万有引力

The great English scientist Newton(1643~1727) published the book Mathematical Principles of Natural Philosophy in 1687. It sums up all his studies and brings forward the three fundamental laws of mechanics, the law of universal gravitation and the laws at celestial mechanics.

英国伟大科学家牛顿(1643~1727)在1687年版的《自然哲学的数学原理》一书总其大成，提出动力学的三个基本定律，万有引力定律，天体力学等。

Based on the fundamental theory of celestial mechanics and the discussion of two body problem under the action of universal gravitation ,the general model which can be continuously used to calculate the apparent place of celestial body in the solar system was derived. Then ,for the specific celestial body ,the material simulating method and the precision verification was given ,and the reason why the error was caused was analyzed and the corresponding method was offered .

摘 要：基于天体力学的基本理论和对万有引力作用下二体问题的讨论，推导出太阳系天体视位置长期计算的一般模型，然后针对特定天体给出了具体的仿真方法和计算结果的精度检验，深入分析了误差的产生原因并提出了相应的改进办法。

This problem, which was certainly known to the ancients, became especially acute in the seventeenth century with the invention of celestial mechanics, which first gave philosophers a certain picture of a way the world might be: it might be a world whose future states were entirely determined by the past and the laws of nature (of which Newton's laws of motion and law of universal gravitation served as paradigms).

这个从很早就被知道的问题，在十七世纪之后变得尖锐起来，因为引力力学第一次给予了哲学家一个明确的世界图景：可能世界的未来事态完全可以被过去和自然律（Newton的运动律和万有引力定律是范例）所决定。

And this one:What is the center of gravity?

再看这条，万有引力的中心是什么？

Bob:And this one:What is the center of gravity?

再看这条，万有引力的中心是什么？

This implies that it is not possible that the centrifugal force is provided by the universal gravity.

这说明该向心力不可能是由万有引力提供的。

That means that the universal gravitation can not supply enough centripetal force.

这说明该向心力不可能是由万有引力提供的。

Chaotic attitude motion of a magnetic rigid spacecraft in a circular orbit of the earth is treated.

研究在地球万有引力场和磁场中的磁性刚体航天器在圆轨道上的混沌姿态运动。

Chaotic attitude motion and its control of a magnetic rigid spacecraft in an arbitrary circular orbit round the earth are investigated.

研究在地球万有引力场和磁场中具有结构内阻尼的磁性刚体航天器在圆轨道上平面天平动的混沌行为及其控制。

With the modernization of scientific and technological progress and industrial development, physics, chemistry, biology, engineering, aerospace, medical, economic and financial areas of the many principles and laws can be described as an appropriate ordinary differential equations, such as Newton's laws of motion, gravity law, law of conservation of mechanical energy, energy conservation law, the law of population development, ecological population competition, disease transmission, genetic variation, the trend of the stock's up V, the floating interest rates, the market equilibrium price changes.

随着科技进步和工业现代化的发展，物理、化学、生物、工程、航空航天、医学、经济和金融领域中的许多原理和规律都可以描述成适当的常微分方程，如牛顿的运动定律、万有引力定律、机械能守恒定律，能量守恒定律、人口发展规律、生态种群竞争、疾病传染、遗传基因变异、股票的涨伏趋势、利率的浮动、市场均衡价格的变化等。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。