This paper proposes a simple and efficient distributed algorithm for calculating minimal dominating set in wireless sensor network. This method can avoid maintaining the connectivities between backbone hosts. Consider...This paper proposes a simple and efficient distributed algorithm for calculating minimal dominating set in wireless sensor network. This method can avoid maintaining the connectivities between backbone hosts. Considering that the hosts in mobile networks have different characteristics, this paper proposes a method of calculating minimal dominating set with weight. The nodes can be chosen to form a minimal dominating set when the network topology changes. For the host switch on/off operation, the updating algorithm was provided. The change in the status of a hostaffects only the status of hosts in the restricted vicinity. Simulation results show that the proposed method can ensure fewer dominators but with higher weight to form the minimal dominating set and the nodes can be adaptive to the changes of network topology.展开更多
In this work,molybdenum disulfide quantum dots（MoS2 QDs） were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid detection.When joining MnO2 nan...In this work,molybdenum disulfide quantum dots（MoS2 QDs） were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid detection.When joining MnO2 nanosheets into MoS2 QDs solution,they produced an obvious fluorescence quenching,which should be due to inner filter effect（IFE）.Meanwhile,the fluorescent probe was formed,Interestingly,we found that this quenching phenomenon disappeared with the addition of ascorbic acid,In other words,the fluorescence gradually restored.This recovery phenomenon is mainly due to the reduction effect of ascorbic acid for MnO2 nanosheets.Under the optimum conditions,the limit of detection（LOD） of 39 nmol/L for ascorbic acid was achieved with a linear range of 0.33-5.00 μmol/L.The repeatability was better than 5.0% for ascorbic acid in both standard and fruit samples（n = 3）.Moreover,the as-fabricated fluorescent sensing system was successfully employed to detect the ascorbic acid levels in hawthorn and jujube with satisfactory results.展开更多
This paper presents an approach for analyzing the key parts of a general digital radio frequency(RF) charge sampling mixer based on discrete-time charge values.The cascade sampling and filtering stages are analyzed an...This paper presents an approach for analyzing the key parts of a general digital radio frequency(RF) charge sampling mixer based on discrete-time charge values.The cascade sampling and filtering stages are analyzed and expressed in theoretical formulae.The effects of a pseudo-differential structure and CMOS switch-on resistances on the transfer function are addressed in detail.The DC-gain is restrained by using the pseudo-differential structure.The transfer gain is reduced because of the charge-sharing time constant when taking CMOS switch-on resistances into account.The unfolded transfer gains of a typical digital RF charge sampling mixer are analyzed in different cases using this approach.A circuit-level model of the typical mixer is then constructed and simulated in Cadence SpectreRF to verify the results.This work informs the design of charge-sampling,infinite impulse response(ⅡR) filtering,and finite impulse response(FIR) filtering circuits.The discrete-time approach can also be applied to other multi-rate receiver systems based on charge sampling techniques.展开更多
基金Supported by National Natural Science Foundation of China (No.60973141)Natural Science Foundation of Tianjin (No.09JCYBJC00300)
文摘This paper proposes a simple and efficient distributed algorithm for calculating minimal dominating set in wireless sensor network. This method can avoid maintaining the connectivities between backbone hosts. Considering that the hosts in mobile networks have different characteristics, this paper proposes a method of calculating minimal dominating set with weight. The nodes can be chosen to form a minimal dominating set when the network topology changes. For the host switch on/off operation, the updating algorithm was provided. The change in the status of a hostaffects only the status of hosts in the restricted vicinity. Simulation results show that the proposed method can ensure fewer dominators but with higher weight to form the minimal dominating set and the nodes can be adaptive to the changes of network topology.
基金financially supported by National Nature Science Foundation of China (No. 21475053)
文摘In this work,molybdenum disulfide quantum dots（MoS2 QDs） were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid detection.When joining MnO2 nanosheets into MoS2 QDs solution,they produced an obvious fluorescence quenching,which should be due to inner filter effect（IFE）.Meanwhile,the fluorescent probe was formed,Interestingly,we found that this quenching phenomenon disappeared with the addition of ascorbic acid,In other words,the fluorescence gradually restored.This recovery phenomenon is mainly due to the reduction effect of ascorbic acid for MnO2 nanosheets.Under the optimum conditions,the limit of detection（LOD） of 39 nmol/L for ascorbic acid was achieved with a linear range of 0.33-5.00 μmol/L.The repeatability was better than 5.0% for ascorbic acid in both standard and fruit samples（n = 3）.Moreover,the as-fabricated fluorescent sensing system was successfully employed to detect the ascorbic acid levels in hawthorn and jujube with satisfactory results.
基金supported by the National Natural Science Foundation of China (No.90407011)the National High-Tech Research and Development Program (863) of China (No.2007AA01Z2b3)China Postdoctoral Science Foundation (No.20090451439)
文摘This paper presents an approach for analyzing the key parts of a general digital radio frequency(RF) charge sampling mixer based on discrete-time charge values.The cascade sampling and filtering stages are analyzed and expressed in theoretical formulae.The effects of a pseudo-differential structure and CMOS switch-on resistances on the transfer function are addressed in detail.The DC-gain is restrained by using the pseudo-differential structure.The transfer gain is reduced because of the charge-sharing time constant when taking CMOS switch-on resistances into account.The unfolded transfer gains of a typical digital RF charge sampling mixer are analyzed in different cases using this approach.A circuit-level model of the typical mixer is then constructed and simulated in Cadence SpectreRF to verify the results.This work informs the design of charge-sampling,infinite impulse response(ⅡR) filtering,and finite impulse response(FIR) filtering circuits.The discrete-time approach can also be applied to other multi-rate receiver systems based on charge sampling techniques.
