The difficulties in the reconstruction of Zhang Heng’s Seismoscope come mainly from the lack of understanding of its mechanical principles. Such a discrepancy affects the rational reconstruction of the external form ...The difficulties in the reconstruction of Zhang Heng’s Seismoscope come mainly from the lack of understanding of its mechanical principles. Such a discrepancy affects the rational reconstruction of the external form of the seismoscope and the fair assessment of its position in science. In connection with the two basic conjectures on its basic principles over the past hundred years: namely, the suspended pendulum and the upright rod, the authors have conducted a comprehensive study from the viewpoint of modern seismology. In this study, various aspects are involved, such as the properties of the seismoscope, its description in the “History of the Latter Han Dynasty", the structure and movement of the central pillar, historical earthquakes in the Longxi region, earthquake intensity in Luoyang, and modern seismograms from the Luoyang seismic station. The result shows that Zhang Heng’s seismoscope works following a suspended pendulum principle; it is triggered to move by seismic Rayleigh waves; and resonance plays the role of amplification. The long-prevailing conjecture of the upright rod, which was mistakenly called the “inverted pendulum" for a time, is believed to be improper. Both theory and practice show that it cannot be used in a seismoscope and will lead to an irrational reconstruction of the external form.展开更多
This serial research has proposed the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit, to provide the constant output for the grid system, even at the suddenly fluctua...This serial research has proposed the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit, to provide the constant output for the grid system, even at the suddenly fluctuating/turbulent wind circumstance. In this paper, the tandem impellers prepared for the counter-rotating type pumping unit were operated at the turbine mode, and the performances and the flow conditions were investigated numerically with accompanying the experimental results. Even though providing the pumping unit for the turbine mode, the maximum hydraulic efficiency is close to one of the counter-rotating type hydroelectric unit designed exclusively for the turbine mode. Besides, the runners/impellers of the unit work evidently so as to coincide the angular momentum change through the front runners/impellers with that through the rear runners/impellers, namely to take the axial flow at not only the inlet but also the outlet, without the guide vanes. From these results, it can be concluded that this type unit is effective to work at not only the pumping but also the turbine modes.展开更多
文摘The difficulties in the reconstruction of Zhang Heng’s Seismoscope come mainly from the lack of understanding of its mechanical principles. Such a discrepancy affects the rational reconstruction of the external form of the seismoscope and the fair assessment of its position in science. In connection with the two basic conjectures on its basic principles over the past hundred years: namely, the suspended pendulum and the upright rod, the authors have conducted a comprehensive study from the viewpoint of modern seismology. In this study, various aspects are involved, such as the properties of the seismoscope, its description in the “History of the Latter Han Dynasty", the structure and movement of the central pillar, historical earthquakes in the Longxi region, earthquake intensity in Luoyang, and modern seismograms from the Luoyang seismic station. The result shows that Zhang Heng’s seismoscope works following a suspended pendulum principle; it is triggered to move by seismic Rayleigh waves; and resonance plays the role of amplification. The long-prevailing conjecture of the upright rod, which was mistakenly called the “inverted pendulum" for a time, is believed to be improper. Both theory and practice show that it cannot be used in a seismoscope and will lead to an irrational reconstruction of the external form.
文摘This serial research has proposed the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit, to provide the constant output for the grid system, even at the suddenly fluctuating/turbulent wind circumstance. In this paper, the tandem impellers prepared for the counter-rotating type pumping unit were operated at the turbine mode, and the performances and the flow conditions were investigated numerically with accompanying the experimental results. Even though providing the pumping unit for the turbine mode, the maximum hydraulic efficiency is close to one of the counter-rotating type hydroelectric unit designed exclusively for the turbine mode. Besides, the runners/impellers of the unit work evidently so as to coincide the angular momentum change through the front runners/impellers with that through the rear runners/impellers, namely to take the axial flow at not only the inlet but also the outlet, without the guide vanes. From these results, it can be concluded that this type unit is effective to work at not only the pumping but also the turbine modes.
