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31.
32.
A series of commercially available nanosized barium titanates has been investigated with respect to their use as high-k-ceramic
filler in polymer based composites with improved dielectric properties. The thermal treatment of the barium titanate powders
at 1,000°C causes a significant increase of the composite’s permittivity. X-ray diffraction experiments prior and after heat
treatment revealed that the barium titanate with smallest particle size and the largest specific surface area possesses the
thermodynamically unstable cubic phase. In case of the other investigated barium titanates the crystal lattice is distorted.
Thermal treatment induces the phase change into the tetragonal one and crystal lattice relaxation enabling higher permittivity
values. Composites with a solid load around 78 wt% with a bimodal particle size distribution show high permittivities around
50 and a low loss factor around 5‰ suitable for the realization of embedded capacitors via screen printing or tape casting. 相似文献
33.
Recently it has been found that very small amounts (a few 100 ppm) of Padded to -titanium aluminide can significantly alter the oxidationbehavior between 973 and 1273 K. The mechanism responsible for this changeis, however, still not clear. In the present study, phosphorus wasincorporated into the surface of TiAl (containing 50 at.% Al) by ionimplantation and oxidation tests were carried out at 1173 K inair. Improvement of oxidation resistance is only temporary up to 100 hr forphosphorus-implanted TiAl. After 100 hr, the oxidation rate increases andbreakaway oxidation follows. XRD and EPMA showed that the breakawayoxidation is connected with massive nitride formation. Two different modelsare proposed which can explain the effect of phosphorus additions on theoxidation kinetics of TiAl during the protective stage within the first100 hr. The breakaway effect can be explained by penetration of air to themetal–oxide interface zone because of microcrack formation in theoxide scale, which was experimentally proved by acoustic-emission analysis. 相似文献
34.
The class of "almost stabilizability subspaces" is introduced as the state-space analog of the class of stable, but not necessarily proper, transfer functions. Almost stabilizability subspaces can be considered as candidate closed-loop eigenspaces associated with infinitely fast and stable modes. We derive the basic properties of these subspaces, and show that they can be approximated by regular stabilizability subspaces. The relation with high gain feedback is elaborated upon in a number of applications. 相似文献
35.
PD Barnes G Diebold G Franklin B Quinn R Schumacher J Seydoux V Zeps P Birien W Dutty H Fischer J Franz E R?ssle H Schledermann H Schmitt R Todenhagen W Breunlich N N?gele R Br?ders Rv Frankenberg K Kilian W Oelert K R?hrich K Sachs T Sefzick G Sehl M Ziolkowski RA Eisenstein D Hertzog R Tayloe H Dennert W Eyrich R Geyer J Hauffe A Hofmann M Kirsch RA Kraft F Stinzing N Hamann T Johansson S Ohlsson 《Canadian Metallurgical Quarterly》1996,54(4):1877-1886
36.
Photoconductive detectors with rise times less than 10 ps have been made from GaAs grown by laser-stimulated MOCVD. The growth temperature was 450°C, and laser pulse energy and pulse repetition frequency were 120 mJ and 10 Hz, respectively. 相似文献
37.
In a total of 36 male rats, lesions of the cerebellar fastigial nucleus, but not lateral nuclear lesions or cerebellar cortical lesions, resulted in significant reductions in activity, open-field exploratory behavior, and social interactions. These deficits showed no recovery over a 4-wk testing period and were not related to the motor effects of the lesions. Other motivated behaviors (e.g., eating, grooming, gnawing, and pain responsiveness) were minimally affected. Results suggest the existence of 2 separate fastigial output pathways to neurobehavioral substrates: (a) the direct fastigio-bulbar pathway, which mediates the eating, grooming, and gnawing behaviors elicited by fastigial stimulation, and (b) the ascending fastigial projection to limbic structures, which may mediate fastigial influences on activity and social interaction. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
38.
39.
Bülter T Schumacher T Namdjou DJ Gutiérrez Gallego R Clausen H Elling L 《Chembiochem : a European journal of chemical biology》2001,2(12):884-894
The enzymatic oxidation of uridine 5'-diphospho-alpha-D-galactose (UDP-Gal) and uridine 5'-diphospho-N-acetyl-alpha-D-galactosamine (UDP-GalNAc) with galactose oxidase was combined with a chemical biotinylation step involving biotin-epsilon-amidocaproylhydrazide in a one-pot synthesis. The novel nucleotide sugar derivatives uridine 5'-diphospho-6-biotin-epsilon-amidocaproylhydrazino-alpha-D-galactose (UDP-6-biotinyl-Gal) and uridine 5'-diphospho-6-biotin-epsilon-amidocaproylhydrazino-N-acetyl-alpha-D-galactosamine (UDP-6-biotinyl-GalNAc) were synthesized on a 100-mg scale and characterized by mass spectrometry (fast atom bombardment and matrix-assisted laser desorption/ionization time of flight) and one/two dimensional NMR spectroscopy. It could be demonstrated for the first time, by use of UDP-6-biotinyl-Gal as a donor substrate, that the human recombinant galactosyltransferases beta3Gal-T5, beta4Gal-T1, and beta4Gal-T4 mediate biotinylation of the neoglycoconjugate bovine serum albumin-p-aminophenyl N-acetyl-beta-D-glucosaminide (BSA-(GlcNAc)17) and ovalbumin. The detection of the biotin tag transferred by beta3Gal-T5 onto BSA-(GlcNAc)17 with streptavidin-enzyme conjugates gave detection limits of 150 pmol of tagged GlcNAc in a Western blot analysis and 1 pmol of tagged GlcNAc in a microtiter plate assay. The degree of Gal-biotin tag transfer onto agalactosylated hybrid N-glycans present at the single glycosylation site of ovalbumin was dependent on the Gal-T used (either beta3Gal-T5, beta4Gal-T4, or beta4Gal-T1), which indicates that the acceptor specificity may direct the transfer of the Gal-biotin tag. The potential of this biotinylated UDP-Gal as a novel donor substrate for human galactosyltransferases lies in the targeting of distinct acceptor structures, for example, under-galactosylated glycoconjugates, which are related to diseases, or in the quality control of glycosylation of recombinant and native glycoproteins. 相似文献
40.
Schick C. Weiss H. Hernandez-Guillen F. Trasser A. Schumacher H. 《Electronics letters》2005,41(20):1116-1118
An ultra-compact 0.36 mm/sup 2/ differential wideband amplifier fabricated using SiGe technology is presented. Measurements show an on-wafer gain of 20.8 dB and a 3 dB cutoff frequency of 32.0 GHz. The mounted amplifier's gain is 19.5 dB. The circuit is intended to operate as a predriver in a 40 Gbit/s fibre-optic communication system. 相似文献