The influence factors experiment of poor contact discharge in indoor power grid
In order to achieve monitoring on poor contact in indoor power grid and avoid electrical fires, the discharge phenomenon caused by poor contact is experimented systematically. A discharge experiment model of poor contact is developed, in which the influence of the structural parameters of contact type and the gap distance on poor contact discharges are experimented, and the influence of the operating parameters of load type (cos φ), load current and voltage phase are experimented too. The influence factors of initial discharge and the influence regular patterns with various parameters have been obtained from a large number of experiments. Statistical results show that the discharge trend increases first and then decreases. In the range of experiment load, poor contact discharge is very sensitive to the structure parameters of contact model, in comparison, it is not sensitive to operation parameters such as load type and load current. When the phase of experiment-voltage is in the vicinity of 0°, 60°, 120°, 180°, 240°, 300°, it has intensive discharge region of poor contact, and this phenomenon has the similarity under different factors.
Recent advances on electrical contact resistance: Theory and experiment
Summary form only given. Electrical contact is important to thin film devices and integrated circuits, carbon nanotubes based cathodes and interconnects, field emitters, wire-array Z pinches, metal insulator-vacuum junctions, and high power microwave sources, etc. Because of the surface roughness on a microscopic scale, true contact between two pieces of conductors occurs only at the asperities of the two contacting surfaces, leading to contact resistance. For a long time, the basic model for contact resistance remains that of Holm's a-spot, where the current flows through a circular disk constriction of a small radius a and zero thickness at the bulk interface. In this paper, we vastly extend Holm's a-spot theory to higher dimensions, including dissimilar materials in the main current channels and in the connecting bridge joining them. Both Cartesian and cylindrical channels have been analyzed. A scaling law for the contact resistance has been constructed for arbitrary values of the dimensions of the channels and bridges, and for arbitrary electrical resistivity in each section. This scaling law was confirmed against spot checks with the MAXWELL 3D code. It also recovers the same results for all known cases, including connecting bridges of the same resistivity. This latter special case was also confirmed in our recent experiments.
THE RELIGIOUS SITES DURING THE CHINESE CULTURAL REVOLUTION, 1966-1976
This study presents a thought-provoking picture of statistical data regarding the growth patterns of the religious sites for five main Chinese religions during the Cultural Revolution from 1966 to 1976. Applying comparative and quantitative lenses, this paper addresses the diE™erent growth rates of religious sites during the four diE™erent periods from 1949 to 2004 to test the relative growth pace of religious sites during the Cultural Revolution. To understand the patterns of growing religious sites from 1966 to 1976, this study also compares the diE™erent growth rates of religious sites between the first phase (1966 to 1970) and the second phase (1971-1976) of the Cultural Revolution. Furthermore, it provides detailed information concerning the year of building new religious sites for all five major religions that hold more than 2,500 new religious sites during the Cultural Revolution. In addition, the study shows the top five provinces which built the most new religious sites while denoting their respective rural and urban locations in an eE™ort to demonstrate their geographical expansion during the period. Finally, this study addresses the growth rates of the national population and per capita GDP as compared to the growth of the religious sites during the period of national disaster (1966-1976).