Sensor node-assisted asynchronous cooperative spectrum sensing for cognitive radio network

In order to take advantage of the asynchronous sensing information, alleviate the sensing overhead of secondary users （SUs） and improve the detection performance, a sensor node-assisted asynchronous cooperative spectrum sensing （SN-ACSS） scheme for cognitive radio （CR） network （CRN） was proposed. In SN-ACSS, each SU is surrounded by sensor nodes （SNs）, which asynchronously make hard decisions and soft decisions based on the Bayesian fusion rule instead of the SU. The SU combines these soft decisions and makes the local soft decision. Finally, the fusion center （FC） fuses the local soft decisions transmitted from SUs with different weight coefficients to attain the final soft decision. Besides, the impact of the statistics of licensed band occupancy on detection performance and the fact that different SNs have different sensing contributions are also considered in SN-ACSS scheme. Numerical results show that compared with the conventional synchronous cooperative spectrum sensing （SCSS） and the existing ACSS schemes, SN-ACSS algorithm achieves a better detection performance and lower cost with the same number of SNs.

Interactions between pyridinium and Nd^(3+)

In this paper,2D asynchronous spectra generated by using the DAOSD approach was utilized to probe interactions between Nd^3＋ and pyridinium dissolved in aqueous solution.A series of cross peaks in the resultant 2D asynchronous spectrum confirms the occurrence of intermolecular interaction between Nd^3＋and pyridinium.However,no coordination occurs between Nd^3＋ and pyridinium.Interaction between πelectron from aromatic system and/electron from lanthanide ions account for the appearance of cross peaks in 2D asynchronous spectra.Because of the interaction,the emission spectrum of pyridinium exhibits a significant change when neodymium perchlorate was introduced into the system.