医学物理学-chapter 9 EM_14_p课件.ppt

Chapter 9 Electricity and Magnetism;7.1 Electrostatic field; Electric field intensity; Electric potential energy (电势能); Electric dipole (偶极子); The electric potential of an electric dipole (偶极子的电势); The dielectrics (电介质); Electric field in dielectrics;The capacitance C is defined as:; bio-membrane and bio-electricity;V2;Take natural logarithm on both sides;As n ? C, we have n1/n2 = C1/C2;When the membrane lets negative ions pass only, the above take “+”; Applications of Nernst equation: (1) Resting potential of cells (静息电位);Example: nerve cell (neuron). There are K+, Na+, Cl- and other ions in the nerve cells. Their concentrations are listed as follows:;Experiment shows that the resting potential for nerve cell is ;Cl-:Uio ≈ Uex; Applications of Nernst equation: (2) Action potential (动作电位) of cells;Resting potential; Cardio-electric knowledge;Cardio muscle cells;Cardio-electric dipole (心电偶) ：At different positions, it forms different potential. ;Electro-cardiogram ;心电图导联(electrocardiogram lead) /view/0f4877eaaeaad1f346933f9a.html;Using the potential formula of a dipole;Electrocardiograph (心电图机);Six kinds of anterior electrocardiographic leads (六种胸前导联);Electrophoresis (电泳);Different particles have different mobility, so they can be divided by electrophoresis. ;Iso_electro_focusing or Immobilized pH gradient;毛细管电泳仪的基本结构 (The basic structures of capillary electro-phoresis) ;根据物质的荷/质比差异来进行分离，比值愈大,跑得愈快。 ;(1) Magnetic induction (磁感应强度) B;(2) Hall effect (霍尔效应);1980年 克劳斯·冯·克利青（德国）发现量子霍尔效应;(b) Fractional quantum Hall effect;(c) Abnormal quantum Hall effect;(3) Mass spectrometer (质谱仪);/p-214146867.html 运动电荷在磁场中的受力; The End? To be continued!