Search results for " alchemy"
showing 6 items of 16 documents
Extreme overirradiance events in Norway: 1.6 suns measured close to 60°N
2015
Abstract We report the most extreme overirradiance event of 1.6 kW/m 2 measured so far in Grimstad, southern Norway (latitude 58°20′), at altitude of only about 60 m a.s.l. Images of the sky conditions taken with a wide-dynamic-range camera suggest that this is not the ultimate value for our location, but that extremes as high as 1.7 kW/m 2 may be possible. The phenomenon was caused by strong forward scattering of sunlight within 3° around the solar disk in thin, broken altocumulus clouds. The normalized spectrum of sunlight during such extreme events is very similar to the normalized clear-sky spectrum measured at Air Mass 1.4 and irradiance of 1.0 kW/m 2 . We suggest that the values excee…
Three Spirostanol Glycosides from the Seeds of Hyoscyamus Niger L.
2006
Three steroidal glycosides of spirostane series have been isolated from the seeds of Hyoscyamus niger L.(Solanaceae). Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods including one-dimensional, two-dimensional NMR and MS analysis. In the genus Hyoscyamus the given compounds have been found out for the first time.
GLYCOSIDES FROM LINARIA VULGARIS MILL
2008
A new flavonol glycoside, 5,4′-dimethylkaempferol 3-O-β-D-(6′′-α-Lrhamnopyranosyl) -glucopyranoside, together with three known compounds were isolated from the n-butanolic soluble fraction of underground and aerial parts of Linaria vulgaris Mill, collected on the territory of Moldova. The characterisation of these compounds was achieved by various chromatographic and spectroscopic methods (IR, UV, 13C-NMR, 1H-NMR and MS).
On Kekulé’s insight
2012
Ciència i literatura. Ja han acabat les guerres entre les dues cultures?
2014
Des que l’alquímia va començar a desafiar l’autoritat de l’Església, l’estatus del coneixement científic especialitzat i de l’alta cultura, sempre relatiu, ha estat molt qu?estionat. Durant segles, els escriptors, com a adalils de la cultura, han atacat les pretensions de la ciència ridiculitzant els seus practicants bé com a éssers malvats, obsessius i fins i tot alienats o bé com a ximples i ineptes inventors els experiments dels quals fallen irremissiblement. Discutirem exemples d’ambdós models en el seu context històric. A les acaballes del segle XX apareix un nou gènere, conegut com a «literatura de laboratori» (lab-lit). Els científics s’hi veuen retratats no segons els estereotips si…
Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry
2021
Radiation-sensitive gels are among the most recent and promising developments for radiation therapy (RT) dosimetry. RT dosimetry has the twofold goal of ensuring the quality of the treatment and the radiation protection of the patient. Benchmark dosimetry for acceptance testing and commissioning of RT systems is still based on ionization chambers. However, even the smallest chambers cannot resolve the steep dose gradients of up to 30–50% per mm generated with the most advanced techniques. While a multitude of systems based, e.g., on luminescence, silicon diodes and radiochromic materials have been developed, they do not allow the truly continuous 3D dose measurements offered by radiation-se…