다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles is a powerful technique for chemical and biological sensing experiments. Moreover, the LSPR is responsible for the electromagnetic-field enhancement that leads to surface-enhanced Raman scattering (SERS) and other surface-enhanced spectroscopic processes. This review describes recent fundamental spectroscopic studies that reveal key relationships governing the LSPR spectral location and its sensitivity to the local environment, including nanoparticle shape and size. We also describe studies on the distance dependence of the enhanced electromagnetic field and the relationship between the plasmon resonance and the Raman excitation energy. Lastly, we introduce a new form of LSPR spectroscopy, involving the coupling between nanoparticle plasmon resonances and adsorbate molecular resonances. The results from these fundamental studies guide the design of new sensing experiments, illustrated through applications in which researchers use both LSPR wavelength-shift sensing and SERS to detect molecules of chemical and biological relevance.

https://www.photonics.ethz.ch/fileadmin/user_upload/Courses/NanoOptics/willets.pdf

Localized Surface Plasmon Resonance Spectroscopy and Sensing

The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.

Surface-Enhanced Raman Spectroscopy

Surface-enhanced Raman spectroscopy.

Coinage metals, such as Au, Ag, and Cu, have been important materials throughout history.1 While in ancient cultures they were admired primarily for their ability to reflect light, their applications have become far more sophisticated with our increased understanding and control of the atomic world. Today, these metals are widely used in electronics, catalysis, and as structural materials, but when they are fashioned into structures with nanometer-sized dimensions, they also become enablers for a completely different set of applications that involve light. These new applications go far beyond merely reflecting light, and have renewed our interest in maneuvering the interactions between metals and light in a field known as plasmonics.2–6

In plasmonics, the metal nanostructures can serve as antennas to convert light into localized electric fields (E-fields) or as waveguides to route light to desired locations with nanometer precision. These applications are made possible through a strong interaction between incident light and free electrons in the nanostructures. With a tight control over the nanostructures in terms of size and shape, light can be effectively manipulated and controlled with unprecedented accuracy.3,7 While many new technologies stand to be realized from plasmonics, with notable examples including superlenses,8 invisible cloaks,9 and quantum computing,10,11 conventional technologies like microprocessors and photovoltaic devices could also be made significantly faster and more efficient with the integration of plasmonic nanostructures.12–15 Of the metals, Ag has probably played the most important role in the development of plasmonics, and its unique properties make it well-suited for most of the next-generation plasmonic technologies.16–18

1.1. What is Plasmonics?
Plasmonics is related to the localization, guiding, and manipulation of electromagnetic waves beyond the diffraction limit and down to the nanometer length scale.4,6 The key component of plasmonics is a metal, because it supports surface plasmon polariton modes (indicated as surface plasmons or SPs throughout this review), which are electromagnetic waves coupled to the collective oscillations of free electrons in the metal.

While there are a rich variety of plasmonic metal nanostructures, they can be differentiated based on the plasmonic modes they support: localized surface plasmons (LSPs) or propagating surface plasmons (PSPs).5,19 In LSPs, the time-varying electric field associated with the light (Eo) exerts a force on the gas of negatively charged electrons in the conduction band of the metal and drives them to oscillate collectively. At a certain excitation frequency (w), this oscillation will be in resonance with the incident light, resulting in a strong oscillation of the surface electrons, commonly known as a localized surface plasmon resonance (LSPR) mode.20 This phenomenon is illustrated in Figure 1A. Structures that support LSPRs experience a uniform Eo when excited by light as their dimensions are much smaller than the wavelength of the light.



Figure 1

Schematic illustration of the two types of plasmonic nanostructures discussed in this article as excited by the electric field (Eo) of incident light with wavevector (k). In (A) the nanostructure is smaller than the wavelength of light and the free electrons ...



In contrast, PSPs are supported by structures that have at least one dimension that approaches the excitation wavelength, as shown in Figure 1B.4 In this case, the Eo is not uniform across the structure and other effects must be considered. In such a structure, like a nanowire for example, SPs propagate back and forth between the ends of the structure. This can be described as a Fabry-Perot resonator with resonance condition l=nλsp, where l is the length of the nanowire, n is an integer, and λsp is the wavelength of the PSP mode.21,22 Reflection from the ends of the structure must also be considered, which can change the phase and resonant length. Propagation lengths can be in the tens of micrometers (for nanowires) and the PSP waves can be manipulated by controlling the geometrical parameters of the structure.23

/pdf/controlling-the-synthesis-and-assembly-of-silver-1ktlgomyt6.pdf

Controlling the synthesis and assembly of silver nanostructures for plasmonic applications

Hydrogen bonding in cis-bis(l-alaninato)copper(II): a single crystal neutron diffraction study

Carbon-supported platinum oxide–tin oxide samples have been studied as electrocatalysts for methanol oxidation. The Teflon-bonded electrodes are found to be poor electrocatalysts. X-Ray photoelectron and Mossbauer spectroscopy, together with electron microscopy, have been used to determine the nature of the bimetallic crystallites. Differences in the activity of various Pt–Sn-containing electrodes for methanol oxidation are discussed.

Characterisation of carbon-supported Pt–Sn bimetallic catalysts for the electrochemical oxidation of methanol

The structural and magnetic properties of the two Ir(V) perovskites Ba2ScIrO6 and Sr2ScIrO6 were established. The structures were refined using a combined neutron and synchrotron data set. At room temperature the former has a cubic structure in space group Fm3m with a = 8.1450(3) A, and the latter is monoclinic in P21/n with a = 5.6606(3) A, b = 5.6366(3) A, c = 7.9720(4) A, and β = 89.977(5)°. Magnetization measurements show both oxides have magnetic moments close to zero as a consequence of strong spin–orbit coupling that results in a Jeff ≈ 0 ground state. The distortion of the IrO6 octahedra in Sr2ScIrO6 is insufficient to generate crystal field splitting strong enough to quench the spin–orbit coupling.

/pdf/spin-orbit-coupling-controlled-ground-state-in-the-ir-v-2yzedtszyk.pdf

Spin-Orbit Coupling Controlled Ground State in the Ir(V) Perovskites A2ScIrO6 (A = Ba or Sr).

Structural studies of the rhombohedral and orthorhombic monouranates: CaUO4, α-SrUO4, β-SrUO4 and BaUO4

Zinc K-edge X-ray absorption fine structure (XAFS) experiments were performed in the solid and solution states at low temperature (10 K), on dimeric and monomeric anti-inflammatory Zn(II) complexes of indomethacin [1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid = IndoH] of the formula [Zn2(Indo)4L2] [L = pyridine (Py), N,N-dimethylacetamide (DMA)], [Zn(Indo)2L2] [L = ethanol (EtOH), methanol (MeOH)], and Zn(II) acetate dihydrate [Zn(OAc)2(OH2)2]. The bond distances and angles obtained from multiple-scattering fits to the XAFS data of the Zn(II) dimeric complexes in the solid and solution states exhibit excellent correspondence with those obtained from single crystal diffraction studies. The Zn···Zn separations of 2.97 and 2.96 A and carboxylato group O−C−O angles of 125° for powdered [Zn2(Indo)4(Py)2] and [Zn2(Indo)4(DMA)2] agree well with the XRD values of 2.969(1) and 2.9686(6) A and 125.8(4)° and 126.1(2)°, respectively. The calculated Zn−ORCOO and Zn−L bond distances of 2.03 and 2.04 A...

Brendan J. Kennedy

Papers

Hydrogen bonding in cis-bis(l-alaninato)copper(II): a single crystal neutron diffraction study

Characterisation of carbon-supported Pt–Sn bimetallic catalysts for the electrochemical oxidation of methanol

Spin-Orbit Coupling Controlled Ground State in the Ir(V) Perovskites A2ScIrO6 (A = Ba or Sr).

Structural studies of the rhombohedral and orthorhombic monouranates: CaUO4, α-SrUO4, β-SrUO4 and BaUO4

XAFS Studies of Anti-Inflammatory Dinuclear and Mononuclear Zn(II) Complexes of Indomethacin