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41.
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Lili Gao Bin Chen Michael Lerche Esen E. Alp Wolfgang Sturhahn Jiyong Zhao Hasan Yava? Jie Li 《Journal of synchrotron radiation》2009,16(6):714-722
The applications of nuclear resonant scattering in laser‐heated diamond anvil cells have provided an important probe for the magnetic and vibrational properties of 57Fe‐bearing materials under high pressure and high temperature. Synchrotron X‐ray diffraction is one of the most powerful tools for studying phase stability and equation of state over a wide range of pressure and temperature conditions. Recently an experimental capability has been developed for simultaneous nuclear resonant scattering and X‐ray diffraction measurements using synchrotron radiation. Here the application of this method to determine the sound velocities of compressed Fe3C is shown. The X‐ray diffraction measurements allow detection of microscale impurities, phase transitions and chemical reactions upon compression or heating. They also provide information on sample pressure, grain size distribution and unit cell volume. By combining the Debye velocity extracted from the nuclear resonant inelastic X‐ray scattering measurements and the structure, density and elasticity data from the X‐ray diffraction measurements simultaneously obtained, more accurate sound velocity data can be derived. Our results on few‐crystal and powder samples indicate strong anisotropy in the sound velocities of Fe3C under ambient conditions. 相似文献
43.
We synthesize LiTal-x FexO3-σ (LTFO) remain single phase up to x = 0.09 ceramics by the conventional solid-state reaction method. The samples The magnetic measurements show that the doping of Fe successfully realizes ferromagnetism of LTFO at room temperature. The dielectric measurements indicate that LTFO is ferroelectric, similarly to LiTaO3 (LTO), but its ferroelectric Curie temperature seems to decrease with the increasing Fe content. By means of doping Fe ions into LTO, the coexistence of spontaneous electric polarization and spontaneous magnetic moment is realized at room temperature. 相似文献
44.
45.
Xia Yang Jun Xu Liujiang Xi Yanli Yao Qingdan Yang C. Y. Chung Chun-Sing Lee 《Journal of nanoparticle research》2012,14(6):1-6
One-dimensional ordered quantum-ring chains are fabricated on a quantum-dot superlattice template by molecular beam epitaxy. The quantum-dot superlattice template is prepared by stacking multiple quantum-dot layers and quantum-ring chains are formed by partially capping quantum dots. Partially capping InAs quantum dots with a thin layer of GaAs introduces a morphological change from quantum dots to quantum rings. The lateral ordering is introduced by engineering the strain field of a multi-layer InGaAs quantum-dot superlattice. 相似文献
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47.
Metal/semiconductor hybrids consisting of self-assembled CdS nanoparticles on Cd nanowires 下载免费PDF全文
We report on the synthesis and the characterisation of
metal/semiconductor hybrids consisting of self-assembled CdS
nanoparticles on Cd nanowires, which are grown by thermal
evaporation of the mixture of CdS and Cr. The growth of the hybrids
is attributed to the decomposition of CdS at high temperature and
the strain relieving that arises mainly from the lattice mismatch
between Cd and CdS. Temperature dependence of zero-field resistance
of single nanohybrid indicates that the as-produced Cd/CdS
nanohybrid undergoes a metal--semiconductor transition as a natural
consequence of hybrid from metallic Cd and semiconducting CdS. The
metal/semiconductor hybrid property provides a promising basis for
the development of novel nanoelectronic devices. 相似文献
48.
Admissible consensus analysis and consensualizing controller design problems for high-order linear time-invariant singular swarm systems are investigated. Firstly, by projecting the state of a singular swarm system onto a consensus subspace and a complement consensus subspace, a necessary and sufficient condition for admissible consensus is presented in terms of linear matrix inequalities (LMIs). An approach to decrease the calculation complexity is proposed, by which only three LMIs independent of the number of agents need to be checked. Then, by using the changing variable method, sufficient conditions for admissible consensualization are shown. An explicit expression of the consensus function is given, and it is shown that the modes of the consensus function can be arbitrarily placed if each agent is R-controllable and impulse controllable and the interaction topology has a spanning tree. Finally, theoretical results are applied to deal with cooperative control problems of multi-agent supporting systems. 相似文献
49.
Ba0.70Sr0.30TiO3 (BST) thin films doped by Co (BSTC) are fabricated by sol-gel method on a Pt/Ti/SiO2/Si substrate. A strong correlation is observed among the microstructure, dielectric, ferroelectric, ferromagnetic properties and Co concentration. The dielectric constant of BST thin films can be tailored from 343 to 119 by manipulating the Co concentration. The dielectric loss of BSTC thin films are still kept below 0.020 and the tunability is above 30% at a dc-applied electric field of 500 kV/cm. With increasing Co doping up to 10 mol%, the coexistence of ferromagnetism and ferroelectrics is found. Suitable dielectric constant, low-dielectric loss, and high tunability of this kind of thin films can be useful for potential tunable applications. 相似文献
50.
进入新世纪,传统教学模式已不适应现代教育教学的需要,多媒体辅助教学应运而生,且已融人现代教育技术,参与到整个教学过程.电教媒体不再局限于视听范畴,而呈现多媒体化、超文本化、网络化、交互性等新特点.应用多媒体课件,化抽象为形象、微观为宏观、静态为动态、不可操作为可操作过程,对激发学生的学习兴趣和积极性,化解知识难点,提高综合能力,推进素质教育具有重要意义. 相似文献