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利用正交试验研究了水胶比、砂灰比、石英粉掺量、硅灰掺量、粉煤灰掺量和钢纤维掺量对活性粉末混凝土(RPC)抗折强度和抗压强度的影响。通过较少的试验次数获得了RPC的较佳配合比。 相似文献
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以麦饭石为载体、Ag+和Zn2+为抗菌离子,通过液相离子交换反应,制备载银锌的麦饭石无机抗菌剂。采用抑菌率对所得产物的抗菌性进行检测,采用XRD、SEM对产物的结构与形貌进行表征,并采用缓释法对产物的耐久性进行研究。实验结果表明:在反应时间为4 h,反应温度为60℃,Ag+和Zn2+浓度分别为0.1、2 mol·L-1,pH值为8的条件下,制备的麦饭石抗菌剂具有优异抗菌性和耐久性。抗菌机理初步分析为通过离子交换或吸附进入麦饭石结构内的Ag+和Zn2+能从载体中持久缓慢地释放出来,与细菌细胞作用,杀灭细菌,从而保持该抗菌剂良好的抗菌能力。 相似文献
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Boron nitride nanotubes (BN-NTs) with pure hexagonal BN phase have been synthesized by heating ball-milled boron powders in flowing ammonia gas at a temperature of 1200℃. The as-synthesized products were characterized by X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and electron energy loss spectroscopy (EELS). The diameters of nanotubes are in the rage of 40-120nm and the lengths are more than 10μm. EELS result identifies that the ratio of boron and nitrogen is almost 1:1 The growth temperature is a crucial growth parameter in controlling the structure and crystalline of BN-NTs. The nanotubes grown at 1100℃ possesses of a bamboo-like structure, while as the temperature increased to 1200℃, most of the nanotubes exhibited a cylindrical structure. In addition, changing the heating time can control the size of the nanotubes. The gas atmosphere has influence on the yield of BN-NTs during heating process. When heating atmosphere was replaced by nitrogen, the yield of nanotubes was remarkably decreased. 相似文献
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以石墨粉和硼粉为原料,采用机械球磨法,在氨气气氛下球磨120h,然后在1200℃氨气条件下热处理6h, 成功的制备出竹节状的B-C-N纳米管.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)、高分辨透射电子显微镜(HRTEM)以及电子能量损失谱(EELS)等手段进行了表征.纳米管的直径在50~180nm之间,长度可达20μm. EELS定量分析计算结果表明,纳米管由硼、碳和氮元素组成, 其B∶C∶N原子比为0.49∶1.00∶0.11,并对纳米管的形成机理进行了初步探讨. 相似文献
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本文采用正交设计的方法,对粉煤灰在预应力轨枕高性能混凝土中的应用进行了试验研究。探讨了粉煤灰、减水剂及UEA膨胀的掺量对混凝土的工作性、强度等性能的影响,得出了配制C60轨枕混凝土的最佳配比方案,评价了粉煤灰在预应力轨枕混凝土中的利用价值。 相似文献
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