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- Engelmark, O., et al.
(författare)
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Ecological effects and management aspects of an exotic tree species : the case of lodgepole pine in Sweden
- 2001
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Ingår i: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 141:02-jan, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- The North American tree Pinus contorta var, latifolia was experimentally introduced in Sweden already in the 1920s, and has been used in Swedish forestry on a large scale since the 1970s. These plantations now cover 565,000 ha, mainly in the northern area. In this paper we summarize and discuss existing ecological knowledge of this species introduction. With regard to longterm sustainability we suggest management means to minimize harmful effects of the introduction on ecosystems. These include aspects of self dispersal, pests, ecosystem and landscape structures, and also ecological processes and biodiversity. We also focus on observed and possible interactions in the ecosystems. As Pinus contorta seeds are disseminated and trees regenerated outside initial plantations, this may have future bearings on biodiversity. We suggest a strategy which takes account of the uncertainty in predicting future ecological effects. The strategy includes areal restrictions and zones without Pinus contorta, but also to set up a monitoring program. Observations of adverse effects from the plantations would then give the possibility to adjust P. contorta management.
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- Ohlsson, Lars, et al.
(författare)
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First InGaAs lateral nanowire MOSFET RF noise measurements and model
- 2017
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Ingår i: 75th Annual Device Research Conference, DRC 2017. - 9781509063277
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Konferensbidrag (refereegranskat)abstract
- The first radio frequency (RF) noise measurements on lateral nanowire metal-oxide-semiconductor field-effect transistors (MOSFETs) and a noise model are presented. We have characterized the RF noise and scattering parameters of an indium gallium arsenide (InGaAs) device. A fitted model yields extrapolated ft = 316 GHz current gain cutoff and fmax = 166 GHz maximum oscillation frequency. This device technology is being developed for millimeter wave circuit implementations, targeting a 94 GHz carrier frequency. The modeled intrinsic Fmin < 1dB minimum noise figure obtained promises performance at the target band, given reduction of gate parasitics. In any wireless system, noise and bandwidth limits the performance. Understanding of RF noise in nanowire MOSFET devices is thereby key for realization of future radar and communications systems.
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- Zota, Cezar B., et al.
(författare)
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InGaAs tri-gate MOSFETs with record on-current
- 2017
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Ingår i: 2016 IEEE International Electron Devices Meeting, IEDM 2016. - 9781509039012 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- We demonstrate InGaAs tri-gate MOSFETs with an on-current of ION = 650 μA/μm at VDD = 0.5 V and IOFF = 100 nA/μm, enabled by an inverse subthreshold slope of SS = 66 mV/decade and transconductance of gm = 3 mS/μm, a Q-factor of 45. This is the highest reported Ion for both Si-based and III-V MOSFETs. These results continue to push III-V MOSFET experimental performance towards its theoretical limit. We find an improvement in SS from 81 to 75 mV/dec. as the effective oxide thickness (EOT) is scaled down from 1.4 to 1 nm, as well as improvements in SS, gd and DIBL from reducing the nanowire width. We also find that electron mobility remains constant as the width is scaled to 18 nm.
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