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1、第十六周周五物理第1页，此课件共39页哦 The concept of atomic structure in quantum mechanics第2页，此课件共39页哦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:第3页，此课件共39页哦The ground-state configuration(组组态态，位位形形)of atoms.1s,2s,
2、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,第4页，此课件共39页哦Pauli exclusion principle:filling such quantum states:Coordinate rep.Quantum number rep.第5页，此课件共39页哦Quantum states for Hydrogen or lithium(Li,锂）锂）1S11S22S11S22S1第6页，此课件共39页哦Another example:writ
3、e the possible quantum states of 3p11S22S22p63S23p1第7页，此课件共39页哦X-rays diffractionCompton Effect第8页，此课件共39页哦X X射线三维成像可显射线三维成像可显示心肌活动节律示心肌活动节律http:/ 第9页，此课件共39页哦11.1 The fundamental knowledge and the production of x-raysX-rays are produced by electrons Electron accelerated by103 to 106V electrons with
4、 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).第10页，此课件共39页哦 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:/ equipment of the X-ray pro
5、ductionThe 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.第12页，此课件共39页哦 The productive set of X-rays:milliammeterStep-up transformerStep-down transformer（filament）X-ray tube第13页，此课件共39页哦Good heat con
6、ductor1%to x-rays99%to heat energyCathodeanode第14页，此课件共39页哦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第15页，此课件共39页哦 The intensity of x-rays depends on:(1)the tube current
7、(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.第16页，此课件共39页哦3.The hardness of x-rays The hardness of x-ray is defined as its penetrating ability.Penetrating ability of X-rays depend
8、s 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.第17页，此课件共39页哦11.2 The X-ray spectrumThe plot of X-ray intensity versus wavelength of radiation emitted by an x-ray tube is called x-r
9、ay spectrum.n=1 Kn=2 LKLFrom higher energy levels第18页，此课件共39页哦 X-rays production is involved in two distinct processes:(1)continuous spectrum:Some of the electrons are stopped and deviated by the target.第19页，此课件共39页哦(2)Characteristic spectrum:electrons transfer their energy in whole or in part to th
10、e atoms of the target to excite the atoms.第20页，此课件共39页哦 Cutoff wavelength第21页，此课件共39页哦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 useful in medical treatment.第22页，此课件共39页哦Flu
11、orescence function(荧光作用荧光作用):x-ray Fluoroscopy(透视透视)第23页，此课件共39页哦 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 reason to protect.penetration capability:Both x-r
12、ay Fluoroscopy(透视透视)&x-ray photography(摄摄影影)requires such function.第24页，此课件共39页哦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 monochromatic x-raysWe use the word“monochromatic
13、”as different matters have different abilities on absorbing different wavelength of x-rays.第25页，此课件共39页哦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 coefficient.For a specific matter,the attenuation
14、 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第26页，此课件共39页哦It can be used to compare the absorbing abilities among different materials.If we introduce the mass thickness xm=x,the attenuation equation coul
15、d be written as Units:xm(gcm-2),m(cm2 g-1)第27页，此课件共39页哦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第28页，此课件共39页哦11.5 Applications of x-rays to medicine1.Treatment The x-rays used in clinic tr
16、eatment 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.第29页，此课件共39页哦2.DiagnosisFluoroscopy(透视透视)and photography(摄影摄影
17、):Homogeneous intensity of x-rays Non-Homogeneous intensity of x-rays Human bodyDifferent absorptionsnegative film fluorescent screen第30页，此课件共39页哦 Digital subtraction angiography(数字数字减影血管造影减影血管造影)Taking photosDigital Taking two photosOne normalOne with contrast mediumDo subtraction第31页，此课件共39页哦第32页，
18、此课件共39页哦3.X-CT Computerized Tomography(X射线断层摄射线断层摄影术影术)CT shows：subarachnoid hemorrhage(蛛网膜下腔出血)How to get the image?第33页，此课件共39页哦Basic principle of CT:(1)As different tissue has different absorbing coefficient and different thickness also has different absorbing coefficient ,the coefficient are tak
19、en 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.第34页，此课件共39页哦Reconstruction of image 1 2 3 4 n-1 n.lIn第35页，此课件共39页哦11122122每次照射可以到每次照射可以到In，可算出，可算出
20、的和的和891075So we have:3 5 7 2第36页，此课件共39页哦4.CT ScannerCT Scanner:Computerized Tomography Scanner:an x-ray machine that can produce stereographic images(former name:CAT Scanner(Computer-Aided Tomography)第37页，此课件共39页哦PET:positron emission computerized tomography 第38页，此课件共39页哦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.第39页，此课件共39页哦