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61.
R. K. Bayer 《Colloid and polymer science》1991,269(5):421-432
Melt-spinning experiments were carried out at high quenching rates. Mechanical properties (elongation at break, natural draw ratio, and elastic recovery) have been measured. Significant variations of these quantities were observed when extrusion conditions were changed. This has been attributed to different states of the entanglements within the melt, which are directly transferred into the solid state. This intercorrelation between melt and solid-state properties has been substantiated in the case of rapidly cooled samples, where a poor crystallization on one side and a simultaneous good conservation of melt history on the other side are provoked. 相似文献
62.
J. Leppert S. Peudenier E. Bayer B. C. Grabmaier G. Blasse 《Applied Physics A: Materials Science & Processing》1994,59(1):69-72
The preparation of GdVO4:Bi3+ ceramics is indicated. Bismuth shows a strong tendency to evaporate during the sintering process. Time-resolved emission spectroscopy shows for sufficiently low Bi3+ concentrations subsequently: blue VO
4
3–
emission with a decay time corresponding to the transfer rate (106 s–1), yellow VO
4
3–
–Bi3+ emission, rare-earth impurity emission and VO
4
3–
–Bi3+ afterglow. 相似文献
63.
Clostridium thermocellum, an anaerobic thermophilic cellulolytic bacterium, produces an extremely cohesive, very high-molecular-mass multicellulase-containing complex termed thecellulosome. One of its components, the S1 subunit, is a nonenzymatic, 210 kDa glycopolypeptide. Upon preconditioning of the intact cellulosome with lowionic-strength or low-pH solutions, the S1 subunit separates in hot sodium dodecyl sulfate (SDS) solutions into a series of defined lowermolecular-mass subcomponents. Under the same conditions, the purified S1 subunit demonstrated the same behavior. Higher levels of glycosylation associated with the larger S1 subcomponents. The data support alterations in the conformational state of the S1 structure that lead to its disintegration induced by combined treatments with SDS and heating. Evidence is provided that this phenomenon may reflect a physiological response of the cellulosome, since similar alterations in S1 appear to accompany its binding to cellulose. 相似文献
64.
65.
B. Buszewski M. Hummel E. Bayer J. Geiger K. Schierbaum W. G?pel 《Fresenius' Journal of Analytical Chemistry》1990,336(5):403-408
Summary Two different types of porous glass (PG) were submitted to a thermal treatment in a temperature range from 620°C–700°C for 2 to 100 h. The materials thereby obtained have been characterized by static Secondary Ion Mass Spectrometry (SIMS). Special attention was paid to the change of the boron surface concentration. In addition we studied the specific surface area (SBET) dependence on the thermal treatment parameters, such as heating time and heating temperature. Selected PG materials have been modified with organosilanes and characterized prior to their use as packings in RP-HPLC.Dedicated to B. B.'s parents on their 60th birthday 相似文献
66.
E. Bayer 《Fresenius' Journal of Analytical Chemistry》1989,333(7):730
67.
D. Reuter V. Stavarache A.D. Wieck M. Schwab R. Oulton M. Bayer 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):73
We have performed single dot photoluminescence and time-resolved ensemble photoluminescence measurements on InAs quantum dots embedded in a lateral in-plane p–i–n or n–i–n device, respectively, which makes the application of lateral electric fields, i.e. field direction perpendicular to the growth direction, feasible. Time-resolved measurements show an increase in the radiative lifetime of up to 30% with increasing field. We attribute this to the reduced overlap between the electron and hole wave functions. Single dot spectroscopy revealed a small red-shift of the emission energies of maximum 0.5 meV. This shift can be explained by the quantum confined Stark effect taking into account that the red-shift due to the band-tilting is partly compensated by a decrease in exciton binding energy. 相似文献
68.
69.
G. Guttroff M. Bayer A. Forchel D. V. Kazantsev M. K. Zundel K. Eberl 《JETP Letters》1997,66(7):528-533
We study InP quantum dots which are prepared by strain induced self-assembly on GaAs substrates with a GaInP buffer layer
using a near field scanning optical microscope operating at near liquid He bath temperatures in the collection mode. Single
quantum dots are identified spatially and spectrally due to their photoluminescence spectrum. Series of luminescence lines
due to single dots of different sizes are discussed in terms of dot height and width fluctuations.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 7, 497–501 (10 October 1997) 相似文献
70.