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151.
152.
By using the transfer matrix method, within the framework
of the dielectric continuum approximation, uniform forms for the
interface optical (IO) phonon modes as well as the corresponding electron-IO
phonon interaction Hamiltonians in n-layer coupling low-dimensional systems
(including the coupling quantum well (CQW), coupling quantum-well wire
(CQWW), and coupling quantum dot (CQD)) have been presented. Numerical
calculations on the three-layer asymmetrical AlGaAs/GaAs systems are
performed, and the analogous characteristics for limited frequencies of IO phonon in the three types of systems (CQW, CQWW, and CQD) when the
wave-vector and the quantum number approach zero or infinity are analyzed
and specified. 相似文献
153.
本文详细介绍了一种利用微电子加工工艺制作的硅微型两自由度振动轮式陀螺仪的新结构 ,分析了该种陀螺仪的工作原理 ,推导了陀螺仪动力学方程 ,并讨论了梳状谐振器的工作机理和陀螺仪模拟力反馈的闭环控制方案 ;目前已制作完成了该型陀螺仪的原理样机 相似文献
154.
提出一种新型GaAs/GaAlAs子带间光吸收的红外光电导探测机理,利用MOCVD系统进行器件材料的生长,研制了200μm×200μm的台面形式单管,测到了明显的红外光电流信号及阱间共振遂穿效应造成的负阻震荡现象,对器件的性能测试结果表明,器件的光电流响应和信噪比随着阱数增加而增加,器件噪声比常规GaAs/GaAlAs量子阱红外探测器低一个数量级. 相似文献
155.
运用多维数字信号处理理论,分析了PAL信号亮度和色度频谱的二维交错结构。给出了用于二维亮色分离的312行延迟和313行延迟场梳状滤波器的原理框图,推导出了其二维频率响应公式。指出了场梳状滤波比行、帧梳状滤波的优越之处。 相似文献
156.
Adam A. Dundas Valentina Cuzzucoli Crucitti Simon Haas Jean‐Frdric Dubern Arsalan Latif Manuel Romero Olutoba Sanni Amir M. Ghaemmaghami Paul Williams Morgan R. Alexander Ricky Wildman Derek J. Irvine 《Advanced functional materials》2020,30(36)
A flow‐focusing microfluidic device is used to produce functionalized monodisperse polymer particles with surface chemistries designed to control bacterial biofilm formation. This is achieved by using molecularly designed bespoke surfactants synthesized via catalytic chain transfer polymerization. This novel approach of using polymeric surfactants, often called surfmers, containing a biofunctional moiety contrasts with the more commonly employed emulsion methods. Typically, the surface chemistry of microparticles are dominated by unwanted surfactants that dilute/mask the desired surface response. Time of flight secondary ion mass spectrometry (ToF‐SIMS) analysis of particles demonstrates that the comb‐graft surfactant is located on the particle surface. Biofilm experiments show how specifically engineered surface chemistries, generated by the surfactants, successfully modulate bacterial attachment to both polymer films, and microparticles. Thus, this paper outlines how the use of designed polymeric surfactants and droplet microfluidics can exert control over both the surface chemistry and size distribution of microparticle materials, demonstrating their critical importance for controlling surface‐cell response. 相似文献
157.
Lingqiao Li Zhe Qiang Xi Chen Kailong Jin Muzhou Wang John M. Torkelson 《Journal of polymer science. Part A, Polymer chemistry》2020,58(20):2887-2905
Thermo-cleavable bottlebrush polymers were synthesized by a facile grafting-to method via radical coupling and atom transfer radical polymerization (ATRP) without small-molecule synthesis involved. Bottlebrushes were achieved by coupling backbones of poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), which contain nitroxide radicals, and ATRP-synthesized side chains, which can be halogen-abstracted to generate carbon-centered radicals. Bottlebrushes were prepared using homopolymer or block copolymer side chains. Alkoxyamine covalent bonds resulting from radical coupling are thermo-reversible at high temperature, and grafting density may be tuned by annealing of post-synthesis bottlebrush, with the bottlebrush regime going from loose bottlebrush to dense comb and loose comb. The effects of confinement on the Tg and fragility of films of polystyrene bottlebrush were studied by ellipsometry; comparisons were made to thermally cleaved linear components obtained directly after annealing. Relative to linear polymer, bottlebrush topology reduces bulk fragility and suppresses Tg- and fragility-confinement effects. The correlation between the strengths of the confinement effects is consistent with other film studies of linear and non-linear polymers and supports the notion that fragility is a fundamental property underlying perturbations to Tg. Besides providing a platform for advancing fundamental scientific understanding, our synthetic strategy may afford novel applications of bottlebrushes via incorporated dynamic chemistry. 相似文献
158.
LUO Wenjun LIU Guanli 《中国通信》2014,(9):104-111
Quantum cryptography and quantum search algorithm are considered as two important research topics in quantum information science. An asymmetrical quantum encryption protocol based on the properties of quantum one-way function and quantum search algorithm is proposed. Depending on the no-cloning theorem and trapdoor one-way functions of the public- key, the eavesdropper cannot extract any private-information from the public-keys and the ciphertext. Introducing key-generation randomized logarithm to improve security of our proposed protocol, i.e., one private- key corresponds to an exponential number of public-keys. Using unitary operations and the single photon measurement, secret messages can be directly sent from the sender to the receiver. The security of the proposed protocol is proved that it is informationtheoretically secure. Furthermore, compared the symmetrical Quantum key distribution, the proposed protocol is not only efficient to reduce additional communication, but also easier to carry out in practice, because no entangled photons and complex operations are required. 相似文献
159.
《Physics and Chemistry of Liquids》2012,50(2):222-241
The measurement of ionic self-diffusion coefficient D of the trivalent lanthanide ion 152Eu(III) in asymmetrical electrolytes of Eu(ClO4)3 in hydro-organic water–dioxane mixtures (at a low dielectric constant) at 298.15?K, by the open-end capillary method gives evidence of the progressive association of ion pairs. The study of the different physicochemical properties in all the domains of composition shows the existence of three distinct behaviours. The application of association theory to such an asymmetrical electrolyte (3?:?1) with a polyvalent cation enables us to delimit the validity of the Bjerrum and Fuoss's association theories. Since there is similarity of the coordination chemistry of trivalent lanthanide and actinide ions, this study comes within the framework of previous works of the investigation of structure properties of the f-elements in solution carried out in some previous papers. 相似文献
160.
研究了磁光耦合强度对磁光光纤布喇格光栅中模式转换光反射光谱特性的影响.根据磁光耦合模理论并结合光纤布喇格光栅的传播特性,数值分析了磁光光纤布喇格光栅的磁控特性,得到了3 dB带宽可调的滤波器.采用级联磁光光纤布喇格光栅构造磁控梳状滤波器,实现了40 Gbps归零数据信号的全光时钟提取仿真,分析了时钟信号的抖动性能与磁光耦合参量的关系. 相似文献