Nacre is one of the general construction units of mollusk shells , thoroughly studying on it can provide insight not only into the pearl - culture , but also into fabrication of advanced organic - inorganic composite materials 珍珠层是软体动物硬壳中普遍发育的一种结构单元，对其进行深入研究可为人工培育珍珠及制造现代有机-无机复合材料提供科学依据。
Compare a 5mm freshwater cultured pearl with a 10mm south sea cultured pearl and the difference in the amount of nacre is obvious . the difference in luster is as clearly visible as the difference in the pearl sizes 所以当光线照射到珍珠上以后，一部分被表面反射，而另一部分则进入珍珠内部，被另一层珍珠层反射，当然，还会有一部分再进入到更深的珍珠层。
Finally , the effects of carotenoids in nacres or pearls on their commercial value , and the formation mechanism of nacres are discussed preliminarily in terms of the previous works and the results done in this paper 最后在总结前人及本文工作资料的基础上，对珍珠及珍珠层中类胡萝卜素的存在对珍珠(层)价值和质量的影响及珍珠层的形成过程两个问题进行了初步探讨。
In pearls , the nacreous layers are generally translucent and composed completely of aragonite , whereas layers without pearly luster are opaque and composed of aragonites and / or vaterites with their relative concentrations different in different pearls 其中具珍珠光泽的珍珠层一般呈半透明状，均?文石组成；无珍珠光泽的不透明层有时由文石组成，有时由六方碳钙石组成。
This suggestion not only provides new scientific evidence for the nacre used as pharmaceutical and hygienical products , but also is of significance to the bleaching of pearl so as to increase the quality and the commercial value of pearls 该研究成果为扩大珍珠及珍珠层在药用及保健品等领域的应用提供了科学依据，并对珍珠的漂白进而提高其商业价值具有重要的现实意义。
Surface microtopography , representation and tracing of nacreous layers of pteria penguin and blister pearl from sanya , hainan province , are studied by using interference microscope and environmental scanning electron microscope and atomic force microscope 摘要采用干涉显微镜、环境扫描电子显微镜、原子力显微镜对海南三亚企鹅贝及其附壳珍珠的珍珠层表面微形貌进行了研究。
The experiments show that nacre , a type of natural nano - bioceramic material , when used as bone implant for reconstruction of bone defects , is not only biocompatible and biodegradable , but also osteoconductive and osteoinductive 本文根据国外文献有关利用珍珠层作为骨植入材料的研究报道，就珍珠层的生物相容性和可降解性，及其所具有的骨诱导和骨传导作用的动物临床实验结果，进行了综合分析和论述。
And also , these two crystal orientations varying with the different positions in the same nacre of shells clearly shows the structurally inhomogeneities of nacre . these results offer new insight into the study of the nacre formation 对同一三角帆蚌贝壳珍珠层，文石晶体的这两种择优取向的程度随壳结构位置的变化而变化，反映了三角帆蚌珍珠层结构的不均匀性，为研究珍珠层的成因提供了新的思路。
3 ) in shell of hyriopsis cumingii ( lea ) , the prismatic layers and the nacreous layers are all composed of aragonite minerals , and aragonite crystallites in prismatic layers show obviously preferential orientation of [ 012 ] axis perpendicular to the shell layers , so it is considered that the orientation of aragonite crystallites in prismatic layers perhaps play an important role in deciding the orientation of aragonite crystallites in nacre and acts as one of template to resulting the formation of aragonite with [ 012 ] orientation perpendicular to nacreous layers in nacre 3 )与海水贝壳明显不同的是，三角帆蚌棱柱层矿物相与珍珠层一样皆为文石相，同时查明棱柱层中文石晶体具[ 012 ]轴垂直壳层面的明显的择优取向。本文认为，三角帆蚌棱柱层中文石晶体的择优取向可能对珍珠层中文石晶体的择优取向存在模板导向的作用，导致珍珠层[ 012 ]定向的文石晶体的形成。
Main conclusions of this work are drawn as follows : 1 ) in nacre of hyriopsis cumingii ( lea ) shell , the aragonite crystallites exist two kinds of orientation , one . which is generally accepted , is the c axis of aragonite perpendicular to nacreous layers , the second , which is proposed in this paper , is the [ 012 ] axis of aragonite perpendicular to nacreous layers 本文所获得的主要成果有： 1 )明确提出三角帆蚌珍珠层中文石晶体的择优取向除了存在公认的其c轴垂直珍珠层面外，还存在其[ 012 ]轴垂直珍珠层面的新取向。
