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1.
汪家訸 《应用数学和力学(英文版)》1990,(5)
In this paper we use the Jacobian integral of the circular restricted three-body problemto establish a testing function of a moving testing particle when it moves like a planet.Thisfunction determines whether or not the particle will stay in a definite region(which may becalled“stable region”,SR).By means of checking with an electronic computer,we can findthat the SR of quasicircular orbit of retrograde planet motion is much less than the SR ofdirect planet motion.It is the reason why the existence of a retrograde planet is very rare. 相似文献
2.
当汽车以很快的速度驶过一座拱形桥的时候,乘客一定会发生一种特殊的感觉。这样的感觉也同样会发生在乘电梯下降的一瞬时,这是由于失重状态所引起的。我们长期生活在引力強度不变,约为g=980达因/克(或厘米/秒~2)的空间里。由于重力是一种体积力,它与质量成比例地分布在我们人体的各部组织里,因此我们人体的生理机能已习惯于忍受这样強 相似文献
3.
本文用圆型限制三体问题的Jacobi积分来建立一个测检函数,用于确定测试质点作类行星运动时能否长留于一个确定的区域(可称为稳定域).经用电子计算机检定,对于质点作准圆形轨道的情况下,质点作类逆行行星运动的稳定域远小于质点作类顺行行星运动的稳定域.这说明了逆行行星存在的可能性很小. 相似文献
4.
汪家訸 《应用数学和力学(英文版)》1991,12(4):339-343
Now we use the Jacobian integral of circular restricted three-body problem toestablish a testing function of the stability of satellites.This method of criterion may beapplied to the stability problem of satellites when the six elements of the instantaneous orbitof the satellite with respect to its parent planet are known.By means of an electronic computer,we can find the stable region of a satellite with aquasi-circular orbit.The boundary surface of this region is a nearly oblate ellipsoid.Thevolume of this enclosed space is much smaller than that of binding by Hill surface and thatof“sphere of action”.As the expressions of relative kinetic energy of a satellite with respect to its parentplanet have the same form for the direct as well as the retrograde orbits,they can coexist inthe same region at the same time. 相似文献
5.
本文研究有理分式的增广图示,分子分母分别为n及m次多项式的有理分式,它的根轨迹方程的次数,当n+m是偶数时,是y2的(n+m)/2-1次;当n+m是奇数时,是(n+m-1)/2次.因此,n+m≤10的图示数据能用公式计算有理分式的增广图示能应用于研究反馈系统及特征方程的任一实系数作参数的图线特性.用本文理论易证倒分式定理:K1=f(n)(s)/(F)(m)(s),与K2=F(m)(s)/f(n)(s)二者在复数平面上的根轨迹完全相同又由图示知识发现,不论n和m多大,只要有理分式的零点和极点在实轴上相间排列,它就没有复数根轨迹,这样的系统不会发生振荡,本文对这种分式可能存在的稳定区作较全面地分析. 相似文献
6.
汪家訸 《应用数学和力学(英文版)》1981,2(6):719-731
In this paper, an approach is introduced to determine the stable interval of the constant term of a characteristic equation by using the theory of extended graphical representation of polynomials. Because the constant an itself is not taken into account and because this method is to get a stable interval of an, not merely to make a stability test for a set of known coefficients, this method of stability criteria has some advantages over the others. The interval of an can be obtained from the calculation of some algebraical expressions when n10, where n is the degree of the characteristic equation. It is very convenient to calculate for the cases n=5 and n=6. When n11, this interval can be found only by the method of numerical solutions. 相似文献
7.
判别的算式和准则本文提出确定特征方程的常数项 a_n 的稳定区间的判别法.首先按(1)的系数写出 ... 相似文献
8.
汪家訸 《应用数学和力学(英文版)》1990,11(5):421-428
In this paper we use the Jacobian integral of the circular restricted three-body problem to establish a testing function of a moving testing particle when it moves like a planet. This function determines whether or not the particle will stay in a definite region (which may be called stable region, SR). By means of checking with an electronic computer, we can find that the SR of quasicircular orbit of retrograde planet motion is much less than the SR of direct planet motion. It is the reason why the existence of a retrograde planet is very rare. 相似文献
9.
采用SST k-ω湍流模型对比研究了在q=20.5~40 kW.m^-2,G=205.92~262.51 kg·m^-2·s^-1,p=8~10 MPa边界条件下超临界CO2在加热竖直直管和螺旋管内的换热差异。结果表明,在相同工况下,由于离心力引起的二次流的作用使得螺旋管相比于直管对换热有一定的强化作用,并能有效地抑制换热恶化的发生。但在拟临界点区域螺旋管的换热系数反而低于直管,主要原因是在拟临界点附近物性对换热起主导作用,离心力对管外侧的强化作用有限,而由于离心力和浮升力的弱化作用使内侧会出现显著的局部换热恶化(湍动能被抑制),从而使得截面上平均换热系数低于直管。 相似文献
10.
从一般的中学物理书上所附述的电学史中可以看出‘摩擦起电’是人类研究电学的一个起始现象;而就教材的内容来说,‘摩擦起电’对了解电的基本性质的帮助很大;所以不论依科学发展史或理解的逻辑顺序的观点看,摩擦起电在中学物理学里都是不可缺少的一部份教材。就我个人的经验和体会知道:由于摩擦起电现象本性的复杂性,其中存在着相当多的问题,而这类问题的解答有些不是一般教科书或参考书上所能找得到的;在以往国内的一般通俗科学杂志上也没有看到过对这些问题有较充分的讨论。因此我不自揣简陋,收集了一些资料,向自己拟定的一些问题作主观的解答,以供同志们在教学时的参考。不过这些资料产生在不同时期和不同国家,他们的实验技能和仪器的精确程度都很难从他们的论文中准确判 相似文献