1 Equivalence Relations 【Definition】A relation R is defined on a set S if for every pair of elements (a, b), a, b S, a R b is either true or false. If a R b is true, then we say that a is related to b

1、验证电阻，感抗、容抗与频率的关系，测定R~f，X ~f与X ~特性曲线。 2、加深理解R、L、C元件端电压与电流间的相位关系

where, R(Qi) is the revenue function and C(Qi) is the cost function of firm i. For profit maximisation the derivative of profit is zero, which amounts to saying that the derivative of revenue is equal to the derivative of cost: MRi

Corresponding author. E-mail address: ring@mail.uni-mainz.de (U. Ring) 1 Institut für Geowissenschaften, Johannes-Gutenberg Universität, Becherweg 21, 55099 Mainz, Germany 2 Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06520, USA January

Consider a digraph G = (V, E) with edge-weight function w : E → R. The weight of path p = v1 → v2 → L → vk is defined to be

1若电荷均匀分布在长为L的细棒上,求证: (1)在棒的延长线,且离棒中心为r处的电

1 . A reaction has the stoichiometric equationA+B=2R. What is the order of reaction? 2. A reaction with stoichiometric equationhas the following rate expressionWhat is the rate expression for this reaction if thestoichiometric equation is written as A+2B=2R+S?A B R S2

通过1：2的比例建立水力学模型并应用正交表L25（56）设计正交实验，对国内某公司的3t钒铁炉进行底吹N2模拟，研究三点底吹条件下不同底吹位置和底吹流量对钒铁液混匀时间的影响.结果表明，最佳的底吹方案为：模型底吹流量为1306 L/h，底吹点位置为e（0.7R）、d（0.6R）、e（0.7R）；底吹流量和底吹位置对混匀时间均有显著性影响，对混匀时间进行拟合可知混匀时间与底吹流量呈幂指数关系，指数值为-0.5211

在相似原理的基础上,对天津钢管公司150t钢包精炼吹氩过程进行了水模拟实验(模型、原型几何比例为1:4).实验发现,原型钢包吹氩位置不尽合理,透气砖顶面面积偏小,吹氩流量偏大.通过对以上三指标的优化,确定合理的吹氩工艺参数为:将吹氩孔位置由原来的距钢包底中心分别为0.555R和0.634R移动到1/3R处,将透气砖顶面直径由原来的16mm扩大到35mm,吹氩流量减少到0.44m3·h-1.水模拟实验为原型钢包的工艺改进提供了依据

1 一半径为a的导体球, 被围在内半径为b、外半径为c，相对介电系数为r 的介质同心球壳内，若导体球带电荷量为Q， 求D(r)，E (r)和导体表面电势