上海市地矿局氮化硅制品厂氮化硅样品结构浅析     

张洁  张乃枝 《上海国土资源》1997,(2):54-57

采用Ｘ射线衍射法测定了上海市地矿局氮化硅制品厂的样品物相组成及结构，并利用扫描电子显微镜分析了样品的显微结构，对其进行了分析。  相似文献   

新型氮化硅钢背缸套          下载免费PDF全文

王三牛 《探矿工程》1992,(5):21-23

新型氮化硅钢背缸套是根据氮化硅材料的特性，将其制作成泥浆泵缸套衬里，用优质碳素钢制作缸套钢背，用温差法进行装配而成。经过试验其使用寿命比普通缸套提高3倍。  相似文献   

Presolar Grains and Their Isotopic Anomalies in Meteorites     

林杨挺  王世杰 《中国地球化学学报》2001,20(1):1-11

Study on presolar grains including diamond,silicon carbide,graphite,silicon nitrite(Si3N4),coundum and spinel isolated from meteorites is summarized in this paper.Except for nanometer-sized diamond,the other grains are micrometers to submicrometers in size.The presolar grains survived mainly in the fine-grained matrix of primitive chondrites and were isolated by chemical treatments.Diamond contains Xe isotopes(Xe-HL),typically produced in p-and r-processes,probably formed in supernovae.Mainstream silicon carbides are enriched in ^29,30Si and ^13C,but depleted in ^15N.They also contain various s-process products,consistent with calculations of AGB stars.Other silicon carbides exhibit much larger isotopic anomalies and are classified as groups X,Y,Z and AB.Among them,group X of SiC is characterized by enrichment of ^28Si and daughter isotopes of various short-lived nuclides,suggesting an origin from supernovae.Graphite can be divided into four density fractions with distince isotopic compositions.They may form in AGB stars,novae and supernovae,respctively,Si3N4 is similar to X-SiC in isotopic composition.Corundum is classified as four groups based on theid oxygen isotopic compositions.AGB and red giang stare are possible sources for the oxide.More comprehensive study of presolar grains,especially discovery of the other types of oxides and silicates,isotopic analyses of individual submicrometer-sized grains and distribution of presolar grains among various chemical groups and petropaphic types of chondrites will provide new information on nucleosynthesis,stellar evolution and formation of the solar nebula.  相似文献   

基于等离子体增强化学气相沉积技术的光电子器件多层抗反膜的设计和制作     

袁贺  孙长征  徐建明  武庆  熊兵  罗毅 《海洋学报》2010,32(10):7239-7244

针对光电子器件端面抗反镀膜的要求,研究了基于等离子体增强化学气相沉积(PECVD)技术的多层抗反膜的设计和制作.首先,对影响SiN_x折射率的因素进行了实验研究,确定了具有大折射率差的SiO₂/SiN_x材料的PECVD沉积条件.根据理论计算分析,设计了四层SiO₂/SiN_x抗反膜结构,能够在70 nm的波长范围内实现低于10^-4的反射率  相似文献   

邻氯苯基荧光酮胶束光度法测定氮化硅中镁的研究     

陈同森  赵欣 《岩矿测试》1994,13(4):254-258

研究了在氯化十六烷基吡啶（ＣＰＣ）和乳化剂ＯＰ存在下，Ｍｇ与邻氯苯基荧光酮（ｏ－Ｃｌ－ＰＦ）的显色反应。在ｐＨ１２的碱性介质中，Ｍｇ（Ⅱ）与ｏ－Ｃｌ－ＰＦ形成１：３的蓝色配合物，其λ＿ｍａｘ＝６１２ｎｍ，表现摩尔吸光系数ε＿６１２＝１．３９×１０￣５Ｌ·ｍｏｌ￣－１·ｃｍ￣－１，Ｍｇ（Ⅱ）在０～０．２μｇ／ｍｌ范围内符合比尔定律。方法用于新陶瓷材料氮化硅（Ｓｉ＿３Ｎ＿４）中微量ＭｇＯ的测定，其结果与原子吸收光谱法相符。  相似文献   

氮化硅陶瓷空心浮力球在内爆临界状态下的失效分析     

张晓龙  冯淼林  赵敏  张培志  何成贵  祁海  韩伟月  郭方全 《海洋工程》2020,38(6):70-76

氮化硅陶瓷具有密度小强度高的优点,在深潜浮力设备领域具有广阔发展前景。然而陶瓷材料固有的脆性以及万米深海严苛的工作环境,使得氮化硅陶瓷空心浮力球在深水环境下面临着内爆的风险。为探究氮化硅陶瓷空心浮力球在内爆临界状态下的失效问题,设计并进行了三点弯曲试验,确定了氮化硅陶瓷材料的力学性能参数,包括弹性模量和破坏应力;随后对氮化硅陶瓷空心浮力球内爆试验的过程及结果进行了回顾总结;基于标准球壳模型与浮力球实物的CT扫描几何模型,对浮力球在内爆临界状态的失效过程进行了有限元仿真分析。结果表明：氮化硅陶瓷空心浮力球的性能存在一定不稳定性;结构内表面局部过大的拉应力是造成失效的主要原因,对内表面进行预加压处理或能提高其抗内爆性能。  相似文献