共查询到19条相似文献,搜索用时 156 毫秒
1.
铯铅卤化物钙钛矿纳米晶是光伏和发光应用领域中理想化的三线态敏化材料,具有较高的荧光量子产率和量子限域效应。以三层厚度的CsPbBr3纳米片(NPLs)为三线态给体,实现了从NPLs到1-萘甲酸(NCA)分子的高效三线态能量传递(TET)。CsPbBr3 NPLs采用配体辅助再沉淀方法制备,其与NCA分子结合后,稳态荧光被大幅淬灭,荧光寿命从复合前的6.743 ns缩短到0.995 ns,TET效率达到85.3%。通过与大尺寸纳米立方体对比发现,对于CsPbBr3-多环芳烃复合体系,量子限域效应是获得高效TET的关键。研究结果表明,CsPbBr3 NPLs作为三线态敏化剂,可应用在基于TET的光子上转换、光催化氧化-还原反应和室温磷光等领域。 相似文献
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针对硫化铅(PbS)特殊的三阶非线性光学特性,本文在水溶液里合成了PbS纳米粒子.紫外-可见光谱显示,由于使用了封端剂,合成的样品更加稳定.用紫外-可见吸收光谱和X射线衍射斑研究了PbS纳米粒子的特性,结果表明,由于纳米粒子尺寸减小,其吸收光谱显示极大的蓝移.利用Seherre方程估计PbS粒子的平均粒径约为8.2 n... 相似文献
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为了实现在无外部供能下对紫外光的有效探测,基于Ag修饰的Bi2O3纳米块(Ag/Bi2O3)纳米块制备了自供能紫外探测器。通过煅烧法制备Bi2O3纳米块,随后采用室温溶液法在其表面沉积Ag纳米粒子,进而成功制备了Ag/Bi2O3纳米块,且对所制备样品的晶体结构和微观形貌等进行了表征。结果表明,Ag/Bi2O3纳米块的平均尺寸约为1μm,且Ag纳米粒子随机分布在Bi2O3纳米块表面。将涂覆Ag/Bi2O3纳米块的FTO作为工作电极,并进一步构建了自供能紫外探测器。在365 nm的紫外光照射下,Ag/Bi2O3纳米块紫外探测器能在零偏压下实现对紫外光的快速检测,这证实其具有自供能特性。相比于Bi2O3... 相似文献
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以FeSO4·7H2O和CH3COONa·3H2O为原料,采用水热方法制备α-FeOOH纳米棒,将所得α-FeOOH纳米棒于250℃烧结2 h制备α-Fe2O3纳米棒,采用差热-热重分析法研究了制备的α-FeOOH和α-Fe2O3纳米棒对高氯酸铵热分解的催化性能。结果表明:在100℃水热反应6 h可制备得到平均直径为18 nm的纯相α-FeOOH纳米棒,再于250℃烧结2 h后获得平均直径为16 nm的纯六方相α-Fe2O3纳米棒;α-Fe2O3和α-FeOOH纳米棒对高氯酸铵热分解的催化效果显著,添加质量分数2%的α-Fe2O3纳米棒和α-FeOOH纳米棒可使高氯酸铵的结束分解温度分别降低40,54℃,高温分解峰值温度分别降低51.1,61.6℃;当α-Fe2... 相似文献
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文中以In(NO3)3·4.5H2O为铟源,KMnO4为锰源,PVP为添加剂,分别以水和无水乙醇为溶剂,通过两步水热法成功合成了In2O3-Mn2O3复合纳米棒。采用XRD、SEM、XPS对复合材料的物相组成、微观形貌和元素价态进行了表征和分析,并将In2O3-Mn2O3复合材料组装成气敏传感器元件进行氢气的气敏性能研究。结果表明,相比于In2O3,In2O3-Mn2O3传感器的最佳工作温度降低至325℃,且In2O3-Mn2O3传感器在重复性实验中对氢气具有高灵敏度,优异的选择性、重复性和稳定性。复合材料表面... 相似文献
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以柠檬酸为修饰剂在水溶液中合成表面修饰LaF3纳米微粒,通过X射线衍射(XRD)、傅立叶变换红外光谱(FTIR)、热重分析(TG-DTA)、激光粒度分布仪、透射电子显微镜(TEM)、X射线光电子能谱仪(XPS)等测试手段对其结构和形貌进行表征;采用四球摩擦磨损试验机考察LaF3纳米微粒作为添加剂时的摩擦学行为;采用X射线光电子能谱仪(XPS)分析钢球磨损表面的元素组成。结果表明,柠檬酸修饰的LaF3纳米微粒,平均粒径约为4 nm;LaF3纳米微粒在水中的分散性良好,作为水基添加剂,在摩擦过程中可在钢摩擦副表面的形成由Fe2O3、La2O3等为主要组成部分的边界润滑膜,因此表现出极好的抗磨减摩性能,具有很好的应用前景。 相似文献
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选用菜籽油、失水山梨糖醇脂肪酸酯(Span 80)、壬基酚聚氧乙烯醚(TX-7)、正丁醇制备W/O型微乳液,并将其作为微反应器原位合成CaCO3微纳米粒子。对CaCO3粒子形貌的表征表明,随含水量增加,CaCO3粒子由球形转变为梭形薄片状,CaCO3粒子尺寸也可受含水量控制。通过四球摩擦磨损试验机评价CaCO3微纳米流体的摩擦学性能,结果表明,该微乳液体系相较于基础油的摩擦因数降低了约55.74%,CaCO3粒子使微乳液PB值提高了约10.88%,摩擦面粗糙度降低了约16.01%。在摩擦过程中,胶团在表面活性剂的作用下平行吸附于摩擦面且易于剪切,实现优异的减摩效果;梭形薄片状的CaCO3微纳米粒子可以抑制表面微凸体之间的直接接触,减少黏着磨损与磨粒磨损,从而发挥极压作用并显著改善表面质量。 相似文献
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采用挤出混合与注塑成型制备出不同含量的纳米Al2O3填充LDPE/POM复合材料,并进行力学和摩擦磨损性能实验。结果表明,随着纳米Al2O3的增加,LDPE/POM复合材料的缺口冲击性能先提高后降低,其中添加8%纳米Al2O3后复合材料的缺口冲击强度提高了近3倍;添加Al2O3纳米粒子后增加了复合材料的摩擦因数,但对耐磨性影响不大。由于纳米Al2O3作为刚性粒子可以提高材料的硬度,因此复合材料仍表现出良好的耐磨性;然而纳米粒子在摩擦表面富集,产生了犁沟现象,因此提高了材料的摩擦因数。 相似文献
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Sliding wear characteristics of plasma-sprayed Al2O3 and Cr2O3 coatings against copper alloy under severe conditions 总被引:2,自引:0,他引:2
Al2O3 and Cr2O3 coatings were deposited by atmospheric plasma spraying and their tribological properties dry sliding against copper alloy were evaluated using a block-on-ring configuration at room temperature. It was found that the wear resistance of Al2O3 coating was superior to that of the Cr2O3 coating under the conditions used in the present study. This mainly attributed to its better thermal conductivity of Al2O3 coating, which was considered to effectively facilitate the dissipation of tribological heat and alleviate the reduction of hardness due to the accumulated tribological heat. As for the Al2O3 coating, the wear mechanism was plastic deformation along with some micro-abrasion and fatigue-induced brittle fracture, while the failure of Cr2O3 coating was predominantly the crack propagation-induced detachment of transferred films and splats spallation. 相似文献
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ZrO2 (Y2O3) with different contents of BaF2/CaF2 and Mo were fabricated by hot pressed sintering, and the tribological behavior of the composites against SiC ceramic was investigated from room temperature to 1000 °C. It was found that the ZrO2 (Y2O3)-5BaF2/CaF2-10Mo composite possessed excellent self-lubricating and anti-wear properties. The low friction and wear were attributed to enhanced matrix and BaMoO4 formed on the worn surfaces. 相似文献
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Influence of Al2O3 reinforcement on the abrasive wear characteristic of Al2O3/PA1010 composite coatings 总被引:2,自引:0,他引:2
In the present study, the abrasive wear characteristics of Al2O3/PA1010 composite coatings were tested on the turnplate abrasive wear testing machine. Steel 45 (quenched and low-temperature tempered) was used as a reference material. The experimental results showed that when the Al2O3 particles have been treated with a silane coupling agent (γ-aminopropyl-triethoxysilane), the abrasive wear resistance of Al2O3/PA1010 composite coatings has a good linear relationship with the volume fraction of Al2O3 particles in Al2O3/PA1010 composite coatings and the linear correlation coefficient is 0.979. Under the experimental conditions, the size of Al2O3 particles (40.5-161.0 μm) has little influence on the abrasive wear resistance of Al2O3/PA1010 composite coatings. By treating the surface of Al2O3 particles with the silane coupling agent, the distribution of Al2O3 particles in PA1010 matrix is more homogeneous and the bonding state between Al2O3 particles and PA1010 matrix is better. Therefore, the Al2O3 particles make the Al2O3/PA1010 composite coatings have better abrasive wear resistance than PA1010 coating. The wear resistance of Al2O3/PA1010 composite coatings is about 45% compared with that of steel 45. 相似文献
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Very little research effort has been directed at development of models of erosion–corrosion of composite materials. This is because, in part, the understanding of the erosion–corrosion mechanisms of such materials is poor. In addition, although there has been a significant degree of effort in the development of models for erosion of MMCs, there are still difficulties in applying such models to the laboratory trends on erosion rate.In this paper, the methodology for mapping erosion–corrosion processes in aqueous slurries was extended to particulate composites. An inverse rule of mixtures was used for the construction of the erosion model for the particulate MMCs. The corrosion rate calculation was evaluated with reference to the matrix material.The erosion–corrosion maps for composites showed significant dependency on pH and applied potential. In addition, the corrosion resistance of the matrix material was observed to affect the regime boundaries. Materials maps were generated based on the results to show the optimum composite composition for exposure to the environment. 相似文献
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Al2O3–50BaSO4–20Ag, Al2O3–50BaSO4–10SiO2, Al2O3–50(mass%)SrSO4, Al2O3–50PbSO4–5SiO2, Al2O3–50BaSO4 and Al2O3–50BaCrO4 composites (mass%) were prepared by spark plasma sintering and their microstructure and high-temperature tribological properties were evaluated. Al2O3–50BaSO4–20Ag composites (mass%) showed the lowest friction coefficients at the temperature ranging from 473 to 1073 K. Thin Ag film was observed on the wear tracks of the composites above 473 K. In addition, the friction coefficients of Al2O3 composites containing SrSO4 and PbSO4 were as low as those of Al2O3–BaSO4 and Al2O3–BaCrO4 composites at the temperatures up to 1073 K. The thin films formed on the wear tracks of the Al2O3–SrSO4 composites were composed of Al2O3 and SrSO4 phases, while the films formed on the wear tracks of the Al2O3–PbSO4–SiO2 composites consisted of Al2O3, PbSO4 and SiO2 phases. 相似文献
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This study consists of two stages. In the first stage, bronze-based break linings were produced and friction-wear properties of them were investigated. In the second stage, 0.5%, 1%, 2% and 4% alumina (Al2O3) powders were added to the bronze-based powders and Al2O3 reinforced bronze-based break linings were produced. Friction–wear properties of the Al2O3 reinforced samples were aslo investigated and compared to those of plain bronze-based ones. For this purpose, friction coefficient and wear behaviour of the samples were tested on the grey cast iron disc. The hardness and density of the samples were also determined. Microstructures of the samples before and after the sintering and the worn surfaces of the wear specimens were examined using a scanning electron microscope (SEM). The sample compacted at 350 MPa and sintered at 820 °C exhibited the optimum friction–wear behaviour. With increase in friction surface temperature, a reduction in the friction coefficient of the samples was observed. The lowest reduction in the friction coefficient with increasing temperature was for the 2% and 4% Al2O3 reinforced samples. The SEM images of the sample indicated that increase in Al2O3 content resulted in adhesive wear. With increase in Al2O3 content, a reduction in mass loss of the samples was also observed. Overall, the samples reinforced with 2% and 4% Al2O3 exhibited the best results. 相似文献
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Study on the tribological behavior of hybrid PTFE/cotton fabric composites filled with Sb2O3 and melamine cyanurate 总被引:1,自引:0,他引:1
The tribological behavior of the hybrid PTFE/cotton fabric composites filled with microsize Sb2O3 and melamine cyanurate (MCA) was investigated. It was found that the wear rate of the hybrid PTFE/cotton fabric composites decreased when Sb2O3 was used as the filler but increased with MCA filler. It was also observed that hybrid fillers (consists of Sb2O3 and MCA) had a wear reduction effect on the hybrid PTFE/cotton fabric composites at lower loads but increased the wear rate at higher loads. The wear behavior of the composites was explained in terms of the topography of worn surfaces and transfer film formed on the counterpart pin. 相似文献
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采用太赫兹散射式扫描近场光学显微镜(THz s-SNOM)研究了化学气相沉积法制备的单层MoS2和WS2晶粒的太赫兹近场响应。在没有可见光激发时,未探测到可分辨的太赫兹近场响应,说明晶粒具有较低的掺杂载流子浓度。有可见光激发时,由于光生载流子的太赫兹近场响应,能够测得与晶粒轮廓完全吻合的太赫兹近场显微图。在相同的光激发条件下,MoS2的太赫兹近场响应强于WS2,反映了两者之间载流子浓度或迁移率的差异。研究结果表明,THz s-SNOM兼具超高的空间分辨率和对光生载流子的灵敏探测能力,对二维半导体材料和器件光电特性的微观机理研究具有独特的优势。 相似文献
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Shufang Ren Junhu Meng Jinjun Lu Shengrong Yang Jingbo Wang 《Tribology International》2010,43(1-2):512-517
The tribological behaviors of tungsten carbide (WC) based cermet/Ti3SiC2 tribo-pair at elevated temperatures were investigated. Lead oxide (PbO) was added as a solid lubricant. The tribo-physical and tribo-chemical changes on sliding surfaces were studied in detail. The results indicated that adhesive and abrasive wear due to removal of metallic binder and pullout of grains were the dominant wear mechanisms at room temperature. At high temperature, tribo-physical changes (i.e. mechanical mixture or sintering) and tribo-chemical reactions including complex reaction and oxidations were induced by frictional heat combined with high environmental temperature. As a result PbWO4 was formed as a reaction product and acted as a solid lubricant. PbWO4 and tribo-oxides along with the physically changed layer on the sliding surfaces were favorable to reduce wear of both materials. At high temperature, the wear mechanism varied from adhesive and abrasive wear at room temperature to lubrication by tribo-layer containing PbWO4, tribo-oxides, and sinters at high temperatures. 相似文献