350 research outputs found
Generalized Deligne-Hitchin Twistor Spaces: Construction and Properties
In this paper, we generalize the construction of Deligne-Hitchin twistor
space by gluing two certain Hodge moduli spaces. We investigate such
generalized Deligne-Hitchin twistor space as a complex analytic manifold. More
precisely, we show it admits holomorphic sections with weight-one property and
semi-negative energy, and it carries a balanced metric, and its holomorphic
tangent bundle (for the case of rank one) is stable. Moreover, we also study
the automorphism groups of the Hodge moduli spaces and the generalized
Deligne-Hitchin twistor space.Comment: An update of the revised version with some gaps fixed in 2022,
comments welcome
Moduli Spaces of Parabolic Bundles over with Five Marked Points
This paper considers the moduli spaces (stacks) of parabolic bundles
(parabolic logarithmic flat bundles with given spectrum, parabolic regular
Higgs bundles) with rank and degree over with five
marked points. The foliation and stratification structures on these moduli
spaces (stacks) are investigated. In paricular, we confirm Simpson's conjecture
for moduli space of parabolic logarithmic flat bundles with certain non-special
weight system
(Formato-κ2 O,O′)bis(1,10-phenanthroline-κ2 N,N′)manganese(II) perchlorate
In the title complex, [Mn(CHO2)(C12H8N2)2]ClO4, the MnII cation is chelated by two 1,10-phenanthroline (phen) ligands and one formate anion in a distorted MnN4O2 octahedral geometry. The two phen planes are oriented at a dihedral angle of 57.48 (11)°. The perchlorate anion links with the Mn complex cation via weak C—H⋯O hydrogen bonding
[2-(Tetrazol-1-yl)acetato-κO]tris(triphenylphosphine-κP)silver(I) monohydrate
The AgI atom in the title compound, [Ag(C3H3N4O2)(C18H15P)3]·H2O, exists in a distorted tetrahedral environment. The uncoordinated water molecule forms only one hydrogen bond to the uncoordinated carbonyl O atom
Realization of edge states along a synthetic orbital angular momentum dimension
The synthetic dimension is a rising method to study topological physics,
which enables us to implement high-dimensional physics in low-dimensional
geometries. Photonic orbital angular momentum (OAM), a degree of freedom
characterized by discrete yet unbounded, serves as a suitable synthetic
dimension. However, a sharp boundary along a synthetic OAM dimension has not
been demonstrated, dramatically limiting the investigation of topological edge
effects in an open boundary lattice system. In this work, we make a sharp
boundary along a Floquet Su-Schrieffer-Heeger OAM lattice and form approximate
semi-infinite lattices by drilling a pinhole on the optical elements in a
cavity. The band structures with zero () energy boundary states are
measured directly, benefiting from the spectra detection of the cavity.
Moreover, we obtain the edge modes moving from the gap to the bulk by
dynamically changing the boundary phase, and we reveal that interference near
the surface leads to spectrum discretization. Our work provides a new
perspective to observe edge effects and explore practical photonics tools
KIC 10417986: Spectroscopic confirmation of the nature of the binary system with a {\delta} Scuti component
KIC 10417986 is a short orbital period (0.0737 d) ellipsoidal variable star
with a {\delta} Scuti and {\gamma} Doradus hybrid pulsations component
discovered by Kepler. The ground-based spectroscopic observations were carried
out in the winters of 2020 and 2021 to investigate the binary nature of this
star. We derive the orbital parameters using the rvfit code with a result of K1
= 29.7 1.5 km/s, {\gamma} = -18.7 1.7 km/s, and confirm an orbital
period of 0.84495 d instead of the result given by Kepler. The atmospheric
parameters of the primary are determined by the synthetic spectra fitting
technique with the estimated values of Teff = 7411 187 K, log g = 4.2
0.3 dex, [M/H] = 0.08 0.09 dex and vsini = 52 11 km/s. KIC
10417986 is a circular orbit binary system. From the single-lined nature and
mass function of the star, the derived orbital inclination is 26 6{\deg},
and the mass of the secondary is from 0.43 to 0.7 M_sun, which should be a
late-K to early-M type star. Fourteen frequencies are extracted from Kepler
light curves, of which six independent frequencies in the high-frequency region
are identified as the p-mode pulsations of {\delta} Scuti star, and one
independent frequency in the low-frequency region (f2 = 1.3033 c/d) is probably
the rotational frequency due to the starspots rather than the ellipsoidal
effect or g-mode of {\gamma} Doradus.Comment: 18 pages, 8 figure
Plasmonic photoluminescence for recovering native chemical information from surface-enhanced Raman scattering
表面增强拉曼光谱(SERS)可以提供高达单分子的检测灵敏度和特异的分子指纹信息,是一个非常有前景的分析技术。SERS增强主要源自贵金属纳米结构的局域表面等离激元共振(LSPR)效应。虽然SERS研究者早已意识到该效应强烈依赖于激光波长,并对不同频率的拉曼谱峰增强效果不同,但是迄今为止仍缺乏有效的方法对SERS谱峰相对强度进行可靠的矫正,也常有文献错误解读SERS强度信息,从而过度或错误地解释实验结果。
在该工作中,任斌教授课题组采用单粒子光谱技术从实验上直接检测SERS光谱和金属纳米粒子的光致发光谱(PL),通过定量研究两者的关联,提出了一种普适的方法矫正LSPR对不同拉曼谱峰相对强度的影响,为理解表面物种构型和作用方式提供了本征的化学指纹信息。【Abstract】Surface-enhanced Raman scattering (SERS) spectroscopy has attracted tremendous interests as a highly sensitive label-free tool. The local field produced by the excitation of localized surface plasmon resonances (LSPRs) dominates the overall enhancement of SERS. Such an electromagnetic enhancement is unfortunately accompanied by a strong modification in the relative intensity of the original Raman spectra, which highly distorts spectral features providing chemical information. Here we propose a robust method to retrieve the fingerprint of intrinsic chemical information from the SERS spectra. The method is established based on the finding that the SERS background originates from the LSPR-modulated photoluminescence, which contains the local field information shared also by SERS. We validate this concept of retrieval of intrinsic fingerprint information in well controlled single metallic nanoantennas of varying aspect ratios. We further demonstrate its unambiguity and generality in more complicated systems of tip-enhanced Raman spectroscopy (TERS) and SERS of silver nanoaggregates.该工作得到国家自然科学基金委(项目批准号:21633005、21621091和J1310024)、科技部(项目批准号:2013CB933703、2016YFA0200601)、教育部等部门的大力资助与支持
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