大学教育要适应知识更新

新时期知识的更新非常快,现在的大学生学到的知识,4年下来有一半是旧的,所以高校要使学生知识而更宽。传播知识在新世纪到来时会变得不太重要,重要的是让学生学会如何做人,如何思考问题。因此,高等教育的关键是培养学生的创造力。中国人很聪明,关键是怎样开发出来。教师的职责第一是教学生怎样做人;第二是教他们怎样思考同历;第三才是传授知识。知识更新特别快的另一个后果是要“终生受教育”,活到老学石老。大学教育要适应知识更新@杨福家$复旦大学     

高能离子弹性散射测定高温超导薄膜的元素配比

本文介绍了用8.8MeV氦离子弹性散射测定Y-Ba-Cu-O超导薄膜元素配比的一种新方法。由于在8.8MeV时~(16)O(α,α)~(16)O非卢瑟福共振散射截面比卢瑟福弹性散射截面大25倍,因而一次测量即能得到Y-Ba-Cu-O全部元素的配比。本方法也适用于Bi-Sr-Ca-Cu-O和Tl-Ba-Ca-Cu-O等其它超导体系元素配比的测定。     

福泉山良渚文化玉器的PIXE分析

报道用质子激发X荧光技术（PIXE）分析福泉山良渚文化玉器的实验结果。采用PIXE方法可以可靠地鉴别福泉山玉器的种类,福泉山玉器中有软玉、也有岫玉。它们与江苏溧阳小梅岭玉在元素含量上差别很大,但软玉与新疆和田出产的软玉很类似。分析福泉山软玉铁镁占位比S,可排除杂质元素干扰,得到矿物结构和沁色信息。     

THE STUDIES OF SURFACE LAYER ATOMIC STRUCTURE OF AL(100) BY MEV ION SCATTERING

A UHV system specially designed for studying surface and interface atomic structure by MeV ion scattering and channeling is described. The vacuum in the UHV chamber is 133.332×10-10Pa. The chamber is equipped with an ion gun used for sample cleaning, a translatable four-grid LEED-Auger system used for characterization of the crystal surface, and a three dimensional goniometer. The crystal preparation and cleaning procedure of Al(100) are presented. The surface peak intensity of Al(100)-<100> and Al(100)- <100> has been measured by MeV ion channeling and scattering. The measured surface peak intensity was compared with that of Monte-Carlo simulation. The experimental results indicate that the thermal vibration amplitude of Al(100) surface atoms is 1.2 -1.3 times that of bulk atoms. The relaxation of first layer for Al(100) is less than -0.005nm.     

PROGRESS IN ION BEAM ANALYSIS AT FUDAN UNIVERSITY

Progres in ion beam analysis at Fudan University in the recent years is briefly reviewed. Presented as examples of the research activities performed in this field are the following projects: (1) Nuclear potential resonance scattering of 6.25 MeV and 4.25 MeV helium ions for simultaneous compositional analysis of carbon and oxygen in a Mylar, a SnInO, and some other film samples: (2) Determination of stoichiometry of a high-temperature superconducting Y-Ba-Cu-O sample by backscattering of 8.8 MeV helium ions; (3) Backscattering and channeling analysis of multilayered structures periodically consisting of layers of pure Si and alternate layers of Ge and Si, grown on (100) Si substrates by molecular beam epitaxy: (4) Studies of surface structure of Al(100) by the use of MeV ions backscattering and channeling surface peak: and (5) MeV ion microbeam analysis and the use of PIXE method in DNA study. etc.     

COMPOSITIONAL ANALYSIS OF HIGH-TEMPERATURE SUPERCONDUCTOR THIN FILMS BY HIGH ENERGY ELASTIC BACKSCATTERING OF HELIUM IONS

High energy ion backscattering can be used to enhance the sensitivity of oxygen analysis. At He++ ion energy of 8.8 MeV, the yield due to oxygen is about 25 times larger than that predicted by Rutherford formula. The elemental stoichiometry of some bulk and thin film superconductor samples was determined. The details of the measuring method are discribed.     

用PIXE研究经络穴位元素浓度的异常分布

采用外束质子激发Ｘ荧光发射技术测定了与穴位位置相对应的结缔组织结构中元素浓度的特异性分析,初步发现,穴位区富集有Ｃａ,Ｐ,Ｋ,Ｆｅ,Ｚｎ等元素。     

用质子激发X荧光分析技术鉴别玉器种类

质子激发Ｘ荧光分析中以测定玉器的主量、次量及微量元素的成分和含量,因而可以将那些外形及颜色相近的玉器因其化学组分的不同而清楚地分开,并得知其真实的材料种类。对于主要化学组分一致的同类玉器,如果产于不同的地方,则由于其成矿地区地球化学环境的不同,它们的微量元素种类及含量也将有所不同,因而这一方法也可用来判定玉器的产地。