Papers by Keyword: Scale Factor

Abstract: Capillary tree networks can be efficiently used for several applications. These trees display the same patterns at different levels of scale, which is a property found in fractal objects. This paper combines a thermodynamic formulation with the geometric characteristics of the tree fractal network, to describe the equilibrium capillary pressure. The model proposed here accounts for, in addition to physical properties of the fluids, the fractal dimension, the scale factor between the size of parent and daughter tubes, and the branching level. The effect of each of these properties on the capillary pressure is also investigated.

Abstract: Theoretical and practical aspects of fabrication and processing of bulk metallic nanomaterials are presented. The effect of different deformation modes on the structure formation is shown. Development of nanotechnology with respect to fabrication of gas turbine engines (GTE) parts made of nanostructured superalloys is exemplified.

Abstract: Thermophysical model of liquid-steam stream compressor, results of analysis of experimental researches of boiling up streams of liquid in the broadening ducting and running part of liquid-steam stream compressor, description of forming of three critical modes of flow and structural inversion of stream are presented in this article. The mathematical model of working process which allows to determine parameters and characteristics of liquid-steam stream compressor is presented.

Abstract: The effects of temperature variation on the system performance is discussed in this paper. The temperature characteristic of the natural frequency and quality factor is analyzed theoretically firstly. Then the simulation models of the open-loop drive system, the closed-loop drive system, the closed-loop sense system and the quadrature correction system are constructed to simulate the temperature characteristic of the scale factor and zero bias. The simulation results demonstrate the relative change of the scale factor in the closed-loop drive system, that is 1.35%, almost decreases by 67 times relative to the open-loop drive system and the variation of the zero bias in the closed-loop drive system, that is 0.2789°/s, almost decreases by 364 times relative to the open-loop drive system. At the same time, the relative change of the scale factor in the closed-loop sense system, that is 0.000029%, almost decreases by 46551 times relative to the closed-loop drive system. The variation of the zero bias in the closed-loop sense system, that is 1.2×10^-11°/s, almost decreases by 2.3×10¹⁰ times relative to the closed-loop drive system, which shows the proposed method is feasible and correct.

Abstract: Aiming at deficiency of fractal image compression, encoding time length and large amount of calculation, an improved algorithm of fractal compression is proposed based on the average deviation. First,divided image into blocks by using the characteristics of the average deviation, then determined the image block matching constraints by the application of the scale factor to simplify the calculation method, and finally limited the search range with the constraints, thus decrease the amount of the search range, improve the efficiency of the domain block matching. The simulation results show that the improved algorithm can reduce the computation of block matching, and improve the fractal image coding efficiency.

Abstract: In order to realize the guidance and control of the flight system, we focused on the study of different guidance instructions extraction methods and system stability control problems with respect to the characteristics of full-strapdown optical imaging seeker. First, we established the model of strapdown optical imaging seeker and introduced the definition of scale factor and the theoretical compute formula. Then the full field of view accuracy of full-strapdown optical imaging seeker was gained through the experiment and the validity of the scale factor definition has been tested and verified. Finally, we analyzed the system stabilities of different guidance instructions extraction methods. The results showed that if we applied the line of sight angular rate (LOS angular rate) to the system, the scale factor error was 5% when the free-running frequency of the overload autopilot was 20rad/s, and the scale factor error was 8.4% when the free-running frequency was 10rad/s. And if we applied the line of sight angle (LOS angle) to the system, the scale factor error was 33.3%, irrelevant to the free-running frequency. This analysis laid a foundation of guidance application..

Abstract: Resonant micro-accelerometers have good properties such as the large dynamic range, the high sensitivity, the strong anti-interference ability as well as the direct digital output. A new z-axis resonant micro-accelerometer based on electrostatic stiffness is researched. The new z-axis resonant micro-accelerometer consists of a torsional accelerometer and two plane resonators. The sensing movement of the accelerometer is decoupled with oscillation of the plane resonators by electrostatic stiffness, which will benefit to improve the performance of the new z-axis resonant micro-accelerometer. The new structure is designed. The sensitive theory of the acceleration is investigated and the equation of scale factor is deduced under ideal conditions. The simulation is implemented to verify the basic principle by the Ansys and Matlab. The structure simulation results prove that the effective frequency of the torsional accelerometer and the resonator are 0.66kHz and 13.3kHz separately. And the interference modes are isolated with the effective mode apparently. The system simulation results indicate that the scale factor is 37Hz/g and the system has excellent capabilities in locking and tracking natural frequency of resonators, which proves that the basic theory is feasible.

Abstract: Mounting accuracy is of great importance to the performance of the Doppler-based navigation techniques. In this paper, a novel method for alignment calibration of IMU and Doppler sensors is presented. The presented scheme is based on the information from INS/GPS integration and Doppler. Different from previously reported techniques, not only the misalignments but also the scale factor error is considered in this study. By using a Kalman filter, the alignment matrix which is consisted of a misalignment matrix multiplying with a scale factor is estimated. The performance of the alignment estimates is evaluated with field experimental data over Yangzi River. Experimental results shown the estimates obtained by the proposed method perform much better than the existing solution. By using the proposed method, the accuracies of the transformed velocity and positioning are both increased.

Abstract: In order to solve the problem that in the dual axle rotating modulation inertial navigation system the angle between the horizon roller of the system and horizontal plane can't be removed, this paper provides an on-line self calibration method based on inertial navigation system, and this method realized the on-line self calibration of the inertial navigation system by calculating bias and scale factor both of the gyroscope and accelerometer, solving the problem that in the dual axle rotating modulation inertial navigation system the angle between the horizon roller of the system and horizontal plane can't be removed, providing an calculable basis for the prediction of attitude angle and realizing on-line autonomous self-calibration.

Abstract: This article has introduced and evaluated the various methods of study on carbon emissions, and makes a comparison on the research conclusion by using these methods. We has classified the influence factors of carbon emissions into three primary factors such as technical factor, structure factor and scale factor, respectively including six secondary factors such as carbon emission intensity and energy intensity; energy structure and industrial structure; economic scale, population size.