激光打印的聚合物微棒通过低频电场在阴性液晶中的推进

A rocket's velocity in the presence of a gravitational field is decreased by the amount of force exerted by Earth's gravitational field, which opposes the motion of the rocket. If we consider thrust, that is, the force exerted on a rocket by the exhaust gases, then a rocket's thrust is greater in outer space than in the atmosphere or on a launch pad. In fact, gases are easier to expel in a vacuum.
A rocket's acceleration depends on three major factors, consistent with the...

Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...

Rockets range in size from small fireworks that ordinary people use to the enormous Saturn V that once propelled massive payloads toward the Moon. The propulsion of all rockets, jet engines, deflating balloons, and even squids and octopuses are explained by the same physical principle: Newton's third law of motion. The matter is forcefully ejected from a system, producing an equal and opposite reaction on what remains.
The motion of a rocket in space changes its velocity (and hence its...

Consider two point charges, each exerting Coulomb force on the other. It is possible to describe the Coulomb interaction via an intermediate step by defining a new physical quantity called the electric field.
In the new picture, imagine that the first charge sets up an electric field independent of all other charges in the universe. When another charge comes in its vicinity, the second charge experiences an electric force depending on the electric field at that point. The source charge does not...

Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...

The electric field and electric potential are related to each other. If the electric field at various points in the region of interest is known, it can be used to calculate the electric potential difference between any two points. Similarly, if the electric potential is known for various points, then it is possible to calculate the electric field.
In general, regardless of whether the electric field is uniform, it points in the direction of decreasing potential because the force on a positive...