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排序方式: 共有862条查询结果,搜索用时 15 毫秒
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ABSTRACT In this study, effect of calcium and gypsum on scheelite and fluorite was investigated using sodium oleate as collector. Micro-flotation and contact angle results showed that the adsorption of calcium could inhibit the hydrophobicity of scheelite and fluorite. Moreover, sulfate could enhance the inhibition. FT-IR results showed that calcium could be priori precipitated into calcium oleate and adsorb on mineral surface. The adsorption of calcium could increase the scheelite potential to IEP, while it showed limited effect on fluorite potential. However, the interaction of calcium on scheelite and fluorite in gypsum solution was more complex than that in calcium solution. 相似文献
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Haitang Yang Zilong Lu Bixiong Bie Zeyu Fu Jianling Yue Xiaozhong Huang 《Ceramics International》2019,45(9):11395-11402
SiCf/PyC/SiC and SiCf/BN/SiC mini-composites comprising single tow SiC fibre-reinforced SiC with chemical vapor deposited PyC or BN interface layers are fabricated. The microstructure evolutions of the mini-composite samples as the oxidation temperature increases (oxidation at 1000, 1200, 1400, and 1600?°C in air for 2?h) are observed by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction characterization methods. The damage evolution for each component of the as-fabricated SiCf/SiC composites (SiC fibre, PyC/BN interface, SiC matrix, and mesophase) is mapped as a three-dimensional (3D) image and quantified with X-ray computed tomography. The mechanical performance of the composites is investigated via tensile tests.The results reveal that tensile failure occurs after the delamination and fibre pull-out in the SiCf/PyC/SiC composites due to the volatilization of the PyC interface at high temperatures in the air environment. Meanwhile, the gaps between the fibres and matrix lead to rapid oxidation and crack propagation from the SiC matrix to SiC fibre, resulting in the failure of the SiCf/PyC/SiC composites as the oxidation temperature increases to 1600?°C. On the other hand, the oxidation products of B2O3 molten compounds (reacted from the BN interface) fill up the fracture, cracks, and voids in the SiC matrix, providing excellent strength retention at elevated oxidation temperatures. Moreover, under the protection of B2O3, the SiCf/BN/SiC mini-composites show a nearly intact microstructure of the SiC fibre, a low void growth rate from the matrix to fibre, and inhibition of new void formation and the SiO2 grain growth from room to high temperatures. This work provides guidance for predicting the service life of SiCf/PyC/SiC and SiCf/BN/SiC composite materials, and is fundamental for establishing multiscale damage models on a local scale. 相似文献
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地震数据采集系统中频谱均衡滤波器的理论设计 总被引:2,自引:0,他引:2
地层的高频吸收衰减效应是导致地震勘探分辨率不高的主要原因,在高分辨率野外地震数据系统中,频谱均衡滤波器所设置的重要部件。文章以频谱均衡滤波器的原理和地层吸收衰减特性为基础,用计算机模拟的方法研究地层吸收衰减使分辨率降低的程度和频谱均衡滤波器对分辨率的补偿效果,给出了较好的频谱均衡滤波器的设计方案。 相似文献
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Co^3+—modified Surface of LiMn2O4 Spinel for its Improvementof Electrochemical Properties 总被引:3,自引:0,他引:3
ZishanZHENG ZilongTANG ZhongtaiZHANG JunbiaoLU WanciSHEN 《材料科学技术学报》2003,19(4):359-362
Cobalt was used to modify the surface of spinel LiMn2O4 by a solution technique to produce Co^3 -modified surface material (COMSM). Cobalt was only doped into the surface of LiMn2O4 spinel. XPS(X-ray photoelectron spectroscopy) analysis confirms the valence state of Co^3 . COMSM has stable spinel structure and can prevent active materials from the corrosion of electrolyte. The ICP(inductively coupled plasma) determination of the spinel dissolution in electrolyte showed the content of Mn dissolved from COMSM was smaller than that from the pure spinel. AC impedance patterns show that the charge-transfer resistance (Rct) for COMSM is smaller than that for pure spinel. The particles of COMSM are bigger in size than those of pure spinel according to the micrographs of SEM(scanning electron microscopy). The determinations of the electrochemical characterization show that COMSM has both good cycling performance and high initial capacity of 124.1 mA/h at an average capacity loss of 0.19 mAh/g per cycle. 相似文献
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卜子龙 《计算机光盘软件与应用》2012,(2):117-118
为了满足近年来互联网的迅猛发展要求,网络硬件也随之不断升级。本文通过分析核心路由器的发展过程,就其体系结构设计等方面深入探讨了核心路由器的发展趋势以及前景。 相似文献
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采用原位碳包覆法制备了锂离子二次电池用LiFePO4/C复合正极材料。考察了环境温度对LiFePO4/C电池容量的影响,得到容量与绝对温度之间符合Arrhenius关系。运用交流阻抗谱分析了温度与电池电化学特性的关系,并对电极基于电荷和质量传递控制过程给出了一种新的模拟等效电路,通过Zview拟合软件得到了各个模拟元件的数值及变化趋势,从而定量地解释LiFePO4/C复合电极容量与温度的关系。 相似文献
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