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介绍了透明MgAl2O4陶瓷的优异性能及应用领域,综述了该陶瓷烧结工艺的最新研究进展,包括热压烧结/热等静压烧结、常压烧结、放电等离子烧结、微波烧结,并对透明MgAl2O4陶瓷离子掺杂及纳米透明MgAl2O4陶瓷的研究现状进行了介绍,展望了透明MgAl2O4陶瓷的研究方向. 相似文献
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α-Al2O3颗粒形貌及其陶瓷显微结构的分析 总被引:1,自引:0,他引:1
陶瓷是由压制坯体经高温烧制而成的.坯体由颗粒压制而成,所以陶瓷的烧结不仅是颗粒之间的烧结行为,更重要的是坯体的烧结行为.烧结是陶瓷烧成的重要环节.影响坯体烧结的因素相当多,其内在因素是粉末的特性.粉末特性是影响烧结的重要因素之一.表面能是颗粒烧结驱动之一,形貌对颗粒的表面能影响很大,所以颗粒形貌对陶瓷烧结的影响是相当大的.为了陶瓷的竞争力,研究者正在对既性能好又价格便宜的原料进行研究.人们对颗粒团聚体和颗粒大小影响烧结进行了大量的研究[1~5],但颗粒形貌对坯体烧结性能影响的研究很少. 相似文献
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纳米粉添加剂对Al2O3陶瓷烧结性能及微结构的影响 总被引:5,自引:0,他引:5
用纳米ZrO3作为烧结助剂加入Al2O3陶瓷中,研究其对Al2O3陶瓷烧结性能及显微结构的影响。结果表明,纳米ZrO2的加入可以提高Al2O3陶瓷的烧结活性,降低烧结温度,当纳米ZrO2的加入量达到9vol%时,Al2O3陶瓷在1600℃以下就可烧结致密,此外,纳米ZrO2的加入,对Al2O3陶瓷的显微结构也产生影响。在纳米ZrO2加入量较少时,ZrO2粒子以“晶内型”和晶界型两种形式存在;而当ZrO2加入量达到9vol%时,其主要位于四个Al2O3晶粒相交的晶界上,阻碍了Al2O3晶粒的异常长大,从而获得细晶结构的Al2O3陶瓷材料。 相似文献
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纳米复相陶瓷被认为是二十世纪最有发展前途的陶瓷材料之一。在陶瓷基体中弥散亚微米级的第二相颗粒,可使材料的机械性能大幅提高。显微观察发现了区别于微米级复合陶瓷的“内晶型”粒子的存在,这意味着纳米复合陶瓷性能的改善与其特殊的微观结构是密切相关的。其中Al2O3/SiCp是研究最多的系统,但由于弥散相SiC为共价键,很难烧结,因而Al2O3/SiCp纳米复相陶瓷一般用热压烧结[1—5]。但由于热压烧结成本昂贵,制品形状简单,极大地限制了其实用性。本文利用非均匀成核法,将Y(OH)3包覆到纳米SiC的粒子表面制备出Al2O3-SiC复合粉,等静压成… 相似文献
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The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde. 相似文献
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解决IP网QoS问题是目前通信领域的研究热点之一.虽然研究已经取得了一定的进展,但人们对于IP 网QoS本身的含义及相关的问题还有着不同的理解.本文将从IP网QoS的定义入手讨论相关的一些问题以及解决IP网QoS问题所做的各种努力. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1968,56(6):1024-1032
Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature. 相似文献
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By means of exact conformal mapping method we have defined character of dependence of squares amounts of angular part of film
element on angled part dimension. We propose relations, approximating obtained dependence. Calculation results and experimental
researches of large-scale models are represented. 相似文献
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A. M. Emel’yanov 《Semiconductors》2010,44(9):1134-1139
A method for analyzing the luminescence spectra of semiconductors is suggested. The method is based on differentiation of
the spectra. The potentialities of the method are demonstrated for luminescence in the region of the fundamental absorption
edge of Si and SiGe alloy single crystals. The method is superior in accuracy to previously known luminescence methods of
determining the band gap of indirect-gap semiconductors and practically insensitive to different conditions of outputting
radiation from the sample. 相似文献
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“计算机组成原理”设计性实践教学模式研究 总被引:1,自引:0,他引:1
本文阐述了"计算机组成原理"设计性实验教学的重要性,对设计性实验教学的目的和基本特征进行了归纳,对"计算机组成原理"设计性实验教学的现状进行了调查,对存在的问题进行了较深入的分析;在此基础上.对组成原理设计性实验的教学模式进行了研究,对设计性实验的体系进行了初步设计,并对"计算机组成原理"设计性实验的实施方法进行了探讨. 相似文献