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The nanometer TiO2 was prepared by pyrohydrolysis with titanic solution.The effects of species and content of the surfactants on the particle size,morphology and phase of TiO2 were studied by using LPA,XRD and TEM respectively.The results show that it is beneficial to reducing the aggregation of TiO2 particles with adding surfactants to the solution.Nanometer TiO2 powders with the size of 40-55 nm are obtained by adding the anion surfactants in the optimal content of 1.5%(mass fraction).The effect of cationic surfactant for reducing particle aggregation is not as good as that of anion.The crystal phase constitutent of TiO2 is dependent on the temperature of thermal treatment and complete anatase can be achieved after calcining in the temperature range of 350-750℃. 相似文献
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目标检测作为计算机视觉的重要研究方向,在智慧城市、无人驾驶等领域的作用越来越重要.传统目标检测算法中,根据交并比(Intersection over Union,IOU)的大小判断正负样本,但较低的IOU会引入噪声,降低检测器的精度;较高的IOU会保留少数高质量样本,造成过拟合;并且推荐区域和检测器的IOU阈值相差过大... 相似文献
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Modification of nano-TiO2 by Al2O3 in-situ coating 总被引:1,自引:0,他引:1
A novel technology of in-situ coating Al2O3 on the surface of H4TiO4 was developed to prevent the aggregation of nano-TiO2 powders and improve the dispersibility and thermal stability in the way of forming a uniform coating layer. The heterogeneous nucleation was conducted to prepare the precursor of nano-TiO2 and then Al2O3 was coated on the surface of precursor. The effects of Al2O3 in-situ coating on the properties of nano-TiO2 were investigated. The results show that H4 TiO4 can be dispersed well under alkaline condition (pH 8. 5) and the heterogeneous nucleation can be controlled easily. The optimized uniform coating layer is obtained by adding 5 % (mass fraction ) and 10% of Al2O3 and the aggregation of nano-TiO2 powders is effectively inhibited and the dispersibility is obviously improved. The crystal sizes of TiO2 powders are 12.3, 11.4 and 8. 7 nm after coating 0, 5% and 10% of Al2O3 respectively. Al2O3 on the surface of particulates in amorphous phase could increase the thermal stability of nano-partieles after calcined at 550℃. 相似文献
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江西某红土镍矿冶炼炉渣作水泥混合材 总被引:2,自引:0,他引:2
研究了江西某红土镍矿冶炼炉渣作为水泥混合材使用的可行性。研究结果表明:炉渣放射性和浸出毒性远小于国家标准限值,不具有危险性,属于一般工业固体废物,作为建筑材料原料不会影响产品使用;炉渣火山灰活性合格,具有潜在的水硬性,是一种活性混合材;经稳定化处理后,掺加炉渣的水泥压蒸安定性合格,随着炉渣掺量的增加,水泥胶砂强度逐渐降低;对不掺炉渣和掺入30%炉渣的净浆28 d试块的XRD图谱和SEM图谱进行了分析,指出了对净浆试块性能产生影响的原因。 相似文献
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Antibacterial powders of titanium dioxide/silver sulfate were produced by heat-treatment of the metatitanic acid, as precursor, into which the silver nitrate was added. The influences of heating temperature on the structure and composition of the product were investigated through XRD and SEM. The results show that the powder is spherical in the phase of TiO2-Ag2 SO4. The granularity of the particles increases from 10.7 nm to 28.7 nm with the temperature of heat-treatment increasing from 300 ℃ to 800 ℃. The antibacterial activity of the powder was judged in the way of the minimum inhibitory contents (MiCs). When the content of silver sulfate is less than 2%, the photocatalysis of titanium dioxide and silver ions cooperate to kill bacteria. And the MiCs decrease and keep around 1.0× 10-4- 1.5 × 10-4 constantly with the increase of silver content. Furthermore, the MiCs decrease with the increase of temperature of heat-treatment when the temperature is lower than 500 ℃. But when the temperature is beyond 600 ℃ the MiCs increase quickly, which shows the inferior antibacterial performance. 相似文献
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载银二氧化钛光催化杀菌性能的研究 总被引:7,自引:1,他引:7
以偏钛酸为前驱体,浸渍一定浓度的硝酸银溶液,用热沉积法制备出载银二氧化钛。用XRD测定载银二氧化钛的结构,扫描电镜观测形貌,研究了载银量、光强、二氧化钛浓度、细菌浓度对光催化杀菌的影响。结果表明:制备的粉体为超细锐钛矿型二氧化钛,颗粒为均匀的类球形,粒度约为100~200nm。在二氧化钛颗粒上负载约1.6%的银可以扩展光源利用范围至可见光,光催化作用与银协同杀菌;但银量过高,则主要体现银的杀菌效果。光强增加,杀菌效果提高;二氧化钛的浓度为1.5g/L时杀菌效果最好;细菌浓度低于106细胞/mL时,载银二氧化钛杀菌率可以达到90%以上。 相似文献