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Kaster Jeffrey A. Michelsen Donald L. Velander William H. 《Applied biochemistry and biotechnology》1990,(1):469-484
A microbubble dispersion (MBD) was used to supply oxygen for aerobic fermentations in a standard 2 L stirred tank fermenter.
The microbubble dispersion was formed using only surfactants produced naturally. Growth rates ofSaccharomyces cerevisiae cultures were found to be equal or greater with MBD sparging than with gas sparging. The oxygen transfer coefficent with
MBD sparging was found to be 190/h and independent of impeller speed from 100–580 rpm. The oxygen transfer coefficient with
air sparging rose from 55 to 132/h over the same range of impeller speeds. Power requirements for the fermenter systems were
estimated. 相似文献
2.
The development of a new variant of the Friedel-Crafts reaction that yields 3-aryl enol triflates is described. The reaction is practical, is atom-economical, and works well with electron-rich arene substrates. [reaction: see text]. 相似文献
3.
B. Hinkov F. Fuchs Q. K. Yang J. M. Kaster W. Bronner R. Aidam K. K?hler J. Wagner 《Applied physics. B, Lasers and optics》2010,100(2):253-260
We present the time-resolved spectral analysis of the settling process in a pulsed external-cavity quantum-cascade laser (EC-QC
laser) emitting in the wavelength range around 7.4 μm. Due to mode competition between the two cavities formed by the laser-chip
on one hand and the external-cavity on the other hand, a time-dependent spectral emission on a ns time-scale can be observed.
Depending on the spectral characteristic of the external cavity with respect to the chip gain curve time-delays of the external
cavity emission of 15–35 ns within the 100 ns drive pulse can be observed. 相似文献
4.
Krista M. Kaster Aksel Hiorth Grethe Kjeilen-Eilertsen Kate Boccadoro Arild Lohne Harald Berland Arne Stavland Odd Gunnar Brakstad 《Transport in Porous Media》2012,91(1):59-79
Microbial enhanced oil recovery (MEOR) represents a possible cost-effective tertiary oil recovery method. Although the idea
of MEOR has been around for more than 75 years, even now little is known of the mechanisms involved. In this study, Draugen
and Ekofisk enrichment cultures, along with Pseudomonas spp. were utilized to study the selected MEOR mechanisms. Substrates which could potentially stimulate the microorganisms
were examined, and l-fructose, d-galacturonic acid, turnose, pyruvic acid and pyruvic acid methyl ester were found to be the best utilized by the Ekofisk
fermentative enrichment culture. Modelling results indicated that a mechanism likely to be important for enhanced oil recovery
is biofilm formation, as it required a lower in situ cell concentration compared with some of the other MEOR mechanisms. The
bacterial cells themselves were found to play an important role in the formation of emulsions. Bulk coreflood and flow cell
experiments were performed to examine MEOR mechanisms, and microbial growth was found to lead to possible alterations in wettability.
This was observed as a change in wettability from oil wet (contact angle 154°) to water wet (0°) due to the formation of biofilms
on the polycarbonate coupons. 相似文献
5.
Bernhardt B Ozawa A Vernaleken A Pupeza I Kaster J Kobayashi Y Holzwarth R Fill E Krausz F Hänsch TW Udem T 《Optics letters》2012,37(4):503-505
We present the first (to our best knowledge) femtosecond enhancement cavity in the visible wavelength range for ultraviolet frequency comb generation. The cavity is seeded at 518 nm by a frequency-doubled Yb fiber laser and operates at a peak intensity of 1.2×10(13) W/cm(2). High harmonics of up to the ninth order (~57 nm) are generated in an intracavity xenon gas jet. Intracavity high harmonic powers of several milliwatts for the third harmonic order and microwatts for the fifth harmonic order prove the potential of the "green cavity" as an efficient ultraviolet frequency comb source for future spectroscopic experiments. A limiting degradation effect of the cavity mirrors is avoided by operating at a constant oxygen background pressure. 相似文献
6.
Ronald E. Hackler Kenneth W. Burow Sylvester V. Kaster David I. Wickiser 《Journal of heterocyclic chemistry》1989,26(6):1575-1578
A general synthesis of 3-amino-3-alkylpropenenitriles is described. These intermediates are further transformed to 5-amino-3-alkylisothiazoles. Also described is the synthesis of the novel isomer, 3-amino-5-t-butyl-isothiazole. 相似文献
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