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。     

泡利的错误

几年前,在翻译美国物理学家温伯格(StevenWeinberg)的《爱因斯坦的错误》和撰写《玻尔的错误》(发表于本刊2013年第5期)时,我就萌生过一个念头,那就是继《爱因斯坦的错误》和《玻尔的错误》之后,若还有哪位现代物理学家的错误值得一写的话,就得说是泡利了。这也正是本文的主题——泡利的错误——之缘起。     

也议"三原色"

牛顿早在1672年就发现了光的色散现象,直到1801年英国医生托马斯·杨才提出了三原色理论,后来赫尔曼·冯·亥姆霍兹将它完善了.三原色是哪三原色?一次我问高职二年级学生.有人说三原色是红、黄、蓝;也有人说是红、绿、蓝;为什么会出现两种不同的"三原色"呢?究竟哪一个才是对的?     

贸易保护死而不僵

显而易见，托马斯·弗里德曼（Thomas L．Friedman）眼中的“世界是平的”已经在全世界深入人心，但是贸易保护主义却动摇了“世界是平的”的根基。1月31日，美国总统奥巴马在国情咨文中宣布成立新的贸易执法部门，这一“意在沛公”的政治诉求可能颠覆“世界是平的”的思维。     

Classical interpretations of relativistic precessions

Relativists have exposed various precessions and developed ingenious experiments to verify those phenomena with extreme precisions. The Gravity Probe B mission was designed to study the precessions of the gyroscopes rotating round the Earth in a nearly circular near-Earth polar orbit to demonstrate the geodetic effect and the Lense-Thirring effect as predicted by the general relativity theory. In this paper, we show in a very simple and novel analysis that the precession of the perihelion of Mercury, the Thomas precession, and the precession data （on the de Sitter and Lense-Thirring precessions） collected from the Gravity Probe B mission could easily be explained from classical physics, too.     

ON RESIDUAL-BASED A POSTERIORI ERROR ESTIMATORS FOR LOWEST-ORDER RAVIART-THOMAS ELEMENT APPROXIMATION TO CONVECTION-DIFFUSION-REACTION EQUATIONS

A new technique of residual-type a posteriori error analysis is developed for the lowest- order Raviart-Thomas mixed finite element discretizations of convection-diffusion-reaction equations in two- or three-dimension. Both centered mixed scheme and upwind-weighted mixed scheme are considered. The a posteriori error estimators, derived for the stress variable error plus scalar displacement error in L_2-norm, can be directly computed with the solutions of the mixed schemes without any additional cost, and are proven to be reliable. Local efficiency dependent on local variations in coefficients is obtained without any saturation assumption, and holds from the cases where convection or reaction is not present to convection- or reaction-dominated problems. The main tools of the analysis are the postprocessed approximation of scalar displacement, abstract error estimates, and the property of modified Oswald interpolation. Numerical experiments are carried out to support our theoretical results and to show the competitive behavior of the proposed posteriori error estimates.     

托马斯-杨之力学贡献

托马斯--杨是一位多才多艺的学者, 在光学、声学、流体动力学、医学、材料力学、 考古学、语言学、保险学等众多领域做出了突出贡献, 但由于种种原因使他在力学方面的贡 献未曾得到学术界的足够重视. 杨在力学方面的研究涉及到材料力学、血液流动力学、能量、 冲击动力学、表面浸润力学、工程结构分析等方面. 他是一位纯粹的自然哲学家, 同时他能 够将理论与实验和工程实际相结合, 实现了后辈力学家所提倡的``技术科学'的理念.     

相对论中的维格纳转动

相对论中的托马斯旋进，国内献论述较少。托马斯旋进实际上是由维格纳转动引起，本对维格纳转动进行讨论，并由此得出托马斯旋进。     

The dissociative ionization and Coulomb explosion of ethane by a femtosecond laser field

Femtosecond laser-induced dissociation and Coulomb explosion of polyatomic molecule C_2H_6 were systematically investigated using a time-of-flight mass spectrometer and a chirped pulse amplifier laser. With the laser intensity varying from 2.4×10^{15}W/cm^{2} to 1.2×10^{16}W/cm^2, strong molecular ions C_2H_n^+ (n=0－6) and atomic ions C^{m+} (m=1－3) signals were observed. The double-peak structure of atomic ions indicated the occurrence of Coulomb explosion. Compared with the nearly isotropic distribution of C^{+}, highly charged ions C^{m+} (m=2－3) exhibited a sharply anisotropic angular distribution, which was attributed to the geometric alignment.