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Inclusions in large diamond single crystals at different temperatures of synthesis 被引量:5
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作者 Fei Han Shang-Sheng Li +8 位作者 xue-fei jia Wei-Qin Chen Tai-Chao Su Mei-Hua Hu Kun-Peng Yu jian-Kang Wang Yu-Min Wu Hong-An Ma Xiao-Peng jia 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第2期439-444,共6页
The inclusions in large diamond single crystals have effects on its ultimate performance, which restricts its industrial applications to a great extent. Therefore, it is necessary to study the inclusions systematicall... The inclusions in large diamond single crystals have effects on its ultimate performance, which restricts its industrial applications to a great extent. Therefore, it is necessary to study the inclusions systematically. In this paper, large diamond single crystals with different content values of inclusions are synthesized along the(100) surface by the temperature gradient method(TGM) under 5.6 GPa at different temperatures. With the synthetic temperature changing from 1200?C to 1270?C,the shapes of diamonds change from plate to low tower, to high tower, even to steeple. From the microscopic photographs of the diamond samples, it can be observed that with the shapes of the samples changing at different temperatures, the content values of inclusions in diamonds become zero, a little, much and most, correspondingly. Consequently, with the temperature growing from low to high, the content values of inclusions in crystals increase. The origin of inclusions is explained by the difference in growth rate between diamond crystal and its surface. The content values of inclusions in diamond samples are quantitatively calculated by testing the densities of diamond samples. And the composition and inclusion content are analyzed by energy dispersive spectroscopy(EDS) and x-ray diffraction(XRD). From contrasting scanning electron microscopy(SEM) photographs, it can be found that the more the inclusions in diamond, the more imperfect the diamond surface is. 展开更多
关键词 INCLUSIONS LARGE DIAMOND single CRYSTALS HIGH PRESSURE and HIGH temperature
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线性低密度聚乙烯流延膜取向与阻隔性能关系研究 被引量:1
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作者 苏萃 任敏巧 +5 位作者 郑萃 姚雪容 贾雪飞 侯莉萍 张韬毅 唐毓婧 《高分子学报》 SCIE CAS CSCD 北大核心 2021年第7期785-796,I0005,共13页
采用广角X射线衍射(WAXD),小角X射线散射(SAXS)和小角激光光散射(SALS)系统地表征了线性低密度聚乙烯(LLDPE)流延膜以及加入成核剂HPN-20E的LLDPE流延膜的多层级凝聚态结构,并研究晶体取向分布与流延膜阻隔性能之间的关系.未加成核剂的... 采用广角X射线衍射(WAXD),小角X射线散射(SAXS)和小角激光光散射(SALS)系统地表征了线性低密度聚乙烯(LLDPE)流延膜以及加入成核剂HPN-20E的LLDPE流延膜的多层级凝聚态结构,并研究晶体取向分布与流延膜阻隔性能之间的关系.未加成核剂的流延膜内PE晶体的主要取向为b轴在TDND(流延膜横向-垂直于流延膜方向)平面内的,以b轴为螺旋轴的螺旋状取向,而以b轴沿MD(流延膜机械方向)方向的方式取向的晶体分布较少.成核剂的加入改变了流延膜内晶体的取向分布以及聚集情况,b轴沿ND方向的螺旋状取向(O_(ND))的晶体明显减少,片晶的尺寸、取向程度以及微观尺寸的晶体聚集情况均发生明显变化.发现在结晶度相近的情况下,晶体的取向排列是影响阻隔性能的关键因素,进而提出用一种半定量的取向结构参数R_(ND),即X射线沿着ND方向得到的晶体(110)与(200)晶面的衍射峰面积的比值,表征晶体取向与阻隔性能之间的关系. 展开更多
关键词 聚乙烯 阻隔 结晶 取向
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