HClO₄ and SiO₂/KHSO₄) have been developed as reusable green catalysts for nitration of aromatic compounds using NaNO₂ in acetonitrile medium under conventional and solvent-free microwave conditions. The reaction times under microwave irradiation are significantly shorter than conventional method even though the yields obtained in microwave-assisted reactions are comparable with those obtained under reflux conditions.     

Accessing π-expanded heterocyclics beyond dibenzothiophene: Syntheses and properties of phenanthrothiophenes

A series of phenanthrothiophenes are designed and synthesized from polyarylthiophenes through regioselective Scholl reactions in one step using iron chloride as catalyst. The molecular structures of these heteroarenes displayed multiple twisted fjords, which perturb the shapes of the polycyclic frameworks to pack in slipped to near-perfect face-to-face styles in parallel or antiparallel packings. Field-effect transistor devices using single crystals of 6,12-difluorodiphenanthro[9, 10-b:9′, 10′]thiophene gave a hole mobility of 0.22 cm² V⁻¹ s⁻¹.