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61.
62.
We analytically show that quantum diffusion in the coupled system composed of two identical chains exhibits a well-defined periodic oscillation in both transverse and longitudinal directions with a frequency determined by the interchain hopping strength, no matter whether the chains are periodic or non-periodic. We illustrate the result through numerical work on the coupled periodic chains and the quasiperiodic Aubry-Andre-Harper(AAH) chains with various modulations of onsite potentials supporting extended, critical, and localized states. We further numerically show that quantum diffusion in the coupled chains of different degrees of disorder W exhibits an exponential decay oscillation similar to the behavior of an underdamped harmonic oscillator, with a decay time inversely proportional to the square of W and a slight frequency change proportional to the square of W. Moreover, quantum diffusions in the coupled systems composed of two different chains are numerically studied, including periodic/disordered chains, periodic/AAH chains, and two different AAH chains, which exhibit the same behavior of underdamped periodic oscillation if the onsite potential difference between two chains is smaller than the interchain hoping strength.Existence of this universal periodic oscillation is a result of spectral splitting of the iso-spectra of two chains determined by interchain hopping, independent of system size, boundary condition, and intrachain onsite potentials. Because the oscillation frequency and spreading distance of wavepacket can be tuned separately by interchain hopping and intrachain potentials, the periodic oscillation of quantum diffusion in coupled chains is expected to find applications in control of quantum states and in designing nanoscale quantum devices. 相似文献
63.
JiaoLong Zeng Cheng Gao PengFei Liu YongJun Li CongSen Meng Yong Hou DongDong Kang JianMin Yuan 《中国科学:物理学 力学 天文学(英文版)》2022,(3)
The internal solar structure predicted by the standard solar model disagrees with the helioseismic observations even by utilizing the most updated physical inputs, such as the opacity and element abundances. By increasing the Rosseland mean, the decade-old open problem of the missing opacity can be resolved. Herein, we propose that the continuum electrons in the radiative processes lose phases and coherence as matter waves, giving rise to a phenomenon of transient spatial localization. It not only enhances the continuum opacity but also increases the line widths of the bound-bound transitions. We demonstrate our theoretical formulation by investigating the opacity of solar mixtures in the interior. The Rosseland mean demonstrates an increase of 10%-26% in the range of 0.3 R⊙-0.75 R⊙. The results are compared with the recent experimental data and the existing theoretical models. Our findings provide novel clues to the open problem of the missing opacity in the solar interior and new insight on the radiative opacity in the hot dense-plasma regime. 相似文献
64.
Tuning the bandgap in layered transition metal dichalcogenides(TMDCs) is crucial for their versatile applications in many fields. The ternary formation is a viable method to tune the bandgap as well as other intrinsic properties of TMDCs, because the multi-elemental characteristics provide additional tunability at the atomic level and advantageously alter the physical properties of TMDCs. Herein, ternary TixZr1-xSe2 single crystals were synthesized using the chem... 相似文献
65.
66.
在吸收光谱技术中,使用光学腔增长激光与气体介质的作用路径,可提升探测灵敏度.然而,高反射率腔镜会存在双折射效应,导致光学腔产生两个本征偏振态,入射光在两个偏振方向相移的不同会导致腔模的分裂,会引起腔增强光谱信号以及腔衰荡光谱信号的扭曲.本文观测到了双折射效应下腔增强信号的频率分裂现象,并给出了函数模型,拟合结果表明其可以准确得到透射腔模中不同偏振光的比例.根据上述比例,可给出考虑不同耦合效率、双折射效应下的腔衰荡信号模型,实验结果表明相较于传统e指数模型,本文模型可更精确描述腔衰荡信号,得到拟合残差的标准偏差最大抑制了9倍.该分析有利于改善腔衰荡信号信噪比和不确定性,提升其浓度反演准确度. 相似文献
67.
68.
二维过渡金属硫化物(TMDC)材料因为独特的激子效应和材料学性质,在太阳电池、光催化、传感器、柔性电子器件等领域得到广泛的应用。层数对其性质有显著的调控作用,自动检测识别所需层数的样品是其从实验室走进半导体制造工业的重要技术需求。本文结合反射高光谱成像技术与图像处理算法,发展了一种二维TMDC薄层样品的显微成像自动检测技术。基于自主搭建的反射高光谱成像系统,对制备的不同层数TMDC标准样品进行了光学对比度的系统研究,阐明了层数的差分反射光谱机理,提出了可靠的层数判定方法。基于传统边缘检测技术优化设计了一套图像处理算法,实现了TMDC样品的图像检测及层数鉴定。本文方法具有普遍性、实用性,结合自动对焦的扫描控制,能够实现大规模的自动化样品检测,这也为其他表面目标的显微识别和检测提供了新的灵感和参考。 相似文献
69.
A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrication.Herein,taking Ni Mo O4nanorods for example,we demonstrated the advantages of the microwaveassisted hydrothermal synthesis method compared to the traditional hydrothermal approaches.Both monoclinic structured Ni Mo O4in the nanorods morphology are found for these samples but it is more time-saving and efficient in the Ni-Mo synergism for the catalyst obtained by mi... 相似文献
70.
Xiangwen Kong Fang Yu Shengtong Niu Fan Gong Shuang Yang Jinggong Liu Benlong Luo Xinqiang Fang 《中国化学快报》2022,33(6):2997-3002
Copper-catalyzed divergent annulations between α-diketones and alkynyl α-diketones have been achieved, delivering a series of highly functionalized and biologically important cis-hexahydro-2Hcyclopenta[b]furan(HCPF) and 2-hydroxydihydrofuran-3(2H)-one(HDFO) products with high levels of stereoselectivity under identical conditions. The protocol features the use of earth-abundant copper catalyst, mild conditions, shortening synthetic routes in constructing different molecular frameworks, and reduc... 相似文献