Abstract:The unbalanced quantity of highspeed rotating micro turbojet engine in rotor system has especially effects on working state of the rotor. On the premise that gyro is effective, the variations of bearing dynamical reaction in the micro turbojet engine with the rotating speed and unbalanced quantity distribution azimuth angle are studied by using harmonic response analysis method. The results show that the greater the rotating speed is, the greater the bearing dynamical reaction, and the influence of the magnitude of unbalanced quantity on bearing dynamical reaction is greater than that of rotating speed. The bearing dynamic reactions in the position of compressor and turbine are of maximum and minimum at unbalanced quantity distribution azimuth angle of 180° respectively. The results of analysis provide an important reference for decreasing the vibration problem of engine and avoiding bearing damage caused by unbalanced quantity.

Abstract:The supersonic flow (Ma=2.0) past several types of microramps is simulated by the numerical simulation method to improve the characteristics of isolator. The result follows that with the increase of the width at the trailing edge of MVGs, the length of the shock train becomes shorter, and the position of pressure leading edge moves backward. Meanwhile, the spanwise distance of streamwise vortices generated by entirety type MVGs is closer than that of the separated, but the distance to the bottom wall is farther. And the result also indicates that the momentum can be delivered to boundary layer in short distance to improve the flow condition. MVGs with wide back width can reduce total pressure skewness and is superior to the basic model.

Abstract:The accurate power prediction of actuator plays an important role in electric energy management. In order to improve the prediction accuracy in actuator system, an improved multivariable grey neural network model is established. Taken this aspect of the relative factors of producing a great impact on the needs of power in system into account, the PCA is used to extract the comprehensive variables as an input of the prediction model. By so doing, this effectively reduces the dimension on the basis of the accuracy of prediction. In the process of selecting the initial values and background values by utilizing the incremental method, the PSO is used to calculate the optimal background value to improve the prediction accuracy to a large degree. In addition, taken this aspect of the influence matter on sequence fluctuation into account, a BP neural network model is established to correct the error in the prediction value. The results show that the model is valid and advantageous to the energy dispatching of aircraft.

Abstract:In order to overcome the influence of various disturbance factors and to improve the control effect in the process of glide and flight, an optimal control method for nonlinear stochastic systems is studied. Based on the general control principle of rocket projectiles flight process, a differential form of attitude dynamics model is established. Taking attack angle and yaw angle as observation variables, and rudder reflection angles as control variables, the state equations, the objective function and the control law are deduced. The detailed expression of the adjoint function is put forward. The optimal filter is designed based on the Riccati equation. Control parameter is designed and simulation analysis is carried out with spread glide control point as the feature point. The simulation results show that this controller system responds quickly and has a good control quality.

Abstract:Aimed at the problem that maneuvering targets intercepted by interceptor at out of atmosphere are uncertain at endgame guidance, this paper presents a design method based on threedimensional endgame guidance law. The paper establishes a relative motion equation with respect to the line of sight between target and interceptor by adopting a robust guidance law with sliding mode control theory, and designs a guidance law to make the line of sight angular rates in elevation and azimuth engagement planes tend towards zero respectively. The paper integrates the supertwisting sliding mode disturbance observers (SMDO) into the guidance law to compensate uncertainties such as target maneuvers, thus reducing the required switching gains in the guidance law significantly. The simulation results indicate that the proposed sliding mode guidance law is high in guidance accuracy and is good in robustness to maneuvering target.

Abstract:Aimed at the problem of cruise missile path planning，a Competition Quantum Evolutionary Algorithm (CQEA) is proposed in this paper. The algorithm is a kind of optimum solution through two direction evolution and selfadapting variation to avoid to land itself into the local. Meanwhile, for the realtime request of path replanning, surface of minimum risk and search vertical bar are reduced to decline the dimension of the primary 3dimensional space. The initial population is obtained through an idea of operational area cluster to guarantee its noninferiority. The simulation results show that compared to PAQEA, CQEA is good in searching efficiency. And compared to 3dimensional space, CQEA is good in performance in the new searching space.

Abstract:Thermal fatigue is a major source of failure of solder joints in surface mount electronic components. Through analyzing and summarizing the leadfree solder joint thermal reliability at home and abroad, this paper emphatically expounds the influence of the solder Ag content, thermal cycle parameters and solder joint microstructure on the thermal reliability of leadfree solder joints. Finally, the paper analyzes the challenges and the developing trend of the leadfree solder joint thermal reliability. The hotspot and challenges in the future research by microstructure analysis and modeling, the influence of thermal load analysis and the construction of physical failure model of solder joint, etc. are going to be researched further.

Abstract:Airborne early warning radar towing infrared search and tracking system for detection is a kind of important working mode of multisensors coordination on the same platform. In order to try to find out about the quantitatively evaluative patterns influence on the IRST's detective efficiency, taking the detecting probability of the IRST as an evaluation criteria, this paper establishes a mathematic model of the successful towing probability under condition of multiinstantaneous field of views, calculates the view zones searched to meet the needs of a certain successful towing probability under condition of the different radar working modes, and then derives the relationship formulas among the detection probabilities, the operating distances, and the pulse accumulations. Under the premise of ensuring that the successful towing probability is 0.99, the radar in high precision measurement mode can acquire the best towing effect to make the search area of IRST reduce to 1/180 of the original, the time saving efficiency is 99.4%, and the process of target capture accelerates. The saved time can use to accumulate pulses, the detective probability corresponding to the maximum action distance increases from 0.5 to 0.985 3 when the accumulated number of pulses reaches two pulses, thus significantly improving the detective efficiency of IRST.

Abstract:Aimed at the problem that the reconnaissance receiver easily detects the information in direction of the conventional phased array radar and jams, an angle deception method based on FDA (Frequency Diverse Array) is proposed. This paper applies a small linear frequency shift is applied from channeltochannel, resulting in FDA pattern function related with range between channels to make electromagnetic wave power bend in different ranges, thus forming a virtual radiation source, and achieving the goal of angle deception aimed at reconnaissance receiver. In addition, based on the analysis of deception principle, the paper discusses the deception effects of frequency offset and space between channels. The results of Matlab simulation show that by this method the angle deception can reach up to 90 degrees at specific ranges when some factors are properly fixed.

Abstract:Aimed at the problem that a singleplatform is hard to perform the continuous detection and stable tracking of near space hypersonic vehicle, a cooperative detection and tracking model is structured based on multiplatform. The spacenear spaceairground/sea cooperative detection system is put forward, the construction, time scheme and detection process are analyzed according to analysis of the combat characteristics and detection demands of NSHV. The cooperative detection platform is built up, and the static deploying and dynamic target detecting effect are analyzed by STK. The advantages of detection range and timeliness are verified with the simulation results, and these advantages make up the weakness of the single platform effectively. This will supply detecting and tracking this target in the future with an important technology foundation.

Abstract:The emitter and threat level evaluation can provide a basis for configuring jamming resources and mission of assignment, and is a vital research subject of the airborne active self-defense electronic countermeasure. Aimed at the problems that the assessment indexes are few and incomprehensive, this paper establishes an emitter-threat assessment system to the needs of effect on the distance estimation index, resolution estimation index, probability estimation index and platform index. The paper calculates each index through parameter set. Then, the paper uses the grey correlation based on the entropy weight to figure out the optimal correlation degree. Finally, the paper judges the threat level by comprehensive relative closeness coefficient. The simulation example shows that though analyzing the result and comparing the method among other three methods, the merits prove the effectiveness and the feasibility of the method.

Abstract:Aimed at the problems that the description of importance analysis is complex, abstract conception is uncertain, and these are unfavorable ordering for fuzzy fault tree analysis, a new importance analysis method based on structure vector is proposed. First of all, the trapezoid fuzzy number is abstracted as uniformity trapezoid and its change is abstracted as the shifty vector of the trapezoid center. And then, the horizontal mapping of shifty vector is used to define the variation of error rate and vary rate of error rate. Meanwhile, the vertical mapping of shifty vector is used to define the irresolute degree of trapezoid fuzzy number. At last, the fault of cooling system of a certain radar is treated as the top event, and the method proposed is proved by importance analysis.

Abstract:In 'INTERNET + TIME', cloud computing represents a novel business model. However, the cloud user tasks in the system and compute node scheduling problem significantly affects the system performance and competitiveness of cloud. An improved algorithm of quantum particlesadaptive quantum particle swarm optimization (RAQPSO), based on the inertia weight adjustment of parameters and reverse learning to improve the global search ability of the algorithm, and applied to cloud computing resource scheduling problem to verify the effectiveness of the algorithm. With cloud computing resource scheduling model is established. And then uses the adaptive mechanism, the change of the fitness function as update of inertia weight factor, avoids simply value according to the linear function of the number of iterations. Add the particle reverse learning operator, to strengthen the global search ability particles. The experimental results show that the RAQPSO algorithm greatly save the task completion time, and keep a good computing nodes load balancing.

Abstract:Transmission control technique influence communication performance in aviation network. The transmission control mechanism based on priority guarantee performance of high priority business, but arise poor transmission performance of low priority business and bandwidth utilization problem. For alleviate this problem, put forward the innovative "cognitive available bandwidth" concept and design the transition and control mechanism of cognitive available bandwidth through combined with the theory of green communication and the available bandwidth estimation techniques; and selfadaptive modulation is applied to improve bandwidth utilization rate. The simulation results prove that the low priority service performance is relieved based on guarantee performance of high priority service and achieve the delay shake is less than 0.02 ms through the use of transition and control mechanism of cognitive available bandwidth. The throughput rate is improved 3.26% by using selfadaptive modulation technique.

Abstract:According to the characteristics of network model and message model in time-triggered ethernet，a rate monotonic scheduling (RMS) based timetriggered communication table generation algorithm is improved，which is used to generate configurable communication schedule in the timetriggered network．The improved timetriggered RMS (TT-RMS) algorithm can be used to calculate the scheduling of message timeslots based on the periods of messages, determine orders of messages transmission in accordance with the message period and routing links, and make scheduling messages by timeslots．The experiment results show that the improved TT-RMS algorithm can generate communication table according to the multi-hop networks and messages with different size and period, and at the same time the communication table can also meet the needs of the deadline requirement of messages.

Abstract:In order to prevent failure condition from spreading, and avoid the phenomenon of network collapse effectively under the influence of propagation effect of node failure, this paper proposes a model of modified betweenness, defines initial load by controllable coefficient α, and then describes a relatively good point α=0.6 by using the theory of degree and betweenness. Through modeling on scalefree network, the paper can draw a simulation conclusion by comparing the nodes under the conditions ofα＜0.6with α＞0.6 subjected to attack. The simulation result shows that the node whose initial load point is low is subjected to attack, and its survivability of corresponding network is stronger than that of the node whose initial load is high under the conditions of α＜0.6. The result is opposite under the conditions of α＞0.6. But at the conditions of α=0.6, the survivability is comparatively good whatever what kind of node is subjected to attack. The result shows that the viability and the survivability can increase and improve furthest by controlling the coefficient of α＞0.6 neighborly in real network planning.

Abstract:Aimed at the problems that slow convergence speed, poor learning performance and other imperfections exist in the classical BP neural network intrusion detection, a PCABP neural network intrusion detection method is put forward by adopting principal components analysis and additional momentum method, This method improves the classical BP neural network algorithm by data features selection and network weights amendment. Firstly, the paper standardizes the network data set, and then adopts it to deal with dimension reduction to confirm the characteristics. Finally, the paper detects the processed data set by improved BP neural network. Through the lots of experiments in KDD Cup 1999 network data sets, the result shows that the method has better performances in system model convergence, detection efficiency and detection accuracy in most network environment. Especially, in training samples, the convergence of system model, the detection efficiency and the detection accuracy are better than that by using BP neural network algorithm and halfsupervision intrusion detection algorithm.

Abstract:This paper, taking FeCl3·6H2O and CH3COONa as source materials, prepares Fe3O4 powders by hydrothermal method to compare the superior of absorption with solid Fe3O4 powders. The paper analyzes the crystal structure of Fe3O4 powders by X-ray diffraction (XRD), and the size and the morphology of the prepared products by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The paper tests the electromagnetic parameters of coaxial samples by network analyzer to obtain the microwave absorption of porous Fe3O4 powders. The results indicate that the density of porous Fe3O4 powders is lower than that of the solid Fe3O4 powders, and the real part of permittivity of porous Fe3O4 powders is absolutely higher. When the thickness of samples is thicker than 4 mm, the absorption of prepared porous Fe3O4 powders is definitely superior.

Abstract:Takingtetrabutyl titanate as Ti source, this paper synthesizes the different metal-N' codoped TiO2 nano powder by sol-gel method, and compares the effects of alcohol’ amount on phthalic acid ester hydrolysis. The photocatalytic activity and size of doped TiO2 powder are characterized by ultravioletvisible absorption spectroscopy (UV-Vis) and X-ray diffraction (XRD). The result shows that the gel time in turn increases with the increase of tetrabutyl titanate butyl and anhydrous ethanol volume ratio. The single metal doped light catalyst activity is stronger than that of various metals. Compared with Mn2+,Cu2+，Fe3+,Al3+,Ba2+,Co2+ and Fe3+，Co2+ and N-Co doped TiO2 powder is the most active under condition of visible-light.