共查询到20条相似文献,搜索用时 78 毫秒
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目的:建立骨皮质切开术辅助组牙压低的动物实验模型,并观察实验牙移动速度及牙根、牙周组织的改变。方法:选取雄性Begle犬2条,设定下颌第三、四前磨牙为实验牙,随机取一侧为实验侧,对侧为对照侧,以第二磨牙为空白对照。在实验侧施行骨皮质切开术,一月后,以微种植体为支抗,加力压低双侧实验组牙。持续加力30天将动物处死取材,标本经HE染色处理后进行结果观察。结果:实验动物均耐受手术。在组牙压人过程中,实验侧牙齿较对照侧有更大程度的压低,实验侧实验牙根尖区的牙根吸收和牙周膜的透明样变较对照侧轻,但实验侧牙槽骨观察到的破骨吸收现象更明显。结论:以微种植体为支抗建立的骨皮质切开术辅助组牙压低的动物模型科学、可靠,为进一步研究提供了较好的平台。 相似文献
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大鼠胫骨、股骨颈、骨松质及人骨髓活检标本,经戊二醛固定后,用戊二醛-EDTA脱钙液,选择不同微波功率及时间进行脱钙。结果为微波功率420W作用1min加70W8-10min共3-4次,既能达到脱钙目的,又能保存好细胞超微结构,分别适于几种硬度骨标本的电镜快速制样。 相似文献
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本文用,经化学和物理方法系列处理,与骨组织有高度亲和性的陶瓷化牛骨和用化学法部分提纯的牛骨骨诱导蛋白(骨形态发生蛋白,Bone Morphogeritic Protein,BMP),复合移植修复24只狗的下颌骨实验性骨缺损。通过扫描电子显微镜,从一周至一年不同间期的系列观察。证明,这种异种骨复合植骨材料组织相容性好、骨诱导力强。复合骨移植后一周,间质细胞趋化,部分转化为成软骨细胞和成骨细胞。二周有软骨基质和类骨质形成。四周骨基质开始钙化。随着时间延长,骨胶原不断长入移植骨微孔内,钙化基质将移植骨羟磷灰石结晶分隔、包埋。最终,新骨和移植骨融为一体,达到骨愈合[图1]。 相似文献
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几种骨标本微波快速脱钙的电镜实验研究 总被引:2,自引:0,他引:2
大鼠胫骨、股骨颈、骨松质及人骨髓活检标本 ,经戊二醛固定后 ,用戊二醛 EDTA脱钙液 ,选择不同微波功率及时间进行脱钙。结果为微波功率 4 2 0W作用 1min加 70W 8~ 10min共 3~ 4次 ,既能达到脱钙目的 ,又能保存好细胞超微结构 ,分别适于几种硬度骨标本的电镜快速制样 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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Moshrefzadeh R.S. Radcliffe M.D. Lee T.C. Mohapatra S.K. 《Lightwave Technology, Journal of》1992,10(4):420-425
The temperature dependence of refractive index of polymer films was determined for a number of slab waveguides by a grating coupling method. This dependence was examined as a function of parameters such as molecular weight and glass transition temperature of the polymer. Temperature-induced changes in N TE-N TM , N being the effective index, were studied systematically for different slab waveguide compositions. It is shown that with proper device design and choice of polymeric materials, thermal effects can be reduced 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