最具有经济价值的铁矿包括磁铁矿和赤铁矿.Iron ores of greatest economic interest contain magnetite and hematite.A-Fe2O3(赤铁矿 ) 是中子衍射最先研究的化合物之一.A - Fe 2 O 3 ( haematite ) was one of the first compounds to be studied by neutron diffraction.发现一种...
A first-class worker, she operated the difficult Jacquard looms.她技艺高超，操作着复杂的提花织布机。These include dobbies, cam motions, electronic Jacquard machines and Jacquard harnesses.产品包括凸轮开口装置、电子多臂机 、 电子提花机和提花织造用的通丝.Covered with per...
Many forest tree species have multiple archegonia which, after fertilization produce a number of proembryos.许多林木树种都有颈卵器, 受精以后便产生许多原胚.A similar section through the female plant reveals several bottle - shape archegonia , ...