推荐一个有机化学基础实验:BINOL的合成及拆分

推荐了一种简便、高效的 1,1′ 联 2 萘酚 (BINOL)的合成与拆分方法作为大学有机化学基础实验     

关于不等式的一点注记

在广义的H－空间中，建立一类不等式，所得的结果推广并统一了文[1],[2]中的某些结果。     

Au/SiO2纳米多层薄膜的制备及其性质表征

利用多靶磁控溅射技术制备了Au/SiO2纳米颗粒分散氧化物多层复合薄膜.研究了在保持Au单层颗粒膜沉积时间一定时薄膜厚度一定、变化SiO2的沉积时间及SiO2的沉积时间一定而改变薄膜厚度时,多层薄膜在薄膜厚度方向的微观结构对吸收光谱的影响.研究结果表明:具有纳米层状结构的Au/SiO2多层薄膜在560nm波长附近有明显的表面等离子共振吸收峰,吸收峰的强度随Au颗粒的浓度增加而增强,在Au颗粒浓度相同的情况下,复合薄膜光学吸收强度随薄膜厚度的增加而增强.但当金属颗粒的浓度增加到一定程度时,金属颗粒相互接触,没有观察到纳米层状结构,薄膜不显示共振吸收峰特征.用修正后的M-G(Maxwell-Garnett)理论对吸收光谱进行了模拟,得到了与实验一致的结果.     

殊途同归的光本性之争

 很久以来,人们对光就进行了各种各样的研究。光的本性到底是什么,这个问题长久以来困扰了很多有智之士。光的波动说笛卡儿（R.Descartes,1596～1650）就光的本性问题,在1637年提出两种假说。一种假说认为,光是类似于微粒的一种物质;另一种假说认为光是一种以“以太”为媒质的压力。虽然笛卡儿更强调媒介对光的影响和作用,但他的这两种假说为17世纪的微粒说和波动说的争论埋下了伏笔。17世纪中期,意大利的格里马第（F.Grimaldi,1618～1663）首先注意到衍射现象,这是光的波动理论的萌芽。     

高考数学的一个新亮点——猜想题

猜想是对所要研究的问题依据已有材料、条件和知识，进行实验、观察、分析、比较、联想、类比、归纳、推理等，作出符合一定的经验与事实的推测性想象的思维方法．牛顿指出：“没有大胆的猜想，就做不出伟大的发现”。猜想是发现问题、解决问题的一种重要的思维方法，是创新思维的重要组成部分，猜想也是数学发展的动力，数学理论的重大突破往往起源于立意深邃的猜想，正是无数数学家们的猜想，数学科学才发展到当今的现代数学。由于猜想可让学生体验数学发现和创造的历程，培养和发展他们的创新思维和合情推理能力，更能体现高考的选拔功能，因此近几年猜想题倍受高考命题老师的亲睐，成为高考数学题的一个新亮点．本文试对这类题型及解法作一综述，供参考．     

Nuclear Shadowing Effect on the K Factor in Au—Au Collisions

We investigate the nuclear shadowing effect on the K factor in the Drell-Yan process by introducing a Shadowing factor into the corresponding quantum chromodynamical αs order corrections.K factors for Au-Au collisions are calculated at the centre-of-mass system energies √s=60,130 and 200 GeV while the nuclear shadowing factor is taken into account.The numerical results indicate that the nuclear shadowing factor obviously raises the K value in the small x region,and for the same nucleon the K valus becomes smaller as the energy increases.The nuclear shadowing effect could be one reason for creating the non-constancy of the K factor.     

Theoretical Research on a Kind of Quantum Left-handed Metamaterial

Recently, research on left-handed materials （LHMs） has attracted considerable attentions. The LHMs are a kind of metameterial which have negative permittivity and negative permeability, which lead to negative refractive index in a frequency range. The LHMs that have been available so far are in the microwave range and are usually composed of classical particles, such as split-ring resonators. Some quantum phenomena such as spontaneous emission of atoms in the LHMs which are considered to be ＇classical background＇ have also been investigated. Many potential applications of LHMs have been proposed, such as superlenses which, in principle, can achieve arbitrary subwavelength resolution.     

A Reliability Analysis of Calculated Results for Odd-Even and Odd-Odd Nuclei in Relativistic Mean-Field Theory

We calculate the binding energies of Ni, Cu, Xe, Cs, Pt, Au, Np, Pu isotope chains using two interaction parameter sets NL-3 and NL-Z, and compared the relative errors of the even-even nuclei with those of odd-even nuclei and odd-odd nuclei. We find that the errors of binding energy of odd-even and odd-odd nuclei are not bigger than the one of even-even nuclei. The result shows that comparing with even-even nuclei, there is no systematic error and approximation in the calculations of the binding energy of odd-even and odd-odd nuclei with relativistic mean-field theory. In addition, the result is explained theoretically.