Use of thin collodion films to prevent recoil-ion contamination of alpha-spectrometry detectors

Recoil ions from alpha-particle emission can contaminate surface-barrier detection systems. This contamination results in increased measurement uncertainty, and may require the replacement of expensive detectors. Disposable thin Collodion films are easily prepared and effectively retard the recoil ions when either directly applied to the surface of alpha-sources or as catcher foils between the source and the detector. The thin films are particularly effective for relatively low-level sources, but can sustain structural damage when exposed to high levels of recoil ions (tens of thousands per second) over extended periods of time.     

Existence Result for Triangular Reaction—Diffusion Systems with L1 Data and Critical Growth with Respect to the Gradient

In this paper we prove the existence of weak solutions for m × m reaction-diffusion systems for which two main properties hold: the positivity of the solutions and the triangular structure. Moreover, the nonlinear terms have critical growth with respect to the gradient.     

Electronic, infrared, and Raman spectral studies of the reaction of iodine with 4-aminopyridine

The reaction of iodine as an electron acceptor with the base 4-aminopyridine (4APY) has been investigated spectrophotometrically in chloroform at room temperature. The electronic absorptions, infrared and Raman spectra, photometric titration as well as elemental analysis of the obtained iodine complex indicate the formation of the pentaiodide charge-transfer complex with the general formula [(4APY)(2)](+)I(5)(-). The characteristic strong absorptions of I(5)(-) are observed around 380 and 295 nm. Far infrared and Raman spectra of the solid complex show the vibrations of the linear I(5)(-) ion with D(infinityh) symmetry at 154, 104 and 89 cm(-1) assigned to nu(s)(I--I), outer bonds, nu(s)(I--I), inner bonds and nu(as)(I--I) inner bonds, respectively.     

Spectroscopic investigation of the novel charge-transfer complex [(phen)(TCNE)(12)] formed in the reaction of phenacetin with tetracyanoethylene

The charge-transfer (CT) interaction of the electron donor phenacetin (phen) and the pi-electron acceptor tetracyanoethylene (TCNE) has been studied in CH(2)Cl(2). The results obtained indicate the formation of the novel CT-complex with the general formula [(phen)(TCNE)(12)]. The 1:12 stoichiometry of the reaction was based on photometric titration, elemental analysis, infrared, thermal and cyclic voltametry measurements of the formed CT-complex.     

Synthesis and Vibrational Studies of Oxovanadium (IV) - Tetradentate Schiff Base Complexes

The two new Schiff base complexes of oxovanadium (IV) [VO(acac-en)] (acac-en = bisacetylactone-ethylenediimino) and [VO(sal-o-phdn)] (sal-o-phdn = N,N′-o-phenylenebis (salicylideneiminato) have been prepared. The infrared spectra of the solid complexes have been obtained and assigned on the bases of C_s symmetry. A polymeric chain structure with V-O-V bridge has been adopted for the both complexes.     

Amineptine Plastic Membrane Electrode Based on its Ion Associate with Tetraphenylborate and Phosphomolybdic Acid

New amineptine hydrochloride (Am-Cl) ion-selective electrodes (conventional type) based on amineptinium-tetraphenylborate (I) and amineptinium-phosphomolybdate (II) were prepared. The electrodes exhibited mean slopes of calibration graphs of 57.9?mV and 53.8?mV per decade of (Am-Cl) concentration at 25?°C for electrodes (I) and (II), respectively. The electrodes can be used within the concentration range 3.16×10^?5?10^?2?M (Am-Cl) at a pH range of 2.0–3.9 for both electrodes. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficients of the electrodes, which were 0.00172?V?°C^?1 and 0.00091 V?°C^?1 for (I) and (II) electrodes, respectively. The electrodes showed a very good selectivity for (Am-Cl) with respect to a number of inorganic cations and sugars. The standard addition method is successfully applied to determine (Am-Cl) in pure solutions and in amineptine-containing tablets.