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The airworthiness certification is an internationally accepted legal administrative act to ensure civil aviation safety, an important component of the core competitiveness of the national civil aviation industry, and an important force in promoting the healthy development of the civil aviation industry and the strategic transformation of the national economy. In this paper, the “three principles” model of airworthiness certification is proposed, aiming at compliance of technical standards for airworthiness certification, differences in airworthiness management standards, and acceptability of airworthiness certification results among countries. Through an in-depth analysis of the concept, model, and practice of the “three principles” of airworthiness certification, the theoretical connotation of the “three principles” relationship of airworthiness certification is revealed, and the relationship model between the “three principles” of airworthiness certification is established. The study of this model can guide the international cooperation on airworthiness and the construction of airworthiness regulatory system. In addition, the effectiveness of the “three principles” model has been verified in airworthiness certification practice. Through the research on “three principles” of airworthiness certification, we can continuously improve the compliance of technical standards, narrow the differences in management standards, and ensure that the certification results are widely accepted by the international community. This will enhance the international discourse and influence of China’s civil aviation airworthiness certification, and create a fairer international policy environment to facilitate the development, expansion and internationalization of China’s civil aviation industry. [ABSTRACT FROM AUTHOR]

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In the drag parachute test, especially during the process of high-speed rocket sled drag parachute test, due to the nonsteady motion of the drag parachute system with a variable acceleration and the influence of wake field in the anterior body, the existing drag parachute test data analysis methods are often difficult to accurately calculate the drag coefficient. In view of the unsteady and wake interference characteristics of the drag parachute test, this paper starts from the dynamic theory of the drag parachute, and theoretically analyzes the additional mass and wake field characteristics of the drag parachute during the unsteady motion. The drag parachute coefficient correction model of the drag parachute system is established by using nonsteady correction and dynamic pressure correction methods. On this basis, the test results of a certain type of cross-shaped single umbrella and cross-shaped double umbrella models are analyzed, the corresponding nonsteady correction coefficients and dynamic pressure correction coefficients are determined, and the cross-shaped single and double umbrella resistance coefficient correction models are established. The results of correction models are compared with wind tunnel tests and traditional calculation methods. The results show that for the single parachute model, the calculation result error can be reduced from the original 27% to less than 9% by the new correction model, and for the double umbrella model, the calculation result error from the original 30% to less than 7%. In this paper, based on the analyses of added mass, the drag coefficient correction method can calculate the drag coefficient of the drag parachute more accurately, so as to provide a more accurate calculation method for the correction of the drag parachute test data. [ABSTRACT FROM AUTHOR]

Numerical methods are used to study the aerodynamic characteristics of different airfoils in ground effect at subsonic velocity. Taking Ma as 0.5 as the flow condition，the effects of airfoil parameters and flight height on aerodynamic characteristics are studied. The calculation results show that in the case of ground effect with Ma of 0.5 and angle of attack of 6°，reducing the airfoil curvature is easier to generate shock wave drag at the leading edge of the airfoil. Increasing the trailing edge curvature of the lower surface will increase the pressure on the trailing edge，the lift coefficient and the nose down pitching moment increase accordingly. As the flying height decreases，the ground effect enhances，the pressure on the lower surface of the airfoil increases，and the lift increase on the lower surface is greater than the suction loss on the upper surface. The wing lift coefficient and lift-to-drag ratio increase more and more significantly [ABSTRACT FROM AUTHOR]

Effects of SiO32- in natural source water on phosphate removal by FeSO4 / KMnO4 process are investigated. The removal efficiency of phosphate increases firstly and decreases subsequently with the increase of pH values in the presence of SiO32- . The present of SiO32-（1.0 mmol/L）promotes the efficiency of phosphate removal in pH values of 4―6 and removal of phosphate enhances by 6.0%，9.9% and 6.3%. In contrast，with the increase of pH values（7―9），removal of phosphate significantly decreases by 14.76%， 32.6% and 17.3%. SiO32- reduces the surface ζ potential of floc particles formed in situ and increases the amount of residual iron in the solution. In addition，SiO32- has a certain influence on composed elements and surface features for floc particles formed the KMnO4 / FeSO4 process. The results provide a necessary theoretical foundation for the practical application of KMnO4/FeSO4 process for phosphate removal. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) flow field around a rocket sled system in low subsonic testing velocities was simulated through 3D incompressible Navier-Stokes equations and the Realizable k-ε turbulence model. The wake flow characteristics of the rocket sled with and without the extension plate were obtained at different free stream velocities. Moreover, the difference of the wake flow fields were compared and analyzed between the rocket sled and the aircraft. Results show that the dynamic drag is about 4.8%~8.6% of the total weight of the rocket sled system corresponding to a drag coefficient about 0.65 for the free stream velocities in the range of 60 m/s to 90 m/s. The aerodynamic lift force, which is negative, is merely 0.84%~1.9% of the total weight, and the lift coefficient is just -0.005, suggesting that the effect of the aerodynamic lift can be omitted in the kinetic analysis of this rocket sled system. The dimensionless velocity difference in the detection location is less than 8%, and the dimensionless pressure difference is less than 0.5%. These differences indicate that the influence of the velocity on the wake flow field can be neglected. In addition, the wake flow fields are similar according to the comparison of the wake field between the rocket sled system and the aircraft. This similarity satisfies the requirement of the experimental test. [ABSTRACT FROM AUTHOR]

This paper designs a kind of intelligent tracking the material car based on MSP430, and introduces the material handling methods. Microcontroller outputs PWM signal to control the car motor running, so as to control the path of the car by using TCR.T5000 test road information and feeding hack to the microcontroller. As reaching the finish line, the car waits for unloading. Alter completion of discharge, it returns to the starling point to charge, so as to realize the purpose of the car tracking and delivery. We can also make the car run by infrared remote control. Test results show that the circuit of the whole system has simple structure, high reliability and the car runs agilely and conveniently. Finally, we realize the expected functions of the smart car tracking and sniping the material. [ABSTRACT FROM AUTHOR]

To research the airborne liquid cooling system, this paper uses software Simulink to build the mathematical model of each component in the single-branch series connection system and multi-branch parallel connection system. The characteristics of systems are compared and analyzed. PID control is used for branch flow regulation in multi--branch system, and the dynamic simulation of multi-branch system is subsequently performed under given conditions. Moreover, the influence of avionics operating condition, flight altitude and flight Maher number on the system is analyzed. The result shows that the flow resistance of multi-branch system is lower, the flow of each branch is carried out according to the thermal load of the electronic equipment in different working conditions in multi-branch system, and a lower flight altitude or a larger flight Mach number will lead to a higher temperature of system. [ABSTRACT FROM AUTHOR]

Traffic flow prediction is a very important research area of intelligent transportation system, and has a very important academic value and practical significance to improve the traffic congestion problems. Traditional prediction methods which used determined mathematical model would not meet the needs of prediction accuracy and convergence speed during the traffic management control because of nonlinear, complexity and uncertainty of traffic flow. In order to forecast traffic flow accurately, real-timely and efficiently, a new algorithm is proposed by combining wavelet theory and neural network, and constructing an IWNN( improved wavelet neural network) with improved network training methods. At the same time, the initial weights are optimized by GA ( genetic algorithm). It can improve prediction accuracy, speed up the convergence speed and avoid entering local minima. The simulation results show that it can get better prediction results. [ABSTRACT FROM AUTHOR]

Unstable video images caused by camera jittering will lead to inaccurate or error detection results. Aiming at this problem, a motion compensation scheme is proposed by combining wavelet transform and adaptive SIFT algoritlim. First, the wavelet transform based on threshold is applied to remove noise of the image, the iterative criterion of variable step is established to adaptively search the matched SIFT key points, the match of features obtained is much more precisely. Then the jitter parameter is estimated by analyzing offset of these matched points. Finally, the Gaussian mixture models combined with wavelet transform are employed to detect moving target. Compared with the similar algorithm, the proposed method can obtain more precise and stable matched feature points such that the effective estimation of jitter parameters is assured. It can solve the jitter effectively and detect the moving target precisely and efficiently. [ABSTRACT FROM AUTHOR]

This paper presents the design and implementation of an IR-learning remote automatic monitoring, alarm and control system which has intelligence and universality for the laboratory environment, and can help to ensure lab safety. The system combines the theories of IR waveform storage and closed-loop control based on MSP430, STC15 and GSM , includes a closed-loop automatic control subsystem, and has the functions of remote monitoring and control. It has the ability to learn, store, reproduce, and transmit IR signals and to control all kinds of appliances that can be controlled by IR. In this paper, the principles and functions of the system, and hardware and software design are introduced, and the test results are described. The experimental results indicate that this system achieves the expected goals. The system can be applied to other occasions after the functions are modified and extended, so it has a certain research and practical value. [ABSTRACT FROM AUTHOR]