Newton’s theory of gravitation has been outdated by relativity theory explaining specific phenomena like perihelion precession of Mercury, light deflection and very recently the detection of gravitational waves. But ...Newton’s theory of gravitation has been outdated by relativity theory explaining specific phenomena like perihelion precession of Mercury, light deflection and very recently the detection of gravitational waves. But the disappearance of the obvious gravitational force and the variation of time are arguable concepts difficult to directly prove. Present methodology is based on hypotheses as expressed in a previous article: a universal time and an inertial mass variable according to the Lorentz factor (which could not be envisioned at Newton’s age). Because this methodology is mainly stood on Newtonian mechanics, it will be called neo-Newtonian mechanics. This theory is in coherence with the time of the Quantum Mechanics. In Newtonian mechanics, all forces, including gravitational force, are deducted from the linear momentum. Introducing the variable inertial mass, the result of the demonstration is an updated expression of the net force at high velocity: F = γ<sup>3</sup>m<sub>g</sub>a. If such a factor in γ<sup>3</sup> can look a bit strange at first sight for a force, let us remind that the lost energy in a synchrotron is already measured in γ<sup>4</sup>. Next article will be on the perihelion precession of Mercury within neo-Newtonian mechanics.展开更多
Using synchrotron X-ray imaging technique,the segregation evolution in solidifying Al-10 wt% Bi immiscible alloys was investigated at different cooling rates.Irrespective of the cooling rate,most of the Bi solute appe...Using synchrotron X-ray imaging technique,the segregation evolution in solidifying Al-10 wt% Bi immiscible alloys was investigated at different cooling rates.Irrespective of the cooling rate,most of the Bi solute appeared at the upper part of the sample after solidification.The reason for this Bi enrichment phenomenon is different for different cooling rates.Besides Marangoni motion,positive segregation,which has rarely been noticed before,can also make Bi solute transfer to the hot top zone.It is also found that,bubbles（or pores） appear in solidifying Al-10 wt% Bi alloys,and the number of bubbles（or pores） increases with the increase of the cooling rate,while the size of the bubbles（or pores） decreases.展开更多
SPEAR3 is a third-generation synchrotron light source storage ring, about 234 meters in circumference.To meet the beam stability requirement, our goal is to ultimately achieve an orbit variation（relative to the photo...SPEAR3 is a third-generation synchrotron light source storage ring, about 234 meters in circumference.To meet the beam stability requirement, our goal is to ultimately achieve an orbit variation（relative to the photon beam lines） of less than 10% of the beam size, which is about 1 micron in the vertical plane. Hydrostatic leveling system（HLS） measurements show that the height of the SPEAR3 tunnel floor can vary by tens of microns daily without thermal insulation improvements. We present an analysis of the HLS data that shows that adding thermal insulation to the concrete walls of the storage ring tunnel dramatically decreased diurnal tunnel floor motion.展开更多
文摘Newton’s theory of gravitation has been outdated by relativity theory explaining specific phenomena like perihelion precession of Mercury, light deflection and very recently the detection of gravitational waves. But the disappearance of the obvious gravitational force and the variation of time are arguable concepts difficult to directly prove. Present methodology is based on hypotheses as expressed in a previous article: a universal time and an inertial mass variable according to the Lorentz factor (which could not be envisioned at Newton’s age). Because this methodology is mainly stood on Newtonian mechanics, it will be called neo-Newtonian mechanics. This theory is in coherence with the time of the Quantum Mechanics. In Newtonian mechanics, all forces, including gravitational force, are deducted from the linear momentum. Introducing the variable inertial mass, the result of the demonstration is an updated expression of the net force at high velocity: F = γ<sup>3</sup>m<sub>g</sub>a. If such a factor in γ<sup>3</sup> can look a bit strange at first sight for a force, let us remind that the lost energy in a synchrotron is already measured in γ<sup>4</sup>. Next article will be on the perihelion precession of Mercury within neo-Newtonian mechanics.
基金financially supported by the National Natural Science Foundation of China(Nos.51027005,51271119 and51574165)Shanghai Science&Technology Committee(No.11JC1405900)
文摘Using synchrotron X-ray imaging technique,the segregation evolution in solidifying Al-10 wt% Bi immiscible alloys was investigated at different cooling rates.Irrespective of the cooling rate,most of the Bi solute appeared at the upper part of the sample after solidification.The reason for this Bi enrichment phenomenon is different for different cooling rates.Besides Marangoni motion,positive segregation,which has rarely been noticed before,can also make Bi solute transfer to the hot top zone.It is also found that,bubbles（or pores） appear in solidifying Al-10 wt% Bi alloys,and the number of bubbles（or pores） increases with the increase of the cooling rate,while the size of the bubbles（or pores） decreases.
基金Supported by US Department of Energy(DE-AC02-76SF00515)the SULI program at SLAC National Laboratory
文摘SPEAR3 is a third-generation synchrotron light source storage ring, about 234 meters in circumference.To meet the beam stability requirement, our goal is to ultimately achieve an orbit variation（relative to the photon beam lines） of less than 10% of the beam size, which is about 1 micron in the vertical plane. Hydrostatic leveling system（HLS） measurements show that the height of the SPEAR3 tunnel floor can vary by tens of microns daily without thermal insulation improvements. We present an analysis of the HLS data that shows that adding thermal insulation to the concrete walls of the storage ring tunnel dramatically decreased diurnal tunnel floor motion.
