| 1. |
- Basagni, Andrea, et al.
(författare)
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On-surface photo-dissociation of C-Br bonds: towards room temperature Ullmann coupling
- 2015
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; 51:63, s. 12593-12596
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Tidskriftsartikel (refereegranskat)abstract
- The surface-assisted synthesis of gold-organometallic hybrids on the Au(111) surface both by thermo-and light-initiated dehalogenation of bromo-substituted tetracene is reported. Combined X-ray photoemission (XPS) and scanning tunneling microscopy (STM) data reveal a significant increase of the surface order when mild reaction conditions are combined with 405 nm light irradiation.
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| 2. |
- Kaushik, K., et al.
(författare)
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Experimental demonstration of multi-hop RF energy transfer
- 2013
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Ingår i: 2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467362351 ; , s. 538-542
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Konferensbidrag (refereegranskat)abstract
- Batteries of field nodes in a wireless sensor network pose an upper limit on the network lifetime. Energy harvesting and harvesting aware medium access control protocols have the potential to provide uninterrupted network operation, as they aim to replenish the lost energy so that energy neutral operation of the energy harvesting nodes can be achieved. To further improve the energy harvesting process, there is a need for novel schemes so that maximum energy is harvested in a minimum possible time. Multi-hop radio frequency (RF) energy transfer is one such solution that addresses these needs. With the optimal placement of energy relay nodes, multi-hop RF energy transfer can save energy of the source as well as time for the harvesting process. In this work we experimentally demonstrate multi-hop RF energy transfer, wherein two-hop energy transfer is shown to achieve significant energy and time savings with respect to the single-hop case. It is also shown that the gain obtained can be translated to energy transfer range extension.
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| 3. |
- Kaushik, K., et al.
(författare)
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RF energy harvester-based wake-up receiver
- 2015
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Ingår i: Sensors Journal IEEE. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479982035 - 9781479982028 ; , s. 6270-6278
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Konferensbidrag (refereegranskat)abstract
- Wake-up receivers (WuRxs) can improve the lifetime of a wireless sensor network by reducing energy consumption from undesirable idle listening. The amplitude level of the incoming RF signal is used by a WuRx to generate an interrupt and wake up the radio of a sleeping sensor node. Existing passive WuRx designs are generally based on RFID tags that incur high cost and complexity. Thus, there is a need for cost-effective and low-complexity WuRxs suited for both long-range and directed wake-ups. In this work, we present a WuRx design using an RF energy harvesting circuit (RFHC). Experimental results show that our RFHC-based WuRx can provide a wake-up range sensitivity around 4 cm/mW at low transmit RF powers (<; 20 mff), which scales to a long wake-up range at high powers. Our design also obtains accurate selective wake-ups. We finally present simulation-based studies for optimizing the design of RFHCs that enhance decoding efficiency with improved rise and fall times.
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| 4. |
- Mishra, Deepak, 1990-, et al.
(författare)
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Implementation of multi-path energy routing
- 2014
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Ingår i: 2014 IEEE 25th Annual International Symposium on Personal, Indoor, and Mobile Radio Communication (PIMRC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479949120 ; , s. 1834-1839
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Konferensbidrag (refereegranskat)abstract
- Harvesting energy from radio frequency (RF) waves brings us closer to achieving the goal for perpetual operation of a wireless sensor network (WSN) by replenishing the batteries of the sensor nodes. However, due to restrictions on the maximum transmitted power, path loss, and receiver sensitivity, only a small amount of energy can be harvested. While a dedicated RF source alleviates the problem to some extent, novel techniques are required to boost the energy transfer efficiency of the source. In this paper, we provide the first experimental demonstration of multi-path energy routing (MPER) for the case of a sparsely distributed WSNs and show its improved performance over direct energy transfer (DET). In addition, we extend this concept to the case of densely distributed WSNs and experimentally demonstrate and compare the gains obtained by 2- and 3-path energy routing over DET. Our experimental results show that significant energy gains can be achieved in a dense network deployment even when the node to be charged is partially blocked by the neighboring nodes.
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| 5. |
- Mishra, Deepak, 1990-, et al.
(författare)
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Smart RF energy harvesting communications : Challenges and opportunities
- 2015
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Ingår i: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 0163-6804 .- 1558-1896. ; 53:4, s. 70-78
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Tidskriftsartikel (refereegranskat)abstract
- RF energy harvesting (RFH) is emerging as a potential method for the proactive energy replenishment of next generation wireless networks. Unlike other harvesting techniques that depend on the environment, RFH can be predictable or on demand, and as such it is better suited for supporting quality-of-service-based applications. However, RFH efficiency is scarce due to low RF-to-DC conversion efficiency and receiver sensitivity. In this article, we identify the novel communication techniques that enable and enhance the usefulness of RFH. Backed by some experimental observations on RFH and the current state of the art, we discuss the challenges in the actual feasibility of RFH communications, new research directions, and the obstacles to their practical implementation.
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