2020年国际物理奥林匹克竞赛实验试题介绍及解答

2020年国际物理奥林匹克竞赛实验试题为“晶体学”.试题从一维光栅出发,引导选手寻找衍射花样和晶体结构间的对应关系,最后测定出未知晶体的结构.本文介绍了试题内容和组委会提供的标准答案,并且在个别处提供了其他解法.

山东传统家具的文化起源探讨

通过对山东传统家具的文化起源进行综述,以此探讨山东传统家具的制作技艺与礼制观念,对于系统性构建山东传统家具文化体系具有重要的理论意义。通过整理相关文献后,对山东传统家具中比较有代表性的工艺家具以及流行于山东的鲁班信仰来源、发展进行简要概述,指出山东传统家具与本地区的生活习俗、价值观念以及资源等密切结合,带有鲜明的礼制观念痕迹。得出结论:山东传统家具与齐鲁文化紧密相连,受到社会等级的影响,其表现出超越于家具之上的政治和伦理色彩。家具的陈设布局与风格受到儒家思想的影响,遵循严格的器用制度,形成了具有山东地域特色和文化特征的传统家具。

倾斜摄影测量技术在矿产资源监测中的应用

随着国家绿色发展战略的提出,矿产资源开发利用需要全面监测和管理。文中提出利用无人机倾斜摄影测量技术和方法,通过构建矿山监测区域的DEM、DOM、实景三维模型等倾斜摄影测量产品,分析监测露天矿山企业在该时间段内的开采量、储量、变化区域以及是否越界违法开采等。通过典型应用案例实际验证,结果表明该方法行之有效,能够方便地对矿山进行快速、准确的监测,有效地解决长期以来矿产资源开发利用与管理粗放的问题。

Improvement of Magnetoresistive Character of NiO/NiFeCo/Cu/NiFeCo Exchange-Biased Spin-Valves Through Annealing in Magnetic Field

NiO(70 nm)/NiFeCo(5 nm)/Cu(2 nm)/NiFeCo(5 nm)spin-valve multilayers were prepared by electron beam evaporation.It is found that the magnetoresistive(MR)ratio of the as-deposited films is relatively small(about 1.6%)and there is no apparent biasing in MR curves of as-deposited multilayers due to weak exchange coupling.Through heat treatment at a proper temperature in a magnetic field,the exchange field of the materials increases and the multilayers show good exchange-biased spin-valve MR character with MR value reaching about 2.5%.The proper temperature range for annealing is 200-250℃.With further increasing temperature,MR ratio drops rapidly.

Development of Valence Bands of C_(60)from Submonolayer to Two and Three Dimensionality

For submonolayer amounts of C_(60)condensed on Sn substrate,the peaks derived from top two occupied molecular orbitals were broadened by 0.3eV in comparison with solid C_(60).For coverageθ<1 monolayer,the broadenings are independent of the coverage.It indicates that the delocalizations of electrons in valence bands of C_(60)are weak and the widths do not reflect the true band dispersions.

Plasmon Excitation in 2D and 3D C_(60) Studied by Photoemission

For near monolayer(ML)C_(60) condensed on Sn substrate,x-ray photoemission studies of Cls level reveal a feature centered about 22eV below the main peak.Analyses show that the feature is caused by the plasmon loss of the two dimensional C_(60) film.Bulk plasmon loss peak(~28 eV blow the main peak),which has been observed on thick C_(60) films,was not observed on the C_(60) films with coverageθ<2 ML.It indicates that the 28eV energy loss feature is due to a bulk plasmon associated with the solid C_(60) but not a single C_(60) molecule.

Photoemission Evidence for Dilute K-doped Phase Kx C_(60) with x<0.2

A shift about 0.3eV to higher binding energy is reported in the valence band and Cls core level of Kx C_(60)(x<0.2).Analysis shows that the result could not be interpreted by a mixture of C_(60) and K3 C_(60).A dulite K-doped phase and fermi level pinning near the lowest unoccupied molecular orbital derived band caused by K-doping are proposed.

Adsorption of Oxygen on K_(x)C_(60) Studied by Photoelectron Spectroscopy

Photoemission spectra of vacuum deposited K-incorporated C_(60)-K_(x)C_(60)(x≈6),before and after exposure to oxygen,show that the interaction between oxygen and potassium forms an overlayer of 40 A K-O complex with stoichiometry near to that of potassium peroxide K_(2)O_(2) on the surface.In contrary to the oxidation of potassium film,no potassium oxide K_(2)O has been observed.

冷轧辊用MC5锻钢的碳化物超细化工艺

对轧辊用MC5钢试样采用高温固溶＋高温回火以及高温固溶＋低温奥氏体循环＋高温回火两种不同热处理工艺处理后的显微组织及碳化物进行了观察,研究了高温固溶温度、奥氏体化温度以及奥氏体循环次数对MC5钢组织及碳化物转变的影响,研究结果表明,MC5钢试样采用1050℃×1 h高温固溶＋840℃×0.5 h循环奥氏体化3次＋740℃×6 h高温回火工艺处理后可获得最佳的碳化物细化及组织均匀化效果,碳化物平均尺寸可控制在0-0.5μm之间,且85%的碳化物尺寸在0-0.3μm之间。