一、为什么在负载端还要绝缘? TN—S系统中,要求N线和PE线在电源端相连, 负载端分开,有不少施工人员对此不理解,既然 在电源端N线和PE线是联成一体的,为什么在负 载端还要绝缘?

Chapter 33 Early Quantum Theory and Models of the Atom 1. Planck's Quantum Hypothesis 2. The Photoelectric Effect 3. Compton Effect 4. Wave Nature of Matter

7-1恒定电流 一、电流电流密度 电流:通过截面S的电荷随时间的

作业1A质点运动的描述 1A-1.已知质点的运动学方程F=x(t)i+y(t)j=t2i+(2t+6)j(单位:m)求: (1)质点运动轨迹方程; (2)t=1s时,质点的速度和加速度(指明大小、方向)

Oxide Oxide Metallization Contact processing techniques that are similar to those of today's VLSI circuits, although the device geometry, voltage and current ntSource

Chapter 30 The Wave Nature of Light, Interference 1 Huygens'principle 2 Refraction 3 Young's Double-slit Experimentinterference 4 Intensity in the Double-slit Interference Pattern 5 Interference in Thin Films 6 Michelson Interferometer

Chapter 26 Sources of Magnetic Field 1. Biot-savart's law 2. Magnetic Flux and Gauss'Law 3 Amperes Law 4. Magnetic Materials

Chapter 34Quantum Mechanics 1. Heisenberg Uncertainty Principle 2. Schrodinger's Equation

Chapter 19 Electric Charge and Electric Field 1. Static Electricity; Electric Charge and Its Conservation; Insulators and Conductors; Induced Charge 2. Coulomb's Law 3. The Electric Field and its Calculations 4. Electric Field and Conductors 5. Electric Dipoles

如果曲面由方程z=z(x,y)给出,则有 Dxy 简要证明: 已知(△S)=(△),其中当cosy>0(C取上侧)时取正号, 当cosy0(取下侧)时取负号 又当(,np)是上的一点时,有5=(5,n)因此有