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1、第十六周周五物理现在学习的是第1页，共39页 The concept of atomic structure in quantum mechanics现在学习的是第2页，共39页n=1,2,3,4,5,K,M,N,O,P,l=0,1,2,3,4,5,(n 1)s,p,d,f,g,h,Therefore,in Element periodic Table K(n=1)L(n=2)M(n=3)N(n=4)s s p s p d s p d f Atomic Shells:现在学习的是第3页，共39页The ground-state configuration(组组态态，位位形形)of atoms.
2、1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6dn2(2l+1)1s2 2s22p6 3s23p64s1Potassium(K 钾钾)Z=19,现在学习的是第4页，共39页Pauli exclusion principle:filling such quantum states:Coordinate rep.Quantum number rep.现在学习的是第5页，共39页Quantum states for Hydrogen or lithium(Li,锂）锂）1S11S22S11S22S1现在学习的是第6页，共39页Another
3、example:write the possible quantum states of 3p11S22S22p63S23p1现在学习的是第7页，共39页X-rays diffractionCompton Effect现在学习的是第8页，共39页X X射线三维成像可射线三维成像可显示心肌活动节律显示心肌活动节律http:/ 现在学习的是第9页，共39页11.1 The fundamental knowledge and the production of x-raysX-rays are produced by electrons Electron accelerated by103 to 1
4、06V electrons with high speed strike a metal target x-rays.observed by Rntgen in 1895 and named as Rntgen rays(伦琴射线伦琴射线).现在学习的是第10页，共39页 X-rays are electromagnetic waves The energy of x-ray photons is E=hv.Wavelengths of x-rays is 0.001 to 10nm.世界最强世界最强X射线激光器：比地球上光源亮射线激光器：比地球上光源亮10亿倍亿倍 http:/ equipm
5、ent of the X-ray productionThe conditions of X-ray production:(1)high speed electrons beam (2)proper target to transform the kinetic energy of electrons into the energy of X-rays.现在学习的是第12页，共39页 The productive set of X-rays:milliammeterStep-up transformerStep-down transformer（filament）X-ray tube现在学习
6、的是第13页，共39页Good heat conductor1%to x-rays99%to heat energyCathodeanode现在学习的是第14页，共39页2.The intensity of x-raysThe intensity of X-rays:The intensity of X-rays is defined as the energies of x-rays passing through the unit area per unit time.Ni is number of hvi现在学习的是第15页，共39页 The intensity of x-rays de
7、pends on:(1)the tube current(more electrons more photons)(2)tube voltage(the energy of each x-ray photon).Under certain tube voltage,the current of filament(灯丝灯丝)control the intensity of x-rays.现在学习的是第16页，共39页3.The hardness of x-rays The hardness of x-ray is defined as its penetrating ability.Penetr
8、ating ability of X-rays depends on the energy of x-ray photons.The energy of x-ray photons depends on the voltage applied to the x-ray tube.Therefore,the hardness of x-rays depends on tube voltage.现在学习的是第17页，共39页11.2 The X-ray spectrumThe plot of X-ray intensity versus wavelength of radiation emitte
9、d by an x-ray tube is called x-ray spectrum.n=1 Kn=2 LKLFrom higher energy levels现在学习的是第18页，共39页 X-rays production is involved in two distinct processes:(1)continuous spectrum:Some of the electrons are stopped and deviated by the target.现在学习的是第19页，共39页(2)Characteristic spectrum:electrons transfer th
10、eir energy in whole or in part to the atoms of the target to excite the atoms.现在学习的是第20页，共39页 Cutoff wavelength现在学习的是第21页，共39页11.3 The basic properties of x-raysThe general properties of x-raysIonizing function X-ray enables the atoms and molecules to be ionized and this characteristic is quite usef
11、ul in medical treatment.现在学习的是第22页，共39页Fluorescence function(荧光作用荧光作用):x-ray Fluoroscopy(透视透视)现在学习的是第23页，共39页 Actinic(光化学的光化学的)function:causing many chemical reaction.Such as x-ray photography biological effect:This function is the basis of radioactive(放射的放射的)treatment in medicine and also the reaso
12、n to protect.penetration capability:Both x-ray Fluoroscopy(透视透视)&x-ray photography(摄摄影影)requires such function.现在学习的是第24页，共39页11.4 The attenuation(衰减衰减)of x-raysWhen x-rays go through matter,various interactions will be happened in the process.X-rays are absorbed by matter.The attenuation law of mon
13、ochromatic x-raysWe use the word“monochromatic”as different matters have different abilities on absorbing different wavelength of x-rays.现在学习的是第25页，共39页Where I0 is the intensity of x-rays and I is the intensity of x-rays after penetrating through the x thickness of matter.is the linear attenuation c
14、oefficient.For a specific matter,the attenuation is proportional to the density of the matter.Because of this,the mass attenuation coefficient,m,could be defined,denoted asUnits of x,cm,cm-1现在学习的是第26页，共39页It can be used to compare the absorbing abilities among different materials.If we introduce the
15、 mass thickness xm=x,the attenuation equation could be written as Units:xm(gcm-2),m(cm2 g-1)现在学习的是第27页，共39页The thickness or the depth which could absorb the half amount of incident x-rays is called half-value depth(or thickness).(半值厚度半值厚度Or半衰减层厚半衰减层厚度度):I=I0/2现在学习的是第28页，共39页11.5 Applications of x-ra
16、ys to medicine1.Treatment The x-rays used in clinic treatment is mainly for cancer.X-rays can induce a series of biological effects in human body(ionizing,Compton effect,producing electron-positron pairs).The function of x-rays can kill cancer cells or at least can reduce their fission speed.现在学习的是第
17、29页，共39页2.DiagnosisFluoroscopy(透视透视)and photography(摄影摄影):Homogeneous intensity of x-rays Non-Homogeneous intensity of x-rays Human bodyDifferent absorptionsnegative film fluorescent screen现在学习的是第30页，共39页 Digital subtraction angiography(数字数字减影血管造影减影血管造影)Taking photosDigital Taking two photosOne norm
18、alOne with contrast mediumDo subtraction现在学习的是第31页，共39页现在学习的是第32页，共39页3.X-CT Computerized Tomography(X射线断层射线断层摄影术摄影术)CT shows：subarachnoid hemorrhage(蛛网膜下腔出血)How to get the image?现在学习的是第33页，共39页Basic principle of CT:(1)As different tissue has different absorbing coefficient and different thickness a
19、lso has different absorbing coefficient ,the coefficient are taken as a parameter.(2)The principle is to set up the distribution of the coefficient in each part of every layer of the material in question and using computer to reconstruct the image of the material.现在学习的是第34页，共39页Reconstruction of ima
20、ge 1 2 3 4 n-1 n.lIn现在学习的是第35页，共39页11122122每次照射可以到每次照射可以到In，可算出，可算出 的和的和891075So we have:3 5 7 2现在学习的是第36页，共39页4.CT ScannerCT Scanner:Computerized Tomography Scanner:an x-ray machine that can produce stereographic images(former name:CAT Scanner(Computer-Aided Tomography)现在学习的是第37页，共39页PET:positron emission computerized tomography 现在学习的是第38页，共39页Classroom Quiz:(1)Write the ground-state configuration(组组态态，位形位形)of Boron(硼硼)with Z=5.(2)Write the possible electronic quantum states that could be possible taken for the outmost sub-shell electron of Boron.现在学习的是第39页，共39页