PLA Air Force Xian Flight Academy
PLA Air Force Xian Flight Academy
Zhao L.,China Aerospace Science and Technology Corporation |
Zhao L.,Northwestern Polytechnical University |
Li X.-Y.,China Aerospace Science and Technology Corporation |
Hao F.,China Aerospace Science and Technology Corporation |
And 3 more authors.
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2016
In order to eliminate the coupling effects between two actuators driving the nozzle swings, as well as to ensure the precision of control command, the elongation of the two actuators was calculated when the nozzle swung based on the principle of rotation matrix. Further the swing control system for deeply submerged nozzle with front pivot point was designed. The experiment results show when angle of one-way swing reaches 4 degrees, the large ratio(7.15%) between the coupled angle and maximum swing angle exists, the maximum coupled angle is 0.002 degrees only using compensation calculation, and the control precision of the omni-axial movable nozzle through eliminating the coupling effects can be improved greatly by the method proposed in this paper. © 2016, Editorial Dept. of JSRT. All right reserved.
Liu X.-W.,Northwestern Polytechnical University |
Shi L.,Northwestern Polytechnical University |
Liu P.-J.,Northwestern Polytechnical University |
Qin F.,Northwestern Polytechnical University |
And 2 more authors.
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2017
The flow passage and combustion organization design of a DMSJ engine is carried out firstly.The specific impulse of the DSMJ engine is 1 029.6 s when M∞=4.0, whereas it is 899.9 s when M∞=6.0.A RBCC engine flow passage is obtained by placing a rocket engine on the isolation sidewall of the DMSJ engine.Investigation shows that the rocket shoulder and downstream flow passage scheme variation have limited influence on engine specific impulse when M∞ is lower.The RBCC engine specific impulse is 1052.8s when M∞=4.0, with the same fuel injection mode as the DMSJ engine.In order to gain a comparable specific impulse to that of DMSJ engine when M∞ is higher, the fuel injection mode of the RBCC engine should be different from the DMSJ engine.The combustion organization positions of two engines are both in the upstream flow passage when M∞ is elevated.The specific impulse of RBCC engine is 887.8 s when M∞=6.0, with the regulating of the fuel injection mode.Therefore, it is facile and feasible to design a RBCC engine based on traditional mature DMSJ engine. © 2017, Editorial Dept. of JSRT. All right reserved.
Wu J.,PLA Air Force Xian Flight Academy |
Liang C.,Xidian University |
Yuan H.,Xidian University |
Cao X.,PLA Air Force Aviation University
Xi'an Dianzi Keji Daxue Xuebao/Journal of Xidian University | Year: 2014
In order to solve computer memory limitation when computing the scattering characteristic of an electrically large target, the out-of-core adaptive cross approximation algorithm is designed. The adaptive cross approximation algorithm is used to compress the impedance matrix and reduce the computation complexity and storage effectively. By the use of the out-of-core technology, the memory space is reduced further and the calculating power of a single computer is raised by this method. The validity and effectiveness of the method are testified by numerical examples. lt is proved that the memory and computing time is reduced by this method when solving the radar cross section of a large target without losing the accuracy of the moment method.
Liu C.,PLA Air Force Aviation University |
Li Y.,PLA Air Force Aviation University |
Deng T.,PLA Air Force Xian Flight Academy |
Yuan G.,PLA Air Force Aviation University
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2015
A novel scheme of active fault tolerant control was proposed for the saturated nonlinear system with actuator fault. Considering the disturbances contained in the system, an adaptive fault tolerant controller was designed in this paper. First the control input was limited in the upper bound of saturation to make the control input avoid the saturation, and an adaptive fault tolerant controller combining fault estimation and adaptation law was provided. Then considering the control performance of robust and stability region, the H∞ control combind with Lyapunov theory was adopted to design the parameters of controller, meanwhile the set of invariance conditions was introduced to determine the largest ellipsoid stability region, then an issue of multi objectives optimization under linear matrix equalities constraints was put forward to realize the two control objectives. Finally an example was included to illustrate the control performance of adaptive controller compared with the fixed gain controller. The results show that the adaptive controller has better control performance which is more suitable for the fault tolerant controller design of saturated nonlinear system. © 2015, Huazhong University of Science and Technology. All right reserved.
Zhang Y.H.,Pla Air Force Xian Flight Academy |
Liu A.N.,Pla Air Force Xian Flight Academy |
Hao L.,Xian Communications Institute
Applied Mechanics and Materials | Year: 2014
This paper considers the factor of a mechanism based on customer, with the purpose of getting to know the different characteristics that must be taken into account during the development of software as a procedure. This also involves the attending of all kinds of relevant person of the Information system model together with the users’ message exchanging experience. This paper offers a mechanism of the related role in the design of a software component as a procedure, with the target of confirming their attending outside and within the organization. The purpose is to create a component centered on the user, involving clients and experts to work collaboratively; and get usable software as information system. © (2014) Trans Tech Publications, Switzerland.
Li Z.,Northwest Agriculture and Forestry University |
Zhang H.,Northwest Agriculture and Forestry University |
Song N.,PLA Air Force Xian Flight Academy |
Wang H.,Northwest Agriculture and Forestry University |
And 3 more authors.
Molecular and Cellular Probes | Year: 2014
MicroRNA (miRNA) plays an important role in modulating immune responses. We identified miR-15a-3p and miR-15b-3p which were immune related in bovine. Fourteen potential target genes were predicted. Both miR-15a-3p and miR-15b-3p showed significant differential expression patterns in healthy and mastitis infected cattle (P<0.01). Expression patterns of the two miRNAs provide important information on the relationships between mastitis and miRNA expression. © 2014 Elsevier Ltd.
Peng J.-L.,PLA Air Force xiAn Flight Academy |
Xi L.,Unit 94756 of PLA |
Jie L.,PLA Air Force xiAn Flight Academy
Proceedings of the 2015 27th Chinese Control and Decision Conference, CCDC 2015 | Year: 2015
For the problem of the traditional discrete optimal tracking differentiator (TD) with complex expressions and large phase delay, a more general and terse discrete optimal tracking differentiator without chattering is proposed. By introducing a phase adjusting gene, a new optimal control synthesis function is deduced. The phase characteristic of the tracking differentiator can be adjusted and the mathematic expression of the differentiator is terser. The traditional discrete optimal tracking differentiator is only an especial case of the new tracking differentiator (when the gene is equal to zero). The numerical simulation validated the effectiveness of the proposed approach. © 2015 IEEE.
Li P.,Xidian University |
Xu W.,Xidian University |
Qiu Y.,Xidian University |
Li H.,PLA Air Force Xian Flight Academy
Xi'an Dianzi Keji Daxue Xuebao/Journal of Xidian University | Year: 2013
For the problem that the dielectric sandwich radome will affect the electrical performance of the enclosed antenna, the main factors of the effect have been studied, and it is found that the main reason for the distortion of the far field pattern is the change of phase in the aperture due to radome. The relation between phase change and radome's structure has been analyzed. Then considering the structural features of reflector antenna, some compensated schemes for electrical performance have been proposed. One is the modification of the main reflector, the other is to adjust the axial offset focus of the feed. The second scheme is discussed because it can be more appropriately applied in engineering practice. A formula for the offset focus value has been proposed, and so has the restriction of application. Some simulations have been done by a 9.14 m dielectric sandwich radome of satellite earth station. The result shows that the compensated method of the axial offset focus is very effective, especially for the distortion of the far field pattern.
Chen Y.-X.,North University of China |
Chen Y.-X.,North China University of Technology |
Wu Q.-Z.,North University of China |
Zhao J.-H.,PLA Air Force Xian Flight Academy |
And 4 more authors.
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2013
The ultrasonic testing method is adopted to detect the defect of the alloy rocket body. The noise disturbance caused by water spraying can be effectively eliminated by using adaptive filtering for pretreatment. The system analysis theory was introdaued into ultrasonic defect testing, and effective characteristics of defect were extracted by deconvolution method. C-scan image can be obtained, based on which the existence of the defect and axial position of the defect can be intuitively seen, and the accurate positioning of the defect in the circumferential cross-section was achieved by the delay characteristics of the defect signal. The experimental results were compared with the X-ray test results, which shows that the ultrasonic testing method and signal processing technology can effectively and accurately detect the defect of the alloy rocket body, the technique can also be applied to defect detection of other cylindrical or conical object.
PubMed | Northwest Agriculture and Forestry University and PLA Air Force Xian Flight Academy
Type: Journal Article | Journal: Molecular and cellular probes | Year: 2014
MicroRNA (miRNA) plays an important role in modulating immune responses. We identified miR-15a-3p and miR-15b-3p which were immune related in bovine. Fourteen potential target genes were predicted. Both miR-15a-3p and miR-15b-3p showed significant differential expression patterns in healthy and mastitis infected cattle (P < 0.01). Expression patterns of the two miRNAs provide important information on the relationships between mastitis and miRNA expression.