Underground mining is a hazardous industrial activity. In order to provide a safe working environment for miners, a Wireless Sensor Network (WSN) technology has been used for security monitoring. It can provide a wide...Underground mining is a hazardous industrial activity. In order to provide a safe working environment for miners, a Wireless Sensor Network (WSN) technology has been used for security monitoring. It can provide a wide range of surveillance with a relatively low cost. In this study, an Energy-Based Multipath Routing (EBMR) protocol is proposed, which considers residual energy capacity and link quality in choosing hops and routing paths. Hops and paths with a high residual energy capacity and link quality will have the best chance to be selected to transmit data packages. Since the EBMR stores several routes in the routing table, when the current path fails, another path will be chosen to fulfill the task immediately. In this way, EBMR improves reliability and decrease time latency. Compared to AOMDV and REAR, EBMR decreases time latency by 51% and 12%.展开更多
Influenced by the environment and nodes status,the quality of link is not always stable in actual wireless sensor networks( WSNs). Poor links result in retransmissions and more energy consumption. So link quality is a...Influenced by the environment and nodes status,the quality of link is not always stable in actual wireless sensor networks( WSNs). Poor links result in retransmissions and more energy consumption. So link quality is an important issue in the design of routing protocol which is not considered in most traditional clustered routing protocols. A based on energy and link quality's routing protocol( EQRP) is proposed to optimize the clustering mechanism which takes into account energy balance and link quality factors. EQRP takes the advantage of high quality links to increase success rate of single communication and reduce the cost of communication. Simulation shows that,compared with traditional clustered protocol,EQRP can perform 40% better,in terms of life cycle of the whole network.展开更多
As a core technology of Intemet of Things （loT）, Wireless Sensor Network （WSN） has become a research hotspot recently. More and more WSNs are being deployed in highly mobile environments. The fast moving sensor no...As a core technology of Intemet of Things （loT）, Wireless Sensor Network （WSN） has become a research hotspot recently. More and more WSNs are being deployed in highly mobile environments. The fast moving sensor nodes bring significant challenges for the routing decision. In this paper, we propose an efficient logical location method, and designe a mobility estimating metric and derive a novel Green Mobility Estirmtion- based Routing protocol （G-MER） for WSNs. We also set up a full framework to evaluate its per- formance. Simulation results illustrate that G-MER achieves a fairly better perforrmnce in terrm of broadcast times and link failures than AODV. What＇s more, it decreases the mean hops by about 0.25 and reduces energy consumption by about 10% during the whole experiment. All the results show that G-MER can be effectively used in fast- moving and limited resource scenarios.展开更多
Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graph...Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors （GFETs）. Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a （deprotonating） hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system.展开更多
Organic field-effect transistors（OFETs） offer great potential applications in chemical and biological sensing for homeland security,environmental monitoring,industry manufacturing,and medical/biological detection. M...Organic field-effect transistors（OFETs） offer great potential applications in chemical and biological sensing for homeland security,environmental monitoring,industry manufacturing,and medical/biological detection. Many studies concentrate on sensitivity and selectivity improvement of OFET-based sensors. We report four organic semiconductors with different alkyl side chain lengths but the same π-conjugated core structure for OFETs. Our work focuses on the molecular structure of organic semiconductors（OSCs）. Alkyl side chains can hinder the diffusion of ammonia into the OSCs layer,which blocks the interaction between ammonia and conducting channel. The result also reveals the relationship between the alky chain and the film thickness in sensitivity control. These results are expected to be a guide to the molecular design of organic semiconductors and the choice of OSCs.展开更多
In this paper, we produce porous silicon （PSi） by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain ...In this paper, we produce porous silicon （PSi） by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody （VHH）. The binding of hen egg white lysozyme （HEWL） and VHH causes a red shift in the reflection spectrum of the biosensor. The red shift is proportional to the VHH concenlration in the range from 14 gg.ml-I to 30 pg.ml~ with a detection limit of 0.648 ng.ml~. The research is useful for the development of label-free biosensor applied in the rapid and sensitive determination of small molecules.展开更多
基金Financial support for this study, provided by the National Natural Science Foundation of China (No.60674002) the Science and Technology Research of the Ministry of Railways of China (No. 2006x006-E), is gratefully acknowledged
文摘Underground mining is a hazardous industrial activity. In order to provide a safe working environment for miners, a Wireless Sensor Network (WSN) technology has been used for security monitoring. It can provide a wide range of surveillance with a relatively low cost. In this study, an Energy-Based Multipath Routing (EBMR) protocol is proposed, which considers residual energy capacity and link quality in choosing hops and routing paths. Hops and paths with a high residual energy capacity and link quality will have the best chance to be selected to transmit data packages. Since the EBMR stores several routes in the routing table, when the current path fails, another path will be chosen to fulfill the task immediately. In this way, EBMR improves reliability and decrease time latency. Compared to AOMDV and REAR, EBMR decreases time latency by 51% and 12%.
基金Supported by the National Natural Science Foundation of China(No.61300180)Beijing Higher Education Young Elite Teacher Project(No.YETP1755)+1 种基金the Fundamental Research Funds for the Central Universities of China(No.TD2014-01)the Importation and Development of High-caliber Talents Project of Beijing Municipal Institutions(No.CIT&TCD201504039)
文摘Influenced by the environment and nodes status,the quality of link is not always stable in actual wireless sensor networks( WSNs). Poor links result in retransmissions and more energy consumption. So link quality is an important issue in the design of routing protocol which is not considered in most traditional clustered routing protocols. A based on energy and link quality's routing protocol( EQRP) is proposed to optimize the clustering mechanism which takes into account energy balance and link quality factors. EQRP takes the advantage of high quality links to increase success rate of single communication and reduce the cost of communication. Simulation shows that,compared with traditional clustered protocol,EQRP can perform 40% better,in terms of life cycle of the whole network.
基金This paper was partially supported by the National Natural Science Foundation of China under Crants No. 61003283, No. 61001122 Beijing Natural Science Foundation of China under Crants No. 4102064+2 种基金 the Natural Science Foundation of Jiangsu Province under Crant No. BK2011171 the National High-Tech Research and Development Program of China under Crant No. 2011 AA010701 the Fundamental Research Funds for the Cen- tral Universities under Ccants No. 2011RC0507, No. 2012RO3603.
文摘As a core technology of Intemet of Things （loT）, Wireless Sensor Network （WSN） has become a research hotspot recently. More and more WSNs are being deployed in highly mobile environments. The fast moving sensor nodes bring significant challenges for the routing decision. In this paper, we propose an efficient logical location method, and designe a mobility estimating metric and derive a novel Green Mobility Estirmtion- based Routing protocol （G-MER） for WSNs. We also set up a full framework to evaluate its per- formance. Simulation results illustrate that G-MER achieves a fairly better perforrmnce in terrm of broadcast times and link failures than AODV. What＇s more, it decreases the mean hops by about 0.25 and reduces energy consumption by about 10% during the whole experiment. All the results show that G-MER can be effectively used in fast- moving and limited resource scenarios.
基金This research was supported by the Nano/Bio Interface Center through the National Science Foundation Nanoscale Science and Engineering Center （NSEC） DMR08-32802, and the work involved use of its facilities. Support from Lockheed Martin is also gratefully acknowledged. M.L. acknowledges the support of the Science, Mathematics, And Research for Transformation （SMART） Fellowship.
文摘Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors （GFETs）. Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a （deprotonating） hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system.
基金financially supported by the National Natural Science Foundation of China(21302142 and 51603151)the National Key Research and Development Program of China(2017YFA0103900 and 2017YFA0103904)+1 种基金the 1000 Youth Talent Planthe Fundamental Research Funds for the Central Universities of China
文摘Organic field-effect transistors（OFETs） offer great potential applications in chemical and biological sensing for homeland security,environmental monitoring,industry manufacturing,and medical/biological detection. Many studies concentrate on sensitivity and selectivity improvement of OFET-based sensors. We report four organic semiconductors with different alkyl side chain lengths but the same π-conjugated core structure for OFETs. Our work focuses on the molecular structure of organic semiconductors（OSCs）. Alkyl side chains can hinder the diffusion of ammonia into the OSCs layer,which blocks the interaction between ammonia and conducting channel. The result also reveals the relationship between the alky chain and the film thickness in sensitivity control. These results are expected to be a guide to the molecular design of organic semiconductors and the choice of OSCs.
基金supported by the National Natural Science Foundation of China (No.60968002)
文摘In this paper, we produce porous silicon （PSi） by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody （VHH）. The binding of hen egg white lysozyme （HEWL） and VHH causes a red shift in the reflection spectrum of the biosensor. The red shift is proportional to the VHH concenlration in the range from 14 gg.ml-I to 30 pg.ml~ with a detection limit of 0.648 ng.ml~. The research is useful for the development of label-free biosensor applied in the rapid and sensitive determination of small molecules.
