Overlying strata movement of recovering standing pillars with solid backfilling by physical simulation

To analyze the overlying strata movement law of recovering room mining standing pillars with solid backfilling.Physical simulation experiments with sponge and wood as the backfilling simulation material were tested.The results show that:(i) The covering-rock mechanics of the overly strata comes from "two-arch structures + hinged girder + bend beam" to "backfilling material + hinged girder + bent beam" by increasing the fill ratio from 0%to 85%,the beginning of overlying strata movement appears later and the total duration of subsidence velocity increased from zero to the highest value increases.The trend of "single polarization" of the subsidence velocity curves becomes noticeable and the velocity variation trend becomes stable,(ii) The equiponderate aeolian sand was added to improve the anti-pressure ability of the loess,and the corresponding ground processing & transportation system was designed.

Physical Simulation of Nonmetallic Particle Movement in Al Melt under Electromagnetic Field

Physical simulation is used to study the movement of nonmetallic particles in Al melt in electro- magnetic field. It is found that the terminal velocity of particles in different Reynolds number range has different functions. By confirming drag force coefficient of nonmetallic particles with Reynolds number in the range of 0.2-10 and 10-25 respectively, two functions of terminal ve- locity for spherical nonmetallic particles have been got accordingly, which provide a theoretical basis for separating nonmetallic inclusions from Al melt in electromagnetic field.

The Reality and Application of Yin and Yang

Ancient Chinese philosophers discovered Yin and Yang and the laws of Yin and Yang movement during their exploration and practice of nature more than two thousand years ago, and applied them to life, science, philosophy and medicine, playing an important role in the achievement of ancient Chinese civilization. Through historical changes, yin and yang have gradually been regarded as a concept or theory, thus making it difficult for people to understand the connotation of Yin-Yang and make new discoveries and progress. Nowadays, many scholars in China and the West are interested in studying the treasures of ancient Chinese civilization. We illustrate the actual function of Yin and Yang by explaining the essential state of matter, the law of physical movement, the transformation of energy, and then illustrate the practical application in life and science. In conclusion, yin-yang is a key to unlocking the treasures of traditional Chinese civilization, which can help to bring into play its original values, and continue to provide new insights and directions for the development of modern science and the advancement of humanities.