共查询到20条相似文献，搜索用时 203 毫秒
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本文提出了一个GaAs/AlxGa1-xAs量子点量子阱的理论模型,并采用二能级模型对其尺寸相关的三阶极化率进行了计算.计算结果表明:对一个GaAs/AlxGa1-xAs盘状量子点量子阱,其三阶极化率的变化规律与量子点的径向尺寸的变化有密切关系. 相似文献
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随着体系尺寸减小到纳米级以及维度的降低,表面效应、量子限域效应、尺寸效应以及量子隧穿效应越来越显著,因而低维纳米材料通常表现出不同于普通块体材料的理化性质.第一性原理计算方法具有准确、高效、便捷以及低成本等优势,借助第一性原理计算方法,可以在原子与分子层面上设计、计算和分析新材料,在材料结构与性能计算相关领域,则可以准确预估各类材料的基本物性.因此第一性原理计算方法成为了除理论方法与实验方法外可以独立开展材料物性研究的第三种方法. 相似文献
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本文使用了紧致密度矩阵的方法,在有效质量近似下,对CdSe/ZnS核-壳结构的球型量子点中的光学克尔效应进行了研究.我们得到了不同核层半径R1和壳层厚度R2与量子点光学克尔效应三阶极化率x3ate谈施工的函数曲线,计算结果表明,在3nm-10nm的范围内,量子点的光学克尔效应强度和该量子点的尺寸密切相关. 相似文献
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应用分子动力学模拟的方法,研究了纳米金刚石颗粒的导热系数对温度和颗粒尺寸的依存关系。为了得到较为准确的模拟结果,采用了平衡态分子动力学模拟的方法。计算了较长时间的热流自相关函数,并得到了导热系数的收敛结果。结果表明,纳米金刚石颗粒由于尺寸的影响,导热系数低于体材料金刚石的导热系数;随温度的升高,导热系数出现一个峰值,该峰值点的温度小于体材料金刚石出现峰值点的温度;随颗粒尺寸的增大,导热系数增加,我们预测导热系数将在一定的颗粒尺寸时收敛于体材料金刚石的导热系数。 相似文献
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根据纳米锰材料的结构和结构缺陷的特点,运用团簇物理、化学理论的方法,通过研究纳米锰内部原子的排列,电子能带结构的形成和发展,分析了纳米锰结构中的表面、内部及界面现象,探讨了位错导致层错和形变孪晶的形成原因,为发现和制备新型纳米材料提供了一种理论方法和基础。 相似文献
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《百科知识》2015,(6)
<正>彩电市场永远不缺技术的亮点。4K电视、OLED电视、曲面电视等名词还没能让人们耳熟能详,2014年底,量子点电视又横空出世,成为引爆电视市场的新热点。TCL、长虹抢先发布新品,三星、索尼等知名品牌也纷纷表示将陆续推出量子点电视。什么是量子点?量子点是由锌、镉、硒和硫原子构成的肉眼看不到的、极其微小的半导体无机纳米晶体,其晶粒直径在2~10纳米之间,一般为球形或类球形。早在1983年,美国贝尔实验室的科学家就对这种晶体进行深入研究,数年后美国耶鲁大学的物理学家马克·里德正式将其命名为"量子点"。量子点的光电特性很独特,它受到电或光的刺激,会根据量子点的直径大小,发出各种不同颜色的纯正高质量单色光。量子点应用在显示技术上的主要原理是:通过纯蓝光源激发量子点光管中不同尺寸 相似文献
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纳米材料的广泛研究为纳米结构薄膜材料的开发和研究提供了坚实的基础.目前,利用自组装的方法制备类似生物材料的有序纳米结构,技术也已经较为成熟.本文采用聚乙二醇（PEG）作为有机添加剂,通过控制PEG的量,可以制备出更小尺寸和形状的二氧化钛薄膜纳米颗粒膜. 相似文献
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Nanotechnology has brought revolution in cancer detection and treatment. It has capability to detect even a single cancerous cell in vivo and deliver the highly toxic drugs to the cancerous cells. Nanoshells, carbon nanotubes, quantum dots, supermagnetic nanoparticles, nano wires, nanodiamonds, dandrimers, and recently synthesized nanosponges are some of the materials used for cancer detection. Using specific cross linkers, such as specific antibodies against cancer cells individual cancer cells can be located. With the aid of a novel set of lipid-coated, targeted quantum dots a method for quantifying multiple specific biomarkers on the surfaces of individual cancer cells was also developed. This approach to quantitative biomarker detection stands to improve the histopathology methods used to diagnosis pancreatic and other cancers and enable the development of methods to spot cancer cells circulating in the blood stream. Certain nano materials can also deliver cancer drugs at the site so the drug toxicity can also be reduced. 相似文献
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水稻对锗元素的吸收特性及其在体内分布规律的研究 总被引：7，自引：0，他引：7
在液培条件下研究了晚籼杂交组合汕优６３苗期吸收锗元素的某些特性，测定了该试材抽穗期锗元素在各器官间分布特征，并对Ｇｅ—Ｓｉ互作特征进行了研究．结果表明，溶解在营养液中的锗元素能迅速地为稻苗吸收并运往地上部，地上部（尤其是叶片和叶鞘）具有更强的锗元素富集能力，锗与硅两元素在吸收机制上存在竞争拮抗效应 相似文献
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提出一种离散化的光学层析成像方法用于提取检测物的纵向深度信息和光谱特性。利用液相的ZnSe量子点为光源,设计了分立的元件组成光学层析装置,提取了多层媒质的信息。在理论上分析了模型的有效性;在实验上,利用五层媒质验证了该方法的可行性。基于此方法的研究可以广泛地应用于光学成像、生物芯片等许多领域。 相似文献
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根据国际半导体技术蓝图(ITRS)发布的未来半导体工艺技术预测,2016年世界集成电路主流工艺线宽为22纳米,2022年达到10纳米。届时,以硅为基础的微电子技术发展所遵循的摩尔定律将不再适用;为此,必须发展基于全新原理的新技术,以满足人类不断增长的对信息量的需求。本文首先介绍硅材料国内、外的发展现状与趋势,进而讨论后摩尔时代的微电子技术发展可能采取的对策,最后展望基于全新原理的纳米电子、分子电子、光计算和量子信息技术的发展前景。 相似文献
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Xinyu Wang Jiahua Pu Yi Liu Fang Ba Mengkui Cui Ke Li Yu Xie Yan Nie Qixi Mi Tao Li Lingli Liu Manzhou Zhu Chao Zhong 《国家科学评论(英文版)》2019,6(5):929
Nanoscale objects feature very large surface-area-to-volume ratios and are now understood as powerful tools for catalysis, but their nature as nanomaterials brings challenges including toxicity and nanomaterial pollution. Immobilization is considered a feasible strategy for addressing these limitations. Here, as a proof-of-concept for the immobilization of nanoscale catalysts in the extracellular matrix of bacterial biofilms, we genetically engineered amyloid monomers of the Escherichia coli curli nanofiber system that are secreted and can self-assemble and anchor nano-objects in a spatially precise manner. We demonstrated three scalable, tunable and reusable catalysis systems: biofilm-anchored gold nanoparticles to reduce nitro aromatic compounds such as the pollutant p-nitrophenol, biofilm-anchored hybrid Cd0.9Zn0.1S quantum dots and gold nanoparticles to degrade organic dyes and biofilm-anchored CdSeS@ZnS quantum dots in a semi-artificial photosynthesis system for hydrogen production. Our work demonstrates how the ability of biofilms to grow in scalable and complex spatial arrangements can be exploited for catalytic applications and clearly illustrates the design utility of segregating high-energy nano-objects from injury-prone cellular components by engineering anchoring points in an extracellular matrix. 相似文献
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近来对基于表面等离子体的微纳光学器件研究很多,这类器件在量子计算和量子通信中将会有着重要用途。本文对一种简单新颖的圆形腔间接耦合的结构进行了研究,发现其具有很好的滤波作用,透射谱的半峰全宽可以控制在10nm~20nm,从而显示出一定的应用价值。通过并联结构可以将此结构扩展,从而得出多通道的解复用器。 相似文献
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在光学系统中,SOI(绝缘体上的半导体)上制备集成的MMI(多模干涉)型光耦合器已成为一种愈来愈引人注目的无源器件.由于Si和SiO2 之间具有大的折射率差,在SOI波导中可以采用SiO2 薄膜( <1.0 μm)作限制层,这与超大规模集成电路工艺相兼容.描述了采用SOI技术制备集成的MMI型光耦合器和光开关的设计和制造结果.业已证实,2× 2MMI MZI(多模干涉 麦赫 曾德干涉)型热光开关的开关时间小于 2 0 μs. 相似文献
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Ever since its first proposal in 1976, Jackiw-Rebbi zero-mode has been drawing extensive attention for its charming properties including charge fractionalization, topologically protected zero-energy and possible non-Abelian statistics. We investigate these properties through the Jackiw-Rebbi zero-modes in quantum spin Hall insulators. Though charge fractionalization is not manifested, Jackiw-Rebbi zero-mode''s zero-energy nature leads to a double-frequency Aharonov-Bohm effect, implying that it can be viewed as a special case of Majorana zero-mode without particle-hole symmetry. Such relation is strengthened for Jackiw-Rebbi zero-modes also exhibiting non-Abelian properties in the absence of superconductivity. Furthermore, in the condition that the degeneracy of Jackiw-Rebbi zero-modes is lifted, we demonstrate a novel non-Abelian braiding with continuously tunable fusion rule, which is a generalization of Majorana zero-modes’ braiding properties. 相似文献
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Aminuddin A. Kayani Khashayar Khoshmanesh Stephanie A. Ward Arnan Mitchell Kourosh Kalantar-zadeh 《Biomicrofluidics》2012,6(3)
The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. 相似文献