The high-frequency(HF) communication is one of essential communication methods for military and emergency application. However, the selection of communication frequency channel is always a difficult problem as the cro...The high-frequency(HF) communication is one of essential communication methods for military and emergency application. However, the selection of communication frequency channel is always a difficult problem as the crowded spectrum, the time-varying channels, and the malicious intelligent jamming. The existing frequency hopping, automatic link establishment and some new anti-jamming technologies can not completely solve the above problems. In this article, we adopt deep reinforcement learning to solve this intractable challenge. First, the combination of the spectrum state and the channel gain state is defined as the complex environmental state, and the Markov characteristic of defined state is analyzed and proved. Then, considering that the spectrum state and channel gain state are heterogeneous information, a new deep Q network(DQN) framework is designed, which contains multiple sub-networks to process different kinds of information. Finally, aiming to improve the learning speed and efficiency, the optimization targets of corresponding sub-networks are reasonably designed, and a heterogeneous information fusion deep reinforcement learning(HIF-DRL) algorithm is designed for the specific frequency selection. Simulation results show that the proposed algorithm performs well in channel prediction, jamming avoidance and frequency channel selection.展开更多
Methyl vinyl ketone oxide,an unsaturated four-carbon Criegee intermediate produced from the ozonolysis of isoprene has been recognized to play a key role in determining the tropospheric OH concentration.It exists in f...Methyl vinyl ketone oxide,an unsaturated four-carbon Criegee intermediate produced from the ozonolysis of isoprene has been recognized to play a key role in determining the tropospheric OH concentration.It exists in four configurations(anti-anti,anti-syn,synanti,and syn-syn)due to two different substituents of saturated methyl and unsaturated vinyl groups.In this study,we have carried out the electronic structure calculation at the multi-configurational CASSCF and multi-state MS-CASPT2 levels,as well as the trajectory surface-hopping nonadiabatic dynamics simulation at the CASSCF level to reveal the different fates of syn/anti configurations in photochemical process.Our results show that the dominant channel for the S1-state decay is a ring closure,isomerization to dioxirane,during which,the syn(C-O)configuration with an intramolecular hydrogen bond shows slower nonadiabatic photoisomerization.More importantly,it has been found for the first time in photochemistry of Criegee intermediate that the cooperation of two heavy groups(methyl and vinyl)leads to an evident pyramidalization of C3 atom in methyl-vinyl Criegee intermediate,which then results in two structurally-independent minimal-energy crossing points(CIs)towards the syn(C-O)and anti(C-O)sides,respectively.The preference of surface hopping for a certain CI is responsible for the different dynamics of each configuration.展开更多
This paper designed and synthesized a series of different chain length of phthalonitrile-terminated oligo （phthalazinone imide）, it has good water solubility, and can be under normal atmospheric pressure to form the...This paper designed and synthesized a series of different chain length of phthalonitrile-terminated oligo （phthalazinone imide）, it has good water solubility, and can be under normal atmospheric pressure to form the s-triazine rings-containing thermosetting oligo （phthalazine imide）. Compared with the traditional thermosetting resin, the resin has the advantages of high temperature resistance, high strength, flame retardant, resistance to chemical corrosion.展开更多
基金supported by Guangxi key Laboratory Fund of Embedded Technology and Intelligent System under Grant No. 2018B-1the Natural Science Foundation for Distinguished Young Scholars of Jiangsu Province under Grant No. BK20160034+1 种基金the National Natural Science Foundation of China under Grant No. 61771488, No. 61671473 and No. 61631020in part by the Open Research Foundation of Science and Technology on Communication Networks Laboratory
文摘The high-frequency(HF) communication is one of essential communication methods for military and emergency application. However, the selection of communication frequency channel is always a difficult problem as the crowded spectrum, the time-varying channels, and the malicious intelligent jamming. The existing frequency hopping, automatic link establishment and some new anti-jamming technologies can not completely solve the above problems. In this article, we adopt deep reinforcement learning to solve this intractable challenge. First, the combination of the spectrum state and the channel gain state is defined as the complex environmental state, and the Markov characteristic of defined state is analyzed and proved. Then, considering that the spectrum state and channel gain state are heterogeneous information, a new deep Q network(DQN) framework is designed, which contains multiple sub-networks to process different kinds of information. Finally, aiming to improve the learning speed and efficiency, the optimization targets of corresponding sub-networks are reasonably designed, and a heterogeneous information fusion deep reinforcement learning(HIF-DRL) algorithm is designed for the specific frequency selection. Simulation results show that the proposed algorithm performs well in channel prediction, jamming avoidance and frequency channel selection.
基金supported by the the National Natural Science Foundation of China(No.21873060and No.21473107)the Fundamental Research Funds for the Central Universities(No.GK201901007,No.2018CBLY004)。
文摘Methyl vinyl ketone oxide,an unsaturated four-carbon Criegee intermediate produced from the ozonolysis of isoprene has been recognized to play a key role in determining the tropospheric OH concentration.It exists in four configurations(anti-anti,anti-syn,synanti,and syn-syn)due to two different substituents of saturated methyl and unsaturated vinyl groups.In this study,we have carried out the electronic structure calculation at the multi-configurational CASSCF and multi-state MS-CASPT2 levels,as well as the trajectory surface-hopping nonadiabatic dynamics simulation at the CASSCF level to reveal the different fates of syn/anti configurations in photochemical process.Our results show that the dominant channel for the S1-state decay is a ring closure,isomerization to dioxirane,during which,the syn(C-O)configuration with an intramolecular hydrogen bond shows slower nonadiabatic photoisomerization.More importantly,it has been found for the first time in photochemistry of Criegee intermediate that the cooperation of two heavy groups(methyl and vinyl)leads to an evident pyramidalization of C3 atom in methyl-vinyl Criegee intermediate,which then results in two structurally-independent minimal-energy crossing points(CIs)towards the syn(C-O)and anti(C-O)sides,respectively.The preference of surface hopping for a certain CI is responsible for the different dynamics of each configuration.
文摘This paper designed and synthesized a series of different chain length of phthalonitrile-terminated oligo （phthalazinone imide）, it has good water solubility, and can be under normal atmospheric pressure to form the s-triazine rings-containing thermosetting oligo （phthalazine imide）. Compared with the traditional thermosetting resin, the resin has the advantages of high temperature resistance, high strength, flame retardant, resistance to chemical corrosion.
