Application of colour metallography in the examination of ancient metals

The use of colour in the metallographic examination of ancient metals is useful both for research and teaching purposes. Application of different optical methods of examination include: polarized light, with or without a first-order red compensator, and differential interference contrast microscopy (DIC). The use of DIC can be combined with the other techniques mentioned in the text for the examination of etched or unetched metal surfaces, which are best observed microscopically using a metallograph. Colour techniques are now used routinely in industrial metallography, and are available for a variety of metals and alloys. Colour tint etching can be used to enhance grain structure or different phases present in the metallic artefact which may not be visible in conventional etched samples, or which lack optical contrast. Many more applications of these techniques in the examination of ancient metals will be published in the literature as they become better known and second-hand equipment with DIC lenses enter the market at a price suitable for conservation laboratories to purchase them.     

薄膜的增透、增反作用与其厚度、折射率之间的关系

以单层薄膜为例 ,首先应用多光束干涉原理 ,推导出光强反射率公式 ,然后讨论薄膜的增透、增反作用与其厚度、折射率之间的关系。     

《墙盘》铭文补释--兼论周代彝铭的文王武王形象

《史墙盘》是迄今所见述西周诸王最为系统的彝器铭文,它代表了周王朝的正统理念,铭文造句谨严,用辞考究。铭文用大段文字叙述周文王、武王的功勋业迹,是为迄今发现的彝铭所仅见者。结合其它资料,可以看出彝铭中的文王形象主题是膺受天命和最为显赫周人先祖,武王形象的主题则是威武刚强。这些对于研究周代史学与文学皆有重要价值。     

薄透镜焦距测量的教学设计

用测量薄透镜焦距实验,开展探究性实验教学,引导设计实验,指导观察、分析、解释实验现象,激励改进实验,在探究中培养学生问题意识和科学思维方法。     

分子力与分子间距离关系的模拟演示

本介绍了用表面张力与水膜高度来模拟演示分子力与分子间距离关系的方法，阐述了演示原理，描述了演示过程，并给出简单演示装置图．     

以错位竞争理念构想地市级电视媒介产业发展战略

错位竞争以取得市场利基(Niche)为目标。媒介产业的错位竞争，就是某一级的某一类媒介产业以取得自身可能占有的媒介资源为市场目标而采取的避免与竞争对手正面交锋的市场策略或理念。以错位竞争理念构想地市级电视媒介产业的发展战略，需要实现三个战略目标：选择合适的媒介生态位作为地市级电视媒介产业的生存与发展空间；定位“受众圈”作为地市级电视媒介产业的目标市场；开创著名的地方性电视媒介品牌。     

Free vibration of piezoelectric annular plate

INTRODUCTIONDuetotheirwideapplicationsinengineer ing ,piezoelectriccrystalplatesattractedmuchattentionandhadbeenextensivelystudiedasre ported .However,mostworkswerebasedonva rioustwo dimensionalapproximations (Dokmeci,1 980 ;Lawson ,1 942 ;Mindlin ,1 952 …     

固支Mindlin 板弯曲问题的辛本征解

Hamiltonian system for the problem on clamped Mindlin plate bending was established by introducing the dual variables for the generalized displacements in this letter. By separation of variables, the transverse eigen-problem was derived based on the sympletic geometry method. With the solved sympletic eigen-values, the generalized sympletic eigen-solution was derived through eigenfunction expansion. An example of plate with all edges clamped was given. The sympletic solution system was worked out directly from the Hamiltonian system. It breaks the limitation of traditional analytic methods which need to select basis functions in advance. The results indicate that the sympletic solution method could find its more extensive applications.     

浅议风险投资的多元退出机制

风险投资的退出机制对风险投资的最终成败有着举足轻重的作用,风险投资的退出机制在整个风险投资体系中处于核心地位。而影响中国风险投资业发展的关键性问题之一就是退出机制不健全。在借鉴国外的成功的经验时,必须结合我国现实情况的约束作全面分析。目前我国的资本市场、产权交易市场、风险投资体系、法律制度都不完善,而机制的完善不可能一蹴而就。因此,现阶段选择切实可行的退出方式以争取发展的时间,同时不断创造条件扫清障碍,最终建立完善的风险投资退出机制是非常必要的。