Derivativspektrophotometrie höherer Ordnung zur Feinauflösung von UV/VIS-Spektren

Talsky, Gerhard; Mayring, L.; Kreuzer, H. J.

doi:10.1002/ange.19780900725

Cited by 18 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More information can be gained by the calculation of the second derivative of the spectra as shown in Figure b. Forming of the second derivative is used as a mathematical tool for the separation of strongly overlapping signals . The second derivative resolves an additional signal at approximately 716 cm -1 which is due to a second crystal polymorph.…”

Section: Results and Initial Discussionmentioning

confidence: 99%

Analysis of the Degree of Reversibility of Crystallization and Melting in Poly(ethylene-co-1-octene)

2000

View full text Add to dashboard Cite

The degree of reversibility of crystallization and melting of poly(ethylene-co-1-octene) containing 7.3 mol % (24 mass %) of 1-octene was measured with temperature-modulated differential scanning calorimetry. The sample was crystallized at different cooling rates after excluding self-nuclei of the crystals. The sample was also examined by X-ray scattering techniques, infrared spectroscopy, and standard differential scanning calorimetry. The cooling rates ranged from 0.1 K min -1 to quick quenching. The low-temperature enthalpy remained constant in all cases, by increasingly creating a pseudohexagonal crystallinity of lower heat of fusion instead of a smaller amount of orthorhombic crystals. The crystallization during cooling from the nonseeded melt is characterized by a steplike crystal growth, a characteristic not seen on slow, seeded, crystallization. The initial growth is followed by a continuous increase of the crystallinity down to the glass transition. The onset of crystallization shifts to lower temperatures with increasing cooling rates. With increasing cooling rate, the perfection and the size of the initially formed crystals decrease. On slow crystallization orthorhombic crystals grow; on fast crystallization, these are increasingly replaced by the less-ordered, pseudohexagonal crystals. These changes are paralleled by a systematic increase of the reversible crystallization and melting by about 10% when increasing the cooling rate from 1 to 10 K min -1 . For the first time these surprising observations have been discussed on the basis of structural information.

show abstract

Section: Results and Initial Discussionmentioning

confidence: 99%

Analysis of the Degree of Reversibility of Crystallization and Melting in Poly(ethylene-co-1-octene)

2000

View full text Add to dashboard Cite

show abstract

“…The normalized absorbance is thickness‐invariant, which we checked by preparation and investigation of additional sets of samples of different initial thicknesses before drawing. The development of the pseudohexagonal structure on cold‐drawing/relaxation was followed by the absorbance at 717 cm −1 ,44, 45 which is qualitatively estimated by the second derivative of the absorbance versus wave number of the thickness‐corrected spectra 46, 47…”

Section: Methodsmentioning

confidence: 99%

Directional atherectomy of a calcified lesion using a new atherectomy device

Reimers

Stanković

Prati

et al. 2002

Cathet Cardio Intervent

View full text Add to dashboard Cite

show abstract

“…A description of an automated analyzer for the colorimeter determination of vinyl acetate [281] 587 estrogens drugs sodium hexanitritocobaltate(III) (CHC13) [366] 296 furfural o-aminophenol, Zn acetate [425] filter has been used with an ultraviolet-visible spectrometer to obtain good quality derivative spectra (139). Several analog devices have been developed to obtain derivative spectra up to 7th order (568,569). A microcomputer controlled monochromator accessory module has been developed which provides split-beam dual-wavelength capability as well as ratiometric compensation for source fluctuation at a single wavelength (112).…”

Section: Physicsmentioning

confidence: 99%