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科技正在不断革新,为人们的生活带来了诸多便利,同时也带来了严重的环境问题。臭氧层的损坏造成的酸雨已经成为了全球性问题,其不仅对于动植物同时对于建筑也有巨大伤害,酸雨可以大面积腐蚀建筑,对于工业建筑的腐蚀情况尤为严重,因为工业建筑在很多情况下自身含有一定的腐蚀物质,这些可以加剧在酸雨降下时的腐蚀程度。所以想要改善这样的情况,需要在不影响工业建筑使用效果的情况下,引进合适的技术,来增强工业建筑的防腐蚀能力,这样的做法是对建筑与人员的双重保护。 相似文献
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基于知识工程的用户特征零部件库的开发与应用 总被引:6,自引:0,他引:6
针对制造企业中通常存在着大量本领域产品的特征零部件,设计人员需要经常对其进行变形设计的实际情况,介绍了基于知识工程的用户自定义特征零部件库的开发和应用方法,为企业实现设计知识的存储与重用,提高设计效率、改进设计质量,进一步实现智能化快速响应设计打下了基础. 相似文献
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Ca10(PO4)6(OH)2纳米粉体的制备及TEM分析 总被引:6,自引:0,他引:6
采用化学沉淀法合成纳米羟基磷灰石粉体,考察了工艺参数一反应物浓度和反应温度对纳米粉体的粒度和结晶度的影响。用等离子发射光谱、红外光谱、X射线衍射和透射电镜等实验手段对粉体的粒度和表面形貌进行了表征。结果表明:反应温度是影响纳米颗粒粒度和结晶度的主要因素,通过控制反应温度可以得到不同粒度的纳米颗粒。37℃下合成的纳米颗粒尺寸接近人体骨的纳米结晶(30~40nm),75℃下合成的纳米颗粒尺寸接近牙釉质的纳米结晶(150~170nm)。醇洗可以有效地改善沉淀法合成的纳米羟基磷灰石粉体的分散性。 相似文献
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The growing necessity of biomaterials has increased the interest in hydroxyapatite. Small differences in particle sizes, stoichiometry, morphology, crystallinity could lead to different clinical behaviors. In the present work, stoichiometry and nanocrystal hydroxyapatite were prepared by wet chemical precipitation method. The effects of concentration of reagents, reaction temperatures and reaction time were studied. Transmission Electron Microscopy, Electron Diffraction, X - ray Diffraction, Fourier Transform Infrared Spectroscopy, arid Inductively Coupled Plasma Spectroscopy were used to characterize the precipitated hydroxyapatite powders. X - ray Diffraction and TEM micrographs results showed that crystallinity, morphology and particle sizes were largely dependent on reaction temperature. Chemical analysis showed that the purity of the precipitated hydroxyapatite depends on reaction time and reaction temperature. Degree of supersaturation and stirring could affect the crystallization process. Particles showed acicular morphology, and had a size of 20 - 30 nm in length at 20 ℃ and 37 ℃ and 150 - 160 nm in length at 75 ℃. Particles were monocrystalline at 20 ℃ and 37 ℃ , and were polycrystalline at 55 ℃ and 75 ℃. The results showed that hydroxyapatite powders with different particle size and morphology could be obtained with carefully controlled reaction conditions. 相似文献
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针对磨粒显微图像识别中的目标提取问题 ,应用一种新的阈值分割方法将磨粒目标从复杂背景中分离。该算法以原始图像与分割后图像的相关系数最大为准则 ,选取最优阈值对磨粒图像进行二值化 ,经腐蚀、膨胀等滤波运算后 ,利用跟踪搜索法提取磨粒边界 ,实现了复杂背景下磨粒目标的有效提取。应用实例表明了算法的简洁有效性。 相似文献
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