单词	polytype
释义	polytype /ˈpɒlɪtʌɪp / noun Crystallography Any of a number of forms of a crystalline substance which differ only in one of the dimensions of the unit cell.There are four polytypes known.... Microcrystals of the following polytypes were identified: 4H, 6H, 15R, and 18R. Several polytypes of wurtzite were reported at the Negley and Alikanna sites. Derivatives polytypic /pɒlɪˈtɪpɪk/ adjective ... This procedure helped in making an unambiguous distinction of the dielectric behaviour of the polytypic crystal from that of the corresponding 4H structure. The most basic branched polytypic crystal that can therefore be produced using these materials is a tetrapod. polytypism noun ... Neither the concept of polytypism nor the X-ray diffraction technique was known in Domeyko's time. Polytypism is a type of polymorphism wherein different polymorphs exist in different domains of the same crystal. The polytypism in graphite manifests itself in two ways.
随便看	(up) to the hilt up to the mark up to the minute up to the (or one's) eyeballs up to the (or one's) eyes (in) uptown uptowner uptrend upturn UPU uPVC upvote upward upwardly upwardly mobile upwardly (or downwardly) mobile upward mobility upwards upwards (or upward) of upwarp upweight upwelling upwind up with —— up your arse!

英语词典包含243303条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。