Determination of Silver in Aluminum by Thin Layer Chromatography

Small quantities of silver in technical aluminum can be determined by TLC on the layer of microcrystalline cellulose after separation and concentration by coprecipitation with CdS. The chromatograms were developed by a solvent composed of butanol- methanol-water-nitric acid in the proportion 80 : 5 : 10 : 5 (v/v). Visualisation was made with hydrogen sulfide. After scanning the obtained spots, concentration of silver in the samples was calculated by comparison with reference spots

A Discussion of the Absorption Spectra of Substituted 4-Pyridones and Their 4-Thio Analogues

The absorption spectra of 3-hydroxy-1-aryl-4-pyridones, 2-carbethoxy- 5-hydroxy-1-aryl-4-pyridones and their 4-thio analogues are reported . The thio compounds exhibit a red shift in the characteristic long wavelength maximum, which can be explained with the help of the inductive effect when oxygen is replaced by sulphur. Similarly, with the help of the first-order inductive effect, a red shift in the bands is discussed . This shift is produced by the substitution of a carbethoxy group at position 2 of the pyridone ring (the charge distributions in the ring are calculated from Hilckel molecular orbitals). Finally, a red shift produced by substitution onto the nitrogen in the ring is examined with the help of the mesomeric effect

Circular Dichroism of Optically Active 1,4-Benzodiazepines

Assignment of the CD-bands of 1,4-benzodiazepin-2-one derivatives (1-14, 26), and their 2-deoxo-congeners (15-25) has been performed by applying the qualitative MO theory and the exc1iton coupling theory. It has been found that the longest wavelength band (about 310 nm), as well as that around 250 nm correspond to the B2u and B1u transition of the chiral partial chromophore A, respectively, while the corresponding transitions for the partial chromophore C give rise to the bands at 285 nm and 250 nm (Figures 2-4). The CD-signs for several of these Cotton effects can be derived in a nonempirical manner. 7-Nitro derivatives, 23-25 scape above analysis, however, since the nitro-group is a very strong perturber, which has its own absorption bands in the same region. Model cyclic and acyclic compounds 27-36 have been prepared, and their CD-spectra analysed in the same way

Circular Dichroism of Optically Active 1,4-Benzodiazepines

Assignment of the CD-bands of 1,4-benzodiazepin-2-one derivatives (1-14, 26), and their 2-deoxo-congeners (15-25) has been performed by applying the qualitative MO theory and the exc1iton coupling theory. It has been found that the longest wavelength band (about 310 nm), as well as that around 250 nm correspond to the B2u and B1u transition of the chiral partial chromophore A, respectively, while the corresponding transitions for the partial chromophore C give rise to the bands at 285 nm and 250 nm (Figures 2-4). The CD-signs for several of these Cotton effects can be derived in a nonempirical manner. 7-Nitro derivatives, 23-25 scape above analysis, however, since the nitro-group is a very strong perturber, which has its own absorption bands in the same region. Model cyclic and acyclic compounds 27-36 have been prepared, and their CD-spectra analysed in the same way

Zur Kenntnis der 2-(2\u27-Furyl)-benzthiazole. Thioamide. V. Mitteilung

Es wird eine Reihe neuer, im Benzolkern substituierter 2-(2\u27- Furyl)-benzthiazole, die durch Oxydation der entsprechenden Thiobrenzschleimsaure-N-arylamide mit Kaliumferricyanid in guter Ausbeute gewonnen werden konnten, beschrieben. Fur Identifikationszwecke wurden die gut kristallisierenden Pikrate von 2-(2\u27-Furyl)-benzthiazol und seinen in vorliegender Arbeit beschriebenen Abkommlingen dargestellt

Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter

The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions

The politics of performance: transnationalism and its limits in former Yugoslav popular music, 1999–2004

This paper examines transnational relations between the Yugoslav successor states from the point of view of popular music, and demonstrates how transnational musical figures (such as Djordje Balaševi?, Mom?ilo Bajagi?-Bajaga and Ceca Ražnatovi?) are interpreted as symbolic reference points in national ethnopolitical discourse in the process of identity construction. Another symbolic function is served by Serbian turbofolk artists, who in Croatia serve as a cultural resource to distance oneself from a musical genre associated by many urban Croats with the ruralization (and Herzegovinization) of Croatian city space. In addition, value judgements associated with both Serbian and Croatian newly composed folk music provide an insight into the transnational negotiation of conflicting identities in the ex-Yugoslav context. Ultimately the paper shows how the ethnonational boundaries established by nationalizing ideologies created separate cultural spaces which themselves have been transnationalized after Yugoslavia's disintegration

A Discussion of the Absorption Spectra of Substituted 4-Pyridones and Their 4-Thio Analogues

The absorption spectra of 3-hydroxy-1-aryl-4-pyridones, 2-carbethoxy- 5-hydroxy-1-aryl-4-pyridones and their 4-thio analogues are reported . The thio compounds exhibit a red shift in the characteristic long wavelength maximum, which can be explained with the help of the inductive effect when oxygen is replaced by sulphur. Similarly, with the help of the first-order inductive effect, a red shift in the bands is discussed . This shift is produced by the substitution of a carbethoxy group at position 2 of the pyridone ring (the charge distributions in the ring are calculated from Hilckel molecular orbitals). Finally, a red shift produced by substitution onto the nitrogen in the ring is examined with the help of the mesomeric effect