排序方式： 共有36条查询结果，搜索用时 15 毫秒
1.
2.
3.
Degradation and formation of refractory DOM by bacteria during simultaneous growth on labile substrates and persistent lake water constituents 总被引：3，自引：0，他引：3
Dr. Annette Geller 《Aquatic Sciences - Research Across Boundaries》1985,47(1):27-44
Changes in molecular size distribution associated with degradation of refractory DOM (macromolecules, apparent mol wt. ≥1500)
by 3 strains of bacteria were investigated by Sephadex G-15 gel permeation chromatography and DOC analysis of the eluates.
Macromolecules and bacteria were isolated from the same lake water sample, one taken in summer and one in winter. The decompositional
changes of the DOM fraction were compared with respect to substance- and bacterial species-specific differences, and with
respect to the action of photolysis and co-substrate supplementation. The metabolite patterns resulting from the simultaneous
growth of the bacteria on the persistent DOM fraction and the labile co-substrate, glutamic acid were analyzed. The macromolecules
differed in accessible components, and the bacteria degraded most effectively the DOM fraction of the parent lake water sample.
Photolysis was the prerequisite for the reduction of the inaccessible bulk of the macromolecules. Glutamic acid enhanced the
degradation of the macromolecules. The enhancement effect was impaired by the build up of waste products which balanced the
losses of the DOM fraction. Three formation modes of refractory metabolites could be distinguished: formation of intensely
UV absorbing small sized products which were poor in DOC during degredation of (1) the macromolecules of winter, and (2) of
glutamic acid, and formation of (3) apparent high molecular weight substances from glutamic acid in cultures containing the
macromolecules of summer which probably results from a stable linkage between the small sized metabolites of the amino acid
and the DOM fraction.
The research was supported by the Deutsche Forschungsgemeinschaft. 相似文献
4.
5.
6.
Echert D.C. Morison J.H. White G.B. Geller E.W. 《Oceanic Engineering, IEEE Journal of》1989,14(2):195-202
The development and initial field test results of the Autonomous Ocean Profiler (AOP) are described. The profiler uses a hydrodynamic lift device to fly the instrument package up and down the water column along a taut vertical cable. Because the local currents drive the platform's vertical motion, power requirements are low, and therefore long, unattached deployments are possible. By using ARGOS or GOES satellite retrieval networks, the system can supply near-real-time data. The system provides profile data at very high vertical resolution in contrast to conventional buoys, which gather data only at fixed sensor depths. Because only a single set of sensors is required to cover the vertical range desired, the system is low cost and, for many applications, expendable. The initial deployment configuration is as an Arctic drifting buoy 相似文献
7.
8.
Geller B. Capellano V. Brossier J.-M. Essebbar A. Jourdain G. 《Oceanic Engineering, IEEE Journal of》1996,21(2):150-155
This paper concerns the equalization problem of an underwater high rate transmission system. Because the channel delay spread of an horizontal link is large compared with the data duration, we have developed an adaptive equalizer in order to minimize the calculus burden of the moving receiver. The performance of this equalizer on synthetic and real channels is discussed 相似文献
9.
Earthquake prediction: a critical review 总被引：22，自引：0，他引：22
Robert J. Geller 《Geophysical Journal International》1997,131(3):425-450
Earthquake prediction research has been conducted for over 100 years with no obvious successes. Claims of breakthroughs have failed to withstand scrutiny. Extensive searches have failed to find reliable precursors. Theoretical work suggests that faulting is a non-linear process which is highly sensitive to unmeasurably fine details of the state of the Earth in a large volume, not just in the immediate vicinity of the hypocentre. Any small earthquake thus has some probability of cascading into a large event. Reliable issuing of alarms of imminent large earthquakes appears to be effectively impossible. 相似文献
10.