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Physical Layer Security in Underlay CCRNs with Fixed Transmit Power
( Songqing Wang ),( Xiaoming Xu ),( Weiwei Yang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.1
In this paper, we investigate physical layer security for multiple decode-and-forward (DF) relaying underlay cognitive radio networks (CRNs) with fixed transmit power at the secondary network against passive eavesdropping attacks. We propose a simple relay selection scheme to improve wireless transmission security based on the instantaneous channel information of all legitimate users and the statistical information about the eavesdropper channels. The closed-form expressions of the probability of non-zero secrecy capacity and the secrecy outage probability (SOP) are derived over independent and non-identically distributed Rayleigh fading environments. Furthermore, we conduct the asymptotic analysis to evaluate the secrecy diversity order performance and prove that full diversity is achieved by using the proposed relay selection. Finally, numerical results are presented to verify the theoretical analysis and depict that primary interference constrain has a significant impact on the secure performance and a proper transmit power for the second transmitters is preferred to be energy-efficient and improve the secure performance.
Yan Wang,Hongbing Wang,Chunling Li,Shuangqing Sun,Songqing Hu 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-
Dissipative particle dynamics (DPD) simulations were applied to investigate the effect of SiO2nanoparticles (SNPs) modified with different tertiary amine chain length and concentration on O/Wemulsion properties, the influence mechanism was also revealed from the molecular level. On this basis,the influence of the modified SNPs volume fraction in the emulsion system was studied. The resultsshowed that with the increase number of tertiary amine chain alkyl carbon, the stability of the originalemulsion system wasfirst enhanced and then weakened while the responsiveness of the protonatedemulsion system wasfirst weakened and then slightly enhanced, the number of tertiary amine chainsmodified on SNPs has the same influence rule on emulsion performance, which was determined by thehydrophobicity of modified SNPs. In addition, with the increase of the modified SNPs volume fraction inthe emulsion system, the stability of the emulsion is gradually enhanced. However, when the volumefraction of SiO2 exceeds 3%, the amplitude of stability enhancement decreases. The increase in theinteraction energy between oil droplets in the equilibrium process is caused by emulsion fusion, which inturn is affected by SNPs. The repulsive force between oil and water is greater than that between two oildrops, which is the reason for the oil drop fusion. The presence of SNPs can reduce the repulsive forcebetween oil and water to different degrees, thus slowing down the fusion of emulsion.
Shuangqing Sun,Yan Wang,Congtai Yuan,Hongbing Wang,Wendong Wang,Jianhui Luo,Chunling Li,Songqing Hu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.82 No.-
Experiment and molecular dynamics simulation were carried out to study the tunable stability of oilcontainingSDS-stabilized Nitrogen-in-water foam. The experimental results show that the foam stabilitycould be tuned by the concentrations of SDS and modified SiO2 nanoparticles. In the foam systems with alow SDS concentration (0.2 wt.%), the foams show poor stability and the foam stability was almost notaffected by the addition of modified SiO2 nanoparticles. The foam stability was greatly improved atmoderate SDS concentration (0.5 wt.%), it enhancedfirst and then weakened with the increase ofmodified SiO2 concentration, and the half-life time achieved a maximum value of 1292 s at 0.05 wt.%modified SiO2. However, at high SDS concentration (0.8 wt.%), the foam stability was pretty good exceptfor when the modified SiO2 concentration is too high (>0.2 wt.%). The microscopic mechanism wasobtained by investigating the structural and dynamic properties of the foamfilm. The simulation workshowed consistent results of foam stability with the experimental results. Moreover, it also revealed thatthe concentration and configuration of SDS will affect its interaction with SiO2 and oil molecule, which iscritical to foam stability.
Active control of amplitude and phase of high-power RF systems in EAST ICRF heating experiments
Zhu Guanghui,Liu Lunan,Mao Yuzhou,Zhang Xinjun,Guo Yaoyao,Ai Lin,Jiang Runhao,Qin Chengming,Zhang Wei,Yang Hua,Yuan Shuai,Wang Lei,Ju Songqing,Wang Yongsheng,Sun Xuan,Yang Zhida,Wang Jinxin,Cheng Yan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2
The EAST ICRF system operating space has been extended in power and phase control with a low-level RF system for the new double-strap antenna. Then the multi-step power and periodic phase scanning experiment were conducted in L-mode plasma, respectively. In the power scanning experiment, the stored energy, radiation power, plasma impedance and the antenna's temperature all have positive responses during the short ramp-ups of PL;ICRF. The core ion temperature increased from 1 keV to 1.5 keV and the core heating area expanded from jZj 5 cmto jZj 10 cm during the injection of ICRF waves. In the phasing scanning experiment, in addition to the same conclusions as the previous relatively phasing scanning experiment, the superposition effect of the fluctuation of stored energy, radiation power and neutron yield caused by phasing change with dual antenna, resulting in the amplitude and phase shift, was also observed. The active control of RF output facilitates the precise control of plasma profiles and greatly benefits future experimental exploration.