在教改实践中改进和完善新编教材

同济大学应用数学系编写的面向 2 1世纪课程教材《微积分》由高教出版社正式出版已三年多了 .在此期间 ,我校围绕新教材的使用 ,广泛听取了校内外教师和专家的意见和建议 ,对教材中存在的问题和不足之处进行修正 ,到今年初 ,完成了该书第二版的编写 ,新版已在七月份正式出版面世 .在这次修订中 ,除了对原书中存在的不当与错误之处作订正外 ,主要围绕提高教材的可教学性这个中心 ,就一些问题进行了再思考 ,并根据教改实践的经验及同行们的意见得出了自己的认识和结论 ,对教材作了修订 .前几年 ,国家出版了一大批改革教材 ,经过一段时期的使用…     

Field Emission from Silicon Nanocrystallite Films with Compact Alignment and Uniform Orientation

Patterned silicon nanocrystallite (SINC) films were fabricated on (100) orientation p-type boron-doped sificon wafer by the hydrogen ion implantation technique and the anodic etching method. The efficient field emission with low turn-on field of about 3.5V/μm at current density of 0.1μA/cm^2 was obtained. The emission current density from the SiNC films reached 1mA/cm^2 under a bias field of about 9.1V/μm. The experimental results demonstrate that there are great potential applications of the SiNC films for fiat panel displays. A surface treatment with hydrogen plasma was performed on the SiNC films and a significant improvement of emission properties was achieved.     

Evolution of Shower Parton Distributions in a Jet from Quark Recombination Model

The evolution of shower parton distributions in a jet is investigated in the framework of a quark recombination model. The distributions are parameterized and the Q^2 dependence of the parameters is given by polynomials of In Q^2 for a wide range of Q^2     

YGG:Cr~(3+)晶体的光谱特性

本文通过实验研究了YGG:Cr~(3+)晶体的光谱特性,报道了室温下的吸收谱,10,133,300K的荧光谱,以及荧光寿命、无辐射跃迁几率、辐射量子效率与温度之间的依赖关系。从吸收谱及荧光谱中确定在C_(3i)(S_6)低对称场微扰下,Cr~(3+)离子在基质YGG中~2T_1能级分裂的子能级及基态~+A_2~2E零声子跃迁R线的位置。     

全球大气重力波联测期间电离层扰动的台阵观测

本文利用武汉电离层观象台的加密频高图和三站Doppler图记录及新近提出的短波扰动反演方法,分析了1985年全球大气重力波联测(WAGS)期间10月18日这天白天的重力波扰动,发现在该日扰动中有两列不同形态的波列分别属于中尺度的内重力波和大尺度的导制重力波。本文还进一步估算了这两列重力波的水平传播参量,深入分析了它们的频谱结构的高度变化特征,发现了重力波功率谱谱峰的分裂和偏移等重要现象。本文结果表明,新的反演方法使电离层无线电汉诊断的简易短波实验系统,也能成为探测和研究重力波一类大尺度电离层动力过程的有效手段。     

碳分子线基态特性理论研究

从第一原理出发,利用密度泛函理论B3LYP系统研究了碳分子线Cn(n＝3～10)的电子结构特性.对优化结果分析发现,由于离域效应的作用,当n为奇数时,分子线基态为单重态,反之,当n为偶数时,三重态为其稳定的基态.对其电子结构分析可得,随着n的增加,体系能量逐渐降低;同时本文确定了分子线体系最高占据轨道HOMO能量EH、最低未占据轨道LUMO能量EL与n的关系式,即EHn-2＜EHn＜EHn+2,ELn-2＞ELn＞ELn+2.因而碳分子线的费米能级会表现出特有的奇偶性.该工作将有利于准确认识分子器件的伏安特性,设计出良好性能的分子器件.     

Optimal conclusive teleportation of a d-dimensional two-particle unknown quantum state

A conclusive teleportation protocol of a d-dimensional two-particle unknown quantum state using three d- dimensional particles in an arbitrary pure state is proposed. A sender teleports the unknown state conclusively to a receiver by using the positive operator valued measure（POVM） and introducing an ancillary qudit to perform the generalized Bell basis measurement, We calculate the optimal teleportation fidelity. We also discuss and analyse the reason why the information on the teleported state is lost in the course of the protocol,     

高级球差、正弦差公式在光学自动设计中的应用

将高级象差公式用于光学自动设计,编制了一个具有自动选取变量,平衡象差质量高、速度快的自动设计程序。此程序特别适用于设计大孔径、小视场的光学系统。     

Fabrication of Intrinsic Josephson Junctions on BI2Sr2CaCu2O8＋δ Single Crystals with Reproducible Surface Junctions

Intrinsic Josephson junctions on Bi2Sr2CaCu2O8 δ single crystals are successfully fabricated using photolithography and Ar jon milling .Here we discuss the properties of the surface CuO2/metal bilayers and surface junctions prepared with different crystal cleavage conditions and metal film deposition techniques.We show that,by cleaving the crystal at liquid nitrogen temperature in vacuum,the contents of the (interstitial) oxygen in the Bi-O layers become stable upon cleavage,leading to a CuO2/metal bilayer and to surface junctions with reproducible properites,These results can be useful for practical device fabrications as well as for the studies of the contact properties between high Tc superconductors and normal metals.     

大学数学实验课的实践与探索

“数学实验课”是我国高等学校中新开设的一门课程，目前仍处于探索和试点阶段。从国内出版的数学实验课教材来看，对这门课的认识还存在很多分歧。本介绍了我们在数学教学改革中开设数学实验课的一些认识与体会，强调了数学实验课。的重要性，提出了数学实验课与数学基础课，数学建模课构成了二十一世纪大学数学新的课程体系的观点，阐述了数学实验课的特点是必须突出实验特色。并简要地结合一堂数学实验课的教学经验强化了我们对数学实验课的认识。最后，指出了数学实验课中有大量问题值得研究。