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Jiang F.,Tianjin University | Zheng J.,Tianjin University | Liang L.,China Aviation Industry Corporation | Zhang M.,Tianjin University | Wang Y.,Tianjin University
Journal of Materials Science: Materials in Electronics

We synthetize La0.1Ca0.9MnO3 particles with porous microsphere shape through co-precipitation method. The crystal structure and morphology were characterized by XRD and SEM respectively. The particles are orthorhombic calcium lanthanum manganese oxide with porous microsphere shape which is less talked. The test of microwave absorption was carried out by using the network analyzer Agilent HP-8722ES. The microwave absorbing peak is 31 dB at 11.5 GHz and the effective absorbing bandwidth above 10 dB reaches 1.9 GHz in the 11.1–13 GHz. The microwave absorption can be attributed to both the dielectric loss and the magnetic loss, but the former is greater than the latter. © 2015, Springer Science+Business Media New York. Source

Zhuo K.,PLA Air Force Aviation University | Zhang H.-Y.,PLA Air Force Aviation University | Xu D.-H.,Unit 93995 of PLA | Zheng B.,PLA Air Force Aviation University | And 2 more authors.
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics

A channel access strategy based on partial observable Markov decision processes (POMDP) is presented in allusion to the problem of performance degrades seriously when load becomes heavy, the access threshold value settings is lacked in the theoretical basis and unable to effectively support the quality of serive requirement of multi-priority service of the random competition medium access control protocol in airborne network. The dynamic programming function is established by which based on channel occupation cost of different priority burst as the objective function, the compact state-space method is adopted to simplify the solution-finding, the expression for the theory approximately optimal access threshold value within the different priority burst is worked out. The value can provide theoretical foundation for access decision processes of different priority burst and can effectively control the access collision within different priority burst. The simulation results show that transmission performance of delay and success probability can be improved obviously, the real-time and reliability demands of data transmission in military aeronautical communications are satisfied. © 2016, Chinese Institute of Electronics. All right reserved. Source

Zheng J.,Tianjin University | Song X.,Tianjin University | Liu X.,China Aviation Industry Corporation | Chen W.,Tianjin University | And 2 more authors.
Materials Letters

We present a facile method to synthetize CoFe 2O 4/ZnO nanoparticles with hexagonal shape through high temperature hydrolysis of chelated zinc diethylene glycol alkoxide complexes in alkaline Diethylene Glycol solution in the presence of CoFe 2O 4 nanoparticles. X-ray diffraction data show that the obtained nanoparticles are composed of CoFe 2O 4 and ZnO. The hexagonal particle morphology of the resulting nanoparticles was analyzed using transmission electron microscopy, indicating that the shape of the nanoparticles is hexagonal with a mean diameter below 100 nm. Electromagnetic parameters in GHz frequency range was measured by a network analyzer, which reveals that magnetic and dielectric properties are combined due to both the interfacial polarization process and multiresonance in the as-prepared hexagonal CoFe 2O 4/ZnO nanoparticles. © 2011 Elsevier B.V. All rights reserved. Source

Sun S.-L.,Northwestern Polytechnical University | Chen R.,China Aviation Industry Corporation | Sun L.,Northwestern Polytechnical University | Yan J.,Northwestern Polytechnical University
Xitong Fangzhen Xuebao / Journal of System Simulation

Firstly, three different infrared simulate thinking was analyzed, and through the comparing, a promote method based on Vega Prime (VP) engine was purposed. Then, according to the synthesizing of experience data and thermodynamic balance model, the tank radiation field with both internal thermal source and no internal thermal source was given. Meanwhile, the simulation methods of key modules were accomplished. At the end, the result of experimentation of three different thinking shows that each of their infrared tank target images carved representative signification. The characteristic of three thinking were achieved through the comparing with the real infrared images. These outcomes show an authentic depiction of the experimentation, which has taken on an application value as well. Source

Xu X.,China Aviation Industry Corporation | Zhou J.-H.,China Aviation Industry Corporation | Zhang Y.-D.,China Aviation Industry Corporation | Sun Y.,Engine Co.
Reneng Dongli Gongcheng/Journal of Engineering for Thermal Energy and Power

With a split-shaft gas turbine generator unit serving as the prototype, the dynamic characteristics of the gas turbine were analyzed by using the multi-loop feedback PI control and compressor inter-stage air bleeding technology under the condition of the unit being forced to shed its load. In the meantime, according to the volume and inertia method, a nonlinear mathematic model for gas turbines was established and then in accordance with the model thus established, a model for simulating the dynamic performance of a gas turbine was built by making use of a Matlab/simulink platform. The test and simulation results show that the above-mentioned split-shaft gas turbine has an ability to suddenly reject 80% of its rated load. Among them, when the load of the gas turbine is 20%, its control quality is relatively ideal. The simulation model can correctly reflect the dynamic characteristics of the gas turbine under the condition of the gas turbine subjected to a big disturbance, thus meeting the precision and real-time requirements for dynamic simulation. © 2016, Harbin Research Institute. All right reserved. Source

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