THEORETICAL ANALYSIS AND EXPERIMENTAL VERIFICATION ON TERNARY-WAVES METHOD TO COMPILE ACCELERATED SPECTRA

The equivalent damage calculation formulae of fatigue crack formation andgrowth are established. In order to compile the fatigue crack formation and growth accelerated loadspectra, the main wave shapes and load sequence of the actual load spectrum are kept constant, andthe carrier waves are cut off. And secondary waves are put together into new secondary waves toshorten the test time according to the equivalent damage calculation formulae respectively. Then bythe fatigue cumulative damage calculation of the fatigue crack formation and growth accelerated loadspectra, the one corresponding to the bigger damage is determined as the fatigue accelerated testload spectrum. Therefore in the test process, the fatigue accelerated test spectrum may be appliedtill fatigue failure, the engineering fatigue crack length of full-scale structure need not beinspected, and the fatigue crack formation accelerated load spectrum need not be transferred intothe fatigue crack growth accelerated load spectrum. Finally, it is verified by tests of two kinds ofspecimens that the damages of the specimens caused by the accelerated load spectra are near tothose by the actual load spectra; namely, the tested life of actual load spectra is similar to thatof accelerated load spectra. But the test time of accelerated load spectra is shortened by aboutthree-quarters that of actual load spectra. From these tests, it is also found that the fatigueaccelerated test spectrum has an advantage over FALSTAFF spectra.

A new optimization algorithm based on chaos

In this article, some methods are proposed for enhancing the converging velocity of the COA (chaos optimization algorithm) based on using carrier wave two times, which can greatly increase the speed and efficiency of the first carrier wave’s search for the optimal point in implementing the sophisticated searching during the second carrier wave is faster and more accurate. In addition, the concept of using the carrier wave three times is proposed and put into practice to tackle the multi-variables opti- mization problems, where the searching for the optimal point of the last several variables is frequently worse than the first several ones.

Electromagnetic Analysis and Optimization of High-speed Maglev Linear Synchronous Motor Based on Field-circuit Coupling

High speed maglev train has become a new non-contact transportation mode mainly studied in recent years because of its non-sticking and high speed characteristics.Firstly,the finite element model of the long stator linear synchronous motor(LSM)is established based on the structure of the test prototype.After calculation,it is compared with the experimental data and verified.On this basis,a field-circuit coupling model based on inverter circuit is established,and the influence of carrier wave ratio change on the output characteristics of LSM is calculated and analyzed.Finally,the filter circuit is introduced into the field-circuit coupling model,and the influence of the filter circuit on the output characteristics of the LSM is compared and analyzed.

Determination of Vessel Attitudes Using GPS

With the development of GPS carrier wave phase technology, it becomes possible that the height accuracy of centimeter level is got by GPS RTK technology. Vessel attitudes are very important parameters in marine survey. In this paper, they were determined by 4 GPS receivers. At the same time, the arithmetic and procedure of vessel attitude determining were given. Based on an experiment, some useful conclusions were obtained and the corresponding methods were put forward to improve the accuracy.

Dynamical study on charge injection and transport in a metal/polythiophene/metal structure

The dynamical process of charge injection from metal electrode to a nondegenerate polymer in a metal/polythiophene （PT）/metal structure has been investigated by using a nonadiabatic dynamic approach. It is found that the injected charges form wave packets due to the strong electron-lattice interaction in PT. We demonstrate that the dynamical formation of the wave packet sensitively depends on the strength of applied voltage, the electric field, and the contact between PT and electrode. At a strength of the electric field more than 3.0 × 10^4 V/cm, the carriers can be ejected from the PT into the right electrode. At an electric field more than 3.0 × 10^5 V/cm, the wave packet cannot form while it moves rapidly to the right PT/metal interface. It is shown that the ejected quantity of charge is noninteger.

A BRIEF REVIEW AND PROSPECT OF EXPERIMENTAL SOLID MECHANICS IN CHINA

In this review, acritical look at the research progress ofexperimentalsolid mechanics in China for the past years is presented. Issues are discussed of the discovery and development of new fundamental methods and techniques versus performance benchmarking for many of their applications. Included herein are photoelasticity and various forms of modern photomechanics, acoustical techniques, image processing and videometrics, radial and spectrum techniques, and experimental mechanics on micro/nano scale. It is also noticed that both the ever developed instrumentation and specialized synthetical techniques have played important roles in advancing experimental mechanics in scientific researches and industrial applications. Finally, an attempt is made to look into the future of experimental solid mechanics with personal opinions offered on what the future trends will be for the researches in the field.

Literature Review on Wireless Sensing Wi-Fi Signal-Based Recognition of Human Activities

With the rapid development and wide deployment of wireless technology, Wi-Fi signals have no longer been confined to the Internet as a communication medium. Wi-Fi signals will be modulated again by human actions when propagating indoors, carrying rich human body state information. Therefore, a novel wireless sensing technology is gradually emerging that can realize gesture recognition, human daily activity detection, identification,indoor localization and human body tracking, vital signs detection, imaging, and emotional recognition by extracting effective feature information about human actions from Wi-Fi signals. Researchers mainly use channel state information or frequency modulated carrier wave in their current implementation schemes of wireless sensing technology, called "Walls have eyes", and these schemes cover radio-frequency technology, signal processing technology, and machine learning. These available wireless sensing systems can be used in many applications such as smart home, medical health care, search-and-rescue, security, and with the high precision and passively device-free through-wall detection function. This paper elaborates the research actuality and summarizes each system structure and the basic principles of various wireless sensing applications in detail. Meanwhile, two popular implementation schemes are analyzed. In addition, the future diversely application prospects of wireless sensing systems are presented.