3,044 research outputs found
Mulches and pheromones - plant protection tools for organic black currant production
Different mulches have been studied in organic currant production since 1997 at MTT Ecological Production in S:t Michel. Mulches, especially black plastic, suppressed weeds effectively. Since green mass mulch decomposes fast on the soil surface, it can be recommended mainly as an additional fertilizer.
Lepidopterous pests Synanthedon tipuliformis, Euhyponomeutoides albithoracellus and Lampronia capitella are difficult to control even by chemicals. Therefore pheromone-based management was studied in 1999-2003
Image charge dynamics in time-dependent quantum transport
In this work we investigate the effects of the electron-electron interaction
between a molecular junction and the metallic leads in time-dependent quantum
transport. We employ the recently developed embedded Kadanoff-Baym method
[Phys. Rev. B 80, 115107 (2009)] and show that the molecule-lead interaction
changes substantially the transient and steady-state transport properties. We
first show that the mean-field Hartree-Fock (HF) approximation does not capture
the polarization effects responsible for the renormalization of the molecular
levels neither in nor out of equilibrium. Furthermore, due to the time-local
nature of the HF self-energy there exists a region in parameter space for which
the system does not relax after the switch-on of a bias voltage. These and
other artifacts of the HF approximation disappear when including correlations
at the second-Born or GW levels. Both these approximations contain polarization
diagrams which correctly account for the screening of the charged molecule. We
find that by changing the molecule-lead interaction the ratio between the
screening and relaxation time changes, an effect which must be properly taken
into account in any realistic time-dependent simulation. Another important
finding is that while in equilibrium the molecule-lead interaction is
responsible for a reduction of the HOMO-LUMO gap and for a substantial
redistribution of the spectral weight between the main spectral peaks and the
induced satellite spectrum, in the biased system it can have the opposite
effect, i.e., it sharpens the spectral peaks and opens the HOMO-LUMO gap.Comment: 18 pages, 26 figure
Very Wideband automated On-Wafer noise figure and Gain measurements At 50-110
On-wafer noise figure and insertion gain measurement set-ups have been developed over 50-110 GHz frequency range. Wafer scale noise figure and insertion gain measurements can be done in an automatic manner using PC controlled automated probe station and in-house written software. In narrow band measurements, large systematic errors may remain undiscovered. These errors are usually caused by reflections in the set-up, which are difficult to calibrate out. Wideband measurements are often the only method, which can efficiently reveal these errors. This aspect is increasingly important as frequency increases
Novel Data Acquisition System for Silicon Tracking Detectors
We have developed a novel data acquisition system for measuring tracking
parameters of a silicon detector in a particle beam. The system is based on a
commercial Analog-to-Digital VME module and a PC Linux based Data Acquisition
System. This DAQ is realized with C++ code using object-oriented techniques.
Track parameters for the beam particles were reconstructed using off-line
analysis code and automatic detector position alignment algorithm.
The new DAQ was used to test novel Czochralski type silicon detectors. The
important silicon detector parameters, including signal size distributions and
signal to noise distributions, were successfully extracted from the detector
under study. The efficiency of the detector was measured to be 95 %, the
resolution about 10 micrometers, and the signal to noise ratio about 10.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 5 eps figures. PSN
TUGP00
Digital Technologies for Transport and Mobility: Challenges, Trends and Perspectives
This white paper aims at presenting the ideas emerging from the different fields pertaining to transport and mobility, to describe the capacities of current state-of-the-art digital technologies and the perspectives that are expected to shape the future of transport and mobility
Interpreting eddy covariance data from heterogeneous Siberian tundra : land-cover-specific methane fluxes and spatial representativeness
The non-uniform spatial integration, an inherent feature of the eddy covariance (EC) method, creates a challenge for flux data interpretation in a heterogeneous environment, where the contribution of different land cover types varies with flow conditions, potentially resulting in biased estimates in comparison to the areally averaged fluxes and land cover attributes. We modelled flux footprints and characterized the spatial scale of our EC measurements in Tiksi, a tundra site in northern Siberia. We used leaf area index (LAI) and land cover class (LCC) data, derived from very-high-spatial-resolution satellite imagery and field surveys, and quantified the sensor location bias. We found that methane (CH4) fluxes varied strongly with wind direction (-0.09 to 0.59 mu gCH(4)m(-2) s(-1) on average) during summer 2014, reflecting the distribution of different LCCs. Other environmental factors had only a minor effect on short-term flux variations but influenced the seasonal trend. Using footprint weights of grouped LCCs as explanatory variables for the measured CH4 flux, we developed a multiple regression model to estimate LCC group-specific fluxes. This model showed that wet fen and graminoid tundra patches in locations with topography-enhanced wetness acted as strong sources (1.0 mu gCH(4) m(-2) s(-1) during the peak emission period), while mineral soils were significant sinks (-0.13 mu gCH(4) m(-2) s(-1)). To assess the representativeness of measurements, we upscaled the LCC group-specific fluxes to different spatial scales. Despite the landscape heterogeneity and rather poor representativeness of EC data with respect to the areally averaged LAI and coverage of some LCCs, the mean flux was close to the CH4 balance upscaled to an area of 6.3 km(2), with a location bias of 14 %. We recommend that EC site descriptions in a heterogeneous environment should be complemented with footprint-weighted high-resolution data on vegetation and other site characteristics.Peer reviewe
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