| Records |
| Author |
Aberle, N.; Witte, U. |
| Title |
Deep-sea macrofauna exposed to a simulated sedimentation event in the abyssal NE Atlantic: in situ pulse-chase experiments using 13C-labelled phytodetritus |
Type |
Journal Article |
| Year |
2003 |
Publication |
Marine Ecology Progress Series |
Abbreviated Journal |
Mar Ecol Prog Ser |
| Volume |
251 |
Issue |
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Pages |
37-47 |
| Keywords |
Deep-sea; Pulse-chase experiment; δ13C; Benthic carbon remineralisation; Macrofauna; Atlantic Ocean, Porcupine Abyssal Plain |
| Abstract |
Tracer experiments with 13C-labelled diatoms Thalassiosira rotula (Bacillariophycea, 98% 13C-labelled) were conducted at the Porcupine Abyssal Plain (PAP) in the NE Atlantic (BENGAL Station; 48<b0>50'N, 16<b0>30'W, 4850 m depth) during May/June 2000. In situ enrichment experiments were carried out using deep-sea benthic chamber landers: within the chambers a spring bloom was simulated and the fate of this food-pulse within the abyssal macrobenthic community was followed. In focus was the role of different macrofauna taxa and their vertical distribution within the sediment column in consuming and reworking the freshly deposited material. T. rotula is one of the most abundant pelagic diatoms in the NE Atlantic and therefore 0.2 g of freeze dried T. rotula, equivalent to 1 g algal C m-2 yr-1, was injected into each incubation chamber. Three different incubation times of 2.5, 8 and 23 d were chosen in order to follow the uptake of 13C-labelled phytodetritus by macrofauna. After only 2.5 d, 77% of all macrofauna organisms showed tracer uptake. After 23 d the highest degree of enrichment was measured and 95% of the individuals had taken up 13C from the introduced algal material. In addition to that a downward transport of organic matter was observed, even though the mixing was not very intense. The initial processing of carbon was dominated by polychaetes that made up a percentage of 52% of total macrofauna. In general macrofauna organisms that lived close to the sediment surface had higher access to the simulated food-pulse, confirming the hypothesis that individuals close to the sediment surface have the strongest impact on the decomposition of phytodetritus. In our study we observed only modest vertical entrainment of 13C tracers into the sediment. With regard to contradictory results from former 13C-enrichment experiments in bathyal regions, compared to results from our study site in the abyssal plain, we thus propose pronounced differences in feeding strategies between macrofauna communities from continental margins and abyssal plains. |
| Address |
Aberle, Witte: Max Planck Institute for Marine Microbiology, Celsiusstr. 1, 28359 Bremen, Germany; Aberle: Present address: Max Planck Institute for Limnology, August-Thienemann-Str. 2, 24306 Pl<f6>n, Germany; Email: aberle@mpil-ploen.mpg.de |
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Thesis |
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| Publisher |
Inter-Research |
Place of Publication |
Oldendorf/Luhe |
Editor |
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| Language |
English |
Summary Language |
English |
Original Title |
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Series Issue |
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Edition |
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| ISSN |
0171-8630 |
ISBN |
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Medium |
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Area  |
NE Atlantic |
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Conference |
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| Notes |
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Approved |
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| Call Number |
refbase @ user @ 706 |
Serial |
4 |
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| Author |
Hajenius, M.; Baselmans, J. J. A.; Gao, J. R.; Klapwijk, T. M.; de Korte, P. A. J.; Voronov, B.; Gol'tsman, G. |
| Title |
Low noise NbN superconducting hot electron bolometer mixers at 1.9 and 2.5 THz |
Type |
Journal Article |
| Year |
2004 |
Publication |
Supercond. Sci. Technol. |
Abbreviated Journal |
Supercond. Sci. Technol. |
| Volume |
17 |
Issue |
5 |
Pages |
S224-S228 |
| Keywords |
NbN HEB mixers |
| Abstract |
NbN phonon-cooled hot electron bolometer mixers (HEBs) have been realized with negligible contact resistance between the bolometer itself and the contact structure. Using a combination of in situ cleaning of the NbN film and the use of an additional superconducting interlayer of a 10 nm NbTiN layer between the Au of the contact structure and the NbN film superior noise temperatures have been obtained as low as 950 K at 2.5 THz and 750 K at 1.9 THz. Here we address in detail the DC characterization of these devices, the interface transparencies between the bolometers and the contacts and the consequences of these factors on the mixer performance. |
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Series Issue |
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Edition |
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| ISSN |
0953-2048 |
ISBN |
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| Notes |
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Approved |
no |
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Serial |
558 |
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| Author |
Финкель, М. И.; Масленников, С. Н.; Гольцман, Г. Н. |
| Title |
Концепция приёмного комплекса космического радиотелескопа «Миллиметрон» |
Type |
Journal Article |
| Year |
2007 |
Publication |
Известия высших учебных заведений. Радиофизика |
Abbreviated Journal |
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| Volume |
50 |
Issue |
10-11 |
Pages |
924-934 |
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| Language |
russian |
Summary Language |
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Original Title |
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no |
| Call Number |
RPLAB @ s @ mix_review_2007_rus |
Serial |
410 |
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| Author |
Finkel, M. I.; Maslennikov, S. N.; Gol'tsman, G. N. |
| Title |
The concept of the receiving complex for the “Millimetron” space radio telescope |
Type |
Journal Article |
| Year |
2007 |
Publication |
Radiophys. Quant. Electron. |
Abbreviated Journal |
Radiophys. Quant. Electron. |
| Volume |
50 |
Issue |
10-11 |
Pages |
837-846 |
| Keywords |
HEB, applications, Millimetron, VLBI |
| Abstract |
We consider the current status of research in the development of a submillimeter and far-infrared receiving instrument and propose promising solutions for the receivers of the spaceborne telescope “Millimetron,” which allow one to realize comprehensively the opportunities given by this international project administrated by the Astrospace Center of the P. N. Lebedev Physical Institute of the Russian Academy of Sciences. |
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| ISSN |
0033-8443 |
ISBN |
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Approved |
no |
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Serial |
411 |
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| Author |
Ryabchun, S. A.; Tretyakov, I. V.; Finkel, M. I.; Maslennikov, S. N.; Kaurova, N. S.; Seleznev, V. A.; Voronov, B. M.; Goltsman, G. N. |
| Title |
Fabrication and characterisation of NbN HEB mixers with in situ gold contacts |
Type |
Conference Article |
| Year |
2008 |
Publication |
Proc. 19th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 19th Int. Symp. Space Terahertz Technol. |
| Volume |
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Issue |
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Pages |
62-67 |
| Keywords |
HEB, mixer, NbN, in-situ contacts |
| Abstract |
We present our recent results of the fabrication and testing of NbN hot-electron bolometer mixers with in situ gold contacts. An intermediate frequency bandwidth of about 6 GHz has been measured for the mixers made of a 3.5-nm NbN film on a plane Si substrate with in situ gold contacts, compared to 3.5 GHz for devices made of the same film with ex situ gold contacts. The increase in the intermediate frequency bandwidth is attributed to additional diffusion cooling through the improved contacts, which is further supported by the its dependence on the bridge length: intermediate frequency bandwidths of 3.5 GHz and 6 GHz have been measured for devices with lengths of 0.35 μm and 0.16 μm respectively at a local oscillator frequency of 300 GHz near the superconducting transition. At a local oscillator frequency of 2.5 THz the receiver has offered a DSB noise temperature of 950 K. When compared to the previous result of 1300 K obtained at the same local oscillator frequency for devices fabricated with an ex situ route, such a low value of the noise temperature may also be attributed to the improved gold contacts. |
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Place of Publication |
Groningen, Netherlands |
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no |
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412 |
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